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Sample records for single mri image

  1. Pediatric bowel MRI - accelerated parallel imaging in a single breathhold

    International Nuclear Information System (INIS)

    Hohl, C.; Honnef, D.; Krombach, G.; Muehlenbruch, G.; Guenther, R.W.; Niendorf, T.; Ocklenburg, C.; Wenzl, T.G.

    2008-01-01

    Purpose: to compare highly accelerated parallel MRI of the bowel with conventional balanced FFE sequences in children with inflammatory bowel disease (IBD). Materials and methods: 20 children with suspected or proven IBD underwent MRI using a 1.5 T scanner after oral administration of 700-1000 ml of a Mannitol solution and an additional enema. The examination started with a 4-channel receiver coil and a conventional balanced FFE sequence in axial (2.5 s/slice) and coronal (4.7 s/slice) planes. Afterwards highly accelerated (R = 5) balanced FFE sequences in axial (0.5 s/slice) and coronal (0.9 s/slice) were performed using a 32-channel receiver coil and parallel imaging (SENSE). Both receiver coils achieved a resolution of 0.88 x 0.88 mm with a slice thickness of 5 mm (coronal) and 6 mm (axial) respectively. Using the conventional imaging technique, 4 - 8 breathholds were needed to cover the whole abdomen, while parallel imaging shortened the acquisition time down to a single breathhold. Two blinded radiologists did a consensus reading of the images regarding pathological findings, image quality, susceptibility to artifacts and bowel distension. The results for both coil systems were compared using the kappa-(κ)-coefficient, differences in the susceptibility to artifacts were checked with the Wilcoxon signed rank test. Statistical significance was assumed for p = 0.05. Results: 13 of the 20 children had inflammatory bowel wall changes at the time of the examination, which could be correctly diagnosed with both coil systems in 12 of 13 cases (92%). The comparison of both coil systems showed a good agreement for pathological findings (κ = 0.74 - 1.0) and the image quality. Using parallel imaging significantly more artifacts could be observed (κ = 0.47)

  2. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...

  3. Single-shot spiral imaging enabled by an expanded encoding model: Demonstration in diffusion MRI.

    Science.gov (United States)

    Wilm, Bertram J; Barmet, Christoph; Gross, Simon; Kasper, Lars; Vannesjo, S Johanna; Haeberlin, Max; Dietrich, Benjamin E; Brunner, David O; Schmid, Thomas; Pruessmann, Klaas P

    2017-01-01

    The purpose of this work was to improve the quality of single-shot spiral MRI and demonstrate its application for diffusion-weighted imaging. Image formation is based on an expanded encoding model that accounts for dynamic magnetic fields up to third order in space, nonuniform static B 0 , and coil sensitivity encoding. The encoding model is determined by B 0 mapping, sensitivity mapping, and concurrent field monitoring. Reconstruction is performed by iterative inversion of the expanded signal equations. Diffusion-tensor imaging with single-shot spiral readouts is performed in a phantom and in vivo, using a clinical 3T instrument. Image quality is assessed in terms of artefact levels, image congruence, and the influence of the different encoding factors. Using the full encoding model, diffusion-weighted single-shot spiral imaging of high quality is accomplished both in vitro and in vivo. Accounting for actual field dynamics, including higher orders, is found to be critical to suppress blurring, aliasing, and distortion. Enhanced image congruence permitted data fusion and diffusion tensor analysis without coregistration. Use of an expanded signal model largely overcomes the traditional vulnerability of spiral imaging with long readouts. It renders single-shot spirals competitive with echo-planar readouts and thus deploys shorter echo times and superior readout efficiency for diffusion imaging and further prospective applications. Magn Reson Med 77:83-91, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  4. Ultrafast bold fMRI using single-shot spin-echo echo planar imaging

    Directory of Open Access Journals (Sweden)

    Boujraf Said

    2009-01-01

    Full Text Available The choice of imaging parameters for functional MRI can have an impact on the accuracy of functional localization by affecting the image quality and the degree of blood oxygenation-dependent (BOLD contrast achieved. By improving sampling efficiency, parallel acquisition techniques such as sensitivity encoding (SENSE have been used to shorten readout trains in single-shot (SS echo planar imaging (EPI. This has been applied to susceptibility artifact reduction and improving spatial resolution. SENSE together with single-shot spin-echo (SS-SE imaging may also reduce off-resonance artifacts. The goal of this work was to investigate the BOLD response of a SENSE-adapted SE-EPI on a three Tesla scanner. Whole-brain fMRI studies of seven healthy right hand-dominant volunteers were carried out in a three Tesla scanner. fMRI was performed using an SS-SE EPI sequence with SENSE. The data was processed using statistical parametric mapping. Both, group and individual subject data analyses were performed. Individual average percentage and maximal percentage signal changes attributed to the BOLD effect in M1 were calculated for all the subjects as a function of echo time. Corresponding activation maps and the sizes of the activated clusters were also calculated. Our results show that susceptibility artifacts were reduced with the use of SENSE; and the acquired BOLD images were free of the typical quadrature artifacts of SS-EPI. Such measures are crucial at high field strengths. SS SE-EPI with SENSE offers further benefits in this regard and is more specific for oxygenation changes in the microvasculature bed. Functional brain activity can be investigated with the help of single-shot spin echo EPI using SENSE at high magnetic fields.

  5. All-in-one interictal presurgical imaging in patients with epilepsy: single-session EEG/PET/(f)MRI

    Energy Technology Data Exchange (ETDEWEB)

    Grouiller, Frederic; Delattre, Benedicte M.A.; Lazeyras, Francois; Ratib, Osman; Vargas, Maria I.; Garibotto, Valentina [Geneva University Hospital, Department of Radiology and Medical Informatics, Geneva 14 (Switzerland); Pittau, Francesca; Spinelli, Laurent; Seeck, Margitta; Vulliemoz, Serge [Geneva University Hospital, EEG and Epilepsy Unit, Department of Neurology, Geneva 14 (Switzerland); Heinzer, Susanne [Philips AG Healthcare, Zuerich (Switzerland); Iannotti, Giannina R. [Geneva University Hospital, Functional Brain Mapping Laboratory, Department of Fundamental Neurosciences, Geneva 14 (Switzerland)

    2015-04-17

    In patients with pharmacoresistant focal epilepsy, resection of the epileptic focus can lead to freedom from seizures or significant improvement in well-selected candidates. Localization of the epileptic focus with multimodal concordance is crucial for a good postoperative outcome. Beyond the detection of epileptogenic lesions on structural MRI and focal hypometabolism on FDG PET, EEG-based Electric Source Imaging (ESI) and simultaneous EEG and functional MRI (EEG-fMRI) are increasingly applied for mapping epileptic activity. We here report presurgical multimodal interictal imaging using a hybrid PET/MR scanner for single-session FDG PET, MRI, EEG-fMRI and ESI. This quadrimodal imaging procedure was performed in a single session in 12 patients using a high-density (256 electrodes) MR-compatible EEG system and a hybrid PET/MR scanner. EEG was used to exclude subclinical seizures during uptake of the PET tracer, to compute ESI on interictal epileptiform discharges and to guide fMRI analysis for mapping haemodynamic changes correlated with interictal epileptiform activity. The whole multimodal recording was performed in less than 2 hours with good patient comfort and data quality. Clinically contributory examinations with at least two modalities were obtained in nine patients and with all modalities in five patients. This single-session quadrimodal imaging procedure provided reliable and contributory interictal clinical data. This procedure avoids multiple scanning sessions and is associated with less radiation exposure than PET-CT. Moreover, it guarantees the same medication level and medical condition for all modalities. The procedure improves workflow and could reduce the duration and cost of presurgical epilepsy evaluations. (orig.)

  6. All-in-one interictal presurgical imaging in patients with epilepsy: single-session EEG/PET/(f)MRI

    International Nuclear Information System (INIS)

    Grouiller, Frederic; Delattre, Benedicte M.A.; Lazeyras, Francois; Ratib, Osman; Vargas, Maria I.; Garibotto, Valentina; Pittau, Francesca; Spinelli, Laurent; Seeck, Margitta; Vulliemoz, Serge; Heinzer, Susanne; Iannotti, Giannina R.

    2015-01-01

    In patients with pharmacoresistant focal epilepsy, resection of the epileptic focus can lead to freedom from seizures or significant improvement in well-selected candidates. Localization of the epileptic focus with multimodal concordance is crucial for a good postoperative outcome. Beyond the detection of epileptogenic lesions on structural MRI and focal hypometabolism on FDG PET, EEG-based Electric Source Imaging (ESI) and simultaneous EEG and functional MRI (EEG-fMRI) are increasingly applied for mapping epileptic activity. We here report presurgical multimodal interictal imaging using a hybrid PET/MR scanner for single-session FDG PET, MRI, EEG-fMRI and ESI. This quadrimodal imaging procedure was performed in a single session in 12 patients using a high-density (256 electrodes) MR-compatible EEG system and a hybrid PET/MR scanner. EEG was used to exclude subclinical seizures during uptake of the PET tracer, to compute ESI on interictal epileptiform discharges and to guide fMRI analysis for mapping haemodynamic changes correlated with interictal epileptiform activity. The whole multimodal recording was performed in less than 2 hours with good patient comfort and data quality. Clinically contributory examinations with at least two modalities were obtained in nine patients and with all modalities in five patients. This single-session quadrimodal imaging procedure provided reliable and contributory interictal clinical data. This procedure avoids multiple scanning sessions and is associated with less radiation exposure than PET-CT. Moreover, it guarantees the same medication level and medical condition for all modalities. The procedure improves workflow and could reduce the duration and cost of presurgical epilepsy evaluations. (orig.)

  7. Magnetic Resonance Imaging (MRI) Safety

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a powerful ... the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that ...

  10. Clinical utility of simultaneous whole-body 18F-FDG PET/MRI as a single-step imaging modality in the staging of primary nasopharyngeal carcinoma.

    Science.gov (United States)

    Chan, Sheng-Chieh; Yeh, Chih-Hua; Yen, Tzu-Chen; Ng, Shu-Hang; Chang, Joseph Tung-Chieh; Lin, Chien-Yu; Yen-Ming, Tsang; Fan, Kang-Hsing; Huang, Bing-Shen; Hsu, Cheng-Lung; Chang, Kai-Ping; Wang, Hung-Ming; Liao, Chun-Ta

    2018-03-03

    Both head and neck magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) play a crucial role in the staging of primary nasopharyngeal carcinoma (NPC). In this study, we sought to prospectively investigate the clinical utility of simultaneous whole-body 18F-FDG PET/MRI for primary staging of NPC patients. We examined 113 patients with histologically confirmed NPC who underwent pretreatment, simultaneous whole-body PET/MRI and PET/CT for primary tumor staging. The images obtained with the different imaging modalities were interpreted independently and compared with each other. PET/MRI increased the accuracy of head and neck MRI for assessment of primary tumor extent in four patients via addition of FDG uptake information to increase the conspicuity of morphologically subtle lesions. PET/MR images were more discernible than PET/CT images for mapping tumor extension, especially intracranial invasion. Regarding the N staging assessment, the sensitivity of PET/MRI (99.5%) was higher than that of head and neck MRI (94.2%) and PET/CT (90.9%). PET/MRI was particularly useful for distinguishing retropharyngeal nodal metastasis from adjacent nasopharyngeal tumors. For distant metastasis evaluation, PET/MRI exhibited a similar sensitivity (90% vs. 86.7% vs. 83.3%), but higher positive predictive value (93.1% vs. 78.8% vs. 83.3%) than whole-body MRI and PET/CT, respectively. For tumor staging of NPC, simultaneous whole-body PET/MRI was more accurate than head and neck MRI and PET/CT, and may serve as a single-step staging modality.

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open units are especially helpful for examining larger patients or those with claustrophobia. Newer open MRI units provide very high quality images for ...

  12. MRI: Imaging of stomach

    International Nuclear Information System (INIS)

    Lam, W. W. M; Lee, J. S. W.; Ho, G.

    2007-01-01

    Full text: The study is to determine the optimal MRI bowel preparation regime for visualization of the stomach anatomy, Eight healthy volunteers were asked to take water, 75% barium and blueberry juice. The image quality and tolerance of different stomach distension regime were evaluated. Blueberry juice gave the best distension, but the signal intensity was not very homogeneous. Taking into account the image quality, tolerability and adverse effects, it is concluded that water is the most desirable oral contrast for MR stomach imaging

  13. MRI of hip prostheses using single-point methods : in vitro studies towards the artifact-free imaging of individuals with metal implants

    NARCIS (Netherlands)

    Ramos Cabrer, P.; Duynhoven, van J.P.M.; Toorn, van der A.; Nicolaij, K.

    2004-01-01

    Use of magnetic resonance imaging (MRI) in individuals with orthopedic implants is limited because of the large distortions caused by metallic components. As a possible solution for this problem, we suggest the use of single-point imaging (SPI) methods, which are immune to the susceptibility

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... to a CD or uploaded to a digital cloud server. Currently, MRI is the most sensitive imaging ... over time. top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... claustrophobia. Newer open MRI units provide very high quality images for many types of exams. Older open MRI units may not provide this same image quality. Certain types of exams cannot be performed using ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam is safe for patients with metal implants, except for a few types. ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam is safe for patients with metal implants, except for a ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings ... tomography (CT) scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms that ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... room. In addition to affecting the MRI images, these objects can become projectiles within the MRI scanner ... may cause you and/or others nearby harm. These items include: jewelry, watches, credit cards and hearing ...

  20. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... claustrophobia. Newer open MRI units provide very high quality images for many types of exams. Older open ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... are the limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging ( ... brain) in routine clinical practice. top of page What are some common uses of the procedure? MR ...

  2. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ... MRI an invaluable tool in early diagnosis and evaluation of many conditions, including tumors. MRI enables the ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... used in tattoos may contain iron and could heat up during an MRI scan, but this is ... imaging based on the electrical activity of the heart, such as electrocardiography (EKG). MRI generally is not ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging technique that ... than 30 minutes from the onset of symptoms. Risks The MRI examination poses almost no risk to ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... As the hydrogen atoms return to their usual alignment, they emit different amounts of energy that vary ... story about radiology? Share your patient story here Images × Image Gallery Magnetic Resonance Imaging (MRI) procedure View ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... it is useful to bring that to the attention of the scheduler before the exam and bring ... Image Gallery Magnetic Resonance Imaging (MRI) procedure View full size with caption Pediatric Content Some imaging tests ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. MRI ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... can also provide functional information (fMRI) in selected cases. MR images of the brain and other cranial structures are clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in early diagnosis and evaluation of many conditions, ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... Imaging (MRI) procedure View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... six weeks) before being safe for MRI examinations. Examples include but are not limited to: artificial heart ... the area to be imaged. Furthermore, the examination takes longer than other imaging modalities (typically x-ray ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... Most MRI exams are painless. However, some patients find it uncomfortable to remain still during MR imaging. ... anxious, confused or in severe pain, you may find it difficult to lie still during imaging. A ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... by the interpreting radiologist. Frequently, the differentiation of abnormal (diseased) tissue from normal tissues is better with ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation and ... clearer and more detailed than with other imaging methods. This detail makes MRI an invaluable tool in ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... other imaging methods. This exam does not use ionizing radiation and may require an injection of a contrast ... other internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to ...

  16. Imaging of striatal dopamine transporters in rat brain with single pinhole SPECT and co-aligned MRI is highly reproducible

    International Nuclear Information System (INIS)

    Booij, Jan; Bruin, Kora de; Win, Maartje M.L. de; Lavini, Cristina Mphil; Heeten, Gerard J. den; Habraken, Jan

    2003-01-01

    A recently developed pinhole high-resolution SPECT system was used to measure striatal to non-specific binding ratios in rats (n = 9), after injection of the dopamine transporter ligand 123 I-FP-CIT, and to assess its test/retest reproducibility. For co-alignment purposes, the rat brain was imaged on a 1.5 Tesla clinical MRI scanner using a specially developed surface coil. The SPECT images showed clear striatal uptake. On the MR images, cerebral and extra-cerebral structures could be easily delineated. The mean striatal to non-specific [ 123 I]FP-CIT binding ratios of the test/retest studies were 1.7 ± 0.2 and 1.6 ± 0.2, respectively. The test/retest variability was approximately 9%. We conclude that the assessment of striatal [ 123 I]FP-CIT binding ratios in rats is highly reproducible

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ... Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... fitting and has no metal fasteners. Guidelines about eating and drinking before an MRI exam vary with the specific exam and with the imaging facility. Unless you are told otherwise, you may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the ...

  20. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... absolutely necessary for medical treatment. See the MRI Safety page for more information about pregnancy and MRI. ...

  1. Non-Stationary Rician Noise Estimation in Parallel MRI Using a Single Image: A Variance-Stabilizing Approach.

    Science.gov (United States)

    Pieciak, Tomasz; Aja-Fernandez, Santiago; Vegas-Sanchez-Ferrero, Gonzalo

    2017-10-01

    Parallel magnetic resonance imaging (pMRI) techniques have gained a great importance both in research and clinical communities recently since they considerably accelerate the image acquisition process. However, the image reconstruction algorithms needed to correct the subsampling artifacts affect the nature of noise, i.e., it becomes non-stationary. Some methods have been proposed in the literature dealing with the non-stationary noise in pMRI. However, their performance depends on information not usually available such as multiple acquisitions, receiver noise matrices, sensitivity coil profiles, reconstruction coefficients, or even biophysical models of the data. Besides, some methods show an undesirable granular pattern on the estimates as a side effect of local estimation. Finally, some methods make strong assumptions that just hold in the case of high signal-to-noise ratio (SNR), which limits their usability in real scenarios. We propose a new automatic noise estimation technique for non-stationary Rician noise that overcomes the aforementioned drawbacks. Its effectiveness is due to the derivation of a variance-stabilizing transformation designed to deal with any SNR. The method was compared to the main state-of-the-art methods in synthetic and real scenarios. Numerical results confirm the robustness of the method and its better performance for the whole range of SNRs.

  2. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI can detect stroke at a very early stage by mapping the motion of water molecules in ... is because traction devices and many types of life support equipment may distort the MR images and ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... images removable dental work pens, pocket knives and eyeglasses body piercings In most cases, an MRI exam ... and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... the exam. MRI scanners are air-conditioned and well-lit. Music may be played through the headphones ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... metallic items, which can distort MRI images removable dental work pens, pocket knives and eyeglasses body piercings ... and send a signed report to your primary care or referring physician, who will share the results ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... a risk, depending on their nature and the strength of the MRI magnet. Many implanted devices will ... full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... tissue from which they come. The MR scanner captures this energy and creates a picture of the ... imaging based on the electrical activity of the heart, such as electrocardiography (EKG). MRI generally is not ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... it may cause some medical devices to malfunction. Most orthopedic implants pose no risk, but you should ... a digital cloud server. Currently, MRI is the most sensitive imaging test of the head (particularly the ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... and may add approximately 15 minutes to the total exam time. top of page What will I ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... distort images of the facial area or brain, so you should let the radiologist know about them. ... MRI units, called short-bore systems , are designed so that the magnet does not completely surround you. ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... to a CD or uploaded to a digital cloud server. Currently, MRI is the most sensitive imaging ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... for Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association ... MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging ( ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... an MRI scan, but this is rare. Tooth fillings and braces usually are not affected by the magnetic field, but they may distort images of the facial area or brain, so you should let the ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... is not harmful, but it may cause some medical devices to malfunction. Most orthopedic implants pose no ... Head? Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose medical conditions. ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... a CD or uploaded to a digital cloud server. Currently, MRI is the most sensitive imaging test ... understanding of the possible charges you will incur. Web page review process: This Web page is reviewed ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... others nearby harm. These items include: jewelry, watches, credit cards and hearing aids, all of which can ... top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging technique that ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... to produce detailed pictures of organs, soft tissues, bone and virtually all other internal body structures. MRI ... discovery of abnormalities that might be obscured by bone with other imaging methods. The contrast material used ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... top of page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for ... Imaging (MRI) - Head Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... used in tattoos may contain iron and could heat up during an MRI scan, but this is ... called MR angiography (MRA) provides detailed images of blood vessels in the brain—often without the need ...

  20. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... On very rare occasions, a few patients experience side effects from the contrast material, including nausea, headache and ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... Examples include but are not limited to: artificial heart valves implanted drug infusion ports artificial limbs or ... imaging based on the electrical activity of the heart, such as electrocardiography (EKG). MRI generally is not ...

  2. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI) procedure View full size with caption Pediatric Content Some imaging tests and treatments have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of the brain and other cranial structures are clearer and more detailed than with other ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... tissue and fluid, known as edema . MRI typically costs more and may take more time to perform ... accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI. For more information, consult your radiologist. The computer workstation that processes the imaging information is located ... not come in contact with the patient. A computer then processes the signals and generates a series ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... of which shows a thin slice of the body. The images can then be studied from different angles by ... information please consult the ACR Manual on Contrast Media and its references. top of page What are the limitations of MRI of the Head? High-quality images are assured only if you are able to ...

  8. Magnetic resonance imaging (MRI

    Directory of Open Access Journals (Sweden)

    Takavar A

    1993-04-01

    Full Text Available Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I, a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D. factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

  9. Magnetic resonance imaging (MRI)

    OpenAIRE

    Takavar A

    1993-01-01

    Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I), a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D.) factors and different image construction techniques based on their different combinations is discussed and at the end physical properties of some N.M.R images is mentioned.

  10. MRI imaging in pediatric appendicitis

    Directory of Open Access Journals (Sweden)

    Robin Riley

    2018-04-01

    Full Text Available An 8-year-old male presents with two days of abdominal pain and emesis. Computed tomography was concerning for obstruction or reactive ileus with an apparent transition point in the right lower quadrant, possibly due to Crohn's. Magnetic resonance imaging was concerning for perforated appendicitis. As demonstrated by this case MRI can be as sensitive as CT in detecting pediatric appendicitis [2]. We recommend using MRI instead of CT to diagnose appendicitis to avoid ionizing radiation and increased cancer risk in the pediatric population. Keywords: Computer tomography, Magnetic resonance imaging, Pediatric appendicitis

  11. Magnetic Resonance Imaging (MRI): Brain (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Brain KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Brain What's in this article? What ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... types of clips used for brain aneurysms some types of metal coils placed within blood vessels nearly all cardiac defibrillators and pacemakers You ... called MR angiography (MRA) provides detailed images of blood vessels in the ... the opening of certain types of MRI machines. The presence of an implant ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... provides detailed images of blood vessels in the brain—often without the need for contrast material. See the MRA page for more information. MRI can detect stroke at a very early stage by mapping the motion of water molecules in the tissue. ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... internal body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... kind, such as an allergy to iodine or x-ray contrast material, drugs, food, or the environment, or ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... very early stage by mapping the motion of water molecules in the tissue. This water motion, known as diffusion, is impaired by most ... the limitations of MRI of the Head? High-quality images are assured only if you are able ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... body structures. MRI does not use ionizing radiation (x-rays). Detailed MR images allow physicians to evaluate various ... kind, such as an allergy to iodine or x-ray contrast material, drugs, food, or the environment, or ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... the equipment look like? How does the procedure work? How is the ... use to diagnose medical conditions. MRI uses a powerful magnetic field, radio frequency ...

  18. On the characterization of single-event related brain activity from functional Magnetic Resonance Imaging (fMRI) measurements

    KAUST Repository

    Khoram, Nafiseh; Zayane, Chadia; Laleg-Kirati, Taous-Meriem; Djellouli, Rabia

    2014-01-01

    We propose an efficient numerical technique for calibrating the mathematical model that describes the singleevent related brain response when fMRI measurements are given. This method employs a regularized Newton technique in conjunction with a

  19. On the characterization of single-event related brain activity from functional Magnetic Resonance Imaging (fMRI) measurements

    KAUST Repository

    Khoram, Nafiseh

    2014-08-01

    We propose an efficient numerical technique for calibrating the mathematical model that describes the singleevent related brain response when fMRI measurements are given. This method employs a regularized Newton technique in conjunction with a Kalman filtering procedure. We have applied this method to estimate the biophysiological parameters of the Balloon model that describes the hemodynamic brain responses. Illustrative results obtained with both synthetic and real fMRI measurements are presented. © 2014 IEEE.

  20. Magnetic Resonance Imaging (MRI): Dynamic Pelvic Floor

    Science.gov (United States)

    ... to a CD or uploaded to a digital cloud server. Dynamic pelvic floor MRI provides detailed pictures ... with you. top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging ...

  1. [MRI methods for pulmonary ventilation and perfusion imaging].

    Science.gov (United States)

    Sommer, G; Bauman, G

    2016-02-01

    Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O2-enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies.

  2. MRI methods for pulmonary ventilation and perfusion imaging

    International Nuclear Information System (INIS)

    Sommer, G.; Bauman, G.

    2016-01-01

    Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O 2 -enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies. (orig.) [de

  3. Imaging features of primary Sarcomas of the great vessels in CT, MRI and PET/CT: a single-center experience

    International Nuclear Information System (INIS)

    Falck, Christian von; Meyer, Bernhard; Fegbeutel, Christine; Länger, Florian; Bengel, Frank; Wacker, Frank; Rodt, Thomas

    2013-01-01

    To investigate the imaging features of primary sarcomas of the great vessels in CT, MRI and 18 F-FDG PET/CT. Thirteen patients with a primary sarcoma of the great vessels were retrospectively evaluated. All available images studies including F-18 FDG PET(/CT) (n = 4), MDCT (n = 12) and MRI (n = 6) were evaluated and indicative image features of this rare tumor entity were identified. The median interval between the first imaging study and the final diagnosis was 11 weeks (0–12 weeks). The most frequently observed imaging findings suggestive of malignant disease in patients with sarcomas of the pulmonary arteries were a large filling defect with vascular distension, unilaterality and a lack of improvement despite effective anticoagulation. In patients with aortic sarcomas we most frequently observed a pedunculated appearance and an atypical location of the filling defect. The F-18 FDG PET(/CT) examinations demonstrated an unequivocal hypermetabolism of the lesion in all cases (4/4). MRI proved lesion vascularization in 5/6 cases. Intravascular unilateral or atypically located filling defects of the great vessels with vascular distension, a pedunculated shape and lack of improvement despite effective anticoagulation are suspicious for primary sarcoma on MDCT or MRI. MR perfusion techniques can add information on the nature of the lesion but the findings may be subtle and equivocal. F-18 FDG PET/CT may have a potential role in these patients and may be considered as part of the imaging workup

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... does not completely surround you. Some newer MRI machines have a larger diameter bore which can be ... size patients or patients with claustrophobia. Other MRI machines are open on the sides (open MRI). Open ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... in the first three to four months of pregnancy unless the potential benefit from the MRI exam ... the MRI Safety page for more information about pregnancy and MRI. If you have claustrophobia (fear of ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... information on the chemicals present in the body's cells, may also be performed during the MRI exam ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  7. Brain Tumor Image Segmentation in MRI Image

    Science.gov (United States)

    Peni Agustin Tjahyaningtijas, Hapsari

    2018-04-01

    Brain tumor segmentation plays an important role in medical image processing. Treatment of patients with brain tumors is highly dependent on early detection of these tumors. Early detection of brain tumors will improve the patient’s life chances. Diagnosis of brain tumors by experts usually use a manual segmentation that is difficult and time consuming because of the necessary automatic segmentation. Nowadays automatic segmentation is very populer and can be a solution to the problem of tumor brain segmentation with better performance. The purpose of this paper is to provide a review of MRI-based brain tumor segmentation methods. There are number of existing review papers, focusing on traditional methods for MRI-based brain tumor image segmentation. this paper, we focus on the recent trend of automatic segmentation in this field. First, an introduction to brain tumors and methods for brain tumor segmentation is given. Then, the state-of-the-art algorithms with a focus on recent trend of full automatic segmentaion are discussed. Finally, an assessment of the current state is presented and future developments to standardize MRI-based brain tumor segmentation methods into daily clinical routine are addressed.

  8. Simultaneous MRI and PET imaging of a rat brain

    International Nuclear Information System (INIS)

    Raylman, Raymond R; Majewski, Stan; Lemieux, Susan K; Velan, S Sendhil; Kross, Brian; Popov, Vladimir; Smith, Mark F; Weisenberger, Andrew G; Zorn, Carl; Marano, Gary D

    2006-01-01

    Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging

  9. Simultaneous MRI and PET imaging of a rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Raylman, Raymond R [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Majewski, Stan [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Lemieux, Susan K [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Velan, S Sendhil [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States); Kross, Brian [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Popov, Vladimir [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Smith, Mark F [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Weisenberger, Andrew G [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Zorn, Carl [Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Newport News, VA (United States); Marano, Gary D [Center for Advanced Imaging, Department of Radiology, Box 9236, West Virginia University, Morgantown, WV (United States)

    2006-12-21

    Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI will allow the correlation of form with function. Our group is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode. Each MRI-PET detector module consists of an array of LSO detector elements coupled through a long fibre optic light guide to a single Hamamatsu flat panel position-sensitive photomultiplier tube (PSPMT). The use of light guides allows the PSPMTs to be positioned outside the bore of a 3T MRI scanner where the magnetic field is relatively small. To test the device, simultaneous MRI and PET images of the brain of a male Sprague Dawley rat injected with FDG were successfully obtained. The images revealed no noticeable artefacts in either image set. Future work includes the construction of a full ring PET scanner, improved light guides and construction of a specialized MRI coil to permit higher quality MRI imaging.

  10. Single-photon imaging

    CERN Document Server

    Seitz, Peter

    2011-01-01

    The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncoooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist´s view from different domains to the forthcoming “single-photon imaging” revolution. The various aspects of single-photon imaging are treated by internati...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... interfere with the magnetic field of the MRI unit, metal and electronic items are not allowed in ... does the equipment look like? The traditional MRI unit is a large cylinder-shaped tube surrounded by ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... women should not have this exam in the first three to four months of pregnancy unless the ... not to have an MRI exam during the first trimester unless medically necessary. MRI may not always ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... conditions. MRI uses a powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... used in MRI exams is less likely to produce an allergic reaction than the iodine-based contrast ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ... Brain Tumors Radiation Therapy for Head and Neck Cancer Others : American Stroke Association National Stroke Association top ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... tissue and fluid, known as edema . MRI typically costs more and may take more time to perform ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI examination poses almost no risk to the average patient when appropriate safety guidelines are followed. If ... tissue and fluid, known as edema . MRI typically costs more and may take more time to perform ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... as severe kidney disease, may prevent you from being given gadolinium contrast for an MRI. If you ... of time after placement (usually six weeks) before being safe for MRI examinations. Examples include but are ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... This detail makes MRI an invaluable tool in early diagnosis and evaluation of many conditions, including tumors. ... information. MRI can detect stroke at a very early stage by mapping the motion of water molecules ...

  20. Multimodal MRI in the characterization of glial neoplasms: the combined role of single-voxel MR spectroscopy, diffusion imaging and echo-planar perfusion imaging

    International Nuclear Information System (INIS)

    Zonari, Paolo; Baraldi, Patrizia; Crisi, Girolamo

    2007-01-01

    Diffusion-weighted imaging (DWI), perfusion-weighted imaging (PWI) and MR spectroscopy (MRS) provide useful data for tumor evaluation. To assess the contribution of these multimodal techniques in grading glial neoplasms, we compared the value of DWI, PWI and MRS in the evaluation of histologically proven high- and low-grade gliomas in a population of 105 patients. Independently for each modality, the following variables were used to compare the tumors: minimum apparent diffusion coefficient (ADC) and maximum relative cerebral blood volume (rCBV) normalized values between tumor and healthy tissue, maximum Cho/Cr ratio and minimum NAA/Cr ratio in tumor, and scored lactate and lipid values in tumor. The Mann-Whitney and Wilcoxon tests were employed to compare DWI, PWI and MRS between tumor types. Logistic regression analysis was used to determine which parameters best increased the diagnostic accuracy in terms of sensitivity, specificity, and positive and negative predictive values. ROC curves were determined for parameters with high sensitivity and specificity to identify threshold values to separate high- from low-grade lesions. Statistically significant differences were found for rCBV tumor/normal tissue ratio, and NAA/Cr ratio in tumor and Cho/Cr ratio in tumor between low- and high-grade tumors. The best performing single parameter for group classification was the normalized rCBV value; including all parameters, statistical significance was reached by rCBV tumor/normal tissue ratio, NAA/Cr tumor ratio and lactate. From the ROC curves, a high probability for a neoplasm to be a high-grade lesion was associated with a rCBV tumor/normal tissue ratio of >1.16 and NAA/Cr tumor ratio of <0.44. Combining PWI and MRS with conventional MR imaging increases the accuracy of the attribution of malignancy to glial neoplasms. The best performing parameter was found to be the perfusion level. (orig.)

  1. PET-MRI and multimodal cancer imaging

    International Nuclear Information System (INIS)

    Wang Taisong; Zhao Jinhua; Song Jianhua

    2011-01-01

    Multimodality imaging, specifically PET-CT, brought a new perspective into the fields of clinical imaging. Clinical cases have shown that PET-CT has great value in clinical diagnosis and experimental research. But PET-CT still bears some limitations. A major drawback is that CT provides only limited soft tissue contrast and exposes the patient to a significant radiation dose. MRI overcome these limitations, it has excellent soft tissue contrast, high temporal and spatial resolution and no radiation damage. Additionally, since MRI provides also functional information, PET-MRI will show a new direction of multimodality imaging in the future. (authors)

  2. MRI Reporter Genes for Noninvasive Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Caixia Yang

    2016-05-01

    Full Text Available Magnetic resonance imaging (MRI is one of the most important imaging technologies used in clinical diagnosis. Reporter genes for MRI can be applied to accurately track the delivery of cell in cell therapy, evaluate the therapy effect of gene delivery, and monitor tissue/cell-specific microenvironments. Commonly used reporter genes for MRI usually include genes encoding the enzyme (e.g., tyrosinase and β-galactosidase, the receptor on the cells (e.g., transferrin receptor, and endogenous reporter genes (e.g., ferritin reporter gene. However, low sensitivity limits the application of MRI and reporter gene-based multimodal imaging strategies are common including optical imaging and radionuclide imaging. These can significantly improve diagnostic efficiency and accelerate the development of new therapies.

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info About Us News Physician ... absolutely necessary for medical treatment. See the MRI Safety page for more information about pregnancy and MRI. ...

  4. Single-photon imaging

    International Nuclear Information System (INIS)

    Seitz, Peter; Theuwissen, Albert J.P.

    2011-01-01

    The acquisition and interpretation of images is a central capability in almost all scientific and technological domains. In particular, the acquisition of electromagnetic radiation, in the form of visible light, UV, infrared, X-ray, etc. is of enormous practical importance. The ultimate sensitivity in electronic imaging is the detection of individual photons. With this book, the first comprehensive review of all aspects of single-photon electronic imaging has been created. Topics include theoretical basics, semiconductor fabrication, single-photon detection principles, imager design and applications of different spectral domains. Today, the solid-state fabrication capabilities for several types of image sensors has advanced to a point, where uncooled single-photon electronic imaging will soon become a consumer product. This book is giving a specialist's view from different domains to the forthcoming ''single-photon imaging'' revolution. The various aspects of single-photon imaging are treated by internationally renowned, leading scientists and technologists who have all pioneered their respective fields. (orig.)

  5. Imaging features of colovesical fistulae on MRI.

    Science.gov (United States)

    Tang, Y Z; Booth, T C; Swallow, D; Shahabuddin, K; Thomas, M; Hanbury, D; Chang, S; King, C

    2012-10-01

    MRI is routinely used in the investigation of colovesical fistulae at our institute. Several papers have alluded to its usefulness in achieving the diagnosis; however, there is a paucity of literature on its imaging findings. Our objective was to quantify the MRI characteristics of these fistulae. We selected all cases over a 4-year period with a final clinical diagnosis of colovesical fistula which had been investigated with MRI. The MRI scans were reviewed in a consensus fashion by two consultant uroradiologists. Their MRI features were quantified. There were 40 cases of colovesical fistulae. On MRI, the fistula morphology consistently fell into three patterns. The most common pattern (71%) demonstrated an intervening abscess between the bowel wall and bladder wall. The second pattern (15%) had a visible track between the affected bowel and bladder. The third pattern (13%) was a complete loss of fat plane between the affected bladder and bowel wall. MRI correctly determined the underlying aetiology in 63% of cases. MRI is a useful imaging modality in the diagnosis of colovesical fistulae. The fistulae appear to have three characteristic morphological patterns that may aid future diagnoses of colovesical fistulae. To the authors' knowledge, this is the first publication of the MRI findings in colovesical fistulae.

  6. Imaging brain microstructure with diffusion MRI

    DEFF Research Database (Denmark)

    Alexander, Daniel C; Dyrby, Tim B; Nilsson, Markus

    2018-01-01

    This article gives an overview of microstructure imaging of the brain with diffusion MRI and reviews the state of the art. The microstructure-imaging paradigm aims to estimate and map microscopic properties of tissue using a model that links these properties to the voxel scale MR signal. Imaging ...

  7. Centrically reordered inversion recovery half-Fourier single-shot turbo spin-echo sequence: improvement of the image quality of oxygen-enhanced MRI

    International Nuclear Information System (INIS)

    Ohno, Yoshiharu; Hatabu, Hiroto; Higashino, Takanori; Kawamitsu, Hideaki; Watanabe, Hirokazu; Takenaka, Daisuke; Cauteren, Marc van; Sugimura, Kazuro

    2004-01-01

    Purpose: The purpose of the study presented here was to determine the improvement in image quality of oxygen-enhanced magnetic resonance (MR) subtraction imaging obtained with a centrically reordered inversion recovery half-Fourier single-shot turbo spin-echo (c-IR-HASTE) sequence compared with that obtained with a conventional sequentially reordered inversion recovery single-shot HASTE (s-IR-HASTE) sequence for pulmonary imaging. Materials and methods: Oxygen-enhanced MR imaging using a 1.5 T whole body scanner was performed on 12 healthy, non-smoking volunteers. Oxygen-enhanced MR images were obtained with the coronal two-dimensional (2D) c-IR-HASTE sequence and 2D s-IR-HASTE sequence combined with respiratory triggering. For a 256x256 matrix, 132 phase-encoding steps were acquired including four steps for phase correction. Inter-echo spacing for each sequence was 4.0 ms. The effective echo time (TE) for c-IR-HASTE was 4.0 ms, and 16 ms for s-IR-HASTE. The inversion time (TI) was 900 ms. To determine the improvement in oxygen-enhanced MR subtraction imaging by c-IR-HASTE, CNRs of subtraction image, overall image quality, and image degradation of the c-IR-HASTE and s-IR-HASTE techniques were statistically compared. Results: CNR, overall image quality, and image degradation of c-IR-HASTE images showed significant improvement compared to those s-IR-HASTE images (P<0.05). Conclusion: Centrically reordered inversion recovery half-Fourier single-shot turbo spin-echo (c-IR-HASTE) sequence enhanced the signal from the lung and improved the image quality of oxygen-enhanced MR subtraction imaging

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... told otherwise, take your regular medications as usual. Leave jewelry at home and wear loose, comfortable clothing. ... contrast material except when absolutely necessary for medical treatment. See the MRI Safety page for more information ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given gadolinium contrast ... an MRI. If you have a history of kidney disease or liver transplant, it will be necessary to ...

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    Full Text Available ... scans, MRI does not utilize ionizing radiation. Instead, radiofrequency pulses re-align hydrogen atoms that naturally exist ... thumping sounds when the coils that generate the radiofrequency pulses are activated. Some centers provide earplugs, while ...

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    Full Text Available ... tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces within the brain (ventricles) causes of epilepsy ( ... may not always distinguish between cancer tissue and fluid, known as edema . MRI typically costs more and ...

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    Full Text Available ... the head (particularly the brain) in routine clinical practice. top of page What are some common uses ... gadolinium contrast material except when absolutely necessary for medical treatment. See the MRI Safety page for more ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... devices or metal in your body. Guidelines about eating and drinking before your exam vary between facilities. ... fitting and has no metal fasteners. Guidelines about eating and drinking before an MRI exam vary with ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... three to four months of pregnancy unless the potential benefit from the MRI exam is assumed to outweigh the potential risks. Pregnant women should not receive injections of ...

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    Full Text Available ... traditional MRI unit is a large cylinder-shaped tube surrounded by a circular magnet. You will lie ... your skin at the site of the IV tube insertion. Some patients may sense a temporary metallic ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... metal in your body. Guidelines about eating and drinking before your exam vary between facilities. Unless you ... has no metal fasteners. Guidelines about eating and drinking before an MRI exam vary with the specific ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... not use ionizing radiation and may require an injection of a contrast material called gadolinium, which is ... MRI examinations may require you to receive an injection of contrast material into the bloodstream. The radiologist , ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... will be removed. MRI exams generally include multiple runs (sequences), some of which may last several minutes. ... top of page Who interprets the results and how do I get them? A radiologist, a physician ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ...

  20. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... you should let the radiologist know about them. Parents or family members who accompany patients into the ... intercom. Many MRI centers allow a friend or parent to stay in the room as long as ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... will hear and feel loud tapping or thumping sounds when the coils that generate the radiofrequency pulses ... use headphones to reduce the intensity of the sounds made by the MRI machine. You may be ...

  2. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... are not limited to: artificial heart valves implanted drug infusion ports artificial limbs or metallic joint prostheses ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... take food and medications as usual. Some MRI examinations may require you to receive an injection of ... for a mild sedative prior to your scheduled examination. Jewelry and other accessories should be left at ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces within the brain (ventricles) causes of epilepsy (seizure) ... MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want to ask your ...

