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Sample records for resonance guided focused

  1. Renal ablation using magnetic resonance-guided high intensity focused ultrasound: Magnetic resonance imaging and histopathology assessment

    OpenAIRE

    Saeed, Maythem; Krug, Roland; Do, Loi; Steven W. Hetts; Wilson, Mark W.

    2016-01-01

    AIM: To use magnetic resonance-guided high intensity focused ultrasound (MRg-HIFU), magnetic resonance imaging (MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue.

  2. Review of magnetic resonance-guided focused ultrasound in the treatment of uterine fibroids

    Directory of Open Access Journals (Sweden)

    Pedro Felipe Magalhães Peregrino

    Full Text Available Uterine leiomyoma is the most frequently occurring solid pelvic tumor in women during the reproductive period. Magnetic resonance-guided high-intensity focused ultrasound is a promising technique for decreasing menorrhagia and dysmenorrhea in symptomatic women. The aim of this study is to review the role of Magnetic resonance-guided high-intensity focused ultrasound in the treatment of uterine fibroids in symptomatic patients. We performed a review of the MEDLINE and Cochrane databases up to April 2016. The analysis and data collection were performed using the following keywords: Leiomyoma, High-Intensity Focused Ultrasound Ablation, Ultrasonography, Magnetic Resonance Imaging, Menorrhagia. Two reviewers independently performed a quality assessment; when there was a disagreement, a third reviewer was consulted. Nineteen studies of Magnetic resonance-guided high-intensity focused ultrasound-treated fibroid patients were selected. The data indicated that tumor size was reduced and that symptoms were improved after treatment. There were few adverse effects, and they were not severe. Some studies have reported that in some cases, additional sessions of Magnetic resonance-guided high-intensity focused ultrasound or other interventions, such as myomectomy, uterine artery embolization or even hysterectomy, were necessary. This review suggests that Magnetic resonance-guided high-intensity focused ultrasound is a safe and effective technique. However, additional evidence from future studies will be required before the technique can be recommended as an alternative treatment for fibroids.

  3. Magnetic Resonance-guided high intensity focused ultrasound in the presence of biopsy markers

    NARCIS (Netherlands)

    Mougenot, C; Moonen, Chrit

    2017-01-01

    Background: Magnetic Resonance guided High Intensity Focused ultrasound (MR-HIFU) offers precise non-invasive thermotherapy for clinical applications such as the treatment of breast lesions. However, patients with a biopsy marker are usually not eligible for MR-HIFU treatment. This study

  4. Bone metastasis treatment using magnetic resonance-guided high intensity focused ultrasound

    NARCIS (Netherlands)

    Yeo, Sin Yuin; Elevelt, Aaldert; Donato, Katia; van Rietbergen, Bert; ter Hoeve, Natalie D.; van Diest, Paul J.|info:eu-repo/dai/nl/075281775; Grüll, Holger

    2015-01-01

    Objectives: Bone pain resulting from cancer metastases reduces a patient's quality of life. Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) is a promising alternative palliative thermal treatment technique for bone metastases that has been tested in a few clinical studies.

  5. Can magnetic resonance image-guided focused ultrasound surgery replace local oncology treatments? A review.

    Science.gov (United States)

    Alongi, Filippo; Russo, Giorgio; Spinelli, Antonio; Borasi, Giovanni; Scorsetti, Marta; Gilardi, Maria Carla; Messa, Cristina

    2011-01-01

    Magnetic resonance image-guided focused ultrasound surgery (MRgFUS) is an innovative technology in the new panorama of treatment using ultrasound. It combines two well-known and distinct methodologies: high-intensity focused ultrasound (HIFU) and a magnetic resonance imaging system (MRI). This review on MRgFUS is focused on the technical aspects and the current clinical applications in oncology. More precisely, the advantages/disadvantages of MRgFUS compared to other local approaches such as surgery and radiotherapy are discussed in detail.

  6. Potential of magnetic resonance-guided focused ultrasound for intracranial hemorrhage: an in vitro feasibility study.

    Science.gov (United States)

    Harnof, Sagi; Hananel, Arik; Zilby, Zion; Kulbatski, Iris; Hadani, Moshe; Kassell, Neal

    2014-01-01

    Intracranial hemorrhage has a mortality rate of up to 40-60% due to the lack of effective treatment. Magnetic resonance-guided focused ultrasound may offer a breakthrough noninvasive technology, by allowing accurate delivery of focused ultrasound, under the guidance of real-time magnetic resonance imaging. The purpose of the current study was to optimize the acoustic parameters of magnetic resonance-guided focused ultrasound for effective clot liquefaction, in order to evaluate the feasibility of magnetic resonance-guided focused ultrasound for thrombolysis. Body (1·1 MHz) and brain (220 kHz) magnetic resonance-guided focused ultrasound systems (InSightec Ltd, Tirat Carmel, Israel) were used to treat tube-like (4 cc), round (10 cc), and bulk (300 cc) porcine blood clots in vitro, using burst sonications of one-second to five-seconds, a duty cycle of 5-50%, and peak acoustic powers between 600 and 1200 W. Liquefied volumes were measured as hyperintense regions on T2-weighted magnetic resonance images for body unit sonications (duration of one-second, duty cycle of 10%, and power of 500-1200 W). Liquefaction efficiency was calculated for brain unit sonications (duration of one-second, duty cycle of 10%, power of 600 W, and burst length between 0·1 ms and 100 ms). Liquified lesion volume increased as power was raised, without a thermal rise. For brain unit sonications, a power setting of 600 W and ultrashort sonications (burst length between 0·1 and 1·0 ms) resulted in liquefaction efficacy above 50%, while longer burst duration yielded lower efficacy. These results demonstrate the feasibility of obtaining reproducible, rapid, efficient, and accurate blood clot lysis using the magnetic resonance-guided focused ultrasound system. Further in vivo studies are needed to validate the feasibility of magnetic resonance-guided focused ultrasound as a treatment modality for intracranial hemorrhage. © 2013 The Authors. International Journal of

  7. Volumetric feedback ablation of uterine fibroids using magnetic resonance-guided high intensity focused ultrasound therapy.

    Science.gov (United States)

    Voogt, M J; Trillaud, H; Kim, Y S; Mali, W P Th M; Barkhausen, J; Bartels, L W; Deckers, R; Frulio, N; Rhim, H; Lim, H K; Eckey, T; Nieminen, H J; Mougenot, C; Keserci, B; Soini, J; Vaara, T; Köhler, M O; Sokka, S; van den Bosch, Maurice A A J

    2012-02-01

    The purpose of this prospective multicenter study was to assess the safety and technical feasibility of volumetric Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) ablation for treatment of patients with symptomatic uterine fibroids. Thirty-three patients with 36 fibroids were treated with volumetric MR-HIFU ablation. Treatment capability and technical feasibility were assessed by comparison of the Non-Perfused Volumes (NPVs) with MR thermal dose predicted treatment volumes. Safety was determined by evaluation of complications or adverse events and unintended lesions. Secondary endpoints were pain and discomfort scores, recovery time and length of hospital stay. The mean NPV calculated as a percentage of the total fibroid volume was 21.7%. Correlation between the predicted treatment volumes and NPVs was found to be very strong, with a correlation coefficient r of 0.87. All patients tolerated the treatment well and were treated on an outpatient basis. No serious adverse events were reported and recovery time to normal activities was 2.3 ± 1.8 days. This prospective multicenter study proved that volumetric MR-HIFU is safe and technically feasible for the treatment of symptomatic uterine fibroids. • Magnetic-resonance-guided high intensity focused ultrasound allows non-invasive treatment of uterine fibroids. • Volumetric feedback ablation is a novel technology that allows larger treatment volumes • MR-guided ultrasound ablation of uterine fibroids appears safe using volumetric feedback.

  8. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation of liver tumours.

    Science.gov (United States)

    Wijlemans, J W; Bartels, L W; Deckers, R; Ries, M; Mali, W P Th M; Moonen, C T W; van den Bosch, M A A J

    2012-09-28

    Recent decades have seen a paradigm shift in the treatment of liver tumours from invasive surgical procedures to minimally invasive image-guided ablation techniques. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a novel, completely non-invasive ablation technique that has the potential to change the field of liver tumour ablation. The image guidance, using MR imaging and MR temperature mapping, provides excellent planning images and real-time temperature information during the ablation procedure. However, before clinical implementation of MR-HIFU for liver tumour ablation is feasible, several organ-specific challenges have to be addressed. In this review we discuss the MR-HIFU ablation technique, the liver-specific challenges for MR-HIFU tumour ablation, and the proposed solutions for clinical translation.

  9. Acoustic characterization of Thiel liver for magnetic resonance-guided focused ultrasound treatment.

    Science.gov (United States)

    Karakitsios, Ioannis; Joy, Joyce; Mihcin, Senay; Melzer, Andreas

    2017-04-01

    The purpose of this work was to measure the essential acoustic parameters, i.e., acoustic impedance, reflection coefficient, attenuation coefficient, of Thiel embalmed human and animal liver. The Thiel embalmed tissue can be a promising, pre-clinical model to study liver treatment with Magnetic Resonance-guided Focused Ultrasound (MRgFUS). Using a single-element transducer and the contact pulse-echo method, the acoustic parameters, i.e., acoustic impedance, reflection coefficient and attenuation coefficient of Thiel embalmed human and animal liver were measured. The Thiel embalmed livers had higher impedance, similar reflection and lower attenuation compared to the fresh tissue. Embalming liver with Thiel fluid affects its acoustic properties. During MRgFUS sonication of a Thiel organ, more focused ultrasound (FUS) will be backscattered by the organ, and higher acoustic powers are required to reach coagulation levels (temperatures >56 °C).

  10. Magnetic resonance imaging-guided focused ultrasound to increase localized blood-spinal cord barrier permeability.

    Science.gov (United States)

    Payne, Allison H; Hawryluk, Gregory W; Anzai, Yoshimi; Odéen, Henrik; Ostlie, Megan A; Reichert, Ethan C; Stump, Amanda J; Minoshima, Satoshi; Cross, Donna J

    2017-12-01

    Spinal cord injury (SCI) affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this issue, we used magnetic resonance imaging-guided focused ultrasound (MRgFUS) as a non-invasive approach to increase permeability in the blood-spinal cord barrier (BSCB). We hypothesize that localized, controlled sonoporation of the BSCB by MRgFUS will aid delivery of therapeutics to the injury. Here, we report our preliminary findings for the ability of MRgFUS to increase BSCB permeability in the thoracic spinal cord of a normal rat model. First, an excised portion of normal rat spinal column was used to characterize the acoustic field and to estimate the insertion losses that could be expected in an MRgFUS blood spinal cord barrier opening. Then, in normal rats, MRgFUS was applied in combination with intravenously administered microbubbles to the spinal cord region. Permeability of the BSCB was indicated as signal enhancement by contrast administered prior to T1-weighted magnetic resonance imaging and verified by Evans blue dye. Neurological testing using the Basso, Beattie, and Breshnahan scale and the ladder walk was normal in 8 of 10 rats tested. Two rats showed minor impairment indicating need for further refinement of parameters. No gross tissue damage was evident by histology. In this study, we have opened successfully the blood spinal cord barrier in the thoracic region of the normal rat spine using magnetic resonance-guided focused ultrasound combined with microbubbles.

  11. Functional Neurosurgery in the Human Thalamus by Transcranial Magnetic Resonance Guided Focused Ultrasound

    Science.gov (United States)

    Werner, Beat; Morel, Anne; Jeanmonod, Daniel; Martin, Ernst

    2009-04-01

    Potential applications of Transcranial Magnetic Resonance guided Focused Ultrasound (TcMRgFUS) include treatment of functional brain disorders, such as Parkinson's disease, dystonia and tremor, neurogenic pain and tinnitus, neuropsychiatric disorders and epilepsy. In this study we demonstrate the feasibility of non-invasive TcMRgFUS ablation of clinically well established targets in the human thalamus that are currently accessed stereotactically by interventional strategies based on the concept of the thalamocortical dysrhythmia (TCD). Thermal hotspots suitable for clinical intervention were created successfully in anatomical preparations of human ex-vivo heads under pseudo clinical conditions. The hotspots could be positioned at the target locations as needed and local energy deposition was sufficient to create tissue ablation. Numerical simulations based on these experimental data predict that the acoustic energy needed to create ablative lesions in-vivo will be within limits that can safely applied.

  12. Magnetic Resonance Imaging-Guided Focused Ultrasound Surgery for the Treatment of Symptomatic Uterine Fibroids

    Directory of Open Access Journals (Sweden)

    Laura Geraci

    2017-01-01

    Full Text Available Uterine fibroids, the most common benign tumor in women of childbearing age, may cause symptoms including pelvic pain, menorrhagia, dysmenorrhea, pressure, urinary symptoms, and infertility. Various approaches are available to treat symptomatic uterine fibroids. Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS represents a recently introduced noninvasive safe and effective technique that can be performed without general anesthesia, in an outpatient setting. We review the principles of MRgFUS, describing patient selection criteria for the treatments performed at our center and we present a series of five selected patients with symptomatic uterine fibroids treated with this not yet widely known technique, showing its efficacy in symptom improvement and fibroid volume reduction.

  13. Dynamic T2-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    Science.gov (United States)

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M.

    2012-11-01

    Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1°C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T2, since T2 increases linearly in fat during heating. T2-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T2. Calibration of T2-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T2 and temperature with a thermocouple. A positive T2 temperature dependence in bone marrow of 20 ms/°C was observed. Dynamic T2-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

  14. Alternatives to hysterectomy: focus on global endometrial ablation, uterine fibroid embolization, and magnetic resonance-guided focused ultrasound.

    Science.gov (United States)

    Stovall, Dale W

    2011-04-01

    The aim of this study was to inform the clinician of alternatives to hysterectomy through a critical evaluation of three treatment options: global endometrial ablation, uterine fibroid embolization, and magnetic resonance-guided focused ultrasound. Studies published in English-language, peer-reviewed journals were systematically searched using Cochrane and Medline. Keywords used included "alternatives to hysterectomy," "endometrial ablation," "uterine fibroid embolization," "uterine artery embolization," and "focused ultrasound." Articles meeting the inclusion criteria were reviewed and analyzed for themes and similarities. All three alternative methods of treatment reviewed are currently approved for use in the United States and abroad. In fact, five different global endometrial ablation devices are approved by the Food and Drug Administration for treatment of menorrhagia. Patient satisfaction scores after endometrial ablation are high (90%-95%), but amenorrhea rates are much lower (15%-60%). Data from randomized trials demonstrate that uterine fibroid embolization results in a shorter hospital stay and quicker return to work as compared with abdominal hysterectomy for leiomyomas, but after embolization, up to 20% of women need a second procedure. Ex-ablative therapy of leiomyomas with focused ultrasound is the newest of the three methods. It has a special set of patient selection criteria and is only available at less than 20 medical centers in the United States. Leiomyoma symptom relief after focused ultrasound therapy at 1 year post-procedure is high (85%-95%). There are many effective alternatives to hysterectomy in women with menorrhagia and/or symptomatic leiomyomas. However, because these procedures are performed by individuals from different subspecialists, primarily gynecologists and interventional radiologists, clinicians must consider using a multidisciplinary approach to find the best procedure for a given patient. There are no randomized trials

  15. Early evaluation of magnetic resonance imaging guided focused ultrasound sonication in the treatment of uterine fibroids

    Directory of Open Access Journals (Sweden)

    Y Himabindu

    2014-01-01

    Full Text Available Background & objectives: Uterine leiomyomas (fibroids are common cause of morbidity in women of reproductive age group. High intensity focused ultrasound with the imaging guidance of magnetic resonance imaging (MRI known as magnetic resonance guided focused ultrasound sonication (MRgFUS is now available. However, there are no available studies with this non invasive modality of treatment in Indian subjects. The objective of this study was to determine the safety and clinical efficacy of MRgFUS in the treatment of uterine fibroids. Methods: This prospective study included 32 consecutive women with clinically symptomatic uterine fibroids who were treated with MRgFUS from February 2011 to October 2011. Pre and post treatment symptom severity scores (SSS were assessed at the time of enrolment and at one, three and six months follow up using a validated uterine fibroid symptom - quality of life questionnaire (UFS-QOL. Pre and post treatment fibroid volumes were compared immediately after treatment and at six months follow up using contrast enhanced MRI scan. Non perfused volume (NPV ratios were calculated and correlated with fibroid volume reductions immediately after the treatment and at the end of six months follow up. Results: This procedure was well tolerated by the patients and procedure related adverse effects were non significant. Significant reductions in SSS were seen at one, three and six month intervals after the treatment (P<0.01. Significant reductions were noticed in fibroid volumes at six months follow up compared to pretreatment fibroid volumes (P<0.01. Significant positive correlations were observed between NPV ratios and reduction in fibroid volumes at six months follow-up (r=0.659, P<0.01. Interpretation & conclusions: MRgFUS is relatively a safe and effective non invasive treatment modality for treating uterine fibroids in selected patients. Its long term efficacy is yet to be tested and compared with other available minimally

  16. Volumetric feedback ablation of uterine fibroids using magnetic resonance-guided high intensity focused ultrasound therapy

    Energy Technology Data Exchange (ETDEWEB)

    Voogt, M.J.; Mali, W.P.T.M.; Bosch, Maurice A.A.J. van den [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Trillaud, H.; Frulio, N. [Hospital St. Andre, Department of Radiology, Bordeaux (France); Kim, Y.S.; Rhim, H.; Lim, H.K. [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Barkhausen, J.; Eckey, T. [University Hospital Schleswig-Holstein, Department of Radiology, Luebeck (Germany); Bartels, L.W.; Deckers, R. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands); Nieminen, H.J.; Soini, J.; Vaara, T.; Koehler, M.O. [Philips Healthcare, Vantaa (Finland); Mougenot, C. [Philips Healthcare, Toronto (Canada); Keserci, B. [Philips Healthcare, Seoul (Korea, Republic of); Sokka, S. [Philips Healthcare, Andover, MA (United States)

    2012-02-15

    The purpose of this prospective multicenter study was to assess the safety and technical feasibility of volumetric Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) ablation for treatment of patients with symptomatic uterine fibroids. Thirty-three patients with 36 fibroids were treated with volumetric MR-HIFU ablation. Treatment capability and technical feasibility were assessed by comparison of the Non-Perfused Volumes (NPVs) with MR thermal dose predicted treatment volumes. Safety was determined by evaluation of complications or adverse events and unintended lesions. Secondary endpoints were pain and discomfort scores, recovery time and length of hospital stay. The mean NPV calculated as a percentage of the total fibroid volume was 21.7%. Correlation between the predicted treatment volumes and NPVs was found to be very strong, with a correlation coefficient r of 0.87. All patients tolerated the treatment well and were treated on an outpatient basis. No serious adverse events were reported and recovery time to normal activities was 2.3 {+-} 1.8 days. This prospective multicenter study proved that volumetric MR-HIFU is safe and technically feasible for the treatment of symptomatic uterine fibroids. (orig.)

  17. Ultrasound beam simulation for magnetic resonance-guided focused ultrasound surgery

    Science.gov (United States)

    Vyas, Urvi

    2011-12-01

    Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is a noninvasive means of causing selective tissue necrosis using high-power ultrasound and MR temperature imaging. Inhomogeneities in the medium of propagation can cause significant distortion of the ultrasound beam, resulting in changes in focal-zone amplitude, location and shape. Current ultrasound beam simulation techniques are either only applicable to homogeneous media or are relatively slow in calculating power deposition patterns in inhomogeneous media. Further, these techniques use table-value estimates of the acoustic parameters for predicting ultrasound beam propagation in inhomogeneous media, resulting in at best an approximate power deposition pattern. This work improves numerical analysis of ultrasound beam propagation by developing techniques for: 1) fast, accurate predictions of ultrasound beam propagation in inhomogeneous media, 2) noninvasive estimation of acoustic parameters (speed of sound and attenuation coefficient) of tissue types present in inhomogeneous media, 3) noninvasive determination of changes in tissue acoustic properties due to treatment. These beam simulation techniques utilizing subject-specific tissue parameters will rapidly predict power deposition patterns in real patient geometries and estimate changes in tissue acoustic parameters during treatment, leading to treatment-responsive patient-specific treatment plans that will improve the safety, efficacy and effectiveness of MRgFUS.

  18. Histopathology of breast cancer after magnetic resonance-guided high-intensity focused ultrasound and radiofrequency ablation

    NARCIS (Netherlands)

    Knuttel, Floor; Waaijer, Laurien; Merckel, LG; van den Bosch, Maurice A A J; Witkamp, Arjen J.; Deckers, Roel; van Diest, Paul J.

    AIMS: Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation and radiofrequency ablation (RFA) are being researched as possible substitutes for surgery in breast cancer patients. The histopathological appearance of ablated tissue has not been studied in great detail. This

  19. Effects of magnetic resonance-guided high-intensity focused ultrasound ablation on bone mechanical properties and modeling

    NARCIS (Netherlands)

    Yeo, Sin Yuin; Arias Moreno, Andrés J; van Rietbergen, Bert; Ter Hoeve, Natalie D; van Diest, Paul J; Grüll, Holger

    2015-01-01

    BACKGROUND: Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a promising technique for palliative treatment of bone pain. In this study, the effects of MR-HIFU ablation on bone mechanics and modeling were investigated. METHODS: A total of 12 healthy rat femurs were ablated

  20. A long arm for ultrasound: a combined robotic focused ultrasound setup for magnetic resonance-guided focused ultrasound surgery.

    Science.gov (United States)

    Krafft, Axel J; Jenne, Jürgen W; Maier, Florian; Stafford, R Jason; Huber, Peter E; Semmler, Wolfhard; Bock, Michael

    2010-05-01

    Focused ultrasound surgery (FUS) is a highly precise noninvasive procedure to ablate pathogenic tissue. FUS therapy is often combined with magnetic resonance (MR) imaging as MR imaging offers excellent target identification and allows for continuous monitoring of FUS induced temperature changes. As the dimensions of the ultrasound (US) focus are typically much smaller than the targeted volume, multiple sonications and focus repositioning are interleaved to scan the focus over the target volume. Focal scanning can be achieved electronically by using phased-array US transducers or mechanically by using dedicated mechanical actuators. In this study, the authors propose and evaluate the precision of a combined robotic FUS setup to overcome some of the limitations of the existing MRgFUS systems. Such systems are typically integrated into the patient table of the MR scanner and thus only provide an application of the US wave within a limited spatial range from below the patient. The fully MR-compatible robotic assistance system InnoMotion (InnoMedic GmbH, Herxheim, Germany) was originally designed for MR-guided interventions with needles. It offers five pneumatically driven degrees of freedom and can be moved over a wide range within the bore of the magnet. In this work, the robotic system was combined with a fixed-focus US transducer (frequency: 1.7 MHz; focal length: 68 mm, and numerical aperture: 0.44) that was integrated into a dedicated, in-house developed treatment unit for FUS application. A series of MR-guided focal scanning procedures was performed in a polyacrylamide-egg white gel phantom to assess the positioning accuracy of the combined FUS setup. In animal experiments with a 3-month-old domestic pig, the system's potential and suitability for MRgFUS was tested. In phantom experiments, a total targeting precision of about 3 mm was found, which is comparable to that of the existing MRgFUS systems. Focus positioning could be performed within a few seconds

  1. Magnetic resonance-guided focused ultrasound surgery for treatment of painful osseous metastases

    Science.gov (United States)

    Hurwitz, Mark; Machtinger, Ronit; Fennessy, Fiona

    2011-03-01

    Magnetic resonance guided focused ultrasound surgery (MRgFUS) is an emerging technology that can non-invasively heat and ablate targeted tissue utilizing ultrasound energy. Use of MR imaging for treatment guidance provides several key advantages over more widely used ultrasound guidance for focused ultrasound ablation. MR allows for precise targeting, detailed beam path visualization, real time non-invasive temperature measurement, and treatment feedback to ensure therapeutic goals are achieved. In the realm of oncology, management of painful bone metastases is a common and daunting clinical problem. The Insightec ExAblate System has been shown in phase I/II trials for treatment of bone metastases to have an excellent safety profile and high rates of pain response. An international multi-center phase III trial for patients with painful bone metastases or multiple myeloma who are not candidates for radiation therapy is currently open. Patients are randomized 3:1 to MRgFUS or sham treatment with crossover to study treatment allowed for sham failures. The primary study endpoint is assessment of pain control over 3 months following treatment. In addition safety, quality of life, cost effectiveness analysis, and patient perceived clinical benefit are also being assessed. Details of the MRgFUS system, technical and clinical therapeutic parameters, use of real time non-invasive MR thermometry, and examples of patient treatments with use of MRgFUS to treat bone metastases will be discussed. New directions in use of MRgFUS including an update on development of a new mobile applicator and integration of MRgFUS in multimodality oncologic care will also be presented.

  2. Efficacy of Magnetic Resonance-guided Focused Ultrasound Surgery for Bone Metastases Pain Palliation

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    Kawasaki, Motohiro; Nanba, Hirofumi; Kato, Tomonari; Tani, Toshikazu; Ushida, Takahiro

    2011-09-01

    Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is a novel treatment method that achieves non-invasive thermal ablation by focusing many ultrasound waves on a target tissue with real-time monitoring of the location and temperature of the target during the procedure. We investigated the palliative effect on pain and safety of MRgFUS in painful bone metastases. Six patients (mean age, 65.8 years) who met eligibility criteria for the clinical study approved by our Institutional Ethics Committee based on the cooperative protocol were treated with MRgFUS. Targeted sites included the sacrum (n = 1), ilium (n = 2), scapula (n = 2), and femur (n = 1). The mean follow-up period was 9.2 months. All procedures were performed as a single-session treatment using the treatment system that is integrated into the patient table of a magnetic resonance image (MRI) scanner. Endpoints were change in the intensity of pain due to bone metastases from before to after the treatment, as measured on a numerical rating scale, pain interference with daily activities as determined by the Brief pain inventory (BPI), change in images, and safety. Pain relief was obtained in all patients early after treatment, with a reduction in the mean pain score from 6.0±1.3 at baseline to 1.2±1.0 at the end of follow-up as well as in pain interference with daily activities. The mean time required for a single-session treatment was 83.7±37.0 min, with a mean number of sonications required of 13.3±3.7 and mean energy applied of 846.4±273.5 J. No significant growth of tumors was observed, nor were there treatment-related adverse events. These results suggest that MRgFUS has a non-invasive palliative effect on the localized pain in patients with bone metastasis. MRgFUS could become an option in treatment strategies for painful bone metastases in the future.

  3. Magnetic Resonance-Guided High-Intensity Focused Ultrasound Ablation of Osteoid Osteoma: A Case Series Report.

    Science.gov (United States)

    Rovella, Marcello S; Martins, Guilherme L P; Cavalcanti, Conrado F A; Bor-Seng-Shu, Edson; Camargo, Olavo P; Cerri, Giovanni G; Menezes, Marcos R

    2016-04-01

    Osteoid osteoma is painful benign tumor. The aim of this study was to report our initial experience using magnetic resonance-guided focused ultrasound to treat osteoid osteomas. This retrospective single-center study included four patients treated with magnetic resonance-guided focused ultrasound. They presented with severe pain with reduced quality of life and a poor response to clinical treatment. The pre- and post-treatment evaluation comprised computed tomography and magnetic resonance imaging and focused on quality of life and the impact of pain on daily activities. After treatment, three patients had complete pain resolution with no recurrence. One patient had a recurrence of symptoms after 2 wk and underwent a new successful treatment with increased energy levels. On average, 13 sonications were administered (8-18 sonications/treatment) with an average energy of 2,003 J (range: 1,063-3,522 J). Magnetic resonance-guided focused ultrasound appears to be a feasible, tolerable and effective treatment in selected patients with osteoid osteomas. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  4. Magnetic Resonance-guided Focused Ultrasound Treatment for Uterine Fibroids: First Study in Indian Women

    Directory of Open Access Journals (Sweden)

    Shrinivas B Desai

    2012-01-01

    Full Text Available Objectives: To study the results of magnetic resonance-guided focused ultrasound surgery (MRgFUS treatment carried out on Indian patients in our Hospital. Materials and Methods: Fifty Indian women (mean age = 36.2 ± 8.3 years were treated for fibroids as outpatients using the ExAblate MRgFUS system (InSightec. Non-perfused volumes (NPVs were measured immediately after treatment to calculate the treatment outcomes. A validated symptom-specific questionnaire to record their symptoms prior to treatment and six months following treatment was completed by patients. The size of the fibroids was measured on the day of the treatment and during the 6-month checkup to calculate shrinkage. Adverse events during and following treatment were recorded and monitored. Results: The average NPV ratio measured after the treatment was 88% ± 6%, indicative of high ablated fibroid tissue. Prior to treatment, the mean Symptoms Severity Score was 56.9 ± 4.8 (n = 50, which is indicative of highly symptomatic patients. Six months following treatment, there was an average fibroid shrinkage of 30% ± 11%, and a significant decrease in the mean score to 28.6 ± 6.0 (n = 50 (P < 0.001. There were no reports of serious or unexpected adverse events at any point during treatment or during the follow-up period from any of the 50 women treated in the current study. Conclusions: The current results obtained after 6 months of treatment corroborated previous data on the safety and efficacy of MRgFUS for treating uterine fibroids. This is the first publication that provides such data for a large cohort of Indian women.

  5. Renal ablation using magnetic resonance-guided high intensity focused ultrasound: Magnetic resonance imaging and histopathology assessment

    Science.gov (United States)

    Saeed, Maythem; Krug, Roland; Do, Loi; Hetts, Steven W; Wilson, Mark W

    2016-01-01

    AIM: To use magnetic resonance-guided high intensity focused ultrasound (MRg-HIFU), magnetic resonance imaging (MRI) and histopathology for noninvasively ablating, quantifying and characterizing ablated renal tissue. METHODS: Six anesthetized/mechanically-ventilated pigs underwent single/double renal sonication (n = 24) using a 3T-MRg-HIFU (1.1 MHz frequency and 3000J-4400J energies). T2-weighted fast spin echo (T2-W), perfusion saturation recovery gradient echo and contrast enhanced (CE) T1-weighted (T1-W) sequences were used for treatment planning, temperature monitoring, lesion visualization, characterization and quantification, respectively. Histopathology was conducted in excised kidneys to quantify and characterize cellular and vascular changes. Paired Student’s t-test was used and a P-value < 0.05 was considered statistically significant. RESULTS: Ablated renal parenchyma could not be differentiated from normal parenchyma on T2-W or non-CE T1-W sequences. Ablated renal lesions were visible as hypoenhanced regions on perfusion and CE T1-W MRI sequences, suggesting perfusion deficits and necrosis. Volumes of ablated parenchyma on CE T1-W images in vivo (0.12-0.36 cm3 for single sonication 3000J, 0.50-0.84 cm3, for double 3000J, 0.75-0.78 cm3 for single 4400J and 0.12-2.65 cm3 for double 4400J) and at postmortem (0.23-0.52 cm3, 0.25-0.82 cm3, 0.45-0.68 cm3 and 0.29-1.80 cm3, respectively) were comparable. The ablated volumes on 3000J and 4400J double sonication were significantly larger than single (P < 0.01), thus, the volume and depth of ablated tissue depends on the applied energy and number of sonication. Macroscopic and microscopic examinations confirmed the locations and presence of coagulation necrosis, vascular damage and interstitial hemorrhage, respectively. CONCLUSION: Contrast enhanced MRI provides assessment of MRg-HIFU renal ablation. Histopathology demonstrated coagulation necrosis, vascular damage and confirmed the volume of damage seen on MRI

  6. The emerging role of transcranial magnetic resonance imaging-guided focused ultrasound in functional neurosurgery.

    Science.gov (United States)

    Weintraub, David; Elias, W Jeffrey

    2017-01-01

    To review the emerging role of transcranial MR-guided focused ultrasound as a treatment and research modality for functional neurological disorders, we summarize recent clinical and preclinical studies. Clinical trials have investigated the safety and efficacy of thermal lesions created by transcranial, high-intensity focused ultrasound. Preclinical work has additionally investigated the ability to disrupt the blood-brain barrier and to produce reversible neuromodulation with focused ultrasound utilizing lower intensities. We discuss ongoing trials and future avenues of investigation. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

  7. Magnetic resonance-guided focused ultrasound: a new technology for clinical neurosciences.

    Science.gov (United States)

    Jolesz, Ferenc A; McDannold, Nathan J

    2014-02-01

    Transcranial MRI-guided focused ultrasound (TcMRgFUS) is an old idea but a new technology that may change the entire clinical field of the neurosciences. TcMRgFUS has no cumulative effect, and it is applicable for repeatable treatments, controlled by real-time dosimetry, and capable of immediate tissue destruction. Most importantly, it has extremely accurate targeting and constant monitoring. It is potentially more precise than proton beam therapy and definitely more cost effective. Neuro-oncology may be the most promising area of future TcMRgFUS applications. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Magnetic resonance image-guided versus ultrasound-guided high-intensity focused ultrasound in the treatment of breast cancer

    Science.gov (United States)

    Li, Sheng; Wu, Pei-Hong

    2013-01-01

    Image-guided high-intensity focused ultrasound (HIFU) has been used for more than ten years, primarily in the treatment of liver and prostate cancers. HIFU has the advantages of precise cancer ablation and excellent protection of healthy tissue. Breast cancer is a common cancer in women. HIFU therapy, in combination with other therapies, has the potential to improve both oncologic and cosmetic outcomes for breast cancer patients by providing a curative therapy that conserves mammary shape. Currently, HIFU therapy is not commonly used in breast cancer treatment, and efforts to promote the application of HIFU is expected. In this article, we compare different image-guided models for HIFU and reviewed the status, drawbacks, and potential of HIFU therapy for breast cancer. PMID:23237221

  9. Open-source, small-animal magnetic resonance-guided focused ultrasound system.

    Science.gov (United States)

    Poorman, Megan E; Chaplin, Vandiver L; Wilkens, Ken; Dockery, Mary D; Giorgio, Todd D; Grissom, William A; Caskey, Charles F

    2016-01-01

    MR-guided focused ultrasound or high-intensity focused ultrasound (MRgFUS/MRgHIFU) is a non-invasive therapeutic modality with many potential applications in areas such as cancer therapy, drug delivery, and blood-brain barrier opening. However, the large financial costs involved in developing preclinical MRgFUS systems represent a barrier to research groups interested in developing new techniques and applications. We aim to mitigate these challenges by detailing a validated, open-source preclinical MRgFUS system capable of delivering thermal and mechanical FUS in a quantifiable and repeatable manner under real-time MRI guidance. A hardware and software package was developed that includes closed-loop feedback controlled thermometry code and CAD drawings for a therapy table designed for a preclinical MRI scanner. For thermal treatments, the modular software uses a proportional integral derivative controller to maintain a precise focal temperature rise in the target given input from MR phase images obtained concurrently. The software computes the required voltage output and transmits it to a FUS transducer that is embedded in the delivery table within the magnet bore. The delivery table holds the FUS transducer, a small animal and its monitoring equipment, and a transmit/receive RF coil. The transducer is coupled to the animal via a water bath and is translatable in two dimensions from outside the magnet. The transducer is driven by a waveform generator and amplifier controlled by real-time software in Matlab. MR acoustic radiation force imaging is also implemented to confirm the position of the focus for mechanical and thermal treatments. The system was validated in tissue-mimicking phantoms and in vivo during murine tumor hyperthermia treatments. Sonications were successfully controlled over a range of temperatures and thermal doses for up to 20 min with minimal temperature overshoot. MR thermometry was validated with an optical temperature probe, and focus

  10. Segmentation Method for Magnetic Resonance-Guided High-Intensity Focused Ultrasound Therapy Planning

    Directory of Open Access Journals (Sweden)

    A. Vargas-Olivares

    2017-01-01

    Full Text Available High-intensity focused ultrasound (HIFU is a minimally invasive therapy modality in which ultrasound beams are concentrated at a focal region, producing a rise of temperature and selective ablation within the focal volume and leaving surrounding tissues intact. HIFU has been proposed for the safe ablation of both malignant and benign tissues and as an agent for drug delivery. Magnetic resonance imaging (MRI has been proposed as guidance and monitoring method for the therapy. The identification of regions of interest is a crucial procedure in HIFU therapy planning. This procedure is performed in the MR images. The purpose of the present research work is to implement a time-efficient and functional segmentation scheme, based on the watershed segmentation algorithm, for the MR images used for the HIFU therapy planning. The achievement of a segmentation process with functional results is feasible, but preliminary image processing steps are required in order to define the markers for the segmentation algorithm. Moreover, the segmentation scheme is applied in parallel to an MR image data set through the use of a thread pool, achieving a near real-time execution and making a contribution to solve the time-consuming problem of the HIFU therapy planning.

  11. Magnetic resonance-guided shielding of prefocal acoustic obstacles in focused ultrasound therapy: application to intercostal ablation in liver.

    Science.gov (United States)

    Salomir, Rares; Petrusca, Lorena; Auboiroux, Vincent; Muller, Arnaud; Vargas, Maria-Isabel; Morel, Denis R; Goget, Thomas; Breguet, Romain; Terraz, Sylvain; Hopple, Jerry; Montet, Xavier; Becker, Christoph D; Viallon, Magalie

    2013-06-01

    The treatment of liver cancer is a major public health issue because the liver is a frequent site for both primary and secondary tumors. Rib heating represents a major obstacle for the application of extracorporeal focused ultrasound to liver ablation. Magnetic resonance (MR)-guided external shielding of acoustic obstacles (eg, the ribs) was investigated here to avoid unwanted prefocal energy deposition in the pathway of the focused ultrasound beam. Ex vivo and in vivo (7 female sheep) experiments were performed in this study. Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) was performed using a randomized 256-element phased-array transducer (f∼1 MHz) and a 3-T whole-body clinical MR scanner. A physical mask was inserted in the prefocal beam pathway, external to the body, to block the energy normally targeted on the ribs. The effectiveness of the reflecting material was investigated by characterizing the efficacy of high-intensity focused ultrasound beam reflection and scattering on its surface using Schlieren interferometry. Before high-intensity focused ultrasound sonication, the alignment of the protectors with the conical projections of the ribs was required and achieved in multiple steps using the embedded graphical tools of the MR scanner. Multiplanar near real-time MR thermometry (proton resonance frequency shift method) enabled the simultaneous visualization of the local temperature increase at the focal point and around the exposed ribs. The beam defocusing due to the shielding was evaluated from the MR acoustic radiation force impulse imaging data. Both MR thermometry (performed with hard absorber positioned behind a full-aperture blocking shield) and Schlieren interferometry indicated a very good energy barrier of the shielding material. The specific temperature contrast between rib surface (spatial average) and focus, calculated at the end point of the MRgHIFU sonication, with protectors vs no protectors, indicated an important

  12. Targeted Vessel Ablation for More Efficient Magnetic Resonance-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Voogt, Marianne J., E-mail: m.voogt@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands); Stralen, Marijn van [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Ikink, Marlijne E. [University Medical Center Utrecht, Department of Radiology (Netherlands); Deckers, Roel; Vincken, Koen L.; Bartels, Lambertus W. [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Mali, Willem P. Th. M.; Bosch, Maurice A. A. J. van den [University Medical Center Utrecht, Department of Radiology (Netherlands)

    2012-10-15

    Purpose: To report the first clinical experience with targeted vessel ablation during magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) treatment of symptomatic uterine fibroids. Methods: Pretreatment T1-weighted contrast-enhanced magnetic resonance angiography was used to create a detailed map of the uterine arteries and feeding branches to the fibroids. A three-dimensional overlay of the magnetic resonance angiography images was registered on 3D T2-weighted pretreatment imaging data. Treatment was focused primarily on locations where supplying vessels entered the fibroid. Patients were followed 6 months after treatment with a questionnaire to assess symptoms and quality of life (Uterine Fibroid Symptom and Quality of Life) and magnetic resonance imaging to quantify shrinkage of fibroid volumes. Results: In two patients, three fibroids were treated with targeted vessel ablation during MR-HIFU. The treatments resulted in almost total fibroid devascularization with nonperfused volume to total fibroid volume ratios of 84, 68, and 86%, respectively, of treated fibroids. The predicted ablated volumes during MR-HIFU in patients 1 and 2 were 45, 40, and 82 ml, respectively, while the nonperfused volumes determined immediately after treatment were 195, 92, and 190 ml respectively, which is 4.3 (patient 1) and 2.3 (patient 2) times higher than expected based on the thermal dose distribution. Fibroid-related symptoms reduced after treatment, and quality of life improved. Fibroid volume reduction ranged 31-59% at 6 months after treatment. Conclusion: Targeted vessel ablation during MR-HIFU allowed nearly complete fibroid ablation in both patients. This technique may enhance the use of MR-HIFU for fibroid treatment in clinical practice.

  13. Successful Magnetic Resonance Imaging-Guided Focused Ultrasound Surgery for Recurrent Uterine Fibroid Previously Treated with Uterine Artery Embolization

    Directory of Open Access Journals (Sweden)

    Sang-Wook Yoon

    2010-01-01

    Full Text Available A 45-year-old premenopausal woman was referred to our clinic due to recurring symptoms of uterine fibroids, nine years after a uterine artery embolization (UAE. At the time of screening, the patient presented with bilateral impairment and narrowing of the uterine arteries, which increased the risk of arterial perforation during repeated UAE procedures. The patient was subsequently referred for magnetic resonance imaging-guided focused ultrasound surgery (MRgFUS treatment. Following the treatment, the patient experienced a significant improvement in symptoms (symptom severity score was reduced from 47 to 12 by 1 year post-treatment. MR images at 3 months showed a 49% decrease in fibroid volume. There were no adverse events during the treatment or the follow-up period. This case suggests that MRgFUS can be an effective treatment option for patients with recurrent fibroids following previous UAE treatment.

  14. Dynamic T{sub 2}-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    Energy Technology Data Exchange (ETDEWEB)

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M. [Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Philips Healthcare Canada, Markham, ON, L6C 2S3 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Department of Applied Mathematics, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada)

    2012-11-28

    Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1 Degree-Sign C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T{sub 2}, since T{sub 2} increases linearly in fat during heating. T{sub 2}-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T{sub 2}. Calibration of T{sub 2}-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T{sub 2} and temperature with a thermocouple. A positive T{sub 2} temperature dependence in bone marrow of 20 ms/ Degree-Sign C was observed. Dynamic T{sub 2}-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

  15. Factors associated with successful magnetic resonance-guided focused ultrasound treatment: efficiency of acoustic energy delivery through the skull.

    Science.gov (United States)

    Chang, Won Seok; Jung, Hyun Ho; Zadicario, Eyal; Rachmilevitch, Itay; Tlusty, Tal; Vitek, Shuki; Chang, Jin Woo

    2016-02-01

    Magnetic resonance-guided focused ultrasound surgery (MRgFUS) was recently introduced as treatment for movement disorders such as essential tremor and advanced Parkinson's disease (PD). Although deep brain target lesions are successfully generated in most patients, the target area temperature fails to increase in some cases. The skull is one of the greatest barriers to ultrasonic energy transmission. The authors analyzed the skull-related factors that may have prevented an increase in target area temperatures in patients who underwent MRgFUS. The authors retrospectively reviewed data from clinical trials that involved MRgFUS for essential tremor, idiopathic PD, and obsessive-compulsive disorder. Data from 25 patients were included. The relationships between the maximal temperature during treatment and other factors, including sex, age, skull area of the sonication field, number of elements used, skull volume of the sonication field, and skull density ratio (SDR), were determined. Among the various factors, skull volume and SDR exhibited relationships with the maximum temperature. Skull volume was negatively correlated with maximal temperature (p = 0.023, r(2) = 0.206, y = 64.156 - 0.028x, whereas SDR was positively correlated with maximal temperature (p = 0.009, r(2) = 0.263, y = 49.643 + 11.832x). The other factors correlate with the maximal temperature, although some factors showed a tendency to correlate. Some skull-related factors correlated with the maximal target area temperature. Although the number of patients in the present study was relatively small, the results offer information that could guide the selection of MRgFUS candidates.

  16. Pregnancy outcome after magnetic resonance-guided focused ultrasound surgery (MRgFUS) for conservative treatment of uterine fibroids.

    Science.gov (United States)

    Rabinovici, Jaron; David, Matthias; Fukunishi, Hidenobu; Morita, Yutaka; Gostout, Bobbie S; Stewart, Elizabeth A

    2010-01-01

    To report all pregnancies to date after magnetic resonance-guided focused ultrasound surgery (MRgFUS) for the conservative treatment of clinically significant uterine fibroids. Prospective registry of all known pregnancies occurring after MRgFUS maintained by the device manufacturer and reported to the Food and Drug Administration. World experience of pregnancies after treatment with reports from 13 sites in seven countries. Fifty-one reproductive-age women with uterine leiomyomas. Women underwent MRgFUS treatment for symptomatic uterine leiomyomas before this report. Pregnancy outcomes and complications. Fifty-four pregnancies in 51 women have occurred after MRgFUS treatment of uterine leiomyomas. The mean time to conception was 8 months after treatment. Live births occurred in 41% of pregnancies, with a 28% spontaneous abortion rate, an 11% rate of elective pregnancy termination, and 11 (20%) ongoing pregnancies beyond 20 gestational weeks. The mean birth weight was 3.3 kg, and the vaginal delivery rate was 64%. Preliminary pregnancy experience after MRgFUS is encouraging, with a high rate of delivered and ongoing pregnancies. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  17. Magnetic resonance-guided focused ultrasound surgery using an enhanced sonication technique in a pig muscle model

    Energy Technology Data Exchange (ETDEWEB)

    Kopelman, Doron [Department of Surgery B, ' HaEmek' Medical Center, Afula, and Technion, Israel Institute of Technology, Haifa (Israel)]. E-mail: Kopelman_d@clalit.org.il; Inbar, Yael [Department of Diagnostic Imaging and Focused Ultrasound Treatment Center, Sheba Medical Center, Tel-Hashomer (Israel); Hanannel, Arik [InSightec Ltd., Haifa (Israel); Freundlich, David [InSightec Ltd., Haifa (Israel); Vitek, Shuki [InSightec Ltd., Haifa (Israel); Schmidt, Rita [InSightec Ltd., Haifa (Israel); Sokolov, Amit [InSightec Ltd., Haifa (Israel); Hatoum, Ossama A. [Department of Surgery B, ' HaEmek' Medical Center, Afula, and the Technion, Israel Institute of Technology, Haifa (Israel); Rabinovici, Jaron [Department of Gynecology and Obstetrics, Sheba Medical Center, Tel-Aviv University, Tel-Hashomer (Israel)

    2006-08-15

    The purpose of this study: To evaluate the safety and efficacy of an enhanced magnetic resonance-guided focused ultrasound (MRgFUS) emission protocol that results in more extensive treatment by increasing the volume of each focal ablation using the same energy. Materials and methods: Six pigs were treated with an MRgFUS system combined with real-time MR, for imaging and temperature mapping, with 102 'enhanced' and 97 'regular' focal ablations performed on both buttock muscles. Real-time imaging, temperature mapping, and acoustic reflected spectrum data enabled immediate evaluation of the results. MR contrast-enhanced images and pathology examinations were used for confirmation. Results: The location of the ablated volume by 'enhanced' sonication is predictable, with a maximum possible shift of 6 mm toward, and 3 mm away, from the transducer. The ablated volume after enhanced sonication was, on average, 1.8 times larger than after a regular sonication of the same energy. Pathology results showed the same thermally induced damage patterns in the enhanced sonications and the regular sonications. Conclusion: Accelerated MRgFUS with enhanced sonication is a safe, controllable, and more effective tissue ablative modality than standard sonication. This new technology may significantly reduce the length of tumor ablation procedures. (Isn't the new technology you're talking about MRgFUS? If so, you don't need to repeat it at the end of this sentence.)

  18. Early health technology assessment of magnetic resonance-guided high intensity focused ultrasound ablation for the treatment of early-stage breast cancer

    NARCIS (Netherlands)

    Knuttel, Floortje M; Huijsse, Sèvrin E M; Feenstra, Talitha L; Moonen, Chrit T W; van den Bosch, Maurice A A J; Buskens, Erik; Greuter, Marcel J W; de Bock, Geertruida H

    2017-01-01

    BACKGROUND: Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) ablation is in development for minimally invasive treatment of breast cancer. Cost-effectiveness has not been assessed yet. An early health technology assessment was performed to estimate costs of MR-HIFU ablation,

  19. Early health technology assessment of magnetic resonance-guided high intensity focused ultrasound ablation for the treatment of early-stage breast cancer

    NARCIS (Netherlands)

    Knuttel, Floortje M.; Huijsse, Sèvrin E.M.; Feenstra, Talitha L.; Moonen, Chrit T.W.; van den Bosch, Maurice A.A.J.; Buskens, Erik; Greuter, Marcel J W; de Bock, Geertruida H.

    2017-01-01

    Background: Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) ablation is in development for minimally invasive treatment of breast cancer. Cost-effectiveness has not been assessed yet. An early health technology assessment was performed to estimate costs of MR-HIFU ablation,

  20. The effects of Magnetic Resonance Imaging-guided High-Intensity Focused Ultrasound ablation on human cadaver breast tissue.

    Science.gov (United States)

    Merckel, Laura G; Deckers, Roel; Baron, Paul; Bleys, Ronald L A W; van Diest, Paul J; Moonen, Chrit T W; Mali, Willem P Th M; van den Bosch, Maurice A A J; Bartels, Lambertus W

    2013-10-05

    Magnetic Resonance Imaging-guided High-Intensity Focused Ultrasound (MR-HIFU) is a promising technique for non-invasive breast tumor ablation. The purpose of this study was to investigate the effects of HIFU ablation and thermal exposure on ex vivo human breast tissue. HIFU ablations were performed in three unembalmed cadaveric breast specimens using a clinical MR-HIFU system. Sonications were performed in fibroglandular and adipose tissue. During HIFU ablation, time-resolved anatomical MR images were acquired to monitor macroscopic tissue changes. Furthermore, the breast tissue temperature was measured using a thermocouple to investigate heating and cooling under HIFU exposure. After HIFU ablation, breast tissue samples were excised and prepared for histopathological analysis. In addition, thermal exposure experiments were performed to distinguish between different levels of thermal damage using immunohistochemical staining. Irreversible macroscopic deformations up to 3.7 mm were observed upon HIFU ablation both in fibroglandular and in adipose tissue. No relationship was found between the sonication power or the maximum tissue temperature and the size of the deformations. Temperature measurements after HIFU ablation showed a slow decline in breast tissue temperature. Histopathological analysis of sonicated regions demonstrated ablated tissue and morphologically complete cell death. After thermal exposure, samples exposed to three different temperatures could readily be distinguished. In conclusion, the irreversible macroscopic tissue deformations in ex vivo human breast tissue observed during HIFU ablation suggest that it might be relevant to monitor tissue deformations during MR-HIFU treatments. Furthermore, the slow decrease in breast tissue temperature after HIFU ablation increases the risk of heat accumulation between successive sonications. Since cell death was inflicted after already 5 minutes at 75°C, MR-HIFU may find a place in non-invasive treatment of

  1. Histopathology of breast cancer after magnetic resonance-guided high-intensity focused ultrasound and radiofrequency ablation.

    Science.gov (United States)

    Knuttel, Floortje M; Waaijer, Laurien; Merckel, Laura G; van den Bosch, Maurice A A J; Witkamp, Arjen J; Deckers, Roel; van Diest, Paul J

    2016-08-01

    Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation and radiofrequency ablation (RFA) are being researched as possible substitutes for surgery in breast cancer patients. The histopathological appearance of ablated tissue has not been studied in great detail. This study aimed to compare histopathological features of breast cancer after MR-HIFU ablation and RFA. MR-HIFU ablation and RFA were performed in- and ex-vivo. Tumours in six mastectomy specimens were partially ablated with RFA or MR-HIFU. In-vivo MR-HIFU ablation was performed 3-6 days before excision; RFA was performed in the operation room. Tissue was fixed in formalin and processed to haematoxylin and eosin (H&E) and cytokeratin-8 (CK-8)-stained slides. Morphology and cell viability were assessed. Ex-vivo ablation resulted in clear morphological changes after RFA versus subtle differences after MR-HIFU. CK-8 staining was decreased or absent. H&E tended to underestimate the size of thermal damage. In-vivo MR-HIFU resulted in necrotic-like changes. Surprisingly, some ablated lesions were CK-8-positive. Histopathology after in-vivo RFA resembled ex-vivo RFA, with hyper-eosinophilic stroma and elongated nuclei. Lesion borders were sharp after MR-HIFU and indistinct after RFA. Histopathological differences between MR-HIFU-ablated tissue and RF-ablated tissue were demonstrated. CK-8 was more reliable for cell viability assessment than H&E when used directly after ablation, while H&E was more reliable in ablated tissue left in situ for a few days. Our results contribute to improved understanding of histopathological features in breast cancer lesions treated with minimally invasive ablative techniques. © 2016 John Wiley & Sons Ltd.

  2. Acoustic field characterization of a clinical magnetic resonance-guided high-intensity focused ultrasound system inside the magnet bore.

    Science.gov (United States)

    Kothapalli, Satya V V N; Altman, Michael B; Partanen, Ari; Wan, Leighton; Gach, H Michael; Straube, William; Hallahan, Dennis E; Chen, Hong

    2017-09-01

    With the expanding clinical application of magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU), acoustic field characterization of MR-HIFU systems is needed for facilitating regulatory approval and ensuring consistent and safe power output of HIFU transducers. However, the established acoustic field measurement techniques typically use equipment that cannot be used in a magnetic resonance imaging (MRI) suite, thus posing a challenge to the development and execution of HIFU acoustic field characterization techniques. In this study, we developed and characterized a technique for HIFU acoustic field calibration within the MRI magnet bore, and validated the technique with standard hydrophone measurements outside of the MRI suite. A clinical Philips MR-HIFU system (Sonalleve V2, Philips, Vantaa, Finland) was used to assess the proposed technique. A fiber-optic hydrophone with a long fiber was inserted through a 24-gauge angiocatheter and fixed inside a water tank that was placed on the HIFU patient table above the acoustic window. The long fiber allowed the hydrophone control unit to be placed outside of the magnet room. The location of the fiber tip was traced on MR images, and the HIFU focal point was positioned at the fiber tip using the MR-HIFU therapy planning software. To perform acoustic field mapping inside the magnet, the HIFU focus was positioned relative to the fiber tip using an MRI-compatible 5-axis robotic transducer positioning system embedded in the HIFU patient table. To perform validation measurements of the acoustic fields, the HIFU table was moved out of the MRI suite, and a standard laboratory hydrophone measurement setup was used to perform acoustic field measurements outside the magnetic field. The pressure field scans along and across the acoustic beam path obtained inside the MRI bore were in good agreement with those obtained outside of the MRI suite. At the HIFU focus with varying nominal acoustic powers of 10-500 W, the

  3. Magnetic resonance-guided focused ultrasound surgery (MRgFUS): Ablation of liver tissue in a porcine model

    Energy Technology Data Exchange (ETDEWEB)

    Kopelman, Doron [Department of Surgery B, ' HaEmek' Medical Center, Afula, and the Technion, Israel institute of technology, Haifa (Israel)]. E-mail: Kopelman_d@clalit.org.il; Inbar, Yael [Focused Ultrasound Treatment Center, Sheba Medical Center, Tel-Hashomer (Israel); Hanannel, Arik [InSightec Ltd., Tirat Hacarmel (Israel); Freundlich, David [InSightec Ltd., Tirat Hacarmel (Israel); Castel, David [Focused Ultrasound Treatment Center, Sheba Medical Center, Tel-Hashomer (Israel); Perel, Azriel [Department of Anesthesiology, and intensive care, Sheba Medical Center, Tel-Aviv University, Tel-Hashomer (Israel); Greenfeld, Adrian [Department of Anesthesiology, and intensive care, Sheba Medical Center, Tel-Aviv University, Tel-Hashomer (Israel); Salamon, Tal [Department of Surgery B, ' HaEmek' Medical Center, Afula, and the Technion, Israel institute of technology, Haifa (Israel); Sareli, Merab [Department of Surgery C, Sheba Medical Center, Tel-Aviv University, Tel-Hashomer (Israel); Valeanu, Adrian [Department of Surgery C, Sheba Medical Center, Tel-Aviv University, Tel-Hashomer (Israel); Papa, Moshe [Department of Surgery C, Sheba Medical Center, Tel-Aviv University, Tel-Hashomer (Israel)

    2006-08-15

    Background: Liver surgery is technically demanding and is considered a major procedure with relatively high morbidity rates. Magnetic resonance-guided focused ultrasound surgery (MRgFUS) uses focused ultrasonic energy to create a heat coagulation lesion, which can be achieved in a totally controlled, very accurate manner (<1 mm). The aim of this study was to evaluate the safety and accuracy of non-invasive focal ablation of liver tissue achieved by consecutive MRgFUS sonications. Materials and methods: Six MRgFUS procedures were performed in five pigs under general anesthesia, with the ExAblate 2000 system (InSightec, Israel). Real-time imaging and temperature mapping (Signa Twinspeed 1.5T, GEHC, USA) enabled the immediate evaluation of the results of each sonication. Different foci were chosen within the liver. These mock lesions were ablated by several sonications, each of them performed during 20-30 s of apnea. Between sonications, the pigs were normally ventilated. The pigs were sacrificed 3-21 days after the procedure and their livers were examined. Results: The MRgFUS created complete tissue destruction of mock lesions in different areas of the pig's liver. The lesion sizes in each animal varied according to the number of sonications used and the extent of overlap between adjacent sonications. The lesion ranged in size from 1.5 cm x 1.5 cm x 2.0 cm to 5.5 cm x 4.5 cm x 2.0 cm. There was no morbidity. Conclusions: MRgFUS under general anesthesia is a safe, completely non-invasive technology for the ablation of liver tissue. Liver tissue can be ablated in a very accurate manner, based on the pre-treatment planning on the MR images. The MR imaging characteristics, including real-time temperature mapping, enable real-time control of every step of the ablation process. Mechanical ventilation with intermittent periods of apnea is a technique that overcomes the problem of the respiratory movements of the liver.

  4. Magnetic resonance-guided focused ultrasound treatment of extra-abdominal desmoid tumors: a retrospective multicenter study.

    Science.gov (United States)

    Ghanouni, Pejman; Dobrotwir, Andrew; Bazzocchi, Alberto; Bucknor, Matthew; Bitton, Rachelle; Rosenberg, Jarrett; Telischak, Kristen; Busacca, Maurizio; Ferrari, Stefano; Albisinni, Ugo; Walters, Shannon; Gold, Garry; Ganjoo, Kristen; Napoli, Alessandro; Pauly, Kim Butts; Avedian, Raffi

    2017-02-01

    To assess the feasibility, safety and preliminary efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) for the treatment of extra-abdominal desmoid tumours. Fifteen patients with desmoid fibromatosis (six males, nine females; age range, 7-66 years) were treated with MRgFUS, with seven patients requiring multiple treatments (25 total treatments). Changes in viable and total tumour volumes were measured after treatment. Efficacy was evaluated using an exact one-sided Wilcoxon test to determine if the median reduction in viable tumour measured immediately after initial treatment exceeded a threshold of 50 % of the targeted volume. Median decrease after treatment of at least two points in numerical rating scale (NRS) worst and average pain scores was tested with an exact one-sided Wilcoxon test. Adverse events were recorded. After initial MRgFUS treatment, median viable targeted tumour volume decreased 63 %, significantly beyond our efficacy threshold (P = 0.0013). Median viable total tumour volume decreased (105 mL [interquartile range {IQR}, 217 mL] to 54 mL [IQR, 92 mL]) and pain improved (worst scores, 7.5 ± 1.9 vs 2.7 ± 2.6, P = 0.027; average scores, 6 ± 2.3 vs 1.3 ± 2, P = 0.021). Skin burn was the most common complication. MRgFUS significantly and durably reduced viable tumour volume and pain in this series of 15 patients with extra-abdominal desmoid fibromatosis. • Retrospective four-centre study shows MRgFUS safely and effectively treats extra-abdominal desmoid tumours • This non-invasive procedure can eradicate viable tumour in some cases • Alternatively, MRgFUS can provide durable control of tumour growth through repeated treatments • Compared to surgery or radiation, MRgFUS has relatively mild side effects.

  5. [Prospective study on magnetic resonance-guided focused ultrasound surgery for symptomatic uterine fibroid: short-term follow up].

    Science.gov (United States)

    Fan, Rong; Zhu, Lan; Gong, Xiao-ming; Xue, Hua-dan; Shi, Hai-feng; Jin, Zheng-yu; Chen, Guang-jun

    2013-03-01

    To evaluate the safety and efficacy of magnetic resonance-guided focused ultrasound surgery (MRgFUS) in treatment of symptomatic uterine leiomyoma among Chinese reproductive age women. From April 2010 to April 2012, 80 premenopausal women with symptomatic leiomyoma volunteered to participate in this prospective study in Department of Outpatient of Peking Union Medical College Hospital. Among 23 reproductive aged patients with size of uterus less than 16th gestational weeks, 2.5 to 10 cm of diameter of myoma, less than 10 myomas and expressing symptoms clearly were treated by MRgFUS. Treatment data, non-perfused volume ratio (NPVR) and adverse events were recorded. After treatment, patients were followed up at 1 week, 1, 3, 6, 12 and 24 months, respectively. Patients at initial screening and each time of the follow-up filled out uterine fibroid symptoms quality of life (UFS-QOL), which include symptoms severity score (SSS) and health-related quality of life (HRQL). The volumes of leiomyoma and uterine were evaluated on MRI before and after the treatment (at 6 and 12 months, respectively). Before operation, routine blood test were performed on all patients, anemia patients at 3 months and 1 year after treatment were checked with blood test. (1) Treatment data and adverse events: the mean therapeutic temperature was (69 ± 7)°C, the mean treatment time was (144 ± 62) min, the mean NPVR was (62 ± 23)%. Adverse events included mild erythema(1/23), abdominal cramp (8/23), vaginal discharge (5/23), and leg numbness (4/23). (2) The rate of secondary surgery: one patient was treated by myoectomy and hysterectomy within one year following up and 4 patients chose surgical treatment during the second-year follow-up. (3) Volume change:the volumes of leiomyoma before the treatment and 6, 12 months after the treatment are 75.6(P25 = 43.8, P75 = 128.9), 52.3(P25 = 23.8, P75 = 111.2), 45.9(P25 = 26.3, P75 = 71.7) cm(3), respectively; and the volumes of uterine before the

  6. Evaluation of superparamagnetic iron oxide-polymer composite microcapsules for magnetic resonance-guided high-intensity focused ultrasound cancer surgery.

    Science.gov (United States)

    Sun, Yang; Zheng, Yuanyi; Li, Pan; Wang, Dong; Niu, Chengcheng; Gong, Yuping; Huang, Rongzhong; Wang, Zhibiao; Wang, Zhigang; Ran, Haitao

    2014-11-03

    Superparamagnetic poly (lactic-co-glycolic acid) (PLGA)-coated Fe3O4 microcapsules are receiving increased attention as potential diagnostic and therapeutic modalities in the field of oncology. In this study, PLGA-coated Fe3O4 microcapsules were combined with a magnetic resonance imaging-guided high-intensity focused ultrasound (MR-guided HIFU) platform, with the objective of investigating the effects of these composite microcapsules regarding MR-guided HIFU liver cancer surgery in vivo. PLGA-coated Fe3O4 microcapsules consisting of a liquid core and a PLGA-Fe3O4 shell were fabricated using a modified double emulsion evaporation method. Their acute biosafety was confirmed in vitro using MDA cells and in vivo using rabbits. To perform MR-guided HIFU surgery, the microcapsules were intravenously injected into a rabbit liver tumor model before MR-guided HIFU. T2-weighted images and MR signal intensity in normal liver parenchyma and tumor tissue were acquired before and after injection, to assess the MR imaging ability of the microcapsules. After MR-guided HIFU ablation tissue temperature mapping, the coagulative volume and histopathology of the tumor tissue were analyzed to investigate the ablation effects of MR-guided HIFUs. Scanning and transmission electron microscopy showed that the microcapsules displayed a spherical morphology and a shell-core structure (mean diameter, 587 nm). The hysteresis curve displayed the typical superparamagnetic properties of the microcapsules, which are critical to their application in MR-guided HIFU surgery. In MR-guided HIFU surgery, these microcapsules functioned as an MRI contrast agent, induced significant hyperthermal enhancement (P microcapsules is a potentially synergistic technique regarding the enhancement of MR-guided HIFU cancer surgery.

  7. Dynamic contrast-enhanced magnetic resonance imaging predicts immediate therapeutic response of magnetic resonance-guided high-intensity focused ultrasound ablation of symptomatic uterine fibroids.

    Science.gov (United States)

    Kim, Young-Sun; Lim, Hyo K; Kim, Jae-Hun; Rhim, Hyunchul; Park, Byung Kwan; Keserci, Bilgin; Köhler, Max O; Bae, Duk-Soo; Kim, Byoung-Gie; Lee, Jeong-Won; Kim, Tae-Joong; Sokka, Shunmugavelu; Lee, Jung Hee

    2011-10-01

    : To evaluate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters in the prediction of the immediate therapeutic response of MR-guided high-intensity focused ultrasound (HIFU) therapy in the treatment of symptomatic uterine fibroids : Institutional review board approved this study, and informed consent was obtained from all participants. A total of 10 symptomatic uterine fibroids (diameter: mean, 8.9 cm; range, 4.7-12 cm) in 10 female patients (mean age, 42.2 years) were treated with MR-HIFU therapy using the volumetric ablation technique. DCE-MRI and conventional contrast-enhanced MRI were obtained as a baseline and as an immediate follow-up study, respectively. After regions of interest of each treatment cell were properly registered to both MRI studies, DCE-MRI parameters (K, ve, vp) and operator-controllable therapy parameters (power, treatment cell size, sonication depth) were investigated on a cell-by-cell basis to reflect tissue inhomogeneity. Two types of ablation efficacy indices (volume of 240 equivalent minutes at 43°C/treatment-cell volume, nonperfused volume/treatment-cell volume) were then correlated with those parameters using multiple linear regression analysis to determine which factors were significant predictors for ablation efficacy. : We used 293 treatment cells (4 mm, n = 12; 8 mm, n = 115; 12 mm, n = 149; 16 mm, n = 17), and all of them were analyzable. Ablation efficacies were 1.06 ± 0.58 and 0.67 ± 0.39. K (B = -12.035, P < 0.001 and B = -11.516, P < 0.001, respectively) among DCE-MRI parameters and acoustic power (B = 0.008, P < 0.001; B = 0.010, P < 0.001, respectively) among therapy parameters were revealed to be independently significant predictors for both types of ablation efficacy. : A higher K value at baseline DCE-MRI suggested a poor ablation efficacy of MR-HIFU therapy for symptomatic uterine fibroids.

  8. Magnetic resonance imaging-guided focused ultrasound treatment of symptomatic uterine fibroids: impact of technology advancement on ablation volumes in 115 patients.

    Science.gov (United States)

    Trumm, Christoph G; Stahl, Robert; Clevert, Dirk-André; Herzog, Peter; Mindjuk, Irene; Kornprobst, Sabine; Schwarz, Christina; Hoffmann, Ralf-Thorsten; Reiser, Maximilian F; Matzko, Matthias

    2013-06-01

    The aim of this study was to assess the impact of the advanced technology of the new ExAblate 2100 system (Insightec Ltd, Haifa, Israel) for magnetic resonance imaging (MRI)-guided focused ultrasound surgery on treatment outcomes in patients with symptomatic uterine fibroids, as measured by the nonperfused volume ratio. This is a retrospective analysis of 115 women (mean age, 42 years; range, 27-54 years) with symptomatic fibroids who consecutively underwent MRI-guided focused ultrasound treatment in a single center with the new generation ExAblate 2100 system from November 2010 to June 2011. Mean ± SD total volume and number of treated fibroids (per patient) were 89 ± 94 cm and 2.2 ± 1.7, respectively. Patient baseline characteristics were analyzed regarding their impact on the resulting nonperfused volume ratio. Magnetic resonance imaging-guided focused ultrasound treatment was technically successful in 115 of 123 patients (93.5%). In 8 patients, treatment was not possible because of bowel loops in the beam pathway that could not be mitigated (n = 6), patient movement (n = 1), and system malfunction (n = 1). Mean nonperfused volume ratio was 88% ± 15% (range, 38%-100%). Mean applied energy level was 5400 ± 1200 J, and mean number of sonications was 74 ± 27. No major complications occurred. Two cases of first-degree skin burn resolved within 1 week after the intervention. Of the baseline characteristics analyzed, only the planned treatment volume had a statistically significant impact on nonperfused volume ratio. With technological advancement, the outcome of MRI-guided focused ultrasound treatment in terms of the nonperfused volume ratio can be enhanced with a high safety profile, markedly exceeding results reported in previous clinical trials.

  9. Effect of applied energy in renal sympathetic denervation with magnetic resonance guided focused ultrasound in a porcine model.

    Science.gov (United States)

    Shea, Jill; de Bever, Joshua; Kholmovski, Eugene; Beal, Hannah; Hadley, J Rock; Minalga, Emilee; Salama, Mohamed E; Marrouche, Nassir F; Payne, Allison

    2017-01-01

    Past catheter-based and focused ultrasound renal denervation studies have indicated that procedure efficacy is related to the number of ablations performed or the amount of energy used for the ablation. This study extends those prior results and investigates energy level effects on the efficacy of MR guided focused ultrasound renal denervation performed in a porcine model. Twenty-four normotensive pigs underwent unilateral denervation at three intensity levels. The applied intensity level was retrospectively de-rated to account for variability in animal size. Efficacy was assessed through evaluating the norepinephrine present in the kidney medulla and through histological analysis. The treatment was performed under MRI guidance including pre- and post-procedure T1-weighted and quantitative T1 and T2 imaging. During treatment, the temperature in the near field of the ultrasound beam was monitored in real time with MR temperature imaging. Energy delivery in the regions surrounding the renal artery was independently confirmed through an invasive fiberoptic temperature probe placed in the right renal artery. Animals that underwent denervation at a de-rated acoustic intensity of greater than 1.2 kW/cm(2) had a significantly lower norepinephrine concentration in the kidney indicating successful denervation. Images obtained during the treatment indicated no tissue changes in the kidneys as a function of the procedure but there were significant T1 changes present in the right lumbar muscles, although only one animal had indication of muscle damage at the time of necropsy. While MR guided focused ultrasound renal denervation was found to be safe and effective in this normotensive animal model, the results indicated the need to incorporate patient-specific details in the treatment planning of MRgFUS renal denervation procedure.

  10. Successful Use of Magnetic Resonance-Guided Focused Ultrasound Surgery for Long-Term Pain Palliation in a Patient Suffering from Metastatic Bone Tumor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Eun; Yoon, Sang Wook; Kim, Kyoung Ah; Lee, Jong Tae [Dept. of Diagnostic Radiology, CHA Bundang Medical Center, CHA University College of Medicine, Seongnam (Korea, Republic of); Shay, Lilach [InSightec. Ltd, Hifa, (Israel); Lee, Kyong Sik [Dept. of General Surgery, CHA Bundang Medical Center, CHA University College of Medicine, Seongnam (Korea, Republic of)

    2011-08-15

    Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a clinically effective, non-invasive treatment for thermal ablation of various soft tissue tumors, and is effective in pain palliation following radiation therapy, as has been demonstrated in the initial studies of bone metastases. The current study evaluated the safety and clinical efficacy of MRgFUS for pain palliation prior to radiation therapy, in a patient with a solitary metastatic bone lesion. This is the first case report of MRgFUS treatment with a 1-year follow-up in a patient.

  11. Focus Group Guide

    Science.gov (United States)

    2017-07-01

    clarification.  Determine demographics and number needed for focus groups (all male, all female, mixed gender , by rank, by section, etc.; 8–15...members (based on section, rank, race, gender , etc.) view an issue? Are the concerns focused in a single section or do they seem to be unit-wide...Sexual Harassment (C) Sex Harassment Retaliation (D) Discrimination - Sex (E) Discrimination - Race (F) Discrimination - Disability (G

  12. Magnetic resonance guided high-intensity focused ultrasound mediated hyperthermia improves the intratumoral distribution of temperature-sensitive liposomal doxorubicin.

    Science.gov (United States)

    de Smet, Mariska; Hijnen, Nicole M; Langereis, Sander; Elevelt, Aaldert; Heijman, Edwin; Dubois, Ludwig; Lambin, Philippe; Grüll, Holger

    2013-06-01

    The aim of this study was to investigate the intratumoral distribution of a temperature-sensitive liposomal carrier and its encapsulated compounds, doxorubicin, and a magnetic resonance (MR) imaging contrast agent after high-intensity focused ultrasound (HIFU)-mediated hyperthermia-induced local drug release. (111)In-labeled temperature-sensitive liposomes encapsulating doxorubicin and [Gd(HPDO3A) (H(2)O)] were injected intravenously in the tail vein of rats (n = 12) bearing a subcutaneous rhabdomyosarcoma tumor on the hind leg. Immediately after the injection, local tumor hyperthermia (2 × 15 minutes) was applied using a clinical 3 T MR-HIFU system. Release of [Gd(HPDO3A)(H(2)O)] was studied in vivo by measuring the longitudinal relaxation rate R(1) with MR imaging. The presence of the liposomal carriers and the intratumoral distribution of doxorubicin were imaged ex vivo with autoradiography and fluorescence microscopy, respectively, for 2 different time points after injection (90 minutes and 48 hours). In hyperthermia-treated tumors, radiolabeled liposomes were distributed more homogeneously across the tumor than in the control tumors (coefficient of variation(hyp, 90 min) = 0.7 ± 0.2; coefficient of variation(cntrl, 90 min) = 1.1 ± 0.2). At 48 hours after injection, the liposomal accumulation in the tumor was enhanced in the hyperthermia group in comparison with the controls. A change in R(1) was observed in the HIFU-treated tumors, suggesting release of the contrast agent. Fluorescence images showed perivascular doxorubicin in control tumors, whereas in the HIFU-treated tumors, the delivered drug was spread over a much larger area and also taken up by tumor cells at a larger distance from blood vessels. Treatment with HIFU hyperthermia not only improved the immediate drug delivery, bioavailability, and intratumoral distribution but also enhanced liposomal accumulation over time. The sum of these effects may have a significant contribution to the therapeutic

  13. Magnetic resonance imaging-guided focused ultrasound surgery for symptomatic uterine fibroids: estimation of treatment efficacy using thermal dose calculations.

    Science.gov (United States)

    Yoon, Sang-Wook; Cha, Sun Hee; Ji, Young Geon; Kim, Hyun Cheol; Lee, Mee Hwa; Cho, Jin Ho

    2013-07-01

    To study the correlation between the predicted thermal dose volume (TDV) and the actual ablation volumes in MR-guided focused ultrasound surgery (MRgFUS) for symptomatic uterine fibroids, and to follow up the outcome for 12 months post-treatment. Phase-difference fast spoiled gradient-echo MR images were used to analyze thermal change during the energy deliveries of MRgFUS in 60 consecutive patients treated for symptomatic uterine fibroids. The TDV obtained through analysis of these MR images was compared with the non-perfused volume (NPV) measured on post-treatment contrast enhanced T1-weighted images. Final values of TDV ratio and NPV ratio were obtained by dividing these values by original fibroid volume. Patients were followed for 12 months post-treatment to assess symptomatic relief using the symptom severity score (SSS). Treatments in which we managed to reach a TDV ratio larger than 27% of the treated fibroid yielded a ratio of NPV to TDV of 1.1±0.5, indicating accurate control of the non-invasive procedure. Patient symptoms, as measured by the SSS, continuously decreased from a mean baseline score of 50±22 to 19±12 (P<0.0001) 12 months post-treatment. At large treatment volumes (exceeding 27% TDV ratio), thermal dose estimates correspond very closely to non-perfused volumes measured immediately post treatment. These large treatment volumes result in continuous clinical improvement throughout the first 12 months after MRgFUS. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. Non-invasive magnetic resonance-guided high intensity focused ultrasound ablation of a vascular malformation in the lower extremity : a case report

    NARCIS (Netherlands)

    van Breugel, Marjolein; Nijenhuis, Robbert J; Ries, Mario G; Toorop, RJ; Vonken, EPA; Wijlemans, JW; van den Bosch, Maurice A A J

    2015-01-01

    INTRODUCTION: Therapy of choice for symptomatic vascular malformations consists of surgery, sclerotherapy, or embolization. However, these techniques are invasive with possible complications and require hospitalization. We present a novel non-invasive technique, i.e., magnetic resonance-guided

  15. Magnetic resonance guided focused ultrasound surgery of uterine fibroids-The tissue effects of GnRH agonist pre-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Smart, O.C. [Department of Academic Obstetrics and Gynaecology, St. Mary' s Hospital and Imperial College School of Medicine, Praed Street, London W2 1NY (United Kingdom); Department of Magnetic Resonance Imaging, St. Mary' s Hospital and Imperial College School of Medicine, Praed Street, London W2 1NY (United Kingdom); Hindley, J.T. [Department of Academic Obstetrics and Gynaecology, St. Mary' s Hospital and Imperial College School of Medicine, Praed Street, London W2 1NY (United Kingdom); Regan, L. [Department of Academic Obstetrics and Gynaecology, St. Mary' s Hospital and Imperial College School of Medicine, Praed Street, London W2 1NY (United Kingdom); Gedroyc, W.M.W. [Department of Magnetic Resonance Imaging, St. Mary' s Hospital and Imperial College School of Medicine, Praed Street, London W2 1NY (United Kingdom)]. E-mail: w.gedroyc@imperial.ac.uk

    2006-08-15

    Objective: The purpose of this study was to determine the ablative effect of magnetic resonance guided focused ultrasound (MRgFUS) on fibroid tissue following the administration of gonadotrophin releasing hormone (GnRH) agonist. Study design: Fifty women with clinically symptomatic uterine fibroids were treated. Those with uterine diameter of 10 cm or greater were given 3 months pre-treatment with GnRH agonists. Data regarding number of ultrasound sonications, Joules of energy delivered and volume of thermal destruction was recorded. Results: Twenty-seven subjects were given GnRH agonist therapy before MRgFUS and 23 women underwent MRgFUS without pre-treatment. All patients in both study groups completed MR guided FUS as an outpatient procedure with no device related adverse events reported. In the group of women who received GnRH agonists, the volume of ablation was significantly larger than that in the control group (0.06 cm{sup 3} versus 0.03 cm{sup 3}, P < 0.05), per Joule of energy applied. Conclusion: The use of GnRH agonists potentiates the thermal effects of MRgFUS in women undergoing treatment of uterine fibroids.

  16. Feasibility of magnetic resonance imaging-guided high intensity focused ultrasound therapy for ablating uterine fibroids in patients with bowel lies anterior to uterus

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lian; Chen Wenzhi [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); Liu Yinjiang; Hu Xiao [National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Zhou Kun [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); Chen Li [National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Peng Song; Zhu Hui [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); Zou Huiling [National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Bai Jin [Institute of Ultrasound Engineering in Medicine of Chongqing University of Medical Sciences, Chongqing 400016 (China); Wang Zhibiao [Clinical Center for Tumour Therapy of 2nd Affiliated Hospital of Chongqing University of Medical Sciences, Chongqing 400010 (China); National Engineering Research Center of Ultrasound Medicine, Chongqing 400010 (China); Institute of Ultrasound Engineering in Medicine of Chongqing University of Medical Sciences, Chongqing 400016 (China)], E-mail: wangzhibiao@haifu.com.cn

    2010-02-15

    Purpose: To prospectively evaluate the feasibility of magnetic resonance (MR) imaging-guided high intensity focused ultrasound (HIFU) therapeutic ablation of uterine fibroids in patients with bowel lies anterior to uterus. Materials and methods: Twenty-one patients with 23 uterine fibroids underwent MR imaging-guided high intensity focused ultrasound treatment, with a mean age of 39.4 {+-} 6.9 (20-49) years, with fibroids average measuring 6.0 {+-} 1.6 (range, 2.9-9.5) cm in diameter. After being compressed with a degassed water balloon on abdominal wall, MR imaging-guided high intensity focused ultrasound treatment was performed under conscious sedation by using fentanyl and midazolam. This procedure was performed by a Haifu JM focused ultrasound tumour therapeutic system (JM2.5C, Chongqing Haifu Technology Co., Ltd., China), in combination with a 1.5-Tesla MRI system (Symphony, Siemens, Germany), which provides real-time guidance and control. Contrast-enhanced MR imaging was performed to evaluate the efficacy of thermal ablation immediately and 3 months after HIFU treatment. The treatment time and adverse events were recorded. Results: The mean fibroid volume was 97.0 {+-} 78.3 (range, 12.7-318.3) cm{sup 3}. According to the treatment plan, an average 75.0 {+-} 11.4% (range, 37.8-92.4%) of the fibroid volume was treated. The mean fibroid volume immediately after HIFU was 109.7 {+-} 93.1 (range, 11.9-389.6) cm{sup 3}, slightly enlarged because of edema. The average non-perfused volume was 83.3 {+-} 71.7 (range, 7.7-282.9) cm{sup 3}, the average fractional ablation, which was defined as non-perfused volume divided by the fibroid volume immediately after HIFU treatment, was 76.9 {+-} 18.7% (range, 21.0-97.0%). There were no statistically significant differences between the treatment volume and the non-perfused volume. Follow-up magnetic resonance imaging (MRI) at 3 months obtained in 12 patients, the fibroid volume decreased by 31.4 {+-} 29.3% (range, -1.9 to 60

  17. Expulsion of Fibroids to the Endometrial Cavity after Magnetic Resonance Imaging-guided High Intensity Focused Ultrasound Surgery (MRgFUS) Treatment of Intramural Uterine Fibroids.

    Science.gov (United States)

    Jeong, Jae-Hyeok; Hong, Gil Pyo; Kim, Yu-Ri; Hong, Da Gyo; Ha, Jae-Eun; Yeom, Jung In; Kim, Eun-Jeong; Kim, Hyung-Il; Lee, Kyu-Sup

    2016-12-01

    This report seeks to introduce some cases of the patients who received magnetic resonance imaging (MRI)-guided high intensity focused ultrasound (HIFU) surgery (MRgFUS)-based intramural uterine fibroids treatment where the post-MRgFUS intramural uterine fibroids decreased in its volume and protruded towards the endometrial cavity to be expelled by hysteroscopy. Of the 157 patients who had received MRgFUS treatment in the Obstetrics and Gynecology of the Hospital from March, 2015 to February, 2016; this study examined 6 of the cases where, after high intensity focused ultrasound treatment, intramural uterine fibroids protruded towards the endometrial cavity to be removed by hysteroscopic myomectomy. The high intensity focused ultrasound utilized in the cases were Philips Achieva 1.5 Tesla MR (Philips Healthcare, Best, The Netherlands) and Sonalleve HIFU system. The volume of fibroids ranged from 26.0 cm3 to 199.5 cm3, averaging 95.6 cm3. The major axis length ranged from 4.0 cm to 8.2 cm, averaging 6.3 cm. Fibroid location in all of the patients was in intramural uterine before treatment but after the high intensity focused ultrasound treatment, the fibroids were observed to protrude towards the endometrial cavity in at least Day 5 or up to Day 73 to allow hysteroscopic myomectomy. In some cases, after an intramural uterine fibroid is treated with MRgFUS, fibroid volume is decreased and the fibroid protrudes towards the endometrial cavity. In this case, hysteroscopic myomectomy can be a useful solution.

  18. Boiling histotripsy lesion characterization on a clinical magnetic resonance imaging-guided high intensity focused ultrasound system.

    Science.gov (United States)

    Eranki, Avinash; Farr, Navid; Partanen, Ari; V Sharma, Karun; Chen, Hong; Rossi, Christopher T; Kothapalli, Satya V V N; Oetgen, Matthew; Kim, AeRang; H Negussie, Ayele; Woods, David; J Wood, Bradford; C W Kim, Peter; S Yarmolenko, Pavel

    2017-01-01

    High intensity focused ultrasound (HIFU) is a non-invasive therapeutic technique that can thermally ablate tumors. Boiling histotripsy (BH) is a HIFU approach that can emulsify tissue in a few milliseconds. Lesion volume and temperature effects for different BH sonication parameters are currently not well characterized. In this work, lesion volume, temperature distribution, and area of lethal thermal dose were characterized for varying BH sonication parameters in tissue-mimicking phantoms (TMP) and demonstrated in ex vivo tissues. The following BH sonication parameters were varied using a clinical MR-HIFU system (Sonalleve V2, Philips, Vantaa, Finland): acoustic power, number of cycles/pulse, total sonication time, and pulse repetition frequency (PRF). A 3×3×3 pattern was sonicated inside TMP's and ex vivo tissues. Post sonication, lesion volumes were quantified using 3D ultrasonography and temperature and thermal dose distributions were analyzed offline. Ex vivo tissues were sectioned and stained with H&E post sonication to assess tissue damage. Significant increase in lesion volume was observed while increasing the number of cycles/pulse and PRF. Other sonication parameters had no significant effect on lesion volume. Temperature full width at half maximum at the end of sonication increased significantly with all parameters except total sonication time. Positive correlation was also found between lethal thermal dose and lesion volume for all parameters except number of cycles/pulse. Gross pathology of ex vivo tissues post sonication displayed either completely or partially damaged tissue at the focal region. Surrounding tissues presented sharp boundaries, with little or no structural damage to adjacent critical structures such as bile duct and nerves. Our characterization of effects of HIFU sonication parameters on the resulting lesion demonstrates the ability to control lesion morphologic and thermal characteristics with a clinical MR-HIFU system in TMP's and

  19. Boiling histotripsy lesion characterization on a clinical magnetic resonance imaging-guided high intensity focused ultrasound system.

    Directory of Open Access Journals (Sweden)

    Avinash Eranki

    Full Text Available High intensity focused ultrasound (HIFU is a non-invasive therapeutic technique that can thermally ablate tumors. Boiling histotripsy (BH is a HIFU approach that can emulsify tissue in a few milliseconds. Lesion volume and temperature effects for different BH sonication parameters are currently not well characterized. In this work, lesion volume, temperature distribution, and area of lethal thermal dose were characterized for varying BH sonication parameters in tissue-mimicking phantoms (TMP and demonstrated in ex vivo tissues.The following BH sonication parameters were varied using a clinical MR-HIFU system (Sonalleve V2, Philips, Vantaa, Finland: acoustic power, number of cycles/pulse, total sonication time, and pulse repetition frequency (PRF. A 3×3×3 pattern was sonicated inside TMP's and ex vivo tissues. Post sonication, lesion volumes were quantified using 3D ultrasonography and temperature and thermal dose distributions were analyzed offline. Ex vivo tissues were sectioned and stained with H&E post sonication to assess tissue damage.Significant increase in lesion volume was observed while increasing the number of cycles/pulse and PRF. Other sonication parameters had no significant effect on lesion volume. Temperature full width at half maximum at the end of sonication increased significantly with all parameters except total sonication time. Positive correlation was also found between lethal thermal dose and lesion volume for all parameters except number of cycles/pulse. Gross pathology of ex vivo tissues post sonication displayed either completely or partially damaged tissue at the focal region. Surrounding tissues presented sharp boundaries, with little or no structural damage to adjacent critical structures such as bile duct and nerves.Our characterization of effects of HIFU sonication parameters on the resulting lesion demonstrates the ability to control lesion morphologic and thermal characteristics with a clinical MR-HIFU system in

  20. Template-Free Synthesis of Hollow/Porous Organosilica-Fe3O4 Hybrid Nanocapsules toward Magnetic Resonance Imaging-Guided High-Intensity Focused Ultrasound Therapy.

    Science.gov (United States)

    Ma, Ming; Yan, Fei; Yao, Minghua; Wei, Zijun; Zhou, Dongliang; Yao, Heliang; Zheng, Hairong; Chen, Hangrong; Shi, Jianlin

    2016-11-09

    Entirely differing from the common templating-based multistep strategy for fabricating multifunctional hollow mesoporous silica nanoparticles (HMSN), a facile and template-free synthetic strategy has been established to construct a unique hollow/mesoporous organosilica nanocapsule (OSNC) concurrently encapsulating both isopentyl acetate (PeA) liquid and superparamagnetic iron oxides inside (denoted as PeA@OSNC). This novel material exhibits ultrasmall and uniform particle size (∼82 nm), high surface area (∼534 m2·g-1), and excellent colloidal stability in aqueous solution. The oil-phase PeA with relatively low boiling point (142 °C) and high volatility not only plays a crucial role in formation of a large hollow cavity from the viewpoint of structural design but also enables the PeA@OSNC to act as an efficient enhancement agent in high-intensity focused ultrasound (HIFU) therapy. Moreover, the unique satellite-like distribution of Fe3O4 nanoparticles (NP) on the organosilica shell offered excellent magnetic resonance imaging (MRI) contrast capability of PeA@OSNC in vitro and in vivo. More importantly, such a novel theranostic agent has favorable biosafety, which is very promising for future clinical application in MRI-guided HIFU therapy.

  1. Preservation of the endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound ablation of submucosal uterine fibroids.

    Science.gov (United States)

    Kim, Young-Sun; Kim, Tae-Joong; Lim, Hyo Keun; Rhim, Hyunchul; Jung, Sin-Ho; Ahn, Joong Hyun; Lee, Jeong-Won; Kim, Byoung-Gie

    2017-09-01

    To evaluate the integrity of endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) ablation of submucosal uterine fibroids based on contrast-enhanced MRI findings, and to identify the risk factors for endometrial impairment. In total, 117 submucosal fibroids (diameter: 5.9 ± 3.0 cm) in 101 women (age: 43.6 ± 4.4 years) treated with MR-HIFU ablation were retrospectively analysed. Endometrial integrity was assessed with contrast-enhanced T1-weighted images at immediate (n = 101), 3-month (n = 62) and 12-month (n = 15) follow-ups. Endometrial impairment was classified into grades 0 (continuous endometrium), 1 (pin-point, full-thickness discontinuity), 2 (between grade 1 and 3), or 3 (full-thickness discontinuity >1 cm). Risk factors were assessed with generalized estimating equation (GEE) analysis. Among 117 fibroids, grades 0, 1, 2 and 3 endometrial impairments were observed at initial examination in 56.4%, 24.8%, 13.7% and 4.3%, respectively. Among 37 fibroid cases of endometrial impairment for which follow-ups were conducted, 30 showed improvements at 3- and/or 12-month follow-up. GEE analysis revealed the degree of endometrial protrusion was significantly associated with severity of endometrial injury (P HIFU ablation of submucosal fibroids, endometrial enhancement was preserved intact or minimally impaired in most cases. Impaired endometrium, which is more common after treating endometrially-protruded fibroids, may recover spontaneously. • After MR-HIFU ablation for submucosal fibroid, endometrium is mostly preserved/minimally impaired. • Endometrial-protruded submucosal fibroid is susceptible to more severe endometrial impairment. • The impaired endometrium may recover spontaneously at follow-up MR exams.

  2. Magnetic Resonance Imaging-Guided High-Intensity Focused Ultrasound Ablation of Uterine Fibroids: Effect of Bowel Interposition on Procedure Feasibility and a Unique Bowel Displacement Technique.

    Directory of Open Access Journals (Sweden)

    Young-Sun Kim

    Full Text Available To evaluate the effect of bowel interposition on assessing procedure feasibility, and the usefulness and limiting conditions of bowel displacement techniques in magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU ablation of uterine fibroids.Institutional review board approved this study. A total of 375 screening MR exams and 206 MR-HIFU ablations for symptomatic uterine fibroids performed between August 2010 and March 2015 were retrospectively analyzed. The effect of bowel interposition on procedure feasibility was assessed by comparing pass rates in periods before and after adopting a unique bowel displacement technique (bladder filling, rectal filling and subsequent bladder emptying; BRB maneuver. Risk factors for BRB failure were evaluated using logistic regression analysis.Overall pass rates of pre- and post-BRB periods were 59.0% (98/166 and 71.7% (150/209, and in bowel-interposed cases they were 14.6% (7/48 and 76.4% (55/72, respectively. BRB maneuver was technically successful in 81.7% (49/60. Through-the-bladder sonication was effective in eight of eleven BRB failure cases, thus MR-HIFU could be initiated in 95.0% (57/60. A small uterus on treatment day was the only significant risk factor for BRB failure (B = 0.111, P = 0.017.The BRB maneuver greatly reduces the fraction of patients deemed ineligible for MR-HIFU ablation of uterine fibroids due to interposed bowels, although care is needed when the uterus is small.

  3. Preservation of the endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound ablation of submucosal uterine fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young-sun [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Uterine Fibroid Integrated Management Center, MINT Intervention Hospital, Department of Radiology, Seoul (Korea, Republic of); Kim, Tae-Joong; Lee, Jeong-Won; Kim, Byoung-Gie [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Obstetrics and Gynecology, Seoul (Korea, Republic of); Lim, Hyo Keun [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); SAIHST, Sungkyunkwan University, Department of Health Sciences and Technology, Seoul (Korea, Republic of); Rhim, Hyunchul [Samsung Medical Center, Sungkyunkwan University School of Medicine, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Jung, Sin-Ho [SAIHST, Sungkyunkwan University, Department of Health Sciences and Technology, Seoul (Korea, Republic of); Samsung Medical Center, Department of Biostatistics and Clinical Epidemiology, Seoul (Korea, Republic of); Ahn, Joong Hyun [Samsung Biomedical Research Institute, Samsung Medical Center, Biostatistics Team, Seoul (Korea, Republic of)

    2017-09-15

    To evaluate the integrity of endometrial enhancement after magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) ablation of submucosal uterine fibroids based on contrast-enhanced MRI findings, and to identify the risk factors for endometrial impairment. In total, 117 submucosal fibroids (diameter: 5.9 ± 3.0 cm) in 101 women (age: 43.6 ± 4.4 years) treated with MR-HIFU ablation were retrospectively analysed. Endometrial integrity was assessed with contrast-enhanced T1-weighted images at immediate (n = 101), 3-month (n = 62) and 12-month (n = 15) follow-ups. Endometrial impairment was classified into grades 0 (continuous endometrium), 1 (pin-point, full-thickness discontinuity), 2 (between grade 1 and 3), or 3 (full-thickness discontinuity >1 cm). Risk factors were assessed with generalized estimating equation (GEE) analysis. Among 117 fibroids, grades 0, 1, 2 and 3 endometrial impairments were observed at initial examination in 56.4%, 24.8%, 13.7% and 4.3%, respectively. Among 37 fibroid cases of endometrial impairment for which follow-ups were conducted, 30 showed improvements at 3- and/or 12-month follow-up. GEE analysis revealed the degree of endometrial protrusion was significantly associated with severity of endometrial injury (P < 0.0001). After MR-HIFU ablation of submucosal fibroids, endometrial enhancement was preserved intact or minimally impaired in most cases. Impaired endometrium, which is more common after treating endometrially-protruded fibroids, may recover spontaneously. (orig.)

  4. Temperature- and frequency-dependent dielectric properties of biological tissues within the temperature and frequency ranges typically used for magnetic resonance imaging-guided focused ultrasound surgery.

    Science.gov (United States)

    Fu, Fanrui; Xin, Sherman Xuegang; Chen, Wufan

    2014-02-01

    This study aimed to obtain the temperature- and frequency-dependent dielectric properties of tissues subjected to magnetic resonance (MR) scanning for MR imaging-guided focused ultrasound surgery (MRgFUS). These variables are necessary to calculate radio frequency electromagnetic fields distribution and specific radio frequency energy absorption rate (SAR) in the healthy tissues surrounding the target tumours, and their variation may affect the efficacy of advanced RF pulses. The dielectric properties of porcine uterus, liver, kidney, urinary bladder, skeletal muscle, and fat were determined using an open-ended coaxial probe method. The temperature range was set from 36 °C to 60 °C; and the frequencies were set at 42.58 (1 T), 64 (1.5 T), 128 (3 T), 170 (4 T), 298 (7 T), 400 (9 T), and 468 MHz (11 T). Within the temperature and frequency ranges, the dielectric constants were listed as follows: uterus 49.6-121.64, liver 44.81-127.68, kidney 37.3-169.26, bladder 42.43-125.95, muscle 58.62-171.7, and fat 9.2327-20.2295. The following conductivities were obtained at the same temperature and frequency ranges: uterus 0.5506-1.4419, liver 0.5174-0.9709, kidney 0.8061-1.3625, bladder 0.6766-1.1817, muscle 0.8983-1.3083, and fat 0.1552-0.2316. The obtained data are consistent with the temperature and frequency ranges typically used in MRgFUS and thus can be used as reference to calculate radio frequency electromagnetic fields and SAR distribution inside the healthy tissues subjected to MR scanning for MRgFUS.

  5. Magnetic resonance image guided brachytherapy.

    Science.gov (United States)

    Tanderup, Kari; Viswanathan, Akila N; Kirisits, Christian; Frank, Steven J

    2014-07-01

    The application of magnetic resonance image (MRI)-guided brachytherapy has demonstrated significant growth during the past 2 decades. Clinical improvements in cervix cancer outcomes have been linked to the application of repeated MRI for identification of residual tumor volumes during radiotherapy. This has changed clinical practice in the direction of individualized dose administration, and resulted in mounting evidence of improved clinical outcome regarding local control, overall survival as well as morbidity. MRI-guided prostate high-dose-rate and low-dose-rate brachytherapies have improved the accuracy of target and organs-at-risk delineation, and the potential exists for improved dose prescription and reporting for the prostate gland and organs at risk. Furthermore, MRI-guided prostate brachytherapy has significant potential to identify prostate subvolumes and dominant lesions to allow for dose administration reflecting the differential risk of recurrence. MRI-guided brachytherapy involves advanced imaging, target concepts, and dose planning. The key issue for safe dissemination and implementation of high-quality MRI-guided brachytherapy is establishment of qualified multidisciplinary teams and strategies for training and education. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Intra-articular benign bone lesions treated with Magnetic Resonance-guided Focused Ultrasound (MRgFUS): imaging follow-up and clinical results.

    Science.gov (United States)

    Arrigoni, Francesco; Barile, Antonio; Zugaro, Luigi; Splendiani, Alessandra; Di Cesare, Ernesto; Caranci, Ferdinando; Ierardi, Anna Maria; Floridi, Chiara; Angileri, Alessio Salvatore; Reginelli, Alfonso; Brunese, Luca; Masciocchi, Carlo

    2017-04-01

    Purpose of this study was to evaluate the employment of MRI-guided Focused Ultrasound (MRgFUS) for treatment of intra-articular benign bone lesions as alternative to surgery, and to monitor the success of the treatment on CT and MRI images. From March 2011 to August 2013, 14 intra-articular benign bone lesions were treated with MRgFUS. All patients were studied by CT and MR imaging. Pain was measured using the visual analogue scale (VAS) before and after treatment (6 and 12 months). All patients in our series demonstrated regression in painful symptomatology during screening. A significant drop in the mean VAS pain score (from 7.8 to 0.6) was observed at 12-month follow-up, and pain medication was no longer needed after treatment. No complications were observed. Three diagnostic imaging signs were found suggesting absence of biological activity and confirming the clinical findings: calcification of the treated lesion, lack of contrast enhancement and disappearance of bone oedema around the lesions. the employment of MRgFUS is safe and effective in the treatment of intra-articular benign bone lesions. The clinical outcome is satisfactory, and the success of the treatment is confirmed by diagnostic imaging.

  7. Uterine fibroids: Influence of "T2-Rim sign" on immediate therapeutic responses to magnetic resonance imaging-guided high-intensity focused ultrasound ablation.

    Science.gov (United States)

    Yeo, Sin Yuin; Kim, Young-Sun; Lim, Hyo Keun; Rhim, Hyunchul; Jung, Sin-Ho; Hwang, Na Young

    2017-12-01

    To investigate the influence of a high-signal-intensity peripheral rim on T2-weighted MR images (i.e., T2-rim sign) on the immediate therapeutic responses of MR-guided high intensity focused ultrasound (MR-HIFU) ablation of uterine fibroids. This retrospective study was approved by the institutional review board, and patient informed consent was obtained for MR-HIFU ablation. In total, 196 fibroids (diameter 6.2±2.6cm) in 123 women (age 43.4±5.0 years) who underwent MR-HIFU ablation from January 2013 to April 2016 were included. The effects of a T2-rim sign on the immediate therapeutic responses (non-perfused volume [NPV] ratio, ablation efficiency [NPV/treatment cell volume], ablation quality [grade 1-5, poor to excellent]) were investigated with univariable and multivariable analyses using generalized estimating equation (GEE) analysis. In multivariable analysis, T2 signal intensity ratio of fibroids-to-skeletal muscle, relative peak enhancement of fibroids, and subcutaneous fat thickness were also considered. The presence of a T2-rim sign significantly lowered the NPV ratio (54.0±28.0% vs. 83.7±17.7%), ablation efficiency (0.6±0.5 vs. 1.3±0.6), ablation quality (3.1±1.2 vs. 4.2±0.8), (P<0.0001). GEE analysis showed that the presence of a T2-rim sign was independently significant for ablation efficiency and ablation quality (P<0.05). Uterine fibroids with a T2-rim sign showed significantly poorer immediate therapeutic responses to MR-HIFU ablation. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Breast magnetic resonance imaging guided biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Bo La; Kim, Sun Mi; Jang, Mi Jung [Dept. of Radiology, Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Cho, Nariya; Moon, Woo Kyung [Dept. of Radiology, Seoul National University Hospital, Seoul (Korea, Republic of); Kim, Hak Hee [Dept. of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    Despite the high sensitivity of breast magnetic resonance imaging (MRI), pathologic confirmation by biopsy is essential because of limited specificity. MRI-guided biopsy is required in patients with lesions only seen on MRI. We review preprocedural considerations and the technique of MRI-guided biopsy, challenging situations and trouble-shooting, and correlation of radiologic and pathologic findings.

  9. Focused ultrasound guided relocation of kidney stones

    OpenAIRE

    Nitin Abrol; Kekre, Nitin S.

    2015-01-01

    Purpose: Complete removal of all fragments is the goal of any intervention for urinary stones. This is more important in lower pole stones where gravity and spatial orientation of lower pole infundibulum may hinder spontaneous passage of fragments. Various adjuvant therapies (inversion, diuresis, percussion, oral citrate, etc.) are described to enhance stone-free rate but are not widely accepted. Focused ultrasound-guided relocation of fragments is a recently described technique aimed at impr...

  10. Focused ultrasound guided relocation of kidney stones.

    Science.gov (United States)

    Abrol, Nitin; Kekre, Nitin S

    2015-01-01

    Complete removal of all fragments is the goal of any intervention for urinary stones. This is more important in lower pole stones where gravity and spatial orientation of lower pole infundibulum may hinder spontaneous passage of fragments. Various adjuvant therapies (inversion, diuresis, percussion, oral citrate, etc.) are described to enhance stone-free rate but are not widely accepted. Focused ultrasound-guided relocation of fragments is a recently described technique aimed at improving results of intervention for stone disease. Purpose of this review is to discuss development of this technology and its potential clinical applications. Pubmed search was made using key words "Focused ultrasound" and "kidney stone". All English language articles were reviewed by title. Relevant studies describing development and application of focused ultrasound in renal stones were selected for review. Focused ultrasound has proven its efficacy in successfully relocating up to 8 mm stone fragments in vitro and in pigs. Relocation is independent of stone composition. The latest model allows imaging and therapy with a single handheld probe facilitating its use by single operator. The acoustic energy delivered by the new prototype is even less than that used for extracorporeal shock wave lithotripsy. Therapeutic exposure has not caused thermal injury in pig kidneys. Focused ultrasound-guided relocation of stones is feasible. Though it is safe in application in pigs, technology is awaiting approval for clinical testing in human beings. This technology has many potential clinical applications in the management of stone disease.

  11. Focused ultrasound guided relocation of kidney stones

    Directory of Open Access Journals (Sweden)

    Nitin Abrol

    2015-01-01

    Full Text Available Purpose: Complete removal of all fragments is the goal of any intervention for urinary stones. This is more important in lower pole stones where gravity and spatial orientation of lower pole infundibulum may hinder spontaneous passage of fragments. Various adjuvant therapies (inversion, diuresis, percussion, oral citrate, etc. are described to enhance stone-free rate but are not widely accepted. Focused ultrasound-guided relocation of fragments is a recently described technique aimed at improving results of intervention for stone disease. Purpose of this review is to discuss development of this technology and its potential clinical applications. Materials and Methods: Pubmed search was made using key words "Focused ultrasound" and "kidney stone." All English language articles were reviewed by title. Relevant studies describing development and application of focused ultrasound in renal stones were selected for review. Results: Focused ultrasound has proven its efficacy in successfully relocating up to 8 mm stone fragments in vitro and in pigs. Relocation is independent of stone composition. The latest model allows imaging and therapy with a single handheld probe facilitating its use by single operator. The acoustic energy delivered by the new prototype is even less than that used for extracorporeal shock wave lithotripsy. Therapeutic exposure has not caused thermal injury in pig kidneys. Conclusion: Focused ultrasound-guided relocation of stones is feasible. Though it is safe in application in pigs, technology is awaiting approval for clinical testing in human beings. This technology has many potential clinical applications in the management of stone disease.

  12. Uterine Leiomyomas: MR Imaging–guided Focused Ultrasound Surgery—Imaging Predictors of Success

    OpenAIRE

    Lénárd, Zsuzsanna M.; McDannold, Nathan J.; Fennessy, Fiona M.; Stewart, Elizabeth A.; Jolesz, Ferenc A.; Hynynen, Kullervo; Tempany, Clare M. C.

    2008-01-01

    Purpose: To retrospectively assess the magnetic resonance (MR) imaging predictors of success at reducing uterine leiomyoma volume and achieving patient symptom relief 12 months after MR imaging–guided focused ultrasound surgery.

  13. Diffusion-weighted magnetic resonance imaging using different b-value combinations for the evaluation of treatment results after volumetric MR-guided high-intensity focused ultrasound ablation of uterine fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Ikink, Marlijne E.; Voogt, Marianne J.; Bosch, Maurice A.A.J. van den; Nijenhuis, Robbert J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Keserci, Bilgin [Samsung Medical Center, High-intensity Focused Ultrasound (HIFU) Center, Seoul (Korea, Republic of); Philips Healthcare, Advanced Science and Development, Seoul (Korea, Republic of); Kim, Young-sun [Samsung Medical Center, High-intensity Focused Ultrasound (HIFU) Center, Seoul (Korea, Republic of); Samsung Medical Center, Sunkyunkwan University, Department of Radiology and Center for Imaging Science, Seoul (Korea, Republic of); Vincken, Koen L.; Bartels, Lambertus W. [University Medical Center Utrecht, Department of Radiology and Image Sciences Institute, Utrecht (Netherlands)

    2014-09-15

    To assess the value of diffusion-weighted magnetic resonance imaging (DWI) and apparent diffusion coefficient (ADC) mapping using different b-value combinations for treatment evaluation after magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) of uterine fibroids. Fifty-six patients with 67 uterine fibroids were treated with volumetric MR-HIFU. Pre-treatment and post-treatment images were obtained using contrast-enhanced T1-weighted MRI (CE-T1WI) and DWI using b = 0, 200, 400, 600, 800 s/mm{sup 2}. ADC maps were generated using subsets of b-values to investigate the effects of tissue ablation on water diffusion and perfusion in fibroids treated with MR-HIFU. Four combinations of b-values were used: (1) all b-values; (2) b = 0, 200 s/mm{sup 2}; (3) b = 400, 600, 800 s/mm{sup 2}; and (4) b = 0, 800 s/mm{sup 2}. Using the lowest b-values (0 and 200 s/mm{sup 2}), the mean ADC value in the ablated tissue reduced significantly (p < 0.001) compared with baseline. Calculating the ADC value with the highest b-values (400, 600, 800 s/mm{sup 2}), the ADC increased significantly (p < 0.001) post-treatment. ADC maps calculated with the lowest b-values resulted in the best visual agreement of non-perfused fibroid tissue detected on CE images. Other b-value combinations and normal myometrium showed no difference in ADC after MR-HIFU treatment. A decrease in contrast agent uptake within the ablated region on CE-T1WI was correlated to a significantly decreased ADC when b = 0 and 200 s/mm{sup 2} were used. (orig.)

  14. Scaled signal intensity of uterine fibroids based on T2-weighted MR images: a potential objective method to determine the suitability for magnetic resonance-guided focused ultrasound surgery of uterine fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyun [CHA University, Comprehensive Gynecologic Cancer Center, CHA Bundang Medical Center, Gyunggi-do (Korea, Republic of); Yoon, Sang-Wook [CHA University, Department of Diagnostic Radiology, CHA Bundang Medical Center, Sungnam-si, Gyunggi-do (Korea, Republic of); Sokolov, Amit [InSightec Ltd., Haifa (Israel)

    2015-12-15

    Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive method to treat uterine fibroids. To help determine the patient suitability for MRgFUS, we propose a new objective measure: the scaled signal intensity (SSI) of uterine fibroids in T2 weighted MR images (T2WI). Forty three uterine fibroids in 40 premenopausal women were included in this retrospective study. SSI of each fibroid was measured from the screening T2WI by standardizing its mean signal intensity to a 0-100 scale, using reference intensities of rectus abdominis muscle (0) and subcutaneous fat (100). Correlation between the SSI and the non-perfused volume (NPV) ratio (a measure for treatment success) was calculated. Pre-treatment SSI showed a significant inverse-correlation with post treatment NPV ratio (p < 0.05). When dichotomizing NPV ratio at 45 %, the optimal cut off value of the SSI was found to be 16.0. A fibroid with SSI value 16.0 or less can be expected to have optimal responses. The SSI of uterine fibroids in T2WI can be suggested as an objective parameter to help in patient selection for MRgFUS. (orig.)

  15. Scaled signal intensity of uterine fibroids based on T2-weighted MR images: a potential objective method to determine the suitability for magnetic resonance-guided focused ultrasound surgery of uterine fibroids.

    Science.gov (United States)

    Park, Hyun; Yoon, Sang-Wook; Sokolov, Amit

    2015-12-01

    Magnetic Resonance-guided Focused Ultrasound Surgery (MRgFUS) is a non-invasive method to treat uterine fibroids. To help determine the patient suitability for MRgFUS, we propose a new objective measure: the scaled signal intensity (SSI) of uterine fibroids in T2 weighted MR images (T2WI). Forty three uterine fibroids in 40 premenopausal women were included in this retrospective study. SSI of each fibroid was measured from the screening T2WI by standardizing its mean signal intensity to a 0-100 scale, using reference intensities of rectus abdominis muscle (0) and subcutaneous fat (100). Correlation between the SSI and the non-perfused volume (NPV) ratio (a measure for treatment success) was calculated. Pre-treatment SSI showed a significant inverse-correlation with post treatment NPV ratio (p < 0.05). When dichotomizing NPV ratio at 45 %, the optimal cut off value of the SSI was found to be 16.0. A fibroid with SSI value 16.0 or less can be expected to have optimal responses. The SSI of uterine fibroids in T2WI can be suggested as an objective parameter to help in patient selection for MRgFUS. • Signal intensity of fibroid in MR images predicts treatment response to MRgFUS. • Signal intensity is standardized into scaled form using adjacent tissues as references. • Fibroids with SSI less than 16.0 are expected to have optimal responses.

  16. Future potential of MRI-guided focused ultrasound brain surgery.

    Science.gov (United States)

    Colen, Rivka R; Jolesz, Ferenc A

    2010-08-01

    Magnetic resonance image-guided focused ultrasound surgery (MRgFUS) has surfaced as a viable noninvasive image-guided therapeutic method that integrates focused ultrasound (FUS), the therapeutic component, with magnetic resonance imaging (MRI), the image guidance module, into a real-time therapy delivery system with closed-loop control of energy delivery. The main applications for MRgFUS of the brain are thermal ablations for brain tumors and functional neurosurgery, and nonthermal, nonablative uses for disruption of the blood brain barrier (BBB) or blood clot and hematoma dissolution by liquification. The disruption of the BBB by FUS can be used for targeted delivery of chemotherapy and other therapeutic agents. MRI is used preoperatively for target definition and treatment planning, intraoperatively for procedure monitoring and control, and postoperatively for validating treatment success. Although challenges still remain, this integrated noninvasive therapy delivery system is anticipated to change current treatment paradigms in neurosurgery and the clinical neurosciences. Copyright 2010 Elsevier Inc. All rights reserved.

  17. WE-EF-BRA-12: Magnetic Resonance- Guided High-Intensity Focused Ultrasound for Localized Ablation of Head and Neck Tissue Structures: A Feasibility Study in An Animal Model

    Energy Technology Data Exchange (ETDEWEB)

    Partanen, A [Philips Healthcare, Andover, Massachusets (United States); Ellens, N; Noureldine, S; Tufano, R [Johns Hopkins University School of Medicine, Baltimore, MD (United States); Burdette, E [Acoustic MedSystems Inc., Savoy, IL (United States); Farahani, K [National Cancer Institute, Bethesda, MD (United States)

    2015-06-15

    Purpose: High-intensity focused ultrasound (HIFU) ablation is feasible in the head and neck [1]. This study aims to expand upon these findings to assess the feasibility of treatment planning and monitoring via magnetic resonance imaging (MRI) guidance using a clinical MR-guided HIFU platform. Methods: Two 31 kg pigs were anaesthetized, shaved, and positioned prone on the HIFU table (Sonalleve, Philips Healthcare, Vantaa, Finland). The necks were acoustically coupled to the integrated transducer using gel pads and degassed water. MR imaging verified acoustic coupling and facilitated target selection in the thyroid and thymus. Targets were thermally ablated with 130–200 W of acoustic power over a period of 16 s at a frequency of 1.2 MHz while being monitored through real-time, multi-planar MR-thermometry. Contrast-enhanced MR imaging was used to assess treatment efficacy. Post-treatment, animals were euthanized and sonicated tissues were harvested for histology assessment. Results: MR-thermometry, post-contrast-imaging, and gross pathology demonstrated that the system was capable of causing localized thermal ablation in both the thyroid and the thymus without damaging the aerodigestive tract. In one animal, superficial bruising was observed in the ultrasound beam path. Otherwise, there were no adverse events. Analysis of the tissue histology found regions of damage consistent with acute thermal injury at the targeted locations. Conclusion: It is feasible to use a clinical MR-guided HIFU platform for extracorporeal ablation of porcine head and neck tissues. MR guidance and thermometry are sufficient to target and monitor treatment in the thyroid region, despite the presence of the inhomogeneous aerodigestive tract. Further study is necessary to assess efficacy and survival using a tumor model, and to examine what modifications should be made to the transducer positioning system and associated patient positioning aids to adapt it for clinical head and neck targets

  18. Magnetic resonance-guided prostate interventions.

    Science.gov (United States)

    Haker, Steven J; Mulkern, Robert V; Roebuck, Joseph R; Barnes, Agnieska Szot; Dimaio, Simon; Hata, Nobuhiko; Tempany, Clare M C

    2005-10-01

    We review our experience using an open 0.5-T magnetic resonance (MR) interventional unit to guide procedures in the prostate. This system allows access to the patient and real-time MR imaging simultaneously and has made it possible to perform prostate biopsy and brachytherapy under MR guidance. We review MR imaging of the prostate and its use in targeted therapy, and describe our use of image processing methods such as image registration to further facilitate precise targeting. We describe current developments with a robot assist system being developed to aid radioactive seed placement.

  19. In Focus: Alcohol and Alcoholism Audiovisual Guide.

    Science.gov (United States)

    National Clearinghouse for Alcohol Information (DHHS), Rockville, MD.

    This guide reviews audiovisual materials currently available on alcohol abuse and alcoholism. An alphabetical index of audiovisual materials is followed by synopses of the indexed materials. Information about the intended audience, price, rental fee, and distributor is included. This guide also provides a list of publications related to media…

  20. MRI-guided High-Intensity Focused Ultrasound of Breast Cancer

    NARCIS (Netherlands)

    Merckel, L.G.

    2014-01-01

    Magnetic resonance imaging-guided high-intensity focused ultrasound (MR-HIFU) is a promising technique for completely noninvasive tumor ablation. This thesis focuses on its application for the treatment of patients with breast cancer. The first part of the thesis describes the role of breast MRI for

  1. Clinical outcome of magnetic-resonance-guided focused ultrasound surgery (MRgFUS) in the treatment of symptomatic uterine fibroids; Klinische Ergebnisse der Behandlung symptomatischer Uterusmyome mittels MRgFUS (Magnetresonanztomografie-gesteuerter fokussierter Ultraschall)

    Energy Technology Data Exchange (ETDEWEB)

    Kamp, J.E.K.; Scheurig-Muenkler, C.; Beck, A. [Charite - Universitaetsmedizin Berlin (Germany). Klinik fuer Radiologie; David, M. [Charite - Universitaetsmedizin Berlin (Germany). Klinik fuer Gynaekologie; Hengst, S. [Klinikum Barnim GmbH, Werner Forssmann Krankenhaus, Eberswalde (Germany). Klinik fuer Radiologie

    2013-02-15

    Purpose: To investigate the clinical outcome of magnetic-resonance-guided focused ultrasound surgery (MRgFUS) treatment for symptomatic uterine fibroids in premenopausal women using the validated USF-QOL (Uterine Fibroid Symptom and Quality of Life) Questionnaire. Materials and Methods: 54 patients with symptomatic uterine fibroids were enrolled in this prospective study. The patients completed the UFS-QOL Questionnaire prior to MRgFUS treatment as well as after 3, 6, and 12 months. Results: The rate of technical success was 91.5 % (95.2 % after subtraction of screening errors). 6/54 patients (11 %) had other treatments (surgery, n = 4; UAE, n = 2), 8/54 (15 %) dropped out due to pregnancy, and 8/54 were lost to follow-up. The remaining group showed considerable symptom relief as early as after 3 months. The median overall quality of life score increased from 64.7 (quartile range QR: 49.8 - 77.6) before treatment to 77.6 (QR: 61.4 - 87.1) (p < 0.001), 78.4 (QR: 66.4 - 89.7) (p < 0.001), and 82.8 (QR: 69.8 - 92.2) (p < 0.001) at 3, 6, and 12 months, respectively. The corresponding median symptom severity score decreased from 46.9 (QR: 28.1 - 56.2) to 34.4 (QR: 21.9 - 43.7) at 3 months (p = 0.003) and 28.1 at 6 and 12 months (QR: 18.7 - 38.3, QR: 15.6 - 34.4) (p < 0.001, p = 0.002). The rate of complications requiring treatment was 9 %, and the rate of overall complications was 39 %. No major complications occurred. Conclusion: Our results indicate significant alleviation of fibroid-related symptoms within 12 months of MRgFUS with improvement beginning as early as 3 months after treatment. We observed no major complications, and some women became pregnant after MRgFUS. There was a low treatment failure rate of 11 %. (orig.)

  2. Preliminary experience with a transcranial magnetic resonance-guided focused ultrasound surgery system integrated with a 1.5-T MRI unit in a series of patients with essential tremor and Parkinson's disease.

    Science.gov (United States)

    Iacopino, Domenico Gerardo; Gagliardo, Cesare; Giugno, Antonella; Giammalva, Giuseppe Roberto; Napoli, Alessandro; Maugeri, Rosario; Graziano, Francesca; Valentino, Francesca; Cosentino, Giuseppe; D'Amelio, Marco; Bartolotta, Tommaso Vincenzo; Catalano, Carlo; Fierro, Brigida; Midiri, Massimo; Lagalla, Roberto

    2018-02-01

    OBJECTIVE Transcranial magnetic resonance-guided focused ultrasound surgery (tcMRgFUS) is one of the emerging noninvasive technologies for the treatment of neurological disorders such as essential tremor (ET), idiopathic asymmetrical tremor-dominant Parkinson's disease (PD), and neuropathic pain. In this clinical series the authors present the preliminary results achieved with the world's first tcMRgFUS system integrated with a 1.5-T MRI unit. METHODS The authors describe the results of tcMRgFUS in a sample of patients with ET and with PD who underwent the procedure during the period from January 2015 to September 2017. A monolateral ventralis intermedius nucleus (VIM) thalamic ablation was performed in both ET and PD patients. In all the tcMRgFUS treatments, a 1.5-T MRI scanner was used for both planning and monitoring the procedure. RESULTS During the study period, a total of 26 patients underwent tcMRgFUS thalamic ablation for different movement disorders. Among these patients, 18 were diagnosed with ET and 4 were affected by PD. All patients with PD were treated using tcMRgFUS thalamic ablation and all completed the procedure. Among the 18 patients with ET, 13 successfully underwent tcMRgFUS, 4 aborted the procedure during ultrasound delivery, and 1 did not undergo the tcMRgFUS procedure after stereotactic frame placement. Two patients with ET were not included in the results because of the short follow-up duration at the time of this study. A monolateral VIM thalamic ablation in both ET and PD patients was performed. All the enrolled patients were evaluated before the treatment and 2 days after, with a clinical control of the treatment effectiveness using the graphic items of the Fahn-Tolosa-Marin tremor rating scale. A global reevaluation was performed 3 months (17/22 patients) and 6 months (11/22 patients) after the treatment; the reevaluation consisted of clinical questionnaires, neurological tests, and video recordings of the tests. All the ET and PD

  3. MR-guided focused ultrasound: a potentially disruptive technology.

    Science.gov (United States)

    Bradley, William G

    2009-07-01

    A disruptive technology is a technological innovation that overturns the existing dominant technologies in a market. Magnetic resonance (MR)-guided focused ultrasound (MRgFUS) is a noninvasive procedure based on the combination of real-time MR anatomic guidance, MR thermometry, and high-intensity focused ultrasound. Several hundred transducer elements become convergent at a point under MR guidance, leading to heating and coagulation necrosis. Outside the focal point, there is no significant heating. There is no need to break the skin for procedures in the body or to perform a craniotomy for procedures in the brain. This lack of invasiveness is what makes MRgFUS so disruptive compared with surgery. At present, MRgFUS has been used for the ablation of uterine fibroids, breast tumors, painful bony metastases, and liver tumors. In the brain, it has been used for the ablation of glioblastomas and for functional neurosurgery. Phantom and animal studies suggest future applications for prostate cancer and acute stroke treatment.

  4. Review of MRI positioning devices for guiding focused ultrasound systems.

    Science.gov (United States)

    Yiallouras, C; Damianou, C

    2015-06-01

    This article contains a review of positioning devices that are currently used in the area of magnetic resonance imaging (MRI) guided focused ultrasound surgery (MRgFUS). The paper includes an extensive review of literature published since the first prototype system was invented in 1991. The technology has grown into a fast developing area with application to any organ accessible to ultrasound. The initial design operated using hydraulic principles, while the latest technology incorporates piezoelectric motors. Although, in the beginning there were fears regarding MRI safety, during recent years, the deployment of MR-safe positioning devices in FUS has become routine. Many of these positioning devices are now undergoing testing in clinical trials. Existing MRgFUS systems have been utilized mostly in oncology (fibroids, brain, liver, kidney, bone, pancreas, eye, thyroid, and prostate). It is anticipated that, in the near future, there will be a positioning device for every organ that is accessible by focused ultrasound. Copyright © 2014 John Wiley & Sons, Ltd.

  5. Towards MR-guided high intensity focused ultrasound ablation of liver tumors

    NARCIS (Netherlands)

    Wijlemans, J.W.

    2015-01-01

    Magnetic Resonance-guided High Intensity Focused Ultrasound (MR-HIFU) is a promising technique which can be used for completely non-invasive tissue ablation. The converging ultrasound beam penetrates the skin and subcutaneous tissues with damage, while heating the tissue only in the focal point. The

  6. Facile synthesis of magnetite/perfluorocarbon co-loaded organic/inorganic hybrid vesicles for dual-modality ultrasound/magnetic resonance imaging and imaging-guided high-intensity focused ultrasound ablation.

    Science.gov (United States)

    Niu, Dechao; Wang, Xia; Li, Yongsheng; Zheng, Yuanyi; Li, Faqi; Chen, Hangrong; Gu, Jinlou; Zhao, Wenru; Shi, Jianlin

    2013-05-21

    Multifunctional organic/inorganic hybrid nanovesicles, fabricated by a facile self-assembly/sol-gel approach, display a unique morphology (figure) and satisfactory stability under physiological conditions. By co-encapsulation of superparamagnetic magnetite nanoparticles and a liquid perfluorocarbon, the nanovesicles can be used not only as a dual-modality ultrasound/magnetic resonance contrast agent for accurate cancer diagnosis and monitoring, but also as a therapeutic enhancement agent for effective high-intensity focused ultrasound (HIFU) ablation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Magnetic resonance-guided interventions of large and small joints.

    Science.gov (United States)

    Garmer, Marietta; Grönemeyer, Dietrich

    2011-08-01

    Magnetic resonance (MR)-guided interventions of large and small joints are feasible and safe procedures offering several advantages compared with standard guiding techniques. Nevertheless, MR-guided interventions are not routinely performed in daily practice apart from a few centers. Accurate injections are crucial for clinical outcome in diagnostic arthrography as well as therapeutic joint injections. In particular, palpatory joint puncture was shown to be inaccurate or uncertain in a substantial percentage of injections of the shoulder, the hip, and the knee. Magnetic resonance imaging offers respective merits of a cross-sectional technique with high soft-tissue contrast. Exact depiction of structures, which should be preserved, such as the labrum, should be aimed for. Areas with complex anatomy can be approached by adapting the right imaging plane(s) because of multiplanar capacity. Lack of ionizing radiation for patients is of growing interest particularly in young patients with repeated interventions. Magnetic resonance guidance alone allows an "all-in-one" MR arthrography combining precise targeting with high-field-strength imaging. Modern short-bore and open-bore high-field-strength systems offer a good comfort for patients as well as clinicians and enhance patient positioning options such as supine or prone position. Thus, a tailored approach such as a posterior technique for suspected anterior lesions in shoulder MR arthrography is possible.In this article, we describe the advantages and limitations of MR guidance in joint interventions with focus on shoulder and hip interventions. We review the requirements for needle material and MR sequences, discuss several different techniques developed to date, and present current results in clinical outcome.

  8. Design and tests of an adaptive focusing neutron guide

    Energy Technology Data Exchange (ETDEWEB)

    Valicu, Roxana Georgiana

    2012-08-23

    This work contains the Monte Carlo Simulations, as well as the first tests with an adaptive focusing neutron guide for creating a focus that does not depend on the wavelength of the incoming neutrons. All known neutron guides consist of a rectangular shape, built out of four glass plates. The inner side of the guide is coated with a complex structure of metal layers. This reflects and guides the neutrons (in analogy with the reflection of the light). For beam focusing neutron guides with fixed curvature can be built. For most experiments it is important that the beam is focused on to a small surface of the sample. In the case of focusing guides with fixed curvature it has been observed that the focusing (dimension and position of the beam focus) is wavelength dependent. This is why for measurements that are performed with different wavelengths it is very important to change the curvature of the neutron guide in order to obtain optimal results. In this work we have designed, constructed and tested a guide where we can change the curvature during the experiment. In this way we can obtain a variable curvature in horizontal as well as in vertical direction. For a curvature in the horizontal or vertical direction it is not necessary to move all four walls, only two of the opposed plates. The element that changes the curvature of the guide consists of an acting element (piezomotor) as well as a rod that can be operated by the piezomotor and that acts through a lever onto the plate. The action of a force and a consecutive torsion momentum at the free end of the plate changes the curvature of the whole plate in an almost parabolic way. Making use of the Monte Carlo simulations we were able to determine the optimal curvature for each wavelength of a neutron guide for the spectrometer TOFTOF installed at the Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II). First tests have shown that with an adaptive focusing guide one can gain up to a factor three in intensity at

  9. MR-Guided High-Intensity Focused Ultrasound: Current Status of an Emerging Technology

    Energy Technology Data Exchange (ETDEWEB)

    Napoli, Alessandro, E-mail: napoli.alessandro@gmail.com; Anzidei, Michele, E-mail: michele.anzidei@gmail.com; Ciolina, Federica, E-mail: federica.ciolina@gmail.com; Marotta, Eugenio, E-mail: eugenio.marotta@gmail.com; Cavallo Marincola, Beatrice, E-mail: beatrice.cavalloamarincola@gmail.com; Brachetti, Giulia, E-mail: giuliabrachetti@gmail.com; Mare, Luisa Di, E-mail: luisadimare@gmail.com; Cartocci, Gaia, E-mail: gaia.cartocci@gmail.com; Boni, Fabrizio, E-mail: fabrizioboni00@gmail.com; Noce, Vincenzo, E-mail: vinc.noce@hotmail.it; Bertaccini, Luca, E-mail: lucaone84@libero.it; Catalano, Carlo, E-mail: carlo.catalano@uniroma1.it [Sapienza, University of Rome, Department of Radiological Sciences (Italy)

    2013-10-15

    The concept of ideal tumor surgery is to remove the neoplastic tissue without damaging adjacent normal structures. High-intensity focused ultrasound (HIFU) was developed in the 1940s as a viable thermal tissue ablation approach. In clinical practice, HIFU has been applied to treat a variety of solid benign and malignant lesions, including pancreas, liver, prostate, and breast carcinomas, soft tissue sarcomas, and uterine fibroids. More recently, magnetic resonance guidance has been applied for treatment monitoring during focused ultrasound procedures (magnetic resonance-guided focused ultrasound, MRgFUS). Intraoperative magnetic resonance imaging provides the best possible tumor extension and dynamic control of energy deposition using real-time magnetic resonance imaging thermometry. We introduce the fundamental principles and clinical indications of the MRgFUS technique; we also report different treatment options and personal outcomes.

  10. Resonant excess quantum noise in lasers with mixed guiding

    NARCIS (Netherlands)

    Lien, Y.; van der Togt, E.; van Exter, M.P.; Woerdman, J.P.; van Druten, N.J.

    2003-01-01

    We show experimentally that the combination of soft-edged gain and index guiding can lead to resonant excess quantum noise. Resonances with excess noise factors close to 100 are observed in end-pumped Nd 3+ YVO 4 lasers for cavity lengths in which two modes experience similar gain. An associated

  11. Characteristics of Resonantly-Guided Modes in Microstructured Optical Fibers

    Directory of Open Access Journals (Sweden)

    Yasuo Ohtera

    2014-11-01

    Full Text Available Modal characteristics of resonantly-guided modes (RGMs in microstructured fibers were investigated through numerical simulation. The modes of interest are supported in a class of fibers consisting of a circularly arranged periodic array of high index rods embedded in a low index cladding. Light is confined and guided by the guided-mode resonance (GMR that the rod array exhibit. According to the numerical analysis we clarified that duplicated transverse modes having the same radial mode number for TM and TE modes were supported. Also the existence and detailed mode profiles of hybrid modes were confirmed.

  12. Wave power focusing due to the Bragg resonance

    Science.gov (United States)

    Tao, Ai-feng; Yan, Jin; Wang, Yi; Zheng, Jin-hai; Fan, Jun; Qin, Chuan

    2017-08-01

    Wave energy has drawn much attention as an achievable way to exploit the renewable energy. At present, in order to enhance the wave energy extraction, most efforts have been concentrated on optimizing the wave energy convertor and the power take-off system mechanically and electrically. However, focusing the wave power in specific wave field could also be an alternative to improve the wave energy extraction. In this experimental study, the Bragg resonance effect is applied to focus the wave energy. Because the Bragg resonance effect of the rippled bottom largely amplifies the wave reflection, leading to a significant increase of wave focusing. Achieved with an energy conversion system consisting of a point absorber and a permanent magnet single phase linear motor, the wave energy extracted in the wave flume with and without Bragg resonance effect was measured and compared quantitatively in experiment. It shows that energy extraction by a point absorber from a standing wave field resulted from Bragg resonance effect can be remarkably increased compared with that from a propagating wave field (without Bragg resonance effect).

  13. Systematic study on the performance of elliptic focusing neutron guides

    Energy Technology Data Exchange (ETDEWEB)

    Martin Rodriguez, D., E-mail: damian.rodriguez@esss.se [European Spallation Source ERIC, Box 176, 221 00 Lund (Sweden); DiJulio, D.D. [European Spallation Source ERIC, Box 176, 221 00 Lund (Sweden); Department of Physics, Lund University, SE-221 00 Lund (Sweden); Bentley, P.M. [European Spallation Source ERIC, Box 176, 221 00 Lund (Sweden); Department of Physics and Astronomy, University of Uppsala, Uppsala 751 20 (Sweden)

    2016-02-01

    In neutron scattering experiments there is an increasing trend towards the study of smaller volume samples, which make the use of focusing optics more important. Focusing guide geometries based on conic-sections, such as those with parabolic and elliptic shapes, have been extensively used in both recently built neutron instruments and upgrades of existing hardware. A large fraction of proposed instruments at the European Spallation Source feature the requirement of good performance when measuring on small samples. The optimised design of a focusing system comes after time consuming Monte-Carlo (MC) simulations. Therefore, in order to help reduce the time needed to design such focusing systems, it is necessary to study systematically the performance of focusing guides. In the present work, we perform a theoretical analysis of the focusing properties of neutron beams, and validate them using a combination of Monte-Carlo simulations and Particle Swarm Optimisations (PSOs), where there is a close correspondence between the maximum divergence of the beam and the shape of the guide. The analytical results show that two limits can be considered, which bound a range of conic section shapes that provide optimum performance. Finally, we analyse a more realistic guide example and we give an assessment of the importance of the contribution from multiple reflections in different systems.

  14. MR-Guided Focused Ultrasound for the Treatment of Uterine Fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Hesley, Gina K.; Gorny, Krzysztof R.; Woodrum, David A., E-mail: woodrum.david@mayo.edu [Mayo Clinic College of Medicine, Department of Radiology (United States)

    2013-02-15

    Magnetic resonance imaging-guided focused ultrasound (MRgFUS) ablation of uterine fibroids provides a minimally invasive outpatient technique for targeting and treating symptomatic uterine fibroids. Magnetic resonance imaging provides a guidance platform that has high temporal and spatial resolution for guiding, as well as thermal monitoring of the procedure. The high-intensity focused ultrasound provides a mechanism for delivering large amounts of energy directly into the fibroid without causing detrimental effects to the nontarget tissues. Early and intermediate follow-up of patients treated with MRgFUS provided promising results on the efficacy of the technique for providing symptom relief to patients. As more long-term follow-up data are published, the efficacy of this technique can be compared to more invasive surgical and minimally invasive catheter treatments.

  15. Electrothermally actuated tunable clamped-guided resonant microbeams

    KAUST Repository

    Alcheikh, Nouha

    2017-06-11

    We present simulation and experimental investigation demonstrating active alteration of the resonant and frequency response behavior of resonators by controlling the electrothermal actuation method on their anchors. In-plane clamped-guided arch and straight microbeams resonators are designed and fabricated with V-shaped electrothermal actuators on their anchors. These anchors not only offer various electrothermal actuation options, but also serve as various mechanical stiffness elements that affect the operating resonance frequency of the structures. We have shown that for an arch, the first mode resonance frequency can be increased up to 50% of its initial value. For a straight beam, we have shown that before buckling, the resonance frequency decreases to very low values and after buckling, it increases up to twice of its initial value. These results can be promising for the realization of different wide–range tunable microresonator. The experimental results have been compared to multi-physics finite-element simulations showing good agreement among them.

  16. Electrothermally actuated tunable clamped-guided resonant microbeams

    Science.gov (United States)

    Alcheikh, N.; Hajjaj, A. Z.; Jaber, N.; Younis, M. I.

    2018-01-01

    We present simulation and experimental investigation demonstrating active alteration of the resonant and frequency response behavior of resonators by controlling the electrothermal actuation method on their anchors. In-plane clamped-guided arch and straight microbeams resonators are designed and fabricated with V-shaped electrothermal actuators on their anchors. These anchors not only offer various electrothermal actuation options, but also serve as various mechanical stiffness elements that affect the operating resonance frequency of the structures. We have shown that for an arch, the first mode resonance frequency can be increased up to 50% of its initial value. For a straight beam, we have shown that before buckling, the resonance frequency decreases to very low values and after buckling, it increases up to twice of its initial value. These results can be promising for the realization of different wide-range tunable microresonator. The experimental results have been compared to multi-physics finite-element simulations showing good agreement among them.

  17. Focusing guided waves using surface bonded elastic metamaterials

    Science.gov (United States)

    Yan, Xiang; Zhu, Rui; Huang, Guoliang; Yuan, Fuh-Gwo

    2013-09-01

    Bonding a two-dimensional planar array of small lead discs on an aluminum plate with silicone rubber is shown numerically to focus low-frequency flexural guided waves. The "effective mass density profile" of this type of elastic metamaterials (EMMs), perpendicular to wave propagation direction, is carefully tailored and designed, which allows rays of flexural A0 mode Lamb waves to bend in succession and then focus through a 7 × 9 planar array. Numerical simulations show that Lamb waves can be focused beyond EMMs region with amplified displacement and yet largely retained narrow banded waveform, which may have potential application in structural health monitoring.

  18. Absolute analytical prediction of photonic crystal guided mode resonance wavelengths

    DEFF Research Database (Denmark)

    Hermannsson, Pétur Gordon; Vannahme, Christoph; Smith, Cameron

    2014-01-01

    A class of photonic crystal resonant reflectors known as guided mode resonant filters are optical structures that are widely used in the field of refractive index sensing, particularly in biosensing. For the purposes of understanding and design, their behavior has traditionally been modeled...... numerically with methods such as rigorous coupled wave analysis. Here it is demonstrated how the absolute resonance wavelengths of such structures can be predicted by analytically modeling them as slab waveguides in which the propagation constant is determined by a phase matching condition. The model...

  19. Magnetic-resonance-guided biopsy of focal liver lesions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Ethan A. [University of Michigan Health System, Section of Pediatric Radiology, C.S. Mott Children' s Hospital, Department of Radiology, Ann Arbor, MI (United States); Grove, Jason J. [University of Michigan Health System, Division of Interventional Radiology, C.S. Mott Children' s Hospital, Department of Radiology, Ann Arbor, MI (United States); Der Spek, Abraham F.L.V. [University of Michigan Health System, Department of Anesthesiology, C.S. Mott Children' s Hospital, Ann Arbor, MI (United States); Jarboe, Marcus D. [University of Michigan Health System, Division of Interventional Radiology, C.S. Mott Children' s Hospital, Department of Radiology, Ann Arbor, MI (United States); University of Michigan Health System, Section of Pediatric Surgery, C.S. Mott Children' s Hospital, Department of Surgery, Ann Arbor, MI (United States)

    2017-05-15

    Image-guided biopsy techniques are widely used in clinical practice. Commonly used methods employ either ultrasound (US) or computed tomography (CT) for image guidance. In certain patients, US or CT guidance may be suboptimal, or even impossible, because of artifacts, suboptimal lesion visualization, or both. We recently began performing magnetic resonance (MR)-guided biopsy of focal liver lesions in select pediatric patients with lesions that are not well visualized by US or CT. This report describes our experience performing MR-guided biopsy of focal liver lesions, with case examples to illustrate innovative techniques and novel aspects of these procedures. (orig.)

  20. Noninvasive functional neurosurgery using transcranial MR imaging-guided focused ultrasound.

    Science.gov (United States)

    Bauer, Ronald; Martin, Ernst; Haegele-Link, Stefan; Kaegi, Georg; von Specht, Moritz; Werner, Beat

    2014-01-01

    Transcranial magnetic resonance imaging-guided focused ultrasound (tcMRgFUS) is a novel technique to supplement the spectrum of established neurosurgical interventions. In contrast to traditional ablative procedures, tcMRgFUS is noninvasive and entirely imaging-guided with continuous temperature measurements at and around the target in real time. It has no trajectory restrictions and does not involve ionizing radiation. Since no device is implanted into the brain or the body, there is no restriction to future diagnostic work-up with MR imaging. The ability to treat a variety of chronic, therapy-resistant neurological diseases by precisely focusing ultrasound energy to desired targets in the thalamus, subthalamus and basal ganglia while avoiding collateral tissue damage is certainly attractive. Ongoing clinical studies on over 130 patients with neuropathic pain, essential tremor, Parkinson's disease and obsessive-compulsive disorder are very promising and demonstrate that ultrasound energy can precisely be focused through the intact skull, without overheating it. Varying the ultrasound parameters allows not only to ablate pathological tissue, or silence dysfunctional neuronal circuits, but also to modulate neural functions, as shown in preclinical studies. Transcranial magnetic resonance imaging-guided focused ultrasound is a novel, noninvasive, alternative treatment option for patients with therapy-resistant movement disorders, such as essential tremor and Parkinson's disease. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Optical phased array using guided resonance with backside reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Horie, Yu; Arbabi, Amir; Faraon, Andrei

    2016-11-01

    Methods and systems for controlling the phase of electromagnetic waves are disclosed. A device can consist of a guided resonance grating layer, a spacer, and a reflector. A plurality of devices, arranged in a grid pattern, can control the phase of reflected electromagnetic phase, through refractive index control. Carrier injection, temperature control, and optical beams can be applied to control the refractive index.

  2. Noninvasive treatment of focal adenomyosis with MR-guided focused ultrasound in two patients

    Directory of Open Access Journals (Sweden)

    Laveena Polina

    2012-01-01

    Full Text Available Adenomyosis is a common benign gynecological disorder presenting with dysmenorrhea, menorrhagia, and pressure symptoms. Magnetic resonance imaging-guided focused ultrasound surgery (MRgFUS utilizes precisely focused USG waves to generate and maintain high temperatures within the targeted tissue to achieve protein denaturation and coagulative necrosis. The heat generated is monitored using MRI images acquired in real-time in three planes. We present two cases of focal adenomyosis treated with MRgFUS showing good symptomatic relief at 3 and 6 months follow-up.

  3. MRI guided focused ultrasound robotic system for animal experiments.

    Science.gov (United States)

    Yiannakou, Marinos; Menikou, Georgios; Yiallouras, Christos; Ioannides, Cleanthis; Damianou, Christakis

    2017-12-01

    In this paper an MRI-guided focused ultrasound (MRgFUS) robotic system was developed that can be used for conducting experiments in small animals.The target for this robotic system regarding motion was to move a therapeutic ultrasound transducer in two Cartesian axes. A single element spherically focused transducer of 3 cm diameter, focusing at 7 cm and operating at 0.4 MHz was used. The positioning device incorporates only MRI compatible materials. The propagation of ultrasound is a bottom to top approach. The 2-D positioning device is controlled by custom-made software and a custom-made electronic system which controls the two piezoelectric motors. The system was tested successfully in agar/silica/evaporated milk phantom for various tasks (robot motion, MR compatibility, and MR thermometry). The robotic system is capable of moving the focused ultrasound transducer to perform MR-guided focused ultrasound experiments in small animals. This system has the potential to be deployed as a cost effective solution for performing experiments in small animals. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Targeted delivery of GDNF through the blood-brain barrier by MRI-guided focused ultrasound.

    Directory of Open Access Journals (Sweden)

    Feng Wang

    Full Text Available Neurotrophic factors, such as glial cell line-derived neurotrophic factor (GDNF, are promising therapeutic agents for neurodegenerative diseases. However, the application of GDNF to treat these diseases effectively is limited because the blood-brain barrier (BBB prevents the local delivery of macromolecular therapeutic agents from entering the central nervous system (CNS. Focused ultrasound combined with microbubbles (MBs using appropriate parameters has been previously demonstrated to be able to open the BBB locally and noninvasively. This study investigated the targeted delivery of GDNF MBs through the BBB by magnetic resonance imaging (MRI-guided focused ultrasound. Evans Blue extravasation and histological examination were used to determine the optimum focused ultrasound parameters. Enzyme-linked immunosorbent assay was performed to verify the effects of GDNF bound on MBs using a biotin-avidin bridging chemistry method to promote GDNF delivery into the brain. The results showed that GDNF can be delivered locally and noninvasively into the CNS through the BBB using MRI-guided focused ultrasound combined with MBs under optimum parameters. MBs that bind GDNF combined with MRI-guided focused ultrasound may be an effective way of delivering neurotrophic factors directly into the CNS. The method described herein provides a potential means of treating patients with CNS diseases.

  5. A framework for continuous target tracking during MR-guided high intensity focused ultrasound thermal ablations in the abdomen

    NARCIS (Netherlands)

    Zachiu, Cornel; Denis de Senneville, Baudouin; Dmitriev, Ivan D.; Moonen, Chrit T.W.; Ries, Mario

    2017-01-01

    Background: During lengthy magnetic resonance-guided high intensity focused ultrasound (MRg-HIFU) thermal ablations in abdominal organs, the therapeutic work-flow is frequently hampered by various types of physiological motion occurring at different time-scales. If left un-addressed this can lead to

  6. Absolute analytical prediction of photonic crystal guided mode resonance wavelengths

    Energy Technology Data Exchange (ETDEWEB)

    Hermannsson, Pétur Gordon; Vannahme, Christoph; Smith, Cameron L. C.; Kristensen, Anders, E-mail: anders.kristensen@nanotech.dtu.dk [Department of Micro- and Nanotechnology, Technical University of Denmark, Ørsteds Plads, Building 345E, DK-2800 Kgs. Lyngby (Denmark)

    2014-08-18

    A class of photonic crystal resonant reflectors known as guided mode resonant filters are optical structures that are widely used in the field of refractive index sensing, particularly in biosensing. For the purposes of understanding and design, their behavior has traditionally been modeled numerically with methods such as rigorous coupled wave analysis. Here it is demonstrated how the absolute resonance wavelengths of such structures can be predicted by analytically modeling them as slab waveguides in which the propagation constant is determined by a phase matching condition. The model is experimentally verified to be capable of predicting the absolute resonance wavelengths to an accuracy of within 0.75 nm, as well as resonance wavelength shifts due to changes in cladding index within an accuracy of 0.45 nm across the visible wavelength regime in the case where material dispersion is taken into account. Furthermore, it is demonstrated that the model is valid beyond the limit of low grating modulation, for periodically discontinuous waveguide layers, high refractive index contrasts, and highly dispersive media.

  7. MR-guided focused ultrasound surgery, present and future

    Science.gov (United States)

    Schlesinger, David; Benedict, Stanley; Diederich, Chris; Gedroyc, Wladyslaw; Klibanov, Alexander; Larner, James

    2013-01-01

    MR-guided focused ultrasound surgery (MRgFUS) is a quickly developing technology with potential applications across a spectrum of indications traditionally within the domain of radiation oncology. Especially for applications where focal treatment is the preferred technique (for example, radiosurgery), MRgFUS has the potential to be a disruptive technology that could shift traditional patterns of care. While currently cleared in the United States for the noninvasive treatment of uterine fibroids and bone metastases, a wide range of clinical trials are currently underway, and the number of publications describing advances in MRgFUS is increasing. However, for MRgFUS to make the transition from a research curiosity to a clinical standard of care, a variety of challenges, technical, financial, clinical, and practical, must be overcome. This installment of the Vision 20/20 series examines the current status of MRgFUS, focusing on the hurdles the technology faces before it can cross over from a research technique to a standard fixture in the clinic. It then reviews current and near-term technical developments which may overcome these hurdles and allow MRgFUS to break through into clinical practice. PMID:23927296

  8. MR-guided focused ultrasound surgery, present and future

    Energy Technology Data Exchange (ETDEWEB)

    Schlesinger, David, E-mail: djs9c@virginia.edu [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 and Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia 22908 (United States); Benedict, Stanley [Department of Radiation Oncology, University of California Davis, Davis, California 95817 (United States); Diederich, Chris [Department of Radiation Oncology, University of California San Francisco, San Francisco, California 94115 (United States); Gedroyc, Wladyslaw [Department of Medicine, Imperial College, London SW7 2AZ (United Kingdom); Klibanov, Alexander [Departments of Medicine, Cardiovascular Medicine, and Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908 (United States); Larner, James [Department of Radiation Oncology, University of Virginia, Charlottesville, Virginia 22908 (United States)

    2013-08-01

    MR-guided focused ultrasound surgery (MRgFUS) is a quickly developing technology with potential applications across a spectrum of indications traditionally within the domain of radiation oncology. Especially for applications where focal treatment is the preferred technique (for example, radiosurgery), MRgFUS has the potential to be a disruptive technology that could shift traditional patterns of care. While currently cleared in the United States for the noninvasive treatment of uterine fibroids and bone metastases, a wide range of clinical trials are currently underway, and the number of publications describing advances in MRgFUS is increasing. However, for MRgFUS to make the transition from a research curiosity to a clinical standard of care, a variety of challenges, technical, financial, clinical, and practical, must be overcome. This installment of the Vision 20/20 series examines the current status of MRgFUS, focusing on the hurdles the technology faces before it can cross over from a research technique to a standard fixture in the clinic. It then reviews current and near-term technical developments which may overcome these hurdles and allow MRgFUS to break through into clinical practice.

  9. Resonant Orbital Dynamics in LEO Region: Space Debris in Focus

    Directory of Open Access Journals (Sweden)

    J. C. Sampaio

    2014-01-01

    Full Text Available The increasing number of objects orbiting the earth justifies the great attention and interest in the observation, spacecraft protection, and collision avoidance. These studies involve different disturbances and resonances in the orbital motions of these objects distributed by the distinct altitudes. In this work, objects in resonant orbital motions are studied in low earth orbits. Using the two-line elements (TLE of the NORAD, resonant angles and resonant periods associated with real motions are described, providing more accurate information to develop an analytical model that describes a certain resonance. The time behaviors of the semimajor axis, eccentricity, and inclination of some space debris are studied. Possible irregular motions are observed by the frequency analysis and by the presence of different resonant angles describing the orbital dynamics of these objects.

  10. Grating-based guided-mode resonance devices and degradation of their performance in real-life conditions

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Bergmann, René; Kafka, Jan Robert

    2014-01-01

    of an infinite periodic structure illuminated by a plane wave. To see how grating-based components can perform in real life we take into account two critical factors: the finite size of the grating and the Gaussian shape of the light source replacing a plane wave. These factors can significantly change...... and impair the performance of filters, mirrors, sensors and other devices operating by the guided-mode resonance effect. We also show experimentally that for some kinds of gratings guided-mode resonances can vanish if the grating is illuminated by extended source, i.e. heated plate in our case, focused...

  11. MR techniques for guiding high-intensity focused ultrasound (HIFU) treatments.

    Science.gov (United States)

    Kuroda, Kagayaki

    2018-02-01

    To make full use of the ability of magnetic resonance (MR) to guide high-intensity focused ultrasound (HIFU) treatment, effort has been made to improve techniques for thermometry, motion tracking, and sound beam visualization. For monitoring rapid temperature elevation with proton resonance frequency (PRF) shift, data acquisition and processing can be accelerated with parallel imaging and/or sparse sampling in conjunction with appropriate signal processing methods. Thermometry should be robust against tissue motion, motion-induced magnetic field variation, and susceptibility change. Thus, multibaseline, referenceless, or hybrid techniques have become important. In cases with adipose or bony tissues, for which PRF shift cannot be used, thermometry with relaxation times or signal intensity may be utilized. Motion tracking is crucial not only for thermometry but also for targeting the focus of an ultrasound in moving organs such as the liver, kidney, or heart. Various techniques for motion tracking, such as those based on an anatomical image atlas with optical-flow displacement detection, a navigator echo to seize the diaphragm position, and/or rapid imaging to track vessel positions, have been proposed. Techniques for avoiding the ribcage and near-field heating have also been examined. MR acoustic radiation force imaging (MR-ARFI) is an alternative to thermometry that can identify the location and shape of the focal spot and sound beam path. This technique could be useful for treating heterogeneous tissue regions or performing transcranial therapy. All of these developments, which will be discussed further in this review, expand the applicability of HIFU treatments to a variety of clinical targets while maintaining safety and precision. 2 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2018;47:316-331. © 2017 International Society for Magnetic Resonance in Medicine.

  12. Primary malignant tumours of the bony pelvis: US-guided high intensity focused ultrasound ablation.

    Science.gov (United States)

    Wang, Yang; Wang, Wei; Tang, Jie

    2013-11-01

    The aim of this review is to evaluate the value of ultrasound (US)-guided high intensity focused ultrasound (HIFU) ablation in the treatment of primary malignant tumours of the bony pelvis. Eleven patients with primary malignant tumours of the bony pelvis received US-guided HIFU ablation. The maximum tumour size ranged from 5.6 to 25.0 cm (median 10.5 cm). Treatment was curative in four patients and palliative in seven patients. During follow-up, the effectiveness of HIFU ablation was assessed by contrast-enhanced magnetic resonance (MR). Significant coagulative necrosis was obtained in all patients after scheduled HIFU ablations; the volume ablation ratio was 86.7% ± 12.5% (range 65-100%). Complete tumour necrosis was achieved in all patients receiving curative HIFU ablation. No major complications were encountered. No patients died of local tumour progression during follow-up. US-guided HIFU ablation may be a safe and effective minimally invasive technique for the local treatment of primary malignant tumours of the bony pelvis.

  13. Uterine Leiomyomas: MR Imaging–guided Focused Ultrasound Surgery—Imaging Predictors of Success

    Science.gov (United States)

    Lénárd, Zsuzsanna M.; McDannold, Nathan J.; Fennessy, Fiona M.; Stewart, Elizabeth A.; Jolesz, Ferenc A.; Hynynen, Kullervo; Tempany, Clare M. C.

    2008-01-01

    Purpose: To retrospectively assess the magnetic resonance (MR) imaging predictors of success at reducing uterine leiomyoma volume and achieving patient symptom relief 12 months after MR imaging–guided focused ultrasound surgery. Materials and Methods: This single-center retrospective analysis of 71 symptomatic fibroids in 66 women was approved by the institutional review board and was HIPAA-compliant. Patients were treated with MR imaging–guided focused ultrasound surgery. The volume of treated fibroid and nonperfused volume (NPV) were calculated with software, while symptom outcome was assessed with a symptom severity score (SSS). Fibroids were classified as hyperintense or hypointense relative to skeletal muscle on pretreatment T2-weighted MR images. Results: Baseline volume of treated fibroids was 255.5 cm3 ± 201.7 (standard deviation), and baseline SSS was 61.5 ± 14.9. Both pretreatment fibroid signal intensity (SI) and posttreatment NPV predicted 12-month volume reduction independently: Fibroids with an NPV of at least 20% or with low SI both showed significantly larger volume reduction (17.0% ± 13.0 and 17.2% ± 20.1, respectively) than fibroids with an NPV less than 20% or with high SI (10.7% ± 18.2 and no significant change, respectively). Patients whose fibroids demonstrated an NPV of at least 20% also experienced a larger decrease in SSS than did patients with fibroids with an NPV less than 20% (50.1% ± 19.8 vs 32.6% ± 29.9). Conclusion: Fibroids with low SI on pretreatment T2-weighted MR images were more likely to shrink than were ones with high SI. The larger the NPV immediately after treatment, the greater the volume reduction and symptom relief were. These findings may help both in selecting appropriate patients for MR-guided focused ultrasound surgery and in predicting patient outcome. © RSNA, 2008 PMID:18695211

  14. Magnetic resonance imaging of boiling induced by high intensity focused ultrasound

    Science.gov (United States)

    Khokhlova, Tatiana D.; Canney, Michael S.; Lee, Donghoon; Marro, Kenneth I.; Crum, Lawrence A.; Khokhlova, Vera A.; Bailey, Michael R.

    2009-01-01

    Both mechanically induced acoustic cavitation and thermally induced boiling can occur during high intensity focused ultrasound (HIFU) medical therapy. The goal was to monitor the temperature as boiling was approached using magnetic resonance imaging (MRI). Tissue phantoms were heated for 20 s in a 4.7-T magnet using a 2-MHz HIFU source with an aperture and radius of curvature of 44 mm. The peak focal pressure was 27.5 MPa with corresponding beam width of 0.5 mm. The temperature measured in a single MRI voxel by water proton resonance frequency shift attained a maximum value of only 73 °C after 7 s of continuous HIFU exposure when boiling started. Boiling was detected by visual observation, by appearance on the MR images, and by a marked change in the HIFU source power. Nonlinear modeling of the acoustic field combined with a heat transfer equation predicted 100 °C after 7 s of exposure. Averaging of the calculated temperature field over the volume of the MRI voxel (0.3×0.5×2 mm3) yielded a maximum of 73 °C that agreed with the MR thermometry measurement. These results have implications for the use of MRI-determined temperature values to guide treatments with clinical HIFU systems. PMID:19354416

  15. Imaging of pulmonary pathologies: focus on magnetic resonance imaging.

    Science.gov (United States)

    Kauczor, Hans-Ulrich; Ley-Zaporozhan, Julia; Ley, Sebastian

    2009-08-15

    Magnetic resonance imaging (MRI) of the lung has shown tremendous progress in recent years. This includes parallel imaging, new contrast agents and mechanisms, ultrafast imaging, and respiratory gating. With these improvements in speed and image quality, MRI is now ready for routine clinical use. The main advantage for MRI of the lung is its unique combination of structural and functional assessment within a single imaging examination. This comprehensive imaging assessment is an asset when compared with computed tomography, which is complemented by the fact that MRI does not carry any exposure to ionizing radiation, making it especially advantageous in children, young adults, and for follow-up examinations either in disease surveillance or therapy monitoring. Clinical indications for MRI are: pulmonary vascular disease, especially pulmonary hypertension, airway diseases, especially cystic fibrosis; neoplastic disease, including staging of lung cancer as an alternative imaging modality; all pediatric indications (e.g., congenital anomalies); as well as follow-up examinations. Under investigation is the application of MRI for chronic obstructive pulmonary disease as well as asthma. In this regard the additional benefit from MRI using hyperpolarized gases has to be determined.

  16. Volumetric MR-Guided High-Intensity Focused Ultrasound with Direct Skin Cooling for the Treatment of Symptomatic Uterine Fibroids : Proof-of-Concept Study

    NARCIS (Netherlands)

    Ikink, Marlijne E; van Breugel, Johanna M M; Schubert, Gerald; Nijenhuis, Robbert J; Bartels, LW; Moonen, Chrit T W; van den Bosch, Maurice A A J

    2015-01-01

    Objective. To prospectively assess the safety and technical feasibility of volumetric magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation with direct skin cooling (DISC) during treatment of uterine fibroids. Methods. In this proof-of-concept study, eight patients were

  17. Quality of MR thermometry during palliative MR-guided high-intensity focused ultrasound (MR-HIFU) treatment of bone metastases

    NARCIS (Netherlands)

    Lam, Mie K; Huisman, Merel; Nijenhuis, Robbert J; van den Bosch, Maurice; Viergever, Max A; Moonen, Chrit Tw; Bartels, LW

    2015-01-01

    BACKGROUND: Magnetic resonance (MR)-guided high-intensity focused ultrasound has emerged as a clinical option for palliative treatment of painful bone metastases, with MR thermometry (MRT) used for treatment monitoring. In this study, the general image quality of the MRT was assessed in terms of

  18. Using focus groups in medical education research: AMEE Guide No. 91.

    Science.gov (United States)

    Stalmeijer, Renée E; Mcnaughton, Nancy; Van Mook, Walther N K A

    2014-11-01

    Qualitative research methodology has become an established part of the medical education research field. A very popular data-collection technique used in qualitative research is the "focus group". Focus groups in this Guide are defined as "… group discussions organized to explore a specific set of issues … The group is focused in the sense that it involves some kind of collective activity … crucially, focus groups are distinguished from the broader category of group interview by the explicit use of the group interaction as research data" (Kitzinger 1994, p. 103). This Guide has been designed to provide people who are interested in using focus groups with the information and tools to organize, conduct, analyze and publish sound focus group research within a broader understanding of the background and theoretical grounding of the focus group method. The Guide is organized as follows: Firstly, to describe the evolution of the focus group in the social sciences research domain. Secondly, to describe the paradigmatic fit of focus groups within qualitative research approaches in the field of medical education. After defining, the nature of focus groups and when, and when not, to use them, the Guide takes on a more practical approach, taking the reader through the various steps that need to be taken in conducting effective focus group research. Finally, the Guide finishes with practical hints towards writing up a focus group study for publication.