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    Full Text Available ... magnetic field of the MRI unit, metal and electronic items are not allowed in the exam room. ... tell the technologist if you have medical or electronic devices in your body. These objects may interfere ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. ... signals that are detected by the coils. The electric current does not come in contact with the ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... have any devices or metal in your body. Guidelines about eating and drinking before your exam vary ... is loose-fitting and has no metal fasteners. Guidelines about eating and drinking before an MRI exam ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... the head (particularly the brain) in routine clinical practice. top of page What are some common uses ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ...

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    Full Text Available ... can help diagnose conditions such as: brain tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces ... MRA page for more information. MRI can detect stroke at a very early stage by mapping the ...

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    Full Text Available ... procedure performed? MRI examinations may be performed on outpatients or inpatients. You will be positioned on the ... and send a signed report to your primary care or referring physician, who will share the results ...

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    Full Text Available ... about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones ...

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    Full Text Available ... used in tattoos may contain iron and could heat up during an MRI scan, but this is ... injection. If you do not require sedation, no recovery period is necessary. You may resume your usual ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI exam, a physician, nurse or technologist will insert an intravenous (IV) catheter, also known as an ... physicians with expertise in several radiologic areas. Outside links: For the convenience of our users, RadiologyInfo .org ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain ... the web pages found at these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... you have any devices or metal in your body. Guidelines about eating and drinking before your exam ... soft tissues, bone and virtually all other internal body structures. MRI does not use ionizing radiation (x- ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI) of the head uses a powerful magnetic field, radio waves and a computer to produce detailed ... there’s a possibility you are pregnant. The magnetic field is not harmful, but it may cause some ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... allergies and whether there’s a possibility you are pregnant. The magnetic field is not harmful, but it ... if there is any possibility that they are pregnant. MRI has been used for scanning patients since ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... of many conditions, including tumors. MRI enables the discovery of abnormalities that might be obscured by bone ... Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise in several radiologic ...

  20. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help you pass the time. In some cases, intravenous injection of contrast material ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... The contrast material used in MRI exams is less likely to produce an allergic reaction than the ...

  2. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... detailed pictures of the brain and other cranial structures that are clearer and more detailed than other ... tissues, bone and virtually all other internal body structures. MRI does not use ionizing radiation (x-rays). ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... and send a signed report to your primary care or referring physician, who will share the results ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation Therapy for Head and ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... The magnetic field is produced by passing an electric current through wire coils in most MRI units. Other coils, located in the machine and in some cases, placed around the part ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... into the bloodstream. The radiologist , technologist or a nurse may ask if you have allergies of any ... be used in the MRI exam, a physician, nurse or technologist will insert an intravenous (IV) catheter, ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... may follow your regular daily routine and take food and medications as usual. Some MRI examinations may ... to iodine or x-ray contrast material, drugs, food, or the environment, or if you have asthma. ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... any recent surgeries. Some conditions, such as severe kidney disease, may prevent you from being given gadolinium ... an MRI. If you have a history of kidney disease or liver transplant, it will be necessary ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... your regular medications as usual. Leave jewelry at home and wear loose, comfortable clothing. You may be ... Jewelry and other accessories should be left at home, if possible, or removed prior to the MRI ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will ... data suggest that it is safe to continue breastfeeding after receiving intravenous contrast. For further information please ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... used in tattoos may contain iron and could heat up during an MRI scan, but this is ... from the contrast material, including nausea, headache and pain at the site of injection. Similarly, patients are ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... contrast material in patients with very poor kidney function. Careful assessment of kidney function before considering a ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... it is useful to bring that to the attention of the scheduler before the exam and bring ... bore which can be more comfortable for larger size patients or patients with claustrophobia. Other MRI machines ...

  14. Multimodality imaging: transfer and fusion of SPECT and MRI data

    International Nuclear Information System (INIS)

    Knesaurek, K.

    1994-01-01

    Image fusion is a technique which offers the best of both worlds. It unites the two basic types of medical images: functional body images(PET or SPECT scans), which provide physiological information, and structural images (CT or MRI), which provide an anatomic map of the body. Control-point based registration technique was developed and used. Tc-99m point sources were used as external markers in SPECT studies while, for MRI and CT imaging only anatomic landmarks were used as a control points. The MRI images were acquired on GE Signa 1.2 system and CT data on a GE 9800 scanner. SPECT studies were performed 1h after intravenous injection of the 740 MBq of the Tc-99m-HMPAO on the triple-headed TRIONIX gamma camera. B-spline and bilinear interpolation were used for the rotation, scaling and translation of the images. In the process of creation of a single composite image, in order to retain information from the individual images, MRI (or CT) image was scaled to one color range and a SPECT image to another. In some situations the MRI image was kept black-and-white while the SPECT image was pasted on top of it in 'opaque' mode. Most errors which propagate through the matching process are due to sample size, imperfection of the acquisition system, noise and interpolations used. Accuracy of the registration was investigated by SPECT-CT study performed on a phantom study. The results has shown that accuracy of the matching process is better, or at worse, equal to 2 mm. (author)

  15. Neuroimaging of language processes: fMRI of silent and overt lexical processing and the promise of multiple process imaging in single brain studies

    International Nuclear Information System (INIS)

    Borowsky, R.; Owen, W.J.; Wile, T.L.; Friesen, C.K.; Martin, J.L.; Sarty, G.E.

    2005-01-01

    To implement and evaluate a multiple-process functional magnetic resonance imaging (fMRI) paradigm designed to effectively and efficiently activate several language-related regions for use with neurosurgical patients. Both overt and covert response conditions were examined. The fMRI experiments compared the traditional silent word-generation condition versus an overt one as they engage frontal language regions (Experiment 1) and silent versus overt semantic association conditions as they engage multiple language processing regions (Experiment 2). In Experiment 1 the overt condition yielded greater magnitude of activation, but not volume of activation, in the left inferior frontal and insular cortices than did the silent condition for most, but not all, participants. Experiment 2 demonstrated that the activation of multiple established language processing regions (ie, orthographic, phonological and semantic) can be achieved in a significant number of participants, particularly under overt semantic association conditions and that such activation varies in predictable ways. The traditional silent response condition cannot be considered as equivalent to the overt response condition during word generation or semantic association. The multiple-process imaging method introduced here was sensitive to processing robust orthographic, phonological, and semantic regions, particularly under the overt response condition. (author)

  16. Initial tests of a prototype MRI-compatible PET imager

    International Nuclear Information System (INIS)

    Raylman, Raymond R.; Majewski, Stan; Lemieux, Susan; Velan, S. Sendhil; Kross, Brain; Popov, Vladimir; Smith, Mark F.; Weisenberger, Andrew G.; Wojcik, Randy

    2006-01-01

    Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5x5x4 cm 3 . Each MRI-PET detector module consists of an array of LSO detector elements (2.5x2.5x15 mm 3 ) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of ∼60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to ∼85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy

  17. Initial tests of a prototype MRI-compatible PET imager

    Energy Technology Data Exchange (ETDEWEB)

    Raylman, Raymond R. [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States)]. E-mail: rraylman@wvu.edu; Majewski, Stan [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Lemieux, Susan [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States); Velan, S. Sendhil [Center for Advanced Imaging, Department of Radiology, West Virginia University, HSB Box 9236, Morgantown, WV (United States); Kross, Brain [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Popov, Vladimir [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Smith, Mark F. [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Weisenberger, Andrew G. [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Wojcik, Randy [Detector Group, Physics Division, Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2006-12-20

    Multi-modality imaging is rapidly becoming a valuable tool in the diagnosis of disease and in the development of new drugs. Functional images produced with PET fused with anatomical structure images created by MRI, will allow the correlation of form with function. Our group (a collaboration of West Virginia University and Jefferson Lab) is developing a system to acquire MRI and PET images contemporaneously. The prototype device consists of two opposed detector heads, operating in coincidence mode with an active FOV of 5x5x4 cm{sup 3}. Each MRI-PET detector module consists of an array of LSO detector elements (2.5x2.5x15 mm{sup 3}) coupled through a long fiber optic light guide to a single Hamamatsu flat panel PSPMT. The fiber optic light guide is made of a glued assembly of 2 mm diameter acrylic fibers with a total length of 2.5 m. The use of a light guides allows the PSPMTs to be positioned outside the bore of the 3 T General Electric MRI scanner used in the tests. Photon attenuation in the light guides resulted in an energy resolution of {approx}60% FWHM, interaction of the magnetic field with PSPMT further reduced energy resolution to {approx}85% FWHM. Despite this effect, excellent multi-plane PET and MRI images of a simple disk phantom were acquired simultaneously. Future work includes improved light guides, optimized magnetic shielding for the PSPMTs, construction of specialized coils to permit high-resolution MRI imaging, and use of the system to perform simultaneous PET and MRI or MR-spectroscopy.

  18. Developments in boron magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Schweizer, M.

    1995-01-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... procedure work? How is the procedure performed? What will I experience during and after the procedure? Who interprets the results and how do I get them? What are the benefits vs. risks? What are the limitations of MRI ...

  20. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... have allergies of any kind, such as an allergy to iodine or x-ray contrast material, drugs, food, or the environment, or if you have asthma. The contrast material most commonly used for an MRI exam contains a metal ... in patients with iodine contrast allergy. It is far less common for a patient ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... also screened for safety in the magnetic environment. Children will be given appropriately sized earplugs or headphones during the exam. MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ...

  2. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... to have an allergy to a gadolinium-based contrast agent used for MRI than the iodine-containing contrast ... more information on adverse reactions to gadolinium-based contrast agents, please consult the ACR Manual on Contrast Media . ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... which they come. The MR scanner captures this energy and creates a picture of the tissues scanned based on this information. The magnetic field is produced by passing an electric current through wire coils in most MRI units. ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... contrast for an MRI. If you have a history of kidney disease or liver transplant, it will be necessary to perform a blood test to determine whether the kidneys are functioning adequately. Women should always inform their physician or technologist if ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... able to see, hear and speak with you at all times using a two-way intercom. Many MRI centers allow a friend or parent to stay in the room as long as they are also screened for safety in the magnetic environment. Children will be given ...

  6. Music-supported therapy induces plasticity in the sensorimotor cortex in chronic stroke: a single-case study using multimodal imaging (fMRI-TMS).

    Science.gov (United States)

    Rojo, Nuria; Amengual, Julian; Juncadella, Montserrat; Rubio, Francisco; Camara, Estela; Marco-Pallares, Josep; Schneider, Sabine; Veciana, Misericordia; Montero, Jordi; Mohammadi, Bahram; Altenmüller, Eckart; Grau, Carles; Münte, Thomas F; Rodriguez-Fornells, Antoni

    2011-01-01

    Music-Supported Therapy (MST) has been developed recently in order to improve the use of the affected upper extremity after stroke. This study investigated the neuroplastic mechanisms underlying effectiveness in a patient with chronic stroke. MST uses musical instruments, a midi piano and an electronic drum set emitting piano sounds, to retrain fine and gross movements of the paretic upper extremity. Data are presented from a patient with a chronic stroke (20 months post-stroke) with residual right-sided hemiparesis who took part in 20 MST sessions over the course of 4 weeks. Post-therapy, a marked improvement of movement quality, assessed by 3D movement analysis, was observed. Moreover, functional magnetic resonance imaging (fMRI) of a sequential hand movement revealed distinct therapy-related changes in the form of a reduction of excess contralateral and ipsilateral activations. This was accompanied by changes in cortical excitability evidenced by transcranial magnetic stimulation (TMS). Functional MRI in a music listening task suggests that one of the effects of MST is the task-dependent coupling of auditory and motor cortical areas. The MST appears to be a useful neurorehabilitation tool in patients with chronic stroke and leads to neural reorganization in the sensorimotor cortex.

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... you! Do you have a personal story about radiology? Share your patient story here Images × Image Gallery ... reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of North America ( ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... imaging modalities. top of page Additional Information and Resources RTAnswers.org : Radiation Therapy for Brain Tumors Radiation ... To locate a medical imaging or radiation oncology provider in your community, you can search the ACR- ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... is done because a potential abnormality needs further evaluation with additional views or a special imaging technique. ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... a radiologist or other physician. To locate a medical imaging or radiation oncology provider in your community, you ... not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... metallic objects. Patient movement can have the same effect. A very irregular heartbeat may affect the quality of images obtained using techniques that time the imaging based on the electrical activity of ...

  12. Actual imaging time in fetal MRI

    International Nuclear Information System (INIS)

    Brugger, Peter C.; Prayer, Daniela

    2012-01-01

    Objective: Safety issues in magnetic resonance imaging (MRI) are important, especially in fetal MRI. However, since basic data with respect of the effective exposure time in fetal MRI are not available, this study aimed to determine the actual imaging time during a fetal MRI study. Methods: 100 fetal MRI studies of singleton pregnancies performed on a 1.5 T system were analysed with respect to study duration (from starting the survey scan until the end of study), the number of sequences acquired, and the actual imaging time, which was calculated by adding up scan time of each sequence. Furthermore, each sequence type was analysed regarding the number of acquisitions, specific absorption rates (SAR), and duration. Results: Mean study duration was 34.6 min (range: 14–58 min; standard deviation (SD): 9.7 min), the average number of sequences acquired was 26.6 (range: 11–44, SD: 6.6). Actual scan time averaged 11.4 min (range: 4–19 min, SD: 4.0 min). Ultrafast T2-weighted and steady-state free-precession sequences accounted for 62.3% of actual scan time, and were distributed over the whole duration of the study. Conclusion: Actual imaging time only accounts for 33% of total study time and is not continuous. The remaining time is consumed by the preparation phases of the scanner, and is spent with planning sequences and the eventual repositioning of the coil and/or pregnant woman. These data may help to more accurately estimate the exposure to radiofrequency deposition and noise during fetal MRI studies.

  13. Magnetic Resonance Imaging (MRI): Lumbar Spine (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Magnetic Resonance Imaging (MRI): Lumbar Spine KidsHealth / For Parents / Magnetic Resonance Imaging (MRI): Lumbar Spine What's in this article? ...

  14. Towards molecular imaging by means of MRI

    NARCIS (Netherlands)

    Norek, M.

    2008-01-01

    The work presented in the thesis is focused on the design of highly efficient contrast agents for molecular imaging by means of MRI based on the detailed physical characterization of the given material. Specifically, attention is paid on the development of contrast agents for magnetic fields higher

  15. Pharmaceutical applications of magnetic resonance imaging (MRI).

    Science.gov (United States)

    Richardson, J Craig; Bowtell, Richard W; Mäder, Karsten; Melia, Colin D

    2005-06-15

    Magnetic resonance imaging (MRI) is a powerful imaging modality that provides internal images of materials and living organisms on a microscopic and macroscopic scale. It is non-invasive and non-destructive, and one of very few techniques that can observe internal events inside undisturbed specimens in situ. It is versatile, as a wide range of NMR modalities can be accessed, and 2D and 3D imaging can be undertaken. Despite widespread use and major advances in clinical MRI, it has seen limited application in the pharmaceutical sciences. In vitro studies have focussed on drug release mechanisms in polymeric delivery systems, but isolated studies of bioadhesion, tablet properties, and extrusion and mixing processes illustrate the wider potential. Perhaps the greatest potential however, lies in investigations of pharmaceuticals in vivo, where pilot human and animal studies have demonstrated we can obtain unique insights into the behaviour of gastrointestinal, topical, colloidal, and targeted drug delivery systems.

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... you, notify the radiologist or technologist. It is important that you remain perfectly still while the images are being obtained, which is typically only a few seconds to a few minutes at a time. You will know when images are being recorded ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... examination poses almost no risk to the average patient when appropriate safety guidelines are followed. If sedation is used, there ... have a personal story about radiology? Share your patient story here Images ... Disease Head Injury Brain Tumors Images related ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos ... the body and determine the presence of certain diseases. The images can then be examined on a ...

  19. Imaging tools to study pharmacology: functional MRI on small rodents

    OpenAIRE

    Elisabeth eJonckers; Disha eShah; Julie eHamaide; Marleen eVerhoye; Annemie eVan Der Linden

    2015-01-01

    Functional Magnetic Resonance Imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimu...

  20. FWFusion: Fuzzy Whale Fusion model for MRI multimodal image ...

    Indian Academy of Sciences (India)

    Hanmant Venketrao Patil

    2018-03-14

    Mar 14, 2018 ... consider multi-modality medical images other than PET and MRI images. ... cipal component averaging based on DWT for fusing CT-. MRI and MRI ..... sub-band LH of the fused image, the distance measure is given based on the ...... sustainable integrated dynamic ship routing and scheduling optimization.

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site ...

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    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... medical imaging or radiation oncology provider in your community, you can search the ACR-accredited facilities database . ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... experience some bruising. There is also a very small chance of irritation of your skin at the ... a result, must be kept away from the area to be imaged. Furthermore, the examination takes longer ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... processes the imaging information is located in a separate room from the scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... images can then be examined on a computer monitor, transmitted electronically, printed or copied to a CD ... excessive sedation. However, the technologist or nurse will monitor your vital signs to minimize this risk. Although ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... eating and drinking before your exam vary between facilities. Unless you are told otherwise, take your regular ... with the specific exam and with the imaging facility. Unless you are told otherwise, you may follow ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... This website does not provide cost information. The costs for specific medical imaging tests, treatments and procedures may vary by geographic region. Discuss the fees associated with your prescribed procedure with your doctor, ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... radiation oncology provider in your community, you can search the ACR-accredited facilities database . This website does not provide cost information. The costs for specific medical imaging tests, treatments ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... with metal implants, except for a few types. People with the following implants cannot be scanned and ... it difficult to lie still during imaging. A person who is very large may not fit into ...

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Magnetic ...

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    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... gadolinium contrast, it may still be possible to use it after appropriate pre-medication. Patient consent will ...

  12. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... type your comment or suggestion into the following text box: Comment: E-mail: Area code: Phone no: Thank ... View full size with caption Pediatric Content Some imaging tests ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... determine the presence of certain diseases. The images can then be examined on a computer monitor, transmitted ... of abrupt onset or long-standing symptoms. It can help diagnose conditions such as: brain tumors stroke ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... for scanning patients since the 1980s with no reports of any ill effects on pregnant women or ... will analyze the images and send a signed report to your primary care or referring physician, who ...

  15. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... you should let the radiologist know about them. Parents or family members who accompany patients into the ... part of the body being imaged, send and receive radio waves, producing signals that are detected by ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... for immediate assistance. Manufacturers of intravenous contrast indicate mothers should not breastfeed their babies for 24-48 ...

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... the area of your body being imaged to feel slightly warm, but if it bothers you, notify ... are being recorded because you will hear and feel loud tapping or thumping sounds when the coils ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... is because traction devices and many types of life support equipment may distort the MR images and ...

  19. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index ...

  20. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... images and send a signed report to your primary care or referring physician, who will share the ... Society of Urogenital Radiology note that the available data suggest that it is safe to continue breastfeeding ...

  1. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... a computer to produce detailed pictures of the brain and other cranial structures that are clearer and ... sensitive imaging test of the head (particularly the brain) in routine clinical practice. top of page What ...

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    Full Text Available ... practice. top of page What are some common uses of the procedure? MR imaging of the head ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  3. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... be necessary. Your doctor will explain the exact reason why another exam is requested. Sometimes a follow- ... necessary in trauma situations. Although there is no reason to believe that magnetic resonance imaging harms the ...

  4. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... no: Thank you! Do you have a personal story about radiology? Share your patient story here Images × ... Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2018 Radiological Society of North America, Inc. ( ...

  5. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... produce detailed pictures of the brain and other cranial structures that are clearer and more detailed than ... cases. MR images of the brain and other cranial structures are clearer and more detailed than with ...

  6. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... scanner. top of page How does the procedure work? Unlike conventional x-ray examinations and computed tomography ( ... the same effect. A very irregular heartbeat may affect the quality of images obtained using techniques that ...

  7. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... have a history of kidney disease or liver transplant, it will be necessary to perform a blood ... discovery of abnormalities that might be obscured by bone with other imaging methods. The contrast material used ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... Detailed MR images allow physicians to evaluate various parts of the body and determine the presence of ... Patients who might have metal objects in certain parts of their bodies may also require an x- ...

  9. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... radiology examinations, will analyze the images and send a signed report to your primary care or referring physician, who will share the results with you. Follow-up examinations may be necessary. Your doctor will ... exam is requested. Sometimes a follow-up exam is done because a potential ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... epilepsy (seizure) hemorrhage in selected trauma patients certain chronic conditions, such as multiple sclerosis disorders of the ... a very small chance of irritation of your skin at the site of the IV tube insertion. Some ... Images related to Magnetic ...

  11. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us ... they may move during the scan, possibly causing blindness. Dyes used in tattoos may contain iron and ...

  12. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... the head uses a powerful magnetic field, radio waves and a computer to produce detailed pictures of the brain and other cranial structures that are clearer and more detailed than other imaging methods. This exam does not use ionizing radiation and may require an injection of a ...

  13. Functional Imaging: CT and MRI

    OpenAIRE

    van Beek, Edwin JR; Hoffman, Eric A

    2008-01-01

    Numerous imaging techniques permit evaluation of regional pulmonary function. Contrast-enhanced CT methods now allow assessment of vasculature and lung perfusion. Techniques using spirometric controlled MDCT allow for quantification of presence and distribution of parenchymal and airway pathology, Xenon gas can be employed to assess regional ventilation of the lungs and rapid bolus injections of iodinated contrast agent can provide quantitative measure of regional parenchymal perfusion. Advan...

  14. Imaging gait analysis: An fMRI dual task study.

    Science.gov (United States)

    Bürki, Céline N; Bridenbaugh, Stephanie A; Reinhardt, Julia; Stippich, Christoph; Kressig, Reto W; Blatow, Maria

    2017-08-01

    In geriatric clinical diagnostics, gait analysis with cognitive-motor dual tasking is used to predict fall risk and cognitive decline. To date, the neural correlates of cognitive-motor dual tasking processes are not fully understood. To investigate these underlying neural mechanisms, we designed an fMRI paradigm to reproduce the gait analysis. We tested the fMRI paradigm's feasibility in a substudy with fifteen young adults and assessed 31 healthy older adults in the main study. First, gait speed and variability were quantified using the GAITRite © electronic walkway. Then, participants lying in the MRI-scanner were stepping on pedals of an MRI-compatible stepping device used to imitate gait during functional imaging. In each session, participants performed cognitive and motor single tasks as well as cognitive-motor dual tasks. Behavioral results showed that the parameters of both gait analyses, GAITRite © and fMRI, were significantly positively correlated. FMRI results revealed significantly reduced brain activation during dual task compared to single task conditions. Functional ROI analysis showed that activation in the superior parietal lobe (SPL) decreased less from single to dual task condition than activation in primary motor cortex and in supplementary motor areas. Moreover, SPL activation was increased during dual tasks in subjects exhibiting lower stepping speed and lower executive control. We were able to simulate walking during functional imaging with valid results that reproduce those from the GAITRite © gait analysis. On the neural level, SPL seems to play a crucial role in cognitive-motor dual tasking and to be linked to divided attention processes, particularly when motor activity is involved.

  15. Advanced MRI increases the diagnostic accuracy of recurrent glioblastoma: Single institution thresholds and validation of MR spectroscopy and diffusion weighted MR imaging

    Directory of Open Access Journals (Sweden)

    Tomas Kazda

    2016-01-01

    Full Text Available The accurate identification of glioblastoma progression remains an unmet clinical need. The aim of this prospective single-institutional study is to determine and validate thresholds for the main metabolite concentrations obtained by MR spectroscopy (MRS and the values of the apparent diffusion coefficient (ADC to enable distinguishing tumor recurrence from pseudoprogression. Thirty-nine patients after the standard treatment of a glioblastoma underwent advanced imaging by MRS and ADC at the time of suspected recurrence — median time to progression was 6.7 months. The highest significant sensitivity and specificity to call the glioblastoma recurrence was observed for the total choline (tCho to total N-acetylaspartate (tNAA concentration ratio with the threshold ≥1.3 (sensitivity 100.0% and specificity 94.7%. The ADCmean value higher than 1313 × 10−6 mm2/s was associated with the pseudoprogression (sensitivity 98.3%, specificity 100.0%. The combination of MRS focused on the tCho/tNAA concentration ratio and the ADCmean value represents imaging methods applicable to early non-invasive differentiation between a glioblastoma recurrence and a pseudoprogression. However, the institutional definition and validation of thresholds for differential diagnostics is needed for the elimination of setup errors before implementation of these multimodal imaging techniques into clinical practice, as well as into clinical trials.

  16. Multiparametric and molecular imaging of breast tumors with MRI and PET/MRI

    International Nuclear Information System (INIS)

    Pinker, K.; Marino, M.A.; Meyer-Baese, A.; Helbich, T.H.

    2016-01-01

    Magnetic resonance imaging (MRI) of the breast is an indispensable tool in breast imaging for many indications. Several functional parameters with MRI and positron emission tomography (PET) have been assessed for imaging of breast tumors and their combined application is defined as multiparametric imaging. Available data suggest that multiparametric imaging using different functional MRI and PET parameters can provide detailed information about the hallmarks of cancer and may provide additional specificity. Multiparametric and molecular imaging of the breast comprises established MRI parameters, such as dynamic contrast-enhanced MRI, diffusion-weighted imaging (DWI), MR proton spectroscopy ( 1 H-MRSI) as well as combinations of radiological and MRI techniques (e.g. PET/CT and PET/MRI) using radiotracers, such as fluorodeoxyglucose (FDG). Multiparametric and molecular imaging of the breast can be performed at different field-strengths (range 1.5-7 T). Emerging parameters comprise novel promising techniques, such as sodium imaging ( 23 Na MRI), phosphorus spectroscopy ( 31 P-MRSI), chemical exchange saturation transfer (CEST) imaging, blood oxygen level-dependent (BOLD) and hyperpolarized MRI as well as various specific radiotracers. Multiparametric and molecular imaging has multiple applications in breast imaging. Multiparametric and molecular imaging of the breast is an evolving field that will enable improved detection, characterization, staging and monitoring for personalized medicine in breast cancer. (orig.) [de

  17. Imaging of abdominal tumours: CT or MRI?

    International Nuclear Information System (INIS)

    Olsen, Oeystein E.

    2009-01-01

    The scope of this review is to discuss a theoretical approach to imaging policy, particularly in the perspective of radiation risk reduction. Decisions are ideally driven by empirical evidence about efficacy and risk, e.g., in classical hierarchical efficacy model. As a result of the paucity of empirical evidence (inevitable because of rapid technological development), a pragmatic model is needed. This should avoid overemphasis of factors that currently seem to hamper change, namely personal preference, local expertise, infrastructure, availability. Extrapolation of current general knowledge about CT and MRI demonstrates how a pragmatic approach can be applied in the real world with intermediate goals such as (1) channeling patients from CT to MRI, and (2) reducing CT-delivered radiation. Increased utilisation of MRI in body imaging requires optimisation of scan protocols and equipment, and, being a very operator-dependent modality, the active involvement of the radiologist. In CT dose reduction the main challenge is to benchmark the minimum radiation-dose requirement, and therefore the minimum required image quality that is diagnostically acceptable. As this will ultimately depend on pre-test likelihoods in institutional populations, it is difficult to issue general guidance, and local assessment remains a cornerstone in this effort. (orig.)

  18. Magnetic resonance imaging (MRI) in the diagnosis of neuromuscular diseases

    International Nuclear Information System (INIS)

    Schalke, B.C.G.; Rohkamm, R.; Kaiser, W.

    1990-01-01

    In the last few years imaging procedures became also important in the diagnosis of neuromuscular diseases. We examined more than 150 patients with different neuromuscular diseases with MRI. Conventional diagnostic procedures like EMG, muscle biopsy can not be replaced by imaging procedures. MRI gives the chance to get additional diagnostic informations. It is possible to determine exact distribution and intensity of pathological changes in the muscle. Inflammatory muscle diseases can be differrentiated by T1/T2 values from atrophic/dystrophic diseases. The resolving power is very high and allows the exact detection of affected areas even in a single muscle. This can help to reduce false negative muscle biopsies. This is very useful in children and young adults. MRI can be used for the early detection of genetic myopathies and neuropathies. MRI allows to examine all muscles, including the heart, bone artefacts are absent. Heart muscle involvement in neuromuscular diseases can directly be shown by this method without any risk for the patient. In addition P-spectroscopy can be done for better understanding of pathogenesis, especially if the exact distribution of pathological changes is known. (author)

  19. Photo-magnetic imaging: resolving optical contrast at MRI resolution

    International Nuclear Information System (INIS)

    Lin Yuting; Thayer, David; Luk, Alex L; Gulsen, Gultekin; Gao Hao

    2013-01-01

    In this paper, we establish the mathematical framework of a novel imaging technique, namely photo-magnetic imaging (PMI). PMI uses a laser to illuminate biological tissues and measure the induced temperature variations using magnetic resonance imaging (MRI). PMI overcomes the limitation of conventional optical imaging and allows imaging of the optical contrast at MRI spatial resolution. The image reconstruction for PMI, using a finite-element-based algorithm with an iterative approach, is presented in this paper. The quantitative accuracy of PMI is investigated for various inclusion sizes, depths and absorption values. Then, a comparison between conventional diffuse optical tomography (DOT) and PMI is carried out to illustrate the superior performance of PMI. An example is presented showing that two 2 mm diameter inclusions embedded 4.5 mm deep and located side by side in a 25 mm diameter circular geometry medium are recovered as a single 6 mm diameter object with DOT. However, these two objects are not only effectively resolved with PMI, but their true concentrations are also recovered successfully. (paper)

  20. High temporal resolution functional MRI using parallel echo volumar imaging

    International Nuclear Information System (INIS)

    Rabrait, C.; Ciuciu, P.; Ribes, A.; Poupon, C.; Dehaine-Lambertz, G.; LeBihan, D.; Lethimonnier, F.; Le Roux, P.; Dehaine-Lambertz, G.

    2008-01-01

    Purpose: To combine parallel imaging with 3D single-shot acquisition (echo volumar imaging, EVI) in order to acquire high temporal resolution volumar functional MRI (fMRI) data. Materials and Methods: An improved EVI sequence was associated with parallel acquisition and field of view reduction in order to acquire a large brain volume in 200 msec. Temporal stability and functional sensitivity were increased through optimization of all imaging parameters and Tikhonov regularization of parallel reconstruction. Two human volunteers were scanned with parallel EVI in a 1.5 T whole-body MR system, while submitted to a slow event-related auditory paradigm. Results: Thanks to parallel acquisition, the EVI volumes display a low level of geometric distortions and signal losses. After removal of low-frequency drifts and physiological artifacts,activations were detected in the temporal lobes of both volunteers and voxel-wise hemodynamic response functions (HRF) could be computed. On these HRF different habituation behaviors in response to sentence repetition could be identified. Conclusion: This work demonstrates the feasibility of high temporal resolution 3D fMRI with parallel EVI. Combined with advanced estimation tools,this acquisition method should prove useful to measure neural activity timing differences or study the nonlinearities and non-stationarities of the BOLD response. (authors)

  1. [Use of MRI before biopsy in diagnosis of prostate cancer: Single-operator study].

    Science.gov (United States)

    Bassard, S; Mege, J-L

    2015-12-01

    The diagnostic for prostate cancer is changing. To improve the detection of this cancer, urologists expect a lot from the contribution of magnetic resonance imaging (MRI). What is the role of this imaging in prostate cancer detection? This is a retrospective study, from 2011 to 2013, mono-centric and single-operator. Of the 464 needle biopsy of the prostate (BP), we excluded those with PSA>20 ng/mL or digital rectal examination (DRE)>T3. The remaining 430 BP were submitted or not to a 1.5 tesla MRI with pelvic antenna. The primary aim is the overall detection of prostate cancer. Secondary aim was the detection rate during the first series of BP and repeat BP, between the two groups in the MRI group. MRI and MRI without populations are comparable for age (63.3 vs 64.6), PSA (6.10 vs 6.13), DRE>T1c, prostate volume (55.4 cm(3) vs 51.7 cm(3)). There is no significant difference in overall detection between the two groups (P=0.12). There is no significant difference in cancer detection between the first BP (P=0.13) and the repeat BP (P=0.07). There is a significant difference in the early detection of BP MRI group (P=0.03) but not for the BP repeat MRI group (P=0.07). For 108 BP iterative MRI group, there were 67 BP targeted "mentally" with MRI: 18 cancers were detected, making a 25% detection rate. This study helps to highlight the value of MRI in the early rounds of BP but we can ask the value of this imaging during repeat biopsies. Targeted biopsies "mentally" do not have the expected detection sensitivity and seems to require a three-dimensional reconstruction to be more effective. 5. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  2. Advanced imaging techniques in pediatric body MRI

    Energy Technology Data Exchange (ETDEWEB)

    Courtier, Jesse [UCSF Benioff Children' s Hospital, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Rao, Anil G. [Medical University of South Carolina, Department of Radiology, Charleston, SC (United States); Anupindi, Sudha A. [Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States)

    2017-05-15

    While there are many challenges specific to pediatric abdomino-pelvic MRI, many recent advances are addressing these challenges. It is therefore essential for radiologists to be familiar with the latest advances in MR imaging. Laudable efforts have also recently been implemented in many centers to improve the overall experience of pediatric patients, including the use of dedicated radiology child life specialists, MRI video goggles, and improved MR suite environments. These efforts have allowed a larger number of children to be scanned while awake, with fewer studies being done under sedation or anesthesia; this has resulted in additional challenges from patient motion and difficulties with breath-holding and tolerating longer scan times. In this review, we highlight common challenges faced in imaging the pediatric abdomen and pelvis and discuss the application of the newest techniques to address these challenges. Additionally, we highlight the newest advances in quantified imaging techniques, specifically in MR liver iron quantification. The techniques described in this review are all commercially available and can be readily implemented. (orig.)

  3. PET/MRI for Oncologic Brain Imaging

    DEFF Research Database (Denmark)

    Rausch, Ivo; Rischka, Lucas; Ladefoged, Claes N

    2017-01-01

    The aim of this study was to compare attenuation-correction (AC) approaches for PET/MRI in clinical neurooncology.Methods:Forty-nine PET/MRI brain scans were included: brain tumor studies using18F-fluoro-ethyl-tyrosine (18F-FET) (n= 31) and68Ga-DOTANOC (n= 7) and studies of healthy subjects using18...... by Siemens Healthcare). As a reference, AC maps were derived from patient-specific CT images (CTref). PET data were reconstructed using standard settings after AC with all 4 AC methods. We report changes in diagnosis for all brain tumor patients and the following relative differences values (RDs...... of the whole brain and 10 anatomic regions segmented on MR images.Results:For brain tumor imaging (A and B), the standard PET-based diagnosis was not affected by any of the 3 MR-AC methods. For A, the average RDs of SUVmeanwere -10%, -4%, and -3% and of the VOIs 1%, 2%, and 7% for DIXON, UTE, and BD...

  4. Guidelines for imaging retinoblastoma: imaging principles and MRI standardization

    Energy Technology Data Exchange (ETDEWEB)

    Graaf, Pim de; Rodjan, Firazia; Castelijns, Jonas A. [VU University Medical Center, Department of Radiology, Amsterdam (Netherlands); Goericke, Sophia [University Hospital, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Galluzzi, Paolo [Azienda Ospedaliera e Universitaria Senese, Policlinico ' ' Le Scotte' ' , Unit of Diagnostic and Therapeutic Neuroradiology, Siena (Italy); Maeder, Philippe [CHUV, Service de Radiodiagnostic et Radiologie Interventionelle, Lausanne (Switzerland); Brisse, Herve J. [Institut Curie, Departement d' Imagerie, Paris (France)

    2012-01-15

    Retinoblastoma is the most common intraocular tumor in children. The diagnosis is usually established by the ophthalmologist on the basis of fundoscopy and US. Together with US, high-resolution MRI has emerged as an important imaging modality for pretreatment assessment, i.e. for diagnostic confirmation, detection of local tumor extent, detection of associated developmental malformation of the brain and detection of associated intracranial primitive neuroectodermal tumor (trilateral retinoblastoma). Minimum requirements for pretreatment diagnostic evaluation of retinoblastoma or mimicking lesions are presented, based on consensus among members of the European Retinoblastoma Imaging Collaboration (ERIC). The most appropriate techniques for imaging in a child with leukocoria are reviewed. CT is no longer recommended. Implementation of a standardized MRI protocol for retinoblastoma in clinical practice may benefit children worldwide, especially those with hereditary retinoblastoma, since a decreased use of CT reduces the exposure to ionizing radiation. (orig.)

  5. Diagnosis of magnetic resonance imaging (MRI) for blowout fracture. Three advantages of MRI

    International Nuclear Information System (INIS)

    Nishida, Yasuhiro; Aoki, Yoshiko; Hayashi, Osamu; Kimura, Makiko; Murata, Toyotaka; Ishida, Youichi; Iwami, Tatsuya; Kani, Kazutaka

    1999-01-01

    Magnetic resonance imaging (MRI) gives a much more detailed picture of the soft tissue than computerized tomography (CT). In blowout fracture cases, it is very easy to observe the incarcerated orbital tissue. We performed MRI in 19 blowout fracture cases. After evaluating the images, we found three advantages of MRI. The first is that even small herniation of the orbital contents can easily be detected because the orbital fatty tissue contrasts well around the other tissues in MRI. The second is that the incarcerated tissues can be clearly differentiated because a clear contrast between the orbital fatty tissue and the extraocular muscle can be seen in MRI. The third is that the running images of the incarcerated muscle belly can be observed because any necessary directional slies can be taken in MRI. These advantages are very important in the diagnosis of blowout fractures. MRI should be employed in blowout fracture cases in addition to CT. (author)

  6. Indications for fetal magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Prayer, D.

    2006-01-01

    Indications to perform fetal magnetic resonance imaging (MRI) are composed of common ones related to methodological problems of ultrasound (US) assessment (such as for instance hydramnios) and special ones. The latter are related to MR capability of high-resolution soft tissue contrast and an extended field of view that allows visualization of the whole fetus, even in later stages of pregnancy. The most important indications include confirmation of US findings, work-up of malformations with respect to individual prognosis and genetic background, differentiation between acquired conditions and malformations, visualization of pathologies that have to be treated surgically immediately after birth, and morphological changes of the placenta. (orig.) [de

  7. Hemorrhage detection in MRI brain images using images features

    Science.gov (United States)

    Moraru, Luminita; Moldovanu, Simona; Bibicu, Dorin; Stratulat (Visan), Mirela

    2013-11-01

    The abnormalities appear frequently on Magnetic Resonance Images (MRI) of brain in elderly patients presenting either stroke or cognitive impairment. Detection of brain hemorrhage lesions in MRI is an important but very time-consuming task. This research aims to develop a method to extract brain tissue features from T2-weighted MR images of the brain using a selection of the most valuable texture features in order to discriminate between normal and affected areas of the brain. Due to textural similarity between normal and affected areas in brain MR images these operation are very challenging. A trauma may cause microstructural changes, which are not necessarily perceptible by visual inspection, but they could be detected by using a texture analysis. The proposed analysis is developed in five steps: i) in the pre-processing step: the de-noising operation is performed using the Daubechies wavelets; ii) the original images were transformed in image features using the first order descriptors; iii) the regions of interest (ROIs) were cropped from images feature following up the axial symmetry properties with respect to the mid - sagittal plan; iv) the variation in the measurement of features was quantified using the two descriptors of the co-occurrence matrix, namely energy and homogeneity; v) finally, the meaningful of the image features is analyzed by using the t-test method. P-value has been applied to the pair of features in order to measure they efficacy.

  8. PET-MRI: the likely future of molecular imaging

    International Nuclear Information System (INIS)

    Chen Xiang; Zhao Jinhua; Zhao Jun

    2008-01-01

    PET-CT is a successful combination of functional and morphologic information, and it has already been shown to have great value both in clinics and in scientific research. MRI is another kind of morphologic imaging method, in contrast to CT, MRI can yield images with higher soft-tissue contrast and better spatial resolution. The combination of PET and MRI for simultaneous data acquisition should have far- reaching consequences for molecular imaging. This review will talk about the problems met in the development of PET-MRI and describe the progress to date and look forward to its potential application. (authors)

  9. Electromagnetic considerations for RF current density imaging [MRI technique].

    Science.gov (United States)

    Scott, G C; Joy, M G; Armstrong, R L; Henkelman, R M

    1995-01-01

    Radio frequency current density imaging (RF-CDI) is a recent MRI technique that can image a Larmor frequency current density component parallel to B(0). Because the feasibility of the technique was demonstrated only for homogeneous media, the authors' goal here is to clarify the electromagnetic assumptions and field theory to allow imaging RF currents in heterogeneous media. The complete RF field and current density imaging problem is posed. General solutions are given for measuring lab frame magnetic fields from the rotating frame magnetic field measurements. For the general case of elliptically polarized fields, in which current and magnetic field components are not in phase, one can obtain a modified single rotation approximation. Sufficient information exists to image the amplitude and phase of the RF current density parallel to B(0) if the partial derivative in the B(0) direction of the RF magnetic field (amplitude and phase) parallel to B(0) is much smaller than the corresponding current density component. The heterogeneous extension was verified by imaging conduction and displacement currents in a phantom containing saline and pure water compartments. Finally, the issues required to image eddy currents are presented. Eddy currents within a sample will distort both the transmitter coil reference system, and create measurable rotating frame magnetic fields. However, a three-dimensional electro-magnetic analysis will be required to determine how the reference system distortion affects computed eddy current images.

  10. Recent topics in NMR imaging and MRI

    International Nuclear Information System (INIS)

    Watanabe, Tokuko

    2002-01-01

    NMR and NMR imaging (MRI) are finding increasing use not only in the clinical and medical fields, but also in material, physicochemical, biological, geological, industrial and environmental applications. This short review is limited to two topics: new techniques and pulse sequences and their application to non-clinical fields that may have clinical application; and new trends in MR contrast agents. The former topic addresses pulse sequence and data analysis; dynamics such as diffusion, flow, velocity and velocimetry; chemometrics; pharmacological agents; and chemotherapy; the latter topic addresses contrast agents (CA) sensitive to biochemical activity; CA based on water exchange; molecular interactions and stability of CA; characteristics of emerging CA; superparamagnetic CA; and macromolecular CA. (author)

  11. Testing competing hypotheses about single trial fMRI

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Purushotham, Archana; Kim, Seong-Ge

    2002-01-01

    We use a Bayesian framework to compute probabilities of competing hypotheses about functional activation based on single trial fMRI measurements. Within the framework we obtain a complete probabilistic picture of competing hypotheses, hence control of both type I and type II errors....

  12. Optimized workflow and imaging protocols for whole-body oncologic PET/MRI.

    Science.gov (United States)

    Ishii, Shirou; Hara, Takamitsu; Nanbu, Takeyuki; Suenaga, Hiroki; Sugawara, Shigeyasu; Kuroiwa, Daichi; Sekino, Hirofumi; Miyajima, Masayuki; Kubo, Hitoshi; Oriuchi, Noboru; Ito, Hiroshi

    2016-11-01

    Although PET/MRI has the advantages of a simultaneous acquisition of PET and MRI, high soft-tissue contrast of the MRI images, and reduction of radiation exposure, its low profitability and long acquisition time are significant problems in clinical settings. Thus, MRI protocols that meet oncological purposes need to be used in order to reduce examination time while securing detectability. Currently, half-Fourier acquisition single-shot turbo spin echo and 3D-T1 volumetric interpolated breath-hold examination may be the most commonly used sequences for whole-body imaging due to their shorter acquisition time and higher diagnostic accuracy. Although there have been several reports that adding diffusion weighted image (DWI) to PET/MRI protocol has had no effect on tumor detection to date, in cases of liver, kidney, bladder, and prostate cancer, the use of DWI may be beneficial in detecting lesions. Another possible option is to scan each region with different MRI sequences instead of scanning the whole body using one sequence continuously. We herein report a workflow and imaging protocols for whole-body oncologic PET/MRI using an integrated system in the clinical routine, designed for the detection, for example by cancer screening, of metastatic lesions, in order to help future users optimize their workflow and imaging protocols.

  13. Magnetic resonance imaging (MRI) and relaxation time mapping of concrete

    Science.gov (United States)

    Beyea, Steven Donald

    2001-07-01

    The use of Magnetic Resonance Imaging (MRI) of water in concrete is presented. This thesis will approach the problem of MR imaging of concrete by attempting to design new methods, suited to concrete materials, rather than attempting to force the material to suit the method. A number of techniques were developed, which allow the spatial observation of water in concrete in up to three dimensions, and permits the determination of space resolved moisture content, as well as local NMR relaxation times. These methods are all based on the Single-Point Imaging (SPI) method. The development of these new methods will be described, and the techniques validated using phantom studies. The study of one-dimensional moisture transport in drying concrete was performed using SPI. This work examined the effect of initial mixture proportions and hydration time on the drying behaviour of concrete, over a period of three months. Studies of drying concrete were also performed using spatial mapping of the spin-lattice (T1) and effective spin-spin (T2*) relaxation times, thereby permitting the observation of changes in the water occupied pore surface-to-volume ratio (S/V) as a function of drying. Results of this work demonstrated changes in the S/V due to drying, hydration and drying induced microcracking. Three-dimensional MRI of concrete was performed using SPRITE (Single-Point Ramped Imaging with T1 Enhancement) and turboSPI (turbo Single Point Imaging). While SPRITE allows for weighting of MR images using T 1 and T2*, turboSPI allows T2 weighting of the resulting images. Using relaxation weighting it was shown to be possible to discriminate between water contained within a hydrated cement matrix, and water in highly porous aggregates, used to produce low-density concrete. Three dimensional experiments performed using SPRITE and turboSPI examined the role of self-dessication, drying, initial aggregate saturation and initial mixture conditions on the transport of moisture between porous

  14. Imaging tools to study pharmacology: functional MRI on small rodents

    Directory of Open Access Journals (Sweden)

    Elisabeth eJonckers

    2015-10-01

    Full Text Available Functional Magnetic Resonance Imaging (fMRI is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD fMRI techniques, including resting state (rsfMRI, stimulus-evoked (st-fMRI, and pharmacological MRI (phMRI. Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimulation and/or a pharmacological challenge. The first part of this review describes the physiological basis of BOLD fMRI and the hemodynamic response on which the MRI contrast is based. Specific emphasis goes to possible effects of anaesthesia and the animal’s physiological conditions on neural activity and the hemodynamic response. The second part of this review describes applications of the aforementioned techniques in pharmacologically-induced, as well as in traumatic and transgenic disease models and illustrates how multiple fMRI methods can be applied successfully to evaluate different aspects of a specific disorder. For example, fMRI techniques can be used to pinpoint the neural substrate of a disease beyond previously defined hypothesis-driven regions-of-interest (ROIs. In addition, fMRI techniques allow one to dissect how specific modifications (e.g. treatment, lesion etc. modulate the functioning of specific brain areas (st-fMRI, phMRI and how functional connectivity (rsfMRI between several brain regions is affected, both in acute and extended time frames. Furthermore, fMRI techniques can be used to assess/explore the efficacy of novel treatments in depth, both in fundamental research as well as in preclinical settings. In conclusion, by describing several exemplary studies, we aim to highlight the advantages of functional MRI in exploring the acute and long-term effects of pharmacological substances and/or pathology on brain functioning along with

  15. Heart MRI

    Science.gov (United States)

    Magnetic resonance imaging - cardiac; Magnetic resonance imaging - heart; Nuclear magnetic resonance - cardiac; NMR - cardiac; MRI of the heart; Cardiomyopathy - MRI; Heart failure - MRI; Congenital heart disease - MRI

  16. MRI

    Science.gov (United States)

    ... the room. Pins, hairpins, metal zippers, and similar metallic items can distort the images. Removable dental work ... an MRI can cause heart pacemakers and other implants not to work as well. The magnets can ...

  17. Visualization of pulmonary nodules with magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Plathow, C.; Deutsches Krebsforschungszentrum; Meinzer, H.-P.; Kauczor, H.-U.

    2006-01-01

    Visualization of pulmonary nodules using magnetic resonance imaging (MRI) plays a minor role compared with computed tomography (CT). Technical developments made it possible to apply MRI more and more frequently in functional imaging. Imaging of the motion of pulmonary nodules during respiration, e.g., to optimize high precision therapy techniques, is a new field of research. This paper describes developments in analysis and visualization of pulmonary nodules during respiration using MRI. Besides actual 2D techniques new 3D techniques to quantify motion of pulmonary nodules during respiration are presented. (orig.) [de

  18. PET/MRI in Oncological Imaging: State of the Art

    Science.gov (United States)

    Bashir, Usman; Mallia, Andrew; Stirling, James; Joemon, John; MacKewn, Jane; Charles-Edwards, Geoff; Goh, Vicky; Cook, Gary J.

    2015-01-01

    Positron emission tomography (PET) combined with magnetic resonance imaging (MRI) is a hybrid technology which has recently gained interest as a potential cancer imaging tool. Compared with CT, MRI is advantageous due to its lack of ionizing radiation, superior soft-tissue contrast resolution, and wider range of acquisition sequences. Several studies have shown PET/MRI to be equivalent to PET/CT in most oncological applications, possibly superior in certain body parts, e.g., head and neck, pelvis, and in certain situations, e.g., cancer recurrence. This review will update the readers on recent advances in PET/MRI technology and review key literature, while highlighting the strengths and weaknesses of PET/MRI in cancer imaging. PMID:26854157

  19. PET/MRI in Oncological Imaging: State of the Art

    Directory of Open Access Journals (Sweden)

    Usman Bashir

    2015-07-01

    Full Text Available Positron emission tomography (PET combined with magnetic resonance imaging (MRI is a hybrid technology which has recently gained interest as a potential cancer imaging tool. Compared with CT, MRI is advantageous due to its lack of ionizing radiation, superior soft-tissue contrast resolution, and wider range of acquisition sequences. Several studies have shown PET/MRI to be equivalent to PET/CT in most oncological applications, possibly superior in certain body parts, e.g., head and neck, pelvis, and in certain situations, e.g., cancer recurrence. This review will update the readers on recent advances in PET/MRI technology and review key literature, while highlighting the strengths and weaknesses of PET/MRI in cancer imaging.

  20. MRI, CT and TRUS imaging of seminal vesicle metastasis

    International Nuclear Information System (INIS)

    Larsson, P.; Blomqvist, L.; Norming, U.

    1997-01-01

    We present a case of a testicular germ-cell metastasis in the seminal vesicle. Diagnostic imaging with transrectal ultrasonography (TRUS), CT, and MRI was performed. This case emphasizes the role of MRI in the evaluation of patients with pathology in the pelvic region. (orig.)

  1. Clinically relevant magnetic resonance imaging (MRI) findings in ...

    African Journals Online (AJOL)

    Background: Shoulder pain is the most common and well-documented site of musculoskeletal pain in elite swimmers. Structural abnormalities on magnetic resonance imaging (MRI) of elite swimmers' symptomatic shoulders are common. Little has been documented about the association between MRI findings in the ...

  2. Muscle contraction analysis with MRI image

    International Nuclear Information System (INIS)

    Horio, Hideyuki; Kuroda, Yoshihiro; Imura, Masataka; Oshiro, Osamu

    2010-01-01

    The MRI measurement has been widely used from the advantage such as no radiation exposure and high resolution. In various measurement objects, the muscle is used for a research and clinical practice. But it was difficult to judge static state of a muscle contraction. In this study, we focused on a proton density change by the blood vessel pressure at the time of the muscle contraction, and aimed the judgments of muscle contraction from variance of the signal intensity. First, the background was removed from the measured images. Second, each signal divided into the low signal side and the high signal side, and variance values (σ H , σ L ) and the ratio (μ) were calculated. Finally, Relax and strain state ware judged from the ratio (μ). As a Result, in relax state, ratio (μ r ) was 0.9823±0.06133. And in strain state, ratio (μ s ) was 0.7547±0.10824. Therefore, a significant difference was obtained in relax state and strain state. Therefore, the strain state judgment of the muscle was possible by this study's method. (author)

  3. Functional imaging of the kidneys with fast MRI techniques

    International Nuclear Information System (INIS)

    Prasad, Pottumarthi V.; Priatna, Agus

    1999-01-01

    Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible

  4. EPOXI EARTH OBS - MRI CALIBRATED IMAGES V2.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset contains calibrated, 750-nm filter images of Earth acquired by the Deep Impact Medium Resolution Visible CCD (MRI) during the EPOCh and Cruise 2 phases...

  5. MRI of persistent cloaca: Can it substitute conventional imaging?

    Energy Technology Data Exchange (ETDEWEB)

    Mohammad, Shaimaa Abdelsattar, E-mail: shaimaa96@hotmail.com [Department of Radiodiagnosis, Faculty of Medicine, Ain-Shams University (Egypt); AbouZeid, Amr Abdelhamid, E-mail: amrabdelhamid@hotmail.com [Department of Pediatric Surgery, Faculty of Medicine, Ain-Shams University (Egypt)

    2013-02-15

    Purpose: To define the role of MRI in the preoperative assessment of patients with persistent cloaca and whether it can substitute other imaging modalities. Methods: We prospectively examined eleven patients with persistent cloaca between July 2007 and March 2012. Non contrast MRI examinations were performed on 1.5 T magnet using head coil. Multiple pulse sequences (T1WI, T2WI, fat suppression) were obtained in axial, sagittal and coronal planes of the pelvis, abdomen, and spine. The scans were reviewed for the following: the level and type of rectal termination, the developmental state of striated muscle complex (SMC), associated genitourinary and spinal anomalies. MRI findings were compared to conventional fluoroscopic imaging, operative and endoscopic findings. We applied novel MRI parameters (urethral length, relative hiatal distance and vaginal volume). The relation between different parameters was tested statistically using Pearson correlation test. Results: MRI could accurately demonstrate the level of bowel termination in patients with persistent cloaca, in addition to its high sensitivity for detection of mullerian anomalies which were present in 73% of patients. Furthermore, MRI could disclose associating renal and spinal anomalies, and assess the developmental state of SMC. The shorter the urethra (higher urogenital confluence), the narrower the pelvic hiatus, and the more was the obstruction (vaginal distension). Conclusion: MRI is a valuable tool in exploring the different internal anatomical features of the cloacal anomaly; and when combined with endoscopy, MRI can make other preoperative conventional imaging unnecessary.

  6. A comparative study of single and multiple hand tasks using functional MRI

    International Nuclear Information System (INIS)

    Shin, Byung Suck; Lee, Ho Kyu; Park, Sung Tae; Kim, Dong Eun; Lee, Myung Jun; Choi, Choong Gon; Kim, Jae Kyun; Suh, Dae Chul; Lim, Tae Hwan

    1998-01-01

    The purpose of this study is to assess, using functional MRI and by comparing activated motor sensory areas, the independence of brain activation during single and alternative multiple hand tasks. The subjects were six healthy volunteers. Using at 1.5T Siemens system and single shot FID-EPI sequencing (T2 weighted image; TR/TE 0.96 msec/ 61msec, flip angle 90 deg, matrix size 96 x 128, slice thickness/gap 5 mm/0.8 mm, FOV 200 mm) and T1-weighted anatomic images, functional MRI was performed. The paradigm of motor tasks consisted of appositional finger movements; the first involved the separate use of the right, left, and both hands in sequence. Using cross-correlation method (threshold : 0.6) and fMRI analysis software (stimulate 5.0), functional images were obtained. The activated area of brain cortex, the number of pixel, the average percentage change in signal intensity, and correlation of the time-signal intensity curve in the activated motor area were analysed and compared between the two task groups. Statistical analysis involved the use of Wilcoxon signed-rank test. Brain activation did not differ according to whether the motor task was single or alternative. We therefore suggest that during multiple stimuli, the relevant functional area and neuronal column are activated independently. (author). 19 refs., 2 tabs., 3 figs

  7. Volumetric BOLD fMRI simulation: from neurovascular coupling to multivoxel imaging

    International Nuclear Information System (INIS)

    Chen, Zikuan; Calhoun, Vince

    2012-01-01

    The blood oxygenation-level dependent (BOLD) functional magnetic resonance imaging (fMRI) modality has been numerically simulated by calculating single voxel signals. However, the observation on single voxel signals cannot provide information regarding the spatial distribution of the signals. Specifically, a single BOLD voxel signal simulation cannot answer the fundamental question: is the magnetic resonance (MR) image a replica of its underling magnetic susceptibility source? In this paper, we address this problem by proposing a multivoxel volumetric BOLD fMRI simulation model and a susceptibility expression formula for linear neurovascular coupling process, that allow us to examine the BOLD fMRI procedure from neurovascular coupling to MR image formation. Since MRI technology only senses the magnetism property, we represent a linear neurovascular-coupled BOLD state by a magnetic susceptibility expression formula, which accounts for the parameters of cortical vasculature, intravascular blood oxygenation level, and local neuroactivity. Upon the susceptibility expression of a BOLD state, we carry out volumetric BOLD fMRI simulation by calculating the fieldmap (established by susceptibility magnetization) and the complex multivoxel MR image (by intravoxel dephasing). Given the predefined susceptibility source and the calculated complex MR image, we compare the MR magnitude (phase, respectively) image with the predefined susceptibility source (the calculated fieldmap) by spatial correlation. The spatial correlation between the MR magnitude image and the magnetic susceptibility source is about 0.90 for the settings of T E = 30 ms, B 0 = 3 T, voxel size = 100 micron, vessel radius = 3 micron, and blood volume fraction = 2%. Using these parameters value, the spatial correlation between the MR phase image and the susceptibility-induced fieldmap is close to 1.00. Our simulation results show that the MR magnitude image is not an exact replica of the magnetic susceptibility

  8. Image processing techniques for quantification and assessment of brain MRI

    NARCIS (Netherlands)

    Kuijf, H.J.

    2013-01-01

    Magnetic resonance imaging (MRI) is a widely used technique to acquire digital images of the human brain. A variety of acquisition protocols is available to generate images in vivo and noninvasively, giving great opportunities to study the anatomy and physiology of the human brain. In my thesis,

  9. Labeling of mesenchymal stem cells for MRI with single-cell sensitivity

    Directory of Open Access Journals (Sweden)

    Ariza de Schellenberger A

    2016-04-01

    Full Text Available Angela Ariza de Schellenberger,1 Harald Kratz,1 Tracy D Farr,2,3 Norbert Löwa,4 Ralf Hauptmann,1 Susanne Wagner,1 Matthias Taupitz,1 Jörg Schnorr,1 Eyk A Schellenberger1 1Department of Radiology, 2Department of Experimental Neurology, Center for Stroke Research Berlin, Charité – Universitätsmedizin Berlin, Berlin, Germany; 3School of Life Sciences, University of Nottingham, Medical School, Nottingham, UK; 4Department of Biomagnetic Signals, Physikalisch-Technische Bundesanstalt Berlin, Berlin, Germany Abstract: Sensitive cell detection by magnetic resonance imaging (MRI is an important tool for the development of cell therapies. However, clinically approved contrast agents that allow single-cell detection are currently not available. Therefore, we compared very small iron oxide nanoparticles (VSOP and new multicore carboxymethyl dextran-coated iron oxide nanoparticles (multicore particles, MCP designed by our department for magnetic particle imaging (MPI with discontinued Resovist® regarding their suitability for detection of single mesenchymal stem cells (MSC by MRI. We achieved an average intracellular nanoparticle (NP load of >10 pg Fe per cell without the use of transfection agents. NP loading did not lead to significantly different results in proliferation, colony formation, and multilineage in vitro differentiation assays in comparison to controls. MRI allowed single-cell detection using VSOP, MCP, and Resovist® in conjunction with high-resolution T2*-weighted imaging at 7 T with postprocessing of phase images in agarose cell phantoms and in vivo after delivery of 2,000 NP-labeled MSC into mouse brains via the left carotid artery. With optimized labeling conditions, a detection rate of ~45% was achieved; however, the experiments were limited by nonhomogeneous NP loading of the MSC population. Attempts should be made to achieve better cell separation for homogeneous NP loading and to thus improve NP

  10. TH-A-BRF-11: Image Intensity Non-Uniformities Between MRI Simulation and Diagnostic MRI

    International Nuclear Information System (INIS)

    Paulson, E

    2014-01-01

    Purpose: MRI simulation for MRI-based radiotherapy demands that patients be setup in treatment position, which frequently involves use of alternative radiofrequency (RF) coil configurations to accommodate immobilized patients. However, alternative RF coil geometries may exacerbate image intensity non-uniformities (IINU) beyond those observed in diagnostic MRI, which may challenge image segmentation and registration accuracy as well as confound studies assessing radiotherapy response when MR simulation images are used as baselines for evaluation. The goal of this work was to determine whether differences in IINU exist between MR simulation and diagnostic MR images. Methods: ACR-MRI phantom images were acquired at 3T using a spin-echo sequence (TE/TR:20/500ms, rBW:62.5kHz, TH/skip:5/5mm). MR simulation images were obtained by wrapping two flexible phased-array RF coils around the phantom. Diagnostic MR images were obtained by placing the phantom into a commercial phased-array head coil. Pre-scan normalization was enabled in both cases. Images were transferred offline and corrected for IINU using the MNI N3 algorithm. Coefficients of variation (CV=σ/μ) were calculated for each slice. Wilcoxon matched-pairs and Mann-Whitney tests compared CV values between original and N3 images and between MR simulation and diagnostic MR images. Results: Significant differences in CV were detected between original and N3 images in both MRI simulation and diagnostic MRI groups (p=0.010, p=0.010). In addition, significant differences in CV were detected between original MR simulation and original and N3 diagnostic MR images (p=0.0256, p=0.0016). However, no significant differences in CV were detected between N3 MR simulation images and original or N3 diagnostic MR images, demonstrating the importance of correcting MR simulation images beyond pre-scan normalization prior to use in radiotherapy. Conclusions: Alternative RF coil configurations used in MRI simulation can Result in

  11. MRI

    DEFF Research Database (Denmark)

    Schroeter, Aileen; Rudin, Markus; Gianolio, Eliana

    2017-01-01

    This chapter discusses principles of nuclear magnetic resonance (NMR) and MRI followed by a survey on the major classes of MRI contrast agents (CA), their modes of action, and some of the most significative applications. The two more established classes of MRI-CA are represented by paramagnetic...... been attained that markedly increase the number and typology of systems with CEST properties. Currently much attention is also devoted to hyperpolarized molecules that display a sensitivity enhancement sufficient for their direct exploitation for the formation of the MR image. A real breakthrough...

  12. CT and MRI techniques for imaging around orthopedic hardware

    Energy Technology Data Exchange (ETDEWEB)

    Do, Thuy Duong; Skornitzke, Stephan; Weber, Marc-Andre [Heidelberg Univ. (Germany). Dept. of Clinical Radiology; Sutter, Reto [Uniklinik Balgrist, Zurich (Switzerland). Radiology

    2018-01-15

    Orthopedic hardware impairs image quality in cross-sectional imaging. With an increasing number of orthopedic implants in an aging population, the need to mitigate metal artifacts in computed tomography and magnetic resonance imaging is becoming increasingly relevant. This review provides an overview of the major artifacts in CT and MRI and state-of-the-art solutions to improve image quality. All steps of image acquisition from device selection, scan preparations and parameters to image post-processing influence the magnitude of metal artifacts. Technological advances like dual-energy CT with the possibility of virtual monochromatic imaging (VMI) and new materials offer opportunities to further reduce artifacts in CT and MRI. Dedicated metal artifact reduction sequences contain algorithms to reduce artifacts and improve imaging of surrounding tissue and are essential tools in orthopedic imaging to detect postoperative complications in early stages.

  13. Multi-modal image registration: matching MRI with histology

    Science.gov (United States)

    Alic, Lejla; Haeck, Joost C.; Klein, Stefan; Bol, Karin; van Tiel, Sandra T.; Wielopolski, Piotr A.; Bijster, Magda; Niessen, Wiro J.; Bernsen, Monique; Veenland, Jifke F.; de Jong, Marion

    2010-03-01

    Spatial correspondence between histology and multi sequence MRI can provide information about the capabilities of non-invasive imaging to characterize cancerous tissue. However, shrinkage and deformation occurring during the excision of the tumor and the histological processing complicate the co registration of MR images with histological sections. This work proposes a methodology to establish a detailed 3D relation between histology sections and in vivo MRI tumor data. The key features of the methodology are a very dense histological sampling (up to 100 histology slices per tumor), mutual information based non-rigid B-spline registration, the utilization of the whole 3D data sets, and the exploitation of an intermediate ex vivo MRI. In this proof of concept paper, the methodology was applied to one tumor. We found that, after registration, the visual alignment of tumor borders and internal structures was fairly accurate. Utilizing the intermediate ex vivo MRI, it was possible to account for changes caused by the excision of the tumor: we observed a tumor expansion of 20%. Also the effects of fixation, dehydration and histological sectioning could be determined: 26% shrinkage of the tumor was found. The annotation of viable tissue, performed in histology and transformed to the in vivo MRI, matched clearly with high intensity regions in MRI. With this methodology, histological annotation can be directly related to the corresponding in vivo MRI. This is a vital step for the evaluation of the feasibility of multi-spectral MRI to depict histological groundtruth.

  14. Magnetic resonance imaging (MRI) of an intraventricular hemorrhage

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Ryungchan; Higashi, Tooru; Ito, Shotaro; Kadoya, Satoru; Takarada, Akira; Sato, Shuji; Kurauchi, Manabu.

    1987-08-01

    The utility of MRI was investigated in 10 patients with intraventricular hemorrhage. MRI was found to be, in many respects, superior to CT: 1) MRI is able to detect to some extent the aging of an intraventricular hematoma. 2) It can determine the character of intraventricular cerebrospinal fluid, whether it is normal, bloody, or hyperprotein. 3) It can detect the cause of hemorrhage in the case of arterio-venous malformation. 4) MRI permits the detection of the penetration course and the location of a ventricular hematoma. 5) It can clearly detect periventricular lesions of early-stage hydrocephalus, accompanied by increased intracranial pressure and followed by intraventricular hemorrhage, by imaging the periventricular high-signal-intensity area. 6) MRI can clearly diagnose complications of intracranial lesions. For instance, it can distinguish subdural fluid collection from chronic subdural hematoma and can detect whether a cerebral infarction is new or old. On the other hand, MRI also has some disadvantages: 1) The imaging time is long, and clinical application is difficult, in serious and/or infant cases. 2) It is impossible to use MRI in some patients who have magnetic material in their bodies. 3) The spatial-image resolution is not good.

  15. Fusion of PET and MRI for Hybrid Imaging

    Science.gov (United States)

    Cho, Zang-Hee; Son, Young-Don; Kim, Young-Bo; Yoo, Seung-Schik

    Recently, the development of the fusion PET-MRI system has been actively studied to meet the increasing demand for integrated molecular and anatomical imaging. MRI can provide detailed anatomical information on the brain, such as the locations of gray and white matter, blood vessels, axonal tracts with high resolution, while PET can measure molecular and genetic information, such as glucose metabolism, neurotransmitter-neuroreceptor binding and affinity, protein-protein interactions, and gene trafficking among biological tissues. State-of-the-art MRI systems, such as the 7.0 T whole-body MRI, now can visualize super-fine structures including neuronal bundles in the pons, fine blood vessels (such as lenticulostriate arteries) without invasive contrast agents, in vivo hippocampal substructures, and substantia nigra with excellent image contrast. High-resolution PET, known as High-Resolution Research Tomograph (HRRT), is a brain-dedicated system capable of imaging minute changes of chemicals, such as neurotransmitters and -receptors, with high spatial resolution and sensitivity. The synergistic power of the two, i.e., ultra high-resolution anatomical information offered by a 7.0 T MRI system combined with the high-sensitivity molecular information offered by HRRT-PET, will significantly elevate the level of our current understanding of the human brain, one of the most delicate, complex, and mysterious biological organs. This chapter introduces MRI, PET, and PET-MRI fusion system, and its algorithms are discussed in detail.

  16. Safety recommendations in magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Nikolaou, K.I.; Plataniotis, T.N; Syrgiamiotis, G.V.; Dousi, M.; Panou, T.; Georgiadis, K.; Bougias, C.

    2008-01-01

    Full text: In order to discuss the long-term biological effects of MRI in the radiological department, all the components of the acquisition process must be considered. Those elements include: the main magnetic field, time varying magnetic fields and radio-frequency fields (RF). Also must be referred other types of hazards obtained by the utilization of contrast materials as gadolinium or pregnancy. The primary concern with the static magnetic field is the possibility of potential biological effects. The majority of studies show no effects on cell growth and morphology at field strengths below 2T. Data accumulated by the National Institute for Occupational Safety, the World Health Organization, and the US State Department, show no evidence of leukemia or other carcinogenesis. The secondary concern of the effects of the main magnetic field is the hazards associated with the sitting of MR systems. The static magnetic field has no respect for the confines of conventional walls, floors or ceilings. Some reversible effects have been noted on Electrocardiogram gating (ECG) at these field strengths. An increase in the amplitude of the T-wave can be noted on an ECG due to the magnetohydrodynamic effect. This is produced when a conductive fluid, such as blood, moves across a magnetic field. Some reversible biological effects including fatigue, headaches, hypotension and accounts of irritability have been observed on human subjects exposed to 2T and above. As yet, there are no known biological effects of MRI on fetuses. Also MR facilities have established individual guidelines for pregnant employees in the MR environment. Ferromagnetic metal objects can become airborne as projectiles in the presence of a strong static magnetic field. Metallic implants pose serious effects which include torque, heating and artifacts on MR images.There have been a large number of studies performed on the biological effects from Time-varying magnetic field (TVMF), since they exist around power

  17. Magnetic resonance imaging (MRI) of congenital cardiovascular malformations

    International Nuclear Information System (INIS)

    Sakakibara, Makoto; Kobayashi, Shirou; Imai, Hitoshi; Watanabe, Shigeru; Masuda, Yoshiaki; Inagaki, Yoshiaki; Morita, Huminori; Uematsu, Sadao; Arimizu, Noboru

    1986-01-01

    In order to determine the value of MRI in diagnosing congenital cardiovascular malformations, MR Images were obtained in 25 adult patients with congenital cardiovascular malformations. Gated MRI detected all of 13 atrial septal defects, and all of 4 ventricular septal defects, but ungated MRI detected none of 3 atrial septal defects. Other congenital cardiovascular malformations (2 with Ebstein's disease, 1 with Fallot's pentalogy, and 1 with Pulmonary stenosis) were well visualized. Vascular malformations (1 with Patent ducts arteriosus, 1 with Supravalvelar aortic stenosis, 1 with Coarctation of Aorta, 1 with Right Aortic Arch) were well visualized in all of 7 patients by ungated MRI. MRI was a valuable noninvasive method of diagnosing congenital heart disease. (author)

  18. Making the most of the imaging we have: using head MRI to estimate body composition

    International Nuclear Information System (INIS)

    Lack, C.M.; Lesser, G.J.; Umesi, U.N.; Bowns, J.; Chen, M.Y.; Case, D.; Hightower, R.C.; Johnson, A.J.

    2016-01-01

    Aim: To investigate the use of clinical head magnetic resonance imaging (MRI) in determining body composition and to evaluate how well it correlates with established measures based on abdominal computed tomography (CT). Materials and methods: Ninety-nine consecutive patients were identified who had undergone both brain MRI and abdominal CT within a 2-week span. Volumes of fat and muscle in the extracranial head were measured utilising several techniques by both abdominal CT and head MRI. Results: MRI-based total fat volumes in the head correlated with CT-based measurements of fat in the abdomen using both single-section (r=0.64, p<0.01) and multisection (r=0.60, p<0.01) techniques. No significant correlation was found between muscle volumes in the abdomen and head. Conclusion: Based on the present results, head MRI-based measures may provide a useful surrogate for CT measurements of abdominal fat, particularly in patients with neurological cancers, as head MRI (and not abdominal CT) is routinely and repeatedly obtained for the purpose of clinical care for these patients. - Highlights: • We compared body composition using brain MRI with previously proven abdominal CT. • Fat and muscle volumes of the extracranial compartment can be measured by MRI. • Muscle volume in the face does not correlate with abdominal muscle volume. • Fat volume in the face can be used as a surrogate for abdominal fat volume.

  19. Is the Number of Different MRI Findings More Strongly Associated with Low Back Pain Than Single MRI Findings?

    DEFF Research Database (Denmark)

    Hancock, Mark J; Kjaer, Per; Kent, Peter

    2017-01-01

    STUDY DESIGN: A cross-sectional and longitudinal analysis using 2 different data sets OBJECTIVE.: To investigate if the number of different MRI findings present is more strongly associated with low back pain (LBP) than single MRI findings. SUMMARY OF BACKGROUND DATA: Most previous studies have....... The outcome for the cross-sectional study was presence of LBP during the last year. The outcome for the longitudinal study was days to recurrence of activity limiting LBP. In both data sets we created an aggregate score of the number of different MRI findings present in each individual and assessed...... investigated the associations between single MRI findings and back pain rather than investigating combinations of MRI findings. If different individuals have different pathoanatomic sources contributing to their pain, then combinations of MRI findings may be more strongly associated with LBP. METHODS...

  20. Magnetic resonance imaging (MRI) of the renal sinus.

    Science.gov (United States)

    Krishna, Satheesh; Schieda, Nicola; Flood, Trevor A; Shanbhogue, Alampady Krishna; Ramanathan, Subramaniyan; Siegelman, Evan

    2018-04-09

    This article presents methods to improve MR imaging approach of disorders of the renal sinus which are relatively uncommon and can be technically challenging. Multi-planar Single-shot T2-weighted (T2W) Fast Spin-Echo sequences are recommended to optimally assess anatomic relations of disease. Multi-planar 3D-T1W Gradient Recalled Echo imaging before and after Gadolinium administration depicts the presence and type of enhancement and relation to arterial, venous, and collecting system structures. To improve urographic phase MRI, concentrated Gadolinium in the collecting systems should be diluted. Diffusion-Weighted Imaging (DWI) should be performed before Gadolinium administration to minimize T2* effects. Renal sinus cysts are common but can occasionally be confused for dilated collecting system or calyceal diverticula, with the latter communicating with the collecting system and filling on urographic phase imaging. Vascular lesions (e.g., aneurysm, fistulas) may mimic cystic (or solid) lesions on non-enhanced MRI but can be suspected by noting similar signal intensity to the blood pool and diagnosis can be confirmed with MR angiogram/venogram. Multilocular cystic nephroma commonly extends to the renal sinus, however, to date are indistinguishable from cystic renal cell carcinoma (RCC). Solid hilar tumors are most commonly RCC and urothelial cell carcinoma (UCC). Hilar RCC are heterogeneous, hypervascular with epicenter in the renal cortex compared to UCC which are centered in the collecting system, homogeneously hypovascular, and show profound restricted diffusion. Diagnosis of renal sinus invasion in RCC is critically important as it is the most common imaging cause of pre-operative under-staging of disease. Fat is a normal component of the renal sinus; however, amount of sinus fat correlates with cardiovascular disease and is also seen in lipomatosis. Fat-containing hilar lesions include lipomas, angiomyolipomas, and less commonly other tumors which engulf sinus

  1. Single-shot spiral imaging at 7 T.

    Science.gov (United States)

    Engel, Maria; Kasper, Lars; Barmet, Christoph; Schmid, Thomas; Vionnet, Laetitia; Wilm, Bertram; Pruessmann, Klaas P

    2018-03-25

    The purpose of this work is to explore the feasibility and performance of single-shot spiral MRI at 7 T, using an expanded signal model for reconstruction. Gradient-echo brain imaging is performed on a 7 T system using high-resolution single-shot spiral readouts and half-shot spirals that perform dual-image acquisition after a single excitation. Image reconstruction is based on an expanded signal model including the encoding effects of coil sensitivity, static off-resonance, and magnetic field dynamics. The latter are recorded concurrently with image acquisition, using NMR field probes. The resulting image resolution is assessed by point spread function analysis. Single-shot spiral imaging is achieved at a nominal resolution of 0.8 mm, using spiral-out readouts of 53-ms duration. High depiction fidelity is achieved without conspicuous blurring or distortion. Effective resolutions are assessed as 0.8, 0.94, and 0.98 mm in CSF, gray matter and white matter, respectively. High image quality is also achieved with half-shot acquisition yielding image pairs at 1.5-mm resolution. Use of an expanded signal model enables single-shot spiral imaging at 7 T with unprecedented image quality. Single-shot and half-shot spiral readouts deploy the sensitivity benefit of high field for rapid high-resolution imaging, particularly for functional MRI and arterial spin labeling. © 2018 International Society for Magnetic Resonance in Medicine.

  2. MRI-based diagnostic imaging of the intratemporal facial nerve

    International Nuclear Information System (INIS)

    Kress, B.; Baehren, W.

    2001-01-01

    Detailed imaging of the five sections of the full intratemporal course of the facial nerve can be achieved by MRI and using thin tomographic section techniques and surface coils. Contrast media are required for tomographic imaging of pathological processes. Established methods are available for diagnostic evaluation of cerebellopontine angle tumors and chronic Bell's palsy, as well as hemifacial spasms. A method still under discussion is MRI for diagnostic evaluation of Bell's palsy in the presence of fractures of the petrous bone, when blood volumes in the petrous bone make evaluation even more difficult. MRI-based diagnostic evaluation of the idiopatic facial paralysis currently is subject to change. Its usual application cannot be recommended for routine evaluation at present. However, a quantitative analysis of contrast medium uptake of the nerve may be an approach to improve the prognostic value of MRI in acute phases of Bell's palsy. (orig./CB) [de

  3. The OMERACT rheumatoid arthritis magnetic resonance imaging (MRI) scoring system

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Peterfy, Charles G.; Bird, Paul

    2017-01-01

    Objective: The Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis (RA) Magnetic Resonance Imaging (MRI) scoring system (RAMRIS), evaluating bone erosion, bone marrow edema/osteitis, and synovitis, was introduced in 2002, and is now the standard method of objectively quantifying...... inflammation and damage by MRI in RA trials. The objective of this paper was to identify subsequent advances and based on them, to provide updated recommendations for the RAMRIS. Methods: MRI studies relevant for RAMRIS and technical and scientific advances were analyzed by the OMERACT MRI in Arthritis Working...... Group, which used these data to provide updated considerations on image acquisition, RAMRIS definitions, and scoring systems for the original and new RA pathologies. Further, a research agenda was outlined. Results: Since 2002, longitudinal studies and clinical trials have documented RAMRIS variables...

  4. Development and application of PET-MRI image fusion technology

    International Nuclear Information System (INIS)

    Song Jianhua; Zhao Jinhua; Qiao Wenli

    2011-01-01

    The emerging and growing in popularity of PET-CT scanner brings us the convenience and cognizes the advantages such as diagnosis, staging, curative effect evaluation and prognosis for malignant tumor. And the PET-MRI installing maybe a new upsurge when the machine gradually mature, because of the MRI examination without the radiation exposure and with the higher soft tissue resolution. This paper summarized the developing course of image fusion technology and some researches of clinical application about PET-MRI at present, in order to help people to understand the functions and know its wide application of the upcoming new instrument, mainly focuses the application on the central nervous system and some soft tissue lesions. And before PET-MRI popularization, people can still carry out some researches of various image fusion and clinical application on the current equipment. (authors)

  5. Virtual phantom magnetic resonance imaging (ViP MRI) on a clinical MRI platform.

    Science.gov (United States)

    Saint-Jalmes, Hervé; Bordelois, Alejandro; Gambarota, Giulio

    2018-01-01

    The purpose of this study was to implement Virtual Phantom Magnetic Resonance Imaging (ViP MRI), a technique that allows for generating reference signals in MR images using radiofrequency (RF) signals, on a clinical MR system and to test newly designed virtual phantoms. MRI experiments were conducted on a 1.5 T MRI scanner. Electromagnetic modelling of the ViP system was done using the principle of reciprocity. The ViP RF signals were generated using a compact waveform generator (dimensions of 26 cm × 18 cm × 16 cm), connected to a homebuilt 25 mm-diameter RF coil. The ViP RF signals were transmitted to the MRI scanner bore, simultaneously with the acquisition of the signal from the object of interest. Different types of MRI data acquisition (2D and 3D gradient-echo) as well as different phantoms, including the Shepp-Logan phantom, were tested. Furthermore, a uniquely designed virtual phantom - in the shape of a grid - was generated; this newly proposed phantom allows for the investigations of the vendor distortion correction field. High quality MR images of virtual phantoms were obtained. An excellent agreement was found between the experimental data and the inverse cube law, which was the expected functional dependence obtained from the electromagnetic modelling of the ViP system. Short-term time stability measurements yielded a coefficient of variation in the signal intensity over time equal to 0.23% and 0.13% for virtual and physical phantom, respectively. MR images of the virtual grid-shaped phantom were reconstructed with the vendor distortion correction; this allowed for a direct visualization of the vendor distortion correction field. Furthermore, as expected from the electromagnetic modelling of the ViP system, a very compact coil (diameter ~ cm) and very small currents (intensity ~ mA) were sufficient to generate a signal comparable to that of physical phantoms in MRI experiments. The ViP MRI technique was successfully implemented on a clinical MR

  6. PCA-based groupwise image registration for quantitative MRI

    NARCIS (Netherlands)

    Huizinga, W.; Poot, D. H. J.; Guyader, J.-M.; Klaassen, R.; Coolen, B. F.; van Kranenburg, M.; van Geuns, R. J. M.; Uitterdijk, A.; Polfliet, M.; Vandemeulebroucke, J.; Leemans, A.; Niessen, W. J.; Klein, S.

    2016-01-01

    Quantitative magnetic resonance imaging (qMRI) is a technique for estimating quantitative tissue properties, such as the T5 and T2 relaxation times, apparent diffusion coefficient (ADC), and various perfusion measures. This estimation is achieved by acquiring multiple images with different

  7. Imaging the premature brain: ultrasound or MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Vries, Linda S. de; Benders, Manon J.N.L.; Groenendaal, Floris [UMC Utrecht, Department of Neonatology, Wilhelmina Children' s Hospital, PO Box 85090, Utrecht (Netherlands)

    2013-09-15

    Neuroimaging of preterm infants has become part of routine clinical care, but the question is often raised on how often cranial ultrasound should be done and whether every high risk preterm infant should at least have one MRI during the neonatal period. An increasing number of centres perform an MRI either at discharge or around term equivalent age, and a few centres have access to a magnet in or adjacent to the neonatal intensive care unit and are doing sequential MRIs. In this review, we try to discuss when best to perform these two neuroimaging techniques and the additional information each technique may provide. (orig.)

  8. gr-MRI: A software package for magnetic resonance imaging using software defined radios

    Science.gov (United States)

    Hasselwander, Christopher J.; Cao, Zhipeng; Grissom, William A.