  19. Controlled Hyperthermia with MRI-guided Focused Ultrasound

    DEFF Research Database (Denmark)

    Hokland, Steffen; Salomir, Rares; Pedersen, Michael

    doses sufficient to induce cellular deactivation thermotherapy is still regarded as an experimental treatment. In contrast to other thermo-therapeutic modalities Focused Ultrasound (FUS) may be employed non-invasively to deliver a highly localized thermal build-up in deep seated regions of the body...

  20. Breast magnetic resonance imaging for the interventionalist: magnetic resonance imaging-guided vacuum-assisted breast biopsy.

    Science.gov (United States)

    Brennan, Sandra B

    2014-03-01

    Magnetic resonance Imaging-guided breast biopsy is an essential component of breast imaging practices offering breast magnetic resonance imaging. Careful planning and preparation allow for an efficient and successful biopsy. Deliberate positioning and controlled compression are keys to a comfortable and cooperative patient. The biopsy is only complete once imaging-histologic correlation has been made by the radiologist. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. New piezocrystal material in the development of a 96-element array transducer for MR-guided focused ultrasound surgery

    Science.gov (United States)

    Qiu, Zhen; Habeshaw, Roderick; Fortine, Julien; Huang, Zhihong; Démoré, Christine; Cochran, Sandy

    2012-11-01

    Piezocrystal materials have been recognized as having better performance than piezoelectric ceramics, and have thus been widely adopted in ultrasound imaging arrays. Although their behaviour is susceptible to temperature and pressure, their large electromechanical coupling coefficients and other excellent piezoelectric properties also offer the potential for further improvements in the efficiency of therapeutic ultrasound transducers. Furthermore, new piezocrystals with modified compositions have been developed recently to increase their tolerance to temperature and pressure. In this work, a prototype of faceted bowl transducer was designed and manufactured as a proof of concept to explore practical issues associated with adoption of piezocrystals for magnetic resonance imaging guided focused ultrasound surgery.

  2. Image-guided focused ultrasound ablation of breast cancer: current status, challenges, and future directions

    NARCIS (Netherlands)

    Schmitz, A.C.; Gianfelice, D.; Daniel, B.L.; Mali, W.P.T.M.; Bosch, M.A.A.J. van den

    2008-01-01

    Image-guided focussed ultrasound (FUS) ablation is a noninvasive procedure that has been used for treatment of benign or malignant breast tumours. Image-guidance during ablation is achieved either by using real-time ultrasound (US) or magnetic resonance imaging (MRI). The past decade phase I

  3. Current and emerging brain applications of MR-guided focused ultrasound.

    Science.gov (United States)

    Meng, Ying; Suppiah, Suganth; Mithani, Karim; Solomon, Benjamin; Schwartz, Michael L; Lipsman, Nir

    2017-01-01

    MRI guided focused ultrasound is an emerging technique that uses acoustic energy to noninvasively treat intracranial disorders. At high frequencies, it can be used to raise tissue temperatures and ablate discrete brain targets with sub-millimeter accuracy. This application is currently under investigation for a broad range of clinical applications, including brain tumors, movement disorders, and psychiatric conditions. At low frequencies MRI guided focused ultrasound can be used to modulate neuronal activity and in conjunction with injected microbubbles, can open the blood-brain barrier to enhance the delivery of therapeutic compounds. The last decade has seen dramatic advances in the science of MRI guided focused ultrasound, helping elucidate both its mechanisms and potential in pre-clinical models, and its translational promise across myriad clinical applications. This review provides an update of current and emerging MRI guided focused ultrasound applications for intracranial disorders and describes future directions and challenges for the field.

  4. MRI-guided focused ultrasound surgery for uterine fibroid treatment: a cost-effectiveness analysis

    National Research Council Canada - National Science Library

    Kong, Chung Y; Meng, Lesley; Omer, Zehra B; Swan, J Shannon; Srouji, Serene; Gazelle, G Scott; Fennessy, Fiona M

    2014-01-01

    OBJECTIVE. The purpose of this article is to evaluate the cost effectiveness of a treatment strategy for symptomatic uterine fibroids that uses MRI-guided focused ultrasound as a first-line therapy relative...

  5. MRT letter: Guided filtering of image focus volume for 3D shape recovery of microscopic objects.

    Science.gov (United States)

    Mahmood, Muhammad Tariq

    2014-12-01

    In this letter, a shape from focus (SFF) method is proposed that utilizes the guided image filtering to enhance the image focus volume efficiently. First, image focus volume is computed using a conventional focus measure. Then each layer of image focus volume is filtered using guided filtering. In this work, the all-in-focus image, which can be obtained from the initial focus volume, is used as guidance image. Finally, improved depth map is obtained from the filtered image focus volume by maximizing the focus measure along the optical axis. The proposed SFF method is efficient and provides better depth maps. The improved performance is highlighted by conducting several experiments using image sequences of simulated and real microscopic objects. The comparative analysis demonstrates the effectiveness of the proposed SFF method. © 2014 Wiley Periodicals, Inc.

  6. Positioning device for MRI-guided high intensity focused ultrasound system

    Energy Technology Data Exchange (ETDEWEB)

    Damianou, Christakis [Frederick Institute of Technology (FIT), Limassol (Cyprus); MEDSONIC, LTD, Limassol (Cyprus); Ioannides, Kleanthis [Polikliniki Igia, Limassol (Cyprus); Milonas, Nicos [Frederick Institute of Technology (FIT), Limassol (Cyprus)

    2008-04-15

    A prototype magnetic resonance imaging (MRI)- compatible positioning device was used to move an MRI-guided high intensity focused ultrasound (HIFU) transducer. The positioning device has three user-controlled degrees of freedom that allow access to various targeted lesions. The positioning device was designed and fabricated using construction materials selected for compatibility with high magnetic fields and fast switching magnetic field gradients encountered inside MRI scanners. The positioning device incorporates only MRI compatible materials such as piezoelectric motors, plastic sheets, brass screws, plastic pulleys and timing belts. The HIFU/MRI system includes the multiple subsystems (a) HIFU system, (b) MR imaging, (c) Positioning device (robot) and associate drivers, (d) temperature measurement, (e) cavitation detection, (f) MRI compatible camera, and (g) Soft ware. The MRI compatibility of the system was successfully demonstrated in a clinical high-field MRI scanner. The ability of the robot to accurately move the transducer thus creating discrete and overlapping lesions in biological tissue was tested successfully. A simple, cost effective, portable positioning device has been developed which can be used in virtually any clinical MRI scanner since it can be sited on the scanner's table. The propagation of HIFU can use either a lateral or superior-inferior approach. Discrete and large lesions were created successfully with reproducible results. (orig.)

  7. Towards magnetic resonance imaging guided radiation therapy (MRIgRT)

    Science.gov (United States)

    Stanescu, Teodor Marius

    The goal of this work is to address key aspects of the magnetic resonance imaging guided radiation therapy (MRIgRT) process of cancer sites. MRIgRT is implemented by using a system comprised of a magnetic resonance imaging (MRI) scanner coupled with a radiation source, in our case a radiotherapy accelerator (Linac). The potential benefits of MRIgRT are the real-time tracking of the tumor and neighbouring healthy anatomy during treatment irradiation leading to on-line treatment plan optimization. Ultimately, this results in an increased accuracy and efficiency of the overall treatment process. A large research effort is conducted at Cross Cancer Institute to develop a hybrid MRI-Linac system consisting of a bi-planar 0.2 T permanent magnet coupled with a 6 MV Linac. The present work is part of this project and aims to address the following key components: (a) magnetic shielding and dosimetric effects of the MRI-Linac system, (b) measure and correction of scanner-related MR image distortions, and (c) MRI-based treatment planning procedure for intracranial lesions. The first two components are essential for the optimal construction and operation of the MRI-Linac system while the third one represents a direct application of the system. The linac passive shielding was achieved by (a) adding two 10 cm thick steel (1020) plates placed at a distance of 10 cm from the structure on opposite sides of the magnet; and (b) a box lined with a 1 mm MuMetal(TM) wall surrounding the Linac. For our proposed MRI-Linac configuration (i.e. 0.2 T field and rotating bi-planar geometry) the maximum dose difference from zero magnetic field case was found to be within 6% and 12% in a water and water-lung-water phantom, respectively. We developed an image system distortion correction method for MRI that relies on adaptive thresholding and an iterative algorithm to determine the 3D distortion field. Applying this technique the residual image distortions were reduced to within the voxel

  8. Feasibility of MRI-guided high intensity focused ultrasound treatment for adenomyosis

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Tien-Ying [State Key Laboratory of Ultrasound Engineering in Medicine, Department of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Zhang, Lian; Chen, Wenzhi [Clinical Center of Tumor Therapy of 2nd Affiliated Hospital of Chongqing Medical University, Chongqing 400010 (China); Liu, Yinjiang; He, Min; Huang, Xiu [State Key Laboratory of Ultrasound Engineering in Medicine, Department of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Orsi, Franco [Interventional Radiology Unit, European Institute of Oncology, 435 Via Ripamonti, 20141 Milan (Italy); Wang, Zhibiao, E-mail: wangzhibiao@haifu.com.cn [State Key Laboratory of Ultrasound Engineering in Medicine, Department of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Clinical Center of Tumor Therapy of 2nd Affiliated Hospital of Chongqing Medical University, Chongqing 400010 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer We tested the feasibility of MRIgHIFU ablation for adenomyosis. Black-Right-Pointing-Pointer Patients were treated with MRIgHIFU under conscious sedation. Black-Right-Pointing-Pointer Patient symptoms were assessed using SSS and UFS-QOL. Black-Right-Pointing-Pointer The mean SSS and UFS-QOL showed significant improvements at follow up. Black-Right-Pointing-Pointer No serious complications were observed 62.5 {+-} 21.6. -- Abstract: Purpose: To test the feasibility of MRI-guided high intensity focused ultrasound ablation for adenomyosis. Materials and methods: Patients with symptomatic adenomyosis were treated with MRI-guided high intensity focused ultrasound (MRIgHIFU). Under conscious sedation, MRIgHIFU was performed by a clinical MRI-compatible focused ultrasound tumour therapeutic system (JM15100, Haifu{sup Registered-Sign} Technology Co. Ltd., Chongqing, China) which is combined with a 1.5 T MRI system (Magnetom Symphony, Siemens Healthcare, Erlangen, Germany). MRI was used to calculate the volume of the uterus and lesion. Non-perfused volume of the targeted lesions was evaluated immediately after MRIgHIFU. Patient symptoms were assessed using symptom severity score (SSS) and uterine fibroids symptoms and quality of life questionnaire (UFS-QOL). Results: Ten patients with mean age of 40.3 {+-} 4 years with an average lesion size of 56.9 {+-} 12.7 mm in diameter were treated. Non-perfused volume and the percentage of non-perfused volume obtained from contrast-enhanced T1 Magnetic resonance images immediately post-treatment were 66.6 {+-} 49.4 cm{sup 3} and 62.5 {+-} 21.6%, respectively. The mean SSS and UFS-QOL showed significant improvements of 25%, 16% and 25% at 3, 6 and 12 months follow up, respectively, to pre-treatment scores. No serious complications were observed. Conclusion: Based on the results from this study, MRIgHIFU treatment appears to be a safe and feasible modality to ablate adenomyosis lesion and

  9. Motor Resonance as a Function of Narrative Time: Further Tests of the Linguistic Focus Hypothesis

    Science.gov (United States)

    Zwaan, Rolf A.; Taylor, Lawrence J.; de Boer, Mirte

    2010-01-01

    Neuroimaging and behavioral studies have revealed involvement of the brain's motor system in language comprehension. The Linguistic-Focus Hypothesis [Taylor, L. J., & Zwaan, R. A. (2008). Motor resonance and linguistic focus. "Quarterly Journal of Experimental Psychology,61", 869-904.] postulates that engagement of the motor system during language…

  10. Axially Modulated Clamped-Guided Arch Resonator for Memory and Logic Applications

    KAUST Repository

    Hafiz, Md Abdullah Al

    2017-11-03

    We experimentally demonstrate memory and logic devices based on an axially modulated clamped-guided arch resonator. The device are electrostatically actuated and capacitively sensed, while the resonance frequency modulation is achieved through an axial electrostatic force from the guided side of the clamped-guided arch microbeam. We present two case studies: first, a dynamic memory based on the nonlinear frequency response of the resonator, and second, a reprogrammable two-input logic gate based on the linear frequency modulation of the resonator. These devices show energy cost per memory/logic operation in pJ, are fully compatible with CMOS fabrication processes, have the potential for on-chip system integration, and operate at room temperature.

  11. Adverse events of extracorporeal ultrasound-guided high intensity focused ultrasound therapy.

    Directory of Open Access Journals (Sweden)

    Tinghe Yu

    Full Text Available BACKGROUND: High-intensity focused ultrasound (HIFU is considered to be an alternative to surgery. Extracorporeal ultrasound-guided HIFU (USgFU has been clinically used to treat solid tumors. Preliminary trials in a small sample of a Western population suggested that this modality was safe. Most trials are performed in China thereby providing comprehensive data for understanding the safety profile. The aim of this study was to evaluate adverse events of USgFU therapy. METHODS AND FINDINGS: Clinical data were searched in 2 Chinese databases. Adverse events of USgFU were summarized and compared with those of magnetic resonance-guided HIFU (MRgFU; for uterine, bone or breast tumor and transrectal ultrasound-guided HIFU (for prostate cancer or benign prostate hyperplasia. USgFU treatment was performed using 7 types of device. Side effects were evaluated in 13262 cases. There were fewer adverse events in benign lesions than in malignant lesions (11.81% vs. 21.65%, p<0.0001. Rates of adverse events greatly varied between the disease types (0-280%, p<0.0001 and between the applied HIFU devices in both malignant (10.58-44.38%, p<0.0001 and benign lesions (1.67-17.57%, p<0.0001. Chronological analysis did not demonstrate a decrease in the rate of adverse events. Based upon evaluable adverse events, incidences in USgFU were consistent with those in MRgFU or transrectal HIFU. Some side effects frequently occurred following transrectal HIFU were not reported in USgFU. Several events including intrahepatic metastasis, intraoperative high fever, and occlusions of the superior mesenteric artery should be of particular concern because they have not been previously noted. The types of adverse events suggested that they were ultrasonic lesions. CONCLUSION: The frequency of adverse events depended on the location of the lesion and the type of HIFU device; however, side effects of USgFU were not yet understood. USgFU did not decrease the incidence of adverse events

  12. Focus on advanced magnetic resonance techniques in clinical practice: magnetic resonance neurography.

    Science.gov (United States)

    Carpenter, Elizabeth L; Bencardino, Jenny T

    2015-05-01

    Magnetic resonance neurography (MRN) provides the greatest degree of soft tissue contrast in the evaluation of peripheral nerves. Utilization of MRN relies on (1) peripheral nerve anatomy, (2) the spectrum of pathology, and (3) familiarity with dedicated MR imaging techniques. Although there remain several pitfalls in MRN imaging, awareness of these pitfalls improves imaging quality and limits misinterpretation. Most importantly, maintaining a direct line of communication with the referring clinician allows for the greatest degree of diagnostic accuracy. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Methods for abdominal tumor ablation through image-guided focused ultrasound

    NARCIS (Netherlands)

    Ramaekers, P.|info:eu-repo/dai/nl/413970531

    2017-01-01

    The work described in this thesis was aimed at developing and improving methods for extracorporeal image-guided focused ultrasound ablation of abdominal tumors. Main challenges that hamper the widespread clinical adoption of focused ultrasound therapy for the treatment of abdominal cancers include

  14. Magnetic Resonance - Transrectal Ultrasound Fusion Guided Prostate Biopsy

    National Research Council Canada - National Science Library

    Ömer Burak Argun; Can Öbek; Ali Riza Kural

    2016-01-01

    .... Today, MRI-transrectal ultrasound (TRUS) fusion guided biopsy methods are being used increasingly, especially for patients with an increasing prostate specific antigen level after a previous negative biopsy result and for patients under...

  15. Imaging findings in MR imaging-guided focused ultrasound treatment for patients with essential tremor.

    Science.gov (United States)

    Wintermark, M; Druzgal, J; Huss, D S; Khaled, M A; Monteith, S; Raghavan, P; Huerta, T; Schweickert, L C; Burkholder, B; Loomba, J J; Zadicario, E; Qiao, Y; Shah, B; Snell, J; Eames, M; Frysinger, R; Kassell, N; Elias, W J

    2014-05-01

    MR imaging-guided focused sonography surgery is a new stereotactic technique that uses high-intensity focused sonography to heat and ablate tissue. The goal of this study was to describe MR imaging findings pre- and post-ventralis intermedius nucleus lesioning by MR imaging-guided focused sonography as a treatment for essential tremor and to determine whether there was an association between these imaging features and the clinical response to MR imaging-guided focused sonography. Fifteen patients with medication-refractory essential tremor prospectively gave consent; were enrolled in a single-site, FDA-approved pilot clinical trial; and were treated with transcranial MR imaging-guided focused sonography. MR imaging studies were obtained on a 3T scanner before the procedure and 24 hours, 1 week, 1 month, and 3 months following the procedure. On T2-weighted imaging, 3 time-dependent concentric zones were seen at the site of the focal spot. The inner 2 zones showed reduced ADC values at 24 hours in all patients except one. Diffusion had pseudonormalized by 1 month in all patients, when the cavity collapsed. Very mild postcontrast enhancement was seen at 24 hours and again at 1 month after MR imaging-guided focused sonography. The total lesion size and clinical response evolved inversely compared with each other (coefficient of correlation = 0.29, P value = .02). MR imaging-guided focused sonography can accurately ablate a precisely delineated target, with typical imaging findings seen in the days, weeks, and months following the treatment. Tremor control was optimal early when the lesion size and perilesional edema were maximal and was less later when the perilesional edema had resolved. © 2014 by American Journal of Neuroradiology.

  16. Design of guided-mode resonance mirrors for short laser cavities.

    Science.gov (United States)

    Kondo, Tomohiro; Ura, Shogo; Magnusson, Robert

    2015-08-01

    A guided-mode resonance mirror (GMRM) consists of a waveguide grating integrated on an optical buffer layer on a high-reflection substrate. An incident free-space wave at the resonance wavelength is once coupled by the grating to a guided mode and coupled again by the same grating back to free space. The reflection characteristics of a GMRM are numerically calculated and theoretically analyzed. It is predicted that notch filtering or flat reflection spectra are obtained depending on the optical buffer layer thickness. Design of short cavities using a GMRM is discussed for potential application in surface-mount packaging of diode lasers onto a photonic circuit board.

  17. Where Do Transrectal Ultrasound- and Magnetic Resonance Imaging-guided Biopsies Miss Significant Prostate Cancer?

    DEFF Research Database (Denmark)

    Boesen, Lars; Nørgaard, Nis; Løgager, Vibeke

    2017-01-01

    OBJECTIVE: To identify the location of missed significant prostate cancer (sPCa) lesions by transrectal ultrasound-guided biopsy (TRUSbx) and multiparametric magnetic resonance imaging-guided biopsy (mpMRIbx) in men undergoing repeat biopsies. MATERIALS AND METHODS: A total of 289 men with prior...... negative TRUSbx underwent multiparametric magnetic resonance imaging. The location of any suspicious lesion was registered and scored using Prostate Imaging Reporting and Data System version 1 classification according to the likelihood of being sPCa. All patients underwent repeat transrectal ultrasound...

  18. Ultrasound-guided high-intensity focused ultrasound ablation for treating uterine arteriovenous malformation.

    Science.gov (United States)

    Yan, X; Zhao, C; Tian, C; Wen, S; He, X; Zhou, Y

    2017-08-01

    To explore HIFU treatment for uterine arteriovenous malformation. A case report. Gynaecological department in a university teaching hospital of China. A patient with uterine arteriovenous malformation. The diagnosis of uterine arteriovenous malformation was made through MRI. Ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation was performed. HIFU is effective in treating uterine arteriovenous malformation. The patient had reduction of the lesion volume and obvious symptom relief, without significant adverse effects. HIFU can be used as a new treatment option for uterine arteriovenous malformation. Ultrasound-guided high-intensity focused ultrasound ablation is effective in treating uterine arteriovenous malformation. © 2017 Royal College of Obstetricians and Gynaecologists.

  19. MRI-guided focused ultrasound surgery for uterine fibroid treatment: a cost-effectiveness analysis.

    Science.gov (United States)

    Kong, Chung Y; Meng, Lesley; Omer, Zehra B; Swan, J Shannon; Srouji, Serene; Gazelle, G Scott; Fennessy, Fiona M

    2014-08-01

    OBJECTIVE. The purpose of this article is to evaluate the cost effectiveness of a treatment strategy for symptomatic uterine fibroids that uses MRI-guided focused ultrasound as a first-line therapy relative to uterine artery embolization (UAE) or hysterectomy. MATERIALS AND METHODS. We developed a decision-analytic model to compare the cost effectiveness of three first-line treatment strategies: MRI-guided focused ultrasound, UAE, and hysterectomy. Treatment-specific short- and long-term utilities, lifetime costs, and quality-adjusted life years (QALYs) were incorporated, allowing us to conduct an incremental cost-effectiveness analysis, using a societal willingness-to-pay (WTP) threshold of $50,000/QALY to designate a strategy as cost effective. Sensitivity analyses were subsequently performed on all key parameters. RESULTS. In the base-case analysis, UAE as a first-line treatment of symptomatic fibroids was the most effective and expensive strategy (22.75 QALYs; $22,968), followed by MRI-guided focused ultrasound (22.73 QALYs; $20,252) and hysterectomy (22.54 QALYs; $11,253). MRI-guided focused ultrasound was cost effective relative to hysterectomy, with an associated incremental cost-effectiveness ratio (ICER) of $47,891/QALY. The ICER of UAE relative to MRI-guided focused ultrasound was $234,565/QALY, exceeding the WTP threshold of $50,000/QALY, therefore rendering MRI-guided focused ultrasound also cost effective relative to UAE. In sensitivity analyses, results were robust to changes in most parameters but were sensitive to changes in probabilities of recurrence, symptom relief, and quality-of-life measures. CONCLUSION. First-line treatment of eligible women with MRI-guided focused ultra-sound is a cost-effective noninvasive strategy. For those not eligible for MRI-guided focused ultra-sound, UAE remains a cost-effective option. These recommendations integrate both the short- and long-term decrements in quality of life associated with the specific treatment

  20. Magnetic resonance imaging-guided prostate biopsy: Present and future

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chan Kyo [Dept. of Radiology, and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2015-02-15

    Systemic transrectal ultrasound-guided biopsy (TRUSBx) is the standard procedure for diagnosing prostate cancer (PCa), but reveals a limited accuracy for the detection of cancer. Currently, multiparametric MR imaging (mp-MRI) is increasingly regarded as a promising method to detect PCa with an excellent positive predictive value. The use of mp-MRI during a MRI-guided biopsy (MRGB) procedure improves the quality of a targeted biopsy. The aim of this article is to provide an overview about the MRGB technique for PCa detection, to review the accuracy and clinical indications of MRGB and discuss its current issues and further directions. A MRGB seems accurate and efficient for the detection of clinically significant PCa in men with previous negative TRUSBx. Moreover, it may decrease the detection of clinically insignificant cancers with fewer biopsy cores.

  1. Safety of ultrasound-guided high-intensity focused ultrasound ablation for diffuse adenomyosis: A retrospective cohort study.

    Science.gov (United States)

    Feng, Yujie; Hu, Liang; Chen, Wenzhi; Zhang, Rong; Wang, Xi; Chen, Jinyun

    2017-05-01

    To evaluate the safety of ultrasound-guided high-intensity focused ultrasound (HIFU) ablation for patients with diffuse adenomyosis. This was a retrospective cohort study. The data was collected from 417 symptomatic adenomyosis patients who underwent ultrasound-guided HIFU between January 2012 and December 2015 at 1st Affiliated Hospital of Chongqing Medical University, Chongqing, China. Among them were 260 patients with diffuse adenomyosis (Group D) and 157 patients with focal adenomyosis (Group F). All patients underwent contrast-enhanced magnetic resonance imaging (MRI) one week before and the day after HIFU treatment. Successful treatment with HIFU was measured by the non-perfused volume ratio (NPVR). Intraprocedural and postprocedural adverse effects and complications were recorded to assess the safety of the procedure. Patients were followed-up for three months post-treatment. Complications were given a grade A through F according to the SIR Standards. All patients successfully completed the procedure, non-perfused regions appeared in 415 (99.5%) patients. The non-perfused volume ratio (NPVR) of Group D was significantly lower than that of Group F (P0.05) and neither of the reported complications of SIR-C-SIR-F occurred within the two groups. Based on our results, ultrasound-guided HIFU is safe for the treatment of diffuse adenomyosis, and controlling the ablation zone is crucial to ensure patients' safety. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. MR guided focused ultrasound: technical acceptance measures for a clinical system

    Energy Technology Data Exchange (ETDEWEB)

    Gorny, K R; Hangiandreou, N J; Hesley, G K; Gostout, B S; McGee, K P; Felmlee, J P [Department of Radiology, Mayo Clinic, Rochester, MN 55905 (United States)

    2006-06-21

    Magnetic resonance (MR) guided focused ultrasound (MRgFUS) is a hybrid technique which offers efficient and safe focused ultrasound (FUS) treatments of uterine fibroids under MR guidance and monitoring. As a therapy device, MRgFUS requires systematic testing over a wide range of operational parameters prior to use in the clinical environment. We present technical acceptance tests and data for the first clinical MRgFUS system, ExAblate (registered) 2000 (InSightec Inc., Haifa, Israel), that has been FDA approved for treating uterine fibroids. These tests characterize MRgFUS by employing MR temperature measurements in tissue mimicking phantoms. The coronal scan plane is empirically demonstrated to be most reliable for measuring temperature elevations resulting from high intensity ultrasound (US) pulses ('sonications') and shows high sensitivity to changes in sonication parameters. Temperatures measured in the coronal plane were used as a measure of US energy deposited within the focal spot for a range of sonication parameters used in clinical treatments: spot type, spot length, output power, sonication duration, US frequency, and depth of sonication. In addition, MR images acquired during sonications were used to measure effective diameters and lengths of available sonication spot types and lengths. At a constant 60 W output power, the effective spot type diameters were measured to vary between 4.7 {+-} 0.3 mm and 6.6 {+-} 0.4 mm; treatment temperatures were found to decrease with increasing spot diameter. Prescribing different spot lengths was found to have no effect on the measured length or on measured temperatures. Tests of MRgFUS positioning accuracy determined errors in the direction parallel to the propagation of the US beam to be significantly greater than those in the perpendicular direction; most sonication spots were erroneously positioned towards the FUS transducer. The tests reported here have been demonstrated to be sufficiently sensitive to

  3. T2-based temperature monitoring in bone marrow for MR-guided focused ultrasound

    OpenAIRE

    Ozhinsky, Eugene; Han, Misung; Bucknor, Matthew; Krug, Roland; Rieke, Viola

    2016-01-01

    Background Current clinical protocols for MR-guided focused ultrasound (MRgFUS) treatment of osseous lesions, including painful bone metastases and osteoid osteomas, rely on measurement of the temperature change in adjacent muscle to estimate the temperature of the bone. The goal of this study was to determine if T2-based thermometry could be used to monitor the temperature change in bone marrow during focused ultrasound ablation of bone lesions. Methods We investigated the dependence of T2 o...

  4. MRI-Guided Focused Ultrasound in Parkinson’s Disease: A Review

    Directory of Open Access Journals (Sweden)

    Ilana Schlesinger

    2017-01-01

    Full Text Available MRI-guided focused ultrasound is a new technology that enables intracranial ablation. Since lesioning ameliorates some of the symptoms of PD, this technology is being explored as a possible treatment for medication resistant symptoms in PD patients. The purpose of this paper is to review the clinical use and treatment outcomes of PD patients treated to date with this technology.

  5. In Situ Tuning of Focused-Ion-Beam Defined Nanomechanical Resonators Using Joule Heating

    DEFF Research Database (Denmark)

    Homann, Lasse Vinther; Booth, Tim; Lei, Anders

    2011-01-01

    Nanomechanical resonators have a huge potential for a variety of applications, including high-resolution mass sensing. In this paper, we demonstrate a novel rapid prototyping method for fabricating nanoelectromechanical systems using focused-ion-beam milling as well as in situ electromechanical...... characterization using a transmission electron microscope. Nanomechanical resonators were cut out of thin membrane chips, which have been prefabricated using standard cleanroom processing. We have demonstrated the fabrication of double-clamped beams with feature sizes down to 200 nm using a fabrication time of 30...... min per device. Afterwards, the dynamic and structural properties of a double-clamped beam were measured after subsequent Joule heating events in order to ascertain the dependence of the internal structure on the Q-factor and resonant frequency of the device. It was observed that a change from...

  6. MR-Guided High-Intensity Focused Ultrasound Ablation of Breast Cancer with a Dedicated Breast Platform

    Energy Technology Data Exchange (ETDEWEB)

    Merckel, Laura G., E-mail: L.G.Merckel-2@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands); Bartels, Lambertus W., E-mail: W.Bartels@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Koehler, Max O., E-mail: max.kohler@philips.com [Philips Healthcare (Finland); Bongard, H. J. G. Desiree van den, E-mail: D.vandenBongard@umcutrecht.nl [University Medical Center Utrecht, Department of Radiotherapy (Netherlands); Deckers, Roel, E-mail: R.Deckers-2@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Mali, Willem P. Th. M., E-mail: W.Mali@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands); Binkert, Christoph A., E-mail: Christoph.Binkert@ksw.ch [Cantonal Hospital Winterthur, Department of Radiology (Switzerland); Moonen, Chrit T., E-mail: C.Moonen@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Gilhuijs, Kenneth G. A., E-mail: K.G.A.Gilhuijs@umcutrecht.nl; Bosch, Maurice A. A. J. van den, E-mail: mbosch@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands)

    2013-04-15

    Optimizing the treatment of breast cancer remains a major topic of interest. In current clinical practice, breast-conserving therapy is the standard of care for patients with localized breast cancer. Technological developments have fueled interest in less invasive breast cancer treatment. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a completely noninvasive ablation technique. Focused beams of ultrasound are used for ablation of the target lesion without disrupting the skin and subcutaneous tissues in the beam path. MRI is an excellent imaging method for tumor targeting, treatment monitoring, and evaluation of treatment results. The combination of HIFU and MR imaging offers an opportunity for image-guided ablation of breast cancer. Previous studies of MR-HIFU in breast cancer patients reported a limited efficacy, which hampered the clinical translation of this technique. These prior studies were performed without an MR-HIFU system specifically developed for breast cancer treatment. In this article, a novel and dedicated MR-HIFU breast platform is presented. This system has been designed for safe and effective MR-HIFU ablation of breast cancer. Furthermore, both clinical and technical challenges are discussed, which have to be solved before MR-HIFU ablation of breast cancer can be implemented in routine clinical practice.

  7. Plasmonic metalens based on coupled resonators for focusing of surface plasmons

    KAUST Repository

    Xu, Quan

    2016-11-29

    As an essential functionality, flexible focusing of surface plasmons (SPs) is of particular interest in nonlinear optics and highly integrated plasmonic circuitry. Here, we developed a versatile plasmonic metalens, a metasurface comprised of coupled subwavelength resonators, whose optical responses exhibit a remarkable feature of electromagnetically induced transparency (EIT). We demonstrate numerically and experimentally how a proper spatial design of the unit elements steers SPs to arbitrary foci based on the holographic principles. More specifically, we show how to control the interaction between the constituent EIT resonators to efficiently manipulate the focusing intensity of SPs. We also demonstrated that the proposed metalens is capable of achieving frequency division multiplexing. The power and simplicity of the proposed design would offer promising opportunities for practical plasmonic devices.

  8. Cost-effectiveness of magnetic resonance (MR) imaging and MR-guided targeted biopsy versus systematic transrectal ultrasound-guided biopsy in diagnosing prostate cancer: a modelling study from a health care perspective

    NARCIS (Netherlands)

    Rooij, M. de; Crienen, S.; Witjes, J.A.; Barentsz, J.O.; Rovers, M.M.; Grutters, J.P.C.

    2014-01-01

    BACKGROUND: The current diagnostic strategy using transrectal ultrasound-guided biopsy (TRUSGB) raises concerns regarding overdiagnosis and overtreatment of prostate cancer (PCa). Interest in integrating multiparametric magnetic resonance imaging (MRI) and magnetic resonance-guided biopsy (MRGB)

  9. Workflow and intervention times of MR-guided focused ultrasound - Predicting the impact of new techniques.

    Science.gov (United States)

    Loeve, Arjo J; Al-Issawi, Jumana; Fernandez-Gutiérrez, Fabiola; Langø, Thomas; Strehlow, Jan; Haase, Sabrina; Matzko, Matthias; Napoli, Alessandro; Melzer, Andreas; Dankelman, Jenny

    2016-04-01

    Magnetic resonance guided focused ultrasound surgery (MRgFUS) has become an attractive, non-invasive treatment for benign and malignant tumours, and offers specific benefits for poorly accessible locations in the liver. However, the presence of the ribcage and the occurrence of liver motion due to respiration limit the applicability MRgFUS. Several techniques are being developed to address these issues or to decrease treatment times in other ways. However, the potential benefit of such improvements has not been quantified. In this research, the detailed workflow of current MRgFUS procedures was determined qualitatively and quantitatively by using observation studies on uterine MRgFUS interventions, and the bottlenecks in MRgFUS were identified. A validated simulation model based on discrete events simulation was developed to quantitatively predict the effect of new technological developments on the intervention duration of MRgFUS on the liver. During the observation studies, the duration and occurrence frequencies of all actions and decisions in the MRgFUS workflow were registered, as were the occurrence frequencies of motion detections and intervention halts. The observation results show that current MRgFUS uterine interventions take on average 213min. Organ motion was detected on average 2.9 times per intervention, of which on average 1.0 actually caused a need for rework. Nevertheless, these motion occurrences and the actions required to continue after their detection consumed on average 11% and up to 29% of the total intervention duration. The simulation results suggest that, depending on the motion occurrence frequency, the addition of new technology to automate currently manual MRgFUS tasks and motion compensation could potentially reduce the intervention durations by 98.4% (from 256h 5min to 4h 4min) in the case of 90% motion occurrence, and with 24% (from 5h 19min to 4h 2min) in the case of no motion. In conclusion, new tools were developed to predict how

  10. Selecting detection wavelength of resonant cavity-enhanced photodetectors by guided-mode resonance reflectors.

    Science.gov (United States)

    Lai, Kuo-Wei; Lee, Yi-Shan; Fu, Ying-Jhe; Lin, Sheng-Di

    2012-02-13

    We propose and demonstrate a novel device structure of resonant cavity-enhanced photodetector (RCE-PD). The new RCE-PD structure consists of a bottom distributed Bragg reflector (DBR), a cavity with InGaAs multiple quantum wells (MQWs) for light absorption and a top mirror of sub-wavelength grating. By changing the fill factor of the 2-D grating, the effective cavity length of RCE-PDs can be varied so the resonant wavelength can be selected post growth. Accordingly, we can fabricate an array of PDs on a single chip, on which every PD aims for a specific wavelength.

  11. Development of novel adjustable focus head mount display for concurrent image-guided treatment applications.

    Science.gov (United States)

    Choi, Hojong; Ryu, Jaemyung; Yoon, Changhan

    2017-12-01

    A conventional see-through head mount display contains many optical lenses, which can be problematic in image-guided treatment applications due to its size, weight, structure, and focus limitation. Therefore, we have designed a new type of see-through head mount display with a reduced number of optical lenses and an adequate optical resolution that can be utilized for image-guided treatment applications. A new type of adjustable focus head mount display with expanded virtual images and an external treatment space that can be provided to the eyes of a user by enlarging the images of a small display is designed and investigated in this study. This type of head mount display can be used in image-guided treatment applications because of the dual paths of imaging and treatment from the optical systems. Therefore, this system with an adjustable focus function can aid doctors in obtaining images for the treatment of the eyes of patients because every patient has a unique pupil size. The results of the adjustable focus see-through head mount display showed distortion values of +0.36% in the +1 diopter location and -0.55% in the -4 diopter location, and there are less significant modulation transfer function differences within the ±5 diopter locations. Low optical distortions within ±0.5 diopters can help doctors image the eye conditions of patients through fewer image processing techniques. Therefore, the designed adjustable focus head mount display can provide low optical aberrations and high optical modulation transfer function resolutions for image-guided treatment applications.

  12. Safety and Efficacy of Magnetic Resonance-Guided Vacuum-Assisted Large-Volume Breast Biopsy (MR-Guided VALB).

    Science.gov (United States)

    Schrading, Simone; Strobel, Kevin; Keulers, Annika; Dirrichs, Timm; Kuhl, Christiane K

    2017-03-01

    Magnetic resonance (MR)-guided vacuum-biopsy is technically demanding and may fail depending on target-lesion size or breast size, and location of lesions within the breast. We developed an MR-guided vacuum-assisted biopsy protocol that collects larger amounts of tissue, aiming at an at least partial or complete ablation of the target-lesion, just as it is intended during surgical (excisional) biopsy. Rationale is to avoid biopsy failures (false-negative results due to undersampling) by collecting larger amounts of tissue. We report on our experience with MR-guided vacuum-assisted large-volume breast biopsy (VALB) (MR-guided VALB) with regard to clinical success and complication rates. Institutional review board-approved analysis of 865 patients with 1414 MR imaging (MRI)-only breast lesions who underwent tissue sampling under MRI guidance. Magnetic resonance-guided VALB was performed on a 1.5 T-system with a 9G system. Per target lesion, we collected at least 24 samples, with the biopsy notch directed toward the position of the target until on postbiopsy control imaging the target lesion appeared completely or at least greatly removed. The standard-of-reference was established by at least 24-months follow-up (for benign biopsy results), or results of surgical histology (for malignant or borderline results). We investigated the technical success rates as a function of factors that usually interfere with MR-guided vacuum biopsy. Target lesions were located in the central versus peripheral parts of the breast in 66.6% (941/1414) versus 33.6% (473/1414), occurred in large, intermediate, or small breasts in 22.7% (321/1414), 56.4% (797/1414), or 20.9% (296/1414), corresponded to nonmass enhancement (NME) versus mass enhancement (ME) in 64.0% (905/1414) vs. 36.0% (509/1414), with an average size of 23 mm for NME versus 9 mm for ME, respectively. Primary technical failures, that is, inability to reach the target lesion occurred in 0.2% of patients (2/865) and 0.1% of

  13. MRI-guided focused ultrasound surgery in musculoskeletal diseases: the hot topics

    Science.gov (United States)

    Napoli, Alessandro; Sacconi, Beatrice; Battista, Giuseppe; Guglielmi, Giuseppe; Catalano, Carlo; Albisinni, Ugo

    2016-01-01

    MRI-guided focused ultrasound surgery (MRgFUS) is a minimally invasive treatment guided by the most sophisticated imaging tool available in today's clinical practice. Both the imaging and therapeutic sides of the equipment are based on non-ionizing energy. This technique is a very promising option as potential treatment for several pathologies, including musculoskeletal (MSK) disorders. Apart from clinical applications, MRgFUS technology is the result of long, heavy and cumulative efforts exploring the effects of ultrasound on biological tissues and function, the generation of focused ultrasound and treatment monitoring by MRI. The aim of this article is to give an updated overview on a “new” interventional technique and on its applications for MSK and allied sciences. PMID:26607640

  14. Guided-mode resonant filters and reflectors: Principles, design, and fabrication

    Science.gov (United States)

    Niraula, Manoj

    angular and spectral domains and realized with carefully crafted nanogratings operating in the non-subwavelength regime. We study the pathway and inter-modal interference effects inducing this intriguing reflection state. In a proof-of-concept experiment, we obtain angular and spectral bandwidths of 4 mrad and 1 nm, respectively. This filter concept can be used for focus-free spectral and spatial filtering in compact holographic and interferometric optical instruments. We report unpolarized broadband reflectors enabled by a serial arrangement of a pair of polarized subwavelength gratings. Optimized with inverse numerical methods, our elemental gratings consist of a partially etched crystalline-silicon film on a quartz substrate. The resulting reflectors exhibit extremely wide spectral reflection bands in one polarization. By arranging two such reflectors sequentially with orthogonal periodicities, there results an unpolarized spectral band possessing bandwidth exceeding those of the individual polarized bands. In the experiments reported herein, we achieve zero-order reflectance exceeding 97% under unpolarized light incidence over a 500-nm-wide wavelength band in the near-infrared domain. Moreover, the resonant unpolarized broadband accommodates an ultra-high-reflection band spanning 85 nm and exceeding 99.9% in efficiency. The elemental polarization-sensitive reflectors based on one-dimensional resonant gratings have simple design, robust performance, and are straightforward to fabricate. Hence, this technology is a promising alternative to traditional multilayer thin-film reflectors especially at longer wavelengths of light where multilayer deposition may be infeasible or impractical. We demonstrate an interesting attribute of resonant bandpass filters which is high angular stability for fully conical light incidence. Fashioning an experimental bandpass filter with a subwavelength silicon grating on a quartz substrate, we show that fully conical incidence provides an

  15. Image-guided focused ultrasound ablation of breast cancer: current status, challenges, and future directions

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, A.C.; Mali, W.P.T.M. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Gianfelice, D. [University Health Network C/O Toronto General Hospital, Department of Radiology, Toronto (Canada); Daniel, B.L. [Stanford University, Department of Radiology, Stanford, CA (United States); Bosch, M.A.A.J. van den [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Stanford University, Department of Radiology, Stanford, CA (United States); Lucas MR Imaging Center, Department of Radiology, Stanford, CA (United States)

    2008-07-15

    Image-guided focussed ultrasound (FUS) ablation is a non-invasive procedure that has been used for treatment of benign or malignant breast tumours. Image-guidance during ablation is achieved either by using real-time ultrasound (US) or magnetic resonance imaging (MRI). The past decade phase I studies have proven MRI-guided and US-guided FUS ablation of breast cancer to be technically feasible and safe. We provide an overview of studies assessing the efficacy of FUS for breast tumour ablation as measured by percentages of complete tumour necrosis. Successful ablation ranged from 20% to 100%, depending on FUS system type, imaging technique, ablation protocol, and patient selection. Specific issues related to FUS ablation of breast cancer, such as increased treatment time for larger tumours, size of ablation margins, methods used for margin assessment and residual tumour detection after FUS ablation, and impact of FUS ablation on sentinel node procedure are presented. Finally, potential future applications of FUS for breast cancer treatment such as FUS-induced anti-tumour immune response, FUS-mediated gene transfer, and enhanced drug delivery are discussed. Currently, breast-conserving surgery remains the gold standard for breast cancer treatment. (orig.)

  16. TU-B-210-00: MR-Guided Focused Ultrasound Therapy in Oncology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    MR guided focused ultrasound (MRgFUS), or alternatively high-intensity focused ultrasound (MRgHIFU), is approved for thermal ablative treatment of uterine fibroids and pain palliation in bone metastases. Ablation of malignant tumors is under active investigation in sites such as breast, prostate, brain, liver, kidney, pancreas, and soft tissue. Hyperthermia therapy with MRgFUS is also feasible, and may be used in conjunction with radiotherapy and for local targeted drug delivery. MRI allows in situ target definition and provides continuous temperature monitoring and subsequent thermal dose mapping during HIFU. Although MRgHIFU can be very precise, treatment of mobile organs is challenging and advanced techniques are required because of artifacts in MR temperature mapping, the need for intercostal firing, and need for gated HIFU or tracking of the lesion in real time. The first invited talk, “MR guided Focused Ultrasound Treatment of Tumors in Bone and Soft Tissue”, will summarize the treatment protocol and review results from treatment of bone tumors. In addition, efforts to extend this technology to treat both benign and malignant soft tissue tumors of the extremities will be presented. The second invited talk, “MRI guided High Intensity Focused Ultrasound – Advanced Approaches for Ablation and Hyperthermia”, will provide an overview of techniques that are in or near clinical trials for thermal ablation and hyperthermia, with an emphasis of applications in abdominal organs and breast, including methods for MRTI and tracking targets in moving organs. Learning Objectives: Learn background on devices and techniques for MR guided HIFU for cancer therapy Understand issues and current status of clinical MRg HIFU Understand strategies for compensating for organ movement during MRgHIFU Understand strategies for strategies for delivering hyperthermia with MRgHIFU CM - research collaboration with Philips.

  17. Thermal ablation of uterine fibroids using MR-guided focused ultrasound-a truly non-invasive treatment modality

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, Alexander [The Royal Marsden Hospital: Institute of Cancer Research, Joint Department of Physics, Surrey (United Kingdom); The Royal Marsden Hospital: Institute of Cancer Research, Department of Urology, Surrey (United Kingdom); Haar, Gail ter [The Royal Marsden Hospital: Institute of Cancer Research, Joint Department of Physics, Surrey (United Kingdom)

    2007-10-15

    Uterine fibroids are a significant source of morbidity for women of reproductive age. Definitive treatment has traditionally been a hysterectomy, but increasingly women are not prepared to undergo such an invasive procedure for a benign and usually self-limiting condition. Although a number of minimally invasive techniques are now available, focused ultrasound has a considerable advantage over them as it is completely non-invasive and does not require an anaesthetic. Improvements in imaging techniques, particularly magnetic resonance imaging (MRI), have enabled the accurate planning, targeting and monitoring of treatments. We review the early experience of focused ultrasound surgery for the treatment of fibroids, and, in particular, the results of the recent phase I, II and III multi-centre clinical trials. These trials and other studies which demonstrate that MR-guided focused ultrasound ablation is feasible, safe and appears to have an efficacy that is comparable with other treatment modalities are described. This technique has the advantages of being non-invasive and being deliverable as an out-patient procedure. (orig.)

  18. A historical overview of magnetic resonance imaging, focusing on technological innovations.

    Science.gov (United States)

    Ai, Tao; Morelli, John N; Hu, Xuemei; Hao, Dapeng; Goerner, Frank L; Ager, Bryan; Runge, Val M

    2012-12-01

    Magnetic resonance imaging (MRI) has now been used clinically for more than 30 years. Today, MRI serves as the primary diagnostic modality for many clinical problems. In this article, historical developments in the field of MRI will be discussed with a focus on technological innovations. Topics include the initial discoveries in nuclear magnetic resonance that allowed for the advent of MRI as well as the development of whole-body, high field strength, and open MRI systems. Dedicated imaging coils, basic pulse sequences, contrast-enhanced, and functional imaging techniques will also be discussed in a historical context. This article describes important technological innovations in the field of MRI, together with their clinical applicability today, providing critical insights into future developments.

  19. Magnetic resonance spectroscopy-guided transperineal prostate biopsy and brachytherapy for recurrent prostate cancer.

    Science.gov (United States)

    Barnes, Agnieszka Szot; Haker, Steven J; Mulkern, Robert V; So, Minna; D'Amico, Anthony V; Tempany, Clare M

    2005-12-01

    Brachytherapy targeted to the peripheral zone with magnetic resonance imaging (MRI) guidance is a prostate cancer treatment option with potentially fewer complications than other treatments. Follow-up MRI when failure is suspected is, however, difficult because of radiation-induced changes. Furthermore, MR spectroscopy (MRS) is compromised by susceptibility artifacts from radioactive seeds in the peripheral zone. We report a case in which combined MRI/MRS was useful for the detection of prostate cancer in the transitional zone in patients previously treated with MR-guided brachytherapy. We propose that MRI/MRS can help detect recurrent prostate cancer, guide prostate biopsy, and help manage salvage treatment decisions.

  20. Review of Synthetically Focused Guided Wave Imaging Techniques With Application to Defect Sizing

    Science.gov (United States)

    Davies, J.; Simonetti, F.; Lowe, M.; Cawley, P.

    2006-03-01

    Synthetically focused imaging has been used for some time in the NDE community. The techniques have primarily been directed towards imaging using bulk waves. There has recently been use of SAFT (Synthetic Aperture Focusing Technique) using guided waves in plates. Here, we review three different synthetically focused imaging algorithms for a linear array aperture: CSM (Common Source Method), SAFT and TFM (Total Focusing Method). The resolution of the different techniques is obtained from scalar diffraction theory and then validated by means of a low frequency (50kHz) steel plate experiment using PZT excitation and laser reception of the A0 mode. Imaging of through thickness slits parallel to the array is then discussed.

  1. Design and use of guided mode resonance filters for refractive index sensing

    DEFF Research Database (Denmark)

    Hermannsson, Pétur Gordon

    This Ph.D. thesis is concerned with the design and use of guided mode resonance filters (GMRF) for applications in refractive index sensing. GMRFs are optical nanostructures capable of efficiently and resonantly reflecting a narrow wavelength interval of incident broad band light. They combine...... to changes in refractive index that occur within the region overlapped by the quasi guided mode, and GMRFs are thus well suited for optical sensing and tunable filter applications. They produce a polarization dependent response and can be optically characterized in both reflection and transmission....... The structures investigated in this thesis were fabricated in a process based on nanoreplication, in which the surface of a polymer was patterned with a structured master, cured with ultra-violet light and coated with a high refractive index material. The masters were defined using electron beam lithography...

  2. Optimally designed narrowband guided-mode resonance reflectance filters for mid-infrared spectroscopy

    OpenAIRE

    Liu, Jui-Nung; Schulmerich, Matthew V.; Bhargava, Rohit; Cunningham, Brian T.

    2011-01-01

    An alternative to the well-established Fourier transform infrared (FT-IR) spectrometry, termed discrete frequency infrared (DFIR) spectrometry, has recently been proposed. This approach uses narrowband mid-infrared reflectance filters based on guided-mode resonance (GMR) in waveguide gratings, but filters designed and fabricated have not attained the spectral selectivity (≤ 32 cm−1) commonly employed for measurements of condensed matter using FT-IR spectroscopy. With the incorporation of disp...

  3. Feasibility of MRI-guided Focused Ultrasound as Organ-Sparing Treatment for Testicular Cancer

    Science.gov (United States)

    Staruch, Robert; Curiel, Laura; Chopra, Rajiv; Hynynen, Kullervo

    2009-04-01

    High cure rates for testicular cancer have prompted interest in organ-sparing surgery for patients with bilateral disease or single testis. Focused ultrasound (FUS) ablation could offer a noninvasive approach to organ-sparing surgery. The objective of this study was to determine the feasibility of using MR thermometry to guide organ-sparing focused ultrasound surgery in the testis. The testes of anesthetized rabbits were sonicated in several discrete locations using a single-element focused transducer operating at 2.787MHz. Focal heating was visualized with MR thermometry, using a measured PRF thermal coefficient of -0.0089±0.0003 ppm/° C. Sonications at 3.5-14 acoustic watts applied for 30 seconds produced maximum temperature elevations of 10-80° C, with coagulation verified by histology. Coagulation of precise volumes in the testicle is feasible with MRI-guided focused ultrasound. Variability in peak temperature for given sonication parameters suggests the need for online temperature feedback control.

  4. MR-guided focused ultrasound robot for performing experiments on large animals

    Science.gov (United States)

    Mylonas, N.; Damianou, C.

    2011-09-01

    Introduction: In this paper an experimental MRI-guided focused ultrasound robot for large animals is presented. Materials and methods: A single element spherically focused transducer of 4 cm diameter, focusing at 10 cm and operating at 1 MHz was used. A positioning device was developed in order to scan the ultrasound transducer for performing MR-guided focused ultrasound experiments in large animals such as pig, sheep and dog. The positioning device incorporates only MRI compatible materials such as piezoelectric motors, Acrylonitrile Butadiene Styrene (ABS) plastic, brass screws, and brass pulleys. The system is manufactured automatically using a rapid prototyping system. Results: The system was tested successfully in a number of animals for various tasks (creation of single lesions, creation of overlapping lesions, and MR compatibility). Conclusions: A simple, cost effective, portable positioning device has been developed which can be used in virtually any clinical MRI scanner since it can be sited on the scanner's table. The propagation of HIFU can be via a lateral or superior-inferior approach. This system has the potential to be marketed as a cost effective solution for performing experiments in small and large animals.

  5. Mid-wave infrared narrow bandwidth guided mode resonance notch filter.

    Science.gov (United States)

    Zhong, Y; Goldenfeld, Z; Li, K; Streyer, W; Yu, L; Nordin, L; Murphy, N; Wasserman, D

    2017-01-15

    We have designed, fabricated, and characterized a guided mode resonance notch filter operating in the technologically vital mid-wave infrared (MWIR) region of the electromagnetic spectrum. The filter provides a bandstop at λ≈4.1  μm, with a 12 dB extinction on resonance. In addition, we demonstrate a high transmission background (>80%), less than 6% transmission on resonance, and an ultra-narrow bandwidth transmission notch (10  cm-1). Our filter is optically characterized using angle- and polarization-dependent Fourier transform infrared spectroscopy, and simulated using rigorous coupled-wave analysis (RCWA) with excellent agreement between simulations and our experimental results. Using our RCWA simulations, we are able to identify the optical modes associated with the transmission dips of our filter. The presented structure offers a potential route toward narrow-band laser filters in the MWIR.

  6. Optimizing MR imaging-guided navigation for focused ultrasound interventions in the brain

    Science.gov (United States)

    Werner, B.; Martin, E.; Bauer, R.; O'Gorman, R.

    2017-03-01

    MR imaging during transcranial MR imaging-guided Focused Ultrasound surgery (tcMRIgFUS) is challenging due to the complex ultrasound transducer setup and the water bolus used for acoustic coupling. Achievable image quality in the tcMRIgFUS setup using the standard body coil is significantly inferior to current neuroradiologic standards. As a consequence, MR image guidance for precise navigation in functional neurosurgical interventions using tcMRIgFUS is basically limited to the acquisition of MR coordinates of salient landmarks such as the anterior and posterior commissure for aligning a stereotactic atlas. Here, we show how improved MR image quality provided by a custom built MR coil and optimized MR imaging sequences can support imaging-guided navigation for functional tcMRIgFUS neurosurgery by visualizing anatomical landmarks that can be integrated into the navigation process to accommodate for patient specific anatomy.

  7. MO-DE-202-01: Image-Guided Focused Ultrasound Surgery and Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Farahani, K. [National Cancer Institute (United States)

    2016-06-15

    At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques. The four speakers are: Keyvan Farahani, “Image-guided focused ultrasound surgery and therapy” Jeffrey H. Siewerdsen, “Advances in image registration and reconstruction for image-guided neurosurgery” Tina Kapur, “Image-guided surgery and interventions in the advanced multimodality image-guided operating (AMIGO) suite” Raj Shekhar, “Multimodality image-guided interventions: Multimodality for the rest of us” Learning Objectives: Understand the principles and applications of HIFU in surgical ablation. Learn about recent advances in 3D–2D and 3D deformable image registration in support of surgical safety and precision. Learn about recent advances in model-based 3D image reconstruction in application to intraoperative 3D imaging. Understand the multi-modality imaging technologies and clinical applications investigated in the AMIGO suite. Understand the emerging need and techniques to implement multi-modality image guidance in surgical applications such as neurosurgery, orthopaedic surgery, vascular surgery, and interventional radiology. Research supported by the NIH and Siemens Healthcare.; J. Siewerdsen; Grant Support - National Institutes of Health; Grant Support - Siemens Healthcare; Grant Support - Carestream Health; Advisory Board - Carestream Health; Licensing Agreement - Carestream Health; Licensing Agreement - Elekta Oncology.; T. Kapur, P41EB015898; R. Shekhar, Funding: R42CA137886 and R41CA192504

  8. Investigation of therapy improvement using real-time photoacoustic imaging guided high intensity focused ultrasound

    Science.gov (United States)

    Cui, Huizhong

    There are a lot of risks in cancer treatment by invasive surgery, such as bleeding, wound infection, and long recovery time, etc. Therefore, there is great need for minimally- or non-invasive treatment. High intensity focused ultrasound (HIFU) is a rapidly growing and truly non-invasive technology. It has been widely used in therapeutic applications, such as rapid tissue heating and tissue ablation. With proper imaging guidance, HIFU treatment can be performed totally noninvasively. Currently, ultrasound imaging-guided HIFU has been extensively studied. However, ultrasound imaging guidance is less precise because of the relatively low imaging contrast, sensitivity, and specificity for noninvasive detection. In this study, we employed photoacoustic imaging (PAI) technique, which has been developed a novel promising imaging technique for early cancer detection, to guide HIFU treatment. The goal of this study is to investigate the feasibility of PAI to guide, monitor in real time and enhance the HIFU therapy. In this dissertation, as the first step, the integrated PAI and HIFU system had been shown to have the feasibility to guide HIFU both ex vivo and in vivo. Then, the system was improved and developed to a real-time PAI-guided HIFU system. It is demonstrated that the sensitivity of PA detection for HIFU lesion is very high and the saturation of PA signals can be used as the indicator for tissue coagulation. During the temperature measurement using this system, laser-enhanced HIFU heating was found. Thus, we further investigated the laser enhanced technique in both HIFU heating and pulsed HIFU thrombolysis. In the HIFU therapy, laser light was employed to illuminate the sample concurrently with HIFU radiation. The resulting cavitation was detected with a passive cavitation detector. We demonstrated that concurrent light illumination during HIFU has the potential to significantly enhance HIFU by reducing cavitation threshold.

  9. Achieving ultranarrow graphene perfect absorbers by exciting guided-mode resonance of one-dimensional photonic crystals

    National Research Council Canada - National Science Library

    Long, Yongbing; Shen, Liang; Xu, Haitao; Deng, Haidong; Li, Yuanxing

    2016-01-01

    Graphene perfect absorbers with ultranarrow bandwidth are numerically proposed by employing a subwavelength dielectric grating to excite the guided-mode resonance of one-dimensional photonic crystals (1DPCs...

  10. Proton emission from resonant laser absorption and self-focusing effects from hydrogenated structures

    Science.gov (United States)

    Cutroneo, M.; Torrisi, L.; Margarone, D.; Picciotto, A.

    2013-05-01

    Effects of resonant absorption and self-focusing are investigated by using fast and intense laser pulses. The ion emission and acceleration in the non-equilibrium laser-generated plasma are investigated at low and high intensities, from 1010 up to about 1016 W/cm2. The properties of plasma are strongly dependent on the time and space, laser intensity and wavelength. A special interest concerns the energetic and intense proton generation for the multiplicity use that proton beams have in different scientific fields (Nuclear Physics, Astrophysics, Bio-Medicine, Microelecronics, etc.). Investigations have been performed at INFN-LNS of Catania and at PALS Laboratory of Prague, by using thick and thin targets and different technique of ion analysis. The mechanisms of resonant absorption of the laser light, produced in special targets containing nanostructures with dimensions comparable with the laser wavelength, enhances the proton energy. The mechanisms of self-focusing, obtained by changing the laser focal distance from the target surface, increase the local intensity and consequently the high directional ion acceleration. Real-time ion detections were performed through Thomson parabola spectrometer (TPS), ion collectors (IC), SiC detectors and ion energy analyzer (IEA) employed in time-of-flight configuration (TOF). The energy and the amount of ions increase significantly when the two non-linear phenomena occurs, as will be described.

  11. Proton emission from resonant laser absorption and self-focusing effects from hydrogenated structures

    Energy Technology Data Exchange (ETDEWEB)

    Cutroneo, M., E-mail: mari.cutroneo@tiscali.it [Dip.di Fisica, Università di Messina, V. F. Stagno D’Alcontres 31, 98166 S. Agata (Italy); Torrisi, L. [Dip.di Fisica, Università di Messina, V. F. Stagno D’Alcontres 31, 98166 S. Agata (Italy); Margarone, D. [Institute of Physics, ASCR-PALS, Na Slovance 2, 18221 Prague 8 (Czech Republic); Picciotto, A. [Fondazione Bruno Kessler – IRST, Trento (Italy)

    2013-05-01

    Effects of resonant absorption and self-focusing are investigated by using fast and intense laser pulses. The ion emission and acceleration in the non-equilibrium laser-generated plasma are investigated at low and high intensities, from 10{sup 10} up to about 10{sup 16} W/cm{sup 2}. The properties of plasma are strongly dependent on the time and space, laser intensity and wavelength. A special interest concerns the energetic and intense proton generation for the multiplicity use that proton beams have in different scientific fields (Nuclear Physics, Astrophysics, Bio-Medicine, Microelecronics, etc.). Investigations have been performed at INFN-LNS of Catania and at PALS Laboratory of Prague, by using thick and thin targets and different technique of ion analysis. The mechanisms of resonant absorption of the laser light, produced in special targets containing nanostructures with dimensions comparable with the laser wavelength, enhances the proton energy. The mechanisms of self-focusing, obtained by changing the laser focal distance from the target surface, increase the local intensity and consequently the high directional ion acceleration. Real-time ion detections were performed through Thomson parabola spectrometer (TPS), ion collectors (IC), SiC detectors and ion energy analyzer (IEA) employed in time-of-flight configuration (TOF). The energy and the amount of ions increase significantly when the two non-linear phenomena occurs, as will be described.

  12. Sampling strategies for subsampled segmented EPI PRF thermometry in MR guided high intensity focused ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Odéen, Henrik, E-mail: h.odeen@gmail.com; Diakite, Mahamadou [Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84108 and Department of Radiology, University of Utah, Salt Lake City, Utah 84108 (United States); Todd, Nick; Minalga, Emilee; Payne, Allison; Parker, Dennis L. [Department of Radiology, University of Utah, Salt Lake City, Utah 84108 (United States)

    2014-09-15

    Purpose: To investigate k-space subsampling strategies to achieve fast, large field-of-view (FOV) temperature monitoring using segmented echo planar imaging (EPI) proton resonance frequency shift thermometry for MR guided high intensity focused ultrasound (MRgHIFU) applications. Methods: Five different k-space sampling approaches were investigated, varying sample spacing (equally vs nonequally spaced within the echo train), sampling density (variable sampling density in zero, one, and two dimensions), and utilizing sequential or centric sampling. Three of the schemes utilized sequential sampling with the sampling density varied in zero, one, and two dimensions, to investigate sampling the k-space center more frequently. Two of the schemes utilized centric sampling to acquire the k-space center with a longer echo time for improved phase measurements, and vary the sampling density in zero and two dimensions, respectively. Phantom experiments and a theoretical point spread function analysis were performed to investigate their performance. Variable density sampling in zero and two dimensions was also implemented in a non-EPI GRE pulse sequence for comparison. All subsampled data were reconstructed with a previously described temporally constrained reconstruction (TCR) algorithm. Results: The accuracy of each sampling strategy in measuring the temperature rise in the HIFU focal spot was measured in terms of the root-mean-square-error (RMSE) compared to fully sampled “truth.” For the schemes utilizing sequential sampling, the accuracy was found to improve with the dimensionality of the variable density sampling, giving values of 0.65 °C, 0.49 °C, and 0.35 °C for density variation in zero, one, and two dimensions, respectively. The schemes utilizing centric sampling were found to underestimate the temperature rise, with RMSE values of 1.05 °C and 1.31 °C, for variable density sampling in zero and two dimensions, respectively. Similar subsampling schemes

  13. Sampling strategies for subsampled segmented EPI PRF thermometry in MR guided high intensity focused ultrasound

    Science.gov (United States)

    Odéen, Henrik; Todd, Nick; Diakite, Mahamadou; Minalga, Emilee; Payne, Allison; Parker, Dennis L.

    2014-01-01

    Purpose: To investigate k-space subsampling strategies to achieve fast, large field-of-view (FOV) temperature monitoring using segmented echo planar imaging (EPI) proton resonance frequency shift thermometry for MR guided high intensity focused ultrasound (MRgHIFU) applications. Methods: Five different k-space sampling approaches were investigated, varying sample spacing (equally vs nonequally spaced within the echo train), sampling density (variable sampling density in zero, one, and two dimensions), and utilizing sequential or centric sampling. Three of the schemes utilized sequential sampling with the sampling density varied in zero, one, and two dimensions, to investigate sampling the k-space center more frequently. Two of the schemes utilized centric sampling to acquire the k-space center with a longer echo time for improved phase measurements, and vary the sampling density in zero and two dimensions, respectively. Phantom experiments and a theoretical point spread function analysis were performed to investigate their performance. Variable density sampling in zero and two dimensions was also implemented in a non-EPI GRE pulse sequence for comparison. All subsampled data were reconstructed with a previously described temporally constrained reconstruction (TCR) algorithm. Results: The accuracy of each sampling strategy in measuring the temperature rise in the HIFU focal spot was measured in terms of the root-mean-square-error (RMSE) compared to fully sampled “truth.” For the schemes utilizing sequential sampling, the accuracy was found to improve with the dimensionality of the variable density sampling, giving values of 0.65 °C, 0.49 °C, and 0.35 °C for density variation in zero, one, and two dimensions, respectively. The schemes utilizing centric sampling were found to underestimate the temperature rise, with RMSE values of 1.05 °C and 1.31 °C, for variable density sampling in zero and two dimensions, respectively. Similar subsampling schemes

  14. Patient selection guidelines in MR-guided focused ultrasound surgery of uterine fibroids: a pictorial guide to relevant findings in screening pelvic MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sang-Wook; Kim, Kyoung Ah [Pochon CHA University Bundang CHA General Hospital, Department of Diagnostic Radiology, College of Medicine, Gyunggi-do (Korea); Lee, Chan; Na, Young-Jeong; Jung, Sang-Geun; Kim, Seung-Jo [Pochon CHA University Bundang CHA General Hospital, Comprehensive Gynecologic Cancer Center, College of Medicine, Gyunggi-do (Korea); Cha, Sun Hee [Pochon CHA University Bundang CHA General Hospital, Department of Obstetrics and Gynecology, College of Medicine, Gyunggi-do (Korea); Yu, Jeong-Sik [YongDong Severance Hospital, Department of Diagnostic Radiology, Yonsei University College of Medicine, Seoul (Korea)

    2008-12-15

    Uterine leiomyomas (fibroids), the most common benign tumor in women of childbearing age, can cause symptoms including dysmenorrhea, menorrhagia, urinary symptoms, pain and infertility. Hysterectomy is a common approach to treating uterine fibroids, and less invasive surgical approaches such as myomectomy and uterine artery embolization also have been shown to alleviate symptoms. Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is the only totally non-invasive surgical approved method for treating uterine fibroids. In clinical trials, MRgFUS resulted in significant relief of uterine fibroid symptoms. The safe and effective use of MRgFUS is affected by fibroid type and location, position relative to adjacent anatomical structures and the presence of co-existent pelvic disease. Additionally, successful outcomes with MRgFUS have been correlated with the volume of fibroids ablated during the procedure. Thus, selection of patients in whom sufficient fibroid volumes can be treated safely using the MRgFUS system is critical for successful outcomes. The MR images in this pictorial essay provide examples of uterine fibroids for which MRgFUS should be considered and is designed to facilitate the selection of patients for whom MRgFUS is most likely to provide sustained symptom relief. (orig.)

  15. Stem Cell Labeling with Superparamagnetic Iron Oxide Nanoparticles Using Focused Ultrasound and Magnetic Resonance Imaging Tracking.

    Science.gov (United States)

    Lei, Hulong; Nan, Xiang; Wang, Zhiyong; Gao, Lin; Xie, Lisi; Zou, Chao; Wan, Qian; Pan, Di; Beauchamp, Norman; Yang, Xiaoming; Matula, Thomas; Qiu, Bensheng

    2015-04-01

    Magnetosonoporation (MSP) is a relatively safe and efficient approach for instant MR stem cell labeling. In this study, the physical and magnetic properties of different formulations of synthesized superparamagnetic iron oxide nanoparticles (SPION) were characterized. Then, a "closed" MSP apparatus using focused ultrasound was designed and the feasibility of MSP stem cell labeling using focused ultrasound was validated by evaluating the proliferation, migration and differentiation of the magnetically labeled cells. Subsequently, MSP/SPION labeled neural stem cells (NSCs) were transplanted into the contralateral striatum of glioma-bearing nude mice, and their migration was monitored using magnetic resonance imaging (MRI) in vivo. The results indicated that SPION-1 with the largest size (28.43 ± 9.55 nm) had the highest T2 relaxivity (136.62 Fe mM(-1) S(-1)) and the best MRI contrast effect. Without additional transfection reagents, NSCs were labeled with SPION using focused ultrasound in vitro and the safety of MSP stem cell labeling was validated with the optimized MSP technique. Finally, confirmed by histological evaluation, pronounced signal attenuation on T2-weighted images demonstrated the intracranial tumor tropism of NSCs could be monitored non-invasively by MRI. In conclusion, MSP cell labeling using focused ultrasound is a promising technique and the "closed" device is feasible, convenient and safe for instant magnetic stem cell labeling and MRI cell tracking.

  16. Ultrasound-guided high-intensity focused ultrasound treatment for abdominal wall endometriosis: Preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yang [Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China); Wang Wei, E-mail: wangyang301301@yahoo.com.cn [Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China); Wang Longxia; Wang Junyan; Tang Jie [Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 (China)

    2011-07-15

    Purpose: To evaluate the safety and therapeutic efficacy of ultrasound (US)-guided high-intensity focused ultrasound (HIFU) ablation for the treatment of abdominal wall endometriosis (AWE). Materials and methods: Twenty-one consecutive patients with AWE were treated as outpatients by US-guided HIFU ablation under conscious sedation. The median size of the AWE was 2.4 cm (range 1.0-5.3 cm). An acoustic power of 200-420 W was used, intermittent HIFU exposure of 1 s was applied. Treatment was considered complete when the entire nodule and its nearby 1 cm margin become hyperechoic on US. Pain relief after HIFU ablation was observed and the treated nodule received serial US examinations during follow-up. Results: All AWE was successfully ablated after one session of HIFU ablation, the ablation time lasted for 5-48 min (median 13 min), no major complications occurred. The cyclic pain disappeared in all patients during a mean follow-up of 18.7 months (range 3-31 months). The treated nodules gradually shank over time, 16 nodules became unnoticeable on US during follow-up. Conclusion: US-guided HIFU ablation appears to be safe and effective for the treatment of AWE.

  17. Methodology on quantification of sonication duration for safe application of MR guided focused ultrasound for liver tumour ablation.

    Science.gov (United States)

    Mihcin, Senay; Karakitsios, Ioannis; Le, Nhan; Strehlow, Jan; Demedts, Daniel; Schwenke, Michael; Haase, Sabrina; Preusser, Tobias; Melzer, Andreas

    2017-12-01

    Magnetic Resonance Guided Focused Ultrasound (MRgFUS) for liver tumour ablation is a challenging task due to motion caused by breathing and occlusion due the ribcage between the transducer and the tumour. To overcome these challenges, a novel system for liver tumour ablation during free breathing has been designed. The novel TRANS-FUSIMO Treatment System (TTS, EUFP7) interacts with a Magnetic Resonance (MR) scanner and a focused ultrasound transducer to sonicate to a moving target in liver. To meet the requirements of ISO 13485; a quality management system for medical device design, the system needs to be tested for certain process parameters. The duration of sonication and, the delay after the sonication button is activated, are among the parameters that need to be quantified for efficient and safe ablation of tumour tissue. A novel methodology is developed to quantify these process parameters. A computerised scope is programmed in LabVIEW to collect data via hydrophone; where the coordinates of fiber-optic sensor assembly was fed into the TRANS-FUSIMO treatment software via Magnetic Resonance Imaging (MRI) to sonicate to the tip of the sensor, which is synchronised with the clock of the scope, embedded in a degassed water tank via sensor assembly holder. The sonications were executed for 50 W, 100 W, 150 W for 10 s to quantify the actual sonication duration and the delay after the emergency stop by two independent operators for thirty times. The deviation of the system from the predefined specs was calculated. Student's-T test was used to investigate the user dependency. The duration of sonication and the delay after the sonication were quantified successfully with the developed method. TTS can sonicate with a maximum deviation of 0.16 s (Std 0.32) from the planned duration and with a delay of 14 ms (Std 0.14) for the emergency stop. Student's T tests indicate that the results do not depend on operators (p > .05). The evidence obtained via this

  18. Improving CT-guided transthoracic biopsy of mediastinal lesions by diffusion-weighted magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Marcos Duarte; TyngI, Chiang Cheng; Bitencourt, Almir Galvao Vieira; Gross, Jefferson Luiz; Zurstrassen, Charles Edouard, E-mail: marcosduarte500@gmail.com [AC Camargo Cancer Center, Sao Paulo, SP (Brazil); Hochhegger, Bruno [Universidade Federal de Ciencias da Saude de Porto Alegre (UFCSPA), RS (Brazil). Dept. de Radiologia; Benveniste, Marcelo Felipe Kuperman; Odisio, Bruno Calazans [University of Texas, MD Anderson Cancer Center, Houston, TX (United States); Marchiori, Edson [Universidade Federal do Rio de Janeiro (UFRJ), Petropolis, RJ (Brazil)

    2014-11-15

    Objectives: to evaluate the preliminary results obtained using diffusion-weighted magnetic resonance imaging and the apparent diffusion coefficient for planning computed tomography-guided biopsies of selected mediastinal lesions. Methods: eight patients with mediastinal lesions suspicious for malignancy were referred for computed tomography-guided biopsy. Diffusion-weighted magnetic resonance imaging and apparent diffusion coefficient measurement were performed to assist in biopsy planning with diffusion/computed tomography fused images. We selected mediastinal lesions that could provide discordant diagnoses depending on the biopsy site, including large heterogeneous masses, lesions associated with lung atelectasis or consolidation, lesions involving large mediastinal vessels and lesions for which the results of biopsy using other methods and histopathological examination were divergent from the clinical and radiological suspicion. Results: in all cases, the biopsy needle was successfully directed to areas of higher signal intensity on diffusion weighted sequences and the lowest apparent diffusion coefficient within the lesion (mean, 0.8 [range, 0.6–1.1]610{sup -3} mm{sup 2}/s), suggesting high cellularity. All biopsies provided adequate material for specific histopathological diagnoses of four lymphomas, two sarcomas and two thymoma s. Conclusion: functional imaging tools, such as diffusion-weighted imaging and the apparent diffusion coefficient, are promising for implementation in noninvasive and imaging-guided procedures. However, additional studies are needed to confirm that mediastinal biopsy can be improved with these techniques. (author)

  19. High-intensity focused ultrasound (HIFU) array system for image-guided ablative therapy (IGAT)

    Science.gov (United States)

    Kaczkowski, Peter J.; Keilman, George W.; Cunitz, Bryan W.; Martin, Roy W.; Vaezy, Shahram; Crum, Lawrence A.

    2003-06-01

    Recent interest in using High Intensity Focused Ultrasound (HIFU) for surgical applications such as hemostasis and tissue necrosis has stimulated the development of image-guided systems for non-invasive HIFU therapy. Seeking an all-ultrasound therapeutic modality, we have developed a clinical HIFU system comprising an integrated applicator that permits precisely registered HIFU therapy delivery and high quality ultrasound imaging using two separate arrays, a multi-channel signal generator and RF amplifier system, and a software program that provides the clinician with a graphical overlay of the ultrasound image and therapeutic protocol controls. Electronic phasing of a 32 element 2 MHz HIFU annular array allows adjusting the focus within the range of about 4 to 12 cm from the face. A central opening in the HIFU transducer permits mounting a commercial medical imaging scanhead (ATL P7-4) that is held in place within a special housing. This mechanical fixture ensures precise coaxial registration between the HIFU transducer and the image plane of the imaging probe. Recent enhancements include development of an acoustic lens using numerical simulations for use with a 5-element array. Our image-guided therapy system is very flexible and enables exploration of a variety of new HIFU therapy delivery and monitoring approaches in the search for safe, effective, and efficient treatment protocols.

  20. Far field subwavelength imaging and focusing using a wire medium based resonant metalens

    CERN Document Server

    Lemoult, Fabrice; Fink, Mathias

    2010-01-01

    This is the second article in a series of two dealing with the concept of "resonant metalens" we introduced recently [Phys. Rev. Lett. 104, 203901 (2010)]. It is a new type of lens capable of coding in time and radiating efficiently in the far field region sub-diffraction information of an object. A proof of concept of such a lens is performed in the microwave range, using a medium made out of a square lattice of parallel conducting wires with finite length. We investigate a sub-wavelength focusing scheme with time reversal and demonstrate experimentally spots with focal widths of {\\lambda}/25. Through a cross-correlation based imaging procedure we show an image reconstruction with a resolution of {\\lambda}/80. Eventually we discuss the limitations of such a lens which reside essentially in losses.

  1. First clinical experience with a dedicated MRI-guided high-intensity focused ultrasound system for breast cancer ablation

    Energy Technology Data Exchange (ETDEWEB)

    Merckel, Laura G.; Knuttel, Floor M.; Peters, Nicky H.G.M.; Mali, Willem P.T.M.; Bosch, Maurice A.A.J. van den [University Medical Center Utrecht, Department of Radiology, HP E 01.132, Utrecht (Netherlands); Deckers, Roel; Moonen, Chrit T.W.; Bartels, Lambertus W. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands); Dalen, Thijs van [Diakonessenhuis Utrecht, Department of Surgery, Utrecht (Netherlands); Schubert, Gerald [Philips Healthcare, Best (Netherlands); Weits, Teun [Diakonessenhuis Utrecht, Department of Radiology, Utrecht (Netherlands); Diest, Paul J. van [University Medical Center Utrecht, Department of Pathology, Utrecht (Netherlands); Vaessen, Paul H.H.B. [University Medical Center Utrecht, Department of Anesthesiology, Utrecht (Netherlands); Gorp, Joost M.H.H. van [Diakonessenhuis Utrecht, Department of Pathology, Utrecht (Netherlands)

    2016-11-15

    To assess the safety and feasibility of MRI-guided high-intensity focused ultrasound (MR-HIFU) ablation in breast cancer patients using a dedicated breast platform. Patients with early-stage invasive breast cancer underwent partial tumour ablation prior to surgical resection. MR-HIFU ablation was performed using proton resonance frequency shift MR thermometry and an MR-HIFU system specifically designed for breast tumour ablation. The presence and extent of tumour necrosis was assessed by histopathological analysis of the surgical specimen. Pearson correlation coefficients were calculated to assess the relationship between sonication parameters, temperature increase and size of tumour necrosis at histopathology. Ten female patients underwent MR-HIFU treatment. No skin redness or burns were observed in any of the patients. No correlation was found between the applied energy and the temperature increase. In six patients, tumour necrosis was observed with a maximum diameter of 3-11 mm. In these patients, the number of targeted locations was equal to the number of areas with tumour necrosis. A good correlation was found between the applied energy and the size of tumour necrosis at histopathology (Pearson = 0.76, p = 0.002). Our results show that MR-HIFU ablation with the dedicated breast system is safe and results in histopathologically proven tumour necrosis. (orig.)

  2. Magnetic Resonance-Guided Laser Induced Thermal Therapy for Glioblastoma Multiforme: A Review

    Directory of Open Access Journals (Sweden)

    Sarah E. Norred

    2014-01-01

    Full Text Available Magnetic resonance-guided laser induced thermotherapy (MRgLITT has become an increasingly relevant therapy for tumor ablation due to its minimally invasive approach and broad applicability across many tissue types. The current state of the art applies laser irradiation via cooled optical fiber applicators in order to generate ablative heat and necrosis in tumor tissue. Magnetic resonance temperature imaging (MRTI is used concurrently with this therapy to plan treatments and visualize tumor necrosis. Though application in neurosurgery remains in its infancy, MRgLITT has been found to be a promising therapy for many types of brain tumors. This review examines the current use of MRgLITT with regard to the special clinical challenge of glioblastoma multiforme and examines the potential applications of next-generation nanotherapy specific to the treatment of glioblastoma.