    2016-09-01

    The goal of this work is to develop software that enables the rapid implementation of custom MRI spectrometers using commercially-available software defined radios (SDRs). The developed gr-MRI software package comprises a set of Python scripts, flowgraphs, and signal generation and recording blocks for GNU Radio, an open-source SDR software package that is widely used in communications research. gr-MRI implements basic event sequencing functionality, and tools for system calibrations, multi-radio synchronization, and MR signal processing and image reconstruction. It includes four pulse sequences: a single-pulse sequence to record free induction signals, a gradient-recalled echo imaging sequence, a spin echo imaging sequence, and an inversion recovery spin echo imaging sequence. The sequences were used to perform phantom imaging scans with a 0.5 Tesla tabletop MRI scanner and two commercially-available SDRs. One SDR was used for RF excitation and reception, and the other for gradient pulse generation. The total SDR hardware cost was approximately 2000. The frequency of radio desynchronization events and the frequency with which the software recovered from those events was also measured, and the SDR's ability to generate frequency-swept RF waveforms was validated and compared to the scanner's commercial spectrometer. The spin echo images geometrically matched those acquired using the commercial spectrometer, with no unexpected distortions. Desynchronization events were more likely to occur at the very beginning of an imaging scan, but were nearly eliminated if the user invoked the sequence for a short period before beginning data recording. The SDR produced a 500 kHz bandwidth frequency-swept pulse with high fidelity, while the commercial spectrometer produced a waveform with large frequency spike errors. In conclusion, the developed gr-MRI software can be used to develop high-fidelity, low-cost custom MRI spectrometers using commercially-available SDRs.

  9. Protocol of a single group prospective observational study on the diagnostic value of 3T susceptibility weighted MRI of nigrosome-1 in patients with parkinsonian symptoms: the N3iPD study (nigrosomal iron imaging in Parkinson's disease).

    Science.gov (United States)

    Schwarz, Stefan T; Xing, Yue; Naidu, Saadnah; Birchall, Jim; Skelly, Rob; Perkins, Alan; Evans, Jonathan; Sare, Gill; Martin-Bastida, Antonio; Bajaj, Nin; Gowland, Penny; Piccini, Paola; Auer, Dorothee P

    2017-12-14

    Parkinson's disease (PD) is the most common movement disorder in the elderly and is characterised clinically by bradykinesia, tremor and rigidity. Diagnosing Parkinson's can be difficult especially in the early stages. High-resolution nigrosome MRI offers promising diagnostic accuracy of patients with established clinical symptoms; however, it is unclear whether this may help to establish the diagnosis in the early stages of PD, when there is diagnostic uncertainty. In this scenario, a single photon emission CT scan using a radioactive dopamine transporter ligand can help to establish the diagnosis, or clinical follow-up may eventually clarify the diagnosis. A non-invasive, cost-effective diagnostic test that could replace this would be desirable. We therefore aim to prospectively test whether nigrosome MRI is as useful as DaTSCAN to establish the correct diagnosis in people with minor or unclear symptoms suspicious for PD. In a prospective study we will recruit 145 patients with unclear symptoms possibly caused by Parkinson's from three movement disorder centres in the UK to take part in the study. We will record the Movement Disorder Society - Unified Parkinson's Disease Rating Scale, and participants will undergo DaTSCAN and high-resolution susceptibility weighted MRI at a field strength of 3T. DaTSCANs will be assessed visually and semiquantitatively; MRI scans will be visually assessed for signal loss in nigrosome-1 by blinded investigators. We will compare how the diagnosis suggested by MRI compares with the diagnosis based on DaTSCAN and will also validate the diagnosis based on the two tests with a clinical examination performed at least 1 year after the initial presentation as a surrogate gold standard diagnostic test. The local ethics commission (Health Research Authority East Midlands - Derby Research Ethics Committee) has approved this study (REC ref.: 16/EM/0229). The study is being carried out under the principles of the Declaration of Helsinki (64

  10. Elemental imaging of MRI contrast agents: benchmarking of LA-ICP-MS to MRI

    Energy Technology Data Exchange (ETDEWEB)

    Pugh, J.A.T. [University of Sheffield, Centre for Analytical Sciences, Sheffield (United Kingdom); University of Sheffield, Department of Chemical and Biological Engineering, Sheffield (United Kingdom); Cox, A.G.; McLeod, C.W. [University of Sheffield, Centre for Analytical Sciences, Sheffield (United Kingdom); Bunch, J. [University of Birmingham, School of Chemistry, Birmingham (United Kingdom); Writer, M.J.; Hart, S.L. [UCL Institute of Child Health, Wolfson Centre for Gene Therapy of Childhood Disease, London (United Kingdom); Bienemann, A.; White, E. [University of Bristol, School of Clinical Sciences, Southmead Hospital, Bristol (United Kingdom); Bell, J. [Hammersmith Hospital, Metabolic and Molecular Imaging Group, MRC Clinical Sciences Centre, Imperial College London, London (United Kingdom)

    2012-06-15

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been used to map the spatial distribution of magnetic resonance imaging (MRI) contrast agents (Gd-based) in histological sections in order to explore synergies with in vivo MRI. Images from respective techniques are presented for two separate studies namely (1) convection enhanced delivery of a Gd nanocomplex (developmental therapeutic) into rat brain and (2) convection enhanced delivery, with co-infusion of Magnevist (commercial Gd contrast agent) and Carboplatin (chemotherapy drug), into pig brain. The LA technique was shown to be a powerful compliment to MRI not only in offering improved sensitivity, spatial resolution and signal quantitation but also in giving added value regarding the fate of administered agents (Gd and Pt agents). Furthermore simultaneous measurement of Fe enabled assignment of an anomalous contrast enhancement region in rat brain to haemorrhage at the infusion site. (orig.)

  11. Magnetic resonance imaging (MRI) in obstetrics. II. Fetal anatomy.

    Science.gov (United States)

    Powell, M C; Worthington, B S; Buckley, J M; Symonds, E M

    1988-01-01

    Magnetic resonance imaging (MRI) was performed in 36 patients at between 10 and 38 weeks gestation to determine the fetal anatomy that could be identified at different gestations. Fetal motion significantly degraded the image quality in the first and second trimesters, but in the final trimester fetal anatomy was clearly demonstrated. T2 weighted sequences showed the fetal brain and lungs to have a high signal intensity. Shorter TR leading to a T1 weighting gave better resolution of the overall anatomy. MRI has revealed the potential for assessment of lung maturity and the growth-retarded fetus.

  12. A protocol for patients with cardiovascular implantable devices undergoing magnetic resonance imaging (MRI): should defibrillation threshold testing be performed post-(MRI).

    Science.gov (United States)

    Burke, Peter Thomas; Ghanbari, Hamid; Alexander, Patrick B; Shaw, Michael K; Daccarett, Marcos; Machado, Christian

    2010-06-01

    Magnetic resonance imaging (MRI) in patients with Cardiovascular Implantable Electronic Devices (CIED) has not been approved by the Food and Drug Administration. Recent data suggests MRI as a relative rather than absolute contraindication in CIED patients. Recently, the American Heart Association has recommended defibrillation threshold testing (DFTT) in implantable cardioverter defibrillator (ICD) patients undergoing MRI. We evaluated the feasibility and safety of a protocol for MRI in CIED patients, incorporating the new recommendations on DFTT. Consecutive patients with CIED undergoing MRI were included. The protocol consisted of continuous monitoring during imaging, device interrogation pre- and post-MRI, reprogramming of the pacemaker to an asynchronous mode in pacemaker-dependent (PMD) patients and a non-tracking/sensing mode for non-PMD patients. All tachyarrhythmia therapies were disabled. Devices were interrogated for lead impedance, battery life, pacing, and sensing thresholds. All patients with ICD underwent DFTT/defibrillator safety margin testing (DSMT) post-MRI. A total of 92 MRI's at 1.5 Tesla were performed in 38 patients. A total of 13 PMD patients, ten ICD patients, four cardiac resynchronization therapy with defibrillator (CRT-D) patients, and 11 non-PMD patients were scanned from four major manufacturers. No device circuitry damage, programming alterations, inappropriate shocks, failure to pace, or changes in sensing, pacing, or defibrillator thresholds were found on single or multiple MRI sessions. Our protocol for MRI in CIED patients appears safe, feasible, and reproducible. This is irrespective of the type of CIED, pacemaker dependancy or multiple 24-h scanning sessions. Our protocol addresses early detection of potential complications and establishes a response system for potential device-related complications. Our observation suggests that routine DFTT/DSMT post-MRI may not be necessary.

  13. Functional imaging of the kidneys with fast MRI techniques

    International Nuclear Information System (INIS)

    Prasad, P.V.; Priatna, A.

    1999-01-01

    Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  14. Functional imaging of the kidneys with fast MRI techniques

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, P.V.; Priatna, A. [AN-234, MRI Research, Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Ave., Boston, MA (United States)

    1999-02-01

    Availability of faster and stronger gradient systems have given rise to a multitude of fast MRI data acquisition strategies which have tremendously increased the scope of MRI applications. These have led to the realization of long desired comprehensive approaches to evaluate anatomy and function using a single modality. In this work, we describe some of our own experiences with functional evaluation of the kidneys using MRI. Examples that suggest the feasibility of comprehensive approaches for evaluation of renal disease are also provided. We also introduce BOLD renal MRI, a method that may allow basic understanding of human renal physiology and pathophysiology in a way that has not been previously possible. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  15. Fetal cerebral imaging - ultrasound vs. MRI: an update.

    Science.gov (United States)

    Blondiaux, Eléonore; Garel, Catherine

    2013-11-01

    The purpose of this article is to analyze the advantages and limitations of prenatal ultrasonography (US) and magnetic resonance imaging (MRI) in the evaluation of the fetal brain. These imaging modalities should not be seen as competitive but rather as complementary. There are wide variations in the world regarding screening policies, technology, skills, and legislation about termination of pregnancy, and these variations markedly impact on the way of using prenatal imaging. According to the contribution expected from each technique and to local working conditions, one should choose the most appropriate imaging modality on a case-by-case basis. The advantages and limitations of US and MRI in the setting of fetal brain imaging are displayed. Different anatomical regions (midline, ventricles, subependymal area, cerebral parenchyma, pericerebral space, posterior fossa) and pathological conditions are analyzed and illustrated in order to compare the respective contribution of each technique. An accurate prenatal diagnosis of cerebral abnormalities is of utmost importance for prenatal counseling.

  16. Magnetic Resonance Medical Imaging (MRI)-from the inside

    Science.gov (United States)

    Bottomley, Paul

    There are about 36,000 magnetic resonance imaging (MRI) scanners in the world, with annual sales of 2500. In the USA about 34 million MRI studies are done annually, and 60-70% of all scanners operate at 1.5 Tesla (T). In 1982 there were none. How MRI got to be-and how it got to1.5T is the subject of this talk. Its an insider's view-mine-as a physics PhD student at Nottingham University when MRI (almost) began, through to the invention of the 1.5T clinical MRI scanner at GE's research center in Schenectady NY.Before 1977 all MRI was done on laboratory nuclear magnetic resonance instruments used for analyzing small specimens via chemical shift spectroscopy (MRS). It began with Lauterbur's 1973 observation that turning up the spectrometer's linear gradient magnetic field, generated a spectrum that was a 1D projection of the sample in the direction of the gradient. What followed in the 70's was the development of 3 key methods of 3D spatial localization that remain fundamental to MRI today.As the 1980's began, the once unimaginable prospect of upscaling from 2cm test-tubes to human body-sized magnets, gradient and RF transmit/receive systems, was well underway, evolving from arm-sized, to whole-body electromagnet-based systems operating at plan was to drop the field to 0.3T. We opted to make MRI work at 1.5T instead. The result was a scanner that could study both anatomy and metabolism with a SNR way beyond its lower field rivals. MRI's success truly reflects the team efforts of many: from the NMR physics to the engineering of magnets, gradient and RF systems.

  17. Coronary imaging techniques with emphasis on CT and MRI

    International Nuclear Information System (INIS)

    Lederlin, Mathieu; Latrabe, Valerie; Corneloup, Olivier; Cochet, Hubert; Montaudon, Michel; Laurent, Francois; Thambo, Jean-Benoit

    2011-01-01

    Coronary artery imaging in children is challenging, with high demands both on temporal and spatial resolution due to high heart rates and smaller anatomy. Although invasive conventional coronary angiography remains the benchmark technique, over the past 10 years, CT and MRI have emerged in the field of coronary imaging. The choice of hardware is important. For CT, the minimum requirement is a 64-channel scanner. The temporal resolution of the scanner is most important for optimising image quality and minimising radiation dose. Manufacturers have developed several modes of electrocardiographic (ECG) triggering to facilitate dose reduction. Recent technical advances have opened new possibilities in MRI coronary imaging. As a non-ionising radiation technique, MRI is of great interest in paediatric imaging. It is currently recommended in centres with appropriate expertise for the screening of patients with suspected congenital coronary anomalies. However, MRI is still not feasible in infants. This review describes and discusses the technical requirements and the pros and cons of all three techniques. (orig.)

  18. Reference-free unwarping of single-shot spatiotemporally encoded MRI using asymmetric self-refocused echoes acquisition

    Science.gov (United States)

    Chen, Ying; Chen, Song; Zhong, Jianhui; Chen, Zhong

    2015-05-01

    This paper presents a phase evolution rewinding algorithm for correcting the geometric and intensity distortions in single-shot spatiotemporally encoded (SPEN) MRI with acquisition of asymmetric self-refocused echo trains. Using the field map calculated from the phase distribution of the source image, the off-resonance induced phase errors are successfully rewound through deconvolution. The alias-free partial Fourier transform reconstruction helps improve the signal-to-noise ratio of the field maps and the output images. The effectiveness of the proposed algorithm was validated through 7 T MRI experiments on a lemon, a water phantom, and in vivo rat head. SPEN imaging was evaluated using rapid acquisition by sequential excitation and refocusing (RASER) which produces uniform T2 weighting. The results indicate that the new technique can more robustly deal with the cases in which the images obtained with conventional single-shot spin-echo EPI are difficult to be restored due to serious field variations.

  19. Initial experience of oculodynamic MRI using ultrafast T2-weighted imaging

    International Nuclear Information System (INIS)

    Tanitame, Keizo; Kaichi, Yoko; Nakamura, Yuko

    2013-01-01

    We designed cine MRI protocol using sequential static half-Fourier single-shot rapid acquisition with relaxation enhancement (RARE) images with the subjects staring at the series of targets in front of their eyes. This technique was applied to three healthy volunteers and four patients with ocular motility disorders, including blow-out fracture, globe restriction due to a large posterior staphyloma, neurogenic strabismus (convergence disorder), and intraocular adhesion. In the volunteers, smooth movements of their visual foci and extraocular muscles were observed. In the patients, the ocular movement disturbances were demonstrated. Oculodynamic MRI provides functional information in cases of diplopia. (author)

  20. Soft tissue manifestations of early rheumatic disease. Imaging with MRI

    International Nuclear Information System (INIS)

    Treitl, M.; Panteleon, A.; Koerner, M.; Becker-Gaab, C.; Reiser, M.; Wirth, S.

    2006-01-01

    The aim of this study was to evaluate typical magnetic resonance imaging (MRI) findings in early rheumatic diseases manifesting at the soft tissues of the hand using a retrospective analysis. A total of 186 MRI examinations of patients with clinical suspicion of a rheumatic disease were evaluated in a consensus reading by two experienced radiologists. All imaging patterns were assessed with respect to their type and localization. Under blinded and non-blinded conditions diagnoses were correlated with final clinical diagnosis. The most frequent diagnoses were rheumatoid arthritis (RA, 45.7%) and psoriatic arthritis (PsA, 15.6%). The mean correlation between clinical and MRI diagnosis (r) was 0.75 in blinded and 0.853 in non-blinded reading (p [de

  1. Combined 3 Tesla MRI Biomarkers Improve the Differentiation between Benign vs Malignant Single Ring Enhancing Brain Masses.

    Directory of Open Access Journals (Sweden)

    Simone Salice

    Full Text Available To evaluate whether the combination of imaging biomarkers obtained by means of different 3 Tesla (3T Magnetic Resonance Imaging (MRI advanced techniques can improve the diagnostic accuracy in the differentiation between benign and malignant single ring-enhancing brain masses.14 patients presenting at conventional 3T MRI single brain mass with similar appearance as regard ring enhancement, presence of peri-lesional edema and absence of hemorrhage signs were included in the study. All lesions were histologically proven: 5 pyogenic abscesses, 6 glioblastomas, and 3 metastases. MRI was performed at 3 Tesla and included Diffusion Weighted Imaging (DWI, Dynamic Susceptibility Contrast -Perfusion Weighted Imaging (DSC-PWI, Magnetic Resonance Spectroscopy (MRS, and Diffusion Tensor Imaging (DTI. Imaging biomarkers derived by those advanced techniques [Cerebral Blood Flow (CBF, relative Cerebral Blood Volume (rCBV, relative Main Transit Time (rMTT, Choline (Cho, Creatine (Cr, Succinate, N-Acetyl Aspartate (NAA, Lactate (Lac, Lipids, relative Apparent Diffusion Coefficient (rADC, and Fractional Anisotropy (FA] were detected by two experienced neuroradiologists in joint session in 4 areas: Internal Cavity (IC, Ring Enhancement (RE, Peri-Lesional edema (PL, and Contralateral Normal Appearing White Matter (CNAWM. Significant differences between benign (n = 5 and malignant (n = 9 ring enhancing lesions were tested with Mann-Withney U test. The diagnostic accuracy of MRI biomarkers taken alone and MRI biomarkers ratios were tested with Receiver Operating Characteristic (ROC analysis with an Area Under the Curve (AUC ≥ 0.9 indicating a very good diagnostic accuracy of the variable.Five MRI biomarker ratios achieved excellent accuracy: IC-rADC/PL-NAA (AUC = 1, IC-rADC/IC-FA (AUC = 0.978, RE-rCBV/RE-FA (AUC = 0.933, IC-rADC/RE-FA (AUC = 0.911, and IC-rADC/PL-FA (AUC = 0.911. Only IC-rADC achieved a very good diagnostic accuracy (AUC = 0.909 among MRI biomarkers

  2. Opening the black box: imaging nanoparticle transport with MRI

    Science.gov (United States)

    Phoenix, V.; Holmes, W. M.

    2009-12-01

    While most renown for its use in medicine, magnetic resonance imaging (MRI) has tremendous potential in the study of environmental processes. Its ability to non-invasively image inside materials that are opaque to other imaging methods (in particular light based techniques) is a particular strength. MRI has already been used, for example, to study fluid flow in rocks and image mass transport and biogeochemical processes in biofilms [1-4]. Here, we report of the use of MRI to image nanoparticle transport through porous geologic media (in this case packed gravel columns). Packed column experiments are key to understanding nanoparticulate transport in porous geologic media. Whilst highly informative, the data obtained can be a bulk average of a complex and heterogeneous array of interactions within the column. Natural environmental systems are often complex, displaying heterogeneity in geometry, hydrodynamics, geochemistry and microbiology throughout. MRI enables us to quantify better how this heterogeneity may influence nanoparticle transport and fate by enabling us to look inside the column and image the movement of nanoparticles within. To make the nanoparticle readily visible to MRI, it is labelled with a paramagnetic tag (commonly gadolinium). Indeed, a wide variety of off-the-shelf paramagnetically tagged nanoparticles and macromolecules are available, each with different properties enabling us to explore the impact of particle charge, size etc on their transport behaviour. In this preliminary study, packed columns of quartz or marble based gravels (approx 5 mm diameter) were first imaged to check their suitability for MR imaging. This was done as geologic material can contain sufficiently high concentrations of ferro- and paramagnetic ions to induce unwanted artefacts in the MR image. All gravels imaged (Rose quartz, Creswick quartz gravel and Ben Deulin white marble) produced minimal or no artefacts. A solution of the nanoparticle GadoCELLTrack (BioPAL), was

  3. Performance evaluation of cardiac MRI image denoising techniques

    NARCIS (Netherlands)

    AlAttar, M.A.; Mohamed, A.G.A.; Osman, N.F.; Fahmy, A.S.

    2008-01-01

    Black-blood cardiac magnetic resonance imaging (MRI) plays an important role in diagnosing a number of heart diseases. The technique suffers inherently from low contrast-to-noise ratio between the myocardium and the blood. In this work, we examined the performance of different classification

  4. Image quality transfer and applications in diffusion MRI

    DEFF Research Database (Denmark)

    Alexander, Daniel C.; Zikic, Darko; Ghosh, Aurobrata

    2017-01-01

    and the uniquely rich diffusion MRI data set from the human connectome project (HCP). Results highlight potential benefits of IQT in both brain connectivity mapping and microstructure imaging. In brain connectivity mapping, IQT reveals, from standard data sets, thin connection pathways that tractography normally...

  5. Multi-modal image registration: matching MRI with histology

    NARCIS (Netherlands)

    Alić, L.; Haeck, J.C.; Klein, S.; Bol, K.; Tiel, S.T. van; Wielopolski, P.A.; Bijster, M.; Niessen, W.J.; Bernsen, M.; Veenland, J.F.; Jong, M. de

    2010-01-01

    Spatial correspondence between histology and multi sequence MRI can provide information about the capabilities of non-invasive imaging to characterize cancerous tissue. However, shrinkage and deformation occurring during the excision of the tumor and the histological processing complicate the co

  6. Design, operation, and safety of single-room interventional MRI suites: practical experience from two centers.

    Science.gov (United States)

    White, Mark J; Thornton, John S; Hawkes, David J; Hill, Derek L G; Kitchen, Neil; Mancini, Laura; McEvoy, Andrew W; Razavi, Reza; Wilson, Sally; Yousry, Tarek; Keevil, Stephen F

    2015-01-01

    The design and operation of a facility in which a magnetic resonance imaging (MRI) scanner is incorporated into a room used for surgical or endovascular cardiac interventions presents several challenges. MR safety must be maintained in the presence of a much wider variety of equipment than is found in a diagnostic unit, and of staff unfamiliar with the MRI environment, without compromising the safety and practicality of the interventional procedure. Both the MR-guided cardiac interventional unit at Kings College London and the intraoperative imaging suite at the National Hospital for Neurology and Neurosurgery are single-room interventional facilities incorporating 1.5 T cylindrical-bore MRI scanners. The two units employ similar strategies to maintain MR safety, both in original design and day-to-day operational workflows, and between them over a decade of incident-free practice has been accumulated. This article outlines these strategies, highlighting both similarities and differences between the units, as well as some lessons learned and resulting procedural changes made in both units since installation. © 2014 Wiley Periodicals, Inc.

  7. DWI-MRI: Single, Informative, and Noninvasive Technique for Prostate Cancer Diagnosis

    Directory of Open Access Journals (Sweden)

    Elhousseiny I. Ibrahiem

    2012-01-01

    Full Text Available Aim. To evaluate diffusion weighted image-MRI (DWI as a single diagnostic noninvasive MRI technique for prostate cancer (PCa diagnosis. Material and Methods. A prospective study was conducted between July 2008 and July 2009. Candidates patients were equal or more than 40 years old, with suspicious digital rectal examination (more than clinical T2 or PSA >4 ng/mL. Informed consent was signed. DWI-MRI was performed at 1.5 T with a body coil combined with a spine coil in consecutive 100 cases. The histopathology of biopsies has been used as reference standard. Two examiners were evaluating MRI and TRUS, both of them were blinded regarding pathological findings. Accuracy, specificity, and sensitivity were statistically analyzed. Results. Based on pathological diagnosis: group A (cancerous; 75 cases and group B (non-cancerous; 25 cases. Mean age was 65.3 and 62.8 years in groups A and B, respectively. Mean PSA was 30.7 and 9.2 ng/mL in groups A and B, respectively. Sensitivity of DWI was 58.3% while specificity was 83.8%. Accuracy of lesion detection was 52.4–77.8% (<0.05. Moreover, DWI at ADC value 1.2×10−3 mL/sec could determine 82.4% of true positive cases (<0.05. ADC values were lower with Gleason score ≥7 (<0.05. Conclusion. DWI could represent a non invasive single diagnostic tool not only in detection and localization but also in prediction of Gleason score whenever DWI is used prior to invasive TRUS biopsy. Furthermore, targeted single biopsy could be planned after DWI to minimize patient morbidity by invasive techniques.

  8. Magnetic resonance imaging (MRI) of intracranial chordomas

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Teruo; Inoue, Yuichi; Shakudo, Miyuki and others

    1988-03-01

    MR images of 5 patients with intracranial chordoma were evaluated and compared with those of other clival lesions (1 clival osteomyelitis, 1 metastatic clival tumor, 3 clival meningiomas). The MR examination was performed using a 0.5 T superconductive magnet, with approximately 10 mm section thickness, one average and a 256 x 256 matrix. T1 weighted images were obtainned by inversion recovery (IR) with TR 2100 - 2500 msec, TI 600 msec and TE 40 msec. T2 weighted images were obtained by spin echo pulse sequence with TR 1800 - 2500 msec and TE 120 msec (long SE). In several cases, the spin echo pulse sequences with TR 1000 msec and TE 40 msec (short SE) were also done. Multiplaned images were obtained. Four of 5 intracranial chordomas were low in intensity compared to cerebral gray matter on T1 weighted images, and all of 5 chordomas were as high in intensity as cerebrospinal fluid or higher than that of cerebrospinal fluid on T2 weighted images. Clival fatty marrow is high intensity on T1 weighted images. Clival involvement by a tumor was a clearly demonstrated as disappearance of this high intensity in all cases. In two cases, the tumor extended to the retropharyngeal space and this was detected clearly on short SE image. Although clival fatty marrow was disappeared, osteomyelitis and metastatic tumor in clivus were iso-intense to cerebral gray matter on both T1 and T2 weighted images. All of 3 clival meningiomas showed iso-intensity to cerebral gray matter on T1 weighted images and slightly high intensity to brain on T2 weighted images, and clival fatty marrow was normal in all 3 cases. Although our experiences are limited in number, intracranial chordoma appeared to be differentiated from other clival lesions.

  9. MRI of Creutzfeldt-Jakob disease: Imaging features and recommended MRI protocol

    Energy Technology Data Exchange (ETDEWEB)

    Collie, D.A.; Sellar, R.J.; Zeidler, M.; Colchester, A.C.F.; Knight, R.; Will, R.G

    2001-09-01

    Creutzfeldt-Jakob Disease (CJD) is a rare, progressive and invariably fatal neurodegenerative disease characterized by specific histopathological features. Of the four subtypes of CJD described, the commonest is sporadic CJD (sCJD). More recently, a new clinically distinct form of the disease affecting younger patients, known as variant CJD (vCJD), has been identified, and this has been causally linked to the bovine spongiform encephalopathy (BSE) agent in cattle. Characteristic appearances on magnetic resonance imaging (MRI) have been identified in several forms of CJD; sCJD may be associated with high signal changes in the putamen and caudate head and vCJD is usually associated with hyperintensity of the pulvinar (posterior nuclei) of the thalamus. These appearances and other imaging features are described in this article. Using appropriate clinical and radiological criteria and tailored imaging protocols, MRI plays an important part in the in vivodiagnosis of this disease. Collie, D.A. et al. (2001)

  10. MRI of Creutzfeldt-Jakob disease: Imaging features and recommended MRI protocol

    International Nuclear Information System (INIS)

    Collie, D.A.; Sellar, R.J.; Zeidler, M.; Colchester, A.C.F.; Knight, R.; Will, R.G.

    2001-01-01

    Creutzfeldt-Jakob Disease (CJD) is a rare, progressive and invariably fatal neurodegenerative disease characterized by specific histopathological features. Of the four subtypes of CJD described, the commonest is sporadic CJD (sCJD). More recently, a new clinically distinct form of the disease affecting younger patients, known as variant CJD (vCJD), has been identified, and this has been causally linked to the bovine spongiform encephalopathy (BSE) agent in cattle. Characteristic appearances on magnetic resonance imaging (MRI) have been identified in several forms of CJD; sCJD may be associated with high signal changes in the putamen and caudate head and vCJD is usually associated with hyperintensity of the pulvinar (posterior nuclei) of the thalamus. These appearances and other imaging features are described in this article. Using appropriate clinical and radiological criteria and tailored imaging protocols, MRI plays an important part in the in vivodiagnosis of this disease. Collie, D.A. et al. (2001)

  11. In vivo imaging of stepwise vessel occlusion in cerebral photothrombosis of mice by 19F MRI.

    Directory of Open Access Journals (Sweden)

    Gesa Weise

    Full Text Available (19F magnetic resonance imaging (MRI was recently introduced as a promising technique for in vivo cell tracking. In the present study we compared (19F MRI with iron-enhanced MRI in mice with photothrombosis (PT at 7 Tesla. PT represents a model of focal cerebral ischemia exhibiting acute vessel occlusion and delayed neuroinflammation.Perfluorocarbons (PFC or superparamagnetic iron oxide particles (SPIO were injected intravenously at different time points after photothrombotic infarction. While administration of PFC directly after PT induction led to a strong (19F signal throughout the entire lesion, two hours delayed application resulted in a rim-like (19F signal at the outer edge of the lesion. These findings closely resembled the distribution of signal loss on T2-weighted MRI seen after SPIO injection reflecting intravascular accumulation of iron particles trapped in vessel thrombi as confirmed histologically. By sequential administration of two chemically shifted PFC compounds 0 and 2 hours after illumination the different spatial distribution of the (19F markers (infarct core/rim could be visualized in the same animal. When PFC were applied at day 6 the fluorine marker was only detected after long acquisition times ex vivo. SPIO-enhanced MRI showed slight signal loss in vivo which was much more prominent ex vivo indicative for neuroinflammation at this late lesion stage.Our study shows that vessel occlusion can be followed in vivo by (19F and SPIO-enhanced high-field MRI while in vivo imaging of neuroinflammation remains challenging. The timing of contrast agent application was the major determinant of the underlying processes depicted by both imaging techniques. Importantly, sequential application of different PFC compounds allowed depiction of ongoing vessel occlusion from the core to the margin of the ischemic lesions in a single MRI measurement.

  12. Periodontoid pseudotumor: CT and MRI imaging

    International Nuclear Information System (INIS)

    Yu, Eugene; Montanera, Walter

    2005-01-01

    Periodontoid pseudotumor (PP) can be a severe and disabling disease. This disease process typically presents in elderly patients with a longstanding history of myelopathy. We reviewed four cases of PP in order to summarize the clinical and imaging features. (orig.)

  13. Assessment of congenital heart disease (CHD): Is there a role for fetal magnetic resonance imaging (MRI)?

    Energy Technology Data Exchange (ETDEWEB)

    Manganaro, L. [Department of Radiological Sciences, UMBERTO I Hospital, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome (Italy); Savelli, S. [Department of Radiological Sciences, UMBERTO I Hospital, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome (Italy)], E-mail: sarasavelli@hotmail.it; Di Maurizio, M.; Perrone, A.; Francioso, A.; La Barbera, L.; Totaro, P.; Fierro, F.; Tomei, A.; Coratella, F. [Department of Radiological Sciences, UMBERTO I Hospital, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome (Italy); Giancotti, A. [Department of Gynaecological Sciences, UMBERTO I Hospital, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome (Italy); Ballesio, L. [Department of Radiological Sciences, UMBERTO I Hospital, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome (Italy); Ventriglia, F. [Department of Pediatric Cardiology, UMBERTO I Hospital, SAPIENZA University of Rome, Viale del Policlinico 155, 00161 Rome (Italy)

    2009-10-15

    Purpose: To review our experience with fetal magnetic resonance imaging (MRI) to evaluate congenital heart disease (CHD). Methods: We performed fetal MRI in 32 fetuses with an echocardiographically assessed CHD. Both direct and indirect signs of CHD were investigated. Direct signs considered were: morpho-volumetric abnormalities of the heart; malrotations; ventricular and atrial septal defects; anomalies of the origin, size and course of the great arteries. Indirect signs considered were: difficulty to recognize a 'normal' anatomical structures in the reference projections; increase of the vascular size before a stenosis; hypertrophy of the papillary muscles; cardiomegaly and pericardial effusion. All MRI findings were compared with postnatal or autoptic findings. Results: MRI allowed the CHD to be visualised by direct signs in 17 fetuses, indirect signs in 5 and both direct and indirect signs in 9 fetuses, excluding the prenatal echocardiographic suspect of hypoplastic left heart syndrome in 1 fetus. Postnatal echocardiograms or autoptic findings confirmed a normal heart in 1 fetus and CHD in 31 fetuses including a single cardiac anomaly or syndrome in 19 fetuses, 2 associated cardiac abnormalities in 11 and 3 cardiac anomalies in 1 fetus. However, in 2 fetuses MRI detected a ventricular septal defect successively disclosed by gold standard. Conclusions: MRI is a promising method for further assessment of the cardiovascular pathologies diagnosed by echocardiography, and may be a valuable tool in assessing associated extracardiac anomalies.

  14. 7T MRI in focal epilepsy with unrevealing conventional field strength imaging.

    Science.gov (United States)

    De Ciantis, Alessio; Barba, Carmen; Tassi, Laura; Cosottini, Mirco; Tosetti, Michela; Costagli, Mauro; Bramerio, Manuela; Bartolini, Emanuele; Biagi, Laura; Cossu, Massimo; Pelliccia, Veronica; Symms, Mark R; Guerrini, Renzo

    2016-03-01

    To assess the diagnostic yield of 7T magnetic resonance imaging (MRI) in detecting and characterizing structural lesions in patients with intractable focal epilepsy and unrevealing conventional (1.5 or 3T) MRI. We conducted an observational clinical imaging study on 21 patients (17 adults and 4 children) with intractable focal epilepsy, exhibiting clinical and electroencephalographic features consistent with a single seizure-onset zone (SOZ) and unrevealing conventional MRI. Patients were enrolled at two tertiary epilepsy surgery centers and imaged at 7T, including whole brain (three-dimensional [3D] T1 -weighted [T1W] fast-spoiled gradient echo (FSPGR), 3D susceptibility-weighted angiography [SWAN], 3D fluid-attenuated inversion recovery [FLAIR]) and targeted imaging (2D T2*-weighted dual-echo gradient-recalled echo [GRE] and 2D gray-white matter tissue border enhancement [TBE] fast spin echo inversion recovery [FSE-IR]). MRI studies at 1.5 or 3T deemed unrevealing at the referral center were reviewed by three experts in epilepsy imaging. Reviewers were provided information regarding the suspected localization of the SOZ. The same team subsequently reviewed 7T images. Agreement in imaging interpretation was reached through consensus-based discussions based on visual identification of structural abnormalities and their likely correlation with clinical and electrographic data. 7T MRI revealed structural lesions in 6 (29%) of 21 patients. The diagnostic gain in detection was obtained using GRE and FLAIR images. Four of the six patients with abnormal 7T underwent epilepsy surgery. Histopathology revealed focal cortical dysplasia (FCD) in all. In the remaining 15 patients (71%), 7T MRI remained unrevealing; 4 of the patients underwent epilepsy surgery and histopathologic evaluation revealed gliosis. 7T MRI improves detection of epileptogenic FCD that is not visible at conventional field strengths. A dedicated protocol including whole brain FLAIR and GRE images at 7T

  15. Whole-body MRI, dynamic contrast-enhanced MRI, and diffusion-weighted imaging for the staging of multiple myeloma

    Energy Technology Data Exchange (ETDEWEB)

    Dutoit, Julie C.; Verstraete, Koenraad L. [Ghent University Hospital, Department of Radiology, Ghent (Belgium)

    2017-06-15

    Magnetic resonance imaging (MRI) is the most sensitive imaging technique for the detection of bone marrow infiltration, and has therefore recently been included in the new diagnostic myeloma criteria, as proposed by the International Myeloma Working Group. Nevertheless, conventional MRI only provides anatomical information and is therefore only of limited use in the response assessment of patients with multiple myeloma. The additional information from functional MRI techniques, such as diffusion-weighted imaging and dynamic contrast-enhanced MRI, can improve the detection rate of bone marrow infiltration and the assessment of response. This can further enhance the sensitivity and specificity of MRI in the staging of multiple myeloma patients. This article provides an overview of the technical aspects of conventional and functional MRI techniques with practical recommendations. It reviews the diagnostic performance, prognostic value, and role in therapy assessment in multiple myeloma and its precursor stages. (orig.)

  16. Hyaluronic acid-functionalized single-walled carbon nanotubes as tumor-targeting MRI contrast agent

    Directory of Open Access Journals (Sweden)

    Hou L

    2015-07-01

    Full Text Available Lin Hou,* Huijuan Zhang,* Yating Wang, Lili Wang, Xiaomin Yang, Zhenzhong ZhangSchool of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, People’s Republic of China*These authors contributed equally to this workAbstract: A tumor-targeting carrier, hyaluronic acid (HA-functionalized single-walled carbon nanotubes (SWCNTs, was explored to deliver magnetic resonance imaging (MRI contrast agents (CAs targeting to the tumor cells specifically. In this system, HA surface modification for SWCNTs was simply accomplished by amidation process and could make this nanomaterial highly hydrophilic. Cellular uptake was performed to evaluate the intracellular transport capabilities of HA-SWCNTs for tumor cells and the uptake rank was HA-SWCNTs> SWCNTs owing to the presence of HA, which was also evidenced by flow cytometry. The safety evaluation of this MRI CAs was investigated in vitro and in vivo. It revealed that HA-SWCNTs could stand as a biocompatible nanocarrier and gadolinium (Gd/HA-SWCNTs demonstrated almost no toxicity compared with free GdCl3. Moreover, GdCl3 bearing HA-SWCNTs could significantly increase the circulation time for MRI. Finally, to investigate the MRI contrast enhancing capabilities of Gd/HA-SWCNTs, T1-weighted MR images of tumor-bearing mice were acquired. The results suggested Gd/HA-SWCNTs had the highest tumor-targeting efficiency and T1-relaxivity enhancement, indicating HA-SWCNTs could be developed as a tumor-targeting carrier to deliver the CAs, GdCl3, for the identifiable diagnosis of tumor.Keywords: gadolinium, magnetic resonance, SWCNTs, hyaluronic acid, contrast agent

  17. The case of Cushings disease imaging by SPECT examination without manifestation of adenoma in MRI examination

    International Nuclear Information System (INIS)

    Gierach, M.; Pufal, J.; Pilecki, S.; Junik, R.

    2005-01-01

    The aim of our study was to evaluate the possibility of imaging the pathological accumulation of 99mT c-MIBI in the pituitary gland in patients with Cushings disease when MRI examination does not show microadenomas. Cushings disease was diagnosed in a 27 year old male on the basis of clinical and biochemical findings. The blood cortisol level of the patient was elevated (the average level was 47 microgram/dl) and it showed no changeability of day and night rhythm. In the patient with Cushing's disease, during the SPECT examination, an increased accumulation of 99mT c-MIBI in the pituitary gland was noticed. MRI scanning was negative. Single photon emission computed tomography using 99mT c-MIBI is a useful and sensitive means of pituitary gland microadenoma detection in patients with Cushings disease when microadenoma is not detected during MRI scanning and when the results of dexamethasone suppression test is positive. (author)

  18. Imaging the fetus: when does MRI really help?

    International Nuclear Information System (INIS)

    Garel, Catherine

    It is widely accepted that fetal MRI should be used to complement rather than to replace US, which remains the primary screening modality. Under certain circumstances where US is limited, such as maternal obesity, fetal MRI may be useful as a primary screening tool. It is well known that maternal obesity is increasing worldwide and is more common in certain countries. It certainly contributes to a shift from US to MRI as a prenatal diagnostic imaging modality. Inadequacies of US may also be directly related to the sonographer's level of experience. Use and development of fetal US are not comparable in different countries. Some countries prioritise the development of fetal US and increase the experience of sonographers by political initiatives such as reimbursement of US by social insurance, thus raising people's expectations. In other countries, fetal US is considered of secondary importance and is not exploited as much as it could be. Consequently, in those countries, the place occupied by fetal MRI and the expectations regarding its diagnostic accuracy are much more prominent. This is undoubtedly the reason why there are so many discrepancies regarding the relative contributions of fetal MRI and fetal US in the prenatal literature. (orig.)

  19. Imaging the fetus: when does MRI really help?

    Energy Technology Data Exchange (ETDEWEB)

    Garel, Catherine [Hopital d' Enfants Armand-Trousseau, Service de Radiologie Pediatrique, Paris Cedex 12 (France)

    2008-06-15

    It is widely accepted that fetal MRI should be used to complement rather than to replace US, which remains the primary screening modality. Under certain circumstances where US is limited, such as maternal obesity, fetal MRI may be useful as a primary screening tool. It is well known that maternal obesity is increasing worldwide and is more common in certain countries. It certainly contributes to a shift from US to MRI as a prenatal diagnostic imaging modality. Inadequacies of US may also be directly related to the sonographer's level of experience. Use and development of fetal US are not comparable in different countries. Some countries prioritise the development of fetal US and increase the experience of sonographers by political initiatives such as reimbursement of US by social insurance, thus raising people's expectations. In other countries, fetal US is considered of secondary importance and is not exploited as much as it could be. Consequently, in those countries, the place occupied by fetal MRI and the expectations regarding its diagnostic accuracy are much more prominent. This is undoubtedly the reason why there are so many discrepancies regarding the relative contributions of fetal MRI and fetal US in the prenatal literature. (orig.)

  20. Non-invasive imaging of plant roots in different soils using magnetic resonance imaging (MRI

    Directory of Open Access Journals (Sweden)

    Daniel Pflugfelder

    2017-11-01

    Full Text Available Abstract Background Root systems are highly plastic and adapt according to their soil environment. Studying the particular influence of soils on root development necessitates the adaptation and evaluation of imaging methods for multiple substrates. Non-invasive 3D root images in soil can be obtained using magnetic resonance imaging (MRI. Not all substrates, however, are suitable for MRI. Using barley as a model plant we investigated the achievable image quality and the suitability for root phenotyping of six commercially available natural soil substrates of commonly occurring soil textures. The results are compared with two artificially composed substrates previously documented for MRI root imaging. Results In five out of the eight tested substrates, barley lateral roots with diameters below 300 µm could still be resolved. In two other soils, only the thicker barley seminal roots were detectable. For these two substrates the minimal detectable root diameter was between 400 and 500 µm. Only one soil did not allow imaging of the roots with MRI. In the artificially composed substrates, soil moisture above 70% of the maximal water holding capacity (WHCmax impeded root imaging. For the natural soil substrates, soil moisture had no effect on MRI root image quality in the investigated range of 50–80% WHCmax. Conclusions Almost all tested natural soil substrates allowed for root imaging using MRI. Half of these substrates resulted in root images comparable to our current lab standard substrate, allowing root detection down to a diameter of 300 µm. These soils were used as supplied by the vendor and, in particular, removal of ferromagnetic particles was not necessary. With the characterization of different soils, investigations such as trait stability across substrates are now possible using noninvasive MRI.

  1. Multiple imaging procedures including MRI for the bladder cancer

    International Nuclear Information System (INIS)

    Mikata, Noriharu; Suzuki, Makoto; Takeuchi, Takumi; Kunisawa, Yositaka; Fukutani, Keiko; Kawabe, Kazuki

    1986-01-01

    Endoscopic photography, double contrast cystography, transurethral echography, X-ray CT scan, and MRI (magnetic resonance imaging) were utilized for the staging diagnosis of the four patients with carcinoma of the bladder. In the first case, a 70-year-old man, since all of the five imaging procedures suggested a superficial and pedunculated tumor, his bladder cancer was considered T1. The classification of stage T3 carcinoma was made for the second 86-year-old male. Because all of his imaging examinations showed a tumor infiltrating deep muscle and penetrating the bladder wall. The third case was a 36-year-old male. His clinical stage was diagnosed as T2 or T3a by cystophotography, double contrast cystogram, ultrasonography, and X-ray CT scan. However, MRI showed only thickened bladder wall and the infiltrating tumor could not be distinguished from the hypertrophic wall. The last patient, a 85-year-old female, had a smaller Ta cancer. Her double contrast cystography revealed the small tumor at the lateral bladder wall. But, the tumor could not be detected by transaxial, sagittal and coronal scans. Multiple imaging procedures combining MRI and staging diagnosis of the bladder carcinoma were discussed. (author)

  2. Wavelet-based de-noising algorithm for images acquired with parallel magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Delakis, Ioannis; Hammad, Omer; Kitney, Richard I

    2007-01-01

    Wavelet-based de-noising has been shown to improve image signal-to-noise ratio in magnetic resonance imaging (MRI) while maintaining spatial resolution. Wavelet-based de-noising techniques typically implemented in MRI require that noise displays uniform spatial distribution. However, images acquired with parallel MRI have spatially varying noise levels. In this work, a new algorithm for filtering images with parallel MRI is presented. The proposed algorithm extracts the edges from the original image and then generates a noise map from the wavelet coefficients at finer scales. The noise map is zeroed at locations where edges have been detected and directional analysis is also used to calculate noise in regions of low-contrast edges that may not have been detected. The new methodology was applied on phantom and brain images and compared with other applicable de-noising techniques. The performance of the proposed algorithm was shown to be comparable with other techniques in central areas of the images, where noise levels are high. In addition, finer details and edges were maintained in peripheral areas, where noise levels are low. The proposed methodology is fully automated and can be applied on final reconstructed images without requiring sensitivity profiles or noise matrices of the receiver coils, therefore making it suitable for implementation in a clinical MRI setting

  3. Degeneration of pyramidal tract of MRI (magnetic resonance imaging)

    International Nuclear Information System (INIS)

    Yamagami, Tatsuhito; Harada, Noboru; Gotoh, Yasunobu; Imataka, Kiyoharu; Kinuta, Yuji; Okumura, Teizo; Niijima, Kyo; Taki, Waro; Kikuchi, Haruhiko.

    1988-01-01

    MRI (magnetic resonance imaging) examinaion was performed on cases of hemiplegia and hemiparesis. These included seven cases of intracerebral hemorrhage, four cases of subarachnoid hemorrhage, one case of cerebral infarct, and two cases of head trauma. The pyramidal tract in the brain stem was studied in five patients with complete hemiplegia and in nine with incomplete hemiparesis. The scanner of the MRI was a resistive type operating at a field of 0.2 Tesla. The inversion recovery (IR) and saturation recovery (SR) techniques were utilized. The pyramidal tract at the level of the midbrain and the pons was recognized as a low intensity area on the T 1 image (IR 1500/43) in the cases of complete hemiplegia. However, it was recognized as a high intensity area on the SR image (SR 1000/60) and the T 2 image (SR 2000/100). No abnormal signal intensity was found in the cases of incomplete hemiparesis. A low intensity area on the T 1 image and a high intensity area on the T 2 image were recognized in the ventral portion of the midbrain and the pons on the affected side. These findings indicate a degeneration of the pyramidal tract at the level of the brain stem in patients with complete hemiplegia. (author)

  4. Accelerated Fractional Ventilation Imaging with Hyperpolarized Gas MRI

    Science.gov (United States)

    Emami, Kiarash; Xu, Yinan; Hamedani, Hooman; Profka, Harrilla; Kadlecek, Stephen; Xin, Yi; Ishii, Masaru; Rizi, Rahim R.

    2013-01-01

    PURPOSE To investigate the utility of accelerated imaging to enhance multi-breath fractional ventilation (r) measurement accuracy using HP gas MRI. Undersampling shortens the breath-hold time, thereby reducing the O2-induced signal decay and allows subjects to maintain a more physiologically relevant breathing pattern. Additionally it may improve r estimation accuracy by reducing RF destruction of HP gas. METHODS Image acceleration was achieved by using an 8-channel phased array coil. Undersampled image acquisition was simulated in a series of ventilation images and images were reconstructed for various matrix sizes (48–128) using GRAPPA. Parallel accelerated r imaging was also performed on five mechanically ventilated pigs. RESULTS Optimal acceleration factor was fairly invariable (2.0–2.2×) over the range of simulated resolutions. Estimation accuracy progressively improved with higher resolutions (39–51% error reduction). In vivo r values were not significantly different between the two methods: 0.27±0.09, 0.35±0.06, 0.40±0.04 (standard) versus 0.23±0.05, 0.34±0.03, 0.37±0.02 (accelerated); for anterior, medial and posterior slices, respectively, whereas the corresponding vertical r gradients were significant (P fractional ventilation measurement with HP gas MRI. PMID:23400938

  5. Functional MRI studies of human vision on a clinical imager

    International Nuclear Information System (INIS)

    George, J.S.; Lewine, J.D.; Aine, C.J.; van Hulsteyn, D.; Wood, C.C.; Sanders, J.; Maclin, E.; Belliveau, J.W.; Caprihan, A.

    1992-01-01

    During the past decade, Magnetic Resonance Imaging (MRI) has become the method of choice for imaging the anatomy of the human brain. Recently, Belliveau and colleagues have reported the use of echo planar magnetic resonance imaging (EPI) to image patterns of neural activity. Here, we report functional MR imaging in response to visual stimulation without the use of contrast agents, and without the extensive hardware modifications required for EPI. Regions of activity were observed near the expected locations of V1, V2 and possibly V3 and another active region was observed near the parietal-occipital sulcus on the superior surface of the cerebrum. These locations are consistent with sources observed in neuromagnetic studies of the human visual response

  6. Editorial Commentary: Single-Image Slice Magnetic Resonance Imaging Assessments Do Not Predict 3-Dimensional Muscle Volume.

    Science.gov (United States)

    Brand, Jefferson C

    2016-01-01

    No single-image magnetic resonance imaging (MRI) assessment-Goutallier classification, Fuchs classification, or cross-sectional area-is predictive of whole-muscle volume or fatty atrophy of the supraspinatus or infraspinatus. Rather, 3-dimensional MRI measurement of whole-muscle volume and fat-free muscle volume is required and is associated with shoulder strength, which is clinically relevant. Three-dimensional MRI may represent a new gold standard for assessment of the rotator cuff musculature using imaging and may help to predict the feasibility of repair of a rotator cuff tear as well as the postoperative outcome. Unfortunately, 3-dimensional MRI assessment of muscle volume is labor intensive and is not widely available for clinical use. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  7. Wavelet-space correlation imaging for high-speed MRI without motion monitoring or data segmentation.

    Science.gov (United States)

    Li, Yu; Wang, Hui; Tkach, Jean; Roach, David; Woods, Jason; Dumoulin, Charles

    2015-12-01

    This study aims to (i) develop a new high-speed MRI approach by implementing correlation imaging in wavelet-space, and (ii) demonstrate the ability of wavelet-space correlation imaging to image human anatomy with involuntary or physiological motion. Correlation imaging is a high-speed MRI framework in which image reconstruction relies on quantification of data correlation. The presented work integrates correlation imaging with a wavelet transform technique developed originally in the field of signal and image processing. This provides a new high-speed MRI approach to motion-free data collection without motion monitoring or data segmentation. The new approach, called "wavelet-space correlation imaging", is investigated in brain imaging with involuntary motion and chest imaging with free-breathing. Wavelet-space correlation imaging can exceed the speed limit of conventional parallel imaging methods. Using this approach with high acceleration factors (6 for brain MRI, 16 for cardiac MRI, and 8 for lung MRI), motion-free images can be generated in static brain MRI with involuntary motion and nonsegmented dynamic cardiac/lung MRI with free-breathing. Wavelet-space correlation imaging enables high-speed MRI in the presence of involuntary motion or physiological dynamics without motion monitoring or data segmentation. © 2014 Wiley Periodicals, Inc.

  8. Magnetic Resonance Imaging (MRI and Spectroscopy (MRS in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Uma Sharma

    2008-01-01

    Full Text Available Breast cancer is a major health problem in women and early detection is of prime importance. Breast magnetic resonance imaging (MRI provides both physical and physiologic tissue features that are useful in discriminating malignant from benign lesions. Contrast enhanced MRI is valuable for diagnosis of small tumors in dense breast and the structural and kinetic parameters improved the specificity of diagnosing benign from malignant lesions. It is a complimentary modality for preoperative staging, to follow response to therapy, to detect recurrences and for screening high risk women. Diffusion, perfusion and MR elastography have been applied to breast lesion characterization and show promise.In-vivo MR spectroscopy (MRS is a valuable method to obtain the biochemical status of normal and diseased tissues. Malignant tissues contain high concentration of choline containing compounds that can be used as a biochemical marker. MRS helps to increase the specificity of MRI in lesions larger than 1cm and to monitor the tumor response. Various MR techniques show promise primarily as adjunct to the existing standard detection techniques, and its acceptability as a screening method will increase if specificity can be improved. This review presents the progress made in different MRI and MRS techniques in breast cancer management.

  9. Magnetic Resonance Imaging (MRI and Spectroscopy (MRS in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Uma Sharma

    2008-01-01

    Full Text Available Breast cancer is a major health problem in women and early detection is of prime importance. Breast magnetic resonance imaging (MRI provides both physical and physiologic tissue features that are useful in discriminating malignant from benign lesions. Contrast enhanced MRI is valuable for diagnosis of small tumors in dense breast and the structural and kinetic parameters improved the specificity of diagnosing benign from malignant lesions. It is a complimentary modality for preoperative staging, to follow response to therapy, to detect recurrences and for screening high risk women. Diffusion, perfusion and MR elastography have been applied to breast lesion characterization and show promise. In-vivo MR spectroscopy (MRS is a valuable method to obtain the biochemical status of normal and diseased tissues. Malignant tissues contain high concentration of choline containing compounds that can be used as a biochemical marker. MRS helps to increase the specificity of MRI in lesions larger than 1cm and to monitor the tumor response. Various MR techniques show promise primarily as adjunct to the existing standard detection techniques, and its acceptability as a screening method will increase if specificity can be improved. This review presents the progress made in different MRI and MRS techniques in beast cancer management.

  10. Comparison of Diffusion-Weighted Imaging in the Human Brain Using Readout-Segmented EPI and PROPELLER Turbo Spin Echo With Single-Shot EPI at 7 T MRI.

    Science.gov (United States)

    Kida, Ikuhiro; Ueguchi, Takashi; Matsuoka, Yuichiro; Zhou, Kun; Stemmer, Alto; Porter, David

    2016-07-01

    The purpose of the present study was to compare periodically rotated overlapping parallel lines with enhanced reconstruction-type turbo spin echo diffusion-weighted imaging (pTSE-DWI) and readout-segmented echo planar imaging (rsEPI-DWI) with single-shot echo planar imaging (ssEPI-DWI) in a 7 T human MR system. We evaluated the signal-to-noise ratio (SNR), image distortion, and apparent diffusion coefficient values in the human brain. Six healthy volunteers were included in this study. The study protocol was approved by our institutional review board. All measurements were performed at 7 T using pTSE-DWI, rsEPI-DWI, and ssEPI-DWI sequences. The spatial resolution was 1.2 × 1.2 mm in-plane with a 3-mm slice thickness. Signal-to-noise ratio was measured using 2 scans. The ssEPI-DWI sequence showed significant image blurring, whereas pTSE-DWI and rsEPI-DWI sequences demonstrated high image quality with low geometrical distortion compared with reference T2-weighted, turbo spin echo images. Signal loss in ventral regions near the air-filled paranasal sinus/nasal cavity was found in ssEPI-DWI and rsEPI-DWI but not pTSE-DWI. The apparent diffusion coefficient values for ssEPI-DWI were 824 ± 17 × 10 and 749 ± 25 × 10 mm/s in the gray matter and white matter, respectively; the values obtained for pTSE-DWI were 798 ± 21 × 10 and 865 ± 40 × 10 mm/s; and the values obtained for rsEPI-DWI were 730 ± 12 × 10 and 722 ± 25 × 10 mm/s. The pTSE-DWI images showed no additional distortion comparison to the T2-weighted images, but had a lower SNR than ssEPI-DWI and rsEPI-DWI. The rsEPI-DWI sequence provided high-quality images with minor distortion and a similar SNR to ssEPI-DWI. Our results suggest that the benefits of the rsEPI-DWI and pTSE-DWI sequences, in terms of SNR, image quality, and image distortion, appear to outweigh those of ssEPI-DWI. Thus, pTSE-DWI and rsEPI-DWI at 7 T have great potential use for clinical diagnoses. However, it is noteworthy that both

  11. Complete Fourier Direct Magnetic Resonance Imaging (CFD-MRI for Diffusion MRI

    Directory of Open Access Journals (Sweden)

    Alpay eÖzcan

    2013-04-01

    Full Text Available The foundation for an accurate and unifying Fourier based theory of diffusion weighted magnetic resonance imaging (DW-MRI is constructed by carefully re-examining the first principles of DW-MRI signal formation and deriving its mathematical model from scratch. The derivations are specifically obtained for DW-MRI signal by including all of its elements (e.g., imaging gradients using complex values. Particle methods are utilized in contrast to conventional partial differential equations approach. The signal is shown to be the Fourier transform of the joint distribution of number of the magnetic moments (at a given location at the initial time and magnetic moment displacement integrals. In effect, the k-space is augmented by three more dimensions, corresponding to the frequency variables dual to displacement integral vectors. The joint distribution function is recovered by applying the Fourier transform to the complete high-dimensional data set. In the process, to obtain a physically meaningful real valued distribution function, phase corrections are applied for the re-establishment of Hermitian symmetry in the signal. Consequently, the method is fully unconstrained and directly presents the distribution of displacement integrals without any assumptions such as symmetry or Markovian property. The joint distribution function is visualized with isosurfaces, which describe the displacement integrals, overlaid on the distribution map of the number of magnetic moments with low mobility. The model provides an accurate description of the molecular motion measurements via DW-MRI. The improvement of the characterization of tissue microstructure leads to a better localization, detection and assessment of biological properties such as white matter integrity. The results are demonstrated on the experimental data obtained from an ex-vivo baboon brain.

  12. Image reconstruction of dynamic infrared single-pixel imaging system

    Science.gov (United States)

    Tong, Qi; Jiang, Yilin; Wang, Haiyan; Guo, Limin

    2018-03-01

    Single-pixel imaging technique has recently received much attention. Most of the current single-pixel imaging is aimed at relatively static targets or the imaging system is fixed, which is limited by the number of measurements received through the single detector. In this paper, we proposed a novel dynamic compressive imaging method to solve the imaging problem, where exists imaging system motion behavior, for the infrared (IR) rosette scanning system. The relationship between adjacent target images and scene is analyzed under different system movement scenarios. These relationships are used to build dynamic compressive imaging models. Simulation results demonstrate that the proposed method can improve the reconstruction quality of IR image and enhance the contrast between the target and the background in the presence of system movement.

  13. Clinical use of digital retrospective image fusion of CT, MRI, FDG-PET and SPECT - fields of indications and results

    International Nuclear Information System (INIS)

    Lemke, A.J.; Niehues, S.M.; Amthauer, H.; Felix, R.; Rohlfing, T.; Hosten, N.

    2004-01-01

    Purpose: To evaluate the feasibility and the clinical benefits of retrospective digital image fusion (PET, SPECT, CT and MRI). Materials and methods: In a prospective study, a total of 273 image fusions were performed and evaluated. The underlying image acquisitions (CT, MRI, SPECT and PET) were performed in a way appropriate for the respective clinical question and anatomical region. Image fusion was executed with a software program developed during this study. The results of the image fusion procedure were evaluated in terms of technical feasibility, clinical objective, and therapeutic impact. Results: The most frequent combinations of modalities were CT/PET (n = 156) and MRI/PET (n = 59), followed by MRI/SPECT (n = 28), CT/SPECT (n = 22) and CT/MRI (n = 8). The clinical questions included following regions (more than one region per case possible): neurocranium (n = 42), neck (n = 13), lung and mediastinum (n = 24), abdomen (n = 181), and pelvis (n = 65). In 92.6% of all cases (n = 253), image fusion was technically successful. Image fusion was able to improve sensitivity and specificity of the single modality, or to add important diagnostic information. Image fusion was problematic in cases of different body positions between the two imaging modalities or different positions of mobile organs. In 37.9% of the cases, image fusion added clinically relevant information compared to the single modality. Conclusion: For clinical questions concerning liver, pancreas, rectum, neck, or neurocranium, image fusion is a reliable method suitable for routine clinical application. Organ motion still limits its feasibility and routine use in other areas (e.g., thorax). (orig.)

  14. CT and MRI imaging of the brain in MELAS syndrome.

    Science.gov (United States)

    Pauli, Wojciech; Zarzycki, Artur; Krzyształowski, Adam; Walecka, Anna

    2013-07-01

    MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) is a rare, multisystem disorder which belongs to a group of mitochondrial metabolic diseases. As other diseases in this group, it is inherited in the maternal line. In this report, we discussed a case of a 10-year-old girl with clinical and radiological picture of MELAS syndrome. We would like to describe characteristic radiological features of MELAS syndrome in CT, MRI and MR spectroscopy of the brain and differential diagnosis. The rarity of this disorder and the complexity of its clinical presentation make MELAS patients among the most difficult to diagnose. Brain imaging studies require a wide differential diagnosis, primarily to distinguish between MELAS and ischemic stroke. Particularly helpful are the MRI and MR spectroscopy techniques.

  15. CT and MRI imaging of the brain in MELAS syndrome

    International Nuclear Information System (INIS)

    Pauli, Wojciech; Zarzycki, Artur; Krzyształowski, Adam; Walecka, Anna

    2013-01-01

    MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, stroke-like episodes) is a rare, multisystem disorder which belongs to a group of mitochondrial metabolic diseases. As other diseases in this group, it is inherited in the maternal line. In this report, we discussed a case of a 10-year-old girl with clinical and radiological picture of MELAS syndrome. We would like to describe characteristic radiological features of MELAS syndrome in CT, MRI and MR spectroscopy of the brain and differential diagnosis. The rarity of this disorder and the complexity of its clinical presentation make MELAS patients among the most difficult to diagnose. Brain imaging studies require a wide differential diagnosis, primarily to distinguish between MELAS and ischemic stroke. Particularly helpful are the MRI and MR spectroscopy techniques

  16. MRI-negative refractory partial epilepsy: role for diffusion tensor imaging in high field MRI.

    Science.gov (United States)

    Chen, Qin; Lui, Su; Li, Chun-Xiao; Jiang, Li-Jun; Ou-Yang, Luo; Tang, He-Han; Shang, Hui-Fang; Huang, Xiao-Qi; Gong, Qi-Yong; Zhou, Dong

    2008-07-01

    Our aim is to use the high field MR scanner (3T) to verify whether diffusion tensor imaging (DTI) could help in locating the epileptogenic zone in patients with MRI-negative refractory partial epilepsy. Fifteen patients with refractory partial epilepsy who had normal conventional MRI, and 40 healthy volunteers were recruited for the study. DTI was performed on a 3T MR scanner, individual maps of mean diffusivity (MD) and fractional anisotropy (FA) were calculated, and Voxel-Based Analysis (VBA) was performed for individual comparison between patients and controls. Voxel-based analysis revealed significant MD increase in variant regions in 13 patients. The electroclinical seizure localization was concurred to seven patients. No patient exhibited regions of significant decreased MD. Regions of significant reduced FA were observed in five patients, with two of these concurring with electroclinical seizure localization. Two patients had regions of significant increase in FA, which were distinct from electroclinical seizure localization. Our study's results revealed that DTI is a responsive neuroradiologic technique that provides information about the epileptogenic areas in patients with MRI-negative refractory partial epilepsy. This technique may also helpful in pre-surgical evaluation.

  17. Generalized INverse imaging (GIN): ultrafast fMRI with physiological noise correction.

    Science.gov (United States)

    Boyacioğlu, Rasim; Barth, Markus

    2013-10-01

    An ultrafast functional magnetic resonance imaging (fMRI) technique, called generalized inverse imaging (GIN), is proposed, which combines inverse imaging with a phase constraint-leading to a less underdetermined reconstruction-and physiological noise correction. A single 3D echo planar imaging (EPI) prescan is sufficient to obtain the necessary coil sensitivity information and reference images that are used to reconstruct standard images, so that standard analysis methods are applicable. A moving dots stimulus paradigm was chosen to assess the performance of GIN. We find that the spatial localization of activation for GIN is comparable to an EPI protocol and that maximum z-scores increase significantly. The high temporal resolution of GIN (50 ms) and the acquisition of the phase information enable unaliased sampling and regression of physiological signals. Using the phase time courses obtained from the 32 channels of the receiver coils as nuisance regressors in a general linear model results in significant improvement of the functional activation, rendering the acquisition of external physiological signals unnecessary. The proposed physiological noise correction can in principle be used for other fMRI protocols, such as simultaneous multislice acquisitions, which acquire the phase information sufficiently fast and sample physiological signals unaliased. Copyright © 2012 Wiley Periodicals, Inc.

  18. Fully refocused multi-shot spatiotemporally encoded MRI: robust imaging in the presence of metallic implants.

    Science.gov (United States)

    Ben-Eliezer, Noam; Solomon, Eddy; Harel, Elad; Nevo, Nava; Frydman, Lucio

    2012-12-01

    An approach has been recently introduced for acquiring arbitrary 2D NMR spectra or images in a single scan, based on the use of frequency-swept RF pulses for the sequential excitation and acquisition of the spins response. This spatiotemporal-encoding (SPEN) approach enables a unique, voxel-by-voxel refocusing of all frequency shifts in the sample, for all instants throughout the data acquisition. The present study investigates the use of this full-refocusing aspect of SPEN-based imaging in the multi-shot MRI of objects, subject to sizable field inhomogeneities that complicate conventional imaging approaches. 2D MRI experiments were performed at 7 T on phantoms and on mice in vivo, focusing on imaging in proximity to metallic objects. Fully refocused SPEN-based spin echo imaging sequences were implemented, using both Cartesian and back-projection trajectories, and compared with k-space encoded spin echo imaging schemes collected on identical samples under equal bandwidths and acquisition timing conditions. In all cases assayed, the fully refocused spatiotemporally encoded experiments evidenced a ca. 50 % reduction in signal dephasing in the proximity of the metal, as compared to analogous results stemming from the k-space encoded spin echo counterparts. The results in this study suggest that SPEN-based acquisition schemes carry the potential to overcome strong field inhomogeneities, of the kind that currently preclude high-field, high-resolution tissue characterizations in the neighborhood of metallic implants.

  19. Heroin-induced leukoencephalopathy: characterization using MRI, diffusion-weighted imaging, and MR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Offiah, C. [Department of Neuroradiology, St Bartholomew' s and the London Hospitals NHS Trust, London (United Kingdom); Hall, E. [Department of Neuroradiology, St Bartholomew' s and the London Hospitals NHS Trust, London (United Kingdom)], E-mail: curtis.offiah@bartsandthelondon.nhs.uk

    2008-02-15

    Aim: To describe the magnetic resonance imaging (MRI) characteristics of heroin-induced leukoencephalopathy or 'chasing the dragon syndrome' and, in particular, the diffusion-weighted imaging (DWI) and MR spectroscopy (MRS) features. Material and methods: Six patients with a clinical or histopathological diagnosis of heroin-induced leukoencephalopathy were identified and MRI examinations, including DWI and single-voxel MRS, reviewed. Results: Cerebellar white matter was involved in all six cases demonstrating similar symmetrical distribution with sparing of the dentate nuclei. Brain stem signal change was evident in five of the six patients imaged. Supratentorial brain parenchymal involvement, as well as brain stem involvement, correlated anatomically with corticospinal tract distribution. None of the areas of signal abnormality were restricted on DWI. Of those patients subjected to MRS, the areas of parenchymal damage demonstrated reduced N-acetylaspartate, reduced choline, and elevated lactate. Conclusion: Heroin-induced leukoencephalopathy results in characteristic and highly specific signal abnormalities on MRI, which can greatly aid diagnosis. DWI and MRS findings can be explained by known reported neuropathological descriptions in this condition and can be used to support a proposed mechanism for the benefit of current recommended drug treatment regimes.

  20. Automatic delineation of brain regions on MRI and PET images from the pig

    DEFF Research Database (Denmark)

    Villadsen, Jonas; Hansen, Hanne D; Jørgensen, Louise M

    2018-01-01

    : Manual inter-modality spatial normalization to a MRI atlas is operator-dependent, time-consuming, and can be inaccurate with lack of cortical radiotracer binding or skull uptake. NEW METHOD: A parcellated PET template that allows for automatic spatial normalization to PET images of any radiotracer....... RESULTS: MRI and [11C]Cimbi-36 PET scans obtained in sixteen pigs made the basis for the atlas. The high resolution MRI scans allowed for creation of an accurately averaged MRI template. By aligning the within-subject PET scans to their MRI counterparts, an averaged PET template was created in the same...... the MRI template with individual MRI images and 0.92±0.26mm using the PET template with individual [11C]Cimbi-36 PET images. We tested the automatic procedure by assessing eleven PET radiotracers with different kinetics and spatial distributions by using perfusion-weighted images of early PET time frames...

  1. Imaging of acute myocardial infarction in pigs with Indium-111 monoclonal antimyosin scintigraphy and MRI

    International Nuclear Information System (INIS)

    Kate, C.I.; Kroonenburgh, M.J. van; Schipperheyn, J.J.; Doornbos, J.; Hoedemaeker, P.J.; Maes, A.; Nat, K.H. van der; Camps, J.A.; Huysmans, H.A.; Pauwels, E.K.

    1990-01-01

    Indium-111 antimyosin F(ab')2 was used in a series of scintigraphic studies on experimentally induced myocardial infarctions in pigs. Antimyosin distribution recorded by planar images of in vivo pigs and by single photon emission computed tomography (SPECT) of excised hearts delineated areas of myocardial necrosis if infarct volume exceeded 3.3 cm3. Scintigraphic images were compared with magnetic resonance images (MRI) obtained from excised hearts and with photographs of slices of the hearts. Infarct size and localization determined with antimyosin were compared. The MR images, with or without gadolinium-DTPA (Gd-DTPA), of the in vivo pigs were all false-negative; some myocardial wall thinning and high bloodpool signals were visible. Results show that both the antimyosin and the MR technique are specific methods for the visualization of induced myocardial necrosis in this animal model. However, the use of antimyosin is limited to a period ranging from 24 to 72 hours after infarction

  2. Paediatrics brain imaging in epilepsy: common presenting symptoms and spectrum of abnormalities detected on MRI

    International Nuclear Information System (INIS)

    Ali, A.; Akram, F.; Khan, G.; Hussain, S.

    2017-01-01

    Epilepsy, a common neurological disorder can present at any age and has a number of aetiologies with underlying brain disease being the most common aetiology. Brain imaging becomes important and mandatory in the work up for epilepsy in localization and lateralization of the seizure focus. Methods: This cross-sectional study was conducted in the department of Radiology Ayub Medical Teaching Institution Abbottabad from 1st March 2015 to 31st March 2016. A total of 209 children aged 28 days to 14 years were included in the study who presented with seizures to clinicians. Information obtained from history, clinical examination and investigations especially MRI brains were recorded in a prescribed pro forma. The data was analysed in SPSS 20. Results: MRI examination was unremarkable in 44.01% (n=92) and mild generalized brain atrophy was noted in 12.91% (n=27). Arachnoid cysts, mild unilateral brain atrophy and hydrocephalous due to aqueduct stenosis were recorded in 3.82% (n=8) of each group. Neoplastic lesions were the second most common abnormal MRI finding and constituted 5.74% (n=12). Leukodystrophy was diagnosed in 4.78% (n=10). MRI examination showed ring enhancing lesions (tuberculomas) and AVM in 1.43% (n=3) of each group. Perinatal ischemia and intracranial infection, (focal or generalized) were recorded in 2.87% (n=6) of each group. A 0.95 % (n=2) of children in each group had agenesis of corpus callosum and cavernoma. The radiological MRI diagnosis of Raussmussen encephalitis was made in 3.34% (n=7). Single case, each of mesial temporal sclerosis, subdural haemorrhage, infarct and craniopharyngioma was recorded making 0.47 % of the total patients in each case. Conclusion: MRI examination was abnormal in significant number of patients (55.86%), so therefore if properly utilized, in a good clinical context, this can identify most of the structural brain abnormalities in paediatric patients presenting with seizures. (author)

  3. Edge-oriented dual-dictionary guided enrichment (EDGE) for MRI-CT image reconstruction.

    Science.gov (United States)

    Li, Liang; Wang, Bigong; Wang, Ge

    2016-01-01

    In this paper, we formulate the joint/simultaneous X-ray CT and MRI image reconstruction. In particular, a novel algorithm is proposed for MRI image reconstruction from highly under-sampled MRI data and CT images. It consists of two steps. First, a training dataset is generated from a series of well-registered MRI and CT images on the same patients. Then, an initial MRI image of a patient can be reconstructed via edge-oriented dual-dictionary guided enrichment (EDGE) based on the training dataset and a CT image of the patient. Second, an MRI image is reconstructed using the dictionary learning (DL) algorithm from highly under-sampled k-space data and the initial MRI image. Our algorithm can establish a one-to-one correspondence between the two imaging modalities, and obtain a good initial MRI estimation. Both noise-free and noisy simulation studies were performed to evaluate and validate the proposed algorithm. The results with different under-sampling factors show that the proposed algorithm performed significantly better than those reconstructed using the DL algorithm from MRI data alone.

  4. Content Based Medical Image Retrieval for Histopathological, CT and MRI Images

    Directory of Open Access Journals (Sweden)

    Swarnambiga AYYACHAMY

    2013-09-01

    Full Text Available A content based approach is followed for medical images. The purpose of this study is to access the stability of these methods for medical image retrieval. The methods used in color based retrieval for histopathological images are color co-occurrence matrix (CCM and histogram with meta features. For texture based retrieval GLCM (gray level co-occurrence matrix and local binary pattern (LBP were used. For shape based retrieval canny edge detection and otsu‘s method with multivariable threshold were used. Texture and shape based retrieval were implemented using MRI (magnetic resonance images. The most remarkable characteristics of the article are its content based approach for each medical imaging modality. Our efforts were focused on the initial visual search. From our experiment, histogram with meta features in color based retrieval for histopathological images shows a precision of 60 % and recall of 30 %. Whereas GLCM in texture based retrieval for MRI images shows a precision of 70 % and recall of 20 %. Shape based retrieval for MRI images shows a precision of 50% and recall of 25 %. The retrieval results shows that this simple approach is successful.

  5. Trends in magnetic resonance imaging. Technical trends in MRI, noise reduction and fast imaging

    International Nuclear Information System (INIS)

    Sugimoto, Hiroshi

    2007-01-01

    At MRI examination, patients suffer the machine noise and long tight lying as well as an oppressive feeling. This paper describes the technological efforts against the former two. The noise is generated from the force (thumb-ward) to vibrate the magnetic field gradient coil according to the left-hand rule. Authors have developed a MRI machine (Pianissimo) where the coil is placed in vacuum and its actual noise level is found reduced from 105 - 112 to 84 dB(A) at 1.5T. Fast imaging to shorten the imaging time is attained by combination of parallel imaging where MR signals are into multiple high frequency receiver coils, and the usual pulse sequence imaging, which results in the increased encoding in a given time. Together with these, MR angiography and diffusion weighted imaging of abdomen for cancer examination are becoming popular as an additional MRI diagnosis, also acceptable to patients. Future progress of MRI machines conceivably accompanies the unavoidable noise increase and possibly significant magnetic effects on human body, and efforts for their reduction will be continued at patients' viewpoint. (T.I.)

  6. Diagnostic imaging in 13 cases of Rasmussen's encephalitis. Can early MRI suggest the diagnosis?

    International Nuclear Information System (INIS)

    Chiapparini, L.; Farina, L.; Ciceri, E.; Erbetta, A.; Savoiardo, M.; Granata, T.; Ragona, F.; Freri, E.; Fusco, L.; Gobbi, G.; Capovilla, G.; Tassi, L.; Viri, M.; Giordano, L.; Bernardina, B.D.; Spreafico, R.

    2003-01-01

    Rasmussen's encephalitis (RE) is a rare, progressive, chronic encephalitis characterised by drug-resistant epilepsy, progressive hemiparesis and mental impairment. It typically involves only one cerebral hemisphere, which becomes atrophic. We present neuroradiological findings in 13 children with RE. MRI was performed in all patients, fluorodeoxyglucose positron-emission tomography (PET) in three, Tc-99m hexamethylpropylenamine oxime single-photon emission computed tomography (SPECT) in two and proton MR spectroscopy ( 1 HMRS) in two. MRI showed progression of the hemisphere atrophy, always prevalent in the region primarily involved (13 patients), spread of the abnormal signal in white matter (11) and cortex (10) and progression of atrophy of the head of the caudate nucleus (nine). Associated secondary changes were: atrophy of the contralateral cerebellar hemisphere (in four patients), the ipsilateral hippocampus (in five) and the brain stem (in five). The earliest CT and MRI abnormalities, seen between 1 day and 4 months after the first seizure (in 12 patients examined, nine of whom had MRI) in one cerebral hemisphere included: high signal on T2-weighted images in the cortex (seven patients) and white matter (nine), cortical atrophy usually involving the frontoinsular region, with mild or severe enlargement of the lateral ventricle (eight) and moderate atrophy of the head of the caudate nucleus (seven). (orig.)

  7. Automated imaging system for single molecules

    Science.gov (United States)

    Schwartz, David Charles; Runnheim, Rodney; Forrest, Daniel

    2012-09-18

    There is provided a high throughput automated single molecule image collection and processing system that requires minimal initial user input. The unique features embodied in the present disclosure allow automated collection and initial processing of optical images of single molecules and their assemblies. Correct focus may be automatically maintained while images are collected. Uneven illumination in fluorescence microscopy is accounted for, and an overall robust imaging operation is provided yielding individual images prepared for further processing in external systems. Embodiments described herein are useful in studies of any macromolecules such as DNA, RNA, peptides and proteins. The automated image collection and processing system and method of same may be implemented and deployed over a computer network, and may be ergonomically optimized to facilitate user interaction.

  8. Simultaneous functional imaging using fPET and fMRI

    Energy Technology Data Exchange (ETDEWEB)

    Villien, Marjorie [CERMEP (France)

    2015-05-18

    Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

  9. Simultaneous functional imaging using fPET and fMRI

    International Nuclear Information System (INIS)

    Villien, Marjorie

    2015-01-01

    Brain mapping of task-associated changes in metabolism with PET has been accomplished by subtracting scans acquired during two distinct static states. We have demonstrated that PET can provide truly dynamic information on cerebral energy metabolism using constant infusion of FDG and multiple stimuli in a single experiment. We demonstrate here that the functional PET (fPET-FDG) method accomplished simultaneously with fMRI, can enable the first direct comparisons in time, space and magnitude of hemodynamics and oxygen and glucose consumption. The imaging studies were performed on a 3T Tim-Trio MR scanner modified to support an MR-compatible BrainPET insert. Ten healthy subjects were included. The total PET acquisition and infusion time was 90 minutes. We did 3 blocks of right hand fingers tapping for 10 minutes at 30, 50 and 70 minutes after the beginning of the PET acquisition. ASL and BOLD imaging were acquired simultaneously during the motor paradigm. Changes in glucose utilization are easily observed as changes in the TAC slope of the PET data (FDG utilization rate) and in the derivative signal during motor stimuli in the activated voxels. PET and MRI (ASL, and BOLD) activations are largely colocalized but with very different statistical significance and temporal dynamic, especially in the ipsilateral side of the stimuli. This study demonstrated that motor activation can be measured dynamically during a single FDG PET scan. The complementary nature of fPET-FDG to fMRI capitalizes on the emerging technology of hybrid MR-PET scanners. fPET-FDG, combined with quantitative fMRI methods, allow us to simultaneously measure dynamic changes in glucose utilization and hemodynamic, addressing vital questions about neurovascular coupling.

  10. Magnetic resonance imaging (MRI) of primary liver cancer

    International Nuclear Information System (INIS)

    Ohtomo, Kuni; Itai, Yuji; Furui, Shigeru; Yoshikawa, Kohki; Yashiro, Naobumi; Iio, Masahiro

    1985-01-01

    In seven primary liver cancers (HCC 5, CCC 1, mixed 1), MR images (0.35 Tesla superconducting) were compared with macroscopic appearances, and relaxation times (T 1 and T 2 ) with microscopic characteristics. MRI was able to reveal the gross appearance of five nodular lesions, but did not reveal one diffuse HCC and one nodular HCC with marked extracapsular extension. T 2 -weighted SE images could not demonstrate fibrous capsules around the tumor in four nodular HCCs. The T 1 and T 2 values of the tumors were longer than those of the surrounding liver parenchyma, and the T 1 elongation corresponded roughly to the degree of necrosis and fibrosis within the tumors. (author)

  11. A simple method for detecting tumor in T2-weighted MRI brain images. An image-based analysis

    International Nuclear Information System (INIS)

    Lau, Phooi-Yee; Ozawa, Shinji

    2006-01-01

    The objective of this paper is to present a decision support system which uses a computer-based procedure to detect tumor blocks or lesions in digitized medical images. The authors developed a simple method with a low computation effort to detect tumors on T2-weighted Magnetic Resonance Imaging (MRI) brain images, focusing on the connection between the spatial pixel value and tumor properties from four different perspectives: cases having minuscule differences between two images using a fixed block-based method, tumor shape and size using the edge and binary images, tumor properties based on texture values using spatial pixel intensity distribution controlled by a global discriminate value, and the occurrence of content-specific tumor pixel for threshold images. Measurements of the following medical datasets were performed: different time interval images, and different brain disease images on single and multiple slice images. Experimental results have revealed that our proposed technique incurred an overall error smaller than those in other proposed methods. In particular, the proposed method allowed decrements of false alarm and missed alarm errors, which demonstrate the effectiveness of our proposed technique. In this paper, we also present a prototype system, known as PCB, to evaluate the performance of the proposed methods by actual experiments, comparing the detection accuracy and system performance. (author)

  12. Ghost imaging with a single detector

    International Nuclear Information System (INIS)

    Bromberg, Yaron; Katz, Ori; Silberberg, Yaron

    2009-01-01

    We experimentally demonstrate pseudothermal ghost imaging and ghost diffraction using only a single detector. We achieve this by replacing the high-resolution detector of the reference beam with a computation of the propagating field, following a recent proposal by Shapiro [Phys. Rev. A 78, 061802(R) (2008)]. Since only a single detector is used, this provides experimental evidence that pseudothermal ghost imaging does not rely on nonlocal quantum correlations. In addition, we show the depth-resolving capability of this ghost imaging technique.

  13. Image fusion between whole body FDG PET images and whole body MRI images using a full-automatic mutual information-based multimodality image registration software

    International Nuclear Information System (INIS)

    Uchida, Yoshitaka; Nakano, Yoshitada; Fujibuchi, Toshiou; Isobe, Tomoko; Kazama, Toshiki; Ito, Hisao

    2006-01-01

    We attempted image fusion between whole body PET and whole body MRI of thirty patients using a full-automatic mutual information (MI) -based multimodality image registration software and evaluated accuracy of this method and impact of the coregistrated imaging on diagnostic accuracy. For 25 of 30 fused images in body area, translating gaps were within 6 mm in all axes and rotating gaps were within 2 degrees around all axes. In head and neck area, considerably much gaps caused by difference of head inclination at imaging occurred in 16 patients, however these gaps were able to decrease by fused separately. In 6 patients, diagnostic accuracy using PET/MRI fused images was superior compared by PET image alone. This work shows that whole body FDG PET images and whole body MRI images can be automatically fused using MI-based multimodality image registration software accurately and this technique can add useful information when evaluating FDG PET images. (author)

  14. Single-chip pulse programmer for magnetic resonance imaging using a 32-bit microcontroller.

    Science.gov (United States)

    Handa, Shinya; Domalain, Thierry; Kose, Katsumi

    2007-08-01

    A magnetic resonance imaging (MRI) pulse programmer has been developed using a single-chip microcontroller (ADmicroC7026). The microcontroller includes all the components required for the MRI pulse programmer: a 32-bit RISC CPU core, 62 kbytes of flash memory, 8 kbytes of SRAM, two 32-bit timers, four 12-bit DA converters, and 40 bits of general purpose I/O. An evaluation board for the microcontroller was connected to a host personal computer (PC), an MRI transceiver, and a gradient driver using interface circuitry. Target (embedded) and host PC programs were developed to enable MRI pulse sequence generation by the microcontroller. The pulse programmer achieved a (nominal) time resolution of approximately 100 ns and a minimum time delay between successive events of approximately 9 micros. Imaging experiments using the pulse programmer demonstrated the effectiveness of our approach.