  3. Bandwidth tunable guided-mode resonance filter using contact coupled gratings at oblique incidence

    Science.gov (United States)

    Sang, Tian; Wang, Yueke; Li, Junlang; Zhou, Jianyu; Jiang, Wenwen; Wang, Jicheng; Chen, Guoqing

    2017-01-01

    A novel bandwidth tunable guided-mode resonance filter (GMRF) is proposed based on the contact coupled gratings (CCGs) with the absentee layers at oblique incidence. The design principle of the CCGs with double absentee layers is presented. The lateral shift of the CCGs changes the magnetic field distributions of the waveguide mode in the grating cavity and the surface-confined mode at the cover/grating interface thus facilitates the dynamic control of both the spectral and angular bandwidth of the GMRF. The resonance locations are almost immune to the variation of the lateral shift of the CCGs. The sideband level of the GMRF is almost unaffected by the lateral shift due to the Brewster AR effect. The resonance peak red-shifts quasi-linearly as the incident angle is increased, and the resonance wavelength can be selected by merely tuning the incident angle. The tunable ranges of both the spectral and angular bandwidth can be significantly enhanced by increasing the refractive-index contrast. Low-sideband reflection with controllable bandwidth at 650 nm is designed to demonstrate this concept.

  4. Magnetic resonance imaging guided treatment of equine distal interphalangeal joint collateral ligaments: 2009-2014

    Directory of Open Access Journals (Sweden)

    Nathaniel A. White

    2016-09-01

    Full Text Available Objectives: To determine the success of treating distal interphalangeal joint collateral ligament (DIJCL desmopathy using magnetic resonance imaging (MRI guided ligament injection. Methods: Medical records of 13 adult horses diagnosed with DIJCL desmopathy using low field MRI and treated by MRI guided ligament injection of mesenchymal stem cells and/or platelet rich plasma were reviewed. Information collected included signalment, MRI diagnosis, treatment type, time to resolution of lameness and level of exercise after treatment. Results: Collateral ligament inflammation was diagnosed as a cause of lameness in 13 horses. MRI was used to guide the injection of the injured DIJCL. All lameness attributed to DIJCL desmopathy resolved with the resulting level of performance at expected (10 or less than expected (3. Conclusions and Clinical Relevance: Injection of the DIJCL can be completed in horses standing in a low field magnet guided by MRI as previously demonstrated in cadaver specimens. Administration of stem cells or PRP appears useful as a treatment for DIJCL desmopathy.

  5. Polarization-independent beam deflection and focusing with dielectric non-resonant metasurfaces

    Science.gov (United States)

    Su, Xiaofang; Li, Guanhai; Yang, Hui; Zhao, Zengyue; Yu, Feilong; Chen, Xiaoshuang

    2017-08-01

    Metasurfaces, constructed from function-driven artificial meta-cells, possess great flexibility in tuning effective electric permittivity and magnetic permeability, leading to excellent performance on the manipulation of electromagnetic waves. Here, polarization-independent dielectric metasurfaces are presented as beam deflectors and meta-lenses working on telecommunication wavelength based on non-resonant metamolecules. A conversion efficiency as high as 70.5% is achieved when beam deflection angle θ  =  18.45°. With precisely designed parameters, a planar lens with the focal length of 30.85 µm shows that focusing efficiency as high as 47.3% is realized. The meta-lens yields a NA  =  0.63 and a full-width at half-maximum (FWHM)  =  1.64 µm at 1.55 µm. With broadband and wide-angle focusing properties, the polarization-insensitive metasurfaces promise great applications in high sensitivity single photon detector and other opto-electronic integrated devices.

  6. Application of MR-guided focused pulsed ultrasound for destroying clots in vitro using thrombolytic drugs

    Science.gov (United States)

    Hadjisavvas, V.; Ioannides, K.; Damianou, C.

    2011-09-01

    In this paper an MR-guided focused pulsed ultrasound system for the treatment of stroke using thrombolytic drugs in a model in vitro is presented. A single element spherically focused transducer of 5 cm diameter; focusing at 10 cm and operating at 0.5 MHz or 1 MHz was used. The transducer was mounted in an MR compatible robot. The artery was modelled using a silicone tube. Tissue was modelled using polyaclylimide gel. Coagulated blood was used to model thrombus. A thermocouple was placed in the thrombus in order to measure the thrombus temperature. The effect of power, beam, and frequency was investigated. The goal was to maintain a temperature increase of less than 1 °C during the application of pulse ultrasound (called safe temperature). With the application of ultrasound alone there was no notable destruction of the thrombus. With the combination of ultrasound and thrombolytic drugs destruction occurred after 60 mins of pulse exposure (PRF = 1 s, duty factor = 10%, and with thrombus placed at 1 cm deep in the tissue). This simple in vitro model was proven very successful for evaluating MRgFUS as a modality for treating stroke. In the future we plan to apply this treatment protocol in live animals and humans.

  7. Photoacoustic-guided focused ultrasound for accurate visualization of brachytherapy seeds with the photoacoustic needle

    Science.gov (United States)

    Singh, Mithun Kuniyil Ajith; Parameshwarappa, Vinay; Hendriksen, Ellen; Steenbergen, Wiendelt; Manohar, Srirang

    2016-12-01

    An important problem in minimally invasive photoacoustic (PA) imaging of brachytherapy seeds is reflection artifacts caused by the high signal from the optical fiber/needle tip reflecting off the seed. The presence of these artifacts confounds interpretation of images. In this letter, we demonstrate a recently developed concept called photoacoustic-guided focused ultrasound (PAFUSion) for the first time in the context of interstitial illumination PA imaging to identify and remove reflection artifacts. In this method, ultrasound (US) from the transducer is focused on the region of the optical fiber/needle tip identified in a first step using PA imaging. The image developed from the US diverging from the focus zone at the tip region visualizes only the reflections from seeds and other acoustic inhomogeneities, allowing identification of the reflection artifacts of the first step. These artifacts can then be removed from the PA image. Using PAFUSion, we demonstrate reduction of reflection artifacts and thereby improved interstitial PA visualization of brachytherapy seeds in phantom and ex vivo measurements on porcine tissue.

  8. Type of tunable guided-mode resonance filter based on electro-optic characteristic of polymer-dispersed liquid crystal.

    Science.gov (United States)

    Wang, Qi; Zhang, Dawei; Huang, Yuanshen; Ni, Zhengji; Chen, Jiabi; Zhong, Yangwan; Zhuang, Songlin

    2010-04-15

    A narrowband guided-mode resonance filter (GMRF) incorporating polymer-dispersed liquid crystal (PDLC) is designed. Simulating the characteristics of the filter with rigorous coupled-wave analysis, we find that the resonance wavelength of the new kind of GMRF can be tuned from 672.4 to 698.4 nm by varying the refractive index of the PDLC layer with the applied voltage. Furthermore, the resonance wavelengths vary in a linear fashion with respect to the refractive index of the PDLC layer. Therefore, the desired resonance wavelength can be conveniently selected and tuned in a tuning range of 26 nm by using the applied voltage.

  9. Preclinical MRI-Guided Focused Ultrasound: A Review of Systems and Current Practices.

    Science.gov (United States)

    Ellens, Nicholas P K; Partanen, Ari

    2017-01-01

    Effective preclinical research is a vital component in the development of MRI-guided focused ultrasound (MRgFUS) and its translation to clinic. In this review, we seek to outline the challenges at hand for effective preclinical research, survey different solutions, and underline best practices. Furthermore, we summarize efforts to build and characterize dedicated preclinical MRgFUS equipment, including lab prototypes and available commercial products. Finally, we discuss constraints and considerations specific to using clinical MRgFUS equipment in preclinical research. Specifically, we examine additional hardware that has been used to adapt clinical MRgFUS equipment to better position, constrain, and image preclinical subjects, as well as software solutions that have been used to extend the potential and capabilities of clinical devices.

  10. Pre-Clinical MRI-Guided Focused Ultrasound: A Review of Systems and Current Practices.

    Science.gov (United States)

    Ellens, Nicholas; Partanen, Ari

    2016-09-13

    Effective pre-clinical research is a vital component in the development of MRI-guided focused ultrasound (MRgFUS) and its translation to clinic. In this review we seek to outline the challenges at hand for effective pre-clinical research, survey different solutions, and underline best practices. Furthermore, we summarize efforts to build and characterize dedicated pre-clinical MRgFUS equipment, including lab prototypes and available commercial products. Finally, we discuss constraints and considerations specific to using clinical MRgFUS equipment in preclinical research. Specifically, we examine additional hardware that has been used to adapt clinical MRgFUS equipment to better position, constrain, and image pre-clinical subjects, as well as software solutions that have been used to extend the potential and capabilities of clinical devices.

  11. Pediatric Sarcomas Are Targetable by MR-Guided High Intensity Focused Ultrasound (MR-HIFU): Anatomical Distribution and Radiological Characteristics.

    Science.gov (United States)

    Shim, Jenny; Staruch, Robert M; Koral, Korgun; Xie, Xian-Jin; Chopra, Rajiv; Laetsch, Theodore W

    2016-10-01

    Despite intensive therapy, children with metastatic and recurrent sarcoma or neuroblastoma have a poor prognosis. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is a noninvasive technique allowing the delivery of targeted ultrasound energy under MR imaging guidance. MR-HIFU may be used to ablate tumors without ionizing radiation or target chemotherapy using hyperthermia. Here, we evaluated the anatomic locations of tumors to assess the technical feasibility of MR-HIFU therapy for children with solid tumors. Patients with sarcoma or neuroblastoma with available cross-sectional imaging were studied. Tumors were classified based on the location and surrounding structures within the ultrasound beam path as (i) not targetable, (ii) completely or partially targetable with the currently available MR-HIFU system, and (iii) potentially targetable if a respiratory motion compensation technique was used. Of the 121 patients with sarcoma and 61 patients with neuroblastoma, 64% and 25% of primary tumors were targetable at diagnosis, respectively. Less than 20% of metastases at diagnosis or relapse were targetable for both sarcoma and neuroblastoma. Most targetable lesions were located in extremities or in the pelvis. Respiratory motion compensation may increase the percentage of targetable tumors by 4% for sarcomas and 10% for neuroblastoma. Many pediatric sarcomas are localized at diagnosis and are targetable by current MR-HIFU technology. Some children with neuroblastoma have bony tumors targetable by MR-HIFU at relapse, but few newly diagnosed children with neuroblastoma have tumors amenable to MR-HIFU therapy. Clinical trials of MR-HIFU should focus on patients with anatomically targetable tumors. © 2016 Wiley Periodicals, Inc.

  12. On the effect of broadband, multi-angular excitation and detection in guided-mode resonance biosensors

    Science.gov (United States)

    Threm, Daniela; Jahns, Sabrina; Nazirizadeh, Yousef; Ziegler, Martin; Hansen, Mirko; Kohlstedt, Hermann; Adam, Jost; Gerken, Martina

    2013-05-01

    Guided mode resonance biosensors are of emerging interest as they allow integration on chip with fabrication on mass scale. The guided mode resonances (GMRs), observed in the transmission or reflection spectrum, are sensitive to refractive index changes in the vicinity of the photonic crystal (PhC) surface. Standard measurement setups utilize a collecting lens, focusing the extracted light intensity onto a single-point photo detector. In order to achieve highly miniaturized devices, we consider the integration of planar emitting and detector structures, such as organic light emitting diodes (OLEDs) and organic photo detectors (OPDs), together with the PhC based biosensors, on a single chip. This approach, however, consequently leads to a broadband, multi-angular light excitation as well as to a broadband and multi-angular contribution to the OPD photon count. While GMR effects in PhC slabs with directional light sources have been widely studied, this lens-less scenario requires a deep understanding regarding the broadband and the angular influence of both incident and reflected or transmitted light. We performed finite-difference time-domain (FDTD) calculations for GMR effects in two-dimensional (2D) PhC slabs. We study the effects for broadband emission in the visible spectrum, together with an angular incident beam divergence of up to 80°. We verified the simulated results by performing angle-resolved spectral measurements with a light emitting diode (LED) in a macroscopic, lens-less setup. We further utilize this numerical setup to provide a deeper understanding of the modal behaviour of our proposed OLED and OPD-based integrated biosensor concept.

  13. Tunable Clamped–Guided Arch Resonators Using Electrostatically Induced Axial Loads

    KAUST Repository

    Alcheikh, Nouha

    2017-01-04

    We present a simulation and experimental investigation of bi-directional tunable in-plane clamped-guided arch microbeam resonators. Tensile and compressive axial forces are generated from a bi-directional electrostatic actuator, which modulates the microbeam stiffness, and hence changes its natural frequency to lower or higher values from its as-fabricated value. Several devices of various anchor designs and geometries are fabricated. We found that for the fabricated shallow arches, the effect of the curvature of the arch is less important compared to the induced axial stress from the axial load. We have shown that the first mode resonance frequency can be increased up to twice its initial value. Additionally, the third mode resonance frequency can be increased up to 30% of its initial value. These results can be promising as a proof-of-concept for the realization of wide-range tunable microresonators. The experimental results have been compared to finite-element simulations, showing good agreement among them.

  14. MRI-Guided Focused Ultrasound as a New Method of Drug Delivery

    Directory of Open Access Journals (Sweden)

    M. Thanou

    2013-01-01

    Full Text Available Ultrasound-mediated drug delivery under the guidance of an imaging modality can improve drug disposition and achieve site-specific drug delivery. The term focal drug delivery has been introduced to describe the focal targeting of drugs in tissues with the help of imaging and focused ultrasound. Focal drug delivery aims to improve the therapeutic profile of drugs by improving their specificity and their permeation in defined areas. Focused-ultrasound- (FUS- mediated drug delivery has been applied with various molecules to improve their local distribution in tissues. FUS is applied with the aid of microbubbles to enhance the permeability of bioactive molecules across BBB and improve drug distribution in the brain. Recently, FUS has been utilised in combination with MRI-labelled liposomes that respond to temperature increase. This strategy aims to “activate” nanoparticles to release their cargo locally when triggered by hyperthermia induced by FUS. MRI-guided FUS drug delivery provides the opportunity to improve drug bioavailability locally and therefore improve the therapeutic profiles of drugs. This drug delivery strategy can be directly translated to clinic as MRg FUS is a promising clinically therapeutic approach. However, more basic research is required to understand the physiological mechanism of FUS-enhanced drug delivery.

  15. Neutron intensity modulation and time-focusing with integrated Larmor and resonant frequency techniques

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Jinkui, E-mail: zhaoj@ornl.gov; Hamilton, William A.; Robertson, J. L.; Crow, Lowell [Instrument and Source Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Lee, Sung-Woo; Kang, Yoon W. [Research Accelerator Division, Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-09-14

    The analysis of neutron diffraction experiments often assumes that neutrons are elastically scattered from the sample. However, there is growing evidence that a significant fraction of the detected neutrons is in fact inelastically scattered, especially from soft materials and aqueous samples. Ignoring these inelastic contributions gives rise to inaccurate experimental results. To date, there has been no simple method with broad applicability for inelastic signal separation in neutron diffraction experiments. Here, we present a simple and robust method that we believe could be suited for this purpose. We use two radio frequency resonant spin flippers integrated with a Larmor precession field to modulate the neutron intensity and to encode the inelastic scattering information into the neutron data. All three components contribute to the spin encoding. The Larmor field serves several additional purposes. Its usage facilitates neutron time-focusing, eliminates the need for stringent magnetic shielding, and allows for compact setups. The scheme is robust, simple, and flexible. We believe that, with further improvements, it has the potential of adding inelastic signal discrimination capabilities to many existing diffraction instruments in the future.

  16. Understanding Magnetic Resonance Imaging of Knee Cartilage Repair: A Focus on Clinical Relevance.

    Science.gov (United States)

    Hayashi, Daichi; Li, Xinning; Murakami, Akira M; Roemer, Frank W; Trattnig, Siegfried; Guermazi, Ali

    2017-06-01

    The aims of this review article are (a) to describe the principles of morphologic and compositional magnetic resonance imaging (MRI) techniques relevant for the imaging of knee cartilage repair surgery and their application to longitudinal studies and (b) to illustrate the clinical relevance of pre- and postsurgical MRI with correlation to intraoperative images. First, MRI sequences that can be applied for imaging of cartilage repair tissue in the knee are described, focusing on comparison of 2D and 3D fast spin echo and gradient recalled echo sequences. Imaging features of cartilage repair tissue are then discussed, including conventional (morphologic) MRI and compositional MRI techniques. More specifically, imaging techniques for specific cartilage repair surgery techniques as described above, as well as MRI-based semiquantitative scoring systems for the knee cartilage repair tissue-MR Observation of Cartilage Repair Tissue and Cartilage Repair OA Knee Score-are explained. Then, currently available surgical techniques are reviewed, including marrow stimulation, osteochondral autograft, osteochondral allograft, particulate cartilage allograft, autologous chondrocyte implantation, and others. Finally, ongoing research efforts and future direction of cartilage repair tissue imaging are discussed.

  17. Asset management guide : focusing on the management of our transit investments.

    Science.gov (United States)

    2012-10-01

    To advance transit asset management, this guide provides a transit-specific asset management framework for managing assets indi-vidually and as a portfolio of assets that comprise an integrated system. The guide provides flexible, yet targeted guidan...

  18. MR-guided focused ultrasound: enhancement of intratumoral uptake of [3H]-docetaxel in vivo

    Science.gov (United States)

    Chen, Lili; Mu, Zhaomei; Hachem, Paul; Ma, C.-M.; Wallentine, Annie; Pollack, Alan

    2010-12-01

    The purpose of this study is to quantify the enhancement of [3H]-docetaxel in implanted prostate tumors treated with MR-guided pulsed focused ultrasound (MRgFUS). Human prostate cancer, LNCaP cells in 25 µl, were implanted into the prostates of male nude mice. The tumor growth was directly monitored on MRI. When the tumor reached a designated size, MRgFUS treatment was performed using a focused ultrasound treatment system (InSightec ExAblate 2000) with a 1.5 T GE MR scanner. The tumor-bearing animals were randomly divided into three groups: group 1, MRgFUS treatment + [3H]-docetaxel; group 2, [3H]-docetaxel only and group 3, as a control. Animals in group 1 were treated with MRgFUS non-invasively. Immediately after the treatment, the animals received a single dose of tail vein injection of docetaxel at 15 mg kg-1 mixed with [3H]-docetaxel at 50 uCi kg-1 in a total volume of 150 µl. Animals in group 2 were treated the same as in group one, however without MRgFUS treatment. Animals in group 3 were treated as a control. Animals were sacrificed 30 min after i.v. injections regardless of whether or not they received focused ultrasound. Tumors were removed and processed. The radioactivity of [3H]-docetaxel in the tumor tissue was quantitatively measured by a liquid scintillation counter. Our study showed that all animals tolerated the MRgFUS treatment well. Our data showed increased 3H-docetaxel concentration in the tumor in the MRgFUS-treated group (1079 ± 132 cmp/75 mg) versus those without MRgFUS treatment (524 ± 201 cmp/75 mg) with P = 0.037.

  19. An integrated ultrasound-guided high intensity focused ultrasound system for in-vivo experiment

    Science.gov (United States)

    Liu, Dalong; Ebbini, Emad S.

    2017-03-01

    We present the system architecture of an integrated Ultrasound-guided High Intensity Focused Ultrasound (USgHIFU) system for image-guided surgery and temperature tracking in vivo. The system is capable of operating with multiple frontends. Current implementation has a SonixRP for imaging and a custom designed dual mode ultrasound array (DMUA) system (32Tx/32Rx) for imaging/therapy. The highlights of the system include a fully-programmable, multiple data stream capable data processing engine, and an arbitrarily programmable high power array driver that is able to synthesize complex beam patterns in space and time. The data processing engine features a pipeline-style design that can be programmed on-the-fly by re-arranging the pre-verified GPU-accelerated high performance pipeline blocks, which cover an extensive range from basic functions such as filtering to specialized processing like speckle tracking. Furthermore, the pipeline design also has the option of bringing in MATLAB (Mathworks, Natick, MA, US) as part of the processing chain, thus vastly increase the capability of the system. By properly balancing the processing load between GPU-enabled routine and MATLAB script. This allows one to achieve a high degree of flexibility while meeting real-time constraints. Results are presented from in vivo rat experiment. Where low dose of therapeutic ultrasound was delivered into the hind limb of the Copenhagen rats using DMUA and temperature was tracked using a linear probe (HST, Ultrasonix). The data is processed in realtime with MATLAB in the loop to perform temperature regularization. Results show that we can reliably track the low temperature heating in the presence of motion artifacts (respiration and pulsation).

  20. Ethics Guide Recommendations for Organ-Donation-Focused Physicians: Endorsed by the Canadian Medical Association.

    Science.gov (United States)

    Shemie, Sam D; Simpson, Christy; Blackmer, Jeff; MacDonald, Shavaun; Dhanani, Sonny; Torrance, Sylvia; Byrne, Paul

    2017-05-01

    Donation physicians are specialists with expertise in organ and tissue donation and have been recognized internationally as a key contributor to improving organ and tissue donation services. Subsequent to a 2011 Canadian Critical Care Society-Canadian Blood Services consultation, the donation physician role has been gradually implemented in Canada. These professionals are generally intensive care unit physicians with an enhanced focus and expertise in organ/tissue donation. They must manage the dual obligation of caring for dying patients and their families while providing and/or improving organ donation services. In anticipation of actual, potential or perceived ethical challenges with the role, Canadian Blood Services in partnership with the Canadian Medical Association organized the development of an evidence-informed consensus process of donation experts and bioethicists to produce an ethics guide. This guide includes overarching principles and benefits of the DP role, and recommendations in regard to communication with families, role disclosure, consent discussions, interprofessional conflicts, conscientious objection, death determination, donation specific clinical practices in neurological determination of death and donation after circulatory death, end-of-life care, performance metrics, resources and remuneration. Although this report is intended to inform donation physician practices, it is recognized that the recommendations may have applicability to other professionals (eg, physicians in intensive care, emergency medicine, neurology, neurosurgery, pulmonology) who may also participate in the end-of-life care of potential donors in various clinical settings. It is hoped that this guidance will assist practitioners and their sponsoring organizations in preserving their duty of care, protecting the interests of dying patients, and fulfilling best practices for organ and tissue donation.

  1. Simulation of resonance focusing of light by dielectric cylinder with a square section

    Science.gov (United States)

    Kozlova, Elena S.; Kozlov, Dmitry A.; Kotlyar, Victor V.

    2017-04-01

    In this paper, a research on conditions for resonance excitation in a homogeneous dielectric cylinder with square crosssection is conducted using a FDTD-method. It is shown that in a cylinder with square cross-section resonant modes similar to whispering gallery modes can be excited, which helps in reducing the transverse dimensions of the focal spot. FDTD-method demonstrates an acceptable accuracy of the resonant mode detection.

  2. Feasibility of intermittent pneumatic compression for venous thromboembolism prophylaxis during magnetic resonance imaging-guided interventions

    Energy Technology Data Exchange (ETDEWEB)

    Maybody, Majid, E-mail: maybodym@mskcc.org [Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (United States); Taslakian, Bedros, E-mail: bt05@aub.edu.lb [Department of Diagnostic Radiology, American University of Beirut Medical Center, Riad El-Solh, 1107 2020 Beirut (Lebanon); Durack, Jeremy C., E-mail: durackj@mskcc.org [Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (United States); Kaye, Elena A., E-mail: kayee@mskcc.org [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (United States); Erinjeri, Joseph P., E-mail: erinjerj@mskcc.org [Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (United States); Srimathveeravalli, Govindarajan, E-mail: srimaths@mskcc.org [Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (United States); Solomon, Stephen B., E-mail: solomons@mskcc.org [Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (United States)

    2015-04-15

    Highlights: •The controller of a standard SCD is labeled as an “MR-unsafe”. •No commercially available “MR-safe” SCDs. •Standard SCDs can be used in iMRI by placing the device outside the MRI scanner room. •Using serial extension tubing did not cause device failure. -- Abstract: Purpose: Venous thromboembolism (VTE) is a common cause of morbidity and mortality in hospitalized and surgical patients. To reduce risk, perioperative VTE prophylaxis is recommended for cancer patients undergoing surgical or interventional procedures. Magnetic resonance imaging (MRI) is increasingly used in interventional oncology when alternative imaging modalities do not adequately delineate malignancies. Extended periods of immobilization during MRI-guided interventions necessitate an MR compatible sequential compression device (SCD) for intra-procedural mechanical VTE prophylaxis. Such devices are not commercially available. Materials and methods: A standard SCD routinely used at our institution for VTE prophylaxis during interventional procedures was used. To satisfy MR safety requirements, the SCD controller was placed in the MR control room and connected to the compression sleeves in the magnet room through the wave guide using tubing extensions. The controller pressure sensor was used to monitor adequate pressure delivery and detect ineffective low or abnormal high pressure delivery. VTE prophylaxis was provided using the above mentioned device for 38 patients undergoing MR-guided ablations. Results: There was no evidence of device failure due to loss of pressure in the extension tubing assembly. No interference with the anesthesia or interventional procedures was documented. Conclusion: Although the controller of a standard SCD is labeled as “MR-unsafe”, the SCD can be used in interventional MR settings by placing the device outside the MR scanner room. Using serial tubing extensions did not cause device failure. The described method can be used to provide

  3. Magnetic resonance imaging - guided vacuum-assisted breast biopsy: an initial experience in a community hospital

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, P.; Enis, S.; Pinyard, J., E-mail: jpinyard@gmail.com [Morristown Memorial Hospital, The Carol W. and Julius A. Rippel Breast Center, The Carol G. Simon Cancer Centre, Morristown, New Jersey (United States)

    2009-10-15

    To evaluate the effectiveness in diagnosing mammographically and sonographically occult breast lesions by using magnetic resonance imaging (MRI) guided vacuum-assisted breast biopsy in patients who presented to a community-based hospital with a newly established breast MRI program. The records of 142 consecutive patients, median age of 55 years, who had undergone MRI-guided biopsy at our institution between July 2006 and July 2007 were reviewed. From these patients, 197 mammographically and sonographically occult lesions were biopsied at the time of discovery. The pathology was then reviewed and correlated with the MRI findings. Cancer was present and subsequently discovered in 8% of the previously occult lesions (16/197) or 11% of the women studied (16/142). Of the cancerous lesions, 56% were invasive carcinomas (9/16) and 44% were ductal carcinomas in situ (7/16). Fourteen percent of the discovered lesions (28/197) were defined as high risk and included atypical ductal hyperplasia, atypical lobular hyperplasia, lobular carcinoma in situ, and radial scar. In total, occult cancerous and high-risk lesions were discovered in 22% of the found lesions (44/197) or 31% of the women who underwent MRI-guided biopsy (44/142). This study demonstrated that detection of cancerous and high-risk lesions can be significantly increased when an MRI-guided biopsy program is introduced at a community-based hospital. We believe that as radiologists gain confidence in imaging and histologic correlation, community-based hospitals can achieve similar rates of occult lesion diagnosis as those found in data emerging from academic institutions. (author)

  4. Combined microfiber knot resonator and focused ion beam-milled Mach-Zehnder interferometer for refractive index measurement

    Science.gov (United States)

    Gomes, André D.; André, Ricardo M.; Warren-Smith, Stephen C.; Dellith, Jan; Becker, Martin; Rothhardt, Manfred; Frazão, Orlando

    2017-04-01

    A Mach-Zehnder interferometer was created from a cavity milled in the taper region next to a microfiber knot resonator. A focused ion beam was used to mill the cavity with 47.8 μm in length. The microfiber knot resonator was created from an 11 μm diameter taper, produced using a filament fusion splicer. After milling the cavity, the microfiber knot resonator spectrum is still visible. The final response of the presented sensor is a microfiber knot resonator spectrum modulated by the Mach-Zehnder interference spectrum. A preliminary result of -8935 ± 108 nm/RIU was obtained for the refractive index sensitivity of the cavity component in a refractive index range of n = 1.333 to 1.341. Simultaneous measurement of refractive index and temperature using this combined structure is a future goal.

  5. Midterm Results after Uterine Artery Embolization Versus MR-Guided High-Intensity Focused Ultrasound Treatment for Symptomatic Uterine Fibroids

    Energy Technology Data Exchange (ETDEWEB)

    Froeling, V., E-mail: vera.froeling@charite.de; Meckelburg, K., E-mail: katrin.meckelburg@charite.de; Scheurig-Muenkler, C., E-mail: christian.scheurig-muenkler@charite.de; Schreiter, N. F., E-mail: nils.schreiter@charite.de; Kamp, J., E-mail: julia.kamp@charite.de; Maurer, M. H., E-mail: martin.maurer@charite.de; Beck, A., E-mail: alexander.beck@charite.de; Hamm, B., E-mail: bernd.hamm@charite.de; Kroencke, T. J., E-mail: Thomas.kroencke@charite.de [Charite-Universitaetsmedizin Berlin, Department of Radiology (Germany)

    2013-12-15

    Purpose: To compare the rate of reintervention and midterm changes in symptom severity (SS) and Total health-related quality of life (HRQoL) scores after uterine artery embolization (UAE) and magnetic resonance-guided high-intensity focused ultrasound (MR-g HIFU) for symptomatic uterine fibroids. Methods: Eighty women (median age 38.3 years), equally eligible for MR-g HIFU and UAE who underwent one of both treatments between 2002 and 2009 at our institution, were included. The primary end point of the study was defined as the rate of reintervention after both therapies. The secondary outcome was defined as changes in SS and Total HRQoL scores after treatment. SS and Total HRQoL scores before treatment and at midterm follow-up (median 13.3 months) were assessed by the uterine fibroid symptom and quality-of-life questionnaire (UFS-QoL) and compared. Results: The rate of reintervention was significantly lower after UAE than after MR-g HIFU (p = 0.002). After both treatments, SS and Total HRQoL scores improved significantly from baseline to follow-up (UAE: p < 0.001, p < 0.001; MR-g HIFU: p = 0.002, p < 0.001). Total HRQoL scores were significantly higher after UAE than after MR-g HIFU (p = 0.032). Changes in the SS scores did not differ significantly for both treatments (p = 0.061). Conclusion: UAE and MR-g HIFU significantly improved the health-related quality of life of women with symptomatic uterine fibroids. After UAE, the change in Total HRQoL score improvement was significantly better, and a significantly lower rate of reintervention was observed.

  6. Feasibility of ultrasound-guided high intensity focused ultrasound ablating uterine fibroids with hyperintense on T2-weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Wen-Peng, E-mail: zwp215@163.com [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Chen, Jin-Yun, E-mail: chenjinyun2006@126.com [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Zhang, Lian, E-mail: zhangl@haifu.com.cn [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Clinical Center for Tumor Therapy of 2nd Affiliated Hospital of Chongqing Medical University, 74 Linjiang Road, Chongqing 400010 (China); Li, Quan, E-mail: 1013283493@qq.com [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); Qin, Juan, E-mail: ant000999@163.com [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016 (China); and others

    2013-01-15

    Purpose: To retrospectively investigate whether uterine fibroids with hyperintense on pretreatment T2-weighted magnetic resonance imaging (MRI) could be treated with ultrasound-guided high intensity focused ultrasound (USgHIFU). Materials and methods: 282 patients with 282 symptomatic uterine fibroids who underwent USgHIFU treatment were retrospectively analyzed. Based on the signal intensity of T2-weighted MRI, uterine fibroids were classified as hypointense, isointense and hyperintense. Hyperintense fibroids were subjectively further subdivided into heterogeneous hyperintense, slightly homogeneous hyperintense and markedly homogeneous hyperintense based on the signal intensity of fibroid relative to myometrium and endometrium on T2-weighted MRI. Enhanced MRI was performed within one month after HIFU treatment. Non-perfused volume (NPV, indicative of successful ablation) ratio, treatment time, treatment efficiency, energy effect ratio and adverse events were recorded. Results: The median volume of uterine fibroids was 70.3 cm{sup 3} (interquartile range, 41.1–132.5 cm{sup 3}). The average NPV ratio, defined as non-perfused volume divided by the fibroid volume after HIFU treatment, was 76.8 ± 19.0% (range, 0–100%) in the 282 patients. It was 86.3 ± 11.9% (range, 40.9–100.0%) in the group with hypointense fibroids, 77.1 ± 16.5% (range, 32.2–100.0%) in isointense fibroids, and 67.6 ± 23.9% (range, 0–100.0%) in hyperintense fibroids. The lowest NPV ratio, lowest treatment efficiency, more treatment time, more sonication energy and pain scores were observed in the slightly homogeneous hyperintense fibroids, and the NPV ratio was 55.8 ± 26.7% (range, 0–83.9%) in this subgroup. Conclusion: Based on our results, the heterogeneous and markedly homogeneous hyperintense fibroids were suitable for USgHIFU, and only the slightly homogeneous hyperintense fibroids should be excluded.

  7. Ultrasound guided high intensity focused ultrasound (USgHIFU) ablation for uterine fibroids: Do we need the microbubbles?

    Science.gov (United States)

    Orsi, Franco; Monfardini, Lorenzo; Bonomo, Guido; Krokidis, Miltiadis; Della Vigna, Paolo; Disalvatore, Davide

    2015-05-01

    The aim of this study was to assess the safety and effectiveness of contrast-enhanced ultrasound (CEUS) on ultrasound guided high intensity focused ultrasound (USgHIFU) ablation of uterine fibroids. Thirty-three patients (37 fibroids) were randomly assigned to two groups: group A (17 patients, 20 fibroids) in which CEUS was used before, during and after HIFU treatment, and group B (16 patients, 17 fibroids) in which CEUS was not administered at all. Follow-up including contrast-enhanced magnetic resonance imaging (MRI) and a clinical questionnaire was performed, and technical success, ablation efficacy, volume reduction and complications were assessed. Technical success was 100% in both groups. CEUS revealed residual enhancement in 40% of the patients in group A and the treatment was continued until the completion of ablation. MRI at 1 month after treatment revealed significant difference in the relative fibroid volume reduction rate between the two groups: 16.1% in group A versus 4.8%, in group B (p = 0.01). There was no statistically significant relative volume reduction rate for the results at 3, 6 and 12 months and no significant changes in the quality of life results or the complication rate. CEUS was safe and effective in enhancing US guidance during HIFU ablation of uterine fibroids. Moreover, the use of CEUS during HIFU sonication increased the ablation efficacy, leading to a more relevant fibroid volume reduction at 1 and 3 months. This gap disappeared after 6 months, when there were no differences between the two groups of patients at MRI. However, in our experience, USgHIFU represented a very effective method for the treatment of uterine fibroids, and the use of CEUS during HIFU procedure reduced the treatment time and treatment repetitions for incomplete fibroid ablation.

  8. Using landscape ecology to focus ecological risk assessment and guide risk management decision-making.

    Science.gov (United States)

    Kapustka, L A; Galbraith, H; Luxon, B M; Yocum, J

    2001-06-01

    Ecological risk assessment (EcoRA) generally suffers from limited application of ecological knowledge in the definition and characterization of real-world sites. Not surprisingly, most remediation decisions, which follow, have little or no relationship to the valued ecological resources of the site or the broader region. The practice has evolved to favor engineering-based mitigation strategies, which eliminate excess chemical concentrations at sites, or otherwise break exposure pathways, but which may not be ecologically beneficial. The heavy emphasis of EcoRA on toxicity threshold levels tends to focus dollars on clean up of small areas or volumes with high concentrations. Moreover, intrusive remediation technologies often render an area uninhabitable to the very species that were to be protected. Infusion of ecological knowledge into EcoRA has been difficult. Most professional ecologists choose not to venture into the messy applied fields, leaving their impressive knowledge untapped. Moreover, narrowly defined responsibilities within government circles can limit cooperation and coordination. The realization that land use activities often have greater adverse consequences to wildlife than do chemicals provides an opportunity to change attitudes and practices. We are developing procedures that incorporate landscape features into the environmental management process. Specifically, we are using an iterative approach to: a) identify scenarios where habitat value is important in EcoRAs; b) guide selection of appropriate assessment species, i) keyed to wildlife distribution ranges; ii) keyed to a database of habitat suitability models; iii) cross-linked with the EPA exposure handbook species; iv) referenced to wildlife distributions (e.g., breeding bird survey); c) define data collection needs for reconnaissance-, screening-, and definitive-level characterization of habitat quality for potential assessment species; d) generate spatially explicit descriptions of habitat

  9. Magnetic resonance imaging assessment of effective ablated volume following high intensity focused ultrasound.

    Directory of Open Access Journals (Sweden)

    Brett Z Fite

    Full Text Available Under magnetic resonance (MR guidance, high intensity focused ultrasound (HIFU is capable of precise and accurate delivery of thermal dose to tissues. Given the excellent soft tissue imaging capabilities of MRI, but the lack of data on the correlation of MRI findings to histology following HIFU, we sought to examine tumor response to HIFU ablation to determine whether there was a correlation between histological findings and common MR imaging protocols in the assessment of the extent of thermal damage. Female FVB mice (n = 34, bearing bilateral neu deletion tumors, were unilaterally insonated under MR guidance, with the contralateral tumor as a control. Between one and five spots (focal size 0.5 × 0.5 × 2.5 mm3 were insonated per tumor with each spot receiving approximately 74.2 J of acoustic energy over a period of 7 seconds. Animals were then imaged on a 7T MR scanner with several protocols. T1 weighted images (with and without gadolinium contrast were collected in addition to a series of T2 weighted and diffusion weighted images (for later reconstruction into T2 and apparent diffusion coefficient maps, immediately following ablation and at 6, 24, and 48 hours post treatment. Animals were sacrificed at each time point and both insonated/treated and contralateral tumors removed and stained for NADH-diaphorase, caspase 3, or with hematoxylin and eosin (H&E. We found the area of non-enhancement on contrast enhanced T1 weighted imaging immediately post ablation correlated with the region of tissue receiving a thermal dose CEM43 ≥ 240 min. Moreover, while both tumor T2 and apparent diffusion coefficient values changed from pre-ablation values, contrast enhanced T1 weighted images appeared to be more senstive to changes in tissue viability following HIFU ablation.

  10. Magnetic resonance imaging assessment of effective ablated volume following high intensity focused ultrasound.

    Science.gov (United States)

    Fite, Brett Z; Wong, Andrew; Liu, Yu; Mahakian, Lisa M; Tam, Sarah M; Aina, Olulanu; Hubbard, Neil E; Borowsky, Alexander; Cardiff, Robert D; Dumont, Erik; Ferrara, Katherine W

    2015-01-01

    Under magnetic resonance (MR) guidance, high intensity focused ultrasound (HIFU) is capable of precise and accurate delivery of thermal dose to tissues. Given the excellent soft tissue imaging capabilities of MRI, but the lack of data on the correlation of MRI findings to histology following HIFU, we sought to examine tumor response to HIFU ablation to determine whether there was a correlation between histological findings and common MR imaging protocols in the assessment of the extent of thermal damage. Female FVB mice (n = 34), bearing bilateral neu deletion tumors, were unilaterally insonated under MR guidance, with the contralateral tumor as a control. Between one and five spots (focal size 0.5 × 0.5 × 2.5 mm3) were insonated per tumor with each spot receiving approximately 74.2 J of acoustic energy over a period of 7 seconds. Animals were then imaged on a 7T MR scanner with several protocols. T1 weighted images (with and without gadolinium contrast) were collected in addition to a series of T2 weighted and diffusion weighted images (for later reconstruction into T2 and apparent diffusion coefficient maps), immediately following ablation and at 6, 24, and 48 hours post treatment. Animals were sacrificed at each time point and both insonated/treated and contralateral tumors removed and stained for NADH-diaphorase, caspase 3, or with hematoxylin and eosin (H&E). We found the area of non-enhancement on contrast enhanced T1 weighted imaging immediately post ablation correlated with the region of tissue receiving a thermal dose CEM43 ≥ 240 min. Moreover, while both tumor T2 and apparent diffusion coefficient values changed from pre-ablation values, contrast enhanced T1 weighted images appeared to be more senstive to changes in tissue viability following HIFU ablation.

  11. Extracorporeal Ultrasound-Guided High Intensity Focused Ultrasound: Implications from the Present Clinical Trials

    Directory of Open Access Journals (Sweden)

    Tinghe Yu

    2014-01-01

    Full Text Available Extracorporeal ultrasound-guided high intensity focused ultrasound (HIFU has been clinically used for 15 years, and over 36000 cases have been reported. However, there yet lacked a consensus in the clinical values, suggesting the necessity of checking clinical findings. Clinical trials were searched and data reevaluated. HIFU was hardly performed alone; almost all present anticancer means have been applied during an HIFU treatment, and a specific regimen varied between trials; there were heterogeneity and disagreement between trials. The complexity made it difficult to distinguish the effect of HIFU. Based upon evaluable data, the efficacy of HIFU was similar to that of radio frequency, chemoembolization, chemotherapy, radiotherapy, or hormone therapy; a combined therapy did not improve the efficacy. The survival rate of HIFU plus radiotherapy was lower than that of radical surgery in liver cancers. Adverse events had no downtrend in the past years. HIFU was not a standardized procedure where the intensity and insonation mode were modified constantly throughout a treatment, limiting an evaluation from the perspective of ultrasonics. These implied that HIFU should be applied as an alternative at most occasions. The present clinical trials had defects making against the understating of HIFU.

  12. Image-Guided High Intensity Focused Ultrasound System for Large Animal Nerve Ablation Studies.

    Science.gov (United States)

    Worthington, Arthur; Peng, Philip; Rod, Kevin; Bril, Vera; Tavakkoli, Jahan

    2016-01-01

    High intensity focused ultrasound (HIFU) is a form of thermal ablation technique, which can treat a variety of medical afflictions. One promising therapeutic use is the permanent destruction of nerves non-invasively in patients with severe spasticity or certain types of pain (e.g., phantom limb pain). To this end, HIFU requires ultrasound guidance, which allows the non-invasive, target-specific deposition of thermal energy to the targeted nerve, thereby blocking axonal conduction. In this paper, a composite system comprising both ultrasound-imaging and HIFU therapy was developed and used to induce localized non-invasive nerve blockage in an in vivo large animal study. Five pigs were used with the femoral nerve as the target. Calibrated needle thermocouples inserted at the target site were employed to monitor the target tissue temperature. The degree of nerve blockage was assessed by measuring compound action potential (CAP) signal with a clinical nerve electrophysiology system before and after HIFU exposures. An average CAP signal amplitude reduction of 49% of baseline with a standard deviation of 9% was observed after 20-30 min post exposure. These results demonstrate the feasibility of the proposed ultrasound-guided HIFU modality as a potential non-invasive nerve ablation method.

  13. MRI-guided focused ultrasound thalamotomy in non-ET tremor syndromes.

    Science.gov (United States)

    Fasano, Alfonso; Llinas, Maheleth; Munhoz, Renato P; Hlasny, Eugen; Kucharczyk, Walter; Lozano, Andres M

    2017-08-22

    To report the 6-month single-blinded results of unilateral thalamotomy with MRI-guided focused ultrasound (MRgFUS) in patients with tremors other than essential tremor. Three patients with tremor due to Parkinson disease, 2 with dystonic tremor in the context of cervicobrachial dystonia and writer's cramp, and 1 with dystonia gene-associated tremor underwent MRgFUS targeting the ventro-intermedius nucleus (Vim) of the dominant hemisphere. The primary endpoint was the reduction of lateralized items of the Tremor Rating Scale of contralateral hemibody assessed by a blinded rater. All patients achieved a statistically significant, immediate, and sustained improvement of the contralateral tremor score by 42.2%, 52.0%, 55.9%, and 52.9% at 1 week and 1, 3, and 6 months after the procedure, respectively. All patients experienced transient side effects and 2 patients experienced persistent side effects at the time of last evaluation: hemitongue numbness and hemiparesis with hemihypoesthesia. Vim MRgFUS is a promising, incision-free, but nevertheless invasive technique to effectively treat tremors other than essential tremor. Future studies on larger samples and longer follow-up will further define its effectiveness and safety. NCT02252380. This study provides Class IV evidence that for patients with tremor not caused by essential tremor, MRgFUS of the Vim improves the tremor of the contralateral hemibody at 6 months. © 2017 American Academy of Neurology.

  14. Does the phase of menstrual cycle affect MR-guided focused ultrasound surgery of uterine leiomyomas?

    Energy Technology Data Exchange (ETDEWEB)

    So, Minna J. [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); Fennessy, Fiona M. [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); Zou, Kelly H. [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); McDannold, Nathan [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); Hynynen, Kullervo [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); Jolesz, Ferenc A. [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); Stewart, Elizabeth A. [Department of Obstetrics and Gynecology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); Rybicki, Frank J. [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States); Tempany, Clare M. [Department of Radiology, Brigham and Women' s Hospital/Harvard Medical School, Boston, MA (United States)]. E-mail: ctempanyafdhal@partners.org

    2006-08-15

    Purpose: To determine whether the phase of menstrual cycle at the time of MR-guided focused ultrasound surgery (MRgFUS) treatment for uterine leiomyomas affects treatment outcome. Methods: We enrolled all patients participating in a prospective phase III clinical trial from our center who completed 6 months of clinical and imaging follow-up. Patients with irregular cycles and those on oral contraceptives were excluded. Data prospectively documenting the date of the last menstrual period (LMP) at the time of treatment, length and duration of cycle, and raw symptom severity score (SSS) from the Uterine Fibroid Symptom and Quality of Life questionnaire, at baseline and 6 months were collected. Proliferative phase patients were determined retrospectively as those who were treated within less than 14 days from LMP; secretory phase patients were classified as those who were treated greater than 14 days from LMP. Results: A total of 58 patients were enrolled. There was no significant difference in the mean SSS at baseline and mean SSS at 6 months between patients treated in the proliferative versus secretory phase of the cycle. No significant difference in the SSS change from baseline to 6 months was seen between the two groups. Conclusions: Menstrual cycle phase does not influence MRgFUS treatment outcome. Symptomatic improvement occurs with treatment during either phase of the menstrual cycle. Thus, the scheduling of MRgFUS treatment need not be based upon the phase of the menstrual cycle.

  15. MRI Guided Focused Ultrasound Thalamotomy for Moderate-to-Severe Tremor in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Ilana Schlesinger

    2015-01-01

    Full Text Available Background. Thalamotomy is effective in alleviating tremor in Parkinson’s disease (PD. Methods. Seven PD patients, mean age 59.4 ± 9.8 years (range, 46–74 with a mean disease duration of 5.4 ± 2.8 years (range, 2–10 suffering from severe refractory tremor, underwent ventral intermediate nucleus thalamotomy using MRI guided focused ultrasound (MRgFUS, an innovative technology that enables noninvasive surgery. Results. Tremor stopped in the contralateral upper extremity in all patients immediately following treatment. Total UPDRS decreased from 37.4 ± 12.2 to 18.8 ± 11.1 (p=0.007 and PDQ-39 decreased from 42.3 ± 16.4 to 21.6 ± 10.8 (p=0.008 following MRgFUS. These effects were sustained (mean follow-up 7.3 months. Adverse events during MRgFUS included headache (n=3, dizziness (n=2, vertigo (n=4, and lip paresthesia (n=1 and following MRgFUS were hypogeusia (n=1, unsteady feeling when walking (n=1, resolved, and disturbance when walking tandem (n=1, resolved. Conclusions. Thalamotomy using MRgFUS is safe and effective in PD patients. Large randomized studies are needed to assess prolonged efficacy and safety.

  16. Site-Specific Cryo-focused Ion Beam Sample Preparation Guided by 3D Correlative Microscopy.

    Science.gov (United States)

    Arnold, Jan; Mahamid, Julia; Lucic, Vladan; de Marco, Alex; Fernandez, Jose-Jesus; Laugks, Tim; Mayer, Tobias; Hyman, Anthony A; Baumeister, Wolfgang; Plitzko, Jürgen M

    2016-02-23

    The development of cryo-focused ion beam (cryo-FIB) for the thinning of frozen-hydrated biological specimens enabled cryo-electron tomography (cryo-ET) analysis in unperturbed cells and tissues. However, the volume represented within a typical FIB lamella constitutes a small fraction of the biological specimen. Retaining low-abundance and dynamic subcellular structures or macromolecular assemblies within such limited volumes requires precise targeting of the FIB milling process. In this study, we present the development of a cryo-stage allowing for spinning-disk confocal light microscopy at cryogenic temperatures and describe the incorporation of the new hardware into existing workflows for cellular sample preparation by cryo-FIB. Introduction of fiducial markers and subsequent computation of three-dimensional coordinate transformations provide correlation between light microscopy and scanning electron microscopy/FIB. The correlative approach is employed to guide the FIB milling process of vitrified cellular samples and to capture specific structures, namely fluorescently labeled lipid droplets, in lamellas that are 300 nm thick. The correlation procedure is then applied to localize the fluorescently labeled structures in the transmission electron microscopy image of the lamella. This approach can be employed to navigate the acquisition of cryo-ET data within FIB-lamellas at specific locations, unambiguously identified by fluorescence microscopy. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  17. Target detection: Magnetic resonance imaging-ultrasound fusion–guided prostate biopsy

    Science.gov (United States)

    Sonn, Geoffrey A.; Margolis, Daniel J.; Marks, Leonard S.

    2014-01-01

    Recent advances in multiparametric magnetic resonance imaging (MRI) have enabled image-guided detection of prostate cancer. Fusion of MRI with real-time ultrasound (US) allows the information from MRI to be used to direct biopsy needles under US guidance in an office-based procedure. Fusion can be performed either cognitively or electronically, using a fusion device. Fusion devices allow superimposition (coregistration) of stored MRI images on real-time US images; areas of suspicion found on MRI can then serve as targets during US-guided biopsy. Currently available fusion devices use a variety of technologies to perform coregistration: robotic tracking via a mechanical arm with built-in encoders (Artemis/Eigen, BioJet/Geoscan); electromagnetic tracking (UroNav/Philips-Invivo, Hi-RVS/Hitachi); or tracking with a 3D US probe (Urostation/Koelis). Targeted fusion biopsy has been shown to identify more clinically significant cancers and fewer insignificant cancers than conventional biopsy. Fusion biopsy appears to be a major advancement over conventional biopsy because it allows (1) direct targeting of suspicious areas not seen on US and (2) follow-up biopsy of specific cancerous sites in men undergoing active surveillance. PMID:24239473

  18. Engineered gadolinium-doped carbon dots for magnetic resonance imaging-guided radiotherapy of tumors.

    Science.gov (United States)

    Du, Fengyi; Zhang, Lirong; Zhang, Li; Zhang, Miaomiao; Gong, Aihua; Tan, Youwen; Miao, Jiawen; Gong, Yuhua; Sun, Mingzhong; Ju, Huixiang; Wu, Chaoyang; Zou, Shenqiang

    2017-03-01

    The effectiveness of radiotherapy can decrease due to inaccurate positioning of machinery and inherent radioresistance of tumors. To address this issue, we present a novel theranostic nanoplatform based on gadolinium-doped carbon dots (Gd-doped CDs) designed specifically for magnetic resonance imaging (MRI)-guided radiotherapy of tumors. The Gd-doped CDs (∼18 nm) with dispersibility in water and stable photoluminescence were synthesized via a one-step hydrothermal approach. After tail vein injection of the Gd-doped CDs, they exhibited a relatively long circulation time (∼6 h), enabled efficient passive tumor targeting. Gd-doped CDs accumulate in the kidney and could be cleared out of the body from bladder. Importantly, they exhibited favorable biocompatibility with excellent performance in longitudinal relaxivity rate (r1) of 6.45 mM(-1)S(-1) and radiosensitization enhancements. These results show that Gd-doped CDs are excellent T1 contrast agents and radiosensitizers, possessing great promise for MRI-guided radiotherapy of tumors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. A Passive Parallel Master-Slave Mechanism for Magnetic Resonance Imaging-Guided Interventions.

    Science.gov (United States)

    Elayaperumal, Santhi; Cutkosky, Mark R; Renaud, Pierre; Daniel, Bruce L

    2015-03-01

    A passive, parallel master-slave mechanism is presented for magnetic resonance imaging (MRI)-guided interventions in the pelvis. The mechanism allows a physician to stand outside the MRI scanner while manipulating a needle inside the bore and, unlike a powered robot, does not place actuators in proximity to the patient. The manipulator combines two parallel mechanisms based on the Delta robot architecture. The mechanism also includes a two-axis gimbal to allow for tool angulation, giving a total of five degrees of freedom so that the physician can insert and steer a needle using continuous natural arm and wrist movements, unlike simple needle guides. The need for access between the patient's legs and within the MRI scanner leads to an unusual asymmetric design in which the sliding prismatic joints form the vertices of an isosceles triangle. Kinematic analysis shows that the dexterity index of this design is improved over the desired workspace, as compared to an equilateral design. The analysis is extended to estimate the effect of friction and model the input:output force transmission. Prototypes, with final dimensions selected for transperineal prostate interventions, showed force transmission behavior as predicted by simulation, and easily withstood maximum forces required for tool insertion.

  20. Magnetic Resonance-Guided High Intensity Focused Ultrasound Ablation of Breast Cancer

    NARCIS (Netherlands)

    Knuttel, Floor; van den Bosch, Maurice A A J

    2016-01-01

    This chapter describes several aspects of MR-HIFU treatment for breast cancer. The current and future applications, technical developments and clinical results are discussed. MR-HIFU ablation is under investigation for the treatment of breast cancer, but is not yet ready for clinical implementation.

  1. A retrospective study of magnetic resonance-guided focused ultrasound ablation for uterine myoma in Taiwan

    Directory of Open Access Journals (Sweden)

    Sheng-Ling Tung

    2016-10-01

    Conclusion: The results obtained from this study demonstrated that MRgFUS can be safely and effectively used to ablate uterine fibroids to produce a significant decrease in mean fibroid volume and improve SSS for up to 6 months after treatment.

  2. Highly compliant guided-mode resonance nanogratings: From theory to application in mechanical strain sensing

    Science.gov (United States)

    Foland, Steven J.

    This work reports the theory, design, fabrication, and characterization of highly-compliant polymer-based guided-mode resonance (GMR) grating devices. GMR devices have been widely researched in recent years for their applications in telecommunications and biosensing. The vast majority of GMR-based sensors are fabricated and characterized on rigid transparent substrates, and are designed to respond to changes in the optical properties of their surrounding media. While useful in a number of conventional sensing configurations, the applications of rigid gratings for mechanical sensing are extremely limited. To enable a GMR sensor to respond to mechanical stimuli, both the grating and its substrate must be compliant, a property inherent to the devices presented herein. An extensive toolset is required for the design of such resonant optical devices; this dissertation defines the theoretical and simulations models used for the analysis of these dynamic grating devices, and provides a clear understanding of both their strengths and limitations. These tools include a waveguide-theory based theoretical model for rapid approximation of grating resonance conditions, and finite element method (FEM) simulation for full-field solutions to Maxwell's equations. A number of challenges which arise when attempting to fabricate nanostructures on a thin polymer are also addressed, and a fabrication process is developed to enable a practical embodiment of the proposed devices. The results of this process are subwavelength titanium dioxide (TiO2) gratings embedded at the surface of compliant polydimethylsiloxane (PDMS) structures. Both a one-dimensional, membrane-embedded GMR grating for local measurement of microfluidic channel pressure, and a two-dimensional, slab-embedded GMR grating for biaxial strain detection are discussed, demonstrated, and evaluated. Additionally, potential improvements to the devices' performance and suggestions for future work are provided.

  3. Clinical Outcome Following Low Suspicion Multiparametric Prostate Magnetic Resonance Imaging or Benign Magnetic Resonance Imaging Guided Biopsy to Detect Prostate Cancer.

    Science.gov (United States)

    Boesen, Lars; Nørgaard, Nis; Løgager, Vibeke; Thomsen, Henrik S

    2017-08-01

    We assessed the risk of significant prostate cancer being detected after low suspicion magnetic resonance imaging or suspicious magnetic resonance imaging with benign magnetic resonance imaging guided biopsies in men with prior negative systematic biopsies. Overall 289 prospectively enrolled men underwent magnetic resonance imaging followed by repeat systematic and targeted biopsies of any suspicious lesions at baseline. A total of 194 patients with low suspicion magnetic resonance imaging or benign target biopsies were suitable for this study. Those who were negative for prostate cancer at baseline were followed for at least 3 years. We calculated the negative predictive values of magnetic resonance imaging in ruling out any prostate cancer and significant prostate cancer, defined as any core with Gleason score greater than 6, or more than 2 positive cores/cancerous core 50% or greater. Prostate cancer was detected in 38 of 194 (20%) patients during the median study period of 47 months (IQR 43-52). The overall negative predictive value of magnetic resonance imaging in ruling out any and significant prostate cancer was 80% (156 of 194) and 95% (184 of 194), respectively. No patient with low suspicion magnetic resonance imaging had intermediate/high grade cancer (Gleason score greater than 6). The majority of patients with no cancer during followup (132 of 156, 85%) had a decreasing prostate specific antigen and could be monitored in primary care. Low suspicion magnetic resonance imaging in men with prior negative systematic biopsies has a high negative predictive value in ruling out longer term, significant cancer. Therefore, immediate repeat biopsies are of limited clinical value and could be avoided even if prostate specific antigen is persistently increased. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  4. Quantification of intraventricular blood clot in MR-guided focused ultrasound surgery

    Science.gov (United States)

    Hess, Maggie; Looi, Thomas; Lasso, Andras; Fichtinger, Gabor; Drake, James

    2015-03-01

    Intraventricular hemorrhage (IVH) affects nearly 15% of preterm infants. It can lead to ventricular dilation and cognitive impairment. To ablate IVH clots, MR-guided focused ultrasound surgery (MRgFUS) is investigated. This procedure requires accurate, fast and consistent quantification of ventricle and clot volumes. We developed a semi-autonomous segmentation (SAS) algorithm for measuring changes in the ventricle and clot volumes. Images are normalized, and then ventricle and clot masks are registered to the images. Voxels of the registered masks and voxels obtained by thresholding the normalized images are used as seed points for competitive region growing, which provides the final segmentation. The user selects the areas of interest for correspondence after thresholding and these selections are the final seeds for region growing. SAS was evaluated on an IVH porcine model. SAS was compared to ground truth manual segmentation (MS) for accuracy, efficiency, and consistency. Accuracy was determined by comparing clot and ventricle volumes produced by SAS and MS, and comparing contours by calculating 95% Hausdorff distances between the two labels. In Two-One-Sided Test, SAS and MS were found to be significantly equivalent (p < 0.01). SAS on average was found to be 15 times faster than MS (p < 0.01). Consistency was determined by repeated segmentation of the same image by both SAS and manual methods, SAS being significantly more consistent than MS (p < 0.05). SAS is a viable method to quantify the IVH clot and the lateral brain ventricles and it is serving in a large-scale porcine study of MRgFUS treatment of IVH clot lysis.

  5. MR-guided High Intensity Focused Ultrasound Treatment for Symptomatic Uterine Leiomyomata: Long-term Outcomes

    Science.gov (United States)

    Kim, Hyun S.; Baik, Jun-Hyun; Pham, Luu D.; Jacobs, Michael A

    2011-01-01

    PURPOSE To evaluate the long-term clinical outcomes of MR-guided high intensity focused ultrasound (MR-g HIFU) treatments for symptomatic uterine leiomyomata. MATERIAL AND METHODS Patients were recruited for a prospective study for MR-g HIFU treatments of symptomatic leiomyomata, with up to three-year follow-up. The study was approved by the institutional review board and was HIPPA compliant. Clinical assessments were obtained at 3 months, 6 months, 1, 2 and 3 years after MR-g HIFU, as well as uterine fibroid symptom severity scores (SSS) and health-related quality of life questionnaires (UFS-QOL). MRI was performed at each follow-up to assess the efficacy of the treatment at 6 months, 1 year, 2 years and 3 years. RESULTS Fifty one leiomyomata in 40 patients were treated. All patients were treated within the FDA guidelines with leiomyomata localized on MR and treated with sonication. The mean baseline volume of treated leiomyomata was 336.9 cm3. The mean improvement scores for tSSS was 47.8 (p<.001) and for tUFS-QOL was 39.8 (p<.001) at 3 years. The mean volume decrease in treated leiomyomata was 32.0% (p<.001), and, in uterus, the volume decrease was 27.7% (p<.001) at three years. There were no long-term complications. CONCLUSION Long-term follow-up data from MR-g HIFU treatments show sustained symptomatic relief among enrolled patients. Although the results are preliminary, MR-g HIFU for the treatment of uterine leiomyomata may result in acceptable long-term outcomes at three years. PMID:21718955

  6. Effective Teaching Strategies for Successful Inclusion: A Focus on Down Syndrome. A Resource Guide for Educators and Parents.

    Science.gov (United States)

    Tien, Barbara

    This guide focuses on methods to teach students with Down Syndrome to maximize their inclusion in school and the community. Following an introductory section, the 10 chapters provide information and practical guidelines on the following topics: (1) acknowledging the label but teaching the student; (2) medical facts about Down Syndrome (e.g.,…

  7. Ectopic pregnancy: pictorial essay focusing on computed tomography and magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Febronio, Eduardo Miguel; Rosas, George de Queiroz; D' Ippolito, Giuseppe [Escola Paulista de Medicina - Universidade Federal de Sao Paulo (EPM-Unifesp), Sao Paulo, SP (Brazil). Dept. of Imaging Diagnosis; Cardia, Patricia Prando, E-mail: giuseppe_dr@uol.com.br [Centro Radiologico Campinas, Campinas, SP (Brazil)

    2012-09-15

    The objective of the present study is to describe key computed tomography and magnetic resonance imaging findings in patients with acute abdominal pain caused by ectopic pregnancy. For this purpose, two radiologists consensually selected and analyzed computed tomography and magnetic resonance imaging studies performed in female patients with acute abdominal pain caused by proven ectopic pregnancy in the period between January 2010 and December 2011. The imaging diagnosis of ectopic pregnancy is usually obtained by ultrasonography, however, with the increasing use of computed tomography and magnetic resonance imaging in the assessment of patients with acute abdomen of gynecological origin it is necessary that the radiologist becomes familiar with the main findings observed at these diagnostic methods. (author)

  8. Acute pelvic inflammatory disease: pictorial essay focused on computed tomography and magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Febronio, Eduardo Miguel; Rosas, George de Queiroz; D' Ippolito, Giuseppe, E-mail: giuseppe_dr@uol.com.br [Department of Imaging Diagnosis, Escola Paulista de Medicina - Universidade Federal de Sao Paulo (EPMUnifesp), Sao Paulo, SP (Brazil)

    2012-11-15

    The present study was aimed at describing key computed tomography and magnetic resonance imaging findings in patients with acute abdominal pain derived from pelvic inflammatory disease. Two radiologists consensually selected and analyzed computed tomography and magnetic resonance imaging studies performed between January 2010 and December 2011 in patients with proven pelvic inflammatory disease leading to presentation of acute abdomen. Main findings included presence of intracavitary fluid collections, anomalous enhancement of the pelvic excavation and densification of adnexal fat planes. Pelvic inflammatory disease is one of the leading causes of abdominal pain in women of childbearing age and it has been increasingly been diagnosed by means of computed tomography and magnetic resonance imaging supplementing the role of ultrasonography. It is crucial that radiologists become familiar with the main sectional imaging findings in the diagnosis of this common cause of acute abdomen (author)

  9. Critical evaluation of magnetic resonance imaging targeted, transrectal ultrasound guided transperineal fusion biopsy for detection of prostate cancer.

    Science.gov (United States)

    Kuru, Timur H; Roethke, Matthias C; Seidenader, Jonas; Simpfendörfer, Tobias; Boxler, Silvan; Alammar, Khalid; Rieker, Philip; Popeneciu, Valentin I; Roth, Wilfried; Pahernik, Sascha; Schlemmer, Heinz-Peter; Hohenfellner, Markus; Hadaschik, Boris A

    2013-10-01

    Diagnosis and precise risk stratification of prostate cancer is essential for individualized treatment decisions. Magnetic resonance imaging/transrectal ultrasound fusion has shown encouraging results for detecting clinically significant prostate cancer. We critically evaluated magnetic resonance imaging targeted, transrectal ultrasound guided transperineal fusion biopsy in routine clinical practice. Included in this prospective study were 347 consecutive patients with findings suspicious for prostate cancer. Median age was 65 years (range 42 to 84) and mean prostate specific antigen was 9.85 ng/ml (range 0.5 to 104). Of the men 49% previously underwent transrectal ultrasound guided biopsies, which were negative, and 51% underwent primary biopsy. In all patients 3 Tesla multiparametric magnetic resonance imaging was done. Systematic stereotactic prostate biopsies plus magnetic resonance imaging targeted, transrectal ultrasound guided biopsies were performed in those with abnormalities on magnetic resonance imaging. Imaging data and biopsy results were analyzed. A self-designed questionnaire was sent to all men on further clinical history and biopsy adverse effects. Of 347 patients biopsy samples of 200 (58%) showed prostate cancer and 73.5% of biopsy proven prostate cancer were clinically relevant according to National Comprehensive Cancer Network (NCCN) criteria. On multiparametric magnetic resonance imaging 104 men had findings highly suspicious for prostate cancer. The tumor detection rate was 82.6% (86 of 104 men) with a Gleason score of 7 or greater in 72%. Overall targeted cores detected significantly more cancer than systematic biopsies (30% vs 8.2%). Of 94 patients without cancer suspicious lesions on magnetic resonance imaging 11 (11.7%) were diagnosed with intermediate risk disease. Regarding adverse effects, 152 of 300 patients (50.6%) reported mild hematuria, 26% had temporary erectile dysfunction and 2.6% needed short-term catheterization after biopsy

  10. Magnetic resonance imaging of the cardiac venous system and magnetic resonance-guided intubation of the coronary sinus in swine: a feasibility study.

    Science.gov (United States)

    Neizel, Mirja; Krämer, Nils; Schütte, Adrian; Schnackenburg, Bernhard; Krüger, Sascha; Kelm, Malte; Günther, Rolf W; Kühl, Harald P; Krombach, Gabriele A

    2010-08-01

    To visualize the coronary sinus using magnetic resonance (MR), and to demonstrate the feasibility of MR-guided intubation of the cardiac venous system (CVS) in swine. A total of 6 pigs were investigated. All experiments were performed using an interventional 1.5-Tesla MRI system. The CVS was visualized using an inversion-recovery navigator-gated whole-heart steady-state free-precession sequence after administration of gadobenate dimeglumine contrast agent. The coronary sinus was then intubated under MR-guidance with a passive MR-compatible guidewire modified by incorporation of iron oxide markers for improved visualization and a nonbraided Cobra-catheter. MR-guided interventions were monitored using a steady-state free-precession real-time imaging sequence. Time needed was measured for MR-guided intubation of the CVS and compared with the time needed for fluoroscopy guided intubation of the CVS. Visualization and intubation of the coronary sinus and its site branches was feasible in all cases. Time spent for MR-guided intubation of the CVS was comparable to time spent for fluoroscopy-guided intubation (8.2 +/- 2 minutes vs. 8.3 +/- 1.3 minutes; P = 0.85). MR-visualization and MR-guided intubation of the coronary sinus and its side branches is feasible. The feasibility of MR-guided intubation of the CVS might have relevance for procedures like cardiac resynchronization therapy and percutaneous transcatheter mitral annuloplasty, requiring improved 3-dimensional knowledge about cardiac vein anatomy in the near future.

  11. Three-Dimensional Dosimetric Validation of a Magnetic Resonance Guided Intensity Modulated Radiation Therapy System

    Energy Technology Data Exchange (ETDEWEB)

    Rankine, Leith J., E-mail: Leith_Rankine@med.unc.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Department of Radiation Oncology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Mein, Stewart [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Cai, Bin; Curcuru, Austen [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Juang, Titania; Miles, Devin [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Mutic, Sasa; Wang, Yuhe [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Oldham, Mark [Medical Physics Graduate Program, Duke University, Durham, North Carolina (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina (United States); Li, H. Harold, E-mail: hli@radonc.wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States)

    2017-04-01

    Purpose: To validate the dosimetric accuracy of a commercially available magnetic resonance guided intensity modulated radiation therapy (MRgIMRT) system using a hybrid approach: 3-dimensional (3D) measurements and Monte Carlo calculations. Methods and Materials: We used PRESAGE radiochromic plastic dosimeters with remote optical computed tomography readout to perform 3D high-resolution measurements, following a novel remote dosimetry protocol. We followed the intensity modulated radiation therapy commissioning recommendations of American Association of Physicists in Medicine Task Group 119, adapted to incorporate 3D data. Preliminary tests (“AP” and “3D-Bands”) were delivered to 9.5-cm usable diameter cylindrical PRESAGE dosimeters to validate the treatment planning system (TPS) for nonmodulated deliveries; assess the sensitivity, uniformity, and rotational symmetry of the PRESAGE dosimeters; and test the robustness of the remote dosimetry protocol. Following this, 4 clinical MRgIMRT plans (“MultiTarget,” “Prostate,” “Head/Neck,” and “C-Shape”) were measured using 13-cm usable diameter PRESAGE dosimeters. For all plans, 3D-γ (3% or 3 mm global, 10% threshold) passing rates were calculated and 3D-γ maps were examined. Point doses were measured with an IBA-CC01 ionization chamber for validation of absolute dose. Finally, by use of an in-house-developed, GPU-accelerated Monte Carlo algorithm (gPENELOPE), we independently calculated dose for all 6 Task Group 119 plans and compared against the TPS. Results: For PRESAGE measurements, 3D-γ analysis yielded passing rates of 98.7%, 99.2%, 98.5%, 98.0%, 99.2%, and 90.7% for AP, 3D-Bands, MultiTarget, Prostate, Head/Neck, and C-Shape, respectively. Ion chamber measurements were within an average of 0.5% (±1.1%) from the TPS dose. Monte Carlo calculations demonstrated good agreement with the TPS, with a mean 3D-γ passing rate of 98.5% ± 1.9% using a stricter 2%/2-mm criterion. Conclusions: We

  12. Theranostic porphyrin dyad nanoparticles for magnetic resonance imaging guided photodynamic therapy.

    Science.gov (United States)

    Liang, Xiaolong; Li, Xiaoda; Jing, Lijia; Yue, Xiuli; Dai, Zhifei

    2014-08-01

    Photodynamic therapy (PDT) is a site-specific treatment of cancer involving the administration of a photosensitizer (PS) followed by the local light activation. Besides efficient PSs, image guidance is essential for precise and safe light delivery to the targeting site, thus improving the therapeutic effectiveness. Herein, we report the fabrication of theranostic porphyrin dyad nanoparticles (TPD NPs) for magnetic resonance imaging (MRI)-guided PDT cancer therapy, where the inner metal free porphyrin functions as a photosensitizer for PDT while the outer Mn-porphyrin serve as an MRI contrast agent. Covalent attachment of porphyrins to TPD NPs avoids premature release during systemic circulation. In addition, TPD NPs (~60 nm) could passively accumulate in tumors and be avidly taken up by tumor cells. The PDT and MRI capabilities of TPD NPs can be conveniently modulated by varying the molar ratio of metal free porphyrin/Mn-porphyrin. At the optimal molar ratio of 40.1%, the total drug loading content is up to 49.8%, 31.3% for metal free porphyrin and 18.5% for Mn-porphyrin. The laser light ablated the tumor completely within 7 days in the presence of TPD NPs and the tumor growth inhibition was 100%. The relaxivities were determined to be 20.58 s(-1) mm(-1) for TPD NPs, about four times as much as that of Mn-porphyrin (5.16 s(-1) mm(-1)). After 24 h intravenous injection of TPD NPs, MRI images showed that the whole tumor area remained much brighter than surrounding healthy tissue, allowing to guide the laser light to the desired tumor site for photodynamic ablation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Seroma change during magnetic resonance imaging-guided partial breast irradiation and its clinical implications.

    Science.gov (United States)

    Jeon, Seung Hyuck; Shin, Kyung Hwan; Park, So-Yeon; Kim, Jung-In; Park, Jong Min; Kim, Jin Ho; Chie, Eui Kyu; Wu, Hong-Gyun

    2017-06-20

    To investigate the patterns of post-lumpectomy seroma volume (SV) change and related clinical factors to determine the benefits of adaptive planning in magnetic resonance imaging (MRI)-guided partial breast irradiation (PBI). MRI data obtained from 37 women with early breast cancer acquired at simulation and at the 1st, 6th, and 10th fractions were analyzed. The planning target volume (PTV) was defined as unequal margins of 10-15 mm added according to the directional surgical margin status of each seroma. Treatment was performed using a 0.35 T MRI-guided radiotherapy system. Univariate analysis was performed to assess the correlations between SV change rate and clinical factors. Seroma and PTV for adaptive planning were based on the images obtained at the 6th fraction. The average time intervals between surgery-simulation, simulation-1st, 1st-6th, and 6th-10th fractions were 23.1, 8.5, 7.2, and 5.9 days, respectively. Of the 37 patients, 33 exhibited decreased SV over the treatment period. The mean SV of these 33 patients decreased from 100% at simulation to 60, 48, and 40% at each MRI scan. In most cases (26/33), the logarithm of SV was inversely proportional to the elapsed time from surgery (R (2) > 0.90, Pearson's correlation test). The volume of spared normal tissue from adaptive radiotherapy was proportional to the absolute change in SV (R (2) = 0.89, Pearson's correlation test). Seromas exhibit exponential shrinkage over the course of PBI. In patients receiving PBI, frequent monitoring of SV could be helpful in decision-making regarding adaptive planning, especially those with a large seroma.

  14. Usefulness of cardiac magnetic resonance-guided management in patients with recurrent pericarditis.

    Science.gov (United States)

    Alraies, M Chadi; AlJaroudi, Wael; Yarmohammadi, Hirad; Yingchoncharoen, Teerapat; Schuster, Andres; Senapati, Alpana; Tariq, Muhammad; Kwon, Deborah; Griffin, Brian P; Klein, Allan L

    2015-02-15

    Recurrent pericarditis (RP) affects 10% to 50% of patients with acute pericarditis. The use of steroids has been associated with increased recurrence rate of pericarditis, along with known major side effects. Cardiac magnetic resonance imaging (CMR) is more frequently used to assess pericardial inflammation and less commonly to guide therapy. The aim of this study was to assess the utility of CMR in the management of RP compared with standard therapy. A total of 507 consecutive patients with RP after the first attack, all of whom were treated with colchicine and nonsteroidal anti-inflammatory drugs as first-line therapy, were retrospectively evaluated. There were 257 patients who were treated with medications and received CMR-guided therapy (group 1) and 250 patients who were treated with medications without CMR (group 2). The 2 groups had similar baseline characteristics and follow-up periods (17 ± 7.9 vs 16.3 ± 16.2 months, respectively, p = 0.97). CMR was used to assess the presence of pericardial inflammation, and on the basis of the results, the clinician made changes to the steroid dose dictated by the severity of inflammation. There was no significant difference in the incidence of constrictive pericarditis, pericardial window, or pericardiectomy between groups during the follow-up. However, group 2 patients had a larger number of steroid pulse therapies (defined as prednisone 50 mg/day orally for 10 days and tapering to none over 4 weeks), and higher overall total milligrams of steroid administered compared with the CMR group (p = 0.003 and p = 0.001, respectively). Recurrence and pericardiocentesis rates were lower in group 1 (p pericarditis recurrence and exposure to steroids. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Feasibility of real-time magnetic resonance imaging-guided endomyocardial biopsies: An in-vitro study.

    Science.gov (United States)

    Lossnitzer, Dirk; Seitz, Sebastian A; Krautz, Birgit; Schnackenburg, Bernhard; André, Florian; Korosoglou, Grigorios; Katus, Hugo A; Steen, Henning

    2015-07-26

    To investigate if magnetic resonance (MR)-guided biopsy can improve the performance and safety of such procedures. A novel MR-compatible bioptome was evaluated in a series of in-vitro experiments in a 1.5T magnetic resonance imaging (MRI) system. The bioptome was inserted into explanted porcine and bovine hearts under real-time MR-guidance employing a steady state free precession sequence. The artifact produced by the metal element at the tip and the signal voids caused by the bioptome were visually tracked for navigation and allowed its constant and precise localization. Cardiac structural elements and the target regions for the biopsy were clearly visible. Our method allowed a significantly better spatial visualization of the bioptoms tip compared to conventional X-ray guidance. The specific device design of the bioptome avoided inducible currents and therefore subsequent heating. The novel MR-compatible bioptome provided a superior cardiovascular magnetic resonance (imaging) soft-tissue visualization for MR-guided myocardial biopsies. Not at least the use of MRI guidance for endomyocardial biopsies completely avoided radiation exposure for both patients and interventionalists. MRI-guided endomyocardial biopsies provide a better than conventional X-ray guided navigation and could therefore improve the specificity and reproducibility of cardiac biopsies in future studies.

  16. Integrated ultrasound and magnetic resonance imaging for simultaneous temperature and cavitation monitoring during focused ultrasound therapies

    Science.gov (United States)

    Arvanitis, Costas D.; McDannold, Nathan

    2013-01-01

    Purpose: Ultrasound can be used to noninvasively produce different bioeffects via viscous heating, acoustic cavitation, or their combination, and these effects can be exploited to develop a wide range of therapies for cancer and other disorders. In order to accurately localize and control these different effects, imaging methods are desired that can map both temperature changes and cavitation activity. To address these needs, the authors integrated an ultrasound imaging array into an MRI-guided focused ultrasound (MRgFUS) system to simultaneously visualize thermal and mechanical effects via passive acoustic mapping (PAM) and MR temperature imaging (MRTI), respectively. Methods: The system was tested with an MRgFUS system developed for transcranial sonication for brain tumor ablation in experiments with a tissue mimicking phantom and a phantom-filled ex vivo macaque skull. In experiments on cavitation-enhanced heating, 10 s continuous wave sonications were applied at increasing power levels (30–110 W) until broadband acoustic emissions (a signature for inertial cavitation) were evident. The presence or lack of signal in the PAM, as well as its magnitude and location, were compared to the focal heating in the MRTI. Additional experiments compared PAM with standard B-mode ultrasound imaging and tested the feasibility of the system to map cavitation activity produced during low-power (5 W) burst sonications in a channel filled with a microbubble ultrasound contrast agent. Results: When inertial cavitation was evident, localized activity was present in PAM and a marked increase in heating was observed in MRTI. The location of the cavitation activity and heating agreed on average after registration of the two imaging modalities; the distance between the maximum cavitation activity and focal heating was −3.4 ± 2.1 mm and −0.1 ± 3.3 mm in the axial and transverse ultrasound array directions, respectively. Distortions and other MRI issues introduced small

  17. Integrated ultrasound and magnetic resonance imaging for simultaneous temperature and cavitation monitoring during focused ultrasound therapies.