  15. Software-based PET-MR image coregistration: combined PET-MRI for the rest of us

    International Nuclear Information System (INIS)

    Robertson, Matthew S.; Liu, Xinyang; Vyas, Pranav K.; Safdar, Nabile M.; Plishker, William; Zaki, George F.; Shekhar, Raj

    2016-01-01

    With the introduction of hybrid positron emission tomography/magnetic resonance imaging (PET/MRI), a new imaging option to acquire multimodality images with complementary anatomical and functional information has become available. Compared with hybrid PET/computed tomography (CT), hybrid PET/MRI is capable of providing superior anatomical detail while removing the radiation exposure associated with CT. The early adoption of hybrid PET/MRI, however, has been limited. To provide a viable alternative to the hybrid PET/MRI hardware by validating a software-based solution for PET-MR image coregistration. A fully automated, graphics processing unit-accelerated 3-D deformable image registration technique was used to align PET (acquired as PET/CT) and MR image pairs of 17 patients (age range: 10 months-21 years, mean: 10 years) who underwent PET/CT and body MRI (chest, abdomen or pelvis), which were performed within a 28-day (mean: 10.5 days) interval. MRI data for most of these cases included single-station post-contrast axial T1-weighted images. Following registration, maximum standardized uptake value (SUV max ) values observed in coregistered PET (cPET) and the original PET were compared for 82 volumes of interest. In addition, we calculated the target registration error as a measure of the quality of image coregistration, and evaluated the algorithm's performance in the context of interexpert variability. The coregistration execution time averaged 97±45 s. The overall relative SUV max difference was 7% between cPET-MRI and PET/CT. The average target registration error was 10.7±6.6 mm, which compared favorably with the typical voxel size (diagonal distance) of 8.0 mm (typical resolution: 0.66 mm x 0.66 mm x 8 mm) for MRI and 6.1 mm (typical resolution: 3.65 mm x 3.65 mm x 3.27 mm) for PET. The variability in landmark identification did not show statistically significant differences between the algorithm and a typical expert. We have presented a software

  16. Software-based PET-MR image coregistration: combined PET-MRI for the rest of us

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Matthew S.; Liu, Xinyang; Vyas, Pranav K.; Safdar, Nabile M. [Children' s National Health System, Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington, DC (United States); Plishker, William; Zaki, George F. [IGI Technologies, Inc., College Park, MD (United States); Shekhar, Raj [Children' s National Health System, Sheikh Zayed Institute for Pediatric Surgical Innovation, Washington, DC (United States); IGI Technologies, Inc., College Park, MD (United States)

    2016-10-15

    With the introduction of hybrid positron emission tomography/magnetic resonance imaging (PET/MRI), a new imaging option to acquire multimodality images with complementary anatomical and functional information has become available. Compared with hybrid PET/computed tomography (CT), hybrid PET/MRI is capable of providing superior anatomical detail while removing the radiation exposure associated with CT. The early adoption of hybrid PET/MRI, however, has been limited. To provide a viable alternative to the hybrid PET/MRI hardware by validating a software-based solution for PET-MR image coregistration. A fully automated, graphics processing unit-accelerated 3-D deformable image registration technique was used to align PET (acquired as PET/CT) and MR image pairs of 17 patients (age range: 10 months-21 years, mean: 10 years) who underwent PET/CT and body MRI (chest, abdomen or pelvis), which were performed within a 28-day (mean: 10.5 days) interval. MRI data for most of these cases included single-station post-contrast axial T1-weighted images. Following registration, maximum standardized uptake value (SUV{sub max}) values observed in coregistered PET (cPET) and the original PET were compared for 82 volumes of interest. In addition, we calculated the target registration error as a measure of the quality of image coregistration, and evaluated the algorithm's performance in the context of interexpert variability. The coregistration execution time averaged 97±45 s. The overall relative SUV{sub max} difference was 7% between cPET-MRI and PET/CT. The average target registration error was 10.7±6.6 mm, which compared favorably with the typical voxel size (diagonal distance) of 8.0 mm (typical resolution: 0.66 mm x 0.66 mm x 8 mm) for MRI and 6.1 mm (typical resolution: 3.65 mm x 3.65 mm x 3.27 mm) for PET. The variability in landmark identification did not show statistically significant differences between the algorithm and a typical expert. We have presented a software

  17. Fetal lung volume measurement by MRI with high-speed imaging systems

    Energy Technology Data Exchange (ETDEWEB)

    Osada, Hisao; Kaku, Kenshi [Chiba Univ. (Japan). Hospital

    2002-08-01

    Although ultrasonography is widely used for fetal morphologic observation, magnetic resonance imaging (MRI) has gained popularity as a new prenatal diagnostic method with recent introduction of high-speed imaging systems. Infants with lung hypoplasia affecting respiratory function require intensive management starting immediately after birth. Therefore, accurate prenatal differential diagnosis and severity evaluation are extremely important for these fetuses. The aim of this study is to measure fetal lung volume using a computer-based, three-dimensional MRI imaging system and to evaluate the possibility of clinical applications of this procedure. A total of 96 fetuses were evaluated, all were morphologically abnormal, and MRI was done for advanced assessment from 24 to 39 weeks gestation. Three-directional views of fetal chest were imaged by Signa Horizon, 1.5 Tesla, version 5.6 (General Electronics) with the following conditions; coil: TORSO coil, sequence: SSFSE (single shot fast spin echo), slice thickness: 5 mm, and imaging speed: 2 seconds/slice. To calculate the lung volume and create three-dimensional image, the lung area in each slice was traced out, then multiplied using computer image processing. Simultaneously, the volumes of all slices were summed to give the volume of each lung. Linear regression analysis and analysis of covariance (ANCOVA) were used for statistical analyses. In all cases, clear images were obtained, and were adequate for three-dimensional evaluation of the fetal lung. Thirty-five fetuses had poor outcomes, such as intrauterine fetal death, neonatal death, and intensive respiratory care. Regression lines of lung volume versus gestational week were calculated for these fetuses with poor outcome and 61 other fetuses with good outcome. ANCOVA, with gestational week as a covariant, revealed a significant intergroup difference in the lung volume (p<0.001). Similarly, regression lines of lung volume versus fetal body weight estimated by

  18. Architectures for single-chip image computing

    Science.gov (United States)

    Gove, Robert J.

    1992-04-01

    This paper will focus on the architectures of VLSI programmable processing components for image computing applications. TI, the maker of industry-leading RISC, DSP, and graphics components, has developed an architecture for a new-generation of image processors capable of implementing a plurality of image, graphics, video, and audio computing functions. We will show that the use of a single-chip heterogeneous MIMD parallel architecture best suits this class of processors--those which will dominate the desktop multimedia, document imaging, computer graphics, and visualization systems of this decade.

  19. Cardiac Imaging Using Clinical 1.5 T MRI Scanners in a Murine Ischemia/Reperfusion Model

    Directory of Open Access Journals (Sweden)

    Jakob G. J. Voelkl

    2011-01-01

    Full Text Available To perform cardiac imaging in mice without having to invest in expensive dedicated equipment, we adapted a clinical 1.5 Tesla (T magnetic resonance imaging (MRI scanner for use in a murine ischemia/reperfusion model. Phase-sensitive inversion recovery (PSIR sequence facilitated the determination of infarct sizes in vivo by late gadolinium enhancement. Results were compared to histological infarct areas in mice after ischemia/reperfusion procedure with a good correlation (=0.807, <.001. In addition, fractional area change (FAC was assessed with single slice cine MRI and was matched to infarct size (=−0.837 and fractional shortening (FS measured with echocardiography (=0.860; both <.001. Here, we demonstrate the use of clinical 1.5 MRI scanners as a feasible method for basic phenotyping in mice. These widely available scanners are capable of investigating in vivo infarct dimensions as well as assessment of cardiac functional parameters in mice with reasonable throughput.

  20. MRI quality control: six imagers studied using eleven unified image quality parameters

    International Nuclear Information System (INIS)

    Ihalainen, T.; Sipilae, O.; Savolainen, S.

    2004-01-01

    Quality control of the magnetic resonance imagers of different vendors in the clinical environment is non-harmonised, and comparing the performance is difficult. The purpose of this study was to develop and apply a harmonised long-term quality control protocol for the six imagers in our organisation in order to assure that they fulfil the same basic image quality requirements. The same Eurospin phantom set and identical imaging parameters were used with each imager. Values of 11 comparable parameters describing the image quality were measured. Automatic image analysis software was developed to objectively analyse the images. The results proved that the imagers were operating at a performance level adequate for clinical imaging. Some deficiencies were detected in image uniformity and geometry. The automated analysis of the Eurospin phantom images was successful. The measurements were successfully repeated after 2 weeks on one imager and after half a year on all imagers. As an objective way of examining the image quality, this kind of comparable and objective quality control of different imagers is considered as an essential step towards harmonisation of the clinical MRI studies through a large hospital organisation. (orig.)

  1. Photoacoustic imaging of breast tumor vascularization: a comparison with MRI and histopathology

    Science.gov (United States)

    Heijblom, Michelle; Piras, Daniele; van den Engh, Frank M.; Klaase, Joost M.; Brinkhuis, Mariël.; Steenbergen, Wiendelt; Manohar, Srirang

    2013-06-01

    Breast cancer is the most common form of cancer and the leading cause of cancer death among females. Early diagnosis improves the survival chances for the disease and that is why there is an ongoing search for improved methods for visualizing breast cancer. One of the hallmarks of breast cancer is the increase in tumor vascularization that is associated with angiogenesis: a crucial factor for survival of malignancies. Photoacoustic imaging can visualize the malignancyassociated increased hemoglobin concentration with optical contrast and ultrasound resolution, without the use of ionizing radiation or contrast agents and is therefore theoretically an ideal method for breast imaging. Previous clinical studies using the Twente Photoacoustic Mammoscope (PAM), which works in forward mode using a single wavelength (1064 nm), showed that malignancies can indeed be identified in the photoacoustic imaging volume as high contrast areas. However, the specific appearance of the malignancies led to questions about the contrast mechanism in relation to tumor vascularization. In this study, the photoacoustic lesion appearance obtained with an updated version of PAM is compared with the lesion appearance on Magnetic Resonance Imaging (MRI), both in general (19 patients) and on an individual basis (7 patients). Further, in 3 patients an extended histopathology protocol is being performed in which malignancies are stained for vascularity using an endothelial antibody: CD31. The correspondence between PAM and MRI and between PAM and histopathology makes it likely that the high photoacoustic contrast at 1064 nm is indeed largely the consequence of the increased tumor vascularization.

  2. Imaging brain microstructure with diffusion MRI: practicality and applications.

    Science.gov (United States)

    Alexander, Daniel C; Dyrby, Tim B; Nilsson, Markus; Zhang, Hui

    2017-11-29

    This article gives an overview of microstructure imaging of the brain with diffusion MRI and reviews the state of the art. The microstructure-imaging paradigm aims to estimate and map microscopic properties of tissue using a model that links these properties to the voxel scale MR signal. Imaging techniques of this type are just starting to make the transition from the technical research domain to wide application in biomedical studies. We focus here on the practicalities of both implementing such techniques and using them in applications. Specifically, the article summarizes the relevant aspects of brain microanatomy and the range of diffusion-weighted MR measurements that provide sensitivity to them. It then reviews the evolution of mathematical and computational models that relate the diffusion MR signal to brain tissue microstructure, as well as the expanding areas of application. Next we focus on practicalities of designing a working microstructure imaging technique: model selection, experiment design, parameter estimation, validation, and the pipeline of development of this class of technique. The article concludes with some future perspectives on opportunities in this topic and expectations on how the field will evolve in the short-to-medium term. Copyright © 2017 John Wiley & Sons, Ltd.

  3. Brain activity modification produced by a single radioelectric asymmetric brain stimulation pulse: a new tool for neuropsychiatric treatments. Preliminary fMRI study

    Directory of Open Access Journals (Sweden)

    Castagna A

    2011-10-01

    Full Text Available Salvatore Rinaldi1,2, Vania Fontani1, Alessandro Castagna1 1Department of Neuro-Psycho-Physio Pathology, Rinaldi Fontani Institute, Florence, Italy; 2Medical School of Occupational Medicine, University of Florence, Florence, Italy Purpose: Radioelectric asymmetric brain stimulation technology with its treatment protocols has shown efficacy in various psychiatric disorders. The aim of this work was to highlight the mechanisms by which these positive effects are achieved. The current study was conducted to determine whether a single 500-millisecond radioelectric asymmetric conveyor (REAC brain stimulation pulse (BSP, applied to the ear, can effect a modification of brain activity that is detectable using functional magnetic resonance imaging (fMRI. Methods: Ten healthy volunteers, six females and four males, underwent fMRI during a simple finger-tapping motor task before and after receiving a single 500-millisecond REAC-BSP. Results: The fMRI results indicate that the average variation in task-induced encephalic activation patterns is lower in subjects following the single REAC pulse. Conclusion: The current report demonstrates that a single REAC-BSP is sufficient to modulate brain activity in awake subjects, able to be measured using fMRI. These initial results open new perspectives into the understanding of the effects of weak and brief radio pulses upon brain activity, and provide the basis for further indepth studies using REAC-BSP and fMRI. Keywords: fMRI, brain stimulation, brain modulation, REAC, neuropsychiatric treatments

  4. Assessment of MRI Parameters as Imaging Biomarkers for Radiation Necrosis in the Rat Brain

    Energy Technology Data Exchange (ETDEWEB)

    Wang Silun [Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Tryggestad, Erik [Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Zhou Tingting [Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Armour, Michael [Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Wen Zhibo [Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong (China); Fu Dexue [Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Ford, Eric [Department of Radiation Oncology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Zijl, Peter C.M. van [Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland (United States); Zhou Jinyuan, E-mail: jzhou@mri.jhu.edu [Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland (United States)

    2012-07-01

    Purpose: Radiation necrosis is a major complication of radiation therapy. We explore the features of radiation-induced brain necrosis in the rat, using multiple MRI approaches, including T{sub 1}, T{sub 2}, apparent diffusion constant (ADC), cerebral blood flow (CBF), magnetization transfer ratio (MTR), and amide proton transfer (APT) of endogenous mobile proteins and peptides. Methods and Materials: Adult rats (Fischer 344; n = 15) were irradiated with a single, well-collimated X-ray beam (40 Gy; 10 Multiplication-Sign 10 mm{sup 2}) in the left brain hemisphere. MRI was acquired on a 4.7-T animal scanner at {approx}25 weeks' postradiation. The MRI signals of necrotic cores and perinecrotic regions were assessed with a one-way analysis of variance. Histological evaluation was accomplished with hematoxylin and eosin staining. Results: ADC and CBF MRI could separate perinecrotic and contralateral normal brain tissue (p < 0.01 and < 0.05, respectively), whereas T{sub 1}, T{sub 2}, MTR, and APT could not. MRI signal intensities were significantly lower in the necrotic core than in normal brain for CBF (p < 0.001) and APT (p < 0.01) and insignificantly higher or lower for T{sub 1}, T{sub 2}, MTR, and ADC. Histological results demonstrated coagulative necrosis within the necrotic core and reactive astrogliosis and vascular damage within the perinecrotic region. Conclusion: ADC and CBF are promising imaging biomarkers for identifying perinecrotic regions, whereas CBF and APT are promising for identifying necrotic cores.

  5. Use of personal computer image for processing a magnetic resonance image (MRI)

    International Nuclear Information System (INIS)

    Yamamoto, Tetsuo; Tanaka, Hitoshi

    1988-01-01

    Image processing of MR imaging was attempted by using a popular personal computer as 16-bit model. The computer processed the images on a 256 x 256 matrix and 512 x 512 matrix. The softwer languages for image-processing were those of Macro-Assembler performed by (MS-DOS). The original images, acuired with an 0.5 T superconducting machine (VISTA MR 0.5 T, Picker International) were transfered to the computer by the flexible disket. Image process are the display of image to monitor, other the contrast enhancement, the unsharped mask contrast enhancement, the various filter process, the edge detections or the color histogram was obtained in 1.6 sec to 67 sec, indicating that commercialzed personal computer had ability for routine clinical purpose in MRI-processing. (author)

  6. Testing the quality of images for permanent magnet desktop MRI systems using specially designed phantoms.

    Science.gov (United States)

    Qiu, Jianfeng; Wang, Guozhu; Min, Jiao; Wang, Xiaoyan; Wang, Pengcheng

    2013-12-21

    Our aim was to measure the performance of desktop magnetic resonance imaging (MRI) systems using specially designed phantoms, by testing imaging parameters and analysing the imaging quality. We designed multifunction phantoms with diameters of 18 and 60 mm for desktop MRI scanners in accordance with the American Association of Physicists in Medicine (AAPM) report no. 28. We scanned the phantoms with three permanent magnet 0.5 T desktop MRI systems, measured the MRI image parameters, and analysed imaging quality by comparing the data with the AAPM criteria and Chinese national standards. Image parameters included: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, signal-to-noise ratio (SNR), and image uniformity. The image parameters of three desktop MRI machines could be measured using our specially designed phantoms, and most parameters were in line with MRI quality control criterion, including: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, image uniformity and slice position accuracy. However, SNR was significantly lower than in some references. The imaging test and quality control are necessary for desktop MRI systems, and should be performed with the applicable phantom and corresponding standards.

  7. Testing the quality of images for permanent magnet desktop MRI systems using specially designed phantoms

    International Nuclear Information System (INIS)

    Qiu, Jianfeng; Wang, Guozhu; Min, Jiao; Wang, Xiaoyan; Wang, Pengcheng

    2013-01-01

    Our aim was to measure the performance of desktop magnetic resonance imaging (MRI) systems using specially designed phantoms, by testing imaging parameters and analysing the imaging quality. We designed multifunction phantoms with diameters of 18 and 60 mm for desktop MRI scanners in accordance with the American Association of Physicists in Medicine (AAPM) report no. 28. We scanned the phantoms with three permanent magnet 0.5 T desktop MRI systems, measured the MRI image parameters, and analysed imaging quality by comparing the data with the AAPM criteria and Chinese national standards. Image parameters included: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, signal-to-noise ratio (SNR), and image uniformity. The image parameters of three desktop MRI machines could be measured using our specially designed phantoms, and most parameters were in line with MRI quality control criterion, including: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, image uniformity and slice position accuracy. However, SNR was significantly lower than in some references. The imaging test and quality control are necessary for desktop MRI systems, and should be performed with the applicable phantom and corresponding standards. (paper)

  8. Image to physical space registration of supine breast MRI for image guided breast surgery

    Science.gov (United States)

    Conley, Rebekah H.; Meszoely, Ingrid M.; Pheiffer, Thomas S.; Weis, Jared A.; Yankeelov, Thomas E.; Miga, Michael I.

    2014-03-01

    Breast conservation therapy (BCT) is a desirable option for many women diagnosed with early stage breast cancer and involves a lumpectomy followed by radiotherapy. However, approximately 50% of eligible women will elect for mastectomy over BCT despite equal survival benefit (provided margins of excised tissue are cancer free) due to uncertainty in outcome with regards to complete excision of cancerous cells, risk of local recurrence, and cosmesis. Determining surgical margins intraoperatively is difficult and achieving negative margins is not as robust as it needs to be, resulting in high re-operation rates and often mastectomy. Magnetic resonance images (MRI) can provide detailed information about tumor margin extents, however diagnostic images are acquired in a fundamentally different patient presentation than that used in surgery. Therefore, the high quality diagnostic MRIs taken in the prone position with pendant breast are not optimal for use in surgical planning/guidance due to the drastic shape change between preoperative images and the common supine surgical position. This work proposes to investigate the value of supine MRI in an effort to localize tumors intraoperatively using image-guidance. Mock intraoperative setups (realistic patient positioning in non-sterile environment) and preoperative imaging data were collected from a patient scheduled for a lumpectomy. The mock intraoperative data included a tracked laser range scan of the patient's breast surface, tracked center points of MR visible fiducials on the patient's breast, and tracked B-mode ultrasound and strain images. The preoperative data included a supine MRI with visible fiducial markers. Fiducial markers localized in the MRI were rigidly registered to their mock intraoperative counterparts using an optically tracked stylus. The root mean square (RMS) fiducial registration error using the tracked markers was 3.4mm. Following registration, the average closest point distance between the MR

  9. Multishot versus single-shot pulse sequences in very high field fMRI: a comparison using retinotopic mapping.

    Directory of Open Access Journals (Sweden)

    Jascha D Swisher

    Full Text Available High-resolution functional MRI is a leading application for very high field (7 Tesla human MR imaging. Though higher field strengths promise improvements in signal-to-noise ratios (SNR and BOLD contrast relative to fMRI at 3 Tesla, these benefits may be partially offset by accompanying increases in geometric distortion and other off-resonance effects. Such effects may be especially pronounced with the single-shot EPI pulse sequences typically used for fMRI at standard field strengths. As an alternative, one might consider multishot pulse sequences, which may lead to somewhat lower temporal SNR than standard EPI, but which are also often substantially less susceptible to off-resonance effects. Here we consider retinotopic mapping of human visual cortex as a practical test case by which to compare examples of these sequence types for high-resolution fMRI at 7 Tesla. We performed polar angle retinotopic mapping at each of 3 isotropic resolutions (2.0, 1.7, and 1.1 mm using both accelerated single-shot 2D EPI and accelerated multishot 3D gradient-echo pulse sequences. We found that single-shot EPI indeed led to greater temporal SNR and contrast-to-noise ratios (CNR than the multishot sequences. However, additional distortion correction in postprocessing was required in order to fully realize these advantages, particularly at higher resolutions. The retinotopic maps produced by both sequence types were qualitatively comparable, and showed equivalent test/retest reliability. Thus, when surface-based analyses are planned, or in other circumstances where geometric distortion is of particular concern, multishot pulse sequences could provide a viable alternative to single-shot EPI.

  10. Technique of obstetric pelvimetry by magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Sigmund, G.; Wenz, W.; Bauer, M.; DeGregorio, G.; Henne, K.

    1991-01-01

    Magnetic resonance imaging (MRL) allows for the first time direct determination of maternal pelvic dimensions without ionising radiation. Phantom measurements and the correlation with traditional pelvimetric measurements in 10 patients after Caesarean section have shown mean differences of ± 2 mm, with a maximum of 5 mm. The evaluation of pelvic configuration is obtained analogous to the conventional roentgenogram. In addition to conventional or digital X-ray pelvimetry, the soft tissues of the maternal pelvis and the presenting part of the foetus is delineated with high contrast. Positioning in the body coil can be accomplished even late in pregnancy or in impending labour, acceptance by the pregnant women being high. Whereas in a given indication after delivery conventional X-ray pelvimetry continues to be performed, antenatally MRI pelvimetry has now been established in our Departments as the method of choice - based on meanwhile 107 examinations. Present drawbacks are the relatively high cost and the limited availability of MR units. (orig.) [de

  11. Electric field imaging of single atoms

    Science.gov (United States)

    Shibata, Naoya; Seki, Takehito; Sánchez-Santolino, Gabriel; Findlay, Scott D.; Kohno, Yuji; Matsumoto, Takao; Ishikawa, Ryo; Ikuhara, Yuichi

    2017-01-01

    In scanning transmission electron microscopy (STEM), single atoms can be imaged by detecting electrons scattered through high angles using post-specimen, annular-type detectors. Recently, it has been shown that the atomic-scale electric field of both the positive atomic nuclei and the surrounding negative electrons within crystalline materials can be probed by atomic-resolution differential phase contrast STEM. Here we demonstrate the real-space imaging of the (projected) atomic electric field distribution inside single Au atoms, using sub-Å spatial resolution STEM combined with a high-speed segmented detector. We directly visualize that the electric field distribution (blurred by the sub-Å size electron probe) drastically changes within the single Au atom in a shape that relates to the spatial variation of total charge density within the atom. Atomic-resolution electric field mapping with single-atom sensitivity enables us to examine their detailed internal and boundary structures. PMID:28555629

  12. Assessing MRI susceptibility artefact through an indicator of image distortion

    Directory of Open Access Journals (Sweden)

    Illanes Alfredo

    2016-09-01

    Full Text Available Susceptibility artefacts in magnetic resonance imaging (MRI caused by medical devices can result in a severe degradation of the MR image quality. The quantification of susceptibility artefacts is regulated by the ASTM standard which defines a manual method to assess the size of an artefact. This means that the estimated artefact size can be user dependent. To cope with this problem, we propose an algorithm to automatically quantify the size of such susceptibility artefacts. The algorithm is based on the analysis of a 3D surface generated from the 2D MR images. The results obtained by the automatic algorithm were compared to the manual measurements performed by study participants. The results show that the automatic and manual measurements follow the same trend. The clear advantage of the automated algorithm is the absence of the inter- and intra-observer variability. In addition, the algorithm also detects the slice containing the largest artefact which was not the case for the manual measurements.

  13. Magnetosomes used as biogenic MRI contrast agent for molecular imaging of glioblastoma model

    International Nuclear Information System (INIS)

    Boucher, Marianne

    2016-01-01

    This work takes place in the context of molecular imaging, which aims at tailoring medical treatments and therapies to the individual context by revealing molecular or cellular phenomenon of medical interest in the less invasive manner. In particular, it can be achieved with MRI molecular imaging using engineered iron-oxide contrast agent.This PhD thesis focuses on the study of a new class of iron-oxide contrast agent for high field MRI. Indeed, magnetosomes are natural iron-oxide vesicles produced by magneto-tactic bacteria. These bacteria synthesized such magnetic vesicles and ordered them like a nano-compass in order to facilitate their navigation in sediments. This explains why magnetosomes are awarded with tremendous magnetic properties: around 50 nm, mono-crystalline, single magnetic domain and high saturation magnetization. Furthermore, a wide variety of bacterial strains exist in nature and size and shape of magnetosomes are highly stable within strain and can be very different between strains. Finally, magnetosomes are naturally coated with a bi-lipidic membrane whose content is genetically determined. Lately, researchers have unravelled magnetosomes membrane protein contents, opening the way to create functionalized magnetosomes thanks to fusion of the gene coding for a protein of interest with the gene coding for an abundant protein at magnetosomes membrane.A new alternative path using living organisms to tackle the production of engineered high efficiency molecular imaging probes have been investigated with magneto-tactic bacteria in this PhD. The production and engineering of magnetosomes have been carried out by our partner, the Laboratoire de Bio-energetique Cellulaire (LBC, CEA Cadarache), and will be presented and discussed. We then characterized magnetosomes as contrast agent for high field MRI. We showed they present very promising contrasting properties in vitro, and assessed this observation in vivo by establishing they can be used as efficient

  14. SU-F-I-16: Short Breast MRI with High-Resolution T2-Weighted and Dynamic Contrast Enhanced T1-Weighted Images

    International Nuclear Information System (INIS)

    Ma, J; Son, J; Arun, B; Hazle, J; Hwang, K; Madewell, J; Yang, W; Dogan, B; Wang, K; Bayram, E

    2016-01-01

    Purpose: To develop and demonstrate a short breast (sb) MRI protocol that acquires both T2-weighted and dynamic contrast-enhanced T1-weighted images in approximately ten minutes. Methods: The sb-MRI protocol consists of two novel pulse sequences. The first is a flexible fast spin-echo triple-echo Dixon (FTED) sequence for high-resolution fat-suppressed T2-weighted imaging, and the second is a 3D fast dual-echo spoiled gradient sequence (FLEX) for volumetric fat-suppressed T1-weighted imaging before and post contrast agent injection. The flexible FTED sequence replaces each single readout during every echo-spacing period of FSE with three fast-switching bipolar readouts to produce three raw images in a single acquisition. These three raw images are then post-processed using a Dixon algorithm to generate separate water-only and fat-only images. The FLEX sequence acquires two echoes using dual-echo readout after each RF excitation and the corresponding images are post-processed using a similar Dixon algorithm to yield water-only and fat-only images. The sb-MRI protocol was implemented on a 3T MRI scanner and used for patients who had undergone concurrent clinical MRI for breast cancer screening. Results: With the same scan parameters (eg, spatial coverage, field of view, spatial and temporal resolution) as the clinical protocol, the total scan-time of the sb-MRI protocol (including the localizer, bilateral T2-weighted, and dynamic contrast-enhanced T1-weighted images) was 11 minutes. In comparison, the clinical breast MRI protocol took 43 minutes. Uniform fat suppression and high image quality were consistently achieved by sb-MRI. Conclusion: We demonstrated a sb-MRI protocol comprising both T2-weighted and dynamic contrast-enhanced T1-weighted images can be performed in approximately ten minutes. The spatial and temporal resolution of the images easily satisfies the current breast MRI accreditation guidelines by the American College of Radiology. The protocol has the

  15. SU-F-I-16: Short Breast MRI with High-Resolution T2-Weighted and Dynamic Contrast Enhanced T1-Weighted Images

    Energy Technology Data Exchange (ETDEWEB)

    Ma, J; Son, J; Arun, B; Hazle, J; Hwang, K; Madewell, J; Yang, W; Dogan, B [UT MD Anderson Cancer Center, Houston, TX (United States); Wang, K; Bayram, E [GE Healthcare Technologies, Waukesha, Wisconsin (United States)

    2016-06-15

    Purpose: To develop and demonstrate a short breast (sb) MRI protocol that acquires both T2-weighted and dynamic contrast-enhanced T1-weighted images in approximately ten minutes. Methods: The sb-MRI protocol consists of two novel pulse sequences. The first is a flexible fast spin-echo triple-echo Dixon (FTED) sequence for high-resolution fat-suppressed T2-weighted imaging, and the second is a 3D fast dual-echo spoiled gradient sequence (FLEX) for volumetric fat-suppressed T1-weighted imaging before and post contrast agent injection. The flexible FTED sequence replaces each single readout during every echo-spacing period of FSE with three fast-switching bipolar readouts to produce three raw images in a single acquisition. These three raw images are then post-processed using a Dixon algorithm to generate separate water-only and fat-only images. The FLEX sequence acquires two echoes using dual-echo readout after each RF excitation and the corresponding images are post-processed using a similar Dixon algorithm to yield water-only and fat-only images. The sb-MRI protocol was implemented on a 3T MRI scanner and used for patients who had undergone concurrent clinical MRI for breast cancer screening. Results: With the same scan parameters (eg, spatial coverage, field of view, spatial and temporal resolution) as the clinical protocol, the total scan-time of the sb-MRI protocol (including the localizer, bilateral T2-weighted, and dynamic contrast-enhanced T1-weighted images) was 11 minutes. In comparison, the clinical breast MRI protocol took 43 minutes. Uniform fat suppression and high image quality were consistently achieved by sb-MRI. Conclusion: We demonstrated a sb-MRI protocol comprising both T2-weighted and dynamic contrast-enhanced T1-weighted images can be performed in approximately ten minutes. The spatial and temporal resolution of the images easily satisfies the current breast MRI accreditation guidelines by the American College of Radiology. The protocol has the

  16. Dual isotope, single acquisition parathyroid imaging

    International Nuclear Information System (INIS)

    Triantafillou, M.; McDonald, H.J.

    1998-01-01

    Full text: Nuclear Medicine parathyroid imaging using Thallium-201(TI) and Technetium-99m(Tc) is an often used imaging modality for the detection of parathyroid adenomas and hyper parathyroidism. The conventional Tl/Tc subtraction technique requires 2 separate injections and acquisitions which are then normalised and subtracted from each other. This lengthy technique is uncomfortable for patients and can result in false positive scan results due to patient movement between and during the acquisition process. We propose a simplified injection and single acquisition technique, that reduces the chance of movement and thus reduces the chance of false positive scan results. The technique involves the injection of Tc followed by the Tl injection 10 minutes later. After a further 10 min wait, imaging is performed using a dual isotope acquisition, with window (W) 1 set on 140 keV 20%W 5% off peak and W2 peaked for 70 keV 20%W., acquired for 10 minutes. We have imaged 27 patients with this technique, 15 had positive parathyroid imaging. Of the 15, 11 had positive ultrasound correlation. Of the remaining 4, 2 have had positive surgical findings for adenomas, the other 2 are awaiting follow-up. Of the 12 patients with negative parathyroid imaging, 2 have been shown to be false - negative with surgery. In conclusion, the single acquisition technique suggested by us is a valid method of imaging parathyroids that reduces the chance of false positive results due to movement

  17. Feasibility study on 3D image reconstruction from 2D orthogonal cine-MRI for MRI-guided radiotherapy.

    Science.gov (United States)

    Paganelli, Chiara; Lee, Danny; Kipritidis, John; Whelan, Brendan; Greer, Peter B; Baroni, Guido; Riboldi, Marco; Keall, Paul

    2018-02-11

    In-room MRI is a promising image guidance strategy in external beam radiotherapy to acquire volumetric information for moving targets. However, limitations in spatio-temporal resolution led several authors to use 2D orthogonal images for guidance. The aim of this work is to present a method to concurrently compensate for non-rigid tumour motion and provide an approach for 3D reconstruction from 2D orthogonal cine-MRI slices for MRI-guided treatments. Free-breathing sagittal/coronal interleaved 2D cine-MRI were acquired in addition to a pre-treatment 3D volume in two patients. We performed deformable image registration (DIR) between cine-MRI slices and corresponding slices in the pre-treatment 3D volume. Based on an extrapolation of the interleaved 2D motion fields, the 3D motion field was estimated and used to warp the pre-treatment volume. Due to the lack of a ground truth for patients, the method was validated on a digital 4D lung phantom. On the phantom, the 3D reconstruction method was able to compensate for tumour motion and compared favourably to the results of previously adopted strategies. The difference in the 3D motion fields between the phantom and the extrapolated motion was 0.4 ± 0.3 mm for tumour and 0.8 ± 1.5 mm for whole anatomy, demonstrating feasibility of performing a 3D volumetric reconstruction directly from 2D orthogonal cine-MRI slices. Application of the method to patient data confirmed the feasibility of utilizing this method in real world scenarios. Preliminary results on phantom and patient cases confirm the feasibility of the proposed approach in an MRI-guided scenario, especially for non-rigid tumour motion compensation. © 2018 The Royal Australian and New Zealand College of Radiologists.

  18. Decoded fMRI neurofeedback can induce bidirectional confidence changes within single participants.

    Science.gov (United States)

    Cortese, Aurelio; Amano, Kaoru; Koizumi, Ai; Lau, Hakwan; Kawato, Mitsuo

    2017-04-01

    Neurofeedback studies using real-time functional magnetic resonance imaging (rt-fMRI) have recently incorporated the multi-voxel pattern decoding approach, allowing for fMRI to serve as a tool to manipulate fine-grained neural activity embedded in voxel patterns. Because of its tremendous potential for clinical applications, certain questions regarding decoded neurofeedback (DecNef) must be addressed. Specifically, can the same participants learn to induce neural patterns in opposite directions in different sessions? If so, how does previous learning affect subsequent induction effectiveness? These questions are critical because neurofeedback effects can last for months, but the short- to mid-term dynamics of such effects are unknown. Here we employed a within-subjects design, where participants underwent two DecNef training sessions to induce behavioural changes of opposing directionality (up or down regulation of perceptual confidence in a visual discrimination task), with the order of training counterbalanced across participants. Behavioral results indicated that the manipulation was strongly influenced by the order and the directionality of neurofeedback training. We applied nonlinear mathematical modeling to parametrize four main consequences of DecNef: main effect of change in confidence, strength of down-regulation of confidence relative to up-regulation, maintenance of learning effects, and anterograde learning interference. Modeling results revealed that DecNef successfully induced bidirectional confidence changes in different sessions within single participants. Furthermore, the effect of up- compared to down-regulation was more prominent, and confidence changes (regardless of the direction) were largely preserved even after a week-long interval. Lastly, the effect of the second session was markedly diminished as compared to the effect of the first session, indicating strong anterograde learning interference. These results are interpreted in the framework

  19. MRI imaging of displaced meniscal tears: Report of a case highlighting new potential pitfalls of the MRI signs

    International Nuclear Information System (INIS)

    Prasad, Abhishek; Brar, Rahat; Rana, Shaleen

    2014-01-01

    Magnetic resonance imaging (MRI) has been found to be an excellent imaging tool for meniscal injuries. Various MRI signs have been described to detect displaced meniscal injuries, specifically the bucket-handle tears. Although these signs are quite helpful in diagnosing meniscal tears, various pitfalls have also been reported for these signs. Double anterior cruciate ligament (ACL) sign refers to presence of a linear hypointense soft tissue anterior to the ACL, which represented the flipped bucket-handle tear of the meniscus. Disproportional posterior horn and flipped meniscus signs represent asymmetrically thickened horns of the menisci due to overlying displaced meniscal fragments. We report a case wherein MRI of the knee showed tear and displacement of the medial patellofemoral ligament (MPFL) and vastus medialis complex, medial collateral ligament (MCL), and posterior cruciate ligament (PCL) mimicking these signs. To our knowledge, internally displaced MPFL and MCLs have not been described as mimics for displaced meniscal fragments

  20. Vision 20/20: Simultaneous CT-MRI — Next chapter of multimodality imaging

    International Nuclear Information System (INIS)

    Wang, Ge; Xi, Yan; Gjesteby, Lars; Getzin, Matthew; Yang, Qingsong; Cong, Wenxiang; Kalra, Mannudeep; Murugan, Venkatesh; Vannier, Michael

    2015-01-01

    Multimodality imaging systems such as positron emission tomography-computed tomography (PET-CT) and MRI-PET are widely available, but a simultaneous CT-MRI instrument has not been developed. Synergies between independent modalities, e.g., CT, MRI, and PET/SPECT can be realized with image registration, but such postprocessing suffers from registration errors that can be avoided with synchronized data acquisition. The clinical potential of simultaneous CT-MRI is significant, especially in cardiovascular and oncologic applications where studies of the vulnerable plaque, response to cancer therapy, and kinetic and dynamic mechanisms of targeted agents are limited by current imaging technologies. The rationale, feasibility, and realization of simultaneous CT-MRI are described in this perspective paper. The enabling technologies include interior tomography, unique gantry designs, open magnet and RF sequences, and source and detector adaptation. Based on the experience with PET-CT, PET-MRI, and MRI-LINAC instrumentation where hardware innovation and performance optimization were instrumental to construct commercial systems, the authors provide top-level concepts for simultaneous CT-MRI to meet clinical requirements and new challenges. Simultaneous CT-MRI fills a major gap of modality coupling and represents a key step toward the so-called “omnitomography” defined as the integration of all relevant imaging modalities for systems biology and precision medicine

  1. Vision 20/20: Simultaneous CT-MRI — Next chapter of multimodality imaging

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ge, E-mail: wangg6@rpi.edu; Xi, Yan; Gjesteby, Lars; Getzin, Matthew; Yang, Qingsong; Cong, Wenxiang [Biomedical Imaging Center/Cluster, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Kalra, Mannudeep; Murugan, Venkatesh [Department of Imaging, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114 (United States); Vannier, Michael [Department of Radiology, University of Chicago, Chicago, Illinois 60637 (United States)

    2015-10-15

    Multimodality imaging systems such as positron emission tomography-computed tomography (PET-CT) and MRI-PET are widely available, but a simultaneous CT-MRI instrument has not been developed. Synergies between independent modalities, e.g., CT, MRI, and PET/SPECT can be realized with image registration, but such postprocessing suffers from registration errors that can be avoided with synchronized data acquisition. The clinical potential of simultaneous CT-MRI is significant, especially in cardiovascular and oncologic applications where studies of the vulnerable plaque, response to cancer therapy, and kinetic and dynamic mechanisms of targeted agents are limited by current imaging technologies. The rationale, feasibility, and realization of simultaneous CT-MRI are described in this perspective paper. The enabling technologies include interior tomography, unique gantry designs, open magnet and RF sequences, and source and detector adaptation. Based on the experience with PET-CT, PET-MRI, and MRI-LINAC instrumentation where hardware innovation and performance optimization were instrumental to construct commercial systems, the authors provide top-level concepts for simultaneous CT-MRI to meet clinical requirements and new challenges. Simultaneous CT-MRI fills a major gap of modality coupling and represents a key step toward the so-called “omnitomography” defined as the integration of all relevant imaging modalities for systems biology and precision medicine.

  2. DW-MRI of liver lesions: Can a single ADC-value represent the entire lesion?

    International Nuclear Information System (INIS)

    Schmid-Tannwald, C.; Dahi, F.; Jiang, Y.; Ivancevic, M.K.; Rist, C.; Sethi, I.; Oommen, J.; Oto, A.