    Science.gov (United States)

    Arvanitis, Costas D; McDannold, Nathan

    2013-11-01

    Ultrasound can be used to noninvasively produce different bioeffects via viscous heating, acoustic cavitation, or their combination, and these effects can be exploited to develop a wide range of therapies for cancer and other disorders. In order to accurately localize and control these different effects, imaging methods are desired that can map both temperature changes and cavitation activity. To address these needs, the authors integrated an ultrasound imaging array into an MRI-guided focused ultrasound (MRgFUS) system to simultaneously visualize thermal and mechanical effects via passive acoustic mapping (PAM) and MR temperature imaging (MRTI), respectively. The system was tested with an MRgFUS system developed for transcranial sonication for brain tumor ablation in experiments with a tissue mimicking phantom and a phantom-filled ex vivo macaque skull. In experiments on cavitation-enhanced heating, 10 s continuous wave sonications were applied at increasing power levels (30-110 W) until broadband acoustic emissions (a signature for inertial cavitation) were evident. The presence or lack of signal in the PAM, as well as its magnitude and location, were compared to the focal heating in the MRTI. Additional experiments compared PAM with standard B-mode ultrasound imaging and tested the feasibility of the system to map cavitation activity produced during low-power (5 W) burst sonications in a channel filled with a microbubble ultrasound contrast agent. When inertial cavitation was evident, localized activity was present in PAM and a marked increase in heating was observed in MRTI. The location of the cavitation activity and heating agreed on average after registration of the two imaging modalities; the distance between the maximum cavitation activity and focal heating was -3.4 ± 2.1 mm and -0.1 ± 3.3 mm in the axial and transverse ultrasound array directions, respectively. Distortions and other MRI issues introduced small uncertainties in the PAM

  18. Targeted endomyocardial biopsy guided by real-time cardiovascular magnetic resonance.

    Science.gov (United States)

    Unterberg-Buchwald, Christina; Ritter, Christian Oliver; Reupke, Verena; Wilke, Robin Niklas; Stadelmann, Christine; Steinmetz, Michael; Schuster, Andreas; Hasenfuß, Gerd; Lotz, Joachim; Uecker, Martin

    2017-04-19

    Endomyocardial biopsies (EMB) are an important diagnostic tool for myocarditis and other infiltrative cardiac diseases. Routinely, biopsies are obtained under fluoroscopic guidance with a substantial radiation burden. Despite procedural success, there is a large sampling error caused by missing the affected myocardium. Therefore, multiple (>6) biopsies are taken in the clinical setting. In cardiovascular magnetic resonance (CMR), late gadolinium enhancement (LGE) depicts areas of affected myocardium in myocarditis or in other infiltrative cardiomyopathies. Thus, targeted biopsy under real-time CMR image guidance might reduce the problem of sampling error. Seven minipigs of the Goettingen strain underwent radiofrequency ablation in the left ventricle. At least two focal lesions were induced on the lateral wall in five and the apex in two animals. Each ablation lesion was created by two consecutive 30 sec ablations (max. 30 W, temperature 60-64 °C). Biopsies were taken immediately after lesion induction using a commercially available 7 F conventional bioptome under fluoroscopic guidance at the ablation site. Afterwards the animals underwent CMR and lesion visualization by LGE at 3T. The lesions were then targeted and biopsied under CMR-guidance using a MR-conditional bioptome guided by a steerable catheter. Interactive real-time (RT) visualization of the intervention on an in-room monitor was based on radial FLASH with nonlinear inverse reconstruction (NLINV) at a temporal resolution of 42 ms. All samples underwent a standard histological evaluation. Radiofrequency ablation was successful in all animals. Fluoroscopy-guided biopsies were performed with a success rate of 6/6 minipigs - resulting in a nonlethal pericardial effusion in one animal. Visualization of radiofrequency lesions by CMR was successful in 7/7 minipig, i.e. at least one lesion was clearly visible. Localization and tracking of the catheters and the bioptome using interactive control of the

  19. Laser neurosurgery: A systematic analysis of magnetic resonance-guided laser interstitial thermal therapies.

    Science.gov (United States)

    Lagman, Carlito; Chung, Lawrance K; Pelargos, Panayiotis E; Ung, Nolan; Bui, Timothy T; Lee, Seung J; Voth, Brittany L; Yang, Isaac

    2017-02-01

    Magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) is a novel minimally invasive modality that uses heat from laser probes to destroy tissue. Advances in probe design, cooling mechanisms, and real-time MR thermography have increased laser utilization in neurosurgery. The authors perform a systematic analysis of two commercially available MRgLITT systems used in neurosurgery: the Visualase® thermal therapy and NeuroBlate® Systems. Data extraction was performed in a blinded fashion. Twenty-two articles were included in the quantitative synthesis. A total of 223 patients were identified with the majority having undergone treatment with Visualase (n=154, 69%). Epilepsy was the most common indication for Visualase therapy (n=8 studies, 47%). Brain mass was the most common indication for NeuroBlate therapy (n=3 studies, 60%). There were no significant differences, except in age, wherein the NeuroBlate group was nearly twice as old as the Visualase group (plength-of-stay (LOS) were non-significant when adjusted for age and number of patients. Laser neurosurgery has evolved over recent decades. Clinical indications are currently being defined and will continue to emerge as laser technologies become more sophisticated. Head-to-head comparison of these systems was difficult given the variance in indications (and therefore patient population) and disparate literature. Copyright © 2016. Published by Elsevier Ltd.

  20. Analysis of guided-resonance-based polarization beam splitting in photonic crystal slabs.

    Science.gov (United States)

    Kilic, Onur; Fan, Shanhui; Solgaard, Olav

    2008-11-01

    We present an analysis of the phase and amplitude responses of guided resonances in a photonic crystal slab. Through this analysis, we obtain the general rules and conditions under which a photonic crystal slab can be employed as a general elliptical polarization beam splitter, separating an incoming beam equally into its two orthogonal constituents, so that half the power is reflected in one polarization state, and half the power is transmitted in the other state. We show that at normal incidence a photonic crystal slab acts as a dual quarter-wave retarder in which the fast and slow axes are switched for reflection and transmission. We also analyze the case where such a structure operates at oblique incidences. As a result we show that the effective dielectric constant of the photonic crystal slab imposes the Brewster angle as a boundary, separating two ranges of angles with different mechanisms of polarization beam splitting. We show that the diattenuation can be tuned from zero to one to make the structure a circular or linear polarization beam splitter. We verify our analytical analysis through finite-difference time-domain simulations and experimental measurements at infrared wavelengths.

  1. MR thermometry in fat-containing tissues for MR-guided High Intensity Focused Ultrasound therapy

    NARCIS (Netherlands)

    Baron, Paul

    2015-01-01

    The aim of the research was to improve and apply MR thermometry techniques in fat -containing tissues. These thermometry methods were researched with the aim of applying them for MR-HIFU treatment of breast and liver tumors. The first study demonstrated the sensitivity of proton resonance frequency

  2. Laser Interstitial Thermal Therapy Technology, Physics of Magnetic Resonance Imaging Thermometry, and Technical Considerations for Proper Catheter Placement During Magnetic Resonance Imaging-Guided Laser Interstitial Thermal Therapy.

    Science.gov (United States)

    Patel, Nitesh V; Mian, Matthew; Stafford, R Jason; Nahed, Brian V; Willie, Jon T; Gross, Robert E; Danish, Shabbar F

    2016-12-01

    Laser-induced thermal therapy has become a powerful tool in the neurosurgical armamentarium. The physics of laser therapy are complex, but a sound understanding of this topic is clinically relevant, as many centers have incorporated it into their treatment algorithm, and educated patients are demanding consideration of its use for their disease. Laser ablation has been used for a wide array of intracranial lesions. Laser catheter placement is guided by stereotactic planning; however, as the procedure has popularized, the number of ways in which the catheter can be inserted has also increased. There are many technical nuances for laser placement, and, to date, there is not a clear understanding of whether any one technique is better than the other. In this review, we describe the basic physics of magnetic resonance-guided laser-induced thermal therapy and describe the several common techniques for accurate Visualase laser catheter placement in a stepwise fashion. MRg-LITT, magnetic resonance-guided laser-induced thermal therapyPAD, precision aiming device.

  3. Evaluation of MRI protocols for the assessment of lumbar facet joints after MR-guided focused ultrasound treatment

    OpenAIRE

    Krug, Roland; Do, Loi; Rieke, Viola; Wilson, Mark W.; Saeed, Maythem

    2016-01-01

    Background MR-guided focused ultrasound (MRgFUS) might be a very safe and effective minimally invasive technique to treat facet joint pain caused by arthritis and other degenerative changes. However, there are still safety concerns for this treatment and challenges regarding MR imaging and temperature mapping due to susceptibility effects between the bone and soft tissue near the joint, which has resulted in poor MR image quality. The goal of this research was to evaluate multiple magnetic re...

  4. Suitability of a tumour-mimicking material for the evaluation of high-intensity focused ultrasound ablation under magnetic resonance guidance

    Science.gov (United States)

    Pichardo, S.; Kivinen, J.; Melodelima, D.; Curiel, L.

    2013-04-01

    This study tests the suitability of a tumour-mimic for targeting magnetic resonance (MR)-guided high-intensity focused ultrasound (HIFU). An agarose-based tumour-mimic was injected as a warm solution that polymerized in tissue. Thermal characteristics and acoustic absorption of the mimic were observed within the values reported for tissues. The relaxation times at 3T were 1679 ± 15 ms for T1 and 41 ± 1 ms for T2. The mimic was clearly visible on in vivo images. With lower contrast the tumour-mimic was visible on T2-weighted images, where it was possible to detect the ablated tissue surrounding the mimic after sonications. HIFU sonications were performed to induce thermal ablation on and around the mimic using a Sonalleve system (Philips). MR thermometry maps were performed during HIFU. The average temperature when the sonication was done at the tumour-mimic was 67.6 ± 8.0 °C in vitro and 67.6 ± 5.0 °C in vivo. The average temperature for sonications at tissues was 68.4 ± 8.7 °C in vitro (liver) and 66.0 ± 2.6 °C in vivo (muscle), with no significant difference between tissue and tumour-mimic (p > 0.05). The tumour-mimic behaviour when using MR-guided HIFU was similar to tissues, showing that this mimic can be used as an alternative to tumour models for validating MR-guided HIFU devices targeting.

  5. Magnetic resonance image-guided brachytherapy for cervical cancer. Prognostic factors for survival

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon-Joo; Kim, Joo-Young [National Cancer Center, Proton Therapy Center, Goyang (Korea, Republic of); National Cancer Center, Center for Uterine Cancer, Goyang (Korea, Republic of); Kim, Youngkyong; Lim, Young Kyung; Jeong, Jonghwi [National Cancer Center, Proton Therapy Center, Goyang (Korea, Republic of); Jeong, Chiyoung [National Cancer Center, Proton Therapy Center, Goyang (Korea, Republic of); University of Ulsan College of Medicine, Department of Radiation Oncology, Asan Medical Center, Seoul (Korea, Republic of); Kim, Meyoung [National Cancer Center, Proton Therapy Center, Goyang (Korea, Republic of); Dongnam Inst. of Radiology and Medical Sciences, Research center, Busan (Korea, Republic of); Lim, Myong Cheol; Seo, Sang-Soo; Park, Sang-Yoon [National Cancer Center, Center for Uterine Cancer, Goyang (Korea, Republic of)

    2016-12-15

    The purpose of this work was to identify prognostic factors for survival after magnetic resonance image (MRI)-guided brachytherapy combined with external beam radiotherapy for cervical cancer. External beam radiotherapy of 45-50.4 Gy was delivered by either three-dimensional conformal radiotherapy or helical tomotherapy. Patients also received high-dose-rate MRI-guided brachytherapy of 5 Gy in 6 fractions. We analyzed 128 patients with International Federation of Gynecology and Obstetrics stage IB-IVB cervical cancer who underwent MRI-guided brachytherapy. Most patients (96 %) received concurrent chemotherapy. Pelvic lymph node metastases and para-aortic lymphadenopathies were found in 62 % and 14 % of patients, respectively. The median follow-up time was 44 months. Complete remission was achieved in 119 of 128 patients (93 %). The 5-year local recurrence-free, cancer-specific, and overall survival rates were 94, 89, and 85 %, respectively. Negative pelvic lymphadenopathy, gross tumor volume (GTV) dose covering 90 % of the target (GTV D90) of >110 Gy, and treatment duration ≤56 days were associated with better overall survival in univariate analyses. Multivariable analysis showed that GTV D90 of >110 Gy and treatment duration ≤56 days were possibly associated with overall survival with near-significant P-values of 0.062 and 0.073, respectively. The outcome of MRI-guided brachytherapy combined with external beam radiotherapy in patients with cervical cancer was excellent. GTV D90 of >110 Gy and treatment duration ≤56 days were potentially associated with overall survival. (orig.) [German] Ziel der Arbeit war es, prognostische Faktoren nach magnetresonanztomographisch (MRT-)gesteuerter Brachytherapie in Verbindung mit externer Strahlentherapie fuer Gebaermutterhalskrebs zu identifizieren. Externe Strahlentherapie von 45-50,4 Gy erfolgte entweder mittels dreidimensionaler konformaler Strahlentherapie oder helikaler Tomotherapie. Die Patientinnen erhielten auch

  6. Intrinsic Tryptophan Fluorescence in the Detection and Analysis of Proteins: A Focus on Förster Resonance Energy Transfer Techniques

    Directory of Open Access Journals (Sweden)

    Amar B. T. Ghisaidoobe

    2014-12-01

    Full Text Available F resonance energy transfer (FRET occurs when the distance between a donor fluorophore and an acceptor is within 10 nm, and its application often necessitates fluorescent labeling of biological targets. However, covalent modification of biomolecules can inadvertently give rise to conformational and/or functional changes. This review describes the application of intrinsic protein fluorescence, predominantly derived from tryptophan (\\(\\uplambda_{\\textsc{ex}}\\sim\\ nm, \\(\\uplambda_{\\textsc{em}}\\sim\\ 350 nm, in protein-related research and mainly focuses on label-free FRET techniques. In terms of wavelength and intensity, tryptophan fluorescence is strongly influenced by its (or the proteinlocal environment, which, in addition to fluorescence quenching, has been applied to study protein conformational changes. Intrinsic F resonance energy transfer (iFRET, a recently developed technique, utilizes the intrinsic fluorescence of tryptophan in conjunction with target-specific fluorescent probes as FRET donors and acceptors, respectively, for real time detection of native proteins.

  7. Redefining leadership education in graduate public health programs: prioritization, focus, and guiding principles

    National Research Council Canada - National Science Library

    Lachance, Jennifer A; Oxendine, Jeffrey S

    2015-01-01

    .... Leadership development initiatives should be practice based, process focused, interdisciplinary, diversity based, adaptive, experimental, innovative, and empowering, and they should encourage authenticity...

  8. Using ferromagnetic nanoparticles with low Curie temperature for magnetic resonance imaging-guided thermoablation

    Science.gov (United States)

    Herynek, Vít; Turnovcová, Karolína; Veverka, Pavel; Dědourková, Tereza; Žvátora, Pavel; Jendelová, Pavla; Gálisová, Andrea; Kosinová, Lucie; Jiráková, Klára; Syková, Eva

    2016-01-01

    Introduction Magnetic nanoparticles (NPs) represent a tool for use in magnetic resonance imaging (MRI)-guided thermoablation of tumors using an external high-frequency (HF) magnetic field. To avoid local overheating, perovskite NPs with a lower Curie temperature (Tc) were proposed for use in thermotherapy. However, deposited power decreases when approaching the Curie temperature and consequently may not be sufficient for effective ablation. The goal of the study was to test this hypothesis. Methods Perovskite NPs (Tc =66°C–74°C) were characterized and tested both in vitro and in vivo. In vitro, the cells suspended with NPs were exposed to a HF magnetic field together with control samples. In vivo, a NP suspension was injected into a induced tumor in rats. Distribution was checked by MRI and the rats were exposed to a HF field together with control animals. Apoptosis in the tissue was evaluated. Results and discussion In vitro, the high concentration of suspended NPs caused an increase of the temperature in the cell sample, leading to cell death. In vivo, MRI confirmed distribution of the NPs in the tumor. The temperature in the tumor with injected NPs did not increase substantially in comparison with animals without particles during HF exposure. We proved that the deposited power from the NPs is too small and that thermoregulation of the animal is sufficient to conduct the heat away. Histology did not detect substantially higher apoptosis in NP-treated animals after ablation. Conclusion Magnetic particles with low Tc can be tracked in vivo by MRI and heated by a HF field. The particles are capable of inducing cell apoptosis in suspensions in vitro at high concentrations only. However, their effect in the case of extracellular deposition in vivo is questionable due to low deposited power and active thermoregulation of the tissue. PMID:27540292

  9. FOCUS surface water scenario help (SWASH) Version 1.1; user's guide Version 1.1

    NARCIS (Netherlands)

    Berg, van den F.; Adriaanse, P.I.; Roller, te J.A.

    2005-01-01

    The user-friendly shell SWASH, acronym for Surface WAter Scenarios Help, assists the user in calculating pesticide exposure concentrations in the EU FOCUS surface water scenarios. It is part of the exposure calculation procedure developed by the FOCUS Surface Water Scenarios Working Group, which has

  10. In vivo evaluation of multi-echo hybrid PRF/T1 approach for temperature monitoring during breast MR-guided focused ultrasound surgery treatments.

    Science.gov (United States)

    Todd, Nick; Diakite, Mahamadou; Payne, Allison; Parker, Dennis L

    2014-09-01

    To evaluate the precision of in vivo temperature measurements in adipose and glandular breast tissue using a multi-echo hybrid PRF/T1 pulse sequence. A high-bandwidth, multi-echo hybrid PRF/T1 sequence was developed for monitoring temperature changes simultaneously in fat- and water-based tissues. The multiple echoes were combined with the optimal weightings for magnitude and phase images, allowing for precise measurement of both T1 and the proton resonance frequency (PRF) shift. The sequence was tested during in vivo imaging of 10 healthy volunteers in a breast-specific MR-guided focused ultrasound system and also during focused ultrasound heating of excised breast adipose tissue. The in vivo results indicated that the sequence can measure PRF temperatures with 1.25 × 1.25 × 3.5 mm resolution, 1.9 s temporal resolution, and 1.0°C temperature precision, and can measure T1 values with 3.75 × 3.75 × 3.5 mm resolution, 3.8 s temporal resolution, and 2.5%-4.8% precision. The excised tissue heating experiments demonstrate the sequence's ability to monitor temperature changes simultaneously in water- and fat-based tissues. The addition of a high-bandwidth, multi-echo readout to the hybrid PRF/T1 sequence improves the precision of each measurement, providing a sequence that will be beneficial to several MR-guided thermal therapies. Copyright © 2013 Wiley Periodicals, Inc.

  11. Ultrasound-Guided Obturator Nerve Block: A Focused Review on Anatomy and Updated Techniques.

    Science.gov (United States)

    Yoshida, Takayuki; Nakamoto, Tatsuo; Kamibayashi, Takahiko

    2017-01-01

    This review outlines the anatomy of the obturator nerve and the indications for obturator nerve block (ONB). Ultrasound-guided ONB techniques and unresolved issues regarding these procedures are also discussed. An ONB is performed to prevent thigh adductor jerk during transurethral resection of bladder tumor, provide analgesia for knee surgery, treat hip pain, and improve persistent hip adductor spasticity. Various ultrasound-guided ONB techniques can be used and can be classified according to whether the approach is distal or proximal. In the distal approach, a transducer is placed at the inguinal crease; the anterior and posterior branches of the nerve are then blocked by two injections of local anesthetic directed toward the interfascial planes where each branch lies. The proximal approach comprises a single injection of local anesthetic into the interfascial plane between the pectineus and obturator externus muscles. Several proximal approaches involving different patient and transducer positions are reported. The proximal approach may be superior for reducing the dose of local anesthetic and providing successful blockade of the obturator nerve, including the hip articular branch, when compared with the distal approach. This hypothesis and any differences between the proximal ONB techniques need to be explored in future studies.

  12. Ultrasound-Guided Obturator Nerve Block: A Focused Review on Anatomy and Updated Techniques

    Directory of Open Access Journals (Sweden)

    Takayuki Yoshida

    2017-01-01

    Full Text Available This review outlines the anatomy of the obturator nerve and the indications for obturator nerve block (ONB. Ultrasound-guided ONB techniques and unresolved issues regarding these procedures are also discussed. An ONB is performed to prevent thigh adductor jerk during transurethral resection of bladder tumor, provide analgesia for knee surgery, treat hip pain, and improve persistent hip adductor spasticity. Various ultrasound-guided ONB techniques can be used and can be classified according to whether the approach is distal or proximal. In the distal approach, a transducer is placed at the inguinal crease; the anterior and posterior branches of the nerve are then blocked by two injections of local anesthetic directed toward the interfascial planes where each branch lies. The proximal approach comprises a single injection of local anesthetic into the interfascial plane between the pectineus and obturator externus muscles. Several proximal approaches involving different patient and transducer positions are reported. The proximal approach may be superior for reducing the dose of local anesthetic and providing successful blockade of the obturator nerve, including the hip articular branch, when compared with the distal approach. This hypothesis and any differences between the proximal ONB techniques need to be explored in future studies.

  13. Plasma focus sources: Supplement to the neutron resonance radiography workshop proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Nardi, V.; Brzosko, J.

    1989-01-01

    Since their discovery, plasma focus discharges have been recognized as very intense pulsed sources of deuterium-deuterium (D-D) or deuterium-tritium (D-T) fusion-reaction neutrons, with outstanding capabilities. Specifically, the total neutron emission/shot, YN, and the rate of neutron emission, Y/sub n/, of an optimized plasma focus (PF) are higher than the corresponding quantities observed in any other type of pinched discharge at the same level of powering energy W/sub 0/. Recent developments have led to the concept and experimental demonstration of an Advanced Plasma Focus System (APF) that consists of a Mather-geometry plasma focus in which field distortion elements (FDEs) are inserted in the inter-electrode gap for increasing the neutron yield/shot, Y/sub n/. The FDE-induced redistribution of the plasma current increases Y/sub n/ by a factor approx. =5-10 above the value obtained without FDEs under otherwise identical conditions of operation of the plasma focus. For example, an APF that is fed by a fast capacitor bank with an energy, W/sub 0/ = 6kJ, and voltage, V/sub 0/ = 16.5 kV provides Y/sub n/ /congruent/ 4 /times/ 10/sup 9/ D-D neutrons/shot (pure D/sub 2/ filling) and Y/sub n/ = 4 /times/ 10/sup 11/ D-T neutrons/shot (filling is 50% deuterium and 50% tritium). The FDE-induced increase of Y/sub n/ for fixed values of (W/sub 0/, V/sub 0/), the observed scaling law Y/sub n/ /proportional to/ W/sub 0//sup 2/ for optimized plasma focus systems, and our experience with neutron scattering in bulk objects lead us to the conclusion that we can use an APF as a source of high-intensity neutron pulses (10/sup 14/ n/pulse) in the field off neutron radiography (surface and bulk) with a nanosecond or millisecond time resolution.

  14. Resonance

    DEFF Research Database (Denmark)

    Petersen, Nils Holger

    2014-01-01

    A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....

  15. Reflective Practice: Using Focus Groups to Determine Family Priorities and Guide Social Pragmatic Program Development

    Science.gov (United States)

    Theadore, Geraldine; Laurent, Amy; Kovarsky, Dana; Weiss, Amy L.

    2011-01-01

    Reflective practice requires that professionals carefully examine and integrate multiple sources of information when designing intervention and evaluating its effectiveness. This article describes the use of focus group discussion as a form of qualitative research for understanding parents' perspectives of a university-based intervention program…

  16. Focusing through the rib cage for MR-guided transcostal FUS

    Science.gov (United States)

    Gao, J.; Volovick, A.; Pekelny, Y.; Huang, ZH.; Cochran, S.; Melzer, A.

    2012-10-01

    The rib cage presents a significant obstacle in transcostal focused ultrasound surgery (FUS). This paper proposes a geometric solution, based on central projection from the focus to identify transducer elements affected by ribs shadowing which should be switched off. Its effectiveness in phantom experiments and simulations is reported, and ways are discussed to further reduce energy deposition on the ribs while enhancing heating at the focus. A tissue-mimicking phantom with phantom of ribs was sonicated using a 208-element 1.15 MHz bowl transducer and a 1000-element 550 kHz planar matrix transducer (both ExAblate, InSightec, Israel). The temperature evolution was monitored with real-time MRI thermometry (GE, USA). Numerical simulations were performed with FEA software (PZFlex, Weidlinger Associates, USA) to investigate different skin-focus and transducer-rib distances. The temperature rise near the ribs was reduced to 16°C and 4°C for the 1.15 MHz and 550 kHz transducers respectively. With the 1.15 MHz transducer, the focal temperature reached the ablation threshold. These measurements are in good agreement with simulations. The proposed method shows promising results for transcostal FUS. Residual temperature rise on the ribs can be further reduced by active cooling, allowing the higher energies essential for efficient ablation.

  17. Using Songbird Monitoring to Guide and Evaluate Riparian Restoration in Salmonid-Focused Stream Rehabilitation Projects

    Science.gov (United States)

    Ryan D. Burnett; Thomas Gardali; Geoffrey R. Geupel

    2005-01-01

    A restoration effort, primarily focused on reducing stranding and improving passage of anadromous fish, has been undertaken along sections of lower Clear Creek, Shasta County, California. Similar projects are occurring throughout California and, indeed, all of North America. To monitor the effects of these efforts at Clear Creek we implemented a multi-faceted songbird...

  18. Online Magnetic Resonance Image Guided Adaptive Radiation Therapy: First Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, Sahaja; Fischer-Valuck, Benjamin W.; Kashani, Rojano; Parikh, Parag; Yang, Deshan; Zhao, Tianyu; Green, Olga; Wooten, Omar; Li, H. Harold; Hu, Yanle; Rodriguez, Vivian; Olsen, Lindsey; Robinson, Clifford; Michalski, Jeff; Mutic, Sasa; Olsen, Jeffrey, E-mail: jolsen@radonc.wustl.edu

    2016-02-01

    Purpose: To demonstrate the feasibility of online adaptive magnetic resonance (MR) image guided radiation therapy (MR-IGRT) through reporting of our initial clinical experience and workflow considerations. Methods and Materials: The first clinically deployed online adaptive MR-IGRT system consisted of a split 0.35T MR scanner straddling a ring gantry with 3 multileaf collimator-equipped {sup 60}Co heads. The unit is supported by a Monte Carlo–based treatment planning system that allows real-time adaptive planning with the patient on the table. All patients undergo computed tomography and MR imaging (MRI) simulation for initial treatment planning. A volumetric MRI scan is acquired for each patient at the daily treatment setup. Deformable registration is performed using the planning computed tomography data set, which allows for the transfer of the initial contours and the electron density map to the daily MRI scan. The deformed electron density map is then used to recalculate the original plan on the daily MRI scan for physician evaluation. Recontouring and plan reoptimization are performed when required, and patient-specific quality assurance (QA) is performed using an independent in-house software system. Results: The first online adaptive MR-IGRT treatments consisted of 5 patients with abdominopelvic malignancies. The clinical setting included neoadjuvant colorectal (n=3), unresectable gastric (n=1), and unresectable pheochromocytoma (n=1). Recontouring and reoptimization were deemed necessary for 3 of 5 patients, and the initial plan was deemed sufficient for 2 of the 5 patients. The reasons for plan adaptation included tumor progression or regression and a change in small bowel anatomy. In a subsequently expanded cohort of 170 fractions (20 patients), 52 fractions (30.6%) were reoptimized online, and 92 fractions (54.1%) were treated with an online-adapted or previously adapted plan. The median time for recontouring, reoptimization, and QA was 26

  19. Magnetic resonance spectroscopic imaging 3T and prostate cancer: correlation with transperineal ultrasound guided prostate biopsy.

    Science.gov (United States)

    Castellucci, Roberto; Altieri, Vincenzo Maria; Marchioni, Michele; Castellan, Pietro; Pellegrini, Maurizio; Álvarez-Maestro, Mario; Sánchez-Gómez, Javier; De Francesco, Piergustavo; Ingrosso, Manuela; Tartaro, Armando; Tenaglia, Raffaele Lanfranco

    2015-06-01

    The aim of our study was to correlate the results obtained by 3T Magnetic Resonance Spectroscopic Imaging (MRSI3T) with those obtained by histological examination of samples of the trans-perineal ultrasound-guided prostate biopsy (TPUS-B). 34 patients were enrolled in the study. All patients had a clinical suspicion of cancer due to increased PSA and/or positive digital rectal examination. Patients were subjected to an MRSI 3T examination and subsequently to TPUS-B. Of the 22 (22/34) patients who presented abnormalities MRSI at 3T, 9 had a histological diagnosis of Prostate adenocarcinoma. Of the remaining 13 patients, 6 were found to be histologically positive for Benign Prostatic Hypertrophy and 7 Chronic Interstitial Inflammation or High Grade Prostatic Intraepithelial Neoplasia. 12 (12/34) patients found to have no peripheral alterations in their prostate on 3T MRSI, none were positive for ADK or inflammation on histology. The sensitivity, specificity, positive predictive value and negative predictive value were 100%, 48%, 40% and 100% respectively. In this study, we correlated the values obtained from 3T MRSI with the results of histologically examined prostate biopsies. Our work shows that 72.8% of the voxels in which there was a change in ratio of Cit/(Cho + Cr), corresponded to areas of prostate tissue disease. Of these, 73.2% were positive for ADK and 26.8% for CII or HG PIN. In literature, it is noted that PCa can be distinguished from areas of benign tissue, in the peripheral zone, on the basis of the values of the ratio Cit/(Cho + Cr) (17), although some benign conditions, such as prostatitis or PINHG, can alter these values (18-19). In conclusion, the use of MRSI 3T before performing prostate biopsies may represent a valid aid for the urologist in the diagnosis of PCa, allowing them to avoid unnecessary prostate biopsies that may be negative. Furthermore, it would also be possible to reduce the total number of biopsies, thus decreasing patient exposure

  20. Effect of Prostate Magnetic Resonance Imaging/Ultrasound Fusion-guided Biopsy on Radiation Treatment Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Aaron; Valle, Luca F.; Shankavaram, Uma; Krauze, Andra; Kaushal, Aradhana; Schott, Erica; Cooley-Zgela, Theresa [Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Wood, Bradford [Center for Interventional Oncology, National Institutes of Health, Bethesda, Maryland (United States); Pinto, Peter [Urologic Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Choyke, Peter; Turkbey, Baris [Molecular Imaging Program, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States); Citrin, Deborah E., E-mail: citrind@mail.nih.gov [Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland (United States)

    2017-04-01

    Purpose: Targeted magnetic resonance imaging (MRI)/ultrasound fusion prostate biopsy (MRI-Bx) has recently been compared with the standard of care extended sextant ultrasound-guided prostate biopsy (SOC-Bx), with the former associated with an increased rate of detection of clinically significant prostate cancer. The present study sought to determine the influence of MRI-Bx on radiation therapy and androgen deprivation therapy (ADT) recommendations. Methods and Materials: All patients who had received radiation treatment and had undergone SOC-Bx and MRI-Bx at our institution were included. Using the clinical T stage, pretreatment prostate-specific antigen, and Gleason score, patients were categorized into National Comprehensive Cancer Network risk groups and radiation treatment or ADT recommendations assigned. Intensification of the recommended treatment after multiparametric MRI, SOC-Bx, and MRI-Bx was evaluated. Results: From January 2008 to January 2016, 73 patients received radiation therapy at our institution after undergoing a simultaneous SOC-Bx and MRI-Bx (n=47 with previous SOC-Bx). Repeat SOC-Bx and MRI-Bx resulted in frequent upgrading compared with previous SOC-Bx (Gleason score 7, 6.7% vs 44.6%; P<.001; Gleason score 8-10, 2.1% vs 38%; P<.001). MRI-Bx increased the proportion of patients classified as very high risk from 24.7% to 41.1% (P=.027). Compared with SOC-Bx alone, including the MRI-Bx findings resulted in a greater percentage of pathologically positive cores (mean 37% vs 44%). Incorporation of multiparametric MRI and MRI-Bx results increased the recommended use and duration of ADT (duration increased in 28 of 73 patients and ADT was added for 8 of 73 patients). Conclusions: In patients referred for radiation treatment, MRI-Bx resulted in an increase in the percentage of positive cores, Gleason score, and risk grouping. The benefit of treatment intensification in accordance with the MRI-Bx findings is unknown.

  1. Resonances

    DEFF Research Database (Denmark)

    an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...... of the book: how connotations of past meanings may resonate through time, in new contexts, assuming new meanings without surrendering the old....

  2. Modeling-based design and assessment of an acousto-optic guided high-intensity focused ultrasound system

    Science.gov (United States)

    Adams, Matthew T.; Cleveland, Robin O.; Roy, Ronald A.

    2017-01-01

    Real-time acousto-optic (AO) sensing has been shown to noninvasively detect changes in ex vivo tissue optical properties during high-intensity focused ultrasound (HIFU) exposures. The technique is particularly appropriate for monitoring noncavitating lesions that offer minimal acoustic contrast. A numerical model is presented for an AO-guided HIFU system with an illumination wavelength of 1064 nm and an acoustic frequency of 1.1 MHz. To confirm the model's accuracy, it is compared to previously published experimental data gathered during AO-guided HIFU in chicken breast. The model is used to determine an optimal design for an AO-guided HIFU system, to assess its robustness, and to predict its efficacy for the ablation of large volumes. It was found that a through transmission geometry results in the best performance, and an optical wavelength around 800 nm was optimal as it provided sufficient contrast with low absorption. Finally, it was shown that the strategy employed while treating large volumes with AO guidance has a major impact on the resulting necrotic volume and symmetry.

  3. The family physician's perceived role in preventing and guiding hospital admissions at the end of life: a focus group study.

    Science.gov (United States)

    Reyniers, Thijs; Houttekier, Dirk; Pasman, H Roeline; Stichele, Robert Vander; Cohen, Joachim; Deliens, Luc

    2014-01-01

    Family physicians play a pivotal role in providing end-of-life care and in enabling terminally ill patients to die in familiar surroundings. The purpose of this study was to explore the family physicians' perceptions of their role and the difficulties they have in preventing and guiding hospital admissions at the end of life. Five focus groups were held with family physicians (N= 39) in Belgium. Discussions were transcribed verbatim and analyzed using a constant comparative approach. Five key roles in preventing and guiding hospital admissions at the end of life were identified: as a care planner, anticipating future scenarios; as an initiator of decisions in acute situations, mostly in an advisory manner; as a provider of end-of-life care, in which competency and attitude is considered important; as a provider of support, particularly by being available during acute situations; and as a decision maker, taking overall responsibility. Family physicians face many different and complex roles and difficulties in preventing and guiding hospital admissions at the end of life. Enhancing the family physician's role as a gatekeeper to hospital services, offering the physicians more end-of-life care training, and developing or expanding initiatives to support them could contribute to a lower proportion of hospital admissions at the end of life. © 2014 Annals of Family Medicine, Inc.

  4. Redefining Leadership Education in Graduate Public Health Programs: Prioritization, Focus, and Guiding Principles

    Science.gov (United States)

    Oxendine, Jeffrey S.

    2015-01-01

    Public health program graduates need leadership skills to be effective in the complex, changing public health environment. We propose a new paradigm for schools of public health in which technical and leadership skills have equal priority as core competencies for graduate students. Leadership education should focus on the foundational skills necessary to effect change independent of formal authority, with activities offered at varying levels of intensity to engage different students. Leadership development initiatives should be practice based, process focused, interdisciplinary, diversity based, adaptive, experimental, innovative, and empowering, and they should encourage authenticity. Leadership training in graduate programs will help lay the groundwork for public health professionals to have an immediate impact in the workforce and to prioritize continuous leadership development throughout their careers. PMID:25706021

  5. Redefining leadership education in graduate public health programs: prioritization, focus, and guiding principles.

    Science.gov (United States)

    Lachance, Jennifer A; Oxendine, Jeffrey S

    2015-03-01

    Public health program graduates need leadership skills to be effective in the complex, changing public health environment. We propose a new paradigm for schools of public health in which technical and leadership skills have equal priority as core competencies for graduate students. Leadership education should focus on the foundational skills necessary to effect change independent of formal authority, with activities offered at varying levels of intensity to engage different students. Leadership development initiatives should be practice based, process focused, interdisciplinary, diversity based, adaptive, experimental, innovative, and empowering, and they should encourage authenticity. Leadership training in graduate programs will help lay the groundwork for public health professionals to have an immediate impact in the workforce and to prioritize continuous leadership development throughout their careers.

  6. Magnetic resonance-compatible robotic and mechatronics systems for image-guided interventions and rehabilitation: a review study.

    Science.gov (United States)

    Tsekos, Nikolaos V; Khanicheh, Azadeh; Christoforou, Eftychios; Mavroidis, Constantinos

    2007-01-01

    The continuous technological progress of magnetic resonance imaging (MRI), as well as its widespread clinical use as a highly sensitive tool in diagnostics and advanced brain research, has brought a high demand for the development of magnetic resonance (MR)-compatible robotic/mechatronic systems. Revolutionary robots guided by real-time three-dimensional (3-D)-MRI allow reliable and precise minimally invasive interventions with relatively short recovery times. Dedicated robotic interfaces used in conjunction with fMRI allow neuroscientists to investigate the brain mechanisms of manipulation and motor learning, as well as to improve rehabilitation therapies. This paper gives an overview of the motivation, advantages, technical challenges, and existing prototypes for MR-compatible robotic/mechatronic devices.

  7. Fluoroscopy-Guided Sacroplasty: Special Focus on Preoperative Planning from Three-Dimensional Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gjertsen, Oe.; Schellhorn, T.; Nakstad, P.H. (Dept. of Neuroradiology, Division of Medical Services, Ullevl Univ. Hospital, Univ. of Oslo, Oslo (Norway))

    2008-11-15

    Background: Osteoporotic sacral insufficiency fractures are usually spontaneous or caused by discrete traumas. The fluoroscopic anatomy of the sacrum can be difficult to understand, and this is why sacroplasty is considered more challenging than ordinary vertebroplasties. Purpose: To demonstrate the planning of the procedure and the effectiveness of treatment with sacroplasty by means of three-dimensional computed tomography (3D CT) by combining multiplanar reconstructions (MPR) and volume-rendering technique (VRT). Material and Methods: Five elderly, osteoporotic patients with intense pelvic and hip pain underwent weeks of inconclusive clinical and radiological diagnostic efforts. Correct diagnosis was finally attained with magnetic resonance imaging (MRI) and CT. Plain radiographs rarely show fractures, and MR or CT examinations are necessary to demonstrate longitudinal fractures. The procedures were performed with digital biplane equipment using preoperative 3D CT planning procedures. Polymethyl methacrylate (PMMA) was injected to fill the fracture sites. Results: The fractures were successfully treated with sacroplasty using PMMA. A new technique, which involves placing the needles along the long axis of the sacrum, was optimized to the individual patients' fractures and sacral anatomy by meticulous planning on a workstation with 3D CT data sets. It was technically successful in all five cases. Four of the five patients had sustained pain relief. Conclusion: Sacral insufficiency fractures are not uncommon and should be considered in the elderly population with low back pain. Sacroplasty using the optimized 'long-axis technique' gave almost immediate pain relief for all five patients in our study material. No complications were observed.

  8. Non-invasive thermoablation of symptomatic uterine fibroids with magnetic resonance-guided high-energy ultrasound; Nichtinvasive Thermoablation symptomatischer Uterusmyome mit MR-gesteuertem hochenergetischem Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Eckey, T. [Universitaetsklinikum Schleswig-Holstein, Campus Luebeck, Klinik fuer Radiologie und Nuklearmedizin, Luebeck (Germany); Universitaetsklinikum Schleswig-Holstein, Campus Luebeck, Institut fuer Neuroradiologie, Luebeck (Germany); Neumann, A.; Barkhausen, J.; Hunold, P. [Universitaetsklinikum Schleswig-Holstein, Campus Luebeck, Klinik fuer Radiologie und Nuklearmedizin, Luebeck (Germany); Bohlmann, M.K. [Universitaetsklinikum Schleswig-Holstein, Campus Luebeck, Klinik fuer Frauenheilkunde und Geburtshilfe, Luebeck (Germany)

    2011-07-15

    Uterine fibroids are the most common benign tumors in postmenopausal women which can cause severe symptoms and considerably reduce the quality of life. Patients are requesting minimally invasive, organ-saving therapies increasingly more often and magnetic resonance-guided focused ultrasound is a promising new technology which even surpasses these requirements as it is a totally non-invasive approach. The possibility of real-time temperature mapping allows a safe and precise thermal ablation of uterine fibroids. The rate of adverse events is low and safety and efficiency have been proven in several clinical studies. Further studies will have to be carried out to demonstrate long-term success and comparability to the established therapies and clarify if focused ultrasound is a safe treatment for women with the desire for future pregnancy. The MR-guided focused ultrasound technique is an effective and gentle treatment for uterine fibroids and holds a great potential for further indications. (orig.) [German] Das Uterusmyom ist der haeufigste benigne Tumor praemenopausaler Frauen. Aufgrund der manchmal ausgepraegten Symptomatik ist eine effektive Therapie fuer eine Verbesserung der Lebensqualitaet der Betroffenen entscheidend. Der ''high-intensity focused ultrasound'' (HIFU) stellt als organerhaltende und nichtinvasive Therapiemethode eine viel versprechende Behandlungsalternative dar, die dem hohen Sicherheitsbeduerfnis und dem steigenden Wunsch der Patientinnen nach moeglichst geringer Invasivitaet gerecht wird. Der MRT-gesteuerte hochenergetische Ultraschall erlaubt aufgrund der Echtzeittemperaturueberwachung eine praezise und sichere Thermoablation der Myome, die bei bis zu 90% der Patientinnen zu einer signifikanten Symptombesserung fuehrt. Das Nebenwirkungsprofil erweist sich als ausgesprochen guenstig. Bisherige klinische Studien konnten Sicherheit, Effektivitaet und therapeutischen Nutzen sowie eine deutlich kuerzere Rekonvaleszenz im

  9. The Value of Proton Magnetic Resonance Spectroscopy in High-Intensity Focused Ultrasound Treatment of Experimental Liver Cancer

    Directory of Open Access Journals (Sweden)

    Zhuo-yue Tang

    2015-06-01

    Full Text Available High-intensity focused ultrasound (HIFU is a rapidly developing, non-invasive technique for local treatment of solid tumors that produce coagulative tumor necrosis. This study is aimed to investigate the feasibility of proton magnetic resonance spectroscopy (MRS on early assessing treatment of HIFU ablation in rabbit with VX2 liver tumor. HIFU ablation was performed on normal liver and VX2 tumor in rabbit, and MRS was performed on normal liver and VX2 tumor before and 2 days after 100% HIFU ablation or 80% ablation in tumor volume. Choline (Cho and choline/lipid (Cho/Lip ratios between complete and partial HIFU ablation of tumor were compared. Tissues were harvested and sequentially sliced to confirm the necrosis. In normal liver, the Cho value liver was not obviously changed after HIFU (P > .05, but the Cho/Lip ratio was decreased (P .05; however, the Cho value in partial ablation was still higher than that in normal liver before or in tumor after complete HIFU treatment due to the residual part of tumors, and Cho/Lip ratio is lower than that in complete HIFU treatment (P < .001. The changes in MRS parameters were consistent with histopathologic changes of the tumor tissues after treatment. MRS could differentiate the complete tumor necrosis from residual tumor tissue, when combined with magnetic resonance imaging. We conclude that MRS may be applied as an important, non-invasive biomarker for monitoring the thoroughness of HIFU ablation.

  10. Contactless transport of matter in the first five resonance modes of a line-focused acoustic manipulator.

    Science.gov (United States)

    Foresti, Daniele; Nabavi, Majid; Poulikakos, Dimos

    2012-02-01

    The first five resonance modes for transport of matter in a line-focused acoustic levitation system are investigated. Contactless transport was achieved by varying the height between the radiating plate and the reflector. Transport and levitation of droplets in particular involve two limits of the acoustic forces. The lower limit corresponds to the minimum force required to overcome the gravitational force. The upper limit corresponds to the maximum acoustic pressure beyond which atomization of the droplet occurs. As the droplet size increases, the lower limit increases and the upper limit decreases. Therefore to have large droplets levitated, relatively flat radiation pressure amplitude during the translation is needed. In this study, using a finite element model, the Gor'kov potential was calculated for different heights between the reflector and the radiating plate. The application of the Gor'kov potential was extended to study the range of droplet sizes for which the droplets can be levitated and transported without atomization. It was found that the third resonant mode (H(3)-mode) represents the best compromise between high levitation force and smooth pattern transition, and water droplets of millimeter radius can be levitated and transported. The H(3)-mode also allows for three translation lines in parallel. © 2012 Acoustical Society of America

  11. Stand-off explosive detection utilizing low power stimulated emission nuclear quadrupole resonance detection and subwavelength focusing wideband super lens

    Science.gov (United States)

    Apostolos, John; Mouyos, William; Feng, Judy; Chase, Walter

    2015-05-01

    The need for advanced techniques to detect improvised explosive devices (IED) at stand-off distances greater than ten (10) meters has driven AMI Research and Development (AMI) to develop a solution to detect and identify the threat utilizing a forward looking Synthetic Aperture Radar (SAR) combined with our CW radar technology Nuclear Quadrupole Resonance (NQR) detection system. The novel features include a near-field sub-wavelength focusing antenna, a wide band 300 KHz to 300 MHz rapidly scanning CW radar facilitated by a high Q antenna/tuner, and an advanced processor utilizing Rabi transitions where the nucleus oscillates between states under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. AMI's Sub-wavelength Focusing Wide Band Super Lens uses a Near-Field SAR, making detection possible at distances greater than ten (10) meters. This super lens is capable of operating on the near-field and focusing electromagnetic waves to resolutions beyond the diffraction limit. When applied to the case of a vehicle approaching an explosive hazard the methodologies of synthetic aperture radar is fused with the array based super resolution and the NQR data processing detecting the explosive hazard.

  12. [A tumour-mimic pig liver model for guiding focused ultrasound thermal ablation].

    Science.gov (United States)

    Melodelima, D; N'djin, Wa; Parmentier, H; Chesnais, S; Rivoire, M; Chapelon, J-Y

    2007-11-01

    There is no established liver tumour model in pigs to study the efficacy of ablative treatment options available for the treatment of liver tumours by physical agents. A tumour-mimic model visible with high contrast on sonograms and on gross pathology has been studied at mid-term on 20 pigs. The aim was to determine if these tumour-mimics are well tolerated and can be used to validate the use of thermal therapies at a preclinical stage. The dimensions of the tumour-mimics measured on sonograms were reproducible (diameter: 9.6 +/- 1.9 mm) and correlated with those performed in gross pathology (R(2)=0.73). The accuracy of focused ultrasound thermal therapy can be evaluated preclinically using these tumour-mimics.

  13. Volumetric MR-Guided High-Intensity Focused Ultrasound with Direct Skin Cooling for the Treatment of Symptomatic Uterine Fibroids: Proof-of-Concept Study

    Directory of Open Access Journals (Sweden)

    Marlijne E. Ikink

    2015-01-01

    Full Text Available Objective. To prospectively assess the safety and technical feasibility of volumetric magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU ablation with direct skin cooling (DISC during treatment of uterine fibroids. Methods. In this proof-of-concept study, eight patients were consecutively selected for clinical MR-HIFU ablation of uterine fibroids with the use of an additional DISC device to maintain a constant temperature (T≈20°C at the interface between the HIFU table top and the skin. Technical feasibility was verified by successful completion of MR-HIFU ablation. Contrast-enhanced T1-weighted MRI was used to measure the treatment effect (nonperfused volume (NPV ratio. Safety was evaluated by recording of adverse events (AEs within 30 days’ follow-up. Results. All MR-HIFU treatments were successfully completed in an outpatient setting. The median NPV ratio was 0.56 (IQR [0.27–0.72]. Immediately after treatment, two patients experienced coldness related discomfort which resolved at the same day. No serious (device-related AEs were reported. Specifically, no skin burns, cold injuries, or subcutaneous edema were observed. Conclusion. This study showed that it is safe and technically feasible to complete a volumetric MR-HIFU ablation with DISC. This technique may reduce the risk of thermal injury to the abdominal wall during MR-HIFU ablation of uterine fibroids. This trial is registered with NTR4189.

  14. Mitigation of abdominal scars during MR-guided focused ultrasound treatment of uterine leiomyomas with the use of an energy-blocking scar patch.

    Science.gov (United States)

    Yoon, Sang-Wook; Seong, Seok Ju; Jung, Sang-Geun; Lee, Sun Young; Jun, Hye Sun; Lee, Jong Tae

    2011-12-01

    To assess the clinical potential of using an energy-blocking scar patch for magnetic resonance-guided focused ultrasound (MRgFUS) treatment of uterine leiomyomas in patients with abdominal scars. A prospective, nonrandomized, single-arm study was conducted in 20 patients (mean age, 41.1 y; range, 33-51 y) with symptomatic leiomyomas (mean volume, 170 cm(3); range, 10-689 cm(3)) and abdominal scars (mean width, 3.3 mm; range, 1.5-8 mm; mean length, 131.6 mm; range, 86-178 mm) who underwent MRgFUS with an isolating patch covering the scar. Scar patches composed of US-blocking material were placed on patients' skin to cover the scar before treatment. Immediately after each treatment, contrast-enhanced T1-weighted MR images were acquired, and the nonperfused volume (NPV) ratio was measured to determine the technical success of the treatment. Patients were followed for 3 months after treatment for any procedure-related adverse events. All treatments were completed with no technical problems. No serious adverse events were reported during treatments and during 3 months of follow-up. The mean NPV ratio was 53.5% ± 21%. The scar patch provides an effective treatment option for patients with uterine leiomyomas and scars in the beam path, who were previously excluded from MRgFUS treatment as a result of an increased risk of skin burns. Copyright © 2011 SIR. Published by Elsevier Inc. All rights reserved.

  15. MRI-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis low back pain - case series of an innovative new technique

    Energy Technology Data Exchange (ETDEWEB)

    Weeks, Evan M.; Platt, Michael W. [St Mary' s Hospital, Imperial College Healthcare NHS Trust, Department of Anaesthesia and Pain Medicine, London (United Kingdom); Gedroyc, Wladyslaw [St Mary' s Hospital, Imperial College Healthcare NHS Trust, Department of Radiology, London (United Kingdom)

    2012-12-15

    To evaluate the safety and efficacy of magnetic resonance-guided focused ultrasound (MRgFUS) to treat facet joint osteoarthritis pain. Patients with a positive response to facet joint interventions were recruited from Pain and Spinal Clinics. Treatments were performed at the levels of pain according to symptomatology, previous invasive treatment and MRI grading of facet joint osteoarthritis. Both safety and efficacy data were collected. Pain palliation was evaluated using a validated pain numerical rating scale (NRS), Oswestry disability questionnaire (ODQ), Brief Pain Inventory (BPI) and the EuroQol (EQ-5D) health state score Eighteen patients were treated. There were no major adverse events. At 6/12 we found a reduction in both the NRS (average/worst) pain scores (60.2 %/51.2 %). This was associated with 45.9 % improvement in the ODQ score and 61.9 % reduction in the BPI interference score. We observed an improvement in the EuroQol (EQ-5D) health state score based on UK coefficients of +0.379 (0.317 to 0.696). Our phase I observational pilot study has evaluated an innovative new technique that is both non-invasive and radiation free. It is the first description of this procedure in the literature. In all patients the technique was safe, free of complications, effective and well tolerated. (orig.)

  16. Perfusion volume correlates, percentage of involution, and clinical efficacy at diverse follow-up survey times after MR-guided focused ultrasound surgery in uterine fibroids: first report in a Mexican mestizo population

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco-Choque, Ana Luz; Fernandez-de Lara, Yeni; Vivas-Bonilla, Ingrid; Romero-Trejo, Cecilia [Medica Sur Clinic and Foundation, Magnetic Resonance Unit, Mexico City (Mexico); Villa, Antonio R. [UNAM, Division de Investigacion, Facultad de Medicina, Mexico City (Mexico); Roldan-Valadez, Ernesto [Medica Sur Clinic and Foundation, Magnetic Resonance Unit, Mexico City (Mexico); Medica Sur Clinic and Foundation, Coordination of Research and Innovation, Magnetic Resonance Unit, Mexico City (Mexico)

    2015-10-15

    To evaluate the clinical efficacy of magnetic resonance-guided focused ultrasound surgery in a Mexican mestizo population. This retrospective study included 159 women (mean age 37 ± 6.4 years, range 22-53 years) from 2008 to 2010. Two hundred sixty-eight symptomatic uterine fibroids were treated using MR-guided focused ultrasound surgery. Parameters included initial perfused volume, final perfused volume, non-perfused volume (NPV), and treated volume ratio (TVR). Follow-up up to 15 months assessed treatment efficacy and symptomatic relief. Non-parametric statistics and the Kaplan-Meier method were performed. T{sub 2}-weighted hypointense fibroids showed a frequency of 93.6 %; isointense and hyperintense fibroids had frequencies of 5.60 and 1.1 %. There was a negative correlation between NPV and age (r = -0.083, p = 0.307) and treatment time (r = -0.253, p = 0.001). Median TVR was 96.0 % in small fibroids and 76.5 % in large fibroids. Involution of 50 % and 80 % was achieved at months 6-7 and month 11, respectively. Relief of symptoms was significant (p < 0.05). Our data show that higher TVR attained immediately post-treatment of MRgFUS favours higher involution percentages at follow-up; however, careful patient selection and use of pretreatment imaging are important components for predicting success using MR-guided focused ultrasound surgery. (orig.)

  17. MRI-guided focused ultrasound robotic system for the treatment of bone cancer.

    Science.gov (United States)

    Menikou, Georgios; Yiallouras, Christos; Yiannakou, Marinos; Damianou, Christakis

    2017-03-01

    A novel MRI-conditional robot was developed that navigates a focused ultrasound (FUS) transducer. With this robotic system the transducer can access bones. The intended application is pain palliation from bone cancer using thermal ablation using FUS. The robotic system has four computer-controlled axes (three linear and one angular). The robotic system was manufactured using a digital manufacturing 3D printer, using acrylonitrile butadiene styrene (ABS) plastic. MRI-conditional optical encoders were used to accurately control the robotic system. The robotic system was successfully tested for MRI safety and compatibility, using fast-gradient pulse sequences and a liquid phantom. The robotic system has been tested for its functionality for creating discrete and multiple (overlapping) lesions in a gel phantom. An MRI-conditional FUS robotic system was developed that has the potential to create thermal lesions with the intention of treating bone cancer for the purpose of pain palliation. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  18. Focal therapy for localized unifocal and multifocal prostate cancer: A prospective development study using real time MR guided focused ultrasound

    Science.gov (United States)

    Napoli, A.; Caliolo, G.; Boni, F.; Anzidei, M.; Catalano, C.

    2017-03-01

    To assess safety and feasibility of non-invasive high intensity 3T MR guided focused ultrasound (MRgFUS) treatment of localized prostate cancer in an exploratory designed study. Men aged 45-80 years were eligible for this prospective study if they had low-risk localized prostate cancer (prostate specific antigen [PSA] ≤10 ng/mL, Gleason score ≤ 3 + 3), with no previous androgen deprivation or treatment for prostate cancer, and who could safely undergo multiparametric MRI (Discovery 750, GE; Gd-Bopta, Bracco) and have a spinal anesthetic. Patients underwent focal therapy using real time MR guided high intensity focused ultrasound (MRgFUS), delivered to all known cancer lesions, with a margin of normal tissue. Primary endpoints were adverse events (serious and otherwise) and urinary symptoms and erectile function assessed using patient questionnaires. 8 men were recruited between June 2011 and June 2012. After treatment, one man was admitted to hospital for acute urinary retention. Another patient had self-resolving, mild, intermittent dysuria (median duration 5.0 days). Urinary tract infection was not reported. Urinary debris occurred in 6 men (75%), with a median duration of 12 days. Median overall International Index of Erectile Function-15 (IIEF-15) scores were similar at baseline and at 6 to 12 months (p=0.060), as were median IIEF-15 scores for intercourse satisfaction (p=0.433), sexual desire (p=0.622), and overall satisfaction (p=0.256). There was an improvement in lower urinary tract symptoms, assessed by International Prostate Symptom Score (IPSS), between baseline and 6 to 12 months (p=0.026). All 8 men with no baseline urinary incontinence were leak-free and pad-free by 9 months. No histological evidence of cancer was identified in 7 of 8 men biopsied at 6 months (87,5%); overall, the entire population (8 patients) was free of clinically significant cancer and had no evidence of disease on multi-parametric MRI at 6 to 12 months. MR guided Focused

  19. RESONANCE

    Indian Academy of Sciences (India)

    Nuclear magnetic resonance (NMR) is a mani- festation of an intrinsic property of the nucleus, i.e. nuclear spin angular momen- tum. Spin angular momentum gives rise to magnetic moments. Thus, nuclei that pos- sess net magnetic moments behave like very small bar magnets. NMR spectroscopy in- volves the study of the ...

  20. Safety and Feasibility of Direct Magnetic Resonance Imaging-guided Transperineal Prostate Biopsy Using a Novel Magnetic Resonance Imaging-safe Robotic Device.

    Science.gov (United States)

    Ball, Mark W; Ross, Ashley E; Ghabili, Kamyar; Kim, Chunwoo; Jun, Changhan; Petrisor, Doru; Pan, Li; Epstein, Jonathan I; Macura, Katarzyna J; Stoianovici, Dan S; Allaf, Mohamad E

    2017-11-01

    To evaluate safety and feasibility in a first-in-human trial of a direct magnetic resonance imaging (MRI)-guided prostate biopsy using a novel robotic device. MrBot is an MRI-safe robotic device constructed entirely with nonconductive, nonmetallic, and nonmagnetic materials and developed by our group. A safety and feasibility clinical trial was designed to assess the safety and feasibility of a direct MRI-guided biopsy with MrBot and to determine its targeting accuracy. Men with elevated prostate-specific antigen levels, prior negative prostate biopsies, and cancer-suspicious regions (CSRs) on MRI were enrolled in the study. Biopsies targeting CSRs, in addition to sextant locations, were performed. Five men underwent biopsy with MrBot. Two men required Foley catheter insertion after the procedure, with no other complications or adverse events. Even though this was not a study designed to detect prostate cancer, biopsies confirmed the presence of a clinically significant cancer in 2 patients. On a total of 30 biopsy sites, the robot achieved an MRI-based targeting accuracy of 2.55 mm and a precision of 1.59 mm normal to the needle, with no trajectory corrections and no unsuccessful attempts to target a site. Robot-assisted MRI-guided prostate biopsy appears safe and feasible. This study confirms that a clinically significant prostate cancer (≥5-mm radius, 0.5 cm 3 ) depicted in MRI may be accurately targeted. Direct confirmation of needle placement in the CSR may present an advantage over fusion-based technology and gives more confidence in a negative biopsy result. Additional study is warranted to evaluate the efficacy of this approach. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Magnetic Resonance Imaging-Transrectal Ultrasound Guided Fusion Biopsy to Detect Progression in Patients with Existing Lesions on Active Surveillance for Low and Intermediate Risk Prostate Cancer.

    Science.gov (United States)

    Frye, Thomas P; George, Arvin K; Kilchevsky, Amichai; Maruf, Mahir; Siddiqui, M Minhaj; Kongnyuy, Michael; Muthigi, Akhil; Han, Hui; Parnes, Howard L; Merino, Maria; Choyke, Peter L; Turkbey, Baris; Wood, Brad; Pinto, Peter A

    2017-03-01

    Active surveillance is an established option for men with low risk prostate cancer. Multiparametric magnetic resonance imaging with magnetic resonance imaging-transrectal ultrasound fusion guided biopsy may better identify patients for active surveillance compared to systematic 12-core biopsy due to improved risk stratification. To our knowledge the performance of multiparametric magnetic resonance imaging in following men on active surveillance with visible lesions is unknown. We evaluated multiparametric magnetic resonance imaging and magnetic resonance imaging-transrectal ultrasound fusion guided biopsy to monitor men on active surveillance. This retrospective review included men from 2007 to 2015 with prostate cancer on active surveillance in whom magnetic resonance imaging visible lesions were monitored by multiparametric magnetic resonance imaging and fusion guided biopsy. Progression was defined by ISUP (International Society of Urological Pathology) grade group 1 to 2 and ISUP grade group 2 to 3. Significance was considered at p ≤0.05. A total of 166 patients on active surveillance with 2 or more fusion guided biopsies were included in analysis. Mean followup was 25.5 months. Of the patients 29.5% had pathological progression. Targeted biopsy alone identified 44.9% of patients who progressed compared to 30.6% identified by systematic 12-core biopsy alone (p = 0.03). Fusion guided biopsy detected 26% more cases of pathological progression on surveillance biopsy compared to systematic 12-core biopsy. Progression on multiparametric magnetic resonance imaging was the sole predictor of pathological progression at surveillance biopsy (p = 0.013). Multiparametric magnetic resonance imaging progression in the entire cohort had 81% negative predictive value, 35% positive predictive value, 77.6% sensitivity and 40.5% specificity in detecting pathological progression. Multiparametric magnetic resonance imaging progression predicts the risk of pathological

  2. Combined passive acoustic mapping and magnetic resonance thermometry for monitoring phase-shift nanoemulsion enhanced focused ultrasound therapy

    Science.gov (United States)

    Crake, Calum; Meral, F. Can; Burgess, Mark T.; Papademetriou, Iason T.; McDannold, Nathan J.; Porter, Tyrone M.

    2017-08-01

    Focused ultrasound (FUS) has the potential to enable precise, image-guided noninvasive surgery for the treatment of cancer in which tumors are identified and destroyed in a single integrated procedure. However, success of the method in highly vascular organs has been limited due to heat losses to perfusion, requiring development of techniques to locally enhance energy absorption and heating. In addition, FUS procedures are conventionally monitored using MRI, which provides excellent anatomical images and can map temperature, but is not capable of capturing the full gamut of available data such as the acoustic emissions generated during this inherently acoustically-driven procedure. Here, we employed phase-shift nanoemulsions (PSNE) embedded in tissue phantoms to promote cavitation and hence temperature rise induced by FUS. In addition, we incorporated passive acoustic mapping (PAM) alongside simultaneous MR thermometry in order to visualize both acoustic emissions and temperature rise, within the bore of a full scale clinical MRI scanner. Focal cavitation of PSNE could be resolved using PAM and resulted in accelerated heating and increased the maximum elevated temperature measured via MR thermometry compared to experiments without nanoemulsions. Over time, the simultaneously acquired acoustic and temperature maps show translation of the focus of activity towards the FUS transducer, and the magnitude of the increase in cavitation and focal shift both increased with nanoemulsion concentration. PAM results were well correlated with MRI thermometry and demonstrated greater sensitivity, with the ability to detect cavitation before enhanced heating was observed. The results suggest that PSNE could be beneficial for enhancement of thermal focused ultrasound therapies and that PAM could be a critical tool for monitoring this process.

  3. Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU): Pilot Study in a Swine Model.

    Science.gov (United States)

    Huisman, Merel; Staruch, Robert M; Ladouceur-Wodzak, Michelle; van den Bosch, Maurice A; Burns, Dennis K; Chhabra, Avneesh; Chopra, Rajiv

    2015-01-01

    Ultrasound (US)-guided high intensity focused ultrasound (HIFU) has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic resonance (MR)-imaging guidance may overcome these limitations and MR-guided HIFU (MR-HIFU) has been used successfully for other clinical indications. The primary purpose of this study was to evaluate the feasibility of utilizing 3D MR neurography to identify and guide ablation of peripheral nerves using a clinical MR-HIFU system. Volumetric MR-HIFU was used to induce lesions in the peripheral nerves of the lower limbs in three pigs. Diffusion-prep MR neurography and T1-weighted images were utilized to identify the target, plan treatment and immediate post-treatment evaluation. For each treatment, one 8 or 12 mm diameter treatment cell was used (sonication duration 20 s and 36 s, power 160-300 W). Peripheral nerves were extracted HIFU. Diffusion-prep 3D MR neurography has potential for guiding therapy procedures where either nerve targeting or avoidance is desired, and may also have potential for post-treatment verification of thermal lesions without contrast injection.

  4. Magnetic resonance imaging guided reirradiation of recurrent and second primary head and neck cancer

    Directory of Open Access Journals (Sweden)

    Allen M. Chen, MD

    2017-04-01

    Conclusions: Our preliminary findings show that reirradiation with MRI guided radiation therapy results in effective disease control with relatively low morbidity for patients with recurrent and second primary cancers of the head and neck. The superior soft tissue resolution of the MRI scans that were used for planning and delivery has the potential to improve the therapeutic ratio.

  5. Review of the role of cardiovascular magnetic resonance in congenital heart disease, with a focus on right ventricle assessment.

    Science.gov (United States)

    Bonello, Beatrice; Kilner, Philip J

    2012-11-01

    Adult patients with congenital heart disease (ACHD) represent a growing population due to progress in management. Surgical procedures generally fall short of restoring entirely normal anatomical and functional relations. Further procedures can be needed and lifelong follow-up is required. The right ventricle (RV) plays an important role in congenital heart disease and cardiac magnetic resonance (CMR) imaging has become the imaging method of choice for its assessment. CMR can provide relatively accurate measurements of RV volume and function, and arterial flow, with additional anatomical information provided by three-dimensional contrast angiography and late gadolinium imaging of fibrosis. Here we focus our review on three categories of ACHD in which evaluation of the RV is important: repaired tetralogy of Fallot, the systemic RV and Ebstein anomaly. We demonstrate how CMR contributes to decision-making regarding the types and timings of interventions. A dedicated CMR service should be regarded as a necessary facility of a centre specializing in the care of ACHD patients. Copyright © 2012. Published by Elsevier Masson SAS.

  6. Multivariate data analysis and machine learning in Alzheimer's disease with a focus on structural magnetic resonance imaging.

    Science.gov (United States)

    Falahati, Farshad; Westman, Eric; Simmons, Andrew

    2014-01-01

    Machine learning algorithms and multivariate data analysis methods have been widely utilized in the field of Alzheimer's disease (AD) research in recent years. Advances in medical imaging and medical image analysis have provided a means to generate and extract valuable neuroimaging information. Automatic classification techniques provide tools to analyze this information and observe inherent disease-related patterns in the data. In particular, these classifiers have been used to discriminate AD patients from healthy control subjects and to predict conversion from mild cognitive impairment to AD. In this paper, recent studies are reviewed that have used machine learning and multivariate analysis in the field of AD research. The main focus is on studies that used structural magnetic resonance imaging (MRI), but studies that included positron emission tomography and cerebrospinal fluid biomarkers in addition to MRI are also considered. A wide variety of materials and methods has been employed in different studies, resulting in a range of different outcomes. Influential factors such as classifiers, feature extraction algorithms, feature selection methods, validation approaches, and cohort properties are reviewed, as well as key MRI-based and multi-modal based studies. Current and future trends are discussed.

  7. MR-guided focused ultrasound: enhancement of intratumoral uptake of [{sup 3}H]-docetaxel in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Chen Lili; Mu Zhaomei; Hachem, Paul; Ma, C-M; Wallentine, Annie; Pollack, Alan, E-mail: lili.Chen@fccc.ed [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111 (United States)

    2010-12-21

    The purpose of this study is to quantify the enhancement of [{sup 3}H]-docetaxel in implanted prostate tumors treated with MR-guided pulsed focused ultrasound (MRgFUS). Human prostate cancer, LNCaP cells in 25 {mu}l, were implanted into the prostates of male nude mice. The tumor growth was directly monitored on MRI. When the tumor reached a designated size, MRgFUS treatment was performed using a focused ultrasound treatment system (InSightec ExAblate 2000) with a 1.5 T GE MR scanner. The tumor-bearing animals were randomly divided into three groups: group 1, MRgFUS treatment + [{sup 3}H]-docetaxel; group 2, [{sup 3}H]-docetaxel only and group 3, as a control. Animals in group 1 were treated with MRgFUS non-invasively. Immediately after the treatment, the animals received a single dose of tail vein injection of docetaxel at 15 mg kg{sup -1} mixed with [{sup 3}H]-docetaxel at 50 uCi kg{sup -1} in a total volume of 150 {mu}l. Animals in group 2 were treated the same as in group one, however without MRgFUS treatment. Animals in group 3 were treated as a control. Animals were sacrificed 30 min after i.v. injections regardless of whether or not they received focused ultrasound. Tumors were removed and processed. The radioactivity of [{sup 3}H]-docetaxel in the tumor tissue was quantitatively measured by a liquid scintillation counter. Our study showed that all animals tolerated the MRgFUS treatment well. Our data showed increased {sup 3}H-docetaxel concentration in the tumor in the MRgFUS-treated group (1079 {+-} 132 cmp/75 mg) versus those without MRgFUS treatment (524 {+-} 201 cmp/75 mg) with P = 0.037.

  8. Ultrasound-guided tissue fractionation by high intensity focused ultrasound in an in vivo porcine liver model.

    Science.gov (United States)

    Khokhlova, Tatiana D; Wang, Yak-Nam; Simon, Julianna C; Cunitz, Bryan W; Starr, Frank; Paun, Marla; Crum, Lawrence A; Bailey, Michael R; Khokhlova, Vera A

    2014-06-03

    The clinical use of high intensity focused ultrasound (HIFU) therapy for noninvasive tissue ablation has been recently gaining momentum. In HIFU, ultrasound energy from an extracorporeal source is focused within the body to ablate tissue at the focus while leaving the surrounding organs and tissues unaffected. Most HIFU therapies are designed to use heating effects resulting from the absorption of ultrasound by tissue to create a thermally coagulated treatment volume. Although this approach is often successful, it has its limitations, such as the heat sink effect caused by the presence of a large blood vessel near the treatment area or heating of the ribs in the transcostal applications. HIFU-induced bubbles provide an alternative means to destroy the target tissue by mechanical disruption or, at its extreme, local fractionation of tissue within the focal region. Here, we demonstrate the feasibility of a recently developed approach to HIFU-induced ultrasound-guided tissue fractionation in an in vivo pig model. In this approach, termed boiling histotripsy, a millimeter-sized boiling bubble is generated by ultrasound and further interacts with the ultrasound field to fractionate porcine liver tissue into subcellular debris without inducing further thermal effects. Tissue selectivity, demonstrated by boiling histotripsy, allows for the treatment of tissue immediately adjacent to major blood vessels and other connective tissue structures. Furthermore, boiling histotripsy would benefit the clinical applications, in which it is important to accelerate resorption or passage of the ablated tissue volume, diminish pressure on the surrounding organs that causes discomfort, or insert openings between tissues.

  9. A case-control study of high-intensity focused ultrasound combined with sonographically guided intratumoral ethanol injection in the treatment of uterine fibroids.

    Science.gov (United States)

    Yang, Zhiwei; Zhang, Yibin; Zhang, Rui; Zhang, Hongyu; Ma, Jijiang; Chen, Jinyu; Wang, Jinfeng; Jiang, Kaihui; Mu, Danmei; Yu, Yingjiao; Yang, Haishan

    2014-04-01

    The purpose of this study was to explore the feasibility of high-intensity focused ultrasound combined with sonographically guided intratumoral ethanol injection in the treatment of uterine fibroids and to compare its therapeutic effects and potential side effects with those of simple high-intensity focused ultrasound treatment. Forty patients with uterine fibroids from the Department of Ultrasonography in our hospital were randomly divided into 2 groups of the same size: group H, which only underwent high-intensity focused ultrasound treatment; and group H + A, which underwent sonographically guided intratumoral ethanol injection therapy first and then high-intensity focused ultrasound treatment the following day. The treatment times, treatment doses, pain scores, side effects, and therapeutic effect rates of the groups were then recorded and compared. Both the treatment time and dose of group H + A were significantly less than those of group H, and the differences were statistically significant (P focused ultrasound combined with sonographically guided intratumoral ethanol injection requires less treatment time and a lower dose than simple high-intensity focused ultrasound treatment and significantly reduces the pain and side effects commonly experienced by patients. High-intensity focused ultrasound combined with sonographically guided intratumoral ethanol injection is a feasible, safe, and more effective way to treat patients with uterine fibroids.

  10. Ultrasound/Magnetic Resonance Image Fusion Guided Lumbosacral Plexus Block – A Clinical Study

    DEFF Research Database (Denmark)

    Strid, JM; Pedersen, Erik Morre; Søballe, Kjeld

    2014-01-01

    in a double-blinded randomized controlled trial with crossover design. MR datasets will be acquired and uploaded in an advanced US system (Epiq7, Phillips, Amsterdam, Netherlands). All volunteers will receive SSPS blocks with lidocaine added gadolinium contrast guided by US/MR image fusion and by US one week......Background and aims Ultrasound (US) guided lumbosacral plexus block (Supra Sacral Parallel Shift [SSPS]) offers an alternative to general anaesthesia and perioperative analgesia for hip surgery.1 The complex anatomy of the lumbosacral region hampers the accuracy of the block, but it may be improved...... apart. The block of the L2-S1 nerves, the plasma lidocaine, and the anatomical distribution of lidocaine will be assessed with neurological mapping, pharmacokinetic assays, and MR visualisation and compared. We are awaiting the final ethical approval of the study. Results On going study. Conclusions...

  11. Numerical study on enhanced absorption of nanospaced MoS2 multilayers via guided-mode resonance

    Science.gov (United States)

    Shen, Kesheng; Lu, Hai; Zhang, Jun; Xia, Shiqiang; Kang, Xiubao; Dong, Chao; Xiong, Zonggang; Zhang, Xianzhou

    2017-10-01

    The enhancement of optical absorption in cascaded monolayer MoS2 separated alternately by high-index slab and low-index slab is investigated numerically according to well-known equations. It is found that the large tangential wave vector can result in optical absorption enhancement for p-polarized illumination, due to the large field enhancement at the interface of high/low-index mediums, associated with the excitation of guided-wave resonance modes. The optical absorption around the excitonic states of the monolayer MoS2 can be greatly enhanced up to ~50% for such structures without the assistance of any other lossy materials, such as plasmonic materials. And the absorbance will be close to 100% when the optical properties of surrounding is unsymmetrical. This property is particularly beneficial for harvesting light in devices based on atomically thin MoS2 while preserving the innate direct band gap property of monolayer MoS2.

  12. Manganese (II) Chelate Functionalized Copper Sulfide Nanoparticles for Efficient Magnetic Resonance/Photoacoustic Dual-Modal Imaging Guided Photothermal Therapy.

    Science.gov (United States)

    Liu, Renfa; Jing, Lijia; Peng, Dong; Li, Yong; Tian, Jie; Dai, Zhifei

    2015-01-01

    The integration of diagnostic and therapeutic functionalities into one nanoplatform shows great promise in cancer therapy. In this research, manganese (II) chelate functionalized copper sulfide nanoparticles were successfully prepared using a facile hydrothermal method. The obtained ultrasmall nanoparticles exhibit excellent photothermal effect and photoaoustic activity. Besides, the high loading content of Mn(II) chelates makes the nanoparticles attractive T1 contrast agent in magnetic resonance imaging (MRI). In vivo photoacoustic imaging (PAI) results showed that the nanoparticles could be efficiently accumulated in tumor site in 24 h after systematic administration, which was further validated by MRI tests. The subsequent photothermal therapy of cancer in vivo was achieved without inducing any observed side effects. Therefore, the copper sulfide nanoparticles functionalized with Mn(II) chelate hold great promise as a theranostic nanomedicine for MR/PA dual-modal imaging guided photothermal therapy of cancer.

  13. Manganese (II) Chelate Functionalized Copper Sulfide Nanoparticles for Efficient Magnetic Resonance/Photoacoustic Dual-Modal Imaging Guided Photothermal Therapy

    Science.gov (United States)

    Liu, Renfa; Jing, Lijia; Peng, Dong; Li, Yong; Tian, Jie; Dai, Zhifei

    2015-01-01

    The integration of diagnostic and therapeutic functionalities into one nanoplatform shows great promise in cancer therapy. In this research, manganese (II) chelate functionalized copper sulfide nanoparticles were successfully prepared using a facile hydrothermal method. The obtained ultrasmall nanoparticles exhibit excellent photothermal effect and photoaoustic activity. Besides, the high loading content of Mn(II) chelates makes the nanoparticles attractive T1 contrast agent in magnetic resonance imaging (MRI). In vivo photoacoustic imaging (PAI) results showed that the nanoparticles could be efficiently accumulated in tumor site in 24 h after systematic administration, which was further validated by MRI tests. The subsequent photothermal therapy of cancer in vivo was achieved without inducing any observed side effects. Therefore, the copper sulfide nanoparticles functionalized with Mn(II) chelate hold great promise as a theranostic nanomedicine for MR/PA dual-modal imaging guided photothermal therapy of cancer. PMID:26284144

  14. Magnetic resonance imaging-guided attenuation and scatter corrections in three-dimensional brain positron emission tomography

    CERN Document Server

    Zaidi, H; Slosman, D O

    2003-01-01

    Reliable attenuation correction represents an essential component of the long chain of modules required for the reconstruction of artifact-free, quantitative brain positron emission tomography (PET) images. In this work we demonstrate the proof of principle of segmented magnetic resonance imaging (MRI)-guided attenuation and scatter corrections in 3D brain PET. We have developed a method for attenuation correction based on registered T1-weighted MRI, eliminating the need of an additional transmission (TX) scan. The MR images were realigned to preliminary reconstructions of PET data using an automatic algorithm and then segmented by means of a fuzzy clustering technique which identifies tissues of significantly different density and composition. The voxels belonging to different regions were classified into air, skull, brain tissue and nasal sinuses. These voxels were then assigned theoretical tissue-dependent attenuation coefficients as reported in the ICRU 44 report followed by Gaussian smoothing and additio...

  15. Phase accumulation tracking algorithm for effective index retrieval of fishnet metamaterials and other resonant guided wave networks

    Science.gov (United States)

    Feigenbaum, Eyal; Hiszpanski, Anna M.

    2017-07-01

    A phase accumulation tracking (PAT) algorithm is proposed and demonstrated for the retrieval of the effective index of fishnet metamaterials (FMMs) in order to avoid the multi-branch uncertainty problem. This algorithm tracks the phase and amplitude of the dominant propagation mode across the FMM slab. The suggested PAT algorithm applies to resonant guided wave networks having only one mode that carries the light between the two slab ends, where the FMM is one example of this metamaterials sub-class. The effective index is a net effect of positive and negative accumulated phase in the alternating FMM metal and dielectric layers, with a negative effective index occurring when negative phase accumulation dominates.

  16. Outcome of uterine artery embolization versus MR-guided high-intensity focused ultrasound treatment for uterine fibroids: Long-term results

    Energy Technology Data Exchange (ETDEWEB)

    Froeling, V., E-mail: Vera.Froeling@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); Meckelburg, K., E-mail: Katrin.Meckelburg@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); Schreiter, N.F., E-mail: Nils.Schreiter@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); Scheurig-Muenkler, C., E-mail: Christian.Scheurig@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); Kamp, J., E-mail: Julia.Kamp@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); Maurer, M.H., E-mail: Martin.Maurer@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); Beck, A., E-mail: Alexander.Beck@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); Hamm, B., E-mail: Bernd.Hamm@charite.de [Department of Radiology, Charité – Universitätsmedizin Berlin, Campus Virchow, Augustenburger Platz 1, 13353 Berlin (Germany); and others

    2013-12-01

    Objectives: To compare the long-term outcome after uterine artery embolization (UAE) versus magnetic resonance-guided high-intensity focused ultrasound (MR-g HIFU) for symptomatic uterine fibroids. Methods: Seventy-seven women (median age, 39.3 years; range, 29.2–52.2 years) with symptomatic uterine fibroids, equally eligible for UAE and MR-g HIFU based on our exclusion criteria underwent treatment (UAE, N = 41; MR-g HIFU, N = 36) from 2002 to 2009 at our institution. Symptom severity (SS) and total health-related quality of life (Total HRQoL) scores were assessed by the uterine fibroid symptom and quality of life (UFS-QoL) questionnaire before treatment and at long-term follow-up after UAE (median 61.9 months) and after MR-g HIFU (median: 60.7 months). Re-intervention rates were assessed for each therapy and compared. Results: Re-intervention was significantly lower after UAE (12.2%) than after MR-g HIFU (66.7%) at long-term follow-up (p < 0.001). After UAE changes in SS (50 pre-treatment vs. 6.3 post-treatment) and Total HRQoL (57.8 pre-treatment vs. 100 post-treatment) were significantly better than changes in SS (42.2 pre-treatment vs. 26.6 post-treatment) and Total HRQoL score (66.4 pre-treatment vs. 87.9 post-treatment) after MR-g HIFU (p = 0.019 and 0.049 respectively). Conclusions: Improvement of SS and Total HRQoL scores was significantly better after UAE resulting in a significant lower re-intervention rate compared to MR-g HIFU.

  17. Initial investigation of a novel noninvasive weight loss therapy using MRI-Guided high intensity focused ultrasound (MR-HIFU) of visceral fat.

    Science.gov (United States)

    Winter, Patrick M; Lanier, Matthew; Partanen, Ari; Dumoulin, Charles

    2016-07-01

    MRI-guided high intensity focused ultrasound (MR-HIFU) allows noninvasive heating of deep tissues. Specifically targeting visceral fat deposits with MR-HIFU could offer an effective therapy for reversing the development of obesity, diabetes, and metabolic syndrome. Overweight rats received either MR-HIFU of visceral fat, sham treatment, no treatment, or ex vivo temperature calibration. Conventional MR thermometry methods are not effective in fat tissue. Therefore, the T2 of fat was used to estimate heating in adipose tissue. HIFU treated rats lost 7.5% of their body weight 10 days after HIFU, compared with 1.9% weight loss in sham animals (P = 0.008) and 1.3% weight increase in untreated animals (P = 0.004). Additionally, the abdominal fat volume in treated animals decreased by 8.2 mL 7 days after treatment (P = 0.002). The T2 of fat at 1.5 Tesla increased by 3.3 ms per °C. The fat T2 was 103.3 ms before HIFU, but increased to 128.7 ms (P = 0.0005) after HIFU at 70 watts for 16 s and to 131.9 ms (P = 0.0005) after HIFU at 100 watts for 16 s. These experiments demonstrate that MR-HIFU of visceral fat could provide a safe, effective, and noninvasive weight loss therapy for combating obesity and the subsequent medical complications. Magn Reson Med 76:282-289, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  18. Restoring Neurological Physiology: The Innovative Role of High-Energy MR-Guided Focused Ultrasound (HIMRgFUS). Preliminary Data from a New Method of Lesioning Surgery.

    Science.gov (United States)

    Giugno, Antonella; Maugeri, Rosario; Graziano, Francesca; Gagliardo, Cesare; Franzini, Angelo; Catalano, Carlo; Midiri, Massimo; Iacopino, Domenico Gerardo

    2017-01-01

    Tremor is a disabling condition, common to several neurodegenerative diseases. Lesioning procedures and deep brain stimulation, respectively, of the ventralis intermedius nucleus for intentional tremor, and of the subthalamic nucleus for parkinsonian resting tremor, have been introduced in clinical practice for patients refractory to medical treatment. The combination of high-energy focused ultrasound (HIFUS) with sophisticated magnetic resonance (MR) instrumentation, together with accurate knowledge of the stereotactic brain coordinates, represents a revolution in neuromodulation. At the Neurosurgical Clinic and the Radiology Department of the University of Palermo,, two patients affected by severe and refractory forms of intentional tremor were treated by MRI-guided FUS (MRgFUS) with a unique 1.5 T MR scanner prototype that uses FUS. This apparatus is the only one of its type in the world." This is the first Italian experience, and the second in Europe, of treatment with MRI-gFUS for intentional tremor. But this is the very first experience in which a 1.5 T MRI apparatus was used. In both patients, the treatment completely abolished the tremor on the treated side, with results being excellent and stable after 7 and 5 months, respectively; no side effects were encountered. MRgFUS, recently introduced in clinical practice, and widely used at several clinical centers, has been shown to be a valid therapeutic alternative in the treatment of tremor in several neurodegenerative diseases. It is virtually safe, noninvasive, and very efficacious. We report this technique in which a 1.5 T MR scanner was used. Further investigations with long-term follow up and larger clinical series are needed.

  19. Three-dimensional quantitative assessment of lesion response to MR-guided high-intensity focused ultrasound treatment of uterine fibroids.

    Science.gov (United States)

    Savic, Lynn J; Lin, Ming De; Duran, Rafael; Schernthaner, Rüdiger E; Hamm, Bernd; Geschwind, Jean-François; Hong, Kelvin; Chapiro, Julius

    2015-09-01

    To investigate the response after magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) treatment of uterine fibroids (UF) using a three-dimensional (3D) quantification of total and enhancing lesion volume (TLV and ELV, respectively) on contrast-enhanced MRI (ceMRI) scans. In a total of 24 patients, ceMRI scans were obtained at baseline and 24 hours, and 6, 12, and 24 months after MRgHIFU treatment. The dominant lesion was assessed using a semiautomatic quantitative 3D segmentation technique. Agreement between software-assisted and manual measurements was then analyzed using a linear regression model. Patients were classified as responders (R) or nonresponders (NR) on the basis of their symptom report after 6 months. Statistical analysis included the paired t-test and Mann-Whitney test. Preprocedurally, the median TLV and ELV were 263.74 cm(3) (30.45-689.56 cm(3)) and 210.13 cm(3) (14.43-689.53 cm(3)), respectively. The 6-month follow-up demonstrated a reduction of TLV in 21 patients (87.5%) with a median TLV of 171.7 cm(3) (8.5-791.2 cm(3); P baseline (P fibroid volumes (R(2) = .889 and .917) but greater discrepancy for enhancement calculations (R(2) = .659 and .419) at baseline and 6 months. No significant differences in TLV or ELV were observed between clinical R (n = 15) and NR (n = 3). The 3D assessment has proven feasible and accurate in the quantification of fibroid response to MRgHIFU. Contrary to ELV, changes in TLV may be representative of the clinical outcome. Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.

  20. SU-E-J-04: Integration of Interstitial High Intensity Therapeutic Ultrasound Applicators On a Clinical MRI-Guided High Intensity Focused Ultrasound Treatment Planning Software Platform

    Energy Technology Data Exchange (ETDEWEB)

    Ellens, N [Johns Hopkins University, Baltimore, Maryland (United States); Partanen, A [Philips Healthcare, Andover, Massachusetts (United States); Ghoshal, G; Burdette, E [Acoustic MedSystems Inc., Savoy, IL (United States); Farahani, K [National Cancer Institute, Bethesda, MD (United States)

    2015-06-15

    Purpose: Interstitial high intensity therapeutic ultrasound (HITU) applicators can be used to ablate tissue percutaneously, allowing for minimally-invasive treatment without ionizing radiation [1,2]. The purpose of this study was to evaluate the feasibility and usability of combining multielement interstitial HITU applicators with a clinical magnetic resonance imaging (MRI)-guided focused ultrasound software platform. Methods: The Sonalleve software platform (Philips Healthcare, Vantaa, Finland) combines anatomical MRI for target selection and multi-planar MRI thermometry to provide real-time temperature information. The MRI-compatible interstitial US applicators (Acoustic MedSystems, Savoy, IL, USA) had 1–4 cylindrical US elements, each 1 cm long with either 180° or 360° of active surface. Each applicator (4 Fr diameter, enclosed within a 13 Fr flexible catheter) was inserted into a tissue-mimicking agar-silica phantom. Degassed water was circulated around the transducers for cooling and coupling. Based on the location of the applicator, a virtual transducer overlay was added to the software to assist targeting and to allow automatic thermometry slice placement. The phantom was sonicated at 7 MHz for 5 minutes with 6–8 W of acoustic power for each element. MR thermometry data were collected during and after sonication. Results: Preliminary testing indicated that the applicator location could be identified in the planning images and the transducer locations predicted within 1 mm accuracy using the overlay. Ablation zones (thermal dose ≥ 240 CEM43) for 2 active, adjacent US elements ranged from 18 mm × 24 mm (width × length) to 25 mm × 25 mm for the 6 W and 8 W sonications, respectively. Conclusion: The combination of interstitial HITU applicators and this software platform holds promise for novel approaches in minimally-invasive MRI-guided therapy, especially when bony structures or air-filled cavities may preclude extracorporeal HIFU.[1] Diederich et al

  1. Magnetic resonance imaging guided transatrial electrophysiological studies in swine using active catheter tracking - experience with 14 cases

    Energy Technology Data Exchange (ETDEWEB)

    Grothoff, Matthias; Gutberlet, Matthias [University of Leipzig - Heart Center, Department of Radiology, Leipzig (Germany); Hindricks, Gerhard; Sommer, Philipp; Hilbert, Sebastian [University of Leipzig - Heart Center, Department of Electrophysiology, Leipzig (Germany); Fleiter, Christian [Helios Klinikum Berlin-Buch, Department of Orthopaedic Surgery, Berlin (Germany); Schnackenburg, Bernhard [Philips Healthcare, Hamburg (Germany); Weiss, Steffen; Krueger, Sascha [Philips Innovative Technologies, Hamburg (Germany); Piorkowski, Christopher; Gaspar, Thomas [University of Dresden - Heart Center, Department of Electrophysiology, Dresden (Germany); Wedan, Steve; Lloyd, Thomas [Imricor Medical Systems, Burnsville, MN (United States)

    2017-05-15

    To evaluate the feasibility of performing comprehensive Cardiac Magnetic resonance (CMR) guided electrophysiological (EP) interventions in a porcine model encompassing left atrial access. After introduction of two femoral sheaths 14 swine (41 ± 3.6 kg) were transferred to a 1.5 T MR scanner. A three-dimensional whole-heart sequence was acquired followed by segmentation and the visualization of all heart chambers using an image-guidance platform. Two MR conditional catheters were inserted. The interventional protocol consisted of intubation of the coronary sinus, activation mapping, transseptal left atrial access (n = 4), generation of ablation lesions and eventually ablation of the atrioventricular (AV) node. For visualization of the catheter tip active tracking was used. Catheter positions were confirmed by passive real-time imaging. Total procedure time was 169 ± 51 minutes. The protocol could be completed in 12 swine. Two swine died from AV-ablation induced ventricular fibrillation. Catheters could be visualized and navigated under active tracking almost exclusively. The position of the catheter tips as visualized by active tracking could reliably be confirmed with passive catheter imaging. Comprehensive CMR-guided EP interventions including left atrial access are feasible in swine using active catheter tracking. (orig.)

  2. MR-guided focused ultrasound. Current and future applications; MR-gesteuerter fokussierter Ultraschall. Aktuelle und potenzielle Indikationen

    Energy Technology Data Exchange (ETDEWEB)

    Trumm, C.G.; Peller, M.; Clevert, D.A.; Stahl, R.; Reiser, M. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen-Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Napoli, A. [Sapienza Universitaet Rom, Abteilung fuer Radiologie (Department of Radiological Sciences), MRgFUS and Cardiovascular Imaging Unit, Rom (Italy); Matzko, M. [Klinikum Dachau, Abteilung fuer diagnostische und interventionelle Radiologie, Dachau (Germany)

    2013-03-15

    High-intensity focused ultrasound (synonyms FUS and HIFU) under magnetic resonance imaging (MRI) guidance (synonyms MRgFUS and MR-HIFU) is a completely non-invasive technology for accurate thermal ablation of a target tissue while neighboring tissues and organs are preserved. The combination of FUS with MRI for planning, (near) real-time monitoring and outcome assessment of treatment markedly enhances the safety of the procedure. The MRgFUS procedure is clinically established in particular for the treatment of symptomatic uterine fibroids, followed by palliative ablation of painful bone metastases. Furthermore, promising results have been shown for the treatment of adenomyosis, malignant tumors of the prostate, breast and liver and for various intracranial applications, such as thermal ablation of brain tumors, functional neurosurgery and transient disruption of the blood-brain barrier. (orig.) [German] MRT-gesteuerter hochintensiver fokussierter Ultraschall (MRgFUS bzw. MR-HIFU) ist ein nichtinvasives Verfahren zur praezisen Thermoablation eines Zielgewebes. Bei dieser Methode werden benachbarte Gewebe und Organe geschont. Die Kombination des fokussierten Ultraschalls (FUS) mit der MRT zwecks Planung und Monitoring (nahezu) in Echtzeit sowie zur Erfolgskontrolle von Behandlungen traegt wesentlich zur Sicherheit dieser Methode bei. MRgFUS ist klinisch v. a. zur Behandlung von symptomatischen Uterusmyomen etabliert, gefolgt von der palliativen Ablation von Knochenmetastasen. Weitere vielversprechende Anwendungsgebiete des MRgFUS sind die Adenomyose des Uterus, die Behandlung von Prostata-, Mamma- und Lebertumoren sowie der intrakranielle Einsatz. (orig.)

  3. Low-cost fiber optic hydrogen gas detector using guided-wave surface-plasmon resonance in chemochromic thin films

    Science.gov (United States)

    Benson, David K.; Tracy, C. Ed; Hishmeh, Gary A.; Ciszek, Paul E.; Lee, Se-Hee; Haberman, D. P.

    1999-01-01

    Low-cost, hydrogen-gas-leak detectors are needed for many hydrogen applications, such as hydrogen-fueled vehicles where several detectors may be required in different locations on each vehicle. A fiber-optic leak detector could be inherently safer than conventional detectors, because it would remove all detector electronics from the vicinity of potential leaks. It would also provide freedom from electromagnetic interference, a serious problem in fuel- cell-powered electric vehicles. This paper describes the design of a fiber-optic, surface-plasmon-resonance hydrogen detector, and efforts to make it more sensitive, selective, and durable. Chemochromic materials, such as tungsten oxide and certain Lanthanide hydrides, can reversibly react with hydrogen in air while exhibiting significant changes in their optical properties. Thin films of these materials applied to a sensor at the nd of an optical fiber have been used to detect low concentrations of hydrogen gas in air. The coatings include a thin silver layer in which the surface plasmon is generated, a thin film of the chemochromic materials, and a catalytic layer of palladium that facilitates the reaction with hydrogen. The film thickness is chosen to produce a guided-surface plasmon wave along the interface between the silver and the chemichromic material. A dichroic beam-splitter separates the reflected spectrum into a portion near the resonance and a portion away from the resonance, and directs these two portions to two separate photodiodes. The electronic ratio of these two signals cancels most of the fiber transmission noise and provides a stable hydrogen signal.

  4. Theoretical predictions for spatially-focused heating of magnetic nanoparticles guided by magnetic particle imaging field gradients

    Energy Technology Data Exchange (ETDEWEB)

    Dhavalikar, Rohan [Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL 32611 (United States); Rinaldi, Carlos, E-mail: carlos.rinaldi@bme.ufl.edu [Department of Chemical Engineering, University of Florida, 1030 Center Drive, Gainesville, FL 32611 (United States); J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, 1275 Center Drive, Gainesville, FL 32611 (United States)

    2016-12-01

    Magnetic nanoparticles in alternating magnetic fields (AMFs) transfer some of the field's energy to their surroundings in the form of heat, a property that has attracted significant attention for use in cancer treatment through hyperthermia and in developing magnetic drug carriers that can be actuated to release their cargo externally using magnetic fields. To date, most work in this field has focused on the use of AMFs that actuate heat release by nanoparticles over large regions, without the ability to select specific nanoparticle-loaded regions for heating while leaving other nanoparticle-loaded regions unaffected. In parallel, magnetic particle imaging (MPI) has emerged as a promising approach to image the distribution of magnetic nanoparticle tracers in vivo, with sub-millimeter spatial resolution. The underlying principle in MPI is the application of a selection magnetic field gradient, which defines a small region of low bias field, superimposed with an AMF (of lower frequency and amplitude than those normally used to actuate heating by the nanoparticles) to obtain a signal which is proportional to the concentration of particles in the region of low bias field. Here we extend previous models for estimating the energy dissipation rates of magnetic nanoparticles in uniform AMFs to provide theoretical predictions of how the selection magnetic field gradient used in MPI can be used to selectively actuate heating by magnetic nanoparticles in the low bias field region of the selection magnetic field gradient. Theoretical predictions are given for the spatial decay in energy dissipation rate under magnetic field gradients representative of those that can be achieved with current MPI technology. These results underscore the potential of combining MPI and higher amplitude/frequency actuation AMFs to achieve selective magnetic fluid hyperthermia (MFH) guided by MPI. - Highlights: • SAR predictions based on a field-dependent magnetization relaxation model.

  5. Randomized trial for superiority of high field strength intra-operative magnetic resonance imaging guided resection in pituitary surgery.

    Science.gov (United States)

    Tandon, Vivek; Raheja, Amol; Suri, Ashish; Chandra, P Sarat; Kale, Shashank S; Kumar, Rajinder; Garg, Ajay; Kalaivani, Mani; Pandey, Ravindra M; Sharma, Bhawani S

    2017-03-01

    Till date there are no randomized trials to suggest the superiority of intra-operative magnetic resonance imaging (IOMRI) guided trans-sphenoidal pituitary resection over two dimensional fluoroscopic (2D-F) guided resections. We conducted this trial to establish the superiority of IOMRI in pituitary surgery. Primary objective was to compare extent of tumor resection between the two study arms. It was a prospective, randomized, outcome assessor and statistician blinded, two arm (A: IOMRI, n=25 and B: 2D-F, n=25), parallel group clinical trial. 4 patients from IOMRI group cross-over to 2D-F group and were consequently analyzed in latter group, based on modified intent to treat method. A total of 50 patients were enrolled till completion of trial (n=25 in each study arm). Demographic profile and baseline parameters were comparable among the two arms (p>0.05) except for higher number of endoscopic procedures and experienced neurosurgeons (>10years) in arm B (p=0.02, 0.002 respectively). Extent of resection was similar in both study arms (A, 94.9% vs B, 93.6%; p=0.78), despite adjusting for experience of operating surgeon and use of microscope/endoscope for surgical resection. We observed that use of IOMRI helped optimize the extent of resection in 5/20 patients (25%) for pituitary tumor resection in-group A. Present study failed to observe superiorty of IOMRI over conventional 2D-F guided resection in pituitary macroadenoma surgery. By use of this technology, younger surgeons could validate their results intra-operatively and hence could increase EOR without causing any increase in complications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Magnetic resonance imaging guided transatrial electrophysiological studies in swine using active catheter tracking - experience with 14 cases.

    Science.gov (United States)

    Grothoff, Matthias; Gutberlet, Matthias; Hindricks, Gerhard; Fleiter, Christian; Schnackenburg, Bernhard; Weiss, Steffen; Krueger, Sascha; Piorkowski, Christopher; Gaspar, Thomas; Wedan, Steve; Lloyd, Thomas; Sommer, Philipp; Hilbert, Sebastian

    2017-05-01

    To evaluate the feasibility of performing comprehensive Cardiac Magnetic resonance (CMR) guided electrophysiological (EP) interventions in a porcine model encompassing left atrial access. After introduction of two femoral sheaths 14 swine (41 ± 3.6 kg) were transferred to a 1.5 T MR scanner. A three-dimensional whole-heart sequence was acquired followed by segmentation and the visualization of all heart chambers using an image-guidance platform. Two MR conditional catheters were inserted. The interventional protocol consisted of intubation of the coronary sinus, activation mapping, transseptal left atrial access (n = 4), generation of ablation lesions and eventually ablation of the atrioventricular (AV) node. For visualization of the catheter tip active tracking was used. Catheter positions were confirmed by passive real-time imaging. Total procedure time was 169 ± 51 minutes. The protocol could be completed in 12 swine. Two swine died from AV-ablation induced ventricular fibrillation. Catheters could be visualized and navigated under active tracking almost exclusively. The position of the catheter tips as visualized by active tracking could reliably be confirmed with passive catheter imaging. Comprehensive CMR-guided EP interventions including left atrial access are feasible in swine using active catheter tracking. • Comprehensive CMR-guided electrophysiological interventions including LA access were conducted in swine. • Active catheter-tracking allows efficient catheter navigation also in a transseptal approach. • More MR-conditional tools are needed to facilitate left atrial interventions in humans.

  7. Endogenous Catalytic Generation of O2 Bubbles for In Situ Ultrasound-Guided High Intensity Focused Ultrasound Ablation.

    Science.gov (United States)

    Liu, Tianzhi; Zhang, Nan; Wang, Zhigang; Wu, Meiying; Chen, Yu; Ma, Ming; Chen, Hangrong; Shi, Jianlin

    2017-09-26

    High intensity focused ultrasound (HIFU) surgery generally suffers from poor precision and low efficiency in clinical application, especially for cancer therapy. Herein, a multiscale hybrid catalytic nanoreactor (catalase@MONs, abbreviated as C@M) has been developed as a tumor-sensitive contrast and synergistic agent (C&SA) for ultrasound-guided HIFU cancer surgery, by integrating dendritic-structured mesoporous organosilica nanoparticles (MONs) and catalase immobilized in the large open pore channels of MONs. Such a hybrid nanoreactor exhibited sensitive catalytic activity toward H2O2, facilitating the continuous O2 gas generation in a relatively mild manner even if incubated with 10 μM H2O2, which finally led to enhanced ablation in the tissue-mimicking PAA gel model after HIFU exposure mainly resulting from intensified cavitation effect. The C@M nanoparticles could be accumulated within the H2O2-enriched tumor region through enhanced permeability and retention effect, enabling durable contrast enhancement of ultrasound imaging, and highly efficient tumor ablation under relatively low power of HIFU exposure in vivo. Very different from the traditional perfluorocarbon-based C&SA, such an on-demand catalytic nanoreactor could realize the accurate positioning of tumor without HIFU prestimulation and efficient HIFU ablation with a much safer power output, which is highly desired in clinical HIFU application.

  8. Magnetic Resonance Imaging-Guided Breast Interventions: Role in Biopsy Targeting and Lumpectomies.

    Science.gov (United States)

    Gombos, Eva C; Jagadeesan, Jayender; Richman, Danielle M; Kacher, Daniel F

    2015-11-01

    Contrast-enhanced breast MR imaging is increasingly being used to diagnose breast cancer and to perform biopsy procedures. The American Cancer Society has advised women at high risk for breast cancer to have breast MR imaging screening as an adjunct to screening mammography. This article places special emphasis on biopsy and operative planning involving MR imaging and reviews use of breast MR imaging in monitoring response to neoadjuvant chemotherapy. Described are peer-reviewed data on currently accepted MR imaging-guided procedures for addressing benign and malignant breast diseases, including intraoperative imaging. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Design and fabrication of label-free biochip using a guided mode resonance filter with nano grating structures by injection molding process.

    Science.gov (United States)

    Cho, E; Kim, B; Choi, S; Han, J; Jin, J; Han, J; Lim, J; Heo, Y; Kim, S; Sung, G Y; Kang, S

    2011-01-01

    This paper introduces technology to fabricate a guided mode resonance filter biochip using injection molding. Of the various nanofabrication processes that exist, injection molding is the most suitable for the mass production of polymer nanostructures. Fabrication of a nanograting pattern for guided mode resonance filters by injection molding requires a durable metal stamp, because of the high injection temperature and pressure. Careful consideration of the optimized process parameters is also required to achieve uniform sub-wavelength gratings with high fidelity. In this study, a metallic nanostructure pattern to be used as the stamp for the injection molding process was fabricated using electron beam lithography, a UV nanoimprinting process, and an electroforming process. A one-dimensional nanograting substrate was replicated by injection molding, during which the process parameters were controlled. To evaluate the geometric quality of the injection molded nanograting patterns, the surface profile of the fabricated nanograting for different processing conditions was analyzed using an atomic force microscope and a scanning electron microscope. Finally, to demonstrate the feasibility of the proposed process for fabricating guided mode resonance filter biochips, a high-refractive-index material was deposited on the polymer nanograting and its guided mode resonance characteristics were analyzed.

  10. Magnetic resonance texture parameters are associated with ablation efficiency in MR-guided high-intensity focussed ultrasound treatment of uterine fibroids

    NARCIS (Netherlands)

    Hocquelet, Arnaud; Denis de Senneville, Baudouin|info:eu-repo/dai/nl/413642151; Frulio, Nora; Salut, Cécile; Bouzgarrou, Mounir; Papadopoulos, Panteleimon; Trillaud, Hervé

    2017-01-01

    OBJECTIVES: The objective of this study is to assess the association between texture parameter analysis derived from T2-weighted images and efficiency of magnetic resonance-guided focussed ultrasound (MRgFUS) ablation for the treatment of uterine fibroids. MATERIALS AND METHODS: Fifty-five women

  11. A printed Yagi-Uda antenna for application in magnetic resonance thermometry guided microwave hyperthermia applicators

    Science.gov (United States)

    Paulides, M. M.; Mestrom, R. M. C.; Salim, G.; Adela, B. B.; Numan, W. C. M.; Drizdal, T.; Yeo, D. T. B.; Smolders, A. B.

    2017-03-01

    Biological studies and clinical trials show that addition of hyperthermia stimulates conventional cancer treatment modalities and significantly improves treatment outcome. This supra-additive stimulation can be optimized by adaptive hyperthermia to counteract strong and dynamic thermoregulation. The only clinically proven method for the 3D non-invasive temperature monitoring required is by magnetic resonance (MR) temperature imaging, but the currently available set of MR compatible hyperthermia applicators lack the degree of heat control required. In this work, we present the design and validation of a high-frequency (433 MHz ISM band) printed circuit board antenna with a very low MR-footprint. This design is ideally suited for use in a range of hyperthermia applicator configurations. Experiments emulating the clinical situation show excellent matching properties of the antenna over a 7.2% bandwidth (S 11  phased-arrays.

  12. Surface plasmon resonance sensors a materials guide to design and optimization

    CERN Document Server

    Oliveira, Leiva Casemiro; Thirstrup, Carsten; Neff, Helmut Franz

    2015-01-01

    This book addresses the important physical phenomenon of Surface Plasmon Resonance or Surface Plasmon Polaritons in thin metal films, a phenomenon which is exploited in the design of a large variety of physico-chemical optical sensors. In this treatment, crucial materials aspects for design and optimization of SPR sensors are investigated and outlined in detail. The text covers the selection of nanometer thin metal films, ranging from free-electron to the platinum type conductors, along with their combination with a large variety of dielectric substrate materials, and associated individual layer and opto-geometric arrangements. Furthermore, as-yet hardly explored SPR features of selected metal–metal and metal–dielectric super lattices are included in this report. An in-depth multilayer Fresnel evaluation provides the mathematical tool for this optical analysis, which otherwise relies solely on experimentally determined electro-optical materials parameters.

  13. Established and emerging cardiovascular magnetic resonance techniques for prognostication and guiding therapy in heart failure.

    Science.gov (United States)

    Swoboda, Peter P; Plein, Sven

    2014-01-01

    The syndrome of heart failure is prevalent and a cause of significant morbidity and mortality. Cardiovascular magnetic resonance (CMR) offers a unique method to quantify the extent of left ventricular dysfunction and also characterize the myocardium, particularly according to the presence and distribution of late gadolinium enhancement. The prognostic value of late gadolinium enhancement in various etiologies of heart failure has been demonstrated. Newer techniques that non-invasively assess the extracellular volume may also add to the prognostic value of CMR in heart failure. Management decisions in patients with heart failure can often be complex. CMR can provide useful information when planning cardiac device therapy and the CMR assessment of viability is key when planning revascularization.

  14. SU-E-J-162: Quality Assurance Procedures for MR Guided Focused Ultrasound Treatment of Bone Metastasis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L; Chen, X; Wang, B; Gupta, R; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-06-01

    Purpose: The purpose of this work is to develop and verify our quality assurance (QA) procedures to ensure the safety and efficacy of MR-guided focused ultrasound (MRgFUS) treatment of bone metastases. Methods: A practical QA program was developed. Monthly and daily QA (DQA) procedures were performed. The major QA items included the checks of the machine hardware, software and patient safety features. Briefly, these checks/tests include: 1) the cooling system reservoir and treatment table; 2) power to the treatment table; 3) the MR coil; 4) the transducer position with MRI; 5) image display on the treatment work station; 6) the effective focal spot in 3 directions using MR thermometry; and 7) all the safety devices including a sonication lamp, and the emergency stop-sonication switches. In order to avoid patient skin burn, it is important to remove gas bubbles in the interfaces between the treatment table and the gel pad, and the gel pad and patients skin during the patient setup. Our QA procedures have been verified and evaluated through patient treatments. Seven patients with scapula, humeral head, sacrum, ilium, pubic ramus and acetabular bone metastases were treated using MRgFUS. Results: Our study showed that all seven patients tolerated the MRgFUS treatment well. No skin toxicity or other complications were observed. The pain score (0–10) using the visual analog scale (VAS) was significantly reduced from 8.0 ± 1.1 before treatment to 4.7 ± 3.0, 3.0 ± 1.5, 3.2 ± 2.8 and 3.4 ± 1.5 at one day, one month, two months and three months after the MRgFUS treatment, respectively. Conclusion: We demonstrated that with the appropriate QA procedures, MRgFUS is a safe, effective and noninvasive treatment modality for palliation of bone metastases.

  15. SU-E-T-245: MR Guided Focused Ultrasound Increased PARP Related Apoptosis On Prostate Cancer in Vivo

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L; Chen, X; Cvetkovic, D; Gupta, R; Yang, D; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-06-01

    Purpose: Our previous study demonstrated that significant tumor growth delay was observed in the mice treated with pulsed high intensity focused ultrasound (pHIFU). The purpose of this study is to understand the cell killing mechanisms of pHIFU. Methods: Prostate cancer cells (LNCaP), were grown orthotopically in 17 nude mice. Tumor-bearing mice were treated using pHIFU with an acoustic power of 25W, pulse width 100msec and 300 pulses in one sonication under MR guidance. Mutiple sonications were used to cover the whole tumor volume. Temperature (less than 40 degree centigrade in the focal spot) was monitored using MR thermometry. Animals were euthanized at pre-determined time points (n=2) after treatment: 0 hours; 6 hrs; 24 hrs; 48 hrs; 4 days and 7 days. Two tumorbearing mice were used as control. Three tumor-bearing mice were treated with radiation (RT, 2 Gy) using 6 MV photon beams. RT treated mice were euthanized at 0 hr, 6 hrs and 24 hrs. The tumors were processed for immunohistochemical (IHC) staining for PARP (a surrogate of apoptosis). A multispectral imaging analysis system was used to quantify the expression of PARP staining. Cell apoptosis was calculated based on the PARP expression level, which is the intensity of the DAB reaction. Results: Our data showed that PARP related apoptosis peaked at 48 hrs and 7 days in pHIFU treated mice, which is comparable to that for the RT group at 24 hrs. The preliminary results from this study were consistent with our previous study on tumor growth delay using pHIFU. Conclusion: Our results demonstrated that non-thermal pHIFU increased apoptotic tumor cell death through the PARP related pathway. MR guided pHIFU may have a great potential as a safe, noninvasive treatment modality for cancer therapy. This treatment modality might be able to synergize with PARP inhibitors to achieve better result.

  16. SU-F-J-225: Histology Study of MR Guided Pulsed Focused Ultrasound On Treatment of Prostate Cancer in Vivo

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L; Cvetkovic, D; Chen, X; Wang, B; Gupta, R; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)

    2016-06-15

    Purpose: Our previous study demonstrated significant tumor growth delay in the mice treated with pulsed high intensity focused ultrasound (pHIFU). The purpose of this study is to understand the cell killing mechanisms of pHIFU. Methods: Prostate cancer cells (LNCaP), were grown orthotopically in 17 nude mice. Tumor-bearing mice were treated using pHIFU with an acoustic power of 25W, pulse width 100msec and 300 pulses in one sonication under MR guidance. Mutiple sonications were used to cover the whole tumor volume. The temperature (less than 40 degree centigrade in the focal spot) was monitored using MR thermometry. Animals were euthanized at pre-determined time points (n=2) after treatment: 0 hours; 6 hrs; 24 hrs; 48 hrs; 4 days and 7 days. Two tumorbearing mice were used as control. Three tumor-bearing mice were treated with radiation (RT, 2 Gy) using 6 MV photon beams. RT treated mice were euthanized at 0 hr, 6 hrs and 24 hrs. The tumors were processed for immunohistochemical (IHC) staining for PARP (a surrogate of apoptosis). A multispectral imaging analysis system was used to quantify the expression of PARP staining. Cell apoptosis was calculated based on the PARP expression level using the DAB analysis software. Results: Our data showed that PARP related apoptosis peaked at 48 hrs and 7 days in pHIFU treated mice, which is comparable to that for the RT group at 24 hrs. The preliminary results from this study were consistent with our previous study on tumor growth delay using pHIFU. Conclusion: Our results demonstrated that non-thermal pHIFU increased apoptotic tumor cell death through the PARP related pathway. MR guided pHIFU may have a great potential as a safe, noninvasive treatment modality for cancer therapy. This treatment modality may synergize with PARP inhibitors to achieve better therapeutic result.

  17. Focused parathyroidectomy without intra-operative parathormone monitoring: The value of PTH assay in preoperative ultrasound guided fine needle aspiration washout

    Directory of Open Access Journals (Sweden)

    Fatih Kuzu

    2016-03-01

    Conclusions: The higher level of PTH in preoperative ultrasound guided FNA washout is a considerable data to predict the correct localization of HP, particularly in circumstances of greater values than the serum PTH level. However, although its specificity is high, in cases of coexisting nodular thyroid disease, associated additional HP might be missed at focused parathyroidectomy without PTH monitoring, leading to recurrent disease.

  18. Comparing implementations of magnetic-resonance-guided fluorescence molecular tomography for diagnostic classification of brain tumors

    Science.gov (United States)

    Davis, Scott C.; Samkoe, Kimberley S.; O'Hara, Julia A.; Gibbs-Strauss, Summer L.; Paulsen, Keith D.; Pogue, Brian W.

    2010-09-01

    Fluorescence molecular tomography (FMT) systems coupled to conventional imaging modalities such as magnetic resonance imaging (MRI) and computed tomography provide unique opportunities to combine data sets and improve image quality and content. Yet, the ideal approach to combine these complementary data is still not obvious. This preclinical study compares several methods for incorporating MRI spatial prior information into FMT imaging algorithms in the context of in vivo tissue diagnosis. Populations of mice inoculated with brain tumors that expressed either high or low levels of epidermal growth factor receptor (EGFR) were imaged using an EGF-bound near-infrared dye and a spectrometer-based MRI-FMT scanner. All data were spectrally unmixed to extract the dye fluorescence from the tissue autofluorescence. Methods to combine the two data sets were compared using student's t-tests and receiver operating characteristic analysis. Bulk fluorescence measurements that made up the optical imaging data set were also considered in the comparison. While most techniques were able to distinguish EGFR(+) tumors from EGFR(-) tumors and control animals, with area-under-the-curve values=1, only a handful were able to distinguish EGFR(-) tumors from controls. Bulk fluorescence spectroscopy techniques performed as well as most imaging techniques, suggesting that complex imaging algorithms may be unnecessary to diagnose EGFR status in these tissue volumes.

  19. Limbic Activity Modulation Guided by Functional Magnetic Resonance Imaging-Inspired Electroencephalography Improves Implicit Emotion Regulation.

    Science.gov (United States)

    Keynan, Jackob N; Meir-Hasson, Yehudit; Gilam, Gadi; Cohen, Avihay; Jackont, Gilan; Kinreich, Sivan; Ikar, Limor; Or-Borichev, Ayelet; Etkin, Amit; Gyurak, Anett; Klovatch, Ilana; Intrator, Nathan; Hendler, Talma

    2016-09-15

    The amygdala has a pivotal role in processing traumatic stress; hence, gaining control over its activity could facilitate adaptive mechanism and recovery. To date, amygdala volitional regulation could be obtained only via real-time functional magnetic resonance imaging (fMRI), a highly inaccessible procedure. The current article presents high-impact neurobehavioral implications of a novel imaging approach that enables bedside monitoring of amygdala activity using fMRI-inspired electroencephalography (EEG), hereafter termed amygdala-electrical fingerprint (amyg-EFP). Simultaneous EEG/fMRI indicated that the amyg-EFP reliably predicts amygdala-blood oxygen level-dependent activity. Implementing the amyg-EFP in neurofeedback demonstrated that learned downregulation of the amyg-EFP facilitated volitional downregulation of amygdala-blood oxygen level-dependent activity via real-time fMRI and manifested as reduced amygdala reactivity to visual stimuli. Behavioral evidence further emphasized the therapeutic potential of this approach by showing improved implicit emotion regulation following amyg-EFP neurofeedback. Additional EFP models denoting different brain regions could provide a library of localized activity for low-cost and highly accessible brain-based diagnosis and treatment. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  20. Integration of 3D electroanatomic maps and magnetic resonance scar characterization into the navigation system to guide ventricular tachycardia ablation.

    Science.gov (United States)

    Andreu, David; Berruezo, Antonio; Ortiz-Pérez, José T; Silva, Etelvino; Mont, Lluis; Borràs, Roger; de Caralt, Teresa María; Perea, Rosario Jesús; Fernández-Armenta, Juan; Zeljko, Hrvojka; Brugada, Josep

    2011-10-01

    Scar heterogeneity identified with contrast-enhanced cardiac magnetic resonance (CE-CMR) has been related to its arrhythmogenic potential by using different algorithms. The purpose of the study was to identify the algorithm that best fits with the electroanatomic voltage maps (EAM) to guide ventricular tachycardia (VT) ablation. Three-dimensional scar reconstructions from preprocedural CE-CMR study at 3T were obtained and compared with EAMs of 10 ischemic patients submitted for a VT ablation. Three-dimensional scar reconstructions were created for the core (3D-CORE) and border zone (3D-BZ), applying cutoff values of 50%, 60%, and 70% of the maximum pixel signal intensity to discriminate between core and BZ. The left ventricular cavity from CE-CMR (3D-LV) was merged with the EAM, and the 3D-CORE and 3D-BZ were compared with the corresponding EAM areas defined with standard cutoff voltage values. The best match was obtained when a cutoff value of 60% of the maximum pixel signal intensity was used, both for core (r(2)=0.827; P<0.001) and BZ (r(2)=0.511; P=0.020), identifying 69% of conducting channels (CC) observed in the EAM. Matching improved when only the subendocardial half of the wall was segmented (CORE: r(2)=0.808; P<0.001 and BZ: r(2)=0.485; P=0.025), identifying 81% of CC. When comparing the location of each bipolar voltage intracardiac electrogram with respect to the 3D CE-CMR-derived structures, a Cohen κ coefficient of 0.70 was obtained. Scar characterization by means of high resolution CE-CMR resembles that of EAM and can be integrated into the CARTO system to guide VT ablation.

  1. Magnetic resonance guided focused ultrasound surgery (MRgFUS) of bone metastases: From primary pain palliation to local tumor control

    Science.gov (United States)

    Napoli, A.; Leonardi, A.; Andrani, F.; Boni, F.; Anzidei, M.; Catalano, C.

    2017-03-01

    Purpose: To evaluate the clinical performance of MRgFUS in primary pain palliation of painful bone metastases and in local tumor control. Materials and Methods: We enrolled 26 consecutive patients (female/male 12/14; age: 64.7±7.5yrs) with painful bone metastases. Before and 3 months after MRgFUS treatment pain severity and pain interference scores were assessed according to Brief Pain Inventory-Quality of Life (BPI-QoL) criteria and patients underwent both CT and MRI. Local tumor control was evaluated according to lesion size, density and perfusion at CT, dynamic contrast enhancement at MRI (Discovery 750HD, GE; Gd-Bopta, Bracco) and metabolic activity at PET or scintigraphy. Patients were classified as responders or non-responders. Results: No treatment-related adverse events were recorded during the study. As statistically significant difference between baseline and follow-up values for both pain severity and pain interference scores was observed (pmean SUV=1.2). Conclusion: MRgFUS can be safely and effectively used as the primary treatment for pain palliation in patients with painful bone metastases; moreover our experience demonstrated also a potential role for the MRgFUS in local tumor control.

  2. Magnetic resonance imaging as a predictor of submucous cleft palate severity and guide for surgical intervention.

    Science.gov (United States)

    Argenta, Anne; Petropoulou, Kalliopi; Cray, Jim; Ford, Matthew; Jiang, Shao; Losee, Joseph; Grunwaldt, Lorelei

    2013-05-01

    Diagnosis of submucous cleft palate (SMCP) is frequently delayed, adversely affecting speech outcomes. Previous studies show that MRI reliably identifies structural abnormalities in velopharyngeal musculature. This information has potential to assist with diagnosis and treatment decisions. The objectives of this study were to (1) develop a clinician-friendly MRI grading scale of SMCP anatomy, (2) identify correlations between radiographic cleft severity and clinical severity using Pittsburgh Weighted Speech Scores (PWSS), and (3) determine if MRI is a predictor of surgical efficacy in improving PWSS. Thirty patients presenting to our Cleft Palate-Craniofacial Clinic for evaluation of velopharyngeal insufficiency (VPI) and suspected SMCP were reviewed. VPI severity was clinically graded using PWSS. All patients underwent MRI to grade palatal abnormalities, using a novel MRI grading scale. PWSS and cleft severity on MRI were compared. A subgroup of patients (n = 19) underwent palatoplasty. Preoperative and postoperative PWSS were compared. Degree of PWSS improvement was then correlated with the preoperative MRI grade. Twenty-nine out of 30 MRIs demonstrated abnormal palate anatomy. Of the 30 patients evaluated, 5 clinically improved with speech therapy alone. In this subgroup, MRI severity did not correlate with PWSS (P = 0.06-0.6). Nineteen patients underwent palatoplasty. Of these, 14 demonstrated improved postoperative PWSS. There were no significant correlations between severity of cleft on imaging and preoperative PWSS or score improvement (P = 0.056-0.65). While MRI accurately identifies structural abnormalities of the soft palate, these abnormalities do not reliably correspond to clinical severity. Clinical examination including speech scores and dynamic speech testing, rather than static MRI, should guide treatment decisions and surgical indications.

  3. Real-time magnetic resonance imaging-guided frameless stereotactic brain biopsy: technical note.

    Science.gov (United States)

    Mohyeldin, Ahmed; Lonser, Russell R; Elder, J Bradley

    2016-04-01

    The object of this study was to assess the feasibility, accuracy, and safety of real-time MRI-compatible frameless stereotactic brain biopsy. Clinical, imaging, and histological data in consecutive patients who underwent stereotactic brain biopsy using a frameless real-time MRI system were analyzed. Five consecutive patients (4 males, 1 female) were included in this study. The mean age at biopsy was 45.8 years (range 29-60 years). Real-time MRI permitted concurrent display of the biopsy cannula trajectory and tip during placement at the target. The mean target depth of biopsied lesions was 71.3 mm (range 60.4-80.4 mm). Targeting accuracy analysis revealed a mean radial error of 1.3 ± 1.1 mm (mean ± standard deviation), mean depth error of 0.7 ± 0.3 mm, and a mean absolute tip error of 1.5 ± 1.1 mm. There was no correlation between target depth and absolute tip error (Pearson product-moment correlation coefficient, r = 0.22). All biopsy cannulae were placed at the target with a single penetration and resulted in a diagnostic specimen in all cases. Histopathological evaluation of biopsy samples revealed dysembryoplastic neuroepithelial tumor (1 case), breast carcinoma (1 case), and glioblastoma multiforme (3 cases). The ability to place a biopsy cannula under real-time imaging guidance permits on-the-fly alterations in the cannula trajectory and/or tip placement. Real-time imaging during MRI-guided brain biopsy provides precise safe targeting of brain lesions.

  4. Focused parathyroidectomy guided by intra-operative parathormone monitoring does not miss multiglandular disease in patients with sporadic primary hyperparathyroidism: a 10-year outcome.

    Science.gov (United States)

    Lew, John I; Irvin, George L

    2009-12-01

    There remains concern that focused parathyroidectomy guided by intra-operative parathormone monitoring (IPM) will miss multiglandular disease (MGD) leading to a higher recurrence rate. This study reports the 10-year outcome of patients with sporadic primary hyperparathyroidism treated by focused parathyroidectomy guided by IPM. From 1993 to 1998, 173 consecutive patients with sporadic primary hyperparathyroidism underwent focused parathyroidectomy guided by IPM. When IPM showed >50% decrease 10 minutes after abnormal gland excision, the operation was completed. Recurrent hyperparathyroidism was defined as elevated serum calcium and parathormone (PTH) levels >6 months after successful parathyroidectomy. There were 164 patients with a mean follow-up of 83 months. In this group, 96% patients had single gland disease (SGD) and 4% had MGD. Five (3%) patients developed recurrent hyperparathyroidism at 2, 4, 9, 10, and 12 years. In 43 eucalcemic patients followed for >10 years, PTH levels remained normal in 54%, were constantly above normal range in 2%, or varied between normal and above normal range in 44%. In patients 10 years after treatment, IPM-guided parathyroidectomy does not fail to identify MGD, allows for limited dissection in SGD, and shows that various sized parathyroid glands left in situ do not cause higher recurrence rates.

  5. Cavitation-enhanced MR-guided focused ultrasound ablation of rabbit tumors in vivo using phase shift nanoemulsions

    Science.gov (United States)

    Kopechek, Jonathan A; Park, Eun-Joo; Zhang, Yong-Zhi; Vykhodtseva, Natalia I; McDannold, Nathan J; Porter, Tyrone M

    2014-01-01

    Advanced tumors are often inoperable due to their size and proximity to critical vascular structures. High intensity focused ultrasound (HIFU) has been developed to non-invasively thermally ablate inoperable solid tumors. However, the clinical feasibility of HIFU ablation therapy has been limited by the long treatment times (on the order of hours) and high acoustic intensities required. Studies have shown that inertial cavitation can enhance HIFU-mediated heating by generating broadband acoustic emissions that increase tissue absorption and accelerate HIFU-induced heating. Unfortunately, initiating inertial cavitation in tumors requires high intensities and can be unpredictable. To address this need, phase-shift nanoemulsions (PSNE) have been developed. PSNE consist of lipid-coated liquid perfluorocarbon droplets that are less than 200 nm in diameter, thereby allowing passive accumulation in tumors through leaky tumor vasculature. PSNE can be vaporized into microbubbles in tumors in order to nucleate cavitation activity and enhance HIFU-mediated heating. In this study, MR-guided HIFU treatments were performed on intramuscular rabbit VX2 tumors in vivo to assess the effect of vaporized PSNE on acoustic cavitation and HIFU-mediated heating. HIFU pulses were delivered for 30 seconds using a 1.5 MHz, MR-compatible transducer, and cavitation emissions were recorded with a 650-kHz ring hydrophone while temperature was monitored using MR thermometry. Cavitation emissions were significantly higher (P<0.05) after PSNE injection and this was well correlated with enhanced HIFU-mediated heating in tumors. The peak temperature rise induced by sonication was significantly higher (P<0.05) after PSNE injection. For example, the mean percent change in temperature achieved at 5.2 W of acoustic power was 46 ± 22% with PSNE injection. The results indicate that PSNE nucleates cavitation which correlates with enhanced HIFU-mediated heating in tumors. This suggests that PSNE could

  6. Magnetic Resonance–Guided High-Intensity Focused Ultrasound Hyperthermia for Recurrent Rectal Cancer: MR Thermometry Evaluation and Preclinical Validation

    Energy Technology Data Exchange (ETDEWEB)

    Chu, William, E-mail: William.Chu@sunnybrook.ca [Department of Radiation Oncology, Sunnybrook Health Sciences Centre and the University of Toronto, Toronto, Ontario (Canada); Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario (Canada); Staruch, Robert M. [Clinical Sites Research Program, Philips Research, Cambridge, Massachusetts (United States); Pichardo, Samuel [Thunder Bay Regional Research Institute, Thunder Bay, Ontario (Canada); Physics and Electrical Engineering, Lakehead University, Thunder Bay, Ontario (Canada); Tillander, Matti; Köhler, Max O. [MR Therapy, Philips Healthcare, Vantaa (Finland); Huang, Yuexi [Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario (Canada); Ylihautala, Mika [MR Therapy, Philips Healthcare, Vantaa (Finland); McGuffin, Merrylee [Department of Radiation Oncology, Sunnybrook Health Sciences Centre and the University of Toronto, Toronto, Ontario (Canada); Czarnota, Gregory [Department of Radiation Oncology, Sunnybrook Health Sciences Centre and the University of Toronto, Toronto, Ontario (Canada); Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario (Canada); Hynynen, Kullervo [Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario (Canada)

    2016-07-15

    Purpose: To evaluate the feasibility of magnetic resonance–guided high-intensity focused ultrasound (MR-HIFU) mild hyperthermia in deep tissue targets for enhancing radiation therapy and chemotherapy in the context of recurrent rectal cancer. A preclinical study was performed to evaluate the safety and performance of MR-HIFU mild hyperthermia. A prospective imaging study was performed in volunteers with rectal cancer to evaluate MR thermometry quality near the rectum and accessibility of rectal tumors using MR-HIFU. Methods and Materials: Mild hyperthermia was performed in pig thigh (9 sonications, 6 pigs) using a clinical MR-HIFU system. Targets near the rectal wall and deep thigh were evaluated. Thermal maps obtained in 6 planes every 3.2 seconds were used to control sonications in 18-mm diameter treatment regions at temperatures of 42°C to 42.5°C for 10 to 60 minutes. Volunteer imaging-only studies to assess the quality of MR thermometry (without heating) were approved by the institutional research ethics board. Anatomic and MR thermometry images were acquired in consenting volunteers with rectal cancer. In 3 of 6 study participants, rectal filling with saline was used to reduce motion-related MR thermometry artifacts near the tumor. Results: In pigs, mean target temperature matched the desired hyperthermia temperature within 0.2°C; temporal standard deviation ≤0.5°C. With optimized control thresholds, no undesired tissue damage was observed. In human volunteers, MR temperature measurements had adequate precision and stability, especially when rectal filling was used to reduce bowel motion. Conclusions: In pigs, MR-HIFU can safely deliver mild hyperthermia (41°C-43°C) to a targeted volume for 30 minutes. In humans, careful patient selection and preparation will enable adequate targeting for recurrent rectal cancers and sufficient MR temperature mapping stability to control mild hyperthermia. These results enable human trials of MR-HIFU hyperthermia.

  7. Preclinical evaluation of a low-frequency transcranial MRI-guided focused ultrasound system in a primate model

    Science.gov (United States)

    McDannold, Nathan; Livingstone, Margaret; Barış Top, Can; Sutton, Jonathan; Todd, Nick; Vykhodtseva, Natalia

    2016-11-01

    This study investigated thermal ablation and skull-induced heating with a 230 kHz transcranial MRI-guided focused ultrasound (TcMRgFUS) system in nonhuman primates. We evaluated real-time acoustic feedback and aimed to understand whether cavitation contributed to the heating and the lesion formation. In four macaques, we sonicated thalamic targets at acoustic powers of 34-560 W (896-7590 J). Tissue effects evaluated with MRI and histology were compared to MRI-based temperature and thermal dose measurements, acoustic emissions recorded during the experiments, and acoustic and thermal simulations. Peak temperatures ranged from 46 to 57 °C, and lesions were produced in 5/8 sonicated targets. A linear relationship was observed between the applied acoustic energy and both the focal and brain surface heating. Thermal dose thresholds were 15-50 cumulative equivalent minutes at 43 °C, similar to prior studies at higher frequencies. Histology was also consistent with earlier studies of thermal effects in the brain. The system successfully controlled the power level and maintained a low level of cavitation activity. Increased acoustic emissions observed in 3/4 animals occurred when the focal temperature rise exceeded approximately 16 °C. Thresholds for thermally-significant subharmonic and wideband emissions were 129 and 140 W, respectively, corresponding to estimated pressure amplitudes of 2.1 and 2.2 MPa. Simulated focal heating was consistent with the measurements for sonications without thermally-significant acoustic emissions; otherwise it was consistently lower than the measurements. Overall, these results suggest that the lesions were produced by thermal mechanisms. The detected acoustic emissions, however, and their association with heating suggest that cavitation might have contributed to the focal heating. Compared to earlier work with a 670 kHz TcMRgFUS system, the brain surface heating was substantially reduced and the focal heating was higher with this

  8. MR-Guided Delivery of Hydrophilic Molecular Imaging Agents Across the Blood-Brain Barrier Through Focused Ultrasound.

    Science.gov (United States)

    Airan, Raag D; Foss, Catherine A; Ellens, Nicholas P K; Wang, Yuchuan; Mease, Ronnie C; Farahani, Keyvan; Pomper, Martin G

    2017-02-01

    A wide variety of hydrophilic imaging and therapeutic agents are unable to gain access to the central nervous system (CNS) due to the blood-brain barrier (BBB). In particular, unless a particular transporter exists that may transport the agent across the BBB, most agents that are larger than 500 Da or that are hydrophilic will be excluded by the BBB. Glutamate carboxypeptidase II (GCPII), also known as the prostate-specific membrane antigen (PSMA) in the periphery, has been implicated in various neuropsychiatric conditions. As all agents that target GCPII are hydrophilic and thereby excluded from the CNS, we used GCPII as a platform for demonstrating our MR-guided focused ultrasound (MRgFUS) technique for delivery of GCPII/PSMA-specific imaging agents to the brain. Female rats underwent MRgFUS-mediated opening of the BBB. After opening of the BBB, either a radio- or fluorescently labeled ureido-based ligand for GCPII/PSMA was administered intravenously. Brain uptake was assessed for 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid ([18F]DCFPyL) and YC-27, two compounds known to bind GCPII/PSMA with high affinity, using positron emission tomography (PET) and near-infrared fluorescence (NIRF) imaging, respectively. Specificity of ligand binding to GCPII/PSMA in the brain was determined with co-administration of a molar excess of ZJ-43, a compound of the same chemical class but different structure from either [18F]DCFPyL or YC-27, which competes for GCPII/PSMA binding. Dynamic PET imaging using [18F]DCFPyL demonstrated that target uptake reached a plateau by ∼1 h after radiotracer administration, with target/background ratios continuing to increase throughout the course of imaging, from a ratio of ∼4:1 at 45 min to ∼7:1 by 80 min. NIRF imaging likewise demonstrated delivery of YC-27 to the brain, with clear visualization of tracer in the brain at 24 h. Tissue uptake of both ligands was greatly diminished by ZJ

  9. Quality of MR thermometry during palliative MR-guided high-intensity focused ultrasound (MR-HIFU) treatment of bone metastases.

    Science.gov (United States)

    Lam, Mie K; Huisman, Merel; Nijenhuis, Robbert J; van den Bosch, Maurice Aaj; Viergever, Max A; Moonen, Chrit Tw; Bartels, Lambertus W

    2015-01-01

    Magnetic resonance (MR)-guided high-intensity focused ultrasound has emerged as a clinical option for palliative treatment of painful bone metastases, with MR thermometry (MRT) used for treatment monitoring. In this study, the general image quality of the MRT was assessed in terms of signal-to-noise ratio (SNR) and apparent temperature variation. Also, MRT artifacts were scored for their occurrence and hampering of the treatment monitoring. Analyses were performed on 224 MRT datasets retrieved from 13 treatments. The SNR was measured per voxel over time in magnitude images, in the target lesion and surrounding muscle, and was averaged per treatment. The standard deviation over time of the measured temperature per voxel in MRT images, in the muscle outside the heated region, was defined as the apparent temperature variation and was averaged per treatment. The scored MRT artifacts originated from the following sources: respiratory and non-respiratory time-varying field inhomogeneities, arterial ghosting, and patient motion by muscle contraction and by gross body movement. Distinction was made between lesion type, location, and procedural sedation and analgesic (PSA). The average SNR was highest in and around osteolytic lesions (21 in lesions, 27 in surrounding muscle, n = 4) and lowest in the upper body (9 in lesions, 16 in surrounding muscle, n = 4). The average apparent temperature variation was lowest in osteolytic lesions (1.2°C, n = 4) and the highest in the upper body (1.7°C, n = 4). Respiratory time-varying field inhomogeneity MRT artifacts occurred in 85% of the datasets and hampered treatment monitoring in 81%. Non-respiratory time-varying field inhomogeneities and arterial ghosting MRT artifacts were most frequent (94% and 95%) but occurred only locally. Patient motion artifacts were highly variable and occurred less in treatments of osteolytic lesions and using propofol and esketamine as PSA. In this study, the general image quality of

  10. Differentiation of Crataegus spp. guided by nuclear magnetic resonance spectrometry with chemometric analyses.

    Science.gov (United States)

    Lund, Jensen A; Brown, Paula N; Shipley, Paul R

    2017-09-01

    For compliance with US Current Good Manufacturing Practice regulations for dietary supplements, manufacturers must provide identity of source plant material. Despite the popularity of hawthorn as a dietary supplement, relatively little is known about the comparative phytochemistry of different hawthorn species, and in particular North American hawthorns. The combination of NMR spectrometry with chemometric analyses offers an innovative approach to differentiating hawthorn species and exploring the phytochemistry. Two European and two North American species, harvested from a farm trial in late summer 2008, were analyzed by standard 1D 1H and J-resolved (JRES) experiments. The data were preprocessed and modelled by principal component analysis (PCA). A supervised model was then generated by partial least squares-discriminant analysis (PLS-DA) for classification and evaluated by cross validation. Supervised random forests models were constructed from the dataset to explore the potential of machine learning for identification of unique patterns across species. 1D 1H NMR data yielded increased differentiation over the JRES data. The random forests results correlated with PLS-DA results and outperformed PLS-DA in classification accuracy. In all of these analyses differentiation of the Crataegus spp. was best achieved by focusing on the NMR spectral region that contains signals unique to plant phenolic compounds. Identification of potentially significant metabolites for differentiation between species was approached using univariate techniques including significance analysis of microarrays and Kruskall-Wallis tests. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Neuronavigation-guided focused ultrasound-induced blood-brain barrier opening: A preliminary study in swine

    Science.gov (United States)

    Liu, Hao-Li; Tsai, Hong-Chieh; Lu, Yu-Jen; Wei, Kuo-Chen

    2012-11-01

    FUS-induced BBB opening is a promising technique for noninvasive and local delivery of drugs into the brain. Here we propose the novel use of a neuronavigation system to guide the FUS-induced BBB opening procedure, and investigate its feasibility in vivo in large animals. We developed an interface between the neuronavigator and FUS to allow guidance of the focal energy produced by the FUS transducer. The system was tested in 29 pigs by more than 40 sonication procedures and evaluated by MRI. Gd-DTPA concentration was quantitated in vivo by MRI R1 relaxometry and compared by ICP-OES assay. Brain histology after FUS exposure was investigated by HE and TUNEL staining. Neuronavigation could successfully guide the focal beam with comparable precision to neurosurgical stereotactic procedures (2.3 ± 0.9 mm). FUS pressure of 0.43 MPa resulted in consistent BBB-opening. Neuronavigation-guided BBB-opening increased Gd-DTPA deposition by up to 1.83 mM (140% increase). MR relaxometry demonstrated high correlation to ICP-OES measurements (r2 = 0.822), suggesting that Gd-DTPA deposition can be directly measured by imaging. Neuronavigation could provide sufficient precision for guiding FUS to temporally and locally open the BBB. Gd-DTPA deposition in the brain could be quantified by MR relaxometry, providing a potential tool for the in vivo quantification of therapeutic agents in CNS disease treatment.

  12. Vision 20/20: Magnetic resonance imaging-guided attenuation correction in PET/MRI: Challenges, solutions, and opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Mehranian, Abolfazl; Arabi, Hossein [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Zaidi, Habib, E-mail: habib.zaidi@hcuge.ch [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva CH-1211 (Switzerland); Geneva Neuroscience Centre, University of Geneva, Geneva CH-1205 (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, Groningen 9700 RB (Netherlands)

    2016-03-15

    Attenuation correction is an essential component of the long chain of data correction techniques required to achieve the full potential of quantitative positron emission tomography (PET) imaging. The development of combined PET/magnetic resonance imaging (MRI) systems mandated the widespread interest in developing novel strategies for deriving accurate attenuation maps with the aim to improve the quantitative accuracy of these emerging hybrid imaging systems. The attenuation map in PET/MRI should ideally be derived from anatomical MR images; however, MRI intensities reflect proton density and relaxation time properties of biological tissues rather than their electron density and photon attenuation properties. Therefore, in contrast to PET/computed tomography, there is a lack of standardized global mapping between the intensities of MRI signal and linear attenuation coefficients at 511 keV. Moreover, in standard MRI sequences, bones and lung tissues do not produce measurable signals owing to their low proton density and short transverse relaxation times. MR images are also inevitably subject to artifacts that degrade their quality, thus compromising their applicability for the task of attenuation correction in PET/MRI. MRI-guided attenuation correction strategies can be classified in three broad categories: (i) segmentation-based approaches, (ii) atlas-registration and machine learning methods, and (iii) emission/transmission-based approaches. This paper summarizes past and current state-of-the-art developments and latest advances in PET/MRI attenuation correction. The advantages and drawbacks of each approach for addressing the challenges of MR-based attenuation correction are comprehensively described. The opportunities brought by both MRI and PET imaging modalities for deriving accurate attenuation maps and improving PET quantification will be elaborated. Future prospects and potential clinical applications of these techniques and their integration in commercial

  13. Distribution of abnormal potentials in chronic myocardial infarction using a real time magnetic resonance guided electrophysiology system.

    Science.gov (United States)

    Oduneye, Samuel O; Pop, Mihaela; Shurrab, Mohammed; Biswas, Labonny; Ramanan, Venkat; Barry, Jennifer; Crystal, Eugene; Wright, Graham A

    2015-04-11

    Identification of viable slow conduction zones manifested by abnormal local potentials is integral to catheter ablation of ventricular tachycardia (VT) sites. The relationship between contrast patterns in cardiovascular magnetic resonance (CMR) and local electrical mapping is not well characterized. The purpose of this study was to identify regions of isolated, late and fractionated diastolic potentials in sinus rhythm and controlled-paced rhythm in post-infarct animals relative to regions detected by late gadolinium enhancement CMR (LGE-CMR). Using a real-time MR-guided electrophysiology system, electrogram (EGM) recordings were used to generate endocardial electroanatomical maps in 6 animals. LGE-CMR was also performed and tissue classification (dense infarct, gray zone and healthy myocardium) was then correlated to locations of abnormal potentials. For abnormal potentials in sinus rhythm, relative occurrence was equivalent 24%, 27% and 22% in dense scar, gray zone and healthy tissue respectively (p = NS); in paced rhythm, the relative occurrence of abnormal potentials was found to be different with 30%, 42% and 21% in dense scar, gray zone and healthy myocardium respectively (p = 0.001). For location of potentials, in the paced case, the relative frequency of abnormal EGMs was 19.9%, 65.4% and 14.7% in the entry, central pathway and exit respectively (p = 0.05), putative regions being defined by activation times. Our data suggests that gray zone quantified by LGE-CMR exhibits abnormal potentials more frequently than in healthy tissue or dense infarct when right ventricular apex pacing is used.

  14. Combined x-ray and magnetic resonance imaging facility: application to image-guided stereotactic and functional neurosurgery.

    Science.gov (United States)

    Hunsche, Stefan; Sauner, Dieter; Maarouf, Mohammad; Lackner, Klaus; Sturm, Volker; Treuer, Harald

    2007-04-01

    To assess the feasibility of a hybrid imaging setup combining x-ray and magnetic resonance imaging (MRI) in the setting of both stereotactic and functional neurosurgery. A combined x-ray and MRI scanning facility with a trolley system for a fast patient transfer between both modalities was installed in a neurosurgical setting. A registration algorithm for fusion of MRI scans and x-ray images was derived for augmentation of fluoroscopic x-ray projection images with MRI scan data, such as anatomic structures and planned probe trajectories. Phantom measurements were obtained between both modalities for estimation of registration accuracy. Practical application of our system in stereotactic and functional neurosurgery was tested in brachytherapy, deep brain stimulation, and motor cortex stimulation. Phantom measurements yielded a mean spatial deviation of 0.7 +/- 0.3 mm with a maximum deviation of 1.1 mm for MRI scans versus x-rays. Augmentation of x-ray images with MRI scan data allowed intraoperative verification of the planned trajectory and target in three types of neurosurgical procedures: positioning iodine seeds in brachytherapy in one case with cerebellar metastasis, placement of electrodes for deep brain stimulation in two cases of advanced Parkinson's disease, and placement of an epidural grid for motor cortex stimulation in two cases of intractable pain. Combined x-ray and MRI-guided stereotactic and functional neurosurgery is feasible. Augmentation of x-ray projection images with MRI scan data, such as planned probe trajectories and MRI scan segmented anatomic structures may be beneficial for probe guidance in stereotactic and functional neurosurgery.

  15. Characterizing mobility from the prosthetic limb user's perspective: Use of focus groups to guide development of the Prosthetic Limb Users Survey of Mobility.

    Science.gov (United States)

    Hafner, Brian J; Morgan, Sara J; Abrahamson, Daniel C; Amtmann, Dagmar

    2016-10-01

    Input from target respondents in the development of patient-reported outcome measures is necessary to ensure that the instrument is meaningful. To solicit perspectives of prosthetic limb users about their mobility experiences and to inform development of the Prosthetic Limb Users Survey of Mobility. Qualitative study. Four focus groups of lower limb prosthesis users were held in different regions of the United States. Focus group transcripts were coded, and themes were identified. Feedback from participants was used to develop a framework for measuring mobility with a lower limb prosthesis. Focus group participants (N = 37) described mobility as a confluence of factors that included characteristics of the individual, activity, and environment. Identified themes were defined as individual characteristics, forms of movement, and environmental situations. Prosthetic mobility was conceptualized as movement activities performed in an environmental or situational context. Respondent feedback used to guide development of Prosthetic Limb Users Survey of Mobility established a foundation for a new person-centered measure of mobility with a prosthetic limb. Perspectives of target respondents are needed to guide development of instruments intended to measure health outcomes. Focus groups of prosthetic limb users were conducted to solicit experiences related to mobility with a lower limb prosthesis. Results were used to inform development of a clinically meaningful, person-centered instrument. © The International Society for Prosthetics and Orthotics 2015.

  16. Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU: Pilot Study in a Swine Model.

    Directory of Open Access Journals (Sweden)

    Merel Huisman

    Full Text Available Ultrasound (US-guided high intensity focused ultrasound (HIFU has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic resonance (MR-imaging guidance may overcome these limitations and MR-guided HIFU (MR-HIFU has been used successfully for other clinical indications. The primary purpose of this study was to evaluate the feasibility of utilizing 3D MR neurography to identify and guide ablation of peripheral nerves using a clinical MR-HIFU system.Volumetric MR-HIFU was used to induce lesions in the peripheral nerves of the lower limbs in three pigs. Diffusion-prep MR neurography and T1-weighted images were utilized to identify the target, plan treatment and immediate post-treatment evaluation. For each treatment, one 8 or 12 mm diameter treatment cell was used (sonication duration 20 s and 36 s, power 160-300 W. Peripheral nerves were extracted < 3 hours after treatment. Ablation dimensions were calculated from thermal maps, post-contrast MRI and macroscopy. Histological analysis included standard H&E staining, Masson's trichrome and toluidine blue staining.All targeted peripheral nerves were identifiable on MR neurography and T1-weighted images and could be accurately ablated with a single exposure of focused ultrasound, with peak temperatures of 60.3 to 85.7°C. The lesion dimensions as measured on MR neurography were similar to the lesion dimensions as measured on CE-T1, thermal dose maps, and macroscopy. Histology indicated major hyperacute peripheral nerve damage, mostly confined to the location targeted for ablation.Our preliminary results indicate that targeted peripheral nerve ablation is feasible with MR-HIFU. Diffusion-prep 3D MR neurography has potential for guiding therapy procedures where either nerve targeting or avoidance is desired, and may also have potential for post

  17. Magnetic resonance guided optical spectroscopy imaging of human breast cancer using a combined frequency domain and continuous wave approach

    Science.gov (United States)

    Mastanduno, Michael A.; Davis, Scott C.; Jiang, Shudong; diFlorio-Alexander, Roberta; Pogue, Brian W.; Paulsen, Keith D.

    2012-03-01

    Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is used to image high-risk patients for breast cancer because of its higher sensitivity to tumors (approaching 100%) than traditional x-ray mammography. We focus on Near Infrared Spectroscopy (NIRS) as an emerging functional and molecular imaging technique that non-invasively quantifies optical properties of total hemoglobin, oxygen saturation, water content, scattering, and lipid concentration to increase the relatively low specificity of DCE-MRI. Our optical imaging system combines six frequency domain wavelengths, measured using PMT detectors with three continuous wave wavelengths measured using CCD/spectrometers. We present methods on combining the synergistic attributes of DCE-MR and NIRS for in-vivo imaging of breast cancer in three dimensions using a custom optical MR breast coil and diffusion based light modeling software, NIRFAST. We present results from phantom studies, healthy subjects, and breast cancer patients. Preliminary results show contrast recovery within 10% in phantoms and spatial resolution less than 5mm. Images from healthy subjects were recovered with properties similar to literature values and previous studies. Patient images have shown elevated total hemoglobin values and water fraction, agreeing with histology and previous results. The additional information gained from NIRS may improve the ability to distinguish between malignant and benign lesions during MR imaging. These dual modality instruments will provide complex anatomical and molecular prognostic information, and may decrease the number of biopsies, thereby improving patient care.

  18. Feasibility of trauma-focused Guided Imagery and Music with adult refugees diagnosed with PTSD – a pilot study

    DEFF Research Database (Denmark)

    Beck, Bolette Daniels; Messel, Catharina; Meyer, Steen

    2017-01-01

    Traumatized refugees seeking treatment in special units of psychiatry are in need of treatment options that can help them stabilize and cope with post-traumatic stress disorder (PTSD) in their everyday life. Guided Imagery and Music (GIM) has improved psychological health for clinical populations...... the suitability of chosen instruments to measure reduction of PTSD symptoms in refugees. Sixteen adult refugees with PTSD were enrolled and they all completed 16 one-hour individual sessions. Pre-post measures of PTSD symptoms, sleep quality, well-being and social function demonstrated significant changes...

  19. Characterization of the onboard imaging unit for the first clinical magnetic resonance image guided radiation therapy system

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yanle, E-mail: Hu.Yanle@mayo.edu [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 and Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, Arizona 85054 (United States); Rankine, Leith; Green, Olga L.; Kashani, Rojano; Li, H. Harold; Li, Hua; Rodriguez, Vivian; Santanam, Lakshmi; Wooten, H. Omar; Mutic, Sasa [Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Nana, Roger; Shvartsman, Shmaryu; Victoria, James; Dempsey, James F. [ViewRay, Inc., Oakwood Village, Ohio 44146 (United States)

    2015-10-15

    Purpose: To characterize the performance of the onboard imaging unit for the first clinical magnetic resonance image guided radiation therapy (MR-IGRT) system. Methods: The imaging performance characterization included four components: ACR (the American College of Radiology) phantom test, spatial integrity, coil signal to noise ratio (SNR) and uniformity, and magnetic field homogeneity. The ACR phantom test was performed in accordance with the ACR phantom test guidance. The spatial integrity test was evaluated using a 40.8 × 40.8 × 40.8 cm{sup 3} spatial integrity phantom. MR and computed tomography (CT) images of the phantom were acquired and coregistered. Objects were identified around the surfaces of 20 and 35 cm diameters of spherical volume (DSVs) on both the MR and CT images. Geometric distortion was quantified using deviation in object location between the MR and CT images. The coil SNR test was performed according to the national electrical manufacturers association (NEMA) standards MS-1 and MS-9. The magnetic field homogeneity test was measured using field camera and spectral peak methods. Results: For the ACR tests, the slice position error was less than 0.10 cm, the slice thickness error was less than 0.05 cm, the resolved high-contrast spatial resolution was 0.09 cm, the resolved low-contrast spokes were more than 25, the image intensity uniformity was above 93%, and the percentage ghosting was less than 0.22%. All were within the ACR recommended specifications. The maximum geometric distortions within the 20 and 35 cm DSVs were 0.10 and 0.18 cm for high spatial resolution three-dimensional images and 0.08 and 0.20 cm for high temporal resolution two dimensional cine images based on the distance-to-phantom-center method. The average SNR was 12.0 for the body coil, 42.9 for the combined torso coil, and 44.0 for the combined head and neck coil. Magnetic field homogeneities at gantry angles of 0°, 30°, 60°, 90°, and 120° were 23.55, 20.43, 18.76, 19

  20. Relationship between noninvasive scores of nonalcoholic fatty liver disease and nuclear magnetic resonance lipoprotein abnormalities: A focus on atherogenic dyslipidemia.

    Science.gov (United States)

    Amor, Antonio J; Pinyol, Montserrat; Solà, Elsa; Catalan, Marta; Cofán, Montserrat; Herreras, Zoe; Amigó, Nuria; Gilabert, Rosa; Sala-Vila, Aleix; Ros, Emilio; Ortega, Emilio

    Nonalcoholic fatty liver disease (NAFLD) is an emerging, highly prevalent, cardiovascular risk factor, and lipoprotein proatherogenic disturbances likely explain a large part of this risk. However, information regarding associations between detailed nuclear magnetic resonance (NMR) lipoprotein changes and noninvasive NAFLD scores is lacking. The objective of the study was to investigate the NMR-assessed atherogenic lipoprotein profile according to noninvasive NAFLD status. Lipoprotein profiles by NMR spectroscopy and NAFLD status by fatty liver index (FLI) and Gholam's models. We assessed 173 participants (55% males), mean age 60.8 ± 7.8 years, 87% overweight/obese, 53% with diabetes. An FLI 60 was found in 32, 50, and 91 participants, respectively. Individuals with FLI >60 had lower high-density lipoprotein (HDL)-cholesterol (P 60, respectively). Conversely, although total HDL particle number did not differ by FLI (P = .377), larger HDL particles (P 60 (vs <60) was associated with a higher proportion of small LDL particles (P = .010) and lower LDL size (19.85 ± 0.34 vs 19.98 ± 0.25 nm; P = .005). Similar findings were found for Gholam's model. Simple and noninvasive NAFLD scores are useful to detect many of the proatherogenic changes (especially in VLDL and HDL), beyond conventional lipids parameters that are common in individuals with this high-risk condition. Copyright © 2017 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  1. Impact of a magnetic resonance imaging-guided treat-to-target strategy on disease activity and progression in patients with rheumatoid arthritis (the IMAGINE-RA trial)

    DEFF Research Database (Denmark)

    Møller-Bisgaard, Signe; Hørslev-Petersen, Kim; Ejbjerg, Bo Jannik

    2015-01-01

    . This demonstrates that additional methods for prognostication and monitoring of the disease activity are needed. Bone marrow edema (BME) detected by magnetic resonance imaging (MRI) has proved to be an independent predictor of subsequent radiographic progression. Guiding the treatment based on the presence....../absence of BME may therefore be clinically beneficial. We present the design of a randomized controlled trial (RCT) aiming to evaluate whether an MRI-guided treatment strategy compared to a conventional treatment strategy in anti-CCP-positive erosive RA is better to prevent progression of erosive joint damage...... swollen joints and treatment with synthetic disease-modifying antirheumatic drugs (DMARDs) will be included. Patients will be randomized to either a treatment strategy based on conventional laboratory and clinical examinations (control group) or a treatment strategy based on conventional laboratory...

  2. Evaluation of epileptogenic focus in temporal lobe: correlation between ictal brain SPECT, magnetic resonance imaging and magnetic resonance spectroscopy; Avaliacao de foco epileptogenico do lobo temporal: correlacao entre SPECT ictal, ressonancia magnetica e ressonancia magnetica com espectroscopia de protons

    Energy Technology Data Exchange (ETDEWEB)

    Diegues, Maria Elena Martins [Hospital Universitario Clementino Fraga Filho, Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear]. E-mail: emartyns@terra.com.br; Pellini, Marcos Pinto; Alves-Leon, Soniza Vieira [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Medicina; Domingues, Romeu Cortes [Clinica de Diagnostico por Imagem (CDPI), Rio de Janeiro, RJ (Brazil)

    2004-02-01

    The purpose of this study was to determine the degree of concordance between radiological and radioisotopic methods and, if positive, to evaluate the usefulness of ictal SPECT in the localization of the epileptogenic focus. Ictal brain SPECT, magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) were performed on six patients with refractory temporal lobe epilepsy. Ictal SPECT was performed after withdrawal of the anti-epileptogenic drugs during video-EEG monitoring, using {sup 99m}Tc-ECD, administered to patients at the time of the ictus. MRI was performed in T1, T2 and FLAIR sequences and MRS was obtained using the PRESS technique, with a single voxel positioned in both hippocampi. The statistical analysis included the determination of the values of Kappa (k), standard error (se) and significance level (p) for the lateralization of the ictal focus. The analysis of all findings was based on EEG localization of the ictal discharge, seizure duration (109-280 s; 152 s average) and time of radiotracer injection (30-262 s; 96 s average). We obtained correlated data in four patients (67 per cent) and values of k = 0.67, se = 0.38, and p 0.041. We concluded that there is a concordance between ictal SPECT, MRI and MRS data and the usefulness of the radioisotopic procedure is related to a non diagnostic EEG and when there is a discordant or misleading diagnosis after a comparative analysis of EEG and MRS. (author)

  3. Fluorescence and Magnetic Resonance Dual-Modality Imaging-Guided Photothermal and Photodynamic Dual-Therapy with Magnetic Porphyrin-Metal Organic Framework Nanocomposites

    Science.gov (United States)

    Zhang, Hui; Li, Yu-Hao; Chen, Yang; Wang, Man-Man; Wang, Xue-Sheng; Yin, Xue-Bo

    2017-03-01

    Phototherapy shows some unique advantages in clinical application, such as remote controllability, improved selectivity, and low bio-toxicity, than chemotherapy. In order to improve the safety and therapeutic efficacy, imaging-guided therapy seems particularly important because it integrates visible information to speculate the distribution and metabolism of the probe. Here we prepare biocompatible core-shell nanocomposites for dual-modality imaging-guided photothermal and photodynamic dual-therapy by the in situ growth of porphyrin-metal organic framework (PMOF) on Fe3O4@C core. Fe3O4@C core was used as T2-weighted magnetic resonance (MR) imaging and photothermal therapy (PTT) agent. The optical properties of porphyrin were well remained in PMOF, and PMOF was therefore selected for photodynamic therapy (PDT) and fluorescence imaging. Fluorescence and MR dual-modality imaging-guided PTT and PDT dual-therapy was confirmed with tumour-bearing mice as model. The high tumour accumulation of Fe3O4@C@PMOF and controllable light excitation at the tumour site achieved efficient cancer therapy, but low toxicity was observed to the normal tissues. The results demonstrated that Fe3O4@C@PMOF was a promising dual-imaging guided PTT and PDT dual-therapy platform for tumour diagnosis and treatment with low cytotoxicity and negligible in vivo toxicity.

  4. The Family Physician’s Perceived Role in Preventing and Guiding Hospital Admissions at the End of Life: A Focus Group Study

    Science.gov (United States)

    Reyniers, Thijs; Houttekier, Dirk; Pasman, H. Roeline; Stichele, Robert Vander; Cohen, Joachim; Deliens, Luc

    2014-01-01

    PURPOSE Family physicians play a pivotal role in providing end-of-life care and in enabling terminally ill patients to die in familiar surroundings. The purpose of this study was to explore the family physicians’ perceptions of their role and the difficulties they have in preventing and guiding hospital admissions at the end of life. METHODS Five focus groups were held with family physicians (N= 39) in Belgium. Discussions were transcribed verbatim and analyzed using a constant comparative approach. RESULTS Five key roles in preventing and guiding hospital admissions at the end of life were identified: as a care planner, anticipating future scenarios; as an initiator of decisions in acute situations, mostly in an advisory manner; as a provider of end-of-life care, in which competency and attitude is considered important; as a provider of support, particularly by being available during acute situations; and as a decision maker, taking overall responsibility. CONCLUSIONS Family physicians face many different and complex roles and difficulties in preventing and guiding hospital admissions at the end of life. Enhancing the family physician’s role as a gatekeeper to hospital services, offering the physicians more end-of-life care training, and developing or expanding initiatives to support them could contribute to a lower proportion of hospital admissions at the end of life. PMID:25354408

  5. A guide to statistical analysis in microbial ecology: a community-focused, living review of multivariate data analyses.

    Science.gov (United States)

    Buttigieg, Pier Luigi; Ramette, Alban

    2014-12-01

    The application of multivariate statistical analyses has become a consistent feature in microbial ecology. However, many microbial ecologists are still in the process of developing a deep understanding of these methods and appreciating their limitations. As a consequence, staying abreast of progress and debate in this arena poses an additional challenge to many microbial ecologists. To address these issues, we present the GUide to STatistical Analysis in Microbial Ecology (GUSTA ME): a dynamic, web-based resource providing accessible descriptions of numerous multivariate techniques relevant to microbial ecologists. A combination of interactive elements allows users to discover and navigate between methods relevant to their needs and examine how they have been used by others in the field. We have designed GUSTA ME to become a community-led and -curated service, which we hope will provide a common reference and forum to discuss and disseminate analytical techniques relevant to the microbial ecology community. © 2014 The Authors. FEMS Microbiology Ecology published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.