    2014-01-01

    Aim: To evaluate whether focal liver lesions (FLLs) exhibit a homogeneous appearance on apparent diffusion coefficient (ADC) maps and whether there is inter-section variation in the calculated ADC values of FLLs (inter-section range). Materials and methods: Eighty-eight patients with 128 FLLs (70 benign, 58 malignant) who underwent abdominal magnetic resonance imaging (MRI) including diffusion-weighted (DW)-MRI were included. Two observers evaluated variation of signal intensity of each FLL within each ADC map image (intra-section) and among different ADC map images through the lesion (inter-section). ADC values of each FLL and neighbouring liver parenchyma were measured on all sections. The inter-section range of FLLs was compared with the neighbouring liver parenchyma. Results: Intra-section inhomogeneity was noted in 39.8% (97/244 sections) and 38.9% (95/244) of benign lesions, and 61% (114/187 sections) and 61.5% (115/187) of malignant lesions, by observer 1 and observer 2, respectively. Inter-section inhomogeneity was noted in 25.7% (18/70) and 27.1% (19/70) of benign lesions, and 51.7% (30/58) and 50% (29/58) of malignant lesions, by observer 1 and observer 2, respectively. The inter-section range for both benign (0.28 × 10 −3  mm²/s) and malignant (0.25 × 10 −3  mm²/s) FLLs were significantly greater than that of liver parenchyma surrounding benign (0.16 × 10 −3  mm²/s, p < 0.001) and malignant (0.14 × 10 −3  mm²/s, p = 0.01) FLLs. Conclusion: Due to intra-/inter-section variations in ADC values of benign and malignant FLLs, a single ADC value may not reliably represent the entire lesion

  3. Magnetic resonance imaging (MRI) of the cardiovascular system

    International Nuclear Information System (INIS)

    Yoshida, Shigeru

    1991-01-01

    Qualitative assessments of the hypertrophied myocardium were performed using spin-lattice relaxation time (T1) and spin-spin relaxation time (T2) obtained by magnetic resonance imaging (MRI) in 15 normotensive patients with asymmetric septal hypertrophy (ASH), 10 hypertensive patients with concentric hypertrophy (CH) and 5 normal subjects (N). The changes of these values were evaluated related to cardiac cycle, and their usefulness in differentiating diseases. The wall thickness and internal dimension of the left ventricle (LV) in 10 cases were obtained using echocardiography and MRI, and there was a good correlation coefficient in wall thickness (r=0.987) and in internal dimension (r=0.991). Left ventricular short-axis images were obtained using ECG-gated spin-echo sequence (Te=30, 80 msec) and using inversion recovery sequence. T1 and T2 images were calculated at endsystolic and diastolic cardiac phases. The regional wall thickness (WT) and T1 and T2 values were measured in the anterior septum, anterior wall, lateral wall, posterior wall and posterior septum. Myocardial T1 and T2 values were significantly decreased in systole (T1: 185.6±37.9 msec, T2: 24.4±6.3 msec) compared to those in diastole (T1: 249.2±56.7 msec, T2: 31.7±9.4 msec). In both ASH and CH groups, significant correlations were observed between diastolic T1 values and WT (ASH: r=0.80, CH: r=0.45), and between diastolic T2 values and WT (ASH: r=0.58, CH: r=0.60). In the regions where diastolic WT were more than 17 mm, T1 values in the ASH group (343.4±40.5 msec) were significantly higher than those of the CH group (247.3±21.4 msec), although the mean wall thickness values were similar in both groups. These results indicate that myocardial relaxation times are related to cardiac cycle, wall thickness and types of hypertrophy. The T1 and T2 values at diastolic cardiac phase might be useful for distinguishing hypertrophic cardiomyopathy from hypertrophy due to hypertension. (author)

  4. Focal Pancreatitis Mimicking Pancreatic Mass: Magnetic Resonance Imaging (MRI)/Magnetic Resonance Cholangiopancreatography (MRCP) Findings Including Diffusion-Weighted MRI

    International Nuclear Information System (INIS)

    Momtahen, A.J.; Balci, N.C.; Alkaade, S.; Akduman, E.I.; Burton, F.R.

    2008-01-01

    Background: Focal pancreatitis (FP) is a confined inflammation that mimics a pancreatic mass. Its imaging diagnosis is important to avoid unnecessary procedures. Purpose: To describe the spectrum of magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP) and diffusion-weighted MRI (DWI) findings of focal pancreatitis mimicking pancreatic masses. Material and Methods: Findings of MRI/MRCP including DWI with a b value of 0 and 600 s/mm2 in 14 patients with pancreatic masses on MRI were retrospectively reviewed and compared to normal pancreas in 14 patients as a control group. Results: FP revealed hypointense signal intensity (SI) (3/14), hypo- to isointense SI (7/14), or isointense SI (4/14) on T1-weighted images, and hypointense SI (1/14), isointense SI (5/14), iso- to hyperintense SI (7/14), or hyperintense SI (1/14) on T2-weighted images compared to remaining pancreas (RP). MRCP images revealed dilatation of the common bile duct (CBD) and main pancreatic duct (MPD) (5/14), dilatation of the MPD only (3/14), dilatation of the CBD only (3/14), and normal MPD and CBD (3/14). Both FP and RP revealed three types of time-signal intensity curves: 1) rapid rise to a peak, with a rapid decline (FP=2, RP=4), 2) slow rise to a peak, followed by a slow decline (FP=5, RP=4), and 3) slower rise to a peak, with a slow decline or plateau (FP=7, RP=6). Mean apparent diffusion coefficient (ADC) values for FP and RP were 2.09±0.18 and 2.03±0.2x10 -3 mm 2 /s, respectively. ADC values of FP and RP revealed no significant difference. Conclusion: The spectrum of imaging findings of focal pancreatitis on MRI/MRCP including DWI was described. Findings of FP were not distinctive as compared to the remaining pancreas

  5. Study of human brain functions by functional magnetic resonance imaging (fMRI) and spectroscopy (fMRS)

    International Nuclear Information System (INIS)

    Jagannathan, N.R.

    1998-01-01

    Functional magnetic resonance imaging (fMRI) has become a powerful tool in the detection and assessment of cerebral pathophysiology and the regional mapping and characterization of cognitive processes such as motor skills, vision, language and memory. The results of the effect of motor cortex stimulation during repetitive hand squeezing task activation using in-vivo single voxel NMR spectroscopy carried out on normal volunteer subjects are presented

  6. Comparison of particle image velocimetry and phase contrast MRI in a patient-specific extracardiac total cavopulmonary connection.

    Science.gov (United States)

    Kitajima, Hiroumi D; Sundareswaran, Kartik S; Teisseyre, Thomas Z; Astary, Garrett W; Parks, W James; Skrinjar, Oskar; Oshinski, John N; Yoganathan, Ajit P

    2008-08-01

    Particle image velocimetry (PIV) and phase contrast magnetic resonance imaging (PC-MRI) have not been compared in complex biofluid environments. Such analysis is particularly useful to investigate flow structures in the correction of single ventricle congenital heart defects, where fluid dynamic efficiency is essential. A stereolithographic replica of an extracardiac total cavopulmonary connection (TCPC) is studied using PIV and PC-MRI in a steady flow loop. Volumetric two-component PIV is compared to volumetric three-component PC-MRI at various flow conditions. Similar flow structures are observed in both PIV and PC-MRI, where smooth flow dominates the extracardiac TCPC, and superior vena cava flow is preferential to the right pulmonary artery, while inferior vena cava flow is preferential to the left pulmonary artery. Where three-component velocity is available in PC-MRI studies, some helical flow in the extracardiac TCPC is observed. Vessel cross sections provide an effective means of validation for both experiments, and velocity magnitudes are of the same order. The results highlight similarities to validate flow in a complex patient-specific extracardiac TCPC. Additional information obtained by velocity in three components further describes the complexity of the flow in anatomic structures.

  7. Molecular imaging of head and neck cancers. Perspectives of PET/MRI

    International Nuclear Information System (INIS)

    Stumpp, P.; Kahn, T.; Purz, S.; Sabri, O.

    2016-01-01

    The 18 F-fluorodeoxyglucose positron emission tomography-computed tomography ( 18 F-FDG-PET/CT) procedure is a cornerstone in the diagnostics of head and neck cancers. Several years ago PET-magnetic resonance imaging (PET/MRI) also became available as an alternative hybrid multimodal imaging method. Does PET/MRI have advantages over PET/CT in the diagnostics of head and neck cancers ?The diagnostic accuracy of the standard imaging methods CT, MRI and PET/CT is depicted according to currently available meta-analyses and studies concerning the use of PET/MRI for these indications are summarized. In all studies published up to now PET/MRI did not show superiority regarding the diagnostic accuracy in head and neck cancers; however, there is some evidence that in the future PET/MRI can contribute to tumor characterization and possibly be used to predict tumor response to therapy with the use of multiparametric imaging. Currently, 18 F-FDG-PET/CT is not outperformed by PET/MRI in the diagnostics of head and neck cancers. The additive value of PET/MRI due to the use of multiparametric imaging needs to be investigated in future research. (orig.) [de

  8. SU-F-J-110: MRI-Guided Single-Session Simulation, Online Adaptation, and Treatment

    International Nuclear Information System (INIS)

    Hill, P; Geurts, M; Mittauer, K; Bayouth, J

    2016-01-01

    Purpose: To develop a combined simulation and treatment workflow for MRI-guided radiation therapy using the ViewRay treatment planning and delivery system. Methods: Several features of the ViewRay MRIdian planning and treatment workflows are used to simulate and treat patients that require emergent radiotherapy. A simple “pre-plan” is created on diagnostic imaging retrieved from radiology PACS, where conformal fields are created to target a volume defined by a physician based on review of the diagnostic images and chart notes. After initial consult in radiation oncology, the patient is brought to the treatment room, immobilized, and imaged in treatment position with a volumetric MR. While the patient rests on the table, the pre-plan is applied to the treatment planning MR and dose is calculated in the treatment geometry. After physician review, modification of the plan may include updating the target definition, redefining fields, or re-balancing beam weights. Once an acceptable treatment plan is finalized and approved, the patient is treated. Results: Careful preparation and judicious choices in the online planning process allow conformal treatment plans to be created and delivered in a single, thirty-minute session. Several advantages have been identified using this process as compared to conventional urgent CT simulation and delivery. Efficiency gains are notable, as physicians appreciate the predictable time commitment and patient waiting time for treatment is decreased. MR guidance in a treatment position offers both enhanced contrast for target delineation and reduction of setup uncertainties. The MRIdian system tools designed for adaptive radiotherapy are particularly useful, enabling plan changes to be made in minutes. Finally, the resulting plans, typically 6 conformal beams, are delivered as quickly as more conventional AP/PA beam arrangements with comparatively superior dose distributions. Conclusion: The ViewRay treatment planning software and

  9. Imaging of postthalamic visual fiber tracts by anisotropic diffusion weighted MRI and diffusion tensor imaging: principles and applications

    International Nuclear Information System (INIS)

    Reinges, Marcus H.T.; Schoth, Felix; Coenen, Volker A.; Krings, Timo

    2004-01-01

    Diffusion weighted MRI offers the possibility to study the course of the cerebral white matter tracts. In the present manuscript, the basics, the technique and the limitations of diffusion tensor imaging and anisotropic diffusion weighted MRI are presented and their applications in various neurological and neurosurgical diseases are discussed with special emphasis on the visual system. A special focus is laid on the combination of fiber tract imaging, anatomical imaging and functional MRI for presurgical planning and intraoperative neuronavigation of lesions near the visual system

  10. Imaging children suffering from lymphoma: an evaluation of different 18F-FDG PET/MRI protocols compared to whole-body DW-MRI.

    Science.gov (United States)

    Kirchner, Julian; Deuschl, Cornelius; Schweiger, Bernd; Herrmann, Ken; Forsting, Michael; Buchbender, Christian; Antoch, Gerald; Umutlu, Lale

    2017-09-01

    The objectives of this study were to evaluate and compare the diagnostic potential of different PET/MRI reading protocols, entailing non-enhanced / contrast-enhanced and diffusion-weighted 18 F-FDG PET/MR imaging and whole-body diffusion-weighted MRI for lesion detection and determination of the tumor stage in pediatric lymphoma patients. A total of 28 18 F-FDG PET/MRI datasets were included for analysis of four different reading protocols: (1) PET/MRI utilizing sole unenhanced T2w and T1w imaging, (2) PET/MRI utilizing additional contrast enhanced sequences, (3) PET/MR imaging utilizing unenhanced, contrast enhanced and DW imaging or (4) WB-DW-MRI. Statistical analyses were performed on a per-patient and a per-lesion basis. Follow-up and prior examinations as well as histopathology served as reference standards. PET/MRI correctly identified all 17 examinations with active lymphoma disease, while WB-DW-MRI correctly identified 15/17 examinations. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 96%, 96.5%, 97%, 95%, and 96% for PET/MRI 1 ; 97%, 96.5%, 97%, 96.5%, and 97% for PET/MRI 2 ; 97%, 96.5%, 97%, 96.5%, and 97% for PET/MRI 3 and 77%, 96%, 96%, 78.5% and 86% for MRI-DWI. 18 F-FDG PET/MRI is superior to WB-DW-MRI in staging pediatric lymphoma patients. Neither application of contrast media nor DWI leads to a noticeable improvement of the diagnostic accuracy of PET/MRI. Thus, unenhanced PET/MRI may play a crucial role for the diagnostic work-up of pediatric lymphoma patients in the future.

  11. Imaging children suffering from lymphoma: an evaluation of different {sup 18}F-FDG PET/MRI protocols compared to whole-body DW-MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kirchner, Julian; Buchbender, Christian; Antoch, Gerald [University Dusseldorf, Department of Diagnostic and Interventional Radiology, Medical Faculty, Dusseldorf (Germany); Deuschl, Cornelius; Schweiger, Bernd; Forsting, Michael; Umutlu, Lale [University Hospital Essen, University of Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany); Herrmann, Ken [University Hospital Essen, University of Duisburg-Essen, Department of Nuclear Medicine, Essen (Germany)

    2017-09-15

    The objectives of this study were to evaluate and compare the diagnostic potential of different PET/MRI reading protocols, entailing non-enhanced / contrast-enhanced and diffusion-weighted {sup 18}F-FDG PET/MR imaging and whole-body diffusion-weighted MRI for lesion detection and determination of the tumor stage in pediatric lymphoma patients. A total of 28 {sup 18}F-FDG PET/MRI datasets were included for analysis of four different reading protocols: (1) PET/MRI utilizing sole unenhanced T2w and T1w imaging, (2) PET/MRI utilizing additional contrast enhanced sequences, (3) PET/MR imaging utilizing unenhanced, contrast enhanced and DW imaging or (4) WB-DW-MRI. Statistical analyses were performed on a per-patient and a per-lesion basis. Follow-up and prior examinations as well as histopathology served as reference standards. PET/MRI correctly identified all 17 examinations with active lymphoma disease, while WB-DW-MRI correctly identified 15/17 examinations. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 96%, 96.5%, 97%, 95%, and 96% for PET/MRI{sub 1}; 97%, 96.5%, 97%, 96.5%, and 97% for PET/MRI{sub 2}; 97%, 96.5%, 97%, 96.5%, and 97% for PET/MRI{sub 3} and 77%, 96%, 96%, 78.5% and 86% for MRI-DWI. {sup 18}F-FDG PET/MRI is superior to WB-DW-MRI in staging pediatric lymphoma patients. Neither application of contrast media nor DWI leads to a noticeable improvement of the diagnostic accuracy of PET/MRI. Thus, unenhanced PET/MRI may play a crucial role for the diagnostic work-up of pediatric lymphoma patients in the future. (orig.)

  12. Synthese und Charakterisierung amphiphiler Porphyrinoide als Kontrastmittel für das Magnetic Resonance Imaging (MRI)

    OpenAIRE

    Neumann, Yvonne

    2011-01-01

    Magnetic resonance imaging (MRI) is a diagnostic tool, which is commonly used in visualization of internal procedures in the living tissue. Used in visualizing procedures, MRI shows an increased contrast-enhancing effect in soft tissue in contrast to other techniques like computer tomography (CT). MRI does not need any ionizing radiation and provides three dimensional tomographic shots. One of the first commonly used porphyrin-based contrast agents was Gadophrin-2, which has a high affinity t...

  13. Assessing the Accuracy and Reliability of Root Crack and Fracture Detection in Teeth Using Sweep Imaging with Fourier Transform (SWIFT) Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    Schuurmans, Tyler J.

    -delineated, high-signal (bright/white) line shape(s) that must be visible on multiple contiguous image slices. The line shape(s) must present as: single entities, or parallel pairs in close proximity, or pairs in close proximity exhibiting convergence or divergence extending from the external boundary of the tooth to the pulpal cavity. Intra-rater reliability for MRI was fair-to-almost perfect (kappa = 0.38-1.00) and for CBCT was moderate-to-almost perfect (kappa = 0.66-1.00). Inter-rater reliability for MRI was fair (kappa = 0.21; 95% CI: 0.10-0.31; p advantages of increased contrast and absence of artifact from radio-dense materials in MRI, comparable measures of sensitivity and specificity (in relation to CBCT) suggest quality MRI improvements are needed, specifically in image acquisition and post-processing parameters. Given the early stage of technology development and multiple available pathways to optimize MR imaging of teeth, there may be a use for SWIFT MRI in detecting cracks and fractures in teeth.

  14. Hyperpolarized 129Xe MRI: A viable functional lung imaging modality?

    International Nuclear Information System (INIS)

    Patz, Samuel; Hersman, F. William; Muradian, Iga; Hrovat, Mirko I.; Ruset, Iulian C.; Ketel, Stephen; Jacobson, Francine; Topulos, George P.; Hatabu, Hiroto; Butler, James P.

    2007-01-01

    The majority of researchers investigating hyperpolarized gas MRI as a candidate functional lung imaging modality have used 3 He as their imaging agent of choice rather than 129 Xe. This preference has been predominantly due to, 3 He providing stronger signals due to higher levels of polarization and higher gyromagnetic ratio, as well as its being easily available to more researchers due to availability of polarizers (USA) or ease of gas transport (Europe). Most researchers agree, however, that hyperpolarized 129 Xe will ultimately emerge as the imaging agent of choice due to its unlimited supply in nature and its falling cost. Our recent polarizer technology delivers vast improvements in hyperpolarized 129 Xe output. Using this polarizer, we have demonstrated the unique property of xenon to measure alveolar surface area noninvasively. In this article, we describe our human protocols and their safety, and our results for the measurement of the partial pressure of pulmonary oxygen (pO 2 ) by observation of 129 Xe signal decay. We note that the measurement of pO 2 by observation of 129 Xe signal decay is more complex than that for 3 He because of an additional signal loss mechanism due to interphase diffusion of 129 Xe from alveolar gas spaces to septal tissue. This results in measurements of an equivalent pO 2 that accounts for both traditional T 1 decay from pO 2 and that from interphase diffusion. We also provide an update on new technological advancements that form the foundation for an improved compact design polarizer as well as improvements that provide another order-of-magnitude scale-up in xenon polarizer output

  15. Contribution of brain imaging techniques: CT-scan and magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Pasco-Papon, A.; Gourdier, A.L.; Papon, X.; Caron-Poitreau, C.

    1996-01-01

    In light of the current lack of consensus on the benefit of carotid artery surgery to treat asymptomatic carotid artery stenosis, the decision to operate on a patient depends on individual evaluation and characterization of risk factors on carotid artery stenosis greater than 70 %. The assessment of such risk factors is based especially on non-invasive brain imaging techniques.Computed tomography scanning (CT-scan) and magnetic resonance imaging (MRI) enable two types of stenosis to be differentiated, i.e. stenoses which are symptomatic and those that are radiologically proven versus those which are clinically and radiologically silent. CT-scan investigation (with and without injection of iodinated contrast media) still continues to be a common routine test in 1996 whenever a surgical revascularization procedure is planned. The presence of deep lacunar infarcts ipsilateral to the carotid artery stenosis generally evidence the reality of stenosis and thus are useful to the surgeon in establishing whether surgery is indicated. In the absence a consensus on indications for surgical management, the surgeon could use the CT-scan and MRI as medicolegal records which could be compared to a subsequent postoperative CT-scan in case of ischemic complications associated with the surgical procedure. Furthermore, recent cerebral ischemia as evidenced by filling with contrast material, will call for postponing treatment by a few weeks. Although conventional MRI is more contributive than brain CT-scan in terms of sensibility and specificity, its indications are narrower because of its limited availability and cost constraints. But, development of angio-MRI and functional imaging promise that its future is assured and even perhaps as the sole diagnostic method if its indications are expanded to include preoperative angiographic evaluation of atheromatous lesions of supra-aortic trunks. (authors). 37 refs

  16. Modeling decision-making in single- and multi-modal medical images

    Science.gov (United States)

    Canosa, R. L.; Baum, K. G.

    2009-02-01

    This research introduces a mode-specific model of visual saliency that can be used to highlight likely lesion locations and potential errors (false positives and false negatives) in single-mode PET and MRI images and multi-modal fused PET/MRI images. Fused-modality digital images are a relatively recent technological improvement in medical imaging; therefore, a novel component of this research is to characterize the perceptual response to these fused images. Three different fusion techniques were compared to single-mode displays in terms of observer error rates using synthetic human brain images generated from an anthropomorphic phantom. An eye-tracking experiment was performed with naÃve (non-radiologist) observers who viewed the single- and multi-modal images. The eye-tracking data allowed the errors to be classified into four categories: false positives, search errors (false negatives never fixated), recognition errors (false negatives fixated less than 350 milliseconds), and decision errors (false negatives fixated greater than 350 milliseconds). A saliency model consisting of a set of differentially weighted low-level feature maps is derived from the known error and ground truth locations extracted from a subset of the test images for each modality. The saliency model shows that lesion and error locations attract visual attention according to low-level image features such as color, luminance, and texture.

  17. An MRI system for imaging neonates in the NICU: initial feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Tkach, Jean A.; Loew, Wolfgang; Pratt, Ron G.; Daniels, Barret R.; Giaquinto, Randy O.; Winter, Patrick M.; Li, Yu; Dumoulin, Charles L. [Cincinnati Children' s Hospital Medical Center, Imaging Research Center, Department of Radiology, Cincinnati, OH (United States); Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Hillman, Noah H.; Jobe, Alan H.; Kallapur, Suhas G.; Merhar, Stephanie L.; Ikegami, Machiko; Whitsett, Jeffrey A. [Perinatal Institute, Cincinnati Children' s Hospital Medical Center, Division of Neonatology and Pulmonary Biology, Cincinnati, OH (United States); Kline-Fath, Beth M. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2012-11-15

    Transporting premature infants from a neonatal intensive care unit (NICU) to a radiology department for MRI has medical risks and logistical challenges. To develop a small 1.5-T MRI system for neonatal imaging that can be easily installed in the NICU and to evaluate its performance using a sheep model of human prematurity. A 1.5-T MRI system designed for orthopedic use was adapted for neonatal imaging. The system was used for MRI examinations of the brain, chest and abdomen in 12 premature lambs during the first hours of life. Spin-echo, fast spin-echo and gradient-echo MR images were evaluated by two pediatric radiologists. All animals remained physiologically stable throughout the imaging sessions. Animals were imaged at two or three time points. Seven brain MRI examinations were performed in seven different animals, 23 chest examinations in 12 animals and 19 abdominal examinations in 11 animals. At each anatomical location, high-quality images demonstrating good spatial resolution, signal-to-noise ratio and tissue contrast were routinely obtained within 30 min using standard clinical protocols. Our preliminary experience demonstrates the feasibility and potential of the neonatal MRI system to provide state-of-the-art MRI capabilities within the NICU. Advantages include overall reduced cost and site demands, lower acoustic noise, improved ease of access and reduced medical risk to the neonate. (orig.)

  18. An MRI system for imaging neonates in the NICU: initial feasibility study

    International Nuclear Information System (INIS)

    Tkach, Jean A.; Loew, Wolfgang; Pratt, Ron G.; Daniels, Barret R.; Giaquinto, Randy O.; Winter, Patrick M.; Li, Yu; Dumoulin, Charles L.; Hillman, Noah H.; Jobe, Alan H.; Kallapur, Suhas G.; Merhar, Stephanie L.; Ikegami, Machiko; Whitsett, Jeffrey A.; Kline-Fath, Beth M.

    2012-01-01

    Transporting premature infants from a neonatal intensive care unit (NICU) to a radiology department for MRI has medical risks and logistical challenges. To develop a small 1.5-T MRI system for neonatal imaging that can be easily installed in the NICU and to evaluate its performance using a sheep model of human prematurity. A 1.5-T MRI system designed for orthopedic use was adapted for neonatal imaging. The system was used for MRI examinations of the brain, chest and abdomen in 12 premature lambs during the first hours of life. Spin-echo, fast spin-echo and gradient-echo MR images were evaluated by two pediatric radiologists. All animals remained physiologically stable throughout the imaging sessions. Animals were imaged at two or three time points. Seven brain MRI examinations were performed in seven different animals, 23 chest examinations in 12 animals and 19 abdominal examinations in 11 animals. At each anatomical location, high-quality images demonstrating good spatial resolution, signal-to-noise ratio and tissue contrast were routinely obtained within 30 min using standard clinical protocols. Our preliminary experience demonstrates the feasibility and potential of the neonatal MRI system to provide state-of-the-art MRI capabilities within the NICU. Advantages include overall reduced cost and site demands, lower acoustic noise, improved ease of access and reduced medical risk to the neonate. (orig.)

  19. An MRI system for imaging neonates in the NICU: initial feasibility study.

    Science.gov (United States)

    Tkach, Jean A; Hillman, Noah H; Jobe, Alan H; Loew, Wolfgang; Pratt, Ron G; Daniels, Barret R; Kallapur, Suhas G; Kline-Fath, Beth M; Merhar, Stephanie L; Giaquinto, Randy O; Winter, Patrick M; Li, Yu; Ikegami, Machiko; Whitsett, Jeffrey A; Dumoulin, Charles L

    2012-11-01

    Transporting premature infants from a neonatal intensive care unit (NICU) to a radiology department for MRI has medical risks and logistical challenges. To develop a small 1.5-T MRI system for neonatal imaging that can be easily installed in the NICU and to evaluate its performance using a sheep model of human prematurity. A 1.5-T MRI system designed for orthopedic use was adapted for neonatal imaging. The system was used for MRI examinations of the brain, chest and abdomen in 12 premature lambs during the first hours of life. Spin-echo, fast spin-echo and gradient-echo MR images were evaluated by two pediatric radiologists. All animals remained physiologically stable throughout the imaging sessions. Animals were imaged at two or three time points. Seven brain MRI examinations were performed in seven different animals, 23 chest examinations in 12 animals and 19 abdominal examinations in 11 animals. At each anatomical location, high-quality images demonstrating good spatial resolution, signal-to-noise ratio and tissue contrast were routinely obtained within 30 min using standard clinical protocols. Our preliminary experience demonstrates the feasibility and potential of the neonatal MRI system to provide state-of-the-art MRI capabilities within the NICU. Advantages include overall reduced cost and site demands, lower acoustic noise, improved ease of access and reduced medical risk to the neonate.

  20. Functional and magnetic resonance imaging evaluation after single-tendon rotator cuff reconstruction

    DEFF Research Database (Denmark)

    Knudsen, H B; Gelineck, J; Søjbjerg, Jens Ole

    1999-01-01

    The aim of this study was to investigate tendon integrity after surgical repair of single-tendon rotator cuff lesions. In 31 patients, 31 single-tendon repairs were evaluated. Thirty-one patients were available for clinical assessment and magnetic resonance imaging (MRI) at follow-up. A standard...... series of MR images was obtained for each. The results of functional assessment were scored according to the system of Constant. According to MRI evaluation, 21 (68%) patients had an intact or thinned rotator cuff and 10 (32%) had recurrence of a full-thickness cuff defect at follow-up. Patients...... with an intact or thinned rotator cuff had a median Constant score of 75.5 points; patients with a full-thickness cuff defect had a median score of 62 points. There was no correlation between tendon integrity on postoperative MR images and functional outcome. Patients with intact or thinned cuffs did not have...

  1. Exploiting Interslice Correlation for MRI Prostate Image Segmentation, from Recursive Neural Networks Aspect

    Directory of Open Access Journals (Sweden)

    Qikui Zhu

    2018-01-01

    Full Text Available Segmentation of the prostate from Magnetic Resonance Imaging (MRI plays an important role in prostate cancer diagnosis. However, the lack of clear boundary and significant variation of prostate shapes and appearances make the automatic segmentation very challenging. In the past several years, approaches based on deep learning technology have made significant progress on prostate segmentation. However, those approaches mainly paid attention to features and contexts within each single slice of a 3D volume. As a result, this kind of approaches faces many difficulties when segmenting the base and apex of the prostate due to the limited slice boundary information. To tackle this problem, in this paper, we propose a deep neural network with bidirectional convolutional recurrent layers for MRI prostate image segmentation. In addition to utilizing the intraslice contexts and features, the proposed model also treats prostate slices as a data sequence and utilizes the interslice contexts to assist segmentation. The experimental results show that the proposed approach achieved significant segmentation improvement compared to other reported methods.

  2. Multimodal in vivo MRI and NIRF imaging of bladder tumor using peptide conjugated glycol chitosan nanoparticles

    Science.gov (United States)

    Key, Jaehong; Dhawan, Deepika; Knapp, Deborah W.; Kim, Kwangmeyung; Kwon, Ick Chan; Choi, Kuiwon; Leary, James F.

    2012-03-01

    Exact detection and complete removal of cancer is a key point to minimize cancer recurrence. However, it is currently very difficult to detect small tumors inside human body and continuously monitor tumors using a non-invasive imaging modality. Presently, positron emission tomography (PET) can provide the most sensitive cancer images in the human body. However, PET imaging has very limited imaging time because they typically use isotopes with short halflives. PET imaging cannot also visualize anatomical information. Magnetic resonance imaging (MRI) can provide highresolution images inside the body but it has a low sensitivity, so MRI contrast agents are necessary to enhance the contrast of tumor. Near infrared fluorescent (NIRF) imaging has a good sensitivity to visualize tumor using optical probes, but it has a very limited tissue penetration depth. Therefore, we developed multi-modality nanoparticles for MRI based diagnosis and NIRF imaging based surgery of cancer. We utilized glycol chitosan of 350 nm as a vehicle for MRI contrast agents and NIRF probes. The glycol chitosan nanoparticles were conjugated with NIRF dye, Cy5.5 and bladder cancer targeting peptides to increase the internalization of cancer. For MR contrast effects, iron oxide based 22 nm nanocubes were physically loaded into the glycol chitosan nanoparticles. The nanoparticles were characterized and evaluated in bladder tumor bearing mice. Our study suggests the potential of our nanoparticles by both MRI and NIRF imaging for tumor diagnosis and real-time NIRF image-guided tumor surgery.

  3. Comparison between target magnetic resonance imaging (MRI) in-gantry and cognitively directed transperineal or transrectal-guided prostate biopsies for Prostate Imaging-Reporting and Data System (PI-RADS) 3-5 MRI lesions.

    Science.gov (United States)

    Yaxley, Anna J; Yaxley, John W; Thangasamy, Isaac A; Ballard, Emma; Pokorny, Morgan R

    2017-11-01

    To compare the detection rates of prostate cancer (PCa) in men with Prostate Imaging-Reporting and Data System (PI-RADS) 3-5 abnormalities on 3-Tesla multiparametric (mp) magnetic resonance imaging (MRI) using in-bore MRI-guided biopsy compared with cognitively directed transperineal (cTP) biopsy and transrectal ultrasonography (cTRUS) biopsy. This was a retrospective single-centre study of consecutive men attending the private practice clinic of an experienced urologist performing MRI-guided biopsy and an experienced urologist performing cTP and cTRUS biopsy techniques for PI-RADS 3-5 lesions identified on 3-Tesla mpMRI. There were 595 target mpMRI lesions from 482 men with PI-RADS 3-5 regions of interest during 483 episodes of biopsy. The abnormal mpMRI target lesion was biopsied using the MRI-guided method for 298 biopsies, the cTP method for 248 biopsies and the cTRUS method for 49 biopsies. There were no significant differences in PCa detection among the three biopsy methods in PI-RADS 3 (48.9%, 40.0% and 44.4%, respectively), PI-RADS 4 (73.2%, 81.0% and 85.0%, respectively) or PI-RADS 5 (95.2, 92.0% and 95.0%, respectively) lesions, and there was no significant difference in detection of significant PCa among the biopsy methods in PI-RADS 3 (42.2%, 30.0% and 33.3%, respectively), PI-RADS 4 (66.8%, 66.0% and 80.0%, respectively) or PI-RADS 5 (90.5%, 89.8% and 90.0%, respectively) lesions. There were also no differences in PCa or significant PCa detection based on lesion location or size among the methods. We found no significant difference in the ability to detect PCa or significant PCa using targeted MRI-guided, cTP or cTRUS biopsy methods. Identification of an abnormal area on mpMRI appears to be more important in increasing the detection of PCa than the technique used to biopsy an MRI abnormality. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

  4. Phase-encoded MRI for geometrically undistorted imaging and signal characterization

    NARCIS (Netherlands)

    van Gorp, JS

    2016-01-01

    Magnetic resonance imaging (MRI) is a versatile diagnostic modality that has earned its place in clinical practice all over the world. MRI delivers excellent soft-tissue contrast that can be utilized to detect disease and measure physiological properties in a non-invasive manner. As long as the main

  5. Cortical phase changes in Alzheimer's disease at 7T MRI: a novel imaging marker

    NARCIS (Netherlands)

    van Rooden, S.; Versluis, M.J.; Liem, M.K.; Milles, J.; Maier, A.B.; Oleksik, A.M.; Webb, A.G.; van Buchem, M.A.; van der Grond, J.

    2014-01-01

    Background: Postmortem studies have indicated the potential of high-field magnetic resonance imaging (MRI) to visualize amyloid depositions in the cerebral cortex. The aim of this study is to test this hypothesis in patients with Alzheimer's disease (AD). Methods: T2*-weighted MRI was performed in

  6. The OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging (MRI) Scoring System: Updated Recommendations by the OMERACT MRI in Arthritis Working Group.

    Science.gov (United States)

    Østergaard, Mikkel; Peterfy, Charles G; Bird, Paul; Gandjbakhch, Frédérique; Glinatsi, Daniel; Eshed, Iris; Haavardsholm, Espen A; Lillegraven, Siri; Bøyesen, Pernille; Ejbjerg, Bo; Foltz, Violaine; Emery, Paul; Genant, Harry K; Conaghan, Philip G

    2017-11-01

    The Outcome Measures in Rheumatology (OMERACT) Rheumatoid Arthritis (RA) Magnetic Resonance Imaging (MRI) scoring system (RAMRIS), evaluating bone erosion, bone marrow edema/osteitis, and synovitis, was introduced in 2002, and is now the standard method of objectively quantifying inflammation and damage by MRI in RA trials. The objective of this paper was to identify subsequent advances and based on them, to provide updated recommendations for the RAMRIS. MRI studies relevant for RAMRIS and technical and scientific advances were analyzed by the OMERACT MRI in Arthritis Working Group, which used these data to provide updated considerations on image acquisition, RAMRIS definitions, and scoring systems for the original and new RA pathologies. Further, a research agenda was outlined. Since 2002, longitudinal studies and clinical trials have documented RAMRIS variables to have face, construct, and criterion validity; high reliability and sensitivity to change; and the ability to discriminate between therapies. This has enabled RAMRIS to demonstrate inhibition of structural damage progression with fewer patients and shorter followup times than has been possible with conventional radiography. Technical improvements, including higher field strengths and improved pulse sequences, allow higher image resolution and contrast-to-noise ratio. These have facilitated development and validation of scoring methods of new pathologies: joint space narrowing and tenosynovitis. These have high reproducibility and moderate sensitivity to change, and can be added to RAMRIS. Combined scores of inflammation or joint damage may increase sensitivity to change and discriminative power. However, this requires further research. Updated 2016 RAMRIS recommendations and a research agenda were developed.

  7. Can multi-slice or navigator-gated R2* MRI replace single-slice breath-hold acquisition for hepatic iron quantification?

    International Nuclear Information System (INIS)

    Loeffler, Ralf B.; McCarville, M.B.; Song, Ruitian; Hillenbrand, Claudia M.; Wagstaff, Anne W.; Smeltzer, Matthew P.; Krafft, Axel J.; Hankins, Jane S.

    2017-01-01

    Liver R2* values calculated from multi-gradient echo (mGRE) magnetic resonance images (MRI) are strongly correlated with hepatic iron concentration (HIC) as shown in several independently derived biopsy calibration studies. These calibrations were established for axial single-slice breath-hold imaging at the location of the portal vein. Scanning in multi-slice mode makes the exam more efficient, since whole-liver coverage can be achieved with two breath-holds and the optimal slice can be selected afterward. Navigator echoes remove the need for breath-holds and allow use in sedated patients. To evaluate if the existing biopsy calibrations can be applied to multi-slice and navigator-controlled mGRE imaging in children with hepatic iron overload, by testing if there is a bias-free correlation between single-slice R2* and multi-slice or multi-slice navigator controlled R2*. This study included MRI data from 71 patients with transfusional iron overload, who received an MRI exam to estimate HIC using gradient echo sequences. Patient scans contained 2 or 3 of the following imaging methods used for analysis: single-slice images (n = 71), multi-slice images (n = 69) and navigator-controlled images (n = 17). Small and large blood corrected region of interests were selected on axial images of the liver to obtain R2* values for all data sets. Bland-Altman and linear regression analysis were used to compare R2* values from single-slice images to those of multi-slice images and navigator-controlled images. Bland-Altman analysis showed that all imaging method comparisons were strongly associated with each other and had high correlation coefficients (0.98 ≤ r ≤ 1.00) with P-values ≤0.0001. Linear regression yielded slopes that were close to 1. We found that navigator-gated or breath-held multi-slice R2* MRI for HIC determination measures R2* values comparable to the biopsy-validated single-slice, single breath-hold scan. We conclude that these three R2* methods can be

  8. Can multi-slice or navigator-gated R2* MRI replace single-slice breath-hold acquisition for hepatic iron quantification?

    Energy Technology Data Exchange (ETDEWEB)

    Loeffler, Ralf B.; McCarville, M.B.; Song, Ruitian; Hillenbrand, Claudia M. [St. Jude Children' s Research Hospital, Diagnostic Imaging, Memphis, TN (United States); Wagstaff, Anne W. [St. Jude Children' s Research Hospital, Diagnostic Imaging, Memphis, TN (United States); Rhodes College, Memphis, TN (United States); University of Alabama at Birmingham School of Medicine, Birmingham, AL (United States); Smeltzer, Matthew P. [St. Jude Children' s Research Hospital, Department of Biostatistics, Memphis, TN (United States); University of Memphis, Division of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, Memphis, TN (United States); Krafft, Axel J. [St. Jude Children' s Research Hospital, Diagnostic Imaging, Memphis, TN (United States); University Hospital Center Freiburg, Department of Radiology, Freiburg (Germany); Hankins, Jane S. [St. Jude Children' s Research Hospital, Department of Hematology, Memphis, TN (United States)

    2017-01-15

    Liver R2* values calculated from multi-gradient echo (mGRE) magnetic resonance images (MRI) are strongly correlated with hepatic iron concentration (HIC) as shown in several independently derived biopsy calibration studies. These calibrations were established for axial single-slice breath-hold imaging at the location of the portal vein. Scanning in multi-slice mode makes the exam more efficient, since whole-liver coverage can be achieved with two breath-holds and the optimal slice can be selected afterward. Navigator echoes remove the need for breath-holds and allow use in sedated patients. To evaluate if the existing biopsy calibrations can be applied to multi-slice and navigator-controlled mGRE imaging in children with hepatic iron overload, by testing if there is a bias-free correlation between single-slice R2* and multi-slice or multi-slice navigator controlled R2*. This study included MRI data from 71 patients with transfusional iron overload, who received an MRI exam to estimate HIC using gradient echo sequences. Patient scans contained 2 or 3 of the following imaging methods used for analysis: single-slice images (n = 71), multi-slice images (n = 69) and navigator-controlled images (n = 17). Small and large blood corrected region of interests were selected on axial images of the liver to obtain R2* values for all data sets. Bland-Altman and linear regression analysis were used to compare R2* values from single-slice images to those of multi-slice images and navigator-controlled images. Bland-Altman analysis showed that all imaging method comparisons were strongly associated with each other and had high correlation coefficients (0.98 ≤ r ≤ 1.00) with P-values ≤0.0001. Linear regression yielded slopes that were close to 1. We found that navigator-gated or breath-held multi-slice R2* MRI for HIC determination measures R2* values comparable to the biopsy-validated single-slice, single breath-hold scan. We conclude that these three R2* methods can be

  9. Prospective MR image alignment between breath-holds: Application to renal BOLD MRI.

    Science.gov (United States)

    Kalis, Inge M; Pilutti, David; Krafft, Axel J; Hennig, Jürgen; Bock, Michael

    2017-04-01

    To present an image registration method for renal blood oxygen level-dependent (BOLD) measurements that enables semiautomatic assessment of parenchymal and medullary R2* changes under a functional challenge. In a series of breath-hold acquisitions, three-dimensional data were acquired initially for prospective image registration of subsequent BOLD measurements. An algorithm for kidney alignment for BOLD renal imaging (KALIBRI) was implemented to detect the positions of the left and right kidney so that the kidneys were acquired in the subsequent BOLD measurement at consistent anatomical locations. Residual in-plane distortions were corrected retrospectively so that semiautomatic dynamic R2* measurements of the renal cortex and medulla become feasible. KALIBRI was tested in six healthy volunteers during a series of BOLD experiments, which included a 600- to 1000-mL water challenge. Prospective image registration and BOLD imaging of each kidney was achieved within a total measurement time of about 17 s, enabling its execution within a single breath-hold. KALIBRI improved the registration by up to 35% as found with mutual information measures. In four volunteers, a medullary R2* decrease of up to 40% was observed after water ingestion. KALIBRI improves the quality of two-dimensional time-resolved renal BOLD MRI by aligning local renal anatomy, which allows for consistent R2* measurements over many breath-holds. Magn Reson Med 77:1573-1582, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  10. Indications and value of bone scintigraphy in comparison to magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Haug, A.; Hacker, M.; Weiss, M.; Hahn, K.; Pfluger, T.