  6. Gleason Score Determination with Transrectal Ultrasound-Magnetic Resonance Imaging Fusion Guided Prostate Biopsies--Are We Gaining in Accuracy?

    Science.gov (United States)

    Lanz, Camille; Cornud, François; Beuvon, Frédéric; Lefèvre, Arnaud; Legmann, Paul; Zerbib, Marc; Delongchamps, Nicolas Barry

    2016-01-01

    We evaluated the accuracy of prostate magnetic resonance imaging- transrectal ultrasound targeted biopsy for Gleason score determination. We selected 125 consecutive patients treated with radical prostatectomy for a clinically localized prostate cancer diagnosed on magnetic resonance imaging-transrectal ultrasound targeted biopsy and/or systematic biopsy. On multiparametric magnetic resonance imaging each suspicious area was graded according to PI-RADS™ score. A correlation analysis between multiparametric magnetic resonance imaging and pathological findings was performed. Factors associated with determining the accuracy of Gleason score on targeted biopsy were statistically assessed. Pathological analysis of radical prostatectomy specimens detected 230 tumor foci. Multiparametric magnetic resonance imaging detected 151 suspicious areas. Of these areas targeted biopsy showed 126 cancer foci in 115 patients, and detected the index lesion in all of them. The primary Gleason grade, secondary Gleason grade and Gleason score of the 126 individual tumors were determined accurately in 114 (90%), 75 (59%) and 85 (67%) cases, respectively. Maximal Gleason score was determined accurately in 80 (70%) patients. Gleason score determination accuracy on targeted biopsy was significantly higher for low Gleason and high PI-RADS score tumors. Magnetic resonance imaging-transrectal ultrasound targeted biopsy allowed for an accurate estimation of Gleason score in more than two-thirds of patients. Gleason score misclassification was mostly due to a lack of accuracy in the determination of the secondary Gleason grade. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  7. Non-Invasive Targeted Peripheral Nerve Ablation Using 3D MR Neurography and MRI-Guided High-Intensity Focused Ultrasound (MR-HIFU) : Pilot Study in a Swine Model

    NARCIS (Netherlands)

    Huisman, Merel; Staruch, Robert M; Ladouceur-Wodzak, Michelle; van den Bosch, Maurice A; Burns, Dennis K; Chhabra, Avneesh; Chopra, Rajiv

    2015-01-01

    PURPOSE: Ultrasound (US)-guided high intensity focused ultrasound (HIFU) has been proposed for noninvasive treatment of neuropathic pain and has been investigated in in-vivo studies. However, ultrasound has important limitations regarding treatment guidance and temperature monitoring. Magnetic

  8. Towards real-time cardiovascular magnetic resonance-guided transarterial aortic valve implantation: In vitro evaluation and modification of existing devices

    Directory of Open Access Journals (Sweden)

    Ladd Mark E

    2010-10-01

    Full Text Available Abstract Background Cardiovascular magnetic resonance (CMR is considered an attractive alternative for guiding transarterial aortic valve implantation (TAVI featuring unlimited scan plane orientation and unsurpassed soft-tissue contrast with simultaneous device visualization. We sought to evaluate the CMR characteristics of both currently commercially available transcatheter heart valves (Edwards SAPIEN™, Medtronic CoreValve® including their dedicated delivery devices and of a custom-built, CMR-compatible delivery device for the Medtronic CoreValve® prosthesis as an initial step towards real-time CMR-guided TAVI. Methods The devices were systematically examined in phantom models on a 1.5-Tesla scanner using high-resolution T1-weighted 3D FLASH, real-time TrueFISP and flow-sensitive phase-contrast sequences. Images were analyzed for device visualization quality, device-related susceptibility artifacts, and radiofrequency signal shielding. Results CMR revealed major susceptibility artifacts for the two commercial delivery devices caused by considerable metal braiding and precluding in vivo application. The stainless steel-based Edwards SAPIEN™ prosthesis was also regarded not suitable for CMR-guided TAVI due to susceptibility artifacts exceeding the valve's dimensions and hindering an exact placement. In contrast, the nitinol-based Medtronic CoreValve® prosthesis was excellently visualized with delineation even of small details and, thus, regarded suitable for CMR-guided TAVI, particularly since reengineering of its delivery device toward CMR-compatibility resulted in artifact elimination and excellent visualization during catheter movement and valve deployment on real-time TrueFISP imaging. Reliable flow measurements could be performed for both stent-valves after deployment using phase-contrast sequences. Conclusions The present study shows that the Medtronic CoreValve® prosthesis is potentially suited for real-time CMR-guided placement

  9. Magnetic resonance tomography-guided interventional procedure for diagnosis of prostate cancer; MRT-gezielte interventionelle Verfahren zur Abklaerung des Prostatakarzinoms

    Energy Technology Data Exchange (ETDEWEB)

    Schernthaner, M.; Helbich, T.H.; Fueger, B.J.; Memarsadeghi, M.; Stiglbauer, A.; Linhart, H.G.; Doan, A.; Pinker, K.; Brader, P. [Medizinische Universitaet Wien, Univ.-Klinik fuer Radiodiagnostik, Division fuer Molekulare und Gender-Bildgebung, Wien (Austria); Margreiter, M. [Medizinische Universitaet Wien, Univ.-Klinik fuer Urologie, Wien (Austria)

    2011-11-15

    In recent years magnetic resonance imaging (MRI) has been increasingly established in the diagnosis of prostate cancer in addition to transrectal ultrasonography (TRUS). The use of T2-weighted imaging allows an exact delineation of the zonal anatomy of the prostate and its surrounding structures. Other MR imaging tools, such as dynamic contrast-enhanced T1-weighted imaging or diffusion-weighted imaging allow an inference of the biochemical characteristics (multiparametric MRI). Prostate cancer, which could only be diagnosed using MR imaging or lesions suspected as being prostate cancer, which are localized in the anterior aspect of the prostate and were missed with repetitive TRUS biopsy, need to undergo MR guided biopsy. Recent studies have shown a good correlation between MR imaging and histopathology of specimens collected by MR-guided biopsy. Improved lesion targeting is therefore possible with MR-guided biopsy. So far data suggest that MR-guided biopsy of the prostate is a promising alternative diagnostic tool to TRUS-guided biopsy. (orig.) [German] Neben dem transrektalen Ultraschall (TRUS) hat sich in den letzten Jahren die MRT als nichtinvasive Methode zur Bildgebung von Prostatatumoren etabliert. Mittels T2-gewichteter Sequenzen ist eine exakte anatomische Darstellung der Prostata und ihrer umliegenden Strukturen moeglich. Andere MRT-Techniken ermoeglichen Rueckschluesse auf das biologische Verhalten des Tumors: dynamische kontrastmittelverstaerkte T1-gewichtete Sequenzen zur Darstellung der Angiogenese, diffusionsgewichtete Aufnahmen zur Beurteilung der Zelldichte und die Spektroskopie zur Bestimmung von Gewebemetaboliten wie Cholin und Kreatin (multiparametrische Bildgebung). Prostatatumoren, die nur mittels MRT nachweisbar sind oder verdaechtige Tumoren, die hauptsaechlich anterior in der Prostata lokalisiert sind und in wiederholten TRUS-gezielten Biopsien verfehlt wurden, benoetigen eine MRT-gezielte Biopsie zur Diagnosesicherung. Die bisherigen

  10. Eliminating the use of intravenous glass bottles using a FOCUS-PDCA model and providing a practical stability reference guide.

    Science.gov (United States)

    Maraiki, Fatma; Farooq, Faiyaz; Ahmed, Mohamed

    2016-08-01

    To identify the intravenous (IV) medications that are prepared in glass bottles at the institution and establish which of these medications can be prepared in flexible IV bags such as polyvinyl chloride (PVC) or non-PVC instead of glass bottles. The cost implication of switching from glass bottles to flexible IV bags was calculated. A study using FOCUS-PDCA model to identify IV medications prepared in glass bottles and establish which of these medications could be prepared in IV bags (PVC or non-PVC). The cost impact of switching from glass bottles to IV plastic bags (including PVC or non-PVC) was calculated. The stability data obtained were used as a reference for updating pharmacy internal IV preparation charts. A total of 17 IV medications were found to be prepared in IV glass bottles. Of these 17 medications, only 8 (47%) were prepared in IV glass bottles due to incompatibility with PVC bags. For 7 (41%) of the medications, of which 6 were monoclonal antibodies (MABs), the reason for preparation in glass bottles was unclear as these medications are compatible with either PVC or non-PVC or both. The potential cost savings associated with switching all of the identified medications to IV plastic bags (either non-PVC or PVC) exceeded $200 000. The elimination of glass bottles within the institution resulted in a significant cost saving. The use of FOCUS-PDCA model can help healthcare institution achieve significant improvements in process and realize significant cost savings. © 2016 Royal Pharmaceutical Society.

  11. Numerical optimization of a three-channel radiofrequency coil for open, vertical-field, MR-guided, focused ultrasound surgery using the hybrid method of moment/finite difference time domain method.

    Science.gov (United States)

    Xin, Xuegang; Wang, Di; Han, Jijun; Feng, Yanqiu; Feng, Qianjin; Chen, Wufan

    2012-07-01

    The numerical optimization of a three-channel radiofrequency (RF) coil with a physical aperture for the open, vertical-field, MR-guided, focused ultrasound surgery (MRgFUS) system using the hybrid method of moment (MoM)/finite difference time domain (FDTD) method is reported. The numerical simulation of the current density distribution on an RF coil with a complicated irregular structure was performed using MoM. The electromagnetic field simulation containing the full coil-tissue interactions within the region of interest was accomplished using the FDTD method. Huygens' equivalent box with six surfaces smoothly connected the MoM and FDTD method. An electromagnetic model of the human pelvic region was reconstructed and loaded in the FDTD zone to optimize the three-channel RF coil and compensate for the lower sensitivity at the vertical field. In addition, the numerical MoM was used to model the resonance, decoupling and impedance matching of the RF coil in compliance with engineering practices. A prototype RF coil was constructed to verify the simulation results. The results demonstrate that the signal-to-noise ratio and the homogeneity of the B(1) field were both greatly improved compared with previously published results. Copyright © 2011 John Wiley & Sons, Ltd.

  12. Contrast-Enhanced Dynamic MR Imaging of Uterine Fibroids as a Potential Predictor of Patient Eligibility for MR Guided Focused Ultrasound (MRgFUS Treatment for Symptomatic Uterine Fibroids

    Directory of Open Access Journals (Sweden)

    Sang-Wook Yoon

    2010-01-01

    Full Text Available Magnetic resonance-guided focused ultrasound surgery (MRgFUS is a non-invasive treatment approach for symptomatic uterine fibroids. One imaging characteristic considered in selecting patients who may benefit from MRgFUS of their uterine fibroids is the signal intensity of the fibroid compared with surrounding myometrium on T2-weighted MR images. Previous reports suggest that hyper-intense fibroids are less amenable to MRgFUS compared with iso- or hypo-intense fibroids. In this case study, we utilized contrast-enhanced dynamic MR imaging to further characterize the vascularity of a hyper-intense fibroid. Based on the results of dynamic T1-weighted contrast-enhanced images, we assumed that the hyper-intense appearance resulted from high fluid content rather than high vascularity and predicted that the fibroid would respond to MRgFUS. The patient underwent the MRgFUS without complication and reported significant decrease in fibroid symptoms at 3 and 12 months post-treatment. This case suggests that pre-treatment dynamic contrast-enhanced imaging used in conjunction with T2-weighted imaging may improve the criteria for selecting uterine fibroids amenable to treatment with MRgFUS, potentially leading to improved patient outcomes.

  13. Three-dimensional spatial and temporal temperature control with MR thermometry-guided focused ultrasound (MRgHIFU).

    Science.gov (United States)

    Mougenot, Charles; Quesson, Bruno; de Senneville, Baudouin Denis; de Oliveira, Philippe Lourenco; Sprinkhuizen, Sara; Palussière, Jean; Grenier, Nicolas; Moonen, Chrit T W

    2009-03-01

    High-intensity focused ultrasound (HIFU) is an efficient noninvasive technique for local heating. Using MRI thermal maps, a proportional, integral, and derivative (PID) automatic temperature control was previously applied at the focal point, or at several points within a plane perpendicular to the beam axis using a multispiral focal point trajectory. This study presents a flexible and rapid method to extend the spatial PID temperature control to three dimensions during each MR dynamic. The temperature in the complete volume is regulated by taking into account the overlap effect of nearby sonication points, which tends to enlarge the heated area along the beam axis. Volumetric temperature control in vitro in gel and in vivo in rabbit leg muscle was shown to provide temperature control with a precision close to that of the temperature MRI measurements. The proposed temperature control ensures heating throughout the volume of interest of up to 1 ml composed of 287 voxels with 95% of the energy deposited within its boundaries and reducing the typical average temperature overshoot to 1 degrees C.

  14. Magnetic resonance imaging-guided core needle breast biopsies resulting in high-risk histopathologic findings: upstage frequency and lesion characteristics.

    Science.gov (United States)

    Weinfurtner, R Jared; Patel, Bhavika; Laronga, Christine; Lee, Marie C; Falcon, Shannon L; Mooney, Blaise P; Yue, Binglin; Drukteinis, Jennifer S

    2015-06-01

    Analysis of magnetic resonance imaging-guided breast biopsies yielding high-risk histopathologic features at a single institution found an overall upstage rate to malignancy of 14% at surgical excision. All upstaged lesions were associated with atypical ductal hyperplasia. Flat epithelial atypia and atypical lobular hyperplasia alone or with lobular carcinoma in situ were not associated with an upstage to malignancy. The purpose of the present study w as to determine the malignancy upstage rates and imaging features of high-risk histopathologic findings resulting from magnetic resonance imaging (MRI)-guided core needle breast biopsies. These features include atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), flat epithelial atypia (FEA), and lobular carcinoma in situ (LCIS). A retrospective medical record review was performed on all MRI-guided core needle breast biopsies at a single institution from June 1, 2007 to December 1, 2013 to select biopsies yielding high-risk histopathologic findings. The patient demographics, MRI lesion characteristics, and histopathologic features at biopsy and surgical excision were analyzed. A total of 257 MRI-guided biopsies had been performed, and 50 yielded high-risk histopathologic features (19%). Biopsy site and surgical excision site correlation was confirmed in 29 of 50 cases. Four of 29 lesions (14%) were upstaged: 1 case to invasive ductal carcinoma and 3 cases to ductal carcinoma in situ. ADH alone had an overall upstage rate of 7% (1 of 14), mixed ADH/ALH a rate of 75% (3 of 4), ALH alone or with LCIS a rate of 0% (0 of 7), and FEA a rate of 0% (0 of 4). Only mixed ADH/ALH had a statistically significant upstage rate to malignancy compared with the other high-risk histopathologic subtypes combined. No specific imaging characteristics on MRI were associated with an upstage to malignancy on the statistical analysis. MRI-guided breast biopsies yielding high-risk histopathologic features were associated with

  15. Assessment of Gold Nanoparticle-Mediated-Enhanced Hyperthermia Using MR-Guided High-Intensity Focused Ultrasound Ablation Procedure.

    Science.gov (United States)

    Devarakonda, Surendra B; Myers, Matthew R; Lanier, Mathew; Dumoulin, Charles; Banerjee, Rupak K

    2017-04-12

    High-intensity focused ultrasound (HIFU) has gained increasing popularity as a noninvasive therapeutic procedure to treat solid tumors. However, collateral damage due to the use of high acoustic powers during HIFU procedures remains a challenge. The objective of this study is to assess the utility of using gold nanoparticles (gNPs) during HIFU procedures to locally enhance heating at low powers, thereby reducing the likelihood of collateral damage. Phantoms containing tissue-mimicking material (TMM) and physiologically relevant concentrations (0%, 0.0625%, and 0.125%) of gNPs were fabricated. Sonications at acoustic powers of 10, 15, and 20 W were performed for a duration of 16 s using an MR-HIFU system. Temperature rises and lesion volumes were calculated and compared for phantoms with and without gNPs. For an acoustic power of 10 W, the maximum temperature rise increased by 32% and 43% for gNPs concentrations of 0.0625% and 0.125%, respectively, when compared to the 0% gNPs concentration. For the power of 15 W, a lesion volume of 0, 44.5 ± 7, and 63.4 ± 32 mm3 was calculated for the gNPs concentration of 0%, 0.0625%, and 0.125%, respectively. For a power of 20 W, it was found that the lesion volume doubled and tripled for concentrations of 0.0625% and 0.125% gNPs, respectively, when compared to the concentration of 0% gNPs. We conclude that gNPs have the potential to locally enhance the heating and reduce damage to healthy tissue during tumor ablation using HIFU.

  16. Meta-analyses and Forest plots using a microsoft excel spreadsheet: step-by-step guide focusing on descriptive data analysis

    Directory of Open Access Journals (Sweden)

    Neyeloff Jeruza L

    2012-01-01

    Full Text Available Abstract Background Meta-analyses are necessary to synthesize data obtained from primary research, and in many situations reviews of observational studies are the only available alternative. General purpose statistical packages can meta-analyze data, but usually require external macros or coding. Commercial specialist software is available, but may be expensive and focused in a particular type of primary data. Most available softwares have limitations in dealing with descriptive data, and the graphical display of summary statistics such as incidence and prevalence is unsatisfactory. Analyses can be conducted using Microsoft Excel, but there was no previous guide available. Findings We constructed a step-by-step guide to perform a meta-analysis in a Microsoft Excel spreadsheet, using either fixed-effect or random-effects models. We have also developed a second spreadsheet capable of producing customized forest plots. Conclusions It is possible to conduct a meta-analysis using only Microsoft Excel. More important, to our knowledge this is the first description of a method for producing a statistically adequate but graphically appealing forest plot summarizing descriptive data, using widely available software.

  17. Meta-analyses and Forest plots using a microsoft excel spreadsheet: step-by-step guide focusing on descriptive data analysis.

    Science.gov (United States)

    Neyeloff, Jeruza L; Fuchs, Sandra C; Moreira, Leila B

    2012-01-20

    Meta-analyses are necessary to synthesize data obtained from primary research, and in many situations reviews of observational studies are the only available alternative. General purpose statistical packages can meta-analyze data, but usually require external macros or coding. Commercial specialist software is available, but may be expensive and focused in a particular type of primary data. Most available softwares have limitations in dealing with descriptive data, and the graphical display of summary statistics such as incidence and prevalence is unsatisfactory. Analyses can be conducted using Microsoft Excel, but there was no previous guide available. We constructed a step-by-step guide to perform a meta-analysis in a Microsoft Excel spreadsheet, using either fixed-effect or random-effects models. We have also developed a second spreadsheet capable of producing customized forest plots. It is possible to conduct a meta-analysis using only Microsoft Excel. More important, to our knowledge this is the first description of a method for producing a statistically adequate but graphically appealing forest plot summarizing descriptive data, using widely available software.

  18. An intelligent nanotheranostic agent for targeting, redox-responsive ultrasound imaging, and imaging-guided high-intensity focused ultrasound synergistic therapy.

    Science.gov (United States)

    Wang, Xia; Chen, Hangrong; Zhang, Kun; Ma, Ming; Li, Faqi; Zeng, Deping; Zheng, Shuguang; Chen, Yu; Jiang, Lixin; Xu, Huixiong; Shi, Jianlin

    2014-04-09

    A novel multifunctional nanotheranostic agent with targeting, redox-responsive ultrasound imaging and ultrasound imaging-guided high-intensity focused ultrasound (HIFU) therapy (MSNC-PEG-HA(SS)-PFH, abbreviated as MPH(SS)-PFH) capabilities is developed. The redox-responsive guest molecule release and ultrasound imaging functions can be both integrated in such a "smart" theranostic agent, which is accomplished by the redox-triggered transition from the crosslinking state to retrocrosslinking state of the grafted polyethylene glycol-disulfide hyaluronic acid molecules on the particle surface when reaching a reducing environment in vitro. More importantly, under the tailored ultrasound imaging guiding, in vivo Hela tumor-bearing nude mice can be thoroughly and spatial-accurately ablated during HIFU therapy, due to the targeted accumulation, responsive ultrasound imaging guidance and the synergistic ablation functions of nanotheranostic agent MPH(SS)-PFH in the tumors. This novel multifunctional nano-platform can serve as a promising candidate for further studies on oncology therapy, due to its high stability, responsive and indicative ultrasound imaging of tumors, and enhanced HIFU therapeutic efficiency and spatial accuracy under ultrasound-guidance. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Clinical management of electromagnetic interferences in patients with pacemakers and implantable cardioverter-defibrillators: review of the literature and focus on magnetic resonance conditional devices.

    Science.gov (United States)

    Corzani, Alessandro; Ziacchi, Matteo; Biffi, Mauro; Allaria, Luca; Diemberger, Igor; Martignani, Cristian; Bratten, Tara; Gardini, Beatrice; Boriani, Giuseppe

    2015-10-01

    The number of cardiac implantable electronic devices (CIEDs) has greatly increased in the last 10 years. Many electronic devices used in daily activities generate electromagnetic interferences (EMIs) that can interact with CIEDs. In clinical practice, it is very important to know the potential sources of EMIs and their effect on CIEDs in order to understand how to manage or mitigate them. A very important source of EMI is magnetic resonance (MR), which is considered nowadays the diagnostic gold standard for different anatomical districts. In this review, we focused on the effects of EMI on CIEDs and on the clinical management. Moreover, we made a clarification about MR and CIEDs.In patients with CIEDs, EMIs may cause potentially serious and even life-threatening complications (inappropriate shocks, device malfunctions, inhibition of pacing in pacemaker-dependent patients) and may rarely dictate device replacement. The association of inappropriate shocks with increased mortality highlights the importance of minimizing the occurrence of EMI. Adequate advice and recommendations about the correct management of EMIs in patients with CIEDs are required to avoid all complications during hospitalization and in daily life. Furthermore, the article focused on actual management about MR and CIEDs.

  20. Quantifying stickiness: thermodynamic characterization of intramolecular domain interactions to guide the design of forster resonance energy transfer sensors

    NARCIS (Netherlands)

    Lindenburg, L.H.; Malisauskas, M.; Sips, T.; Oppen, L.M.P.E. van; Wijnands, S.P.; Graaf, S.F.J. van de; Merkx, M.

    2014-01-01

    The introduction of weak, hydrophobic interactions between fluorescent protein domains (FPs) can substantially increase the dynamic range (DR) of Forster resonance energy transfer (FRET)-based sensor systems. Here we report a comprehensive thermodynamic characterization of the stability of a range

  1. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach.

    Science.gov (United States)

    Salamon, Johannes; Hofmann, Martin; Jung, Caroline; Kaul, Michael Gerhard; Werner, Franziska; Them, Kolja; Reimer, Rudolph; Nielsen, Peter; Vom Scheidt, Annika; Adam, Gerhard; Knopp, Tobias; Ittrich, Harald

    2016-01-01

    In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI) / magnetic resonance imaging (MRI) road map approach and an MPI-guided approach using a blood pool tracer. A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superparamagnetic iron oxide nanoparticles (MM4) was equipped with bimodal fiducial markers for co-registration in preclinical 7T MRI and MPI. In-vitro angioplasty was performed inflating the balloon with saline or MM4. MPI data were acquired using a field of view of 37.3×37.3×18.6 mm3 and a frame rate of 46 volumes/sec. Analysis of the magnetic lacquer-marks on the devices were performed with electron microscopy, atomic absorption spectrometry and micro-computed tomography. Magnetic marks allowed for MPI/MRI guidance of interventional devices. Bimodal fiducial markers enable MPI/MRI image fusion for MRI based roadmapping. MRI roadmapping and the blood pool tracer approach facilitate MPI real time monitoring of in-vitro angioplasty. Successful angioplasty was verified with MPI and MRI. Magnetic marks consist of micrometer sized ferromagnetic plates mainly composed of iron and iron oxide. 4D real time MP imaging, tracking and guiding of endovascular instruments and in-vitro angioplasty is feasible. In addition to an approach that requires a blood pool tracer, MRI based roadmapping might emerge as a promising tool for radiation free 4D MPI-guided interventions.

  2. Magnetic Particle / Magnetic Resonance Imaging: In-Vitro MPI-Guided Real Time Catheter Tracking and 4D Angioplasty Using a Road Map and Blood Pool Tracer Approach.

    Directory of Open Access Journals (Sweden)

    Johannes Salamon

    Full Text Available In-vitro evaluation of the feasibility of 4D real time tracking of endovascular devices and stenosis treatment with a magnetic particle imaging (MPI / magnetic resonance imaging (MRI road map approach and an MPI-guided approach using a blood pool tracer.A guide wire and angioplasty-catheter were labeled with a thin layer of magnetic lacquer. For real time MPI a custom made software framework was developed. A stenotic vessel phantom filled with saline or superparamagnetic iron oxide nanoparticles (MM4 was equipped with bimodal fiducial markers for co-registration in preclinical 7T MRI and MPI. In-vitro angioplasty was performed inflating the balloon with saline or MM4. MPI data were acquired using a field of view of 37.3×37.3×18.6 mm3 and a frame rate of 46 volumes/sec. Analysis of the magnetic lacquer-marks on the devices were performed with electron microscopy, atomic absorption spectrometry and micro-computed tomography.Magnetic marks allowed for MPI/MRI guidance of interventional devices. Bimodal fiducial markers enable MPI/MRI image fusion for MRI based roadmapping. MRI roadmapping and the blood pool tracer approach facilitate MPI real time monitoring of in-vitro angioplasty. Successful angioplasty was verified with MPI and MRI. Magnetic marks consist of micrometer sized ferromagnetic plates mainly composed of iron and iron oxide.4D real time MP imaging, tracking and guiding of endovascular instruments and in-vitro angioplasty is feasible. In addition to an approach that requires a blood pool tracer, MRI based roadmapping might emerge as a promising tool for radiation free 4D MPI-guided interventions.

  3. Droplet-based label-free detection system based on guided-mode resonance and electrowetting-on-dielectric for concentration measurement

    Science.gov (United States)

    Wang, Ying-Bin; Su, Lin-Yun; Fu, Ching-Shu; Huang, Cheng-Sheng; Hsu, Wensyang

    2017-05-01

    We demonstrate a digital microfluidic system with an on-chip detection capability that is based on a guided-mode resonance filter (GMRF). Versatile droplet manipulation was achieved through the electrowetting-on-dielectric (EWOD) technique. GMRF was fabricated through replica molding and soft lithography, and the EWOD chip was fabricated through a typical photolithography process. Droplets measuring 1.125 µL were used to demonstrate merging, mixing, and cutting, and to achieve twofold and Threefold dilutions, and were then transported to the GMRF region for concentration measurement. The bulk sensitivity of GMRF is approximately 90 nm RIU-1 [17494 nm/(g/L)], resulting in a minimum detectable concentration of 4.66 × 10-5 g/L for a sucrose solution.

  4. Localized delivery of doxorubicin in vivo from polymer-modified thermosensitive liposomes with MR-guided focused ultrasound-mediated heating.

    Science.gov (United States)

    Ta, Terence; Bartolak-Suki, Elizabeth; Park, Eun-Joo; Karrobi, Kavon; McDannold, Nathan J; Porter, Tyrone M

    2014-11-28

    Thermosensitive liposomes have emerged as a viable strategy for localized delivery and triggered release of chemotherapy. MR-guided focused ultrasound (MRgFUS) has the capability of heating tumors in a controlled manner, and when combined with thermosensitive liposomes can potentially reduce tumor burden in vivo. However, the impact of this drug delivery strategy has rarely been investigated. We have developed a unique liposome formulation modified with p(NIPAAm-co-PAA), a polymer that confers sensitivity to both temperature and pH. These polymer-modified thermosensitive liposomes (PTSL) demonstrated sensitivity to focused ultrasound, and required lower thermal doses and were more cytotoxic than traditional formulations in vitro. A set of acoustic parameters characterizing optimal release from PTSL in vitro was applied in the design of a combined MRgFUS/PTSL delivery platform. This platform more effectively reduced tumor burden in vivo when compared to free drug and traditional formulations. Histological analysis indicated greater tumor penetration, more extensive ECM remodeling, and greater cell destruction in tumors administered PTSL, correlating with improved response to the therapy. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Using the Theory of Planned Behavior to Guide Focus Group Development of Messages Aimed at Increasing Compliance With a Tobacco-Free Policy.

    Science.gov (United States)

    Record, Rachael A; Harrington, Nancy G; Helme, Donald W; Savage, Matthew W

    2018-01-01

    This study details the persuasive message development for a theory-based campaign designed to increase compliance with a university's tobacco-free policy. The theory of planned behavior (TPB) guided message design and evaluation for focus group-tested messages that were adapted to the context of complying with a tobacco-free policy. The study was conducted at a university located in the tobacco belt. Undergraduate focus group participants (n = 65) were mostly male (69%), white (82%), and freshman (62%) who smoked at least 1 cigarette in the last 30 days; on-campus smoking percentages were never/rare (60%), occasionally (23%), and often/frequently (16%). Data analysis used a theoretical thematic approach to identify how the TPB constructs related to perceptions of message effectiveness. Participants responded favorably to attitudinal strategies about health, respect, and university figures; they rejected approaches they considered juvenile and offensive. They also discussed the impact of noncompliance and avoiding overgeneralized statements for addressing subjective norms, suggesting shortening text, adjusting picture location, and emphasizing the importance of compliance to increase perceptions of behavioral control. Applying theory to preexisting messages is challenging. The design approach in this study is an evidence-based strategy that can be used as a universal process for message adaptation. Results offer health promotion suggestions for designing messages aimed at improving undergraduate smokers' willingness to comply with tobacco-free campus policies.

  6. Image-guided high-dose-rate brachytherapy boost to the dominant intraprostatic lesion using multiparametric magnetic resonance imaging including spectroscopy: Results of a prospective study.

    Science.gov (United States)

    Vigneault, Eric; Mbodji, Khaly; Racine, Louis-Gabriel; Chevrette, Eric; Lavallée, Marie-Claude; Martin, André-Guy; Després, Philippe; Beaulieu, Luc

    To evaluate the long-term outcomes of image-guided high-dose-rate (HDR) brachytherapy boost to the dominant intraprostatic lesion (DIL) using multiparametric magnetic resonance imaging (MRI), including spectroscopy (MRI/magnetic resonance spectroscopy [MRS]). Between December 2009 and March 2011, 20 patients with intermediate-risk prostate cancer underwent multiparametric MRI/MRS protocol before treatment. All patients were treated with an external beam radiotherapy dose of 40 Gy, combined with an HDR brachytherapy boost of 15 Gy. Concurrently, the DIL received a boost of 18 Gy. Missing data during followup were handled with multiple imputations. The median followup was 62 months (range, 23-71 months). Six patients (31%) were classified as favorable intermediate risk and 13 patients (69%) as unfavorable intermediate risk. One patient experienced a prostate-specific antigen biochemical failure, and the 5-year biochemical failure-free survival rate was of 94.7%. The mean International Prostate Symptom Score rose from 7, with respect to baseline, to 10.42 1 month after treatment, and rapidly decreased to 6.97 after 3 months. Grade 1, 2, and 3 acute genitourinary toxicities were reported in 13 (68%), 3 (16%), and 1 (5%) patients, respectively. Grade 1 and 2 late genitourinary toxicities were reported in 9 (53%) and 3 (18%) patients, respectively. Only grade 1 acute and late gastrointestinal toxicities were reported in 4 (21%) and 3 (18%) patients, respectively. Delivering an HDR brachytherapy boost to the DIL using image-guided multiparametric MRI/MRS is feasible with good outcomes for biochemical control, acute and late toxicities, and dosimetric constraints for critical organs. Copyright © 2016 American Brachytherapy Society. All rights reserved.

  7. Cervical Gross Tumor Volume Dose Predicts Local Control Using Magnetic Resonance Imaging/Diffusion-Weighted Imaging—Guided High-Dose-Rate and Positron Emission Tomography/Computed Tomography—Guided Intensity Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Dyk, Pawel; Jiang, Naomi; Sun, Baozhou; DeWees, Todd A. [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Fowler, Kathryn J.; Narra, Vamsi [Department of Diagnostic Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Garcia-Ramirez, Jose L.; Schwarz, Julie K. [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Grigsby, Perry W., E-mail: pgrigsby@wustl.edu [Department of Radiation Oncology, Washington University School of Medicine, St Louis, Missouri (United States); Division of Nuclear Medicine, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Division of Gynecologic Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri (United States); Alvin J. Siteman Cancer Center, Washington University School of Medicine, St Louis, Missouri (United States)

    2014-11-15

    Purpose: Magnetic resonance imaging/diffusion weighted-imaging (MRI/DWI)-guided high-dose-rate (HDR) brachytherapy and {sup 18}F-fluorodeoxyglucose (FDG) — positron emission tomography/computed tomography (PET/CT)-guided intensity modulated radiation therapy (IMRT) for the definitive treatment of cervical cancer is a novel treatment technique. The purpose of this study was to report our analysis of dose-volume parameters predicting gross tumor volume (GTV) control. Methods and Materials: We analyzed the records of 134 patients with International Federation of Gynecology and Obstetrics stages IB1-IVB cervical cancer treated with combined MRI-guided HDR and IMRT from July 2009 to July 2011. IMRT was targeted to the metabolic tumor volume and lymph nodes by use of FDG-PET/CT simulation. The GTV for each HDR fraction was delineated by use of T2-weighted or apparent diffusion coefficient maps from diffusion-weighted sequences. The D100, D90, and Dmean delivered to the GTV from HDR and IMRT were summed to EQD2. Results: One hundred twenty-five patients received all irradiation treatment as planned, and 9 did not complete treatment. All 134 patients are included in this analysis. Treatment failure in the cervix occurred in 24 patients (18.0%). Patients with cervix failures had a lower D100, D90, and Dmean than those who did not experience failure in the cervix. The respective doses to the GTV were 41, 58, and 136 Gy for failures compared with 67, 99, and 236 Gy for those who did not experience failure (P<.001). Probit analysis estimated the minimum D100, D90, and Dmean doses required for ≥90% local control to be 69, 98, and 260 Gy (P<.001). Conclusions: Total dose delivered to the GTV from combined MRI-guided HDR and PET/CT-guided IMRT is highly correlated with local tumor control. The findings can be directly applied in the clinic for dose adaptation to maximize local control.

  8. Can pre- and postoperative magnetic resonance imaging predict recurrence-free survival after whole-gland high-intensity focused ablation for prostate cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Rosset, Remy; Bratan, Flavie [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Crouzet, Sebastien [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Universite de Lyon, Lyon (France); Faculte de Medecine Lyon Est, Universite Lyon 1, Lyon (France); Inserm, U1032, LabTau, Lyon (France); Tonoli-Catez, Helene [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Mege-Lechevallier, Florence [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Pathology, Lyon (France); Gelet, Albert [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urology, Lyon (France); Inserm, U1032, LabTau, Lyon (France); Rouviere, Olivier [Hopital Edouard Herriot, Hospices Civils de Lyon, Department of Urinary and Vascular Radiology, Lyon (France); Universite de Lyon, Lyon (France); Faculte de Medecine Lyon Est, Universite Lyon 1, Lyon (France); Inserm, U1032, LabTau, Lyon (France)

    2017-04-15

    Our aim was to assess whether magnetic resonance imaging (MRI) features predict recurrence-free survival (RFS) after prostate cancer high-intensity focused ultrasound (HIFU) ablation. We retrospectively selected 81 patients who underwent (i) whole-gland HIFU ablation between 2007 and 2011 as first-line therapy or salvage treatment after radiotherapy or brachytherapy, and (ii) pre- and postoperative MRI. On preoperative imaging, two senior (R1, R2) and one junior (R3) readers assessed the number of sectors invaded by the lesion with the highest Likert score (dominant lesion) using a 27-sector diagram. On postoperative imaging, readers assessed destruction of the dominant lesion using a three-level score. Multivariate analysis included the number of sectors invaded by the dominant lesion, its Likert and destruction scores, the pre-HIFU prostate-specific antigen (PSA) level, Gleason score, and the clinical setting (primary/salvage). The most significant predictor was the number of prostate sectors invaded by the dominant lesion for R2 and R3 (p≤0.001) and the destruction score of the dominant lesion for R1 (p = 0.011). The pre-HIFU PSA level was an independent predictor for R2 (p = 0.014), but with only marginal significance for R1 (p = 0.059) and R3 (p = 0.053). The dominant lesion's size and destruction assessed by MRI provide independent prognostic information compared with usual predictors. (orig.)

  9. Indocyanine green-loaded polydopamine-iron ions coordination nanoparticles for photoacoustic/magnetic resonance dual-modal imaging-guided cancer photothermal therapy.

    Science.gov (United States)

    Hu, Dehong; Liu, Chengbo; Song, Liang; Cui, Haodong; Gao, Guanhui; Liu, Peng; Sheng, Zonghai; Cai, Lintao

    2016-10-21

    Multi-modal imaging-guided cancer photothermal therapy (PTT) with advanced theranostic nanoagents can efficiently improve therapeutic efficacy and reduce treatment side effects. Herein, we have developed a theranostic nanoagent based on indocyanine green (ICG)-loaded polydopamine (PDA)-iron ions coordination nanoparticles (PDA-Fe(3+)-ICG NPs), which are used for photoacoustic (PA) and magnetic resonance (MR) dual-modal imaging-guided cancer PTT treatments. In this nanoplatform, ICG molecules, the U.S. Food and Drug Administration approved near-infrared (NIR) dye, absorbing on PDA NPs (a melanin-like biopolymer) to significantly increase the NIR optical absorption of PDA NPs nearly 6 times and decreases their fluorescence emission, which can improve the PA contrast ability and promote the photothermal conversion efficiency of PDA NPs. Meanwhile, Fe(3+) ions chelated on the PDA NPs act as a T1-weighted MRI contrast agent (r1 = 14 mM(-1) s(-1)). In a mouse 4T1 breast tumor model, PA/MRI dual-modal imaging and highly efficient PTT treatments with low laser density were achieved with remarkable therapeutic efficiency and minimal side effects. This study illustrates that the highly integrated and biocompatible PDA-based NPs can serve as a versatile nanoplatform by loading different imaging molecules and drugs for multi-modal imaging and cancer combination therapy.

  10. Magnetic resonance imaging-guided biopsies may improve diagnosis in biopsy-naive men with suspicion of prostate cancer

    DEFF Research Database (Denmark)

    Winther, Mads Dochedahl; Balslev, Ingegerd; Boesen, Lars

    2017-01-01

    INTRODUCTION: The purpose of this pilot study was to investigate whether a short prostate biparametric magnetic resonance imaging (bp-MRI) protocol provides a valuable diagnostic addition for biopsy guidance in biopsy-naive men with a suspicion of prostate cancer (PCa). METHODS: A total of 62......-bx seems feasible in biopsy-naive patients and may improve the detection of aggressive PCa in first-round biopsies. This pilot study thus provides an incentive for a larger investigation. FUNDING: Costs were covered by the Department of Radiology, Herlev Hospital, Denmark. TRIAL REGISTRATION: This study...

  11. Transcranial MRI-guided high-intensity focused ultrasound for treatment of essential tremor: A pilot study on the correlation between lesion size, lesion location, thermal dose, and clinical outcome.

    Science.gov (United States)

    Federau, Christian; Goubran, Maged; Rosenberg, Jarrett; Henderson, Jaimie; Halpern, Casey H; Santini, Veronica; Wintermark, Max; Butts Pauly, Kim; Ghanouni, Pejman

    2017-10-27

    Transcranial MR-guided high-intensity focused ultrasound (tcMRgFUS) is a promising noninvasive method to treat medication-refractory essential tremor. To define the correlation between lesion size after ablation, thermal dose, and clinical outcome in tcMRgFUS treatment of essential tremor. Retrospective. Eight patients with medication-refractory essential tremor were treated using a tcMRgFUS system at 3T. T 2 -weighted images were acquired immediately and at 1 year posttreatment at 3T. An atlas of the thalamic nuclei and dose maps were warped to the posttreatment images. The thermal dose, the immediate posttreatment lesion volume and 1-year final lesion volume, and the volumes confined inside the ventral division of the ventral lateral posterior thalamic nucleus (VLpv) were correlated to clinical outcome at 1 month and 1 year using Pearson's coefficient. The spatial region of treatment correlating with maximal clinical outcome was derived in a normalized space from average maps of clinical tremor score improvement at 1 year. Statistical significance was assessed using the Wilcoxon two-tailed rank test. The correlations between thermal dose, lesion volume posttreatment and at 1 year, and outcome at 1 year were good (r = 0.73, 0.65, 0.73, respectively), and were slightly better than at 1 month (r = 0.57, 0.49, 0.65). Reducing the measurement to include only the portion within the VLpv did not significantly modify the correlations (P = 0.09). The center of the spatial region of treatment was found in the anterior commissure - posterior commissure plane, 14.3 mm lateral from the midline, and 8.3 mm rostral to the posterior commissure. In this pilot study a good correlation was found between the size of the lesion, the thermal dose, and the clinical outcome in patients treated for essential tremor with ablation of the VLpv with tcMRgFUS. 1 Technical Efficacy: Stage 4 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in

  12. Fast lesion mapping during HIFU treatment using harmonic motion imaging guided focused ultrasound (HMIgFUS) in vitro and in vivo

    Science.gov (United States)

    Han, Yang; Wang, Shutao; Payen, Thomas; Konofagou, Elisa

    2017-04-01

    The successful clinical application of high intensity focused ultrasound (HIFU) ablation depends on reliable monitoring of the lesion formation. Harmonic motion imaging guided focused ultrasound (HMIgFUS) is an ultrasound-based elasticity imaging technique, which monitors HIFU ablation based on the stiffness change of the tissue instead of the echo intensity change in conventional B-mode monitoring, rendering it potentially more sensitive to lesion development. Our group has shown that predicting the lesion location based on the radiation force-excited region is feasible during HMIgFUS. In this study, the feasibility of a fast lesion mapping method is explored to directly monitor the lesion map during HIFU. The harmonic motion imaging (HMI) lesion map was generated by subtracting the reference HMI image from the present HMI peak-to-peak displacement map, as streamed on the computer display. The dimensions of the HMIgFUS lesions were compared against gross pathology. Excellent agreement was found between the lesion depth (r 2  =  0.81, slope  =  0.90), width (r 2  =  0.85, slope  =  1.12) and area (r 2  =  0.58, slope  =  0.75). In vivo feasibility was assessed in a mouse with a pancreatic tumor. These findings demonstrate that HMIgFUS can successfully map thermal lesions and monitor lesion development in real time in vitro and in vivo. The HMIgFUS technique may therefore constitute a novel clinical tool for HIFU treatment monitoring.

  13. Fast lesion mapping during HIFU treatment using harmonic motion imaging guided focused ultrasound (HMIgFUS) in vitro and in vivo.

    Science.gov (United States)

    Han, Yang; Wang, Shutao; Payen, Thomas; Konofagou, Elisa

    2017-04-21

    The successful clinical application of high intensity focused ultrasound (HIFU) ablation depends on reliable monitoring of the lesion formation. Harmonic motion imaging guided focused ultrasound (HMIgFUS) is an ultrasound-based elasticity imaging technique, which monitors HIFU ablation based on the stiffness change of the tissue instead of the echo intensity change in conventional B-mode monitoring, rendering it potentially more sensitive to lesion development. Our group has shown that predicting the lesion location based on the radiation force-excited region is feasible during HMIgFUS. In this study, the feasibility of a fast lesion mapping method is explored to directly monitor the lesion map during HIFU. The harmonic motion imaging (HMI) lesion map was generated by subtracting the reference HMI image from the present HMI peak-to-peak displacement map, as streamed on the computer display. The dimensions of the HMIgFUS lesions were compared against gross pathology. Excellent agreement was found between the lesion depth (r 2   =  0.81, slope  =  0.90), width (r 2   =  0.85, slope  =  1.12) and area (r 2   =  0.58, slope  =  0.75). In vivo feasibility was assessed in a mouse with a pancreatic tumor. These findings demonstrate that HMIgFUS can successfully map thermal lesions and monitor lesion development in real time in vitro and in vivo. The HMIgFUS technique may therefore constitute a novel clinical tool for HIFU treatment monitoring.

  14. The Effect of Rubric-Guided, Focused, Personalized Coaching Sessions and Video-Recorded Presentations on Teaching Skills Among Fourth-Year Medical Students: A Pilot Study.

    Science.gov (United States)

    Tchekmedyian, Vatche; Shields, Helen M; Pelletier, Stephen R; Pazo, Valeria C

    2017-11-01

    As medical students become residents, teaching becomes an expected and integral responsibility. Yet, training-for-teaching opportunities are lacking. In 2014, the authors designed a pilot study using rubric-guided, focused, personalized coaching sessions and video-recorded presentations to improve student teaching skills among fourth-year students at Harvard Medical School. In 2014-2015, the authors recruited students from an elective on how to tutor preclinical students for the pilot, which consisted of four phases: a precoaching teaching presentation, a 30- to 45-minute coaching session, a postcoaching teaching presentation, and blinded reviewer ratings. Students' pre- and postcoaching presentations were video recorded. Using a scoring rubric for 15 teaching skills, students rated their pre- and postcoaching videos. Blinded reviewers also rated the pre- and postcoaching presentations using the same rubric with an additional category to gauge their overall impression. Fourteen students completed all four phases of the pilot. Students' ratings demonstrated statistically significant improvement in several teaching skills, including presentation content (P rubric, using coaching in different teaching settings, addressing the interventions' generalizability, training coaches, and performing additional evaluations.

  15. Noninvasive localized delivery of Herceptin to the mouse brain by MRI-guided focused ultrasound-induced blood-brain barrier disruption

    Science.gov (United States)

    Kinoshita, Manabu; McDannold, Nathan; Jolesz, Ferenc A.; Hynynen, Kullervo

    2006-08-01

    Antibody-based anticancer agents are promising chemotherapeutic agents. Among these agents, Herceptin (trastuzumab), a humanized anti-human epidermal growth factor receptor 2 (HER2/c-erbB2) monoclonal antibody, has been used successfully in patients with breast cancer. However, in patients with brain metastasis, the blood-brain barrier limits its use, and a different delivery method is needed to treat these patients. Here, we report that Herceptin can be delivered locally and noninvasively into the mouse central nervous system through the blood-brain barrier under image guidance by using an MRI-guided focused ultrasound blood-brain barrier disruption technique. The amount of Herceptin delivered to the target tissue was correlated with the extent of the MRI-monitored barrier opening, making it possible to estimate indirectly the amount of Herceptin delivered. Histological changes attributable to this procedure were minimal. This method may represent a powerful technique for the delivery of macromolecular agents such as antibodies to treat patients with diseases of the central nervous system. brain tumor | microbubble

  16. Ultrasound-Guided Transesophageal High-Intensity Focused Ultrasound Cardiac Ablation in a Beating Heart: A Pilot Feasibility Study in Pigs.

    Science.gov (United States)

    Bessiere, Francis; N'djin, W Apoutou; Colas, Elodie Constanciel; Chavrier, Françoise; Greillier, Paul; Chapelon, Jean Yves; Chevalier, Philippe; Lafon, Cyril

    2016-08-01

    Catheter ablation for the treatment of arrhythmia is associated with significant complications and often-repeated procedures. Consequently, a less invasive and more efficient technique is required. Because high-intensity focused ultrasound (HIFU) enables the generation of precise thermal ablations in deep-seated tissues without harming the tissues in the propagation path, it has the potential to be used as a new ablation technique. A system capable of delivering HIFU into the heart by a transesophageal route using ultrasound (US) imaging guidance was developed and tested in vivo in six male pigs. HIFU exposures were performed on atria and ventricles. At the time of autopsy, visual inspection identified thermal lesions in the targeted areas in three of the animals. These lesions were confirmed by histologic analysis (mean size: 5.5 mm(2) × 11 mm(2)). No esophageal thermal injury was observed. One animal presented with bradycardia due to an atrio-ventricular block, which provides real-time confirmation of an interaction between HIFU and the electrical circuits of the heart. Thus, US-guided HIFU has the potential to minimally invasively create myocardial lesions without an intra-cardiac device. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  17. Targeted delivery of neural stem cells to the brain using MRI-guided focused ultrasound to disrupt the blood-brain barrier.

    Directory of Open Access Journals (Sweden)

    Alison Burgess

    Full Text Available Stem cell therapy is a promising strategy to treat neurodegenerative diseases, traumatic brain injury, and stroke. For stem cells to progress towards clinical use, the risks associated with invasive intracranial surgery used to deliver the cells to the brain, needs to be reduced. Here, we show that MRI-guided focused ultrasound (MRIgFUS is a novel method for non-invasive delivery of stem cells from the blood to the brain by opening the blood brain barrier (BBB in specific brain regions. We used MRI guidance to target the ultrasound beam thereby delivering the iron-labeled, green fluorescent protein (GFP-expressing neural stem cells specifically to the striatum and the hippocampus of the rat brain. Detection of cellular iron using MRI established that the cells crossed the BBB to enter the brain. After sacrifice, 24 hours later, immunohistochemical analysis confirmed the presence of GFP-positive cells in the targeted brain regions. We determined that the neural stem cells expressed common stem cell markers (nestin and polysialic acid suggesting they survived after transplantation with MRIgFUS. Furthermore, delivered stem cells expressed doublecortin in vivo indicating the stem cells were capable of differentiating into neurons. Together, we demonstrate that transient opening of the BBB with MRIgFUS is sufficient for transplantation of stem cells from the blood to targeted brain structures. These results suggest that MRIgFUS may be an effective alternative to invasive intracranial surgery for stem cell transplantation.

  18. Case-control study of low-back pain referred for magnetic resonance imaging, with special focus on whole-body vibration.

    Science.gov (United States)

    Palmer, Keith T; Harris, Clare E; Harris, E Claire; Griffin, Michael J; Bennett, James; Reading, Isabel; Sampson, Madelaine; Coggon, David

    2008-10-01

    This study investigated risk factors for low-back pain among patients referred for magnetic resonance imaging (MRI), with special focus on whole-body vibration. A case-control approach was used. The study population comprised working-aged persons from a catchment area for radiology services. The cases were those in a consecutive series referred for a lumbar MRI because of low-back pain. The controls were age- and gender-matched persons X-rayed for other reasons. Altogether, 252 cases and 820 controls were studied, including 185 professional drivers. The participants were questioned about physical factors loading the spine, psychosocial factors, driving, personal characteristics, mental health, and certain beliefs about low-back pain. Exposure to whole-body vibration was assessed by six measures, including weekly duration of professional driving, hours driven in one period, and current root mean square A(8). Associations with whole-body vibration were examined with adjustment for age, gender, and other potential confounders. Strong associations were found with poor mental health and belief in work as a causal factor for low-back pain, and with occupational sitting for > or =3 hours while not driving. Associations were also found for taller stature, consulting propensity, body mass index, smoking history, fear-avoidance beliefs, frequent twisting, low decision latitude, and low support at work. However, the associations with the six metrics of whole-body vibration were weak and not statistically significant, and no exposure-response relationships were found. Little evidence of a risk from professional driving or whole-body vibration was found. Drivers were substantially less heavily exposed to whole-body vibration than in some earlier surveys. Nonetheless, it seems that, at the population level, whole-body vibration is not an important cause of low-back pain among those referred for MRI.

  19. Moderate-to-deep sedation technique, using propofol and ketamine, allowing synchronised breathing for magnetic resonance high-intensity focused ultrasound (MR-HIFU) treatment for uterine fibroids : a pilot study

    NARCIS (Netherlands)

    Vaessen, Hermanus H B; Knuttel, F M; van Breugel, J M M|info:eu-repo/dai/nl/413639975; Ikink, M E; Dieleman, J M|info:eu-repo/dai/nl/304817902; van den Bosch, Maurice|info:eu-repo/dai/nl/182981630; Knape, J T A|info:eu-repo/dai/nl/071757481

    2017-01-01

    BACKGROUND: Magnetic resonance high-intensity focused ultrasound (MR-HIFU) treatment for uterine fibroids is rapidly gaining popularity as a treatment modality. This procedure is generally uncomfortable, painful, and requires minimal or absence of movement and an MR-HIFU synchronised breathing

  20. Cone beam computed tomography guided treatment delivery and planning verification for magnetic resonance imaging only radiotherapy of the brain

    DEFF Research Database (Denmark)

    Edmund, Jens M.; Andreasen, Daniel; Mahmood, Faisal

    2015-01-01

    Background. Radiotherapy based on MRI only (MRI-only RT) shows a promising potential for the brain. Much research focuses on creating a pseudo computed tomography (pCT) from MRI for treatment planning while little attention is often paid to the treatment delivery. Here, we investigate if cone beam...

  1. Prospective nonrandomized study of diagnostic accuracy comparing prostate cancer detection by transrectal ultrasound-guided biopsy to magnetic resonance imaging with subsequent MRI-guided biopsy in biopsy-naïve patients.

    Science.gov (United States)

    Castellucci, Roberto; Linares Quevedo, Ana I; Sánchez Gómez, Francisco J; Díez Rodríguez, Jesús; Cogorno, Leopoldo; Cogollos Acuña, Isidro; Salmerón Béliz, Isabel; Muñoz Fernández de Legaría, Marta; Martínez Piñeiro, Luis

    2017-12-01

    To evaluate the diagnostic efficacy in cancer prostate (PCa) of Multiparametric prostate magnetic resonance imaging (mp-MRI) targeted biopsy compared to standard systematic transrectal ultrasound-guided biopsy (TRUSGB) in biopsy-naïve patients. A total of 168 biopsy-naïve men with clinical suspicion of PCa due to elevated PSA levels and/or an abnormal digital rectal examination were consecutively enrolled from July 2011 to July 2014. All patients underwent TRUSGB. Patients with equivocal (Pi-rads 3) or suspicious lesion (Pi-rads 4-5), were additionally biopsied using two cores, by the same operator (cognitive technique). Among the 168 cases, mp-MRI was equivocal for PCa (Pi-rads 3) in 46 subjects (27.4%) and suspicious (Pi-rads 4, 5) in 40 cases (23.8%). Of the 69 patients with PCa, standard TRUSGB showed Gleason ≥7 in 75% of patients with Pirads 3 and 77.8% in cases with Pirads 4-5 on mp-MRI. Among the 40 patients with Pi-rads 4-5 lesion on the MRI, cognitive mp-MRI-guided biopsy (MRCGB) detected a higher number of cases of PCa with a Gleason score equal or superior to 7 (90%) with a higher negative predictive value (97.5%) than cases with Pi-rads 3 lesion or subjects with TRUSGB alone. mp-MRI followed by selective biopsy seems to be a valuable tool to improve the diagnosis of intermediate and high risk PCa compared to standard TRUSGB.

  2. Retrospective comparison of direct in-bore magnetic resonance imaging (MRI)-guided biopsy and fusion-guided biopsy in patients with MRI lesions which are likely or highly likely to be clinically significant prostate cancer.

    Science.gov (United States)

    Venderink, Wulphert; van der Leest, Marloes; van Luijtelaar, Annemarijke; van de Ven, Wendy J M; Fütterer, Jurgen J; Sedelaar, J P Michiel; Huisman, Henkjan J

    2017-12-01

    To compare clinically significant prostate cancer (csPCa) detection rates between magnetic resonance imaging (MRI)-transrectal ultrasound (TRUS) fusion-guided prostate biopsy (FGB) and direct in-bore MRI-guided biopsy (MRGB). We performed a comparison of csPCa detection rates between FGB and MRGB. Included patients had (1) at least one prior negative TRUS biopsy; (2) a Prostate Imaging Reporting and Data System (PI-RADS) 4 or 5 lesion and (3) a lesion size of ≥8 mm measured in at least one direction. We considered a Gleason score ≥7 being csPCa. Descriptive statistics with 95% confidence intervals (CI) were used to determine any differences. We included 51 patients with FGB (59 PI-RADS 4 and 41% PI-RADS 5) and 227 patients with MRGB (34 PI-RADS 4 and 66% PI-RADS 5). Included patients had a median age of 69 years (IQR, 65-72) and a median PSA level of 11.0 ng/ml (IQR, 7.4-15.1) and a median age of 67 years (IQR, 61-70), the median PSA 12.8 ng/ml (IQR, 9.1-19.0) within the FGB and the MRGB group, respectively. Detection rates of csPCA did not differ significantly between FGB and MRGB, 49 vs. 61%, respectively. We did not detect significant differences between FGB and MRGB in the detection of csPCa. The differences in detection ratios between both biopsy techniques are narrow with an increasing lesion size. This study warrants further studies to optimize selection of best biopsy modality.

  3. High-resolution numerical simulation of Left Ventricular Hemodynamics Guided by in-vivo Cardiac Magnetic Resonance Data

    Science.gov (United States)

    Le, Trung; Sotiropoulos, Fotis; Mirabella, Lucia; Chaffins, Brandon; Santhanakrishnan, Arvind; Oshinski, John; Yoganathan, Ajit; University of Minnesota Collaboration; Georgia Institute of Technology Collaboration

    2012-11-01

    We study the fluid dynamics within a patient-specific left ventricle (LV) during diastole using both numerical simulations and in-vivo data. The kinematics of the LV is reconstructed from high-resolution Magnetic Resonance Imaging (MRI) data acquired on a healthy volunteer, using image segmentation and a surface registration process. The flow velocity is acquired using phase-contrast MRI at the mitral orifice and at an additional parallel plane inside the ventricle. Numerical simulations are carried out using the CURVIB method (Ge et al., JCP, 2007) with the MRI reconstructed LV wall motion imposed as boundary condition. The numerical simulations show the highly dynamic environment of the flow field. The mitral vortex ring is formed during early diastolic filling and breaks down into small scale structures. The simulated hemodynamics are compared with phase-contrast MRI measurements and previous simulations in which the LV wall motion was obtained from a lumped parameter model (Le and Sotiropoulos, Eur. J. Mechanics B - Fluids, 2012). We acknowlege NIH Grant RO1-HL-07262 and the Minnesota Supercomputing Institute support.

  4. Magnetic resonance imaging properties of multimodality anthropomorphic silicone rubber phantoms for validating surgical robots and image guided therapy systems

    Science.gov (United States)

    Cheung, Carling L.; Looi, Thomas; Drake, James; Kim, Peter C. W.

    2012-02-01

    The development of image guided robotic and mechatronic platforms for medical applications requires a phantom model for initial testing. Finding an appropriate phantom becomes challenging when the targeted patient population is pediatrics, particularly infants, neonates or fetuses. Our group is currently developing a pediatricsized surgical robot that operates under fused MRI and laparoscopic video guidance. To support this work, we describe a method for designing and manufacturing silicone rubber organ phantoms for the purpose of testing the robotics and the image fusion system. A surface model of the organ is obtained and converted into a mold that is then rapid-prototyped using a 3D printer. The mold is filled with a solution containing a particular ratio of silicone rubber to slacker additive to achieve a specific set of tactile and imaging characteristics in the phantom. The expected MRI relaxation times of different ratios of silicone rubber to slacker additive are experimentally quantified so that the imaging properties of the phantom can be matched to those of the organ that it represents. Samples of silicone rubber and slacker additive mixed in ratios ranging from 1:0 to 1:1.5 were prepared and scanned using inversion recovery and spin echo sequences with varying TI and TE, respectively, in order to fit curves to calculate the expected T1 and T2 relaxation times of each ratio. A set of infantsized abdominal organs was prepared, which were successfully sutured by the robot and imaged using different modalities.

  5. Magnetic resonance imaging (MRI)-guided transurethral ultrasound therapy of the prostate: a preclinical study with radiological and pathological correlation using customised MRI-based moulds.

    Science.gov (United States)

    Partanen, Ari; Yerram, Nitin K; Trivedi, Hari; Dreher, Matthew R; Oila, Juha; Hoang, Anthony N; Volkin, Dmitry; Nix, Jeffrey; Turkbey, Baris; Bernardo, Marcelino; Haines, Diana C; Benjamin, Compton J; Linehan, W Marston; Choyke, Peter; Wood, Bradford J; Ehnholm, Gösta J; Venkatesan, Aradhana M; Pinto, Peter A

    2013-08-01

    To characterise the feasibility and safety of a novel transurethral ultrasound (US)-therapy device combined with real-time multi-plane magnetic resonance imaging (MRI)-based temperature monitoring and temperature feedback control, to enable spatiotemporally precise regional ablation of simulated prostate gland lesions in a preclinical canine model. To correlate ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. Three dogs were treated with three targeted ablations each, using a prototype MRI-guided transurethral US-therapy system (Philips Healthcare, Vantaa, Finland). MRI provided images for treatment planning, guidance, real-time multi-planar thermometry, as well as post-treatment evaluation of efficacy. After treatment, specimens underwent histopathological analysis to determine the extent of necrosis and cell viability. Statistical analyses (Pearson's correlation, Student's t-test) were used to evaluate the correlation between ablation volumes measured with intra-procedural cumulative thermal damage estimates, post-procedural MRI, and histopathology. MRI combined with a transurethral US-therapy device enabled multi-planar temperature monitoring at the target as well as in surrounding tissues, allowing for safe, targeted, and controlled ablations of prescribed lesions. Ablated volumes measured by cumulative thermal dose positively correlated with volumes determined by histopathological analysis (r(2) 0.83, P MRI showed a positive correlation with non-viable areas on histopathological analysis (r(2) 0.89, P MRI (r(2) 0.77, P 0.05, Student's t-test). MRI-guided transurethral US therapy enabled safe and targeted ablations of prescribed lesions in a preclinical canine prostate model. Ablation volumes were reliably predicted by intra- and post-procedural imaging. Clinical studies are needed to confirm the feasibility, safety, oncological control, and functional outcomes of this therapy in

  6. Magnetic resonance-guided laser-induced thermotherapy in patients with oligonodular hepatocellular carcinoma: long-term results over a 15-year period.

    Science.gov (United States)

    Eichler, Katrin; Zangos, Stephan; Gruber-Rouh, Tatjana; Vogl, Thomas J; Mack, Martin G

    2012-10-01

    To prospectively evaluate the therapeutic potential of magnetic resonance (MR)-guided laser-induced thermotherapy (LITT) in patients with oligonodular hepatocellular carcinoma. A total of 113 patients with 175 intrahepatic lesions were treated with MR-guided LITT. The Nd-YAG laser fiber was introduced with a percutaneously positioned irrigated laser application system. Qualitative and quantitative MR parameters and clinical data were evaluated. Survival data were calculated using the Kaplan-Meier method. All patients tolerated the procedure well under local anesthesia. The total procedure time was 90 minutes. All observed complications were minor and no further treatment was necessary. Online MR thermometry allowed exact visualization of the extension of laser-induced changes and their relationship to the neighboring anatomy. Lesions up to 2 cm in diameter could be efficiently treated with a single laser application; larger lesions were treated with a dual, triple, and quadruple simultaneous application. In 98% of the patients we achieved a complete necrosis of the tumor and up to 5 mm of safety margin. The mean survival rate for all patients, with calculation started on the date of diagnosis of the HCC nodules treated with LITT, was 4.9 years (95% confidence interval, 3.6, 5.1). The median survival rate for all patients, with calculation started on the date of diagnosis of the HCC nodules treated with LITT, was 3.5 years (95% confidence interval, 2.7, 4.2). One-year survival was 95%; 2-year survival 72%, 3-year survival 54%; and 5-year survival 30%. In intrahepatic oligonodular involvement of hepatocellular carcinoma LITT appears to be an effective therapeutic procedure.

  7. HematoPorphyrin Monomethyl Ether polymer contrast agent for ultrasound/photoacoustic dual-modality imaging-guided synergistic high intensity focused ultrasound (HIFU) therapy

    Science.gov (United States)

    Yan, Sijing; Lu, Min; Ding, Xiaoya; Chen, Fei; He, Xuemei; Xu, Chunyan; Zhou, Hang; Wang, Qi; Hao, Lan; Zou, Jianzhong

    2016-08-01

    This study is to prepare a hematoporphyrin monomethyl ether (HMME)-loaded poly(lactic-co-glycolic acid) (PLGA) microcapsules (HMME/PLGA), which could not only function as efficient contrast agent for ultrasound (US)/photoacoustic (PA) imaging, but also as a synergistic agent for high intensity focused ultrasound (HIFU) ablation. Sonosensitizer HMME nanoparticles were integrated into PLGA microcapsules with the double emulsion evaporation method. After characterization, the cell-killing and cell proliferation-inhibiting effects of HMME/PLGA microcapsules on ovarian cancer SKOV3 cells were assessed. The US/PA imaging-enhancing effects and synergistic effects on HIFU were evaluated both in vitro and in vivo. HMME/PLGA microcapsules were highly dispersed with well-defined spherical morphology (357 ± 0.72 nm in diameter, PDI = 0.932). Encapsulation efficiency and drug-loading efficiency were 58.33 ± 0.95% and 4.73 ± 0.15%, respectively. The HMME/PLGA microcapsules remarkably killed the SKOV3 cells and inhibited the cell proliferation, significantly enhanced the US/PA imaging results and greatly enhanced the HIFU ablation effects on ovarian cancer in nude mice by the HMME-mediated sono-dynamic chemistry therapy (SDT). HMME/PLGA microcapsules represent a potential multifunctional contrast agent for HIFU diagnosis and treatment, which might provide a novel strategy for the highly efficient imaging-guided non-invasive HIFU synergistic therapy for cancers by SDT in clinic.

  8. Feasibility Study on MR-Guided High-Intensity Focused Ultrasound Ablation of Sciatic Nerve in a Swine Model: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Kaye, Elena A., E-mail: kayee@mskcc.org [Memorial Sloan Kettering Cancer Center, Department of Medical Physics (United States); Gutta, Narendra Babu, E-mail: gnbabu.aiims@gmail.com [Memorial Sloan Kettering Cancer Center, Department of Radiology (United States); Monette, Sebastien, E-mail: monettes@mskcc.org [The Rockefeller University, Tri-Institutional Laboratory of Comparative Pathology, Memorial Sloan Kettering Cancer Center, Weill Cornell Medical College (United States); Gulati, Amitabh, E-mail: gulatia@mskcc.org; Loh, Jeffrey, E-mail: jeffreyloh@gmail.com [Memorial Sloan Kettering Cancer Center, Department of Anesthesiology-Critical Care (United States); Srimathveeravalli, Govindarajan, E-mail: srimaths@mskcc.org [Memorial Sloan Kettering Cancer Center, Department of Radiology (United States); Ezell, Paula C., E-mail: paula.ezell@intusurg.com [The Rockefeller University, Tri-Institutional Laboratory of Comparative Pathology, Memorial Sloan Kettering Cancer Center, Weill Cornell Medical College (United States); Erinjeri, Joseph P., E-mail: erinjerj@mskcc.org; Solomon, Stephen B., E-mail: solomons@mskcc.org; Maybody, Majid, E-mail: maybodym@mskcc.org [Memorial Sloan Kettering Cancer Center, Department of Radiology (United States)

    2015-08-15

    IntroductionSpastic patients often seek neurolysis, the permanent destruction of the sciatic nerve, for better pain management. MRI-guided high-intensity focused ultrasound (MRgHIFU) may serve as a noninvasive alternative to the prevailing, more intrusive techniques. This in vivo acute study is aimed at performing sciatic nerve neurolysis using a clinical MRgHIFU system.MethodsThe HIFU ablation of sciatic nerves was performed in swine (n = 5) using a HIFU system integrated with a 3 T MRI scanner. Acute lesions were confirmed using T1-weighted contrast-enhanced (CE) MRI and histopathology using hematoxylin and eosin staining. The animals were euthanized immediately following post-ablation imaging.ResultsReddening and mild thickening of the nerve and pallor of the adjacent muscle were seen in all animals. The HIFU-treated sections of the nerves displayed nuclear pyknosis of Schwann cells, vascular hyperemia, perineural edema, hyalinization of the collagenous stroma of the nerve, myelin sheet swelling, and loss of axons. Ablations were visible on CE MRI. Non-perfused volume of the lesions (5.8–64.6 cc) linearly correlated with estimated lethal thermal dose volume (4.7–34.2 cc). Skin burn adjacent to the largest ablated zone was observed in the first animal. Bilateral treatment time ranged from 55 to 138 min, and preparation time required 2 h on average.ConclusionThe acute pilot study in swine demonstrated the feasibility of a noninvasive neurolysis of the sciatic nerve using a clinical MRgHIFU system. Results revealed that acute HIFU nerve lesions were detectable on CE MRI, gross pathology, and histology.

  9. Accuracy of Palpation-Guided Catheter Placement for Muscle Pressure Measurements in Suspected Deep Posterior Chronic Exertional Compartment Syndrome of the Lower Leg: A Magnetic Resonance Imaging Study.

    Science.gov (United States)

    Winkes, Michiel B; Tseng, Carroll M; Pasmans, Huub L; van der Cruijsen-Raaijmakers, Marike; Hoogeveen, Adwin R; Scheltinga, Marc R

    2016-10-01

    A diagnosis of lower leg deep posterior chronic exertional compartment syndrome (dp-CECS) is made by a dynamic pressure measurement. The insertion of a pressure catheter is guided by anatomic landmarks (freehand) or by ultrasound. The catheter tip is ideally positioned in the tibialis posterior muscle (TP). The accuracy of in vivo catheter placement using lower leg magnetic resonance imaging (MRI) in healthy patients suspected of having dp-CECS has never been studied. To analyze whether a freehand catheter insertion results in accurate positioning in the TP as confirmed by MRI in patients with suspected dp-CECS. Case series; Level of evidence, 4. Catheters were inserted into central portions of the TP using a standard puncturing technique guided by lower leg anatomic landmarks. After timed muscle pressure measurements during a standard provocative treadmill running test, lower leg MRI scans were obtained and evaluated by 2 skilled radiologists. Catheter tip placement was termed accurate (in the TP), suboptimal (in the deep posterior compartment but outside the TP), or inaccurate (outside the deep posterior compartment). Between March 2013 and September 2014, a total of 24 patients (8 male, 16 female; mean age, 30 years [range, 18-54 years]) underwent an intracompartmental pressure (ICP) measurement, followed by MRI. Cardinal symptoms were pain during exertion (20% very severe, 53% severe, and 20% moderate) and tightness (29% very severe, 43% severe). Symptoms were bilateral in 74% of patients. Nine of the 24 patients were diagnosed with dp-CECS based on elevated ICPs. Of the 24 patients, catheter tip placement was accurate in 10 (42%), whereas suboptimal placement was achieved in 9 (38%). Five procedures were inaccurate (transition zone between the deep and superficial compartments, n = 3; in the superficial lower leg compartment, n = 2). Signs of a hematoma were found in 38% of the patients, although there were no associated clinical symptoms. Palpation-guided

  10. Magnetic Resonance Imaging (MRI) Markers for MRI-Guided High-Dose-Rate Brachytherapy: Novel Marker-Flange for Cervical Cancer and Marker Catheters for Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Schindel, Joshua; Muruganandham, Manickam [Department of Radiation Oncology, University of Iowa, Iowa City, Iowa (United States); Pigge, F. Christopher [Department of Chemistry, University of Iowa, Iowa City, Iowa (United States); Anderson, James [Department of Radiation Oncology, University of Iowa, Iowa City, Iowa (United States); Kim, Yusung, E-mail: yusung-kim@uiowa.edu [Department of Radiation Oncology, University of Iowa, Iowa City, Iowa (United States)

    2013-06-01

    Purpose: To present a novel marker-flange, addressing source-reconstruction uncertainties due to the artifacts of a titanium intracavitary applicator used for magnetic resonance imaging (MRI)-guided high-dose-rate (HDR) brachytherapy (BT); and to evaluate 7 different MRI marker agents used for interstitial prostate BT and intracavitary gynecologic HDR BT when treatment plans are guided by MRI. Methods and Materials: Seven MRI marker agents were analyzed: saline solution, Conray-60, copper sulfate (CuSO{sub 4}) (1.5 g/L), liquid vitamin E, fish oil, 1% agarose gel (1 g agarose powder per 100 mL distilled water), and a cobalt–chloride complex contrast (C4) (CoCl{sub 2}/glycine = 4:1). A plastic, ring-shaped marker-flange was designed and tested on both titanium and plastic applicators. Three separate phantoms were designed to test the marker-flange, interstitial catheters for prostate BT, and intracavitary catheters for gynecologic HDR BT. T1- and T2-weighted MRI were analyzed for all markers in each phantom and quantified as percentages compared with a 3% agarose gel background. The geometric accuracy of the MR signal for the marker-flange was measured using an MRI-CT fusion. Results: The CuSO{sub 4} and C4 markers on T1-weighted MRI and saline on T2-weighted MRI showed the highest signals. The marker-flange showed hyper-signals of >500% with CuSO{sub 4} and C4 on T1-weighted MRI and of >400% with saline on T2-weighted MRI on titanium applicators. On T1-weighted MRI, the MRI signal inaccuracies of marker-flanges were measured <2 mm, regardless of marker agents, and that of CuSO{sub 4} was 0.42 ± 0.14 mm. Conclusion: The use of interstitial/intracavitary markers for MRI-guided prostate/gynecologic BT was observed to be feasible, providing accurate source pathway reconstruction. The novel marker-flange can produce extremely intense, accurate signals, demonstrating its feasibility for gynecologic HDR BT.

  11. Magnetic-resonance imaging for kinetic analysis of permeability changes during focused ultrasound-induced blood-brain barrier opening and brain drug delivery.

    Science.gov (United States)

    Chai, Wen-Yen; Chu, Po-Chun; Tsai, Meng-Yen; Lin, Yu-Chun; Wang, Jiun-Jie; Wei, Kuo-Chen; Wai, Yau-Yau; Liu, Hao-Li

    2014-10-28

    Focused ultrasound (FUS) with the presence of microbubbles has been shown to induce transient and local opening of the blood-brain barrier (BBB) for the delivery of therapeutic molecules which normally cannot penetrate into the brain. The success of FUS brain-drug delivery relies on its integration with in-vivo imaging to monitor kinetic change of therapeutic molecules into the brain. In this study, we developed a dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) technique for kinetic analysis of delivered molecules during FUS-BBB opening. Three kinetic parameters (Ktrans, Ve, Kep) were characterized dynamically to describe BBB-permeability at two FUS exposure conditions (0.4 or 0.8MPa) over 24h. Ktrans, defined as the influx volume transfer constant from plasma to EES, and Ve, the EES volume fraction, were both found to be pressure-dependent. Ktrans and Ve showed a peak increase of 0.0086-0.0131min(-1) (for 0.4-0.8MPa pressure), and 0.0431-0.0692, respectively, immediately after FUS exposure. Both parameters subsequently decreased exponentially as a function of time, with estimated half-lives of decay of 2.89-5.3 and 2.2-4.93h, respectively. The kinetics of Kep, defined as the efflux rate constant from the extracellular extravascular space (EES) to the plasma, were complementary to Ktrans, with an initial decrease from 0.2010 to 0.1901min(-1) followed by a significantly longer recovery time (half-life of 17.39-99.92h). Our observations strongly supported the existence of imbalanced and mismatched kinetics of influx (Ktrans) and efflux (Kep) between the plasma and EES, indicating the existence of directional permeability during FUS-BBB opening. We further showed that kinetic change determined by DCE-MRI correlated well with the concentration of Evans Blue (EB)-albumin (coefficient of 0.74-0.89). These findings suggest that MRI kinetic monitoring may serve as an alternative method for in-vivo monitoring of pharmacokinetics and pharmacodynamics (PK

  12. In Vivo Dual-Modality Fluorescence and Magnetic Resonance Imaging-Guided Lymph Node Mapping with Good Biocompatibility Manganese Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Yonghua Zhan

    2017-12-01

    Full Text Available Multifunctional manganese oxide nanoparticles (NPs with impressive enhanced T1 contrast ability show great promise in biomedical diagnosis. Herein, we developed a dual-modality imaging agent system based on polyethylene glycol (PEG-coated manganese oxide NPs conjugated with organic dye (Cy7.5, which functions as a fluorescence imaging (FI agent as well as a magnetic resonance imaging (MRI imaging agent. The formed Mn3O4@PEG-Cy7.5 NPs with the size of ~10 nm exhibit good colloidal stability in different physiological media. Serial FI and MRI studies that non-invasively assessed the bio-distribution pattern and the feasibility for in vivo dual-modality imaging-guided lymph node mapping have been investigated. In addition, histological and biochemical analyses exhibited low toxicity even at a dose of 20 mg/kg in vivo. Since Mn3O4@PEG-Cy7.5 NPs exhibited desirable properties as imaging agents and good biocompatibility, this work offers a robust, safe, and accurate diagnostic platform based on manganese oxide NPs for tumor metastasis diagnosis.

  13. In vitro study of novel gadolinium-loaded liposomes guided by GBI-10 aptamer for promising tumor targeting and tumor diagnosis by magnetic resonance imaging

    Science.gov (United States)

    Gu, Meng-Jie; Li, Kun-Feng; Zhang, Lan-Xin; Wang, Huan; Liu, Li-Si; Zheng, Zhuo-Zhao; Han, Nan-Yin; Yang, Zhen-Jun; Fan, Tian-Yuan

    2015-01-01

    Novel gadolinium-loaded liposomes guided by GBI-10 aptamer were developed and evaluated in vitro to enhance magnetic resonance imaging (MRI) diagnosis of tumor. Nontargeted gadolinium-loaded liposomes were achieved by incorporating amphipathic material, Gd (III) [N,N-bis-stearylamidomethyl-N′-amidomethyl] diethylenetriamine tetraacetic acid, into the liposome membrane using lipid film hydration method. GBI-10, as the targeting ligand, was then conjugated onto the liposome surface to get GBI-10-targeted gadolinium-loaded liposomes (GTLs). Both nontargeted gadolinium-loaded liposomes and GTLs displayed good dispersion stability, optimal size, and zeta potential for tumor targeting, as well as favorable imaging properties with enhanced relaxivity compared with a commercial MRI contrast agent (CA), gadopentetate dimeglumine. The use of GBI-10 aptamer in this liposomal system was intended to result in increased accumulation of gadolinium at the periphery of C6 glioma cells, where the targeting extracellular matrix protein tenascin-C is overexpressed. Increased cellular binding of GTLs to C6 cells was confirmed by confocal microscopy, flow cytometry, and MRI, demonstrating the promise of this novel delivery system as a carrier of MRI contrast agent for the diagnosis of tumor. These studies provide a new strategy furthering the development of nanomedicine for both diagnosis and therapy of tumor. PMID:26316749

  14. Wayside Bearing Fault Diagnosis Based on Envelope Analysis Paved with Time-Domain Interpolation Resampling and Weighted-Correlation-Coefficient-Guided Stochastic Resonance

    Directory of Open Access Journals (Sweden)

    Yongbin Liu

    2017-01-01

    Full Text Available Envelope spectrum analysis is a simple, effective, and classic method for bearing fault identification. However, in the wayside acoustic health monitoring system, owing to the high relative moving speed between the railway vehicle and the wayside mounted microphone, the recorded signal is embedded with Doppler effect, which brings in shift and expansion of the bearing fault characteristic frequency (FCF. What is more, the background noise is relatively heavy, which makes it difficult to identify the FCF. To solve the two problems, this study introduces solutions for the wayside acoustic fault diagnosis of train bearing based on Doppler effect reduction using the improved time-domain interpolation resampling (TIR method and diagnosis-relevant information enhancement using Weighted-Correlation-Coefficient-Guided Stochastic Resonance (WCCSR method. First, the traditional TIR method is improved by incorporating the original method with kinematic parameter estimation based on time-frequency analysis and curve fitting. Based on the estimated parameters, the Doppler effect is removed using the TIR easily. Second, WCCSR is employed to enhance the diagnosis-relevant period signal component in the obtained Doppler-free signal. Finally, paved with the above two procedures, the local fault is identified using envelope spectrum analysis. Simulated and experimental cases have verified the effectiveness of the proposed method.