    2006-01-01

    With increasing use of cross-sectional imaging (CT/MRI) in radiology as well as PET and PET/CT in nuclear medicine, remaining indications for bone scintigraphy are in question. Recently introduced whole-body MRI represents an attractive alternative to bone scintigraphy, as MRI is additionally able to assess lesions that are limited to bone marrow and are located extraosseously. In this overview, indication-related strengths and limitations of MRI and bone scintigraphy are presented and discussed. Furthermore, complementary use of both modalities for special clinical questions is demonstrated. (orig.)

  11. Structural Image Analysis of the Brain in Neuropsychology Using Magnetic Resonance Imaging (MRI) Techniques.

    Science.gov (United States)

    Bigler, Erin D

    2015-09-01

    Magnetic resonance imaging (MRI) of the brain provides exceptional image quality for visualization and neuroanatomical classification of brain structure. A variety of image analysis techniques provide both qualitative as well as quantitative methods to relate brain structure with neuropsychological outcome and are reviewed herein. Of particular importance are more automated methods that permit analysis of a broad spectrum of anatomical measures including volume, thickness and shape. The challenge for neuropsychology is which metric to use, for which disorder and the timing of when image analysis methods are applied to assess brain structure and pathology. A basic overview is provided as to the anatomical and pathoanatomical relations of different MRI sequences in assessing normal and abnormal findings. Some interpretive guidelines are offered including factors related to similarity and symmetry of typical brain development along with size-normalcy features of brain anatomy related to function. The review concludes with a detailed example of various quantitative techniques applied to analyzing brain structure for neuropsychological outcome studies in traumatic brain injury.

  12. Defining active sacroiliitis on magnetic resonance imaging (MRI) for classification of axial spondyloarthritis: a consensual approach by the ASAS/OMERACT MRI group

    NARCIS (Netherlands)

    Rudwaleit, M.; Jurik, A. G.; Hermann, K.-G. A.; Landewé, R.; van der Heijde, D.; Baraliakos, X.; Marzo-Ortega, H.; Ostergaard, M.; Braun, J.; Sieper, J.

    2009-01-01

    Magnetic resonance imaging (MRI) of sacroiliac joints has evolved as the most relevant imaging modality for diagnosis and classification of early axial spondyloarthritis (SpA) including early ankylosing spondylitis. To identify and describe MRI findings in sacroiliitis and to reach consensus on

  13. Comparison of multi-echo and single-echo gradient-recalled echo sequences for SPIO-enhanced Liver MRI at 3 T

    International Nuclear Information System (INIS)

    Choi, J.S.; Kim, M.-J.; Kim, J.H.; Choi, J.-Y.; Chung, Y.E.; Park, M.-S.; Kim, K.W.

    2010-01-01

    Aim: To assess the utility of a T2*-weighted, multi-echo data imaging combination sequenced on superparamagnetic iron oxide (SPIO)-enhanced liver magnetic resonance imaging (MRI) using a 3 T system. Materials and methods: Fifty patients underwent SPIO-enhanced MRI at 3 T using T2*-weighted, single-echo, gradient-recalled echo (GRE) sequences [fast imaging with steady precession; repetition time (TR)/echo time (TE), 126 ms/9 ms; flip angle, 30 o ] and multi-echo GRE (multi-echo data image combination) sequences (TR/TE, 186 ms/9 ms; flip angle, 30 o ). Three radiologists independently reviewed the images in a random order. The sensitivity and accuracy for the detection of focal hepatic lesions (a total of 76 lesions in 33 patients; 48 solid lesions, 28 non-solid lesions) were compared by analysing the area under the receiver operating characteristic curves. Image artefacts (flow artefacts, susceptibility artefacts, dielectric artefacts, and motion artefacts), lesion conspicuity, and overall image quality were evaluated according to a four-point scale: 1, poor; 2, fair; 3, good; 4, excellent. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the lesions were compared. Results: Image artefacts were more frequent with single-echo GRE (p < 0.05). The mean scale of image quality assessment for flow, susceptibility, dielectric, and motion artefacts were 2.76, 3.13, 3.42, and 2.89 with singe-echo, respectively, compared with 3.47, 3.43, 3.47, and 3.39, respectively, with multi-echo GRE. There was no significant difference in lesion conspicuity between single-echo (3.15) and multi-echo (3.30) GRE sequences. The overall image quality was significantly (p < 0.05) better with multi-echo (3.37) than with single-echo GRE (2.89). The mean SNR and CNR of the lesions were significantly (p < 0.05) higher on multi-echo (79 ± 23 and 128 ± 59, respectively) images than on single-echo (38 ± 11 and 102 ± 44, respectively) images. Lesion detection accuracy and

  14. Whole-body MRI in adult inflammatory myopathies: Do we need imaging of the trunk?

    International Nuclear Information System (INIS)

    Filli, Lukas; Manoliu, Andrei; Andreisek, Gustav; Guggenberger, Roman; Maurer, Britta

    2015-01-01

    To evaluate whether imaging of the trunk could be omitted in patients with inflammatory myopathies without losing diagnostic accuracy using a restricted whole-body magnetic resonance imaging (rWB-MRI) protocol. After approval by the institutional review board, this study was performed in 63 patients (male/female, 13/50; median age, 52 years; range, 20-81 years) with new-onset myopathic symptoms (group 1, n = 41) or previously diagnosed inflammatory myopathy (group 2, n = 22). After performing whole-body MRI (WB-MRI) at 3.0 Tesla, myositis and fatty atrophy were evaluated in different muscles by two independent radiologists. The intra-class correlation coefficient (ICC) was calculated to evaluate inter-observer reliability. Acquisition time was 56:01 minutes for WB-MRI and 37:37 minutes (32.8 % shorter) for rWB-MRI. In group 1, 14 patients were diagnosed with inflammatory myopathy based on muscle biopsy. rWB-MRI and WB-MRI showed equal sensitivity (42.9 %) and specificity (100 %) for myositis, and showed equal sensitivity (71.4 %) and similar specificity (63.0 % and 48.1 %, respectively) for fatty atrophy. No myositis was found in the body trunk in any patient. Inter-observer reliability was between substantial and perfect (ICC, 0.77-1.00). rWB-MRI showed diagnostic accuracy similar to WB-MRI for inflammatory myopathy at markedly reduced overall acquisition time. (orig.)

  15. Whole-body MRI in adult inflammatory myopathies: Do we need imaging of the trunk?

    Energy Technology Data Exchange (ETDEWEB)

    Filli, Lukas; Manoliu, Andrei; Andreisek, Gustav; Guggenberger, Roman [University Hospital Zurich, University of Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Maurer, Britta [University Hospital Zurich, University of Zurich, Division of Rheumatology, Zurich (Switzerland)

    2015-12-15

    To evaluate whether imaging of the trunk could be omitted in patients with inflammatory myopathies without losing diagnostic accuracy using a restricted whole-body magnetic resonance imaging (rWB-MRI) protocol. After approval by the institutional review board, this study was performed in 63 patients (male/female, 13/50; median age, 52 years; range, 20-81 years) with new-onset myopathic symptoms (group 1, n = 41) or previously diagnosed inflammatory myopathy (group 2, n = 22). After performing whole-body MRI (WB-MRI) at 3.0 Tesla, myositis and fatty atrophy were evaluated in different muscles by two independent radiologists. The intra-class correlation coefficient (ICC) was calculated to evaluate inter-observer reliability. Acquisition time was 56:01 minutes for WB-MRI and 37:37 minutes (32.8 % shorter) for rWB-MRI. In group 1, 14 patients were diagnosed with inflammatory myopathy based on muscle biopsy. rWB-MRI and WB-MRI showed equal sensitivity (42.9 %) and specificity (100 %) for myositis, and showed equal sensitivity (71.4 %) and similar specificity (63.0 % and 48.1 %, respectively) for fatty atrophy. No myositis was found in the body trunk in any patient. Inter-observer reliability was between substantial and perfect (ICC, 0.77-1.00). rWB-MRI showed diagnostic accuracy similar to WB-MRI for inflammatory myopathy at markedly reduced overall acquisition time. (orig.)

  16. Reducing sedation for pediatric body MRI using accelerated and abbreviated imaging protocols

    International Nuclear Information System (INIS)

    Ahmad, Rizwan; Hu, Houchun Harry; Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh

    2018-01-01

    Magnetic resonance imaging (MRI) is an established diagnostic imaging tool for investigating pediatric disease. MRI allows assessment of structure, function, and morphology in cardiovascular imaging, as well as tissue characterization in body imaging, without the use of ionizing radiation. For MRI in children, sedation and general anesthesia (GA) are often utilized to suppress patient motion, which can otherwise compromise image quality and diagnostic efficacy. However, evidence is emerging that use of sedation and GA in children might have long-term neurocognitive side effects, in addition to the short-term procedure-related risks. These concerns make risk-benefit assessment of sedation and GA more challenging. Therefore, reducing or eliminating the need for sedation and GA is an important goal of imaging innovation and research in pediatric MRI. In this review, the authors focus on technical and clinical approaches to reducing and eliminating the use of sedation in the pediatric population based on image acquisition acceleration and imaging protocols abbreviation. This paper covers important physiological and technical considerations for pediatric body MR imaging and discusses MRI techniques that offer the potential of recovering diagnostic-quality images from accelerated scans. In this review, the authors also introduce the concept of reporting elements for important indications for pediatric body MRI and use this as a basis for abbreviating the MR protocols. By employing appropriate accelerated and abbreviated approaches based on an understanding of the imaging needs and reporting elements for a given clinical indication, it is possible to reduce sedation and GA for pediatric chest, cardiovascular and abdominal MRI. (orig.)

  17. Rapid ex vivo imaging of PAIII prostate to bone tumor with SWIFT-MRI.

    Science.gov (United States)

    Luhach, Ihor; Idiyatullin, Djaudat; Lynch, Conor C; Corum, Curt; Martinez, Gary V; Garwood, Michael; Gillies, Robert J

    2014-09-01

    The limiting factor for MRI of skeletal/mineralized tissue is fast transverse relaxation. A recent advancement in MRI technology, SWIFT (Sweep Imaging with Fourier Transform), is emerging as a new approach to overcome this difficulty. Among other techniques like UTE, ZTE, and WASPI, the application of SWIFT technology has the strong potential to impact preclinical and clinical imaging, particularly in the context of primary or metastatic bone cancers because it has the added advantage of imaging water in mineralized tissues of bone allowing MRI images to be obtained of tissues previously visible only with modalities such as computed tomography (CT). The goal of the current study is to examine the feasibility of SWIFT for the assessment of the prostate cancer induced changes in bone formation (osteogenesis) and destruction (osteolysis) in ex vivo specimens. A luciferase expressing prostate cancer cell line (PAIII) or saline control was inoculated directly into the tibia of 6-week-old immunocompromised male mice. Tumor growth was assessed weekly for 3 weeks before euthanasia and dissection of the tumor bearing and sham tibias. The ex vivo mouse tibia specimens were imaged with a 9.4 Tesla (T) and 7T MRI systems. SWIFT images are compared with traditional gradient-echo and spin-echo MRI images as well as CT and histological sections. SWIFT images with nominal resolution of 78 μm are obtained with the tumor and different bone structures identified. Prostate cancer induced changes in the bone microstructure are visible in SWIFT images, which is supported by spin-echo, high resolution CT and histological analysis. SWIFT MRI is capable of high-quality high-resolution ex vivo imaging of bone tumor and surrounding bone and soft tissues. Furthermore, SWIFT MRI shows promise for in vivo bone tumor imaging, with the added benefits of nonexposure to ionizing radiation, quietness, and speed. Copyright © 2013 Wiley Periodicals, Inc.

  18. Reducing sedation for pediatric body MRI using accelerated and abbreviated imaging protocols

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Rizwan [The Ohio State University, Department of Biomedical Engineering, Columbus, OH (United States); Hu, Houchun Harry; Krishnamurthy, Ramkumar; Krishnamurthy, Rajesh [Nationwide Children' s Hospital, Department of Radiology, Columbus, OH (United States)

    2018-01-15

    Magnetic resonance imaging (MRI) is an established diagnostic imaging tool for investigating pediatric disease. MRI allows assessment of structure, function, and morphology in cardiovascular imaging, as well as tissue characterization in body imaging, without the use of ionizing radiation. For MRI in children, sedation and general anesthesia (GA) are often utilized to suppress patient motion, which can otherwise compromise image quality and diagnostic efficacy. However, evidence is emerging that use of sedation and GA in children might have long-term neurocognitive side effects, in addition to the short-term procedure-related risks. These concerns make risk-benefit assessment of sedation and GA more challenging. Therefore, reducing or eliminating the need for sedation and GA is an important goal of imaging innovation and research in pediatric MRI. In this review, the authors focus on technical and clinical approaches to reducing and eliminating the use of sedation in the pediatric population based on image acquisition acceleration and imaging protocols abbreviation. This paper covers important physiological and technical considerations for pediatric body MR imaging and discusses MRI techniques that offer the potential of recovering diagnostic-quality images from accelerated scans. In this review, the authors also introduce the concept of reporting elements for important indications for pediatric body MRI and use this as a basis for abbreviating the MR protocols. By employing appropriate accelerated and abbreviated approaches based on an understanding of the imaging needs and reporting elements for a given clinical indication, it is possible to reduce sedation and GA for pediatric chest, cardiovascular and abdominal MRI. (orig.)

  19. Prospective assessment of MRI for imaging retroperitoneal metastases from testicular germ cell tumours

    Energy Technology Data Exchange (ETDEWEB)

    Sohaib, S.A. [Department of Radiology, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey (United Kingdom)], E-mail: aslam.sohaib@rmh.nhs.uk; Koh, D.M. [Department of Radiology, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey (United Kingdom); Barbachano, Y. [Department of Computing and Statistics, Royal Marsden Hospital, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey (United Kingdom); Parikh, J.; Husband, J.E.S. [Department of Radiology, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey (United Kingdom); Dearnaley, D.P.; Horwich, A.; Huddart, R. [Department of Academic Urology Unit, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey (United Kingdom)

    2009-04-15

    Aim: To determine the sensitivity of magnetic resonance imaging (MRI) in the detection of retroperitoneal lymph nodes in patients with testicular germ cell tumours (TGCT). Methods and materials: A prospective study of 52 patients (mean age 34 years, range 18-54 years) was performed. Imaging of the retroperitoneum was performed using multidetector computed tomography (CT) and 1.5 T MRI systems. The CT and MRI images were read independently by three observers. The number, size, and site of enlarged nodes ({>=}10 mm maximum short axis diameter) were recorded. Retroperitoneal nodal detection on MRI was compared to CT. Results: Twenty-two (42%) of the 52 patients had no retroperitoneal disease; in remaining 30 patients 51 enlarged nodes were identified. On a per patient basis readers 1, 2, and 3 identified nodal disease in 28 of 29, 29 of 30, and 24 of 30 patients, respectively, using MRI compared to CT. Thus for experienced radiologists (readers 1 and 2) MRI is comparable to CT for nodal detection (i.e., this study excludes MRI being inferior to CT with 80% power and 5% type 1 error). Conclusion: MRI offers an alternative method for staging the retroperitoneum in young patients being followed for TGCT and has the major advantage of avoiding exposure to ionizing radiation.

  20. Design and implementation of a simple multinuclear MRI system for ultra high-field imaging of animals

    Science.gov (United States)

    Choi, Chang-Hoon; Ha, YongHyun; Veeraiah, Pandichelvam; Felder, Jörg; Möllenhoff, Klaus; Shah, N. Jon

    2016-12-01

    Non-proton MRI has recently garnered gathering interest with the increased availability of ultra high-field MRI system. Assuming the availability of a broadband RF amplifier, performing multinuclear MR experiments essentially requires additional hardware, such as an RF resonator and a T/R switch for each nucleus. A double- or triple-resonant RF probe is typically constructed using traps or PIN-diode circuits, but this approach degrades the signal-to-noise ratio (SNR) and image quality compared to a single-resonant coil and this is a limiting factor. In this work, we have designed the required hardware for multinuclear MR imaging experiments employing six single-resonant coil sets and a purpose-built animal bed; these have been implemented into a home-integrated 9.4 T preclinical MRI scanner. System capabilities are demonstrated by distinguishing concentration differences and sensitivity of X-nuclei imaging and spectroscopy without SNR penalty for any nuclei, no subject interruption and no degradation of the static shim conditions.

  1. Measurement and imaging of brain function using MRI, MEG, and TMS

    International Nuclear Information System (INIS)

    Iramina, Keiji

    2008-01-01

    This paper reviews functional imaging techniques in neuroscience such as magnetic resonance imaging (MRI) functional MRI (fMRI), magnetoencephalogray (MEG), and transcranial magnetic stimulation (TMS). fMRI and MEG allow the neuronal activity of the brain to be measured non-invasively. MEG detects an electrical activity as neuronal activity, while, fMRI detects a hemodynamic response as neuronal activity. TMS is the application of a brief magnetic pulse or a train of pulses to the skull, which results in the induction of a local electric current in the underlying surface of the brain, thereby producing a localized axonal depolarization. As a non-invasive and effective method to make reversible lesions in the human brain, TMS has a long and successful history. All of these techniques have major potential for applications in the neuroscience and medicine. (author)

  2. MRI evaluation following partial HIFU therapy for localized prostate cancer: A single-center study.

    Science.gov (United States)

    Hoquetis, L; Malavaud, B; Game, X; Beauval, J B; Portalez, D; Soulie, M; Rischmann, P

    2016-09-01

    To evaluate the value of MRI for surveillance of primary hemi-HIFU therapy for localized PCa in a single-center. Patients with localized prostate cancer were treated with hemi-HIFU from October 2009 to March 2014. All patients performed MRI before focal therapy, the reader was blinded to the treatment. Oncological failure was defined as positive biopsy or biochemical recurrence (Phoenix). Twenty-five patients were treated with hemi-HIFU in one center. The median nadir PSA was 1.45±1.4ng/mL. Prostate volume decreased from 45 cc to 25 cc on MRI findings. At 20 months, none of the patients had histological recurrence. Biochemical-free survival rate was 88%. MRI evaluation had a negative predictive value of 100% on the treated area and 81% on the untreated area. PSAd≥0.1ng/mL(2) was a predictive factor for cancer on untreated area (P=0.042). MRI control at 6 months is a potentially effective evaluation of treated area after hemi-HIFU and may replace randomized biopsies if PSAd<0.1ng/mL(2) during follow-up. 4. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. Image artifacts from MR-based attenuation correction in clinical, whole-body PET/MRI

    DEFF Research Database (Denmark)

    Keller, Sune H; Holm, Søren; Hansen, Adam E

    2013-01-01

    Integrated whole-body PET/MRI tomographs have become available. PET/MR imaging has the potential to supplement, or even replace combined PET/CT imaging in selected clinical indications. However, this is true only if methodological pitfalls and image artifacts arising from novel MR-based attenuation...

  4. MRI of the scrotum. Recommendations of the ESUR Scrotal and Penile Imaging Working Group

    Energy Technology Data Exchange (ETDEWEB)

    Tsili, Athina C.; Ntorkou, Alexandra [University of Ioannina, Department of Clinical Radiology, Medical School, Ioannina (Greece); Bertolotto, Michele [Uco di Radiologia, Trieste Univ. (Italy); Turgut, Ahmet Tuncay [Ankara Training and Research Hospital, Department of Radiology, Ankara (Turkey); Dogra, Vikram [University of Rochester School of Medicine and Dentistry, Department of Imaging Sciences, Rochester, NY (United States); Freeman, Simon [Plymouth Hospitals NHS Trust, Plymouth (United Kingdom); Rocher, Laurence [Hopitaux Universitaires Paris Sud, APHP, Ecole Doctorale Biosigne, Le Kremlin Bicetre (France); Belfield, Jane [Royal Liverpool University Hospital, Liverpool (United Kingdom); Studniarek, Michal [Medical University of Gdansk, Gdansk (Poland); Derchi, Lorenzo E. [Universita di Genova, Genova (Italy); Oyen, Raymond [KU Leuven, Radiology, Leuven (Belgium); Ramchandani, Parvati [Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA (United States); Secil, Mustafa [Dokuz Eylul University Faculty of Medicine, Department of Radiology, Izmir (Turkey); Richenberg, Jonathan [Royal Sussex County Hospital Brighton and Brighton and Sussex Medical School, Brighton, Sussex (United Kingdom)

    2018-01-15

    The Scrotal and Penile Imaging Working Group (SPI-WG) appointed by the board of the European Society of Urogenital Radiology (ESUR) has produced recommendations for magnetic resonance imaging (MRI) of the scrotum. The SPI-WG searched for original and review articles published before September 2016 using the Pubmed and Medline databases. Keywords used were 'magnetic resonance imaging', 'testis or testicle or testicular', 'scrotum', 'intratesticular', 'paratesticular', 'extratesticular' 'diffusion-weighted', 'dynamic MRI'. Consensus was obtained among the members of the subcommittee. The expert panel proposed recommendations using Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence. The recommended MRI protocol should include T1-, T2-weighted imaging, diffusion-weighted imaging and dynamic contrast-enhanced MRI. Scrotal MRI can be clinically applied for lesion characterisation (primary), including both intratesticular and paratesticular masses, differentiation between germ-cell and non-germ-cell neoplasms (evolving), characterisation of the histological type of testicular germ cell neoplasms (TGCNs, in selected cases), local staging of TGCNs (primary), acute scrotum (in selected cases), trauma (in selected cases) and undescended testes (primary). The ESUR SPI-WG produced this consensus paper in which the existing literature on MRI of the scrotum is reviewed. The recommendations for the optimal imaging technique and clinical indications are presented. (orig.)

  5. MRI of the scrotum. Recommendations of the ESUR Scrotal and Penile Imaging Working Group

    International Nuclear Information System (INIS)

    Tsili, Athina C.; Ntorkou, Alexandra; Bertolotto, Michele; Turgut, Ahmet Tuncay; Dogra, Vikram; Freeman, Simon; Rocher, Laurence; Belfield, Jane; Studniarek, Michal; Derchi, Lorenzo E.; Oyen, Raymond; Ramchandani, Parvati; Secil, Mustafa; Richenberg, Jonathan

    2018-01-01

    The Scrotal and Penile Imaging Working Group (SPI-WG) appointed by the board of the European Society of Urogenital Radiology (ESUR) has produced recommendations for magnetic resonance imaging (MRI) of the scrotum. The SPI-WG searched for original and review articles published before September 2016 using the Pubmed and Medline databases. Keywords used were 'magnetic resonance imaging', 'testis or testicle or testicular', 'scrotum', 'intratesticular', 'paratesticular', 'extratesticular' 'diffusion-weighted', 'dynamic MRI'. Consensus was obtained among the members of the subcommittee. The expert panel proposed recommendations using Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence. The recommended MRI protocol should include T1-, T2-weighted imaging, diffusion-weighted imaging and dynamic contrast-enhanced MRI. Scrotal MRI can be clinically applied for lesion characterisation (primary), including both intratesticular and paratesticular masses, differentiation between germ-cell and non-germ-cell neoplasms (evolving), characterisation of the histological type of testicular germ cell neoplasms (TGCNs, in selected cases), local staging of TGCNs (primary), acute scrotum (in selected cases), trauma (in selected cases) and undescended testes (primary). The ESUR SPI-WG produced this consensus paper in which the existing literature on MRI of the scrotum is reviewed. The recommendations for the optimal imaging technique and clinical indications are presented. (orig.)

  6. MRI and CBCT image registration of temporomandibular joint: a systematic review.

    Science.gov (United States)

    Al-Saleh, Mohammed A Q; Alsufyani, Noura A; Saltaji, Humam; Jaremko, Jacob L; Major, Paul W

    2016-05-10

    The purpose of the present review is to systematically and critically analyze the available literature regarding the importance, applicability, and practicality of (MRI), computerized tomography (CT) or cone-beam CT (CBCT) image registration for TMJ anatomy and assessment. A systematic search of 4 databases; MEDLINE, EMBASE, EBM reviews and Scopus, was conducted by 2 reviewers. An additional manual search of the bibliography was performed. All articles discussing the magnetic resonance imaging MRI and CT or CBCT image registration for temporomandibular joint (TMJ) visualization or assessment were included. Only 3 articles satisfied the inclusion criteria. All included articles were published within the last 7 years. Two articles described MRI to CT multimodality image registration as a complementary tool to visualize TMJ. Both articles used images of one patient only to introduce the complementary concept of MRI-CT fused image. One article assessed the reliability of using MRI-CBCT registration to evaluate the TMJ disc position and osseous pathology for 10 temporomandibular disorder (TMD) patients. There are very limited studies of MRI-CT/CBCT registration to reach a conclusion regarding its accuracy or clinical use in the temporomandibular joints.

  7. Efficacy of dynamic susceptibility contrast MRI using echo-planar imaging in differential diagnosis of breast tumors

    International Nuclear Information System (INIS)

    Yoshino, Ayako

    1998-01-01

    It has been shown that T1-weighted dynamic MR imaging is a useful method in differentiating malignant breast tumors from benign lesions. Invasive breast carcinomas enhance more rapidly than benign lesions such as fibroadenomas, papillomas, and proliferative fibrocystic diseases. However, significant overlap in the dynamic profile of benign and malignant lesions may occur, resulting in relatively low specificity, which is an inherent limitation of this technique. The author attempted to improve diagnostic accuracy by utilizing dynamic susceptibility contrast MR imaging (DSC-MRI) with a single-shot echo-planar imaging sequence. Twenty-two patients underwent DSC-MRI using a 1.5-T unit (Magnetom Vision, Siemens). Images were obtained before, during and after the bolus injection of 20 mL of gadopentetate dimeglumine. The signal reduction rate within the first 30 seconds (ΔRT2) was calculated by the following equation: ΔRT2 = (postcontrast signal intensity-precontrast signal intensity) /precontrast signal intensity. A rapid, strong decrease in signal intensity was observed on the first pass of the contrast material in all cases of carcinoma, whereas no or only a minimal decrease in signal intensity was observed in all but one of the benign lesions. This method seems to be more accurate than T1-weighted dynamic MR imaging in the differentiation benign and malignant breast lesions. Since DSC-MRI can be performed quickly, subsequent conventional T1-weighted imaging can provide additional information about the morphologic features of lesions, to further support the diagnosis. In conclusion, DSC-MRI seems to be a promising method for the accurate preoperative assessment of breast lesions. (author)

  8. Efficacy of dynamic susceptibility contrast MRI using echo-planar imaging in differential diagnosis of breast tumors

    Energy Technology Data Exchange (ETDEWEB)

    Yoshino, Ayako [Kyorin Univ., Mitaka, Tokyo (Japan). School of Medicine

    1998-07-01

    It has been shown that T1-weighted dynamic MR imaging is a useful method in differentiating malignant breast tumors from benign lesions. Invasive breast carcinomas enhance more rapidly than benign lesions such as fibroadenomas, papillomas, and proliferative fibrocystic diseases. However, significant overlap in the dynamic profile of benign and malignant lesions may occur, resulting in relatively low specificity, which is an inherent limitation of this technique. The author attempted to improve diagnostic accuracy by utilizing dynamic susceptibility contrast MR imaging (DSC-MRI) with a single-shot echo-planar imaging sequence. Twenty-two patients underwent DSC-MRI using a 1.5-T unit (Magnetom Vision, Siemens). Images were obtained before, during and after the bolus injection of 20 mL of gadopentetate dimeglumine. The signal reduction rate within the first 30 seconds ({Delta}RT2) was calculated by the following equation: {Delta}RT2 (postcontrast signal intensity-precontrast signal intensity) /precontrast signal intensity. A rapid, strong decrease in signal intensity was observed on the first pass of the contrast material in all cases of carcinoma, whereas no or only a minimal decrease in signal intensity was observed in all but one of the benign lesions. This method seems to be more accurate than T1-weighted dynamic MR imaging in the differentiation benign and malignant breast lesions. Since DSC-MRI can be performed quickly, subsequent conventional T1-weighted imaging can provide additional information about the morphologic features of lesions, to further support the diagnosis. In conclusion, DSC-MRI seems to be a promising method for the accurate preoperative assessment of breast lesions. (author)

  9. Facilitating tumor functional assessment by spatially relating 3D tumor histology and In Vivo MRI: Image registration approach

    NARCIS (Netherlands)

    L. Alic (Lejla); J.C. Haeck (Joost); K. Bol (Karin); S. Klein (Stefan); S.T. van Tiel (Sandra); P.A. Wielepolski (Piotr); M. de Jong (Marion); W.J. Niessen (Wiro); M.R. Bernsen (Monique); J.F. Veenland (Jifke)

    2011-01-01

    textabstractBackground: Magnetic resonance imaging (MRI), together with histology, is widely used to diagnose and to monitor treatment in oncology. Spatial correspondence between these modalities provides information about the ability of MRI to characterize cancerous tissue. However, registration is

  10. Facilitating tumor functional assessment by spatially relating 3D tumor histology and in vivo MRI : Image registration approach

    NARCIS (Netherlands)

    Alic, L.; Haeck, J.C.; Bol, K.; Klein, S.; Van Tiel, S.T.; Wielepolski, P.A.; De Jong, M.; Niessen, W.J.; Bernsen, M.; Veenland, J.F.

    2011-01-01

    Background Magnetic resonance imaging (MRI), together with histology, is widely used to diagnose and to monitor treatment in oncology. Spatial correspondence between these modalities provides information about the ability of MRI to characterize cancerous tissue. However, registration is complicated

  11. Facilitating tumor functional assessment by spatially relating 3D tumor histology and in vivo MRI: Image registration approach

    NARCIS (Netherlands)

    Alić, L.; Haeck, J.C.; Bol, K.; Klein, S.; Tiel, S.T. van; Wielopolski, P.A.; Bijster, M.; Bernsen, M.; Jong, M. de; Niessen, W.J.; Veenland, J.F.

    2011-01-01

    Background: Magnetic resonance imaging (MRI), together with histology, is widely used to diagnose and to monitor treatment in oncology. Spatial correspondence between these modalities provides information about the ability of MRI to characterize cancerous tissue. However, registration is complicated

  12. A single-mode data acquisition architecture for PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Sportelli, Giancarlo; Belcari, Nicola; Bisogni, Maria Giuseppina; Camarlinghi, Niccolo; Zaccaro, Emanuele; Del Guerra, Alberto [Department of Physics, University of Pisa and INFN, Pisa (Italy)

    2015-05-18

    The development of MRI compatible detectors based on compact solid state photomultipliers has recently led to simultaneous fully integrated PET/MRI systems for human imaging. The PET acquisition design for MRI integration is known to have several additional constraints, including smaller space, electromagnetic compatibility issues and thermal management. The current work presents the PET acquisition architecture that has been developed for the TRIMAGE project, whose aim is to provide a cost effective, commercial grade trimodality PET/MRI/EEG scanner. The TRIMAGE PET component consists of 216 modules of 2.5 cm x 2.5 cm, arranged in 18 rectangular detectors of 5 cm x 15 cm, the latter in the axial direction, to form a full ring of 31 cm diameter. Each module consists of a staggered dual layer LYSO matrix read out by two arrays of 4 x 8 SiPMs and an ASIC. The detector board hosts a low-power low-end FPGA that performs pixel identification, energy calibration and handles the communication between the ASICs and the motherboard, which is located in proximity of the scanner. Data is streamed using high-density shielded cables and high-speed LVDS transmission to 9 low-end SoC FPGAs and from there to a central mainboard where coincidences and events statistics are processed. Coincidence data is finally transmitted to a host PC for image reconstruction. The proposed architecture and technological solutions will be presented and discussed.

  13. A single-mode data acquisition architecture for PET/MRI

    International Nuclear Information System (INIS)

    Sportelli, Giancarlo; Belcari, Nicola; Bisogni, Maria Giuseppina; Camarlinghi, Niccolo; Zaccaro, Emanuele; Del Guerra, Alberto

    2015-01-01

    The development of MRI compatible detectors based on compact solid state photomultipliers has recently led to simultaneous fully integrated PET/MRI systems for human imaging. The PET acquisition design for MRI integration is known to have several additional constraints, including smaller space, electromagnetic compatibility issues and thermal management. The current work presents the PET acquisition architecture that has been developed for the TRIMAGE project, whose aim is to provide a cost effective, commercial grade trimodality PET/MRI/EEG scanner. The TRIMAGE PET component consists of 216 modules of 2.5 cm x 2.5 cm, arranged in 18 rectangular detectors of 5 cm x 15 cm, the latter in the axial direction, to form a full ring of 31 cm diameter. Each module consists of a staggered dual layer LYSO matrix read out by two arrays of 4 x 8 SiPMs and an ASIC. The detector board hosts a low-power low-end FPGA that performs pixel identification, energy calibration and handles the communication between the ASICs and the motherboard, which is located in proximity of the scanner. Data is streamed using high-density shielded cables and high-speed LVDS transmission to 9 low-end SoC FPGAs and from there to a central mainboard where coincidences and events statistics are processed. Coincidence data is finally transmitted to a host PC for image reconstruction. The proposed architecture and technological solutions will be presented and discussed.

  14. How does MRI work? An introduction into physics and functionality of magnetic resonance imaging. 6. ed.

    International Nuclear Information System (INIS)

    Weishaupt, Dominik; Marincek, Borut

    2009-01-01

    The book provides the basic physics and describes the functionality of magnetic resonance tomography in a very illustrative way. The following topics are covered: Spins and the magnetic resonance phenomenon, image contrast, three-dimensional structure, signal-to-noise ratio, description of a magnetic resonance tomography, basic pulse sequences, fast pulse sequences, methods for fat suppression, parallel imaging, cardiovascular imaging, MR contrast media, MR image artifacts, high-field MRI, imaging beyond morphology and structure, safety and risks [de

  15. Signal to noise comparison of metabolic imaging methods on a clinical 3T MRI

    DEFF Research Database (Denmark)

    Müller, C. A.; Hansen, Rie Beck; Skinner, J. G.

    MRI with hyperpolarized tracers has enabled new diagnostic applications, e.g. metabolic imaging in cancer research. However, the acquisition of the transient, hyperpolarized signal with spatial and frequency resolution requires dedicated imaging methods. Here, we compare three promising candidate...... for 2D MR spectroscopic imaging (MRSI): (i) multi-echo balanced steady-state free precession (me-bSSFP), 1,2 (ii) echo planar spectroscopic imaging (EPSI) sequence and (iii) phase-encoded, pulseacquisition chemical-shift imaging (CSI)...

  16. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    International Nuclear Information System (INIS)

    Solis, S E; Rodriguez, A O; Wang, R; Tomasi, D

    2011-01-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  17. A multi-slot surface coil for MRI of dual-rat imaging at 4 T

    Energy Technology Data Exchange (ETDEWEB)

    Solis, S E; Rodriguez, A O [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico); Wang, R; Tomasi, D, E-mail: arog@xanum.uam.mx [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2011-06-21

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  18. A multi-slot surface coil for MRI of dual-rat imaging at 4T

    Energy Technology Data Exchange (ETDEWEB)

    Solis, S.E.; Tomasi, D.; Solis, S.E.; Wang, R.; Tomasi, D.; Rodriguez, A.O.

    2011-07-01

    A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

  19. Measurement of Murine Single-Kidney Glomerular Filtration Rate Using Dynamic Contrast-Enhanced MRI.

    Science.gov (United States)

    Jiang, Kai; Tang, Hui; Mishra, Prasanna K; Macura, Slobodan I; Lerman, Lilach O

    2018-06-01

    To develop and validate a method for measuring murine single-kidney glomerular filtration rate (GFR) using dynamic contrast-enhanced MRI (DCE-MRI). This prospective study was approved by the Institutional Animal Care and Use Committee. A fast longitudinal relaxation time (T 1 ) measurement method was implemented to capture gadolinium dynamics (1 s/scan), and a modified two-compartment model was developed to quantify GFR as well as renal perfusion using 16.4T MRI in mice 2 weeks after unilateral renal artery stenosis (RAS, n = 6) or sham (n = 8) surgeries. This approach was validated by comparing model-derived GFR and perfusion to those obtained by fluorescein isothiocyanante (FITC)-inulin clearance and arterial spin labeling (ASL), respectively, using the Pearson's and Spearman's rank correlations and Bland-Altman analysis. The compartmental model provided a good fitting to measured gadolinium dynamics in both normal and RAS kidneys. The proposed DCE-MRI method offered assessment of single-kidney GFR and perfusion, comparable to the FITC-inulin clearance (Pearson's correlation coefficient r = 0.95 and Spearman's correlation coefficient ρ = 0.94, P < 0.0001, and mean difference -7.0 ± 11.0 μL/min) and ASL (r = 0.92 and ρ = 0.84, P < 0.0001, and mean difference 4.4 ± 66.1 mL/100 g/min) methods. The proposed DCE-MRI method may be useful for reliable noninvasive measurements of single-kidney GFR and perfusion in mice. Magn Reson Med 79:2935-2943, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  20. MRI, geometric distortion of the image and stereotaxy

    International Nuclear Information System (INIS)

    Derosier, C.; Delegue, G.; Munier, T.; Pharaboz, C.; Cosnard, G.

    1991-01-01

    The MRI technology may be the starting-point of geometric distortion. The mathematical preciseness of a spatial location may be disturbed and alter the guidance of a MRI interventional act, especially in stereotactic brain biopsy. A review of the literature shows errors of 1 to 1.5 mm. Our results show an error of 0.16±0.66. The control of quality: homogeneity and calibration of magnetic-field gradients, permit an improve of the ballistic preciseness and give permission to realize the guidance of a stereotactic brain biopsy with the alone MRI

  1. In vivo tomographic imaging with fluorescence and MRI using tumor-targeted dual-labeled nanoparticles

    Directory of Open Access Journals (Sweden)

    Zhang Y

    2013-12-01

    Full Text Available Yue Zhang,1 Bin Zhang,1 Fei Liu,1,2 Jianwen Luo,1,3 Jing Bai1 1Department of Biomedical Engineering, School of Medicine, 2Tsinghua-Peking Center for Life Sciences, 3Center for Biomedical Imaging Research, Tsinghua University, Beijing, People's Republic of China Abstract: Dual-modality imaging combines the complementary advantages of different modalities, and offers the prospect of improved preclinical research. The combination of fluorescence imaging and magnetic resonance imaging (MRI provides cross-validated information and direct comparison between these modalities. Here, we report on the application of a novel tumor-targeted, dual-labeled nanoparticle (NP, utilizing iron oxide as the MRI contrast agent and near infrared (NIR dye Cy5.5 as the fluorescent agent. Results of in vitro experiments verified the specificity of the NP to tumor cells. In vivo tumor targeting and uptake of the NPs in a mouse model were visualized by fluorescence and MR imaging collected at different time points. Quantitative analysis was carried out to evaluate the efficacy of MRI contrast enhancement. Furthermore, tomographic images were also acquired using both imaging modalities and cross-validated information of tumor location and size between these two modalities was revealed. The results demonstrate that the use of dual-labeled NPs can facilitate the dual-modal detection of tumors, information cross-validation, and direct comparison by combing fluorescence molecular tomography (FMT and MRI. Keywords: dual-modality, fluorescence molecular tomography (FMT, magnetic resonance imaging (MRI, nanoparticle

  2. Single-Shot MR Spectroscopic Imaging with Partial Parallel Imaging

    Science.gov (United States)

    Posse, Stefan; Otazo, Ricardo; Tsai, Shang-Yueh; Yoshimoto, Akio Ernesto; Lin, Fa-Hsuan

    2010-01-01

    An MR spectroscopic imaging (MRSI) pulse sequence based on Proton-Echo-Planar-Spectroscopic-Imaging (PEPSI) is introduced that measures 2-dimensional metabolite maps in a single excitation. Echo-planar spatial-spectral encoding was combined with interleaved phase encoding and parallel imaging using SENSE to reconstruct absorption mode spectra. The symmetrical k-space trajectory compensates phase errors due to convolution of spatial and spectral encoding. Single-shot MRSI at short TE was evaluated in phantoms and in vivo on a 3 T whole body scanner equipped with 12-channel array coil. Four-step interleaved phase encoding and 4-fold SENSE acceleration were used to encode a 16×16 spatial matrix with 390 Hz spectral width. Comparison with conventional PEPSI and PEPSI with 4-fold SENSE acceleration demonstrated comparable sensitivity per unit time when taking into account g-factor related noise increases and differences in sampling efficiency. LCModel fitting enabled quantification of Inositol, Choline, Creatine and NAA in vivo with concentration values in the ranges measured with conventional PEPSI and SENSE-accelerated PEPSI. Cramer-Rao lower bounds were comparable to those obtained with conventional SENSE-accelerated PEPSI at the same voxel size and measurement time. This single-shot MRSI method is therefore suitable for applications that require high temporal resolution to monitor temporal dynamics or to reduce sensitivity to tissue movement. PMID:19097245

  3. Analysis of spatial and temporal dynamics of xylem refilling in Acer rubrum L. using magnetic resonance imaging (MRI.

    Directory of Open Access Journals (Sweden)

    Maciej Andrzej Zwieniecki

    2013-07-01

    Full Text Available We report results of an analysis of embolism formation and subsequent refilling