  15. Design, analysis and control of a novel tendon-driven magnetic resonance-guided robotic system for minimally invasive breast surgery.

    Science.gov (United States)

    Jiang, Shan; Lou, Jinlong; Yang, Zhiyong; Dai, Jiansheng; Yu, Yan

    2015-09-01

    Biopsy and brachytherapy for small core breast cancer are always difficult medical problems in the field of cancer treatment. This research mainly develops a magnetic resonance imaging-guided high-precision robotic system for breast puncture treatment. First, a 5-degree-of-freedom tendon-based surgical robotic system is introduced in detail. What follows are the kinematic analysis and dynamical modeling of the robotic system, where a mathematic dynamic model is established using the Lagrange method and a lumped parameter tendon model is used to identify the nonlinear gain of the tendon-sheath transmission system. Based on the dynamical models, an adaptive proportional-integral-derivative controller with friction compensation is proposed for accurate position control. Through simulations using different sinusoidal input signals, we observe that the sinusoidal tracking error at 1/2π Hz is 0.41 mm. Finally, the experiments on tendon-sheath transmission and needle insertion performance are conducted, which show that the insertion precision is 0.68 mm in laboratory environment. © IMechE 2015.

  16. Cost-Effectiveness of Mobile App-Guided Training in Extended Focused Assessment with Sonography for Trauma (eFAST): A Randomized Trial.

    Science.gov (United States)

    Nilsson, Philip Mørkeberg; Todsen, Tobias; Subhi, Yousif; Graumann, Ole; Nolsøe, Christian Pallson; Tolsgaard, Martin Grønnebæk

    2017-12-01

     Ultrasound training is associated with a long learning curve and use of substantial faculty resources. Self-directed ultrasound training may decrease the need for faculty-led teaching. Mobile apps seem promising for use in self-directed ultrasound training, but no studies have examined the cost-effectiveness of mobile app-guided training versus traditional formats such as textbook-guided training. This study evaluated the cost-effectiveness of mobile app-guided versus textbook-guided ultrasound training.  First-year residents (n = 38) with no previous ultrasound experience were randomized into mobile app-guided versus textbook-guided self-directed ultrasound training groups. Participants completed a transfer test involving four patient cases and a theoretical test on diagnostic accuracy. Two ultrasound experts assessed the residents' performance using the Objective Structured Assessment of Ultrasound Skills (OSAUS) scale. The costs of developing mobile app and textbook material were calculated and used for the analysis of cost-effectiveness.  34 participants completed the transfer test. There was no statistically significant difference in test performance or diagnostic accuracy between the mobile app-guided (mean-OSAUS 42.3 % [95 %CI38.5 - 46.0 %]) and textbook-guided groups (mean-OSAUS 45.3 % [95 %CI39.3 - 51.3 %]) (d.f. [1.33] = 0.45, p = 0.41). However, development costs differed greatly for each instructional format. Textbook-guided training was significantly more cost-effective than mobile app-guided training (Incremental Cost Effectiveness Ratio -861 967 [95 %CI-1071.7 to-3.2] USD/pct. point change in OSAUS score).  Mobile app-guided ultrasound training is less cost-effective than textbook-guided self-directed training. This study underlines the need for careful evaluation of cost-effectiveness when introducing technological innovations for clinical skills training. © Georg Thieme Verlag KG Stuttgart · New York.

  17. SU-E-J-03: Characterization of the Precision and Accuracy of a New, Preclinical, MRI-Guided Focused Ultrasound System for Image-Guided Interventions in Small-Bore, High-Field Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Ellens, N [Johns Hopkins University, Baltimore, Maryland (United States); Farahani, K [National Cancer Institute, Bethesda, MD (United States)

    2015-06-15

    Purpose: MRI-guided focused ultrasound (MRgFUS) has many potential and realized applications including controlled heating and localized drug delivery. The development of many of these applications requires extensive preclinical work, much of it in small animal models. The goal of this study is to characterize the spatial targeting accuracy and reproducibility of a preclinical high field MRgFUS system for thermal ablation and drug delivery applications. Methods: The RK300 (FUS Instruments, Toronto, Canada) is a motorized, 2-axis FUS positioning system suitable for small bore (72 mm), high-field MRI systems. The accuracy of the system was assessed in three ways. First, the precision of the system was assessed by sonicating regular grids of 5 mm squares on polystyrene plates and comparing the resulting focal dimples to the intended pattern, thereby assessing the reproducibility and precision of the motion control alone. Second, the targeting accuracy was assessed by imaging a polystyrene plate with randomly drilled holes and replicating the hole pattern by sonicating the observed hole locations on intact polystyrene plates and comparing the results. Third, the practicallyrealizable accuracy and precision were assessed by comparing the locations of transcranial, FUS-induced blood-brain-barrier disruption (BBBD) (observed through Gadolinium enhancement) to the intended targets in a retrospective analysis of animals sonicated for other experiments. Results: The evenly-spaced grids indicated that the precision was 0.11 +/− 0.05 mm. When image-guidance was included by targeting random locations, the accuracy was 0.5 +/− 0.2 mm. The effective accuracy in the four rodent brains assessed was 0.8 +/− 0.6 mm. In all cases, the error appeared normally distributed (p<0.05) in both orthogonal axes, though the left/right error was systematically greater than the superior/inferior error. Conclusions: The targeting accuracy of this device is sub-millimeter, suitable for many

  18. Neuroaesthetic Resonance

    DEFF Research Database (Denmark)

    Brooks, Anthony Lewis

    2013-01-01

    Neuroaesthetic Resonance emerged from a mature body of patient- centered gesture-control research investigating non-formal rehabilitation via ICT-enhanced-Art to question ‘Aesthetic Resonance’. Motivating participation, ludic engagement, and augmenting physical motion in non-formal (fun) treatment...... the unencumbered motion-to-computer-generated activities - ‘Music Making’, ‘Painting’, ‘Robotic’ and ‘Video Game’ control. A focus of this position paper is to highlight how Aesthetic Resonance, in this context, relates to the growing body of research on Neuroaesthetics to evolve Neuroaesthetic Resonance....

  19. Membrane transporters in focus. Observation of biological machines at work using Foerster resonance energy transfer; Membrantransporter im Fokus. Mit Foerster-Resonanz-Energie-Transfer biologische Maschinen bei der Arbeit verfolgen

    Energy Technology Data Exchange (ETDEWEB)

    Boersch, Michael [Universitaetsklinikum Jena (Germany). Arbeitsgebiet Mikroskopie-Methodik

    2011-09-15

    Biological nanomachines can be individually observed at work using a confocal fluorescence microscope. The velocity, directionality, and increment of rotary motors, such as the F{sub 0}F{sub 1}-ATP synthase, can be monitored via the internal distance measurements between specifically attached dye molecules based on Foerster resonance energy transfer (FRET). An electrokinetic trap can suppress the Brownian motion in solution and maintain accurately one membrane enzyme in focus.

  20. Ultrasound guided high-intensity focused ultrasound combined with gonadotropin releasing hormone analogue (GnRHa) ablating uterine leiomyoma with homogeneous hyperintensity on T2 weighted MR imaging.

    Science.gov (United States)

    Yang, Shenghua; Kong, Fanjing; Hou, Ruijie; Rong, Fengmei; Ma, Nana; Li, Shaoping; Yang, Jun

    2017-05-01

    The study aimed to evaluate the safety and efficiency of ultrasound-guided high-intensity focused ultrasound (USgHIFU) combined with gonadotropin-releasing hormone analogue (GnRHa)-ablating symptomatic uterine leiomyoma with homogeneous hyperintensity on T2 weighted MRI prospectively. A total of 34 patients with 42 symptomatic uterine leiomyomas with homogeneous hyperintensity on T2 weighted MRI were enrolled in our study. In the patient who had multiple uterine leiomyomas, only one dominant leiomyoma was treated. According to the principles of voluntariness, 18 patients underwent a 3-month therapy of GnRHa (once a month) before the high-intensity focused ultrasound (HIFU) treatment, while 16 patients received only HIFU treatment. Enhanced MRI was performed before and after GnRHa and HIFU treatment. Evaluation of the main indicators included treatment time, sonication time, treatment efficiency, non-perfused volume (NPV) (indicative of successful ablation) ratio and energy effect ratio; adverse events were also recorded. The treatment time and sonication time of the combination group were 102.0 min (55.8-152.2 min) and 25.4 min (12.2-34.1 min); however, they were 149.0 min (87.0-210.0 min) and 38.9 min (14.0-46.7 min) in the simple USgHIFU group. The treatment and sonication time for the combination group was significantly shorter than that for the simple USgHIFU group. Treatment efficiency, NPV ratio and energy effect ratio were 46.7 mm3 s-1 (28.5-95.8 mm3 s-1), 69.2 ± 29.8% (35.5-97.4%) and 9.9 KJ mm-3 (4.5-15.7 KJ mm-3) in the combination group, respectively; but, the lowest treatment efficiency, lowest NPV ratio and more energy effect ratio were observed in the simple HIFU group, which were 16.8 mm3 s-1 (8.9-32.9 mm3 s-1), 50.2 ± 27.3% (0-78.6%) and 23.8 KJ mm-3 (12.4-46.2 KJ mm-3), respectively. Pain scores in the combination group were 3.0 ± 0.5 points (2-4 points)-significantly less than the

  1. Magnetic Resonance Image Guided Radiation Therapy for External Beam Accelerated Partial-Breast Irradiation: Evaluation of Delivered Dose and Intrafractional Cavity Motion

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, Sahaja; Fischer-Valuck, Benjamin W.; Mazur, Thomas R.; Curcuru, Austen; Sona, Karl; Kashani, Rojano; Green, Olga; Ochoa, Laura; Mutic, Sasa; Zoberi, Imran; Li, H. Harold; Thomas, Maria A., E-mail: mthomas@radonc.wustl.edu

    2016-11-15

    Purpose: To use magnetic resonance image guided radiation therapy (MR-IGRT) for accelerated partial-breast irradiation (APBI) to (1) determine intrafractional motion of the breast surgical cavity; and (2) assess delivered dose versus planned dose. Methods and Materials: Thirty women with breast cancer (stages 0-I) who underwent breast-conserving surgery were enrolled in a prospective registry evaluating APBI using a 0.35-T MR-IGRT system. Clinical target volume was defined as the surgical cavity plus a 1-cm margin (excluding chest wall, pectoral muscles, and 5 mm from skin). No additional margin was added for the planning target volume (PTV). A volumetric MR image was acquired before each fraction, and patients were set up to the surgical cavity as visualized on MR imaging. To determine the delivered dose for each fraction, the electron density map and contours from the computed tomography simulation were transferred to the pretreatment MR image via rigid registration. Intrafractional motion of the surgical cavity was determined by applying a tracking algorithm to the cavity contour as visualized on cine MR. Results: Median PTV volume was reduced by 52% when using no PTV margin compared with a 1-cm PTV margin used conventionally. The mean (± standard deviation) difference between planned and delivered dose to the PTV (V95) was 0.6% ± 0.1%. The mean cavity displacement in the anterior–posterior and superior–inferior directions was 0.6 ± 0.4 mm and 0.6 ± 0.3 mm, respectively. The mean margin required for at least 90% of the cavity to be contained by the margin for 90% of the time was 0.7 mm (5th-95th percentile: 0-2.7 mm). Conclusion: Minimal intrafractional motion was observed, and the mean difference between planned and delivered dose was less than 1%. Assessment of efficacy and cosmesis of this MR-guided APBI approach is under way.

  2. Evaluation of the pain and local tenderness in bone metastasis treated with magnetic resonance-guided focused ultrasound surgery (MRgFUS)

    Science.gov (United States)

    Namba, Hirofumi; Kawasaki, Motohiro; Kato, Tomonari; Tani, Toshikazu; Ushida, Takahiro; Koizumi, Norihiro

    2017-03-01

    It has been reported that MRgFUS has pain palliative effects on the local pain in patients with bone metastasis. In general, a severity of pain has been evaluated using only subjective method with numerical rating scale (NRS) or visual analogue scale (VAS). It is important to evaluate local pain-palliative effects of MRgFUS treatment with objective and quantitative method. The aim of this study is to investigate changes in the severity of local pain of bone metastasis before and after MRgFUS treatments, measuring pressure pain threshold (PPT) using pressure algometer, and pain intensity using electrical stimulation device (the Pain Vision system) at most painful site of bone metastasis. We have conducted MRgFUS for pain palliation of bone metastasis for 8 patients, and evaluated the local tenderness quantitatively for 8 patients, and evaluated local pain intensity for 7 patients. Before the treatments, PPTs were 106.3kPa [40.0-431.5] at metastatic site and 344.8 kPa [206.0-667.0] at normal control site, which showed a significant difference. The PPTs at metastatic site shows a significant increase from 106.3 kPa [40.0-431.5] at the baseline to 270.5 kPa [93.5-533.5] at 3 months after the treatment. The NRS score shows a significant decrease from 6.0 [4-8] at baseline to 1 [0-3] at 3 months after the treatment. Similarly, the pain intensity shows a significant decrease 245 [96.3-888.7] at baseline to 55.9 [2.8-292] at 3 months after the treatment. The results of our study illustrate the pain-relieving effects of MRgFUS for the treatment of painful bone metastasis. PPT might be a useful parameter not only for assessing a treatment's effect, but also for the decision of the painful area to treat with MRgFUS. Pain Vision seems to be useful for quantitative and objective evaluation of local pain of painful bone metastasis.

  3. Efficacy of single-dose gonadotropin-releasing hormone agonist administration prior to magnetic resonance-guided focused ultrasound surgery for symptomatic uterine fibroids.

    Science.gov (United States)

    Park, Hyun; Yoon, Sang Wook

    2017-08-01

    To investigate the effects of a single-dose GnRHa on the thermal ablation of MRgFUS in women with symptomatic fibroids. In this pilot study, a single-dose GnRHa was administered in 17 patients with a total of 20 fibroids. Volume and scaled signal intensity (SSI) as an objective marker of fluid contents were prospectively followed up with serial MR scans. The control group of 17 patients with 19 fibroids were retrospectively enrolled and compared with GnRHa group in terms of non-perfused volume (NPV) and thermal dosimetry to assess the efficiency of thermal ablation. About 29 days after GnRHa administration, SSI and volume of fibroids were reduced by 55.1 and 10.6%, respectively (p < 0.05) but no adverse events were reported. NPV per unit energy (0.046 cm3/J ± 0.026 vs. 0.031 cm3/J ± 0.018, p = 0.041) was larger and SSI (8.4 ± 8.0 vs. 13.9 ± 12.0, p = 0.053) was lower in GnRHa group. Linear regression analysis showed that these two parameters were in a reverse correlation (p = 0.011). GnRHa is supposed to reduce the fluid contents of fibroids including blood vessels and enhance the tissue responsiveness to thermal energy. A single dose prior to MRgFUS has the potential to improve treatment efficiency, while avoiding the side effects of multiple doses of GnRHa.

  4. Magnetic Resonance Imaging-Guided Transurethral Ultrasound Ablation of Prostate Tissue in Patients with Localized Prostate Cancer: A Prospective Phase 1 Clinical Trial.

    Science.gov (United States)

    Chin, Joseph L; Billia, Michele; Relle, James; Roethke, Matthias C; Popeneciu, Ionel V; Kuru, Timur H; Hatiboglu, Gencay; Mueller-Wolf, Maya B; Motsch, Johann; Romagnoli, Cesare; Kassam, Zahra; Harle, Christopher C; Hafron, Jason; Nandalur, Kiran R; Chronik, Blaine A; Burtnyk, Mathieu; Schlemmer, Heinz-Peter; Pahernik, Sascha

    2016-09-01

    Magnetic resonance imaging-guided transurethral ultrasound ablation (MRI-TULSA) is a novel minimally invasive technology for ablating prostate tissue, potentially offering good disease control of localized cancer and low morbidity. To determine the clinical safety and feasibility of MRI-TULSA for whole-gland prostate ablation in a primary treatment setting of localized prostate cancer (PCa). A single-arm prospective phase 1 study was performed at three tertiary referral centers in Canada, Germany, and the United States. Thirty patients (median age: 69 yr; interquartile range [IQR]: 67-71 yr) with biopsy-proven low-risk (80%) and intermediate-risk (20%) PCa were treated and followed for 12 mo. MRI-TULSA treatment was delivered with the therapeutic intent of conservative whole-gland ablation including 3-mm safety margins and 10% residual viable prostate expected around the capsule. Primary end points were safety (adverse events) and feasibility (technical accuracy and precision of conformal thermal ablation). Exploratory outcomes included quality of life, prostate-specific antigen (PSA), and biopsy at 12 mo. Median treatment time was 36min (IQR: 26-44) and prostate volume was 44ml (IQR: 38-48). Spatial control of thermal ablation was ±1.3mm on MRI thermometry. Common Terminology Criteria for Adverse Events included hematuria (43% grade [G] 1; 6.7% G2), urinary tract infections (33% G2), acute urinary retention (10% G1; 17% G2), and epididymitis (3.3% G3). There were no rectal injuries. Median pretreatment International Prostate Symptom Score 8 (IQR: 5-13) returned to 6 (IQR: 4-10) at 3 mo (mean change: -2; 95% confidence interval [CI], -4 to 1). Median pretreatment International Index of Erectile Function 13 (IQR: 6-28) recovered to 13 (IQR: 5-25) at 12 mo (mean change: -1; 95% CI, -5 to 3). Median PSA decreased 87% at 1 mo and was stable at 0.8 ng/ml (IQR: 0.6-1.1) to 12 mo. Positive biopsies showed 61% reduction in total cancer length, clinically significant

  5. Image-guided virtual autopsy findings of gunshot victims performed with multi-slice computed tomography and magnetic resonance imaging and subsequent correlation between radiology and autopsy findings.

    Science.gov (United States)

    Thali, Michael J; Yen, Kathrin; Vock, Peter; Ozdoba, Christoph; Kneubuehl, Beat P; Sonnenschein, Martin; Dirnhofer, Richard

    2003-12-17

    Because the use of radiology in modern forensic medicine has been, until today, mostly restricted to conventional X-rays, which reduces a 3D body to a 2D projection, a detailed 3D documentation of a gunshot's wound ballistic effects was not possible. The aim of our study was to evaluate whether the progress in imaging techniques over the last years has made it possible to establish an observer-independent and reproducible forensic assessment using multi-slice computed tomography (MSCT) and magnetic resonance imaging (MRI) technologies for the documentation and analysis of gunshot wounds. The bodies of eight gunshot victims were scanned by MSCT and by MRI; the data of these imaging techniques were post-processed on a workstation, interpreted and subsequently correlated with the findings of classical autopsy. With the spiral CT and MRI examinations and the subsequent 2D multi-planar reformation (MPR) and 3D shaded surface display (SSD) reconstruction, the entire gunshot-created complex skull fractures and brain injuries (such as wound channels and deeply-driven bone splinters) could be documented in complete and graphic detail. CT and MRI also documented vital reaction to the gunshot by demonstrating air emboli in the heart and blood vessels and the classic pattern of blood aspiration to the lung. Gunshot residues deposited within and under the skin were visible. In conclusion, we think that the radiological methods of MSCT and MRI have the potential to become a routine "virtual autopsy" tool in the future. Bullets and relevant histological samples from specific sites then might be won in image-guided minimally invasive fashion via percutaneous biopsy. The rapid application of developing radiological methods may lead to new horizons in forensic documentation and intravital as well as postmortem examination.

  6. Dose Effect Relationship for Late Side Effects of the Rectum and Urinary Bladder in Magnetic Resonance Image-Guided Adaptive Cervix Cancer Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Georg, Petra, E-mail: petra.georg@akhwien.at [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Poetter, Richard; Georg, Dietmar; Lang, Stefan; Dimopoulos, Johannes C.A.; Sturdza, Alina E.; Berger, Daniel; Kirisits, Christian [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Doerr, Wolfgang [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Department of Radiotherapy and Radiation Oncology, Medical Faculty Carl Gustav Carus, University of Technology Dresden, Dresden (Germany)

    2012-02-01

    Purpose: To establish dose-response relationships for late side effects of the rectum and bladder in cervix cancer patients after magnetic resonance image-guided adaptive brachytherapy (IGABT). Methods and Materials: A cohort of 141 patients was treated with 45 to 50.4 Gy with or without cisplatin plus 4 fractions of 7 Gy IGABT. Doses for the most exposed 2, 1, and 0.1-cm{sup 3} (D{sub 2cc}, D{sub 1cc}, D{sub 0.1cc}) volumes of the rectum and bladder were converted into the equivalent dose in 2 Gy fractions (EQD2), using a linear quadratic model ({alpha}/{beta} = 3 Gy). Late side effects were prospectively assessed (using late effects in normal tissues subjective, objective, management and analytic [LENT SOMA]) scales. Dose-response relationships were determined by logit analyses. Results: Eleven patients developed rectal side effects, and 23 patients had urinary side effects. A significant dose effect was found for all rectal dose-volume histogram (DVH) parameters for patients with side effect grades of 1 to 4 but was only significant for D{sub 2cc} and D{sub 1cc} for grades {>=}2. The ED10 values for D{sub 2cc} were 73 Gy for grades 1 to 4 and 78 Gy for grades 2 to 4 rectal morbidity. For bladder side effects, a significant dose effect was shown for all DVH parameters for complication grades {>=}2; the respective ED10 was 101 Gy. Conclusions: Well-defined dose-response curves could be established for D{sub 2cc} in the rectum and the urinary bladder.

  7. Effects of variable power on tissue ablation dynamics during magnetic resonance-guided laser-induced thermal therapy with the Visualase system.

    Science.gov (United States)

    Munier, Sean M; Hargreaves, Eric L; Patel, Nitesh V; Danish, Shabbar F

    2017-09-18

    Magnetic resonance-guided laser-induced thermal therapy (MRgLITT) is a minimally invasive procedure used to treat various intracranial pathologies. This study investigated the effects of variable power on maximal estimated thermal damage during ablation and duration required to reach maximal ablation. All ablations were performed using the Visualase Thermal Therapy System (Medtronic Inc., Minneapolis, Minnesota), which uses a 980 nm diffusing tip diode laser. Cases were stratified into low, medium and high power. Maximal thermal damage estimate (TDE max ) achieved in a single plane and time to reach maximal damage (t tdemax ) were measured and compared between groups using a 2×3 Fixed Factor Analysis of Covariance. Ablation area change for cases in which an initial thermal dose was followed by a subsequent dose, with increased power, was also assessed. We used real-time ablation data from 93 patients across various intracranial pathologies. t tdemax (mean ± SEM) decreased linearly as power increased (low: 139.2 ± 10.4 s, medium: 127.5 ± 4.3 s, high: 103.7 ± 5.8 s). In cases where a second thermal dose was delivered at higher power, the TDE expanded an average of 51.4 mm 2 beyond the initial TDE generated by the first ablation, with the second ablation approaching TDE max at a higher rate than the initial ablation. Increased power results in a larger TDE max and an increased ablation rate. In cases where an initial thermal dose does not fully ablate the target lesion, a second ablation at higher power can increase the area of ablation with an increased ablation rate.

  8. TU-AB-BRA-10: Treatment of Gastric MALT Lymphoma Utilizing a Magnetic Resonance Image-Guided Radiation Therapy (MR-IGRT) System: Evaluation of Gating Feasibility

    Energy Technology Data Exchange (ETDEWEB)

    Mazur, T; Gach, H; Chundury, A; Fischer-Valuck, B; Huang, J; Thomas, M; Green, O [Washington University School of Medicine, St. Louis, MO (United States)

    2016-06-15

    Purpose: To evaluate the feasibility of real-time, real-anatomy tracking and gating for gastric lymphoma patients treated with magnetic resonance image-guided radiation therapy (MR-IGRT) Methods: Over the last 2 years, 8 patients with gastric lymphoma were treated with 0.3-T, Co-60 MR-IGRT. Post-treatment analysis of real-time cine imaging in the sagittal plane during each patient’s treatment revealed significant motion of the stomach. While this motion was accounted for with generous PTV margins, the system’s capability for real-time, real-anatomy tracking could be used to reduce treatment margins by gating. However, analysis was needed for the feasibility of gating using only the single available sagittal imaging plane. While any plane may be chosen, if the stomach moves differently where it is not being observed, there may potentially be a mistreatment. To that end, imaging with healthy volunteers was done to ascertain stomach motion over 2–4 min by analyzing multiple parallel sagittal and coronal planes 0.75 cm apart. The stomach was contoured on every slice, and the mean displacement between pairs of contour centroids was used to determine the amount of overall motion. Results: The mean displacement of the centroid in the image plane was 4.3 ± 0.7 mm. The greatest observed motion was more medial with respect to the patient, and less motion laterally, which implies that gating on a plane located closer to MRI isocenter will provide the more conservative scenario as it will turn the radiation delivery off when the stomach is observed to move outside a predetermined boundary. Conclusion: The stomach was observed to move relatively uniformly throughout, with maximum extent of motion closer to where most MRI systems have the best spatial integrity (near isocenter). Analysis of possible PTV margins from the healthy volunteer study (coupled with previous patient data on interfraction volumetric stomach deformation) is pending.

  9. Effect of Care Guided by Cardiovascular Magnetic Resonance, Myocardial Perfusion Scintigraphy, or NICE Guidelines on Subsequent Unnecessary Angiography Rates: The CE-MARC 2 Randomized Clinical Trial.

    Science.gov (United States)

    Greenwood, John P; Ripley, David P; Berry, Colin; McCann, Gerry P; Plein, Sven; Bucciarelli-Ducci, Chiara; Dall'Armellina, Erica; Prasad, Abhiram; Bijsterveld, Petra; Foley, James R; Mangion, Kenneth; Sculpher, Mark; Walker, Simon; Everett, Colin C; Cairns, David A; Sharples, Linda D; Brown, Julia M

    2016-09-13

    Among patients with suspected coronary heart disease (CHD), rates of invasive angiography are considered too high. To test the hypothesis that among patients with suspected CHD, cardiovascular magnetic resonance (CMR)-guided care is superior to National Institute for Health and Care Excellence (NICE) guidelines-directed care and myocardial perfusion scintigraphy (MPS)-guided care in reducing unnecessary angiography. Multicenter, 3-parallel group, randomized clinical trial using a pragmatic comparative effectiveness design. From 6 UK hospitals, 1202 symptomatic patients with suspected CHD and a CHD pretest likelihood of 10% to 90% were recruited. First randomization was November 23, 2012; last 12-month follow-up was March 12, 2016. Patients were randomly assigned (240:481:481) to management according to UK NICE guidelines or to guided care based on the results of CMR or MPS testing. The primary end point was protocol-defined unnecessary coronary angiography (normal fractional flow reserve >0.8 or quantitative coronary angiography [QCA] showing no percentage diameter stenosis ≥70% in 1 view or ≥50% in 2 orthogonal views in all coronary vessels ≥2.5 mm diameter) within 12 months. Secondary end points included positive angiography, major adverse cardiovascular events (MACEs), and procedural complications. Among 1202 symptomatic patients (mean age, 56.3 years [SD, 9.0]; women, 564 [46.9%] ; mean CHD pretest likelihood, 49.5% [SD, 23.8%]), number of patients with invasive coronary angiography after 12 months was 102 in the NICE guidelines group (42.5% [95% CI, 36.2%-49.0%])], 85 in the CMR group (17.7% [95% CI, 14.4%-21.4%]); and 78 in the MPS group (16.2% [95% CI, 13.0%-19.8%]). Study-defined unnecessary angiography occurred in 69 (28.8%) in the NICE guidelines group, 36 (7.5%) in the CMR group, and 34 (7.1%) in the MPS group; adjusted odds ratio of unnecessary angiography: CMR group vs NICE guidelines group, 0.21 (95% CI, 0.12-0.34, P angiography proportions

  10. International consensus on use of focused ultrasound for painful bone metastases : Current status and future directions

    NARCIS (Netherlands)

    Huisman, Merel; ter Haar, Gail; Napoli, Alessandro; Hananel, Arik; Ghanouni, Pejman; Lövey, György; Nijenhuis, Robbert J; van den Bosch, Maurice A A J; Rieke, Viola; Majumdar, Sharmila; Marchetti, Luca; Pfeffer, Raphael M; Hurwitz, Mark D

    2015-01-01

    Focused ultrasound surgery (FUS), in particular magnetic resonance guided FUS (MRgFUS), is an emerging non-invasive thermal treatment modality in oncology that has recently proven to be effective for the palliation of metastatic bone pain. A consensus panel of internationally recognised experts in

  11. Intracranial inertial cavitation threshold and thermal ablation lesion creation using MRI-guided 220-kHz focused ultrasound surgery: preclinical investigation.

    Science.gov (United States)

    Xu, Zhiyuan; Carlson, Carissa; Snell, John; Eames, Matt; Hananel, Arik; Lopes, M Beatriz; Raghavan, Prashant; Lee, Cheng-Chia; Yen, Chun-Po; Schlesinger, David; Kassell, Neal F; Aubry, Jean-Francois; Sheehan, Jason

    2015-01-01

    In biological tissues, it is known that the creation of gas bubbles (cavitation) during ultrasound exposure is more likely to occur at lower rather than higher frequencies. Upon collapsing, such bubbles can induce hemorrhage. Thus, acoustic inertial cavitation secondary to a 220-kHz MRI-guided focused ultrasound (MRgFUS) surgery is a serious safety issue, and animal studies are mandatory for laying the groundwork for the use of low-frequency systems in future clinical trials. The authors investigate here the in vivo potential thresholds of MRgFUS-induced inertial cavitation and MRgFUS-induced thermal coagulation using MRI, acoustic spectroscopy, and histology. Ten female piglets that had undergone a craniectomy were sonicated using a 220-kHz transcranial MRgFUS system over an acoustic energy range of 5600-14,000 J. For each piglet, a long-duration sonication (40-second duration) was performed on the right thalamus, and a short sonication (20-second duration) was performed on the left thalamus. An acoustic power range of 140-300 W was used for long-duration sonications and 300-700 W for short-duration sonications. Signals collected by 2 passive cavitation detectors were stored in memory during each sonication, and any subsequent cavitation activity was integrated within the bandwidth of the detectors. Real-time 2D MR thermometry was performed during the sonications. T1-weighted, T2-weighted, gradient-recalled echo, and diffusion-weighted imaging MRI was performed after treatment to assess the lesions. The piglets were killed immediately after the last series of posttreatment MR images were obtained. Their brains were harvested, and histological examinations were then performed to further evaluate the lesions. Two types of lesions were induced: thermal ablation lesions, as evidenced by an acute ischemic infarction on MRI and histology, and hemorrhagic lesions, associated with inertial cavitation. Passive cavitation signals exhibited 3 main patterns identified as

  12. Overview of ligand versus metal centered redox reactions in tetraaza macrocyclic complexes of nickel with a focus on electron paramagnetic resonance studies

    OpenAIRE

    Telser,Joshua

    2010-01-01

    Copper(II) (3d9, S = 1/2) complexes are stable and widely investigated by electron paramagnetic resonance (EPR) spectroscopy. In contrast, isoelectronic nickel(I) is much less common and much less investigated. Nickel(I), however, is of biological interest as the active site of methyl coenzyme M reductase (MCR) contains a tetraaza macrocyclic ligand, F430, which coordinates NiI in its active form, MCRred1. As result, the redox behavior and spectroscopy of tetraaza macrocyclic complexes of nic...

  13. Magnetic resonance imaging-targeted, 3D transrectal ultrasound-guided fusion biopsy for prostate cancer: Quantifying the impact of needle delivery error on diagnosis.

    Science.gov (United States)

    Martin, Peter R; Cool, Derek W; Romagnoli, Cesare; Fenster, Aaron; Ward, Aaron D

    2014-07-01

    Magnetic resonance imaging (MRI)-targeted, 3D transrectal ultrasound (TRUS)-guided "fusion" prostate biopsy intends to reduce the ∼23% false negative rate of clinical two-dimensional TRUS-guided sextant biopsy. Although it has been reported to double the positive yield, MRI-targeted biopsies continue to yield false negatives. Therefore, the authors propose to investigate how biopsy system needle delivery error affects the probability of sampling each tumor, by accounting for uncertainties due to guidance system error, image registration error, and irregular tumor shapes. T2-weighted, dynamic contrast-enhanced T1-weighted, and diffusion-weighted prostate MRI and 3D TRUS images were obtained from 49 patients. A radiologist and radiology resident contoured 81 suspicious regions, yielding 3D tumor surfaces that were registered to the 3D TRUS images using an iterative closest point prostate surface-based method to yield 3D binary images of the suspicious regions in the TRUS context. The probabilityP of obtaining a sample of tumor tissue in one biopsy core was calculated by integrating a 3D Gaussian distribution over each suspicious region domain. Next, the authors performed an exhaustive search to determine the maximum root mean squared error (RMSE, in mm) of a biopsy system that gives P ≥ 95% for each tumor sample, and then repeated this procedure for equal-volume spheres corresponding to each tumor sample. Finally, the authors investigated the effect of probe-axis-direction error on measured tumor burden by studying the relationship between the error and estimated percentage of core involvement. Given a 3.5 mm RMSE for contemporary fusion biopsy systems,P ≥ 95% for 21 out of 81 tumors. The authors determined that for a biopsy system with 3.5 mm RMSE, one cannot expect to sample tumors of approximately 1 cm(3) or smaller with 95% probability with only one biopsy core. The predicted maximum RMSE giving P ≥ 95% for each tumor was consistently greater when using

  14. Magnetic resonance imaging-targeted, 3D transrectal ultrasound-guided fusion biopsy for prostate cancer: Quantifying the impact of needle delivery error on diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Peter R., E-mail: pmarti46@uwo.ca [Department of Medical Biophysics, The University of Western Ontario, London, Ontario N6A 3K7 (Canada); Cool, Derek W. [Department of Medical Imaging, The University of Western Ontario, London, Ontario N6A 3K7, Canada and Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 3K7 (Canada); Romagnoli, Cesare [Department of Medical Imaging, The University of Western Ontario, London, Ontario N6A 3K7 (Canada); Fenster, Aaron [Department of Medical Biophysics, The University of Western Ontario, London, Ontario N6A 3K7 (Canada); Department of Medical Imaging, The University of Western Ontario, London, Ontario N6A 3K7 (Canada); Robarts Research Institute, The University of Western Ontario, London, Ontario N6A 3K7 (Canada); Ward, Aaron D. [Department of Medical Biophysics, The University of Western Ontario, London, Ontario N6A 3K7 (Canada); Department of Oncology, The University of Western Ontario, London, Ontario N6A 3K7 (Canada)

    2014-07-15

    Purpose: Magnetic resonance imaging (MRI)-targeted, 3D transrectal ultrasound (TRUS)-guided “fusion” prostate biopsy intends to reduce the ∼23% false negative rate of clinical two-dimensional TRUS-guided sextant biopsy. Although it has been reported to double the positive yield, MRI-targeted biopsies continue to yield false negatives. Therefore, the authors propose to investigate how biopsy system needle delivery error affects the probability of sampling each tumor, by accounting for uncertainties due to guidance system error, image registration error, and irregular tumor shapes. Methods: T2-weighted, dynamic contrast-enhanced T1-weighted, and diffusion-weighted prostate MRI and 3D TRUS images were obtained from 49 patients. A radiologist and radiology resident contoured 81 suspicious regions, yielding 3D tumor surfaces that were registered to the 3D TRUS images using an iterative closest point prostate surface-based method to yield 3D binary images of the suspicious regions in the TRUS context. The probabilityP of obtaining a sample of tumor tissue in one biopsy core was calculated by integrating a 3D Gaussian distribution over each suspicious region domain. Next, the authors performed an exhaustive search to determine the maximum root mean squared error (RMSE, in mm) of a biopsy system that gives P ≥ 95% for each tumor sample, and then repeated this procedure for equal-volume spheres corresponding to each tumor sample. Finally, the authors investigated the effect of probe-axis-direction error on measured tumor burden by studying the relationship between the error and estimated percentage of core involvement. Results: Given a 3.5 mm RMSE for contemporary fusion biopsy systems,P ≥ 95% for 21 out of 81 tumors. The authors determined that for a biopsy system with 3.5 mm RMSE, one cannot expect to sample tumors of approximately 1 cm{sup 3} or smaller with 95% probability with only one biopsy core. The predicted maximum RMSE giving P ≥ 95% for each

  15. Magnetic resonance texture parameters are associated with ablation efficiency in MR-guided high-intensity focussed ultrasound treatment of uterine fibroids.

    Science.gov (United States)

    Hocquelet, Arnaud; Denis de Senneville, Baudouin; Frulio, Nora; Salut, Cécile; Bouzgarrou, Mounir; Papadopoulos, Panteleimon; Trillaud, Hervé

    2016-10-28

    The objective of this study is to assess the association between texture parameter analysis derived from T2-weighted images and efficiency of magnetic resonance-guided focussed ultrasound (MRgFUS) ablation for the treatment of uterine fibroids. Fifty-five women treated by MRgFUS were included in this retrospective analysis. Texture parameters were calculated using three 2D regions of interest placed on three consecutive slices on the same sagittal 3D T2-weighted images obtained at the beginning of MRgFUS ablation. Using uni- and multi-variate linear regression, texture parameters, fibroids/muscular T2W ratio (T2Wr), Funaki type, and fibroid depth were correlated with ablation efficiency, defined as the ratio of non-perfused volume (NPV) on post-treatment contrast-enhanced MRI by total volume of treatment-cell sizes used. Inter-rater reproducibility for texture analysis was assessed using variation coefficients. The mean total treatment cell volume was 49.5 (±30) ml, corresponding to a mean NPV of 57.2 (±57) ml (28%). The mean ablation efficiency was 1.14 (±0.7), with a range of 0.03-3.6. In addition to fibroid/muscular T2Wr, seven of the 14 texture parameters were significantly correlated with ablation efficiency: mean signal intensity (p = .047); Skewness (p = .03); Kurtosis (p = .015); mean uniformity (p = .052); mean sum of square (p = .045); mean sum entropy (p = .021) and mean entropy (p = .051). In multivariate linear regression, fibroid/muscular T2Wr and sum of entropy were associated with ablation efficiency. The inter-rater coefficient of variation for sum entropy was 2.6%. Uterine fibroid texture parameters provide complementary information to T2Wr, and are associated with MRgFUS efficiency. Key points Mean sum entropy is negatively correlated with MRgFUS efficiency (ρ = -0.307, p = .021). Fibroids/muscular T2-weighted ratio and entropy are associated with MRgFUS efficiency. Texture parameters are better predictors

  16. Magnetic Resonance Imaging-Guided Multi-Drug Chemotherapy and Photothermal Synergistic Therapy with pH and NIR-Stimulation Release.

    Science.gov (United States)

    Yang, Ji-Chun; Chen, Yang; Li, Yu-Hao; Yin, Xue-Bo

    2017-07-12

    The combination of multidrug chemotherapy and photothermal therapy (PTT) enhances cancer therapeutic efficacy. Herein, we develop a simple and smart pH/NIR dual-stimulus-responsive degradable mesoporous CoFe2O4@PDA@ZIF-8 sandwich nanocomposite. The mesoporous CoFe2O4 core acts as T2-weighted magnetic resonance (MR) imaging probe, PTT agent, and loading platform of hydrophilic doxorubicin (DOX). A polydopamine (PDA) layer is used to avoid the premature leakage of DOX before arriving at tumor site, enhance PTT efficiency, and facilitate the integration of ZIF-8 (a kind of metal-organic framework). The ZIF-8 shell serves to encapsulate hydrophobic camptothecin (CPT) and as the switch for the pH and NIR stimulation-responsive release of the two drugs. Therefore, T2-weighted MR imaging-guided multidrug chemotherapy and PTT synergistic treatment is achieved. Two kinds of anticancer drugs, hydrophilic DOX and hydrophobic CPT, are successfully loaded in CoFe2O4 and ZIF-8, respectively, so no mutual interference between the two drugs exists. A unique two-stage stepwise release process is exhibited for CPT and DOX with an interval of 12 h to improve the anticancer efficacy under the acidic microenvironment of tumor tissue. NIR irradiation achieves the burst drug-release and PTT after laser stimulation, simultaneously. With this smart design, high drug concentration is achieved at the tumor site by quick release, especially for the therapeutic drugs that show nonlinear pharmacokinetics, and PTT is integrated efficiently. Furthermore, negligible biotoxicity and a remarkable synergic antitumor effect of the hybrid nanocomposites are validated by HepG2 cells and tumor-bearing mice as models. Our multidrug delivery-releasing composite improves tumor therapeutic efficiency significantly compared with a single-drug chemotherapy system. The simple multifunctional composite system can be applied as an effective platform for personal nanomedicine with diagnosis, smart drug delivery

  17. Treatment of Locally Advanced Vaginal Cancer With Radiochemotherapy and Magnetic Resonance Image-Guided Adaptive Brachytherapy: Dose-Volume Parameters and First Clinical Results

    Energy Technology Data Exchange (ETDEWEB)

    Dimopoulos, Johannes C.A. [Department of Radiation Oncology, Metropolitan Hospital, Athens (Greece); Schmid, Maximilian P., E-mail: maximilian.schmid@akhwien.at [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Poetter, Richard [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria)

    2012-04-01

    Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45-50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model ({alpha}/{beta} = 10 Gy for tumor; {alpha}/{beta} = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV ({+-} 1 standard deviation) at diagnosis was 45.3 ({+-}30) cm{sup 3}, and the mean GTV at brachytherapy was 10 ({+-}14) cm{sup 3}. The mean D90 for the HRCTV was 86 ({+-}13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 ({+-}20) Gy, 76 ({+-}16) Gy, 70 ({+-}9) Gy, and 60 ({+-}9) Gy, respectively. After a median follow-up of 43 months (range, 19-87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and

  18. Clinical outcomes and cost-effectiveness of brief guided parent-delivered cognitive behavioural therapy and solution-focused brief therapy for treatment of childhood anxiety disorders: a randomised controlled trial.

    Science.gov (United States)

    Creswell, Cathy; Violato, Mara; Fairbanks, Hannah; White, Elizabeth; Parkinson, Monika; Abitabile, Gemma; Leidi, Alessandro; Cooper, Peter J

    2017-07-01

    Half of all lifetime anxiety disorders emerge before age 12 years; however, access to evidence-based psychological therapies for affected children is poor. We aimed to compare the clinical outcomes and cost-effectiveness of two brief psychological treatments for children with anxiety referred to routine child mental health settings. We hypothesised that brief guided parent-delivered cognitive behavioural therapy (CBT) would be associated with better clinical outcomes than solution-focused brief therapy and would be cost-effective. We did this randomised controlled trial at four National Health Service primary child and mental health services in Oxfordshire, UK. Children aged 5-12 years referred for anxiety difficulties were randomly allocated (1:1), via a secure online minimisation tool, to receive brief guided parent-delivered CBT or solution-focused brief therapy, with minimisation for age, sex, anxiety severity, and level of parental anxiety. The allocation sequence was not accessible to the researcher enrolling participants or to study assessors. Research staff who obtained outcome measurements were masked to group allocation and clinical staff who delivered the intervention did not measure outcomes. The primary outcome was recovery, on the basis of Clinical Global Impressions of Improvement (CGI-I). Parents recorded patient-level resource use. Quality-adjusted life-years (QALYs) for use in cost-utility analysis were derived from the Child Health Utility 9D. Assessments were done at baseline (before randomisation), after treatment (primary endpoint), and 6 months after treatment completion. We did analysis by intention to treat. This trial is registered with the ISCRTN registry, number ISRCTN07627865. Between March 23, 2012, and March 31, 2014, we randomly assigned 136 patients to receive brief guided parent-delivered CBT (n=68) or solution-focused brief therapy (n=68). At the primary endpoint assessment (June, 2012, to September, 2014), 40 (59%) children in

  19. HBR guides

    CERN Document Server

    Duarte, Nancy; Dillon, Karen

    2015-01-01

    Master your most pressing professional challenges with this seven-volume set that collects the smartest best practices from leading experts all in one place. "HBR Guide to Better Business Writing" and "HBR Guide to Persuasive Presentations" help you perfect your communication skills; "HBR Guide to Managing Up and Across" and "HBR Guide to Office Politics" show you how to build the best professional relationships; "HBR Guide to Finance Basics for Managers" is the one book you'll ever need to teach you about the numbers; "HBR Guide to Project Management" addresses tough questions such as how to manage stakeholder expectations and how to manage uncertainty in a complex project; and "HBR Guide to Getting the Right Work Done" goes beyond basic productivity tips to teach you how to prioritize and focus on your work. This specially priced set of the most popular books in the series makes a perfect gift for aspiring leaders looking for trusted advice. Arm yourself with the advice you need to succeed on the job, from ...

  20. Comparison Between CT and MR Images as More Favorable Reference Data Sets for Fusion Imaging-Guided Radiofrequency Ablation or Biopsy of Hepatic Lesions: A Prospective Study with Focus on Patient's Respiration.

    Science.gov (United States)

    Cha, Dong Ik; Lee, Min Woo; Kang, Tae Wook; Oh, Young-Taek; Jeong, Ja-Yeon; Chang, Jung-Woo; Ryu, Jiwon; Lee, Kyong Joon; Kim, Jaeil; Bang, Won-Chul; Shin, Dong Kuk; Choi, Sung Jin; Koh, Dalkwon; Kim, Kyunga

    2017-10-01

    To identify the more accurate reference data sets for fusion imaging-guided radiofrequency ablation or biopsy of hepatic lesions between computed tomography (CT) and magnetic resonance (MR) images. This study was approved by the institutional review board, and written informed consent was received from all patients. Twelve consecutive patients who were referred to assess the feasibility of radiofrequency ablation or biopsy were enrolled. Automatic registration using CT and MR images was performed in each patient. Registration errors during optimal and opposite respiratory phases, time required for image fusion and number of point locks used were compared using the Wilcoxon signed-rank test. The registration errors during optimal respiratory phase were not significantly different between image fusion using CT and MR images as reference data sets (p = 0.969). During opposite respiratory phase, the registration error was smaller with MR images than CT (p = 0.028). The time and the number of points locks needed for complete image fusion were not significantly different between CT and MR images (p = 0.328 and p = 0.317, respectively). MR images would be more suitable as the reference data set for fusion imaging-guided procedures of focal hepatic lesions than CT images.

  1. Evidence-based solution-focused care for school-age children experiencing cyberbullying: using the Omaha System to guide and document psychiatric nursing interventions.

    Science.gov (United States)

    Kvarme, Lisbeth Gravdal; Monsen, Karen A; Eboh, Winifred Oluchukwu

    2014-03-01

    Cyberbullying is a global phenomenon. The experiences of bullied children are the same across cultures and languages, and psychiatric nursing interventions are known to be effective. It is critical to widely disseminate effective interventions to identify and address cyberbullying. Therefore, evidence-based care plans addressing cyberbullying at the individual and community levels were developed using the Omaha System, a terminology that is used internationally to guide and document care. This article presents a case study in which an evidence-based intervention was used to help a bullied child arrive at a solution, and demonstrates the use of the Omaha System to document evidence-based cyberbullying interventions with individuals and communities. Copyright 2014, SLACK Incorporated.

  2. NMR guided focused ultrasound for myoma therapy - results from the first radiology-gynecology expert meeting; Magnetresonanz-gefuehrter fokussierter Ultraschall zur Myombehandlung. Ergebnisse des ersten radiologisch-gynaekologischen Expertentreffens

    Energy Technology Data Exchange (ETDEWEB)

    Beck, A. [Charite Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Berlin (Germany). Klinik fuer Strahlenheilkunde; Charite Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Berlin (Germany). Inst. fuer Radiologie; David, M. [Charite Universitaetsmedizin Berlin, Campus Virchow-Klinikum, Berlin (Germany). Klinik fuer Gynaekologie; Kroencke, T. [Charite Universitaetsmedizin Berlin, Campus Charite Mitte, Berlin (Germany). Klinik fuer Strahlenheilkunde; Charite Universitaetsmedizin Berlin, Campus Charite Mitte, Berlin (Germany). Inst. fuer Radiologie

    2013-05-15

    The contribution on the results from the first radiology-gynecology expert meeting concerning NMR guided focused ultrasound (MRgFUS) for myoma therapy covers the following topics: structural prerequisites for MRgFUS therapy; required examinations before MRgFUS therapy; indication for MRgFUS therapy; success criteria for the MRgFUS therapy; contraindications; MRgFUS therapy for patients that want to have children; side effects and complications of MRgFUS therapy; post-examination after MRgFUS therapy.

  3. Outreach and Prevention Staff Focus Guide. Building Bridges: Supporting the Psychological Health and Traumatic Brain Injury Needs of Military and Veteran Families

    Science.gov (United States)

    2010-01-01

    DCoE Family Initiatives Sesame Street: Talk, Listen, Connect Sesame Street’s Talk, Listen, Connect, is a bilingual educational outreach initiative...and early childhood professionals offer some tips and strategies for families. Operation Parenting Edge These brochures focus on the unique...Early Childhood Univ. of Minnesota’s Children, Youth and Family Consortium: Early Childhood addresses individual, family and

  4. Development of patient-controlled respiratory gating system based on visual guidance for magnetic-resonance image-guided radiation therapy.

    Science.gov (United States)

    Kim, Jung-In; Lee, Hanyoung; Wu, Hong-Gyun; Chie, Eui Kyu; Kang, Hyun-Cheol; Park, Jong Min

    2017-09-01

    The aim of this study is to develop a visual guidance patient-controlled (VG-PC) respiratory gating system for respiratory-gated magnetic-resonance image-guided radiation therapy (MR-IGRT) and to evaluate the performance of the developed system. The near-real-time cine planar MR image of a patient acquired during treatment was transmitted to a beam projector in the treatment room through an optical fiber cable. The beam projector projected the cine MR images inside the bore of the ViewRay system in order to be visible to a patient during treatment. With this visual information, patients voluntarily controlled their respiration to put the target volume into the gating boundary (gating window). The effect of the presence of the beam projector in the treatment room on the image quality of the MRI was investigated by evaluating the signal-to-noise ratio (SNR), uniformity, low-contrast detectability, high-contrast spatial resolution, and spatial integrity with the VG-PC gating system. To evaluate the performance of the developed system, we applied the VG-PC gating system to a total of seven patients; six patients received stereotactic ablative radiotherapy (SABR) and one patient received conventional fractionated radiation therapy. The projected cine MR images were visible even when the room light was on. No image data loss or additional time delay during delivery of image data were observed. Every indicator representing MRI quality, including SNR, uniformity, low-contrast detectability, high-contrast spatial resolution, and spatial integrity exhibited values higher than the tolerance levels of the manufacturer with the VG-PC gating system; therefore, the presence of the VG-PC gating system in the treatment room did not degrade the MR image quality. The average beam-off times due to respiratory gating with and without the VG-PC gating system were 830.3 ± 278.2 s and 1264.2 ± 302.1 s respectively (P = 0.005). Consequently, the total treatment times excluding

  5. Multicentre evaluation of targeted and systematic biopsies using magnetic resonance and ultrasound image-fusion guided transperineal prostate biopsy in patients with a previous negative biopsy.

    Science.gov (United States)

    Hansen, Nienke L; Kesch, Claudia; Barrett, Tristan; Koo, Brendan; Radtke, Jan P; Bonekamp, David; Schlemmer, Heinz-Peter; Warren, Anne Y; Wieczorek, Kathrin; Hohenfellner, Markus; Kastner, Christof; Hadaschik, Boris

    2017-11-01

    To evaluate the detection rates of targeted and systematic biopsies in magnetic resonance imaging (MRI) and ultrasound (US) image-fusion transperineal prostate biopsy for patients with previous benign transrectal biopsies in two high-volume centres. A two centre prospective outcome study of 487 patients with previous benign biopsies that underwent transperineal MRI/US fusion-guided targeted and systematic saturation biopsy from 2012 to 2015. Multiparametric MRI (mpMRI) was reported according to Prostate Imaging Reporting and Data System (PI-RADS) Version 1. Detection of Gleason score 7-10 prostate cancer on biopsy was the primary outcome. Positive (PPV) and negative (NPV) predictive values including 95% confidence intervals (95% CIs) were calculated. Detection rates of targeted and systematic biopsies were compared using McNemar's test. The median (interquartile range) PSA level was 9.0 (6.7-13.4) ng/mL. PI-RADS 3-5 mpMRI lesions were reported in 343 (70%) patients and Gleason score 7-10 prostate cancer was detected in 149 (31%). The PPV (95% CI) for detecting Gleason score 7-10 prostate cancer was 0.20 (±0.07) for PI-RADS 3, 0.32 (±0.09) for PI-RADS 4, and 0.70 (±0.08) for PI-RADS 5. The NPV (95% CI) of PI-RADS 1-2 was 0.92 (±0.04) for Gleason score 7-10 and 0.99 (±0.02) for Gleason score ≥4 + 3 cancer. Systematic biopsies alone found 125/138 (91%) Gleason score 7-10 cancers. In patients with suspicious lesions (PI-RADS 4-5) on mpMRI, systematic biopsies would not have detected 12/113 significant prostate cancers (11%), while targeted biopsies alone would have failed to diagnose 10/113 (9%). In equivocal lesions (PI-RADS 3), targeted biopsy alone would not have diagnosed 14/25 (56%) of Gleason score 7-10 cancers, whereas systematic biopsies alone would have missed 1/25 (4%). Combination with PSA density improved the area under the curve of PI-RADS from 0.822 to 0.846. In patients with high probability mpMRI lesions, the highest detection rates of Gleason

  6. Comparison of continuous vs. pulsed focused ultrasound in treated muscle tissue as evaluated by magnetic resonance imaging, histological analysis, and microarray analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hundt, Walter [Stanford University School of Medicine, Lucas MRS Research Center, Department of Radiology, Stanford, CA (United States); Ludwig Maximilians University of Munich, Department of Radiology, Munich (Germany); Yuh, Esther L.; Bednarski, Mark D.; Guccione, Samira [Stanford University School of Medicine, Lucas MRS Research Center, Department of Radiology, Stanford, CA (United States); Steinbach, Silke [Technical University of Munich, Department of Otolaryngology Head and Neck Surgery, Munich (Germany)

    2008-05-15

    The purpose of this study was to investigate the effect of different application modes of high intensity focused ultrasound (HIFU) to muscle tissue. HIFU was applied to muscle tissue of the flank in C3H/Km mice. Two dose regimes were investigated, a continuous HIFU and a short-pulsed HIFU mode. Three hours after HIFU treatment pre- and post-contrast T1-weighted, T2-weighted images and a diffusion-weighted STEAM sequence were obtained. After MR imaging, the animals were euthenized and the treated, and the non-treated tissue was taken out for histology and functional genomic analysis. T2 images showed increased signal intensity and post-contrast T1 showed a decreased contrast uptake in the central parts throughout the tissue of both HIFU modes. A significantly higher diffusion coefficient was found in the muscle tissue treated with continuous wave focused ultrasound. Gene expression analysis revealed profound changes of 54 genes. For most of the analyzed genes higher expression was found after treatment with the short-pulse mode. The highest up-regulated genes encoded for the MHC class III (FC {approx}84), HSP 70 (FC {approx}75) and FBJ osteosarcoma related oncogene (FC {approx}21). Immunohistology and the immunoblot analysis confirmed the presence of HSP70 protein in both applied HIFU modes. The use of HIFU treatment on muscle tissue results in dramatic changes in gene expression; however, the same genes are up-regulated after the application of continuous or pulsed HIFU, indicating that the tissue reaction is independent of the type of tissue damage. (orig.)

  7. Intraprocedure contrast enhanced ultrasound: the value in assessing the effect of ultrasound-guided high intensity focused ultrasound ablation for uterine fibroids.

    Science.gov (United States)

    Peng, Song; Hu, Liang; Chen, Wenzhi; Chen, Jinyun; Yang, Caiyong; Wang, Xi; Zhang, Rong; Wang, Zhibiao; Zhang, Lian

    2015-04-01

    To investigate the value of microbubble contrast-enhanced ultrasound (CEUS) in evaluating the treatment response of uterine fibroids to HIFU ablation. Sixty-eight patients with a solitary uterine fibroid from the First Affiliated Hospital of Chongqing Medical University were included and analyzed. All patients underwent pre- and post-treatment magnetic resonance imaging (MRI) with a standardized protocol, as well as pre-evaluation, intraprocedure, and immediate post-treatment CEUS. CEUS and MRI were compared by different radiologists. In comparison with MRI, CEUS showed that the size of fibroids, volume of fibroids, size of non-perfused regions, non-perfused volume (NPV) or fractional ablation (NPV ratio) was similar to that of MRI. In terms of CEUS examination results, the median volume of fibroids was 75.2 (interquartile range, 34.2-127.3) cm(3), the median non-perfused volume was 54.9 (interquartile range, 28.0-98.1) cm(3), the mean fractional ablation was 83.7±13.6 (range, 30.0-100.0)%. In terms of MRI examination results, the median volume of fibroids was 74.1 (interquartile range, 33.4-116.2) cm(3). On the basis of contrast-enhanced T1-weighted images immediately after HIFU treatment, the median non-perfused volume was 58.5 (interquartile range, 27.7-100.0) cm(3), the average fractional ablation was 84.2±14.2 (range, 40.0-100.0)%. CEUS clearly showed the size of fibroids and the non-perfused areas of the fibroid. Results from CEUS correlated well with results obtained from MRI. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Enhanced therapeutic agent delivery through magnetic resonance imaging-monitored focused ultrasound blood-brain barrier disruption for brain tumor treatment: an overview of the current preclinical status.

    Science.gov (United States)

    Liu, Hao-Li; Yang, Hung-Wei; Hua, Mu-Yi; Wei, Kuo-Chen

    2012-01-01

    Malignant glioma is a severe primary CNS cancer with a high recurrence and mortality rate. The current strategy of surgical debulking combined with radiation therapy or chemotherapy does not provide good prognosis, tumor progression control, or improved patient survival. The blood-brain barrier (BBB) acts as a major obstacle to chemotherapeutic treatment of brain tumors by severely restricting drug delivery into the brain. Because of their high toxicity, chemotherapeutic drugs cannot be administered at sufficient concentrations by conventional delivery methods to significantly improve long-term survival of patients with brain tumors. Temporal disruption of the BBB by microbubble-enhanced focused ultrasound (FUS) exposure can increase CNS-blood permeability, providing a promising new direction to increase the concentration of therapeutic agents in the brain tumor and improve disease control. Under the guidance and monitoring of MR imaging, a brain drug-delivery platform can be developed to control and monitor therapeutic agent distribution and kinetics. The success of FUS BBB disruption in delivering a variety of therapeutic molecules into brain tumors has recently been demonstrated in an animal model. In this paper the authors review a number of critical studies that have demonstrated successful outcomes, including enhancement of the delivery of traditional clinically used chemotherapeutic agents or application of novel nanocarrier designs for actively transporting drugs or extending drug half-lives to significantly improve treatment efficacy in preclinical animal models.

  9. Feedback control of temperature evolution in rabbit kidney in vivo using MRI guided focused ultrasound. Application to renal VX2 carcinoma ablation

    Science.gov (United States)

    Delemazure, A. S.; Salomir, R.; Grenier, N.; Palussière, J.; Deminière, C.; Mougenot, C.; Moonen, C. W.

    2005-03-01

    A significant number of patients with small renal tumours may get benefit from in situ thermo-ablation techniques. Focused ultrasound is a non-invasive approach which offers excellent flexibility. On the other hand, real time MR thermometry is a valuable tool for monitoring and controlling therapy. In this study, coupling of focused ultrasound with PRF-based, respiratory-gated MR thermometry was used to provide temperature feedback control for local hyperthermia in the rabbit kidney. Two heating protocols were initially used in healthy kidneys (medulla and cortex): 1. fixed focal point heating; 2. spiral trajectories of the focal point. Further, five VX2 renal carcinomas were treated with multiple focal point heating in each tumour. Post-treatment MRI follow up and post mortem histology were performed. The shape and size of the lesions (MRI, histology) were compared to the calculated thermal dose map. The standard deviation of the MR thermometry ranged from 0.5°C to 1°C. The temperature controller matched the objective curve with approximately 1°C precision (fixed focal point mode). Several technical and physiological difficulties for spiral heating could not be overcome with the available setup. Thermal ablation with temperature feedback control in healthy and tumour bearing kidney was demonstrated to be feasible and effective, despite specific challenges (deep seated organ, respiratory motion, high blood perfusion).

  10. Percutaneous Image-Guided Screw Fixation of Bone Lesions in Cancer Patients: Double-Centre Analysis of Outcomes including Local Evolution of the Treated Focus

    Energy Technology Data Exchange (ETDEWEB)

    Cazzato, Roberto Luigi, E-mail: gigicazzato@hotmail.it; Koch, Guillaume, E-mail: guillaume.koch@chru-strasbourg.fr [Hôpitaux Universitaires de Strasbourg, HUS, Department of Interventional Radiology, Nouvel Hôpital Civil (France); Buy, Xavier, E-mail: x.buy@bordeaux.unicancer.fr [Institut Bergonié, Department of Radiology (France); Ramamurthy, Nitin, E-mail: nitin-ramamurthy@hotmail.com [Norfolk and Norwich University Hospital, Department of Radiology (United Kingdom); Tsoumakidou, Georgia, E-mail: georgia.tsoumakidou@chru-strasbourg.fr; Caudrelier, Jean, E-mail: jean.caudrelier@chru-strasbourg.fr [Hôpitaux Universitaires de Strasbourg, HUS, Department of Interventional Radiology, Nouvel Hôpital Civil (France); Catena, Vittorio, E-mail: v.catena@bordeaux.unicancer.fr [Institut Bergonié, Department of Radiology (France); Garnon, Julien, E-mail: juleiengarnon@gmail.com [Hôpitaux Universitaires de Strasbourg, HUS, Department of Interventional Radiology, Nouvel Hôpital Civil (France); Palussiere, Jean, E-mail: j.palussiere@bordeaux.unicancer.fr [Institut Bergonié, Department of Radiology (France); Gangi, Afshin, E-mail: gangi@unistra.fr [Hôpitaux Universitaires de Strasbourg, HUS, Department of Interventional Radiology, Nouvel Hôpital Civil (France)

    2016-10-15

    AimTo review outcomes and local evolution of treated lesions following percutaneous image-guided screw fixation (PIGSF) of pathological/insufficiency fractures (PF/InF) and impeding fractures (ImF) in cancer patients at two tertiary centres.Materials and methodsThirty-two consecutive patients (mean age 67.5 years; range 33–86 years) with a range of tumours and prognoses underwent PIGSF for non/minimally displaced PF/InF and ImF. Screws were placed under CT/fluoroscopy or cone-beam CT guidance, with or without cementoplasty. Clinical outcomes were assessed using a simple 4-point scale (1 = worse; 2 = stable; 3 = improved; 4 = significantly improved). Local evolution was reviewed on most recent follow-up imaging. Technical success, complications, and overall survival were evaluated.ResultsThirty-six lesions were treated with 74 screws mainly in the pelvis and femoral neck (58.2 %); including 47.2 % PF, 13.9 % InF, and 38.9 % ImF. Cementoplasty was performed in 63.9 % of the cases. Technical success was 91.6 %. Hospital stay was ≤3 days; 87.1 % of lesions were improved at 1-month follow-up; three major complications (early screw-impingement radiculopathy; accelerated coxarthrosis; late coxofemoral septic arthritis) and one minor complication were observed. Unfavourable local evolution at imaging occurred in 3/24 lesions (12.5 %) at mean 8.7-month follow-up, including poor consolidation (one case) and screw loosening (two cases, at least 1 symptomatic). There were no cases of secondary fractures.ConclusionsPIGSF is feasible for a wide range of oncologic patients, offering good short-term efficacy, acceptable complication rates, and rapid recovery. Unfavourable local evolution at imaging may be relatively frequent, and requires close clinico-radiological surveillance.

  11. Basic study on ultrasonic monitoring using 1.5-dimensional ultrasound phased array for ultrasound-guided high-intensity focused ultrasound treatment

    Science.gov (United States)

    Takagi, Ryo; Iwasaki, Ryosuke; Tomiyasu, Kentaro; Yoshizawa, Shin; Umemura, Shin-ichiro

    2017-07-01

    We have been studying a real-time detection method for tissue changes induced by high-intensity focused ultrasound (HIFU) treatment using ultrasonic RF signals. It has been difficult to track the target region when the tissue to be treated deviates from the imaging plane along the elevation axis of the probe. In this study, a new 1.5-dimensional (1.5D) prototype phased array probe consisting of transducer elements along both the lateral and elevation axes was developed to track tissue motion along the elevation axis of the probe, and the elevational displacement range where the tracking is effective was investigated. The complex cross-correlation coefficient based on a block matching algorithm was applied to 2.5D volumetric RF images acquired by the 1.5D probe and the displacement vector along the elevation axis was calculated. From the results, it was found that the effective tracking range using this prototype probe was up to 3 mm, about 3 times that of a conventional 1D imaging probe. The proposed 1.5D phased array probe has the potential to track target tissue with intrafractional motion.

  12. Focused ultrasound for treatment of bone tumours.

    Science.gov (United States)

    Rodrigues, Dario B; Stauffer, Paul R; Vrba, David; Hurwitz, Mark D

    2015-05-01

    Focused ultrasound (FUS) is a modality with rapidly expanding applications across the field of medicine. Treatment of bone lesions with FUS including both benign and malignant tumours has been an active area of investigation. Recently, as a result of a successful phase III trial, magnetic resonance-guided FUS is now a standardised option for treatment of painful bone metastases. This report reviews the clinical applications amenable to treatment with FUS and provides background on FUS and image guidance techniques, results of clinical studies, and future directions. A comprehensive literature search and review of abstracts presented at the recently completed fourth International Focused Ultrasound Symposium was performed. Case reports and older publications revisited in more recent studies were excluded. For clinical studies that extend beyond bone tumours, only the data regarding bone tumours are presented. Fifteen studies assessing the use of focused ultrasound in treatment of primary benign bone tumours, primary malignant tumours, and metastatic tumours meeting the search criteria were identified. For these clinical studies the responders group varied within 91-100%, 85-87% and 64-94%, respectively. Major complications were reported in the ranges 0%, 0-28% and 0-4% for primary benign, malignant and metastatic tumours, respectively. Image-guided FUS is both safe and effective in the treatment of primary and secondary tumours. Additional phase III trials are warranted to more fully define the role of FUS in treatment of both benign and malignant bone tumours.

  13. Resonant power converters

    CERN Document Server

    Kazimierczuk, Marian K

    2012-01-01

    This book is devoted to resonant energy conversion in power electronics. It is a practical, systematic guide to the analysis and design of various dc-dc resonant inverters, high-frequency rectifiers, and dc-dc resonant converters that are building blocks of many of today's high-frequency energy processors. Designed to function as both a superior senior-to-graduate level textbook for electrical engineering courses and a valuable professional reference for practicing engineers, it provides students and engineers with a solid grasp of existing high-frequency technology, while acquainting them wit

  14. Focus group discussions

    CERN Document Server

    Hennink, Monique M

    2014-01-01

    The Understanding Research series focuses on the process of writing up social research. The series is broken down into three categories: Understanding Statistics, Understanding Measurement, and Understanding Qualitative Research. The books provide researchers with guides to understanding, writing, and evaluating social research. Each volume demonstrates how research should be represented, including how to write up the methodology as well as the research findings. Each volume also reviews how to appropriately evaluate published research. Focus Group Discussions addresses the challenges associated with conducting and writing focus group research. It provides detailed guidance on the practical and theoretical considerations in conducting focus group discussions including: designing the discussion guide, recruiting participants, training a field team, moderating techniques and ethical considerations. Monique Hennink describes how a methodology section is read and evaluated by others, such as journal reviewers or ...

  15. Evaluation of different magnetic resonance imaging contrast materials to be used as dummy markers in image-guided brachytherapy for gynecologic malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Sales, Camila Pessoa; Carvalho, Heloisa de Andrade; Rubo, Rodrigo Augusto; Stuart, Silvia Radwanski; Rodrigues, Laura Natal, E-mail: camyps@gmail.com [Universidade de Sao Paulo (InRad/HC/FM/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Instituto de Radiologia; Taverna, Khallil Chaim; Pastorello, Bruno Fraccini [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Departamento de Radiologia e Oncologia. Lab. de Ressonancia Magnetica em Neurorradiologia; Borgonovi, Arthur Felipe [Royal Philips Electronics, Eindhoven (Netherlands)

    2016-05-15

    Objective: to identify a contrast material that could be used as a dummy marker for magnetic resonance imaging. Materials and methods: magnetic resonance images were acquired with six different catheter-filling materials - water, glucose 50%, saline, olive oil, glycerin, and copper sulfate (CuSO{sub 4}) water solution (2.08 g/L) - inserted into compatible computed tomography/magnetic resonance imaging ring applicators placed in a phantom made of gelatin and CuSO{sub 4}. The best contrast media were tested in four patients with the applicators in place. Results: in T2-weighted sequences, the best contrast was achieved with the CuSO{sub 4}-filled catheters, followed by saline- and glycerin-filled catheters, which presented poor visualization. In addition (also in T2-weighted sequences), CuSO{sub 4} presented better contrast when tested in the phantom than when tested in the patients, in which it provided some contrast but with poor identification of the first dwell position, mainly in the ring. Conclusion: we found CuSO{sub 4} to be the best solution for visualization of the applicator channels, mainly in T2-weighted images in vitro, although the materials tested presented low signal intensity in the images obtained in vivo, as well as poor precision in determining the first dwell position. (author)

  16. Evaluation of different magnetic resonance imaging contrast materials to be used as dummy markers in image-guided brachytherapy for gynecologic malignancies

    Directory of Open Access Journals (Sweden)

    Camila Pessoa Sales

    2016-06-01

    Full Text Available Abstract Objective: To identify a contrast material that could be used as a dummy marker for magnetic resonance imaging. Materials and Methods: Magnetic resonance images were acquired with six different catheter-filling materials-water, glucose 50%, saline, olive oil, glycerin, and copper sulfate (CuSO4 water solution (2.08 g/L-inserted into compatible computed tomography/magnetic resonance imaging ring applicators placed in a phantom made of gelatin and CuSO4. The best contrast media were tested in four patients with the applicators in place. Results: In T2-weighted sequences, the best contrast was achieved with the CuSO4-filled catheters, followed by saline- and glycerin-filled catheters, which presented poor visualization. In addition (also in T2-weighted sequences, CuSO4 presented better contrast when tested in the phantom than when tested in the patients, in which it provided some contrast but with poor identification of the first dwell position, mainly in the ring. Conclusion: We found CuSO4 to be the best solution for visualization of the applicator channels, mainly in T2-weighted images in vitro, although the materials tested presented low signal intensity in the images obtained in vivo, as well as poor precision in determining the first dwell position.

  17. Evaluation of different magnetic resonance imaging contrast materials to be used as dummy markers in image-guided brachytherapy for gynecologic malignancies*

    Science.gov (United States)

    Sales, Camila Pessoa; Carvalho, Heloisa de Andrade; Taverna, Khallil Chaim; Pastorello, Bruno Fraccini; Rubo, Rodrigo Augusto; Borgonovi, Arthur Felipe; Stuart, Silvia Radwanski; Rodrigues, Laura Natal

    2016-01-01

    Objective To identify a contrast material that could be used as a dummy marker for magnetic resonance imaging. Materials and Methods Magnetic resonance images were acquired with six different catheter-filling materials-water, glucose 50%, saline, olive oil, glycerin, and copper sulfate (CuSO4) water solution (2.08 g/L)-inserted into compatible computed tomography/magnetic resonance imaging ring applicators placed in a phantom made of gelatin and CuSO4. The best contrast media were tested in four patients with the applicators in place. Results In T2-weighted sequences, the best contrast was achieved with the CuSO4-filled catheters, followed by saline- and glycerin-filled catheters, which presented poor visualization. In addition (also in T2-weighted sequences), CuSO4 presented better contrast when tested in the phantom than when tested in the patients, in which it provided some contrast but with poor identification of the first dwell position, mainly in the ring. Conclusion We found CuSO4 to be the best solution for visualization of the applicator channels, mainly in T2-weighted images in vitro, although the materials tested presented low signal intensity in the images obtained in vivo, as well as poor precision in determining the first dwell position. PMID:27403016

  18. Identification of Threshold Prostate Specific Antigen Levels to Optimize the Detection of Clinically Significant Prostate Cancer by Magnetic Resonance Imaging/Ultrasound Fusion Guided Biopsy

    Science.gov (United States)

    Shakir, Nabeel A.; George, Arvin K.; Siddiqui, M. Minhaj; Rothwax, Jason T.; Rais-Bahrami, Soroush; Stamatakis, Lambros; Su, Daniel; Okoro, Chinonyerem; Raskolnikov, Dima; Walton-Diaz, Annerleim; Simon, Richard; Turkbey, Baris; Choyke, Peter L.; Merino, Maria J.; Wood, Bradford J.; Pinto, Peter A.

    2015-01-01

    Purpose Prostate specific antigen sensitivity increases with lower threshold values but with a corresponding decrease in specificity. Magnetic resonance imaging/ultrasound targeted biopsy detects prostate cancer more efficiently and of higher grade than standard 12-core transrectal ultrasound biopsy but the optimal population for its use is not well defined. We evaluated the performance of magnetic resonance imaging/ultrasound targeted biopsy vs 12-core biopsy across a prostate specific antigen continuum. Materials and Methods We reviewed the records of all patients enrolled in a prospective trial who underwent 12-core transrectal ultrasound and magnetic resonance imaging/ultrasound targeted biopsies from August 2007 through February 2014. Patients were stratified by each of 4 prostate specific antigen cutoffs. The greatest Gleason score using either biopsy method was compared in and across groups as well as across the population prostate specific antigen range. Clinically significant prostate cancer was defined as Gleason 7 (4 + 3) or greater. Univariate and multivariate analyses were performed. Results A total of 1,003 targeted and 12-core transrectal ultrasound biopsies were performed, of which 564 diagnosed prostate cancer for a 56.2% detection rate. Targeted biopsy led to significantly more upgrading to clinically significant disease compared to 12-core biopsy. This trend increased more with increasing prostate specific antigen, specifically in patients with prostate specific antigen 4 to 10 and greater than 10 ng/ml. Prostate specific antigen 5.2 ng/ml or greater captured 90% of upgrading by targeted biopsy, corresponding to 64% of patients who underwent multiparametric magnetic resonance imaging and subsequent fusion biopsy. Conversely a greater proportion of clinically insignificant disease was detected by 12-core vs targeted biopsy overall. These differences persisted when controlling for potential confounders on multivariate analysis. Conclusions Prostate

  19. Prostate-specific Antigen Parameters and Prostate Health Index Enhance Prostate Cancer Prediction With the In-bore 3-T Magnetic Resonance Imaging-guided Transrectal Targeted Prostate Biopsy After Negative 12-Core Biopsy.

    Science.gov (United States)

    Friedl, Alexander; Stangl, Kathrin; Bauer, Wilhelm; Kivaranovic, Danijel; Schneeweiss, Jenifer; Susani, Martin; Hruby, Stephan; Lusuardi, Lukas; Lomoschitz, Fritz; Eisenhuber-Stadler, Edith; Schima, Wolfgang; Brössner, Clemens

    2017-12-01

    To assess prostate cancer (PCa) detection and prediction by combining the in-bore magnetic resonance imaging-guided transrectal targeted prostate biopsy (MRGB) with prostate-specific antigen (PSA) parameters and the Prostate Health Index (PHI) in case of negative 12-core standard biopsy. A total of 112 men (2014-2016) underwent 3-T multiparametric magnetic resonance imaging and subsequent MRGB of Prostate Imaging-Reporting and Data System (PI-RADS) lesions 3-5. Ancillary PSA parameters (PSA ratio [%fPSA] and PSA density [PSAD]) and the PHI and PHI density (PHID) were recorded. With these parameters in combination with MRGB, PCa prediction was calculated. The most common lesions biopsied were PI-RADS 4 (66%), located in the peripheral zone (64%), in the middle (58%) and anterior (65%) sections of the prostate, and 13 mm (IQR 10-15) in size. PCa was found in 62 (55%) patients (28% Gleason score ≥7). PSAD (0.15 vs 0.21; P = .0051), %fPSA (16 vs 13; P = .0191), PHI (45 vs 69; P PI-RADS 3-5 lesions. By considering PHI and PHID, 82% and 62% of unnecessary biopsies could have been avoided, failing to detect 31% and 16% of cancers. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Comparison of the Stereotactic Accuracies of Function-Guided Deep Brain Stimulation, Calculated Using Multitrack Target Locations Geometrically Inferred from Three-Dimensional Trajectory Rotations, and of Magnetic Resonance Imaging-Guided Deep Brain Stimulation and Outcomes.

    Science.gov (United States)

    Park, Seong-Cheol; Lee, Chong Sik; Kim, Seok Min; Choi, Eu Jene; Lee, Jung Kyo

    2017-02-01

    In previous studies, multitrack trajectories in deep brain stimulation (DBS) have usually been approximated. Using a geometrically more accurate method, we compared the stereotactic accuracy of DBS with multitrack microelectrode recording and awake stimulation (function group) and MRI-guided DBS (MRI group). One hundred and seventy-two leads used in DBS between April 2014 and January 2016 were evaluated for stereotactic errors. Targets were the subthalamic nucleus (STN, 139 leads) or globus pallidus interna (GPi, 33 leads). We geometrically calculated shifted-track targets by considering the three-dimensional stereotactic ring and arc rotations. Stereotactic errors were calculated using Euclidean distances perpendicular to trajectories. Motor outcomes according to the Unified Parkinson's Disease Rating Scale (UPDRS) part III, improvement percentages by stimulations, were analyzed in 24 patients with 1 year follow-ups. Functional evaluation tended to increase stereotactic errors in the STN function group (n = 129; 1.4 ± 0.7 mm) more than in the STN MRI group (n = 10; 1.0 ± 0.6 mm; P = 0.06). Leads with higher stereotactic errors (n = 65; 1.6 ± 0.7 mm; P 2.5 mm tended to relate to a worse outcome (P = 0.087). Stereotactic errors were lower (n = 33; 0.9 ± 0.5 mm) in the GPi MRI group. Multitrack DBS using intraoperative functional evaluation resulted in worse stereotactic accuracy than did MRI-guided DBS. However, track shifts in function-guided DBS can approach MRI targets effectively. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Imaging of female infertility: a pictorial guide to the hysterosalpingography, ultrasonography, and magnetic resonance imaging findings of the congenital and acquired causes of female infertility.

    Science.gov (United States)

    Kaproth-Joslin, Katherine; Dogra, Vikram

    2013-11-01

    Hysterosalpingography is the gold standard in assessing the patency of the fallopian tubes, which is among the most common causes of female factor infertility, making this technique the most frequent first-choice imaging modality in the assessment of female infertility. Ultrasonography and magnetic resonance imaging are typically used for evaluation of indeterminate or complicated cases of female infertility and presurgical planning. Imaging also plays a role in the detection of the secondary causes of ovarian factor infertility, including endometriosis and polycystic ovarian syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Surgical neuro navigator guided by preoperative magnetic resonance images, based on a magnetic position sensor;Neuronavegador cirurgico guiado por imagens de ressonancia magnetica pre-operatoria, baseado num transdutor de posicao magnetico

    Energy Technology Data Exchange (ETDEWEB)

    Perini, Ana Paula; Siqueira, Rogerio Bulha; Carneiro, Antonio Adilton Oliveira, E-mail: adilton@ffclrp.usp.b [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Filosofia, Ciencias e Letras. Dept. de Fisica e Matematica; Oliveira, Lucas Ferrari de [Universidade Federal de Pelotas (UFPel), RS (Brazil). Dept. de Informatica; Machado, Helio Rubens [Universidade de Sao Paulo (USP), Ribeirao Preto, SP (Brazil). Faculdade de Medicina. Dept. de Neurocirurgia

    2009-08-15

    Image guided neurosurgery enables the neurosurgeon to navigate inside the patient's brain using pre-operative images as a guide and a tracking system, during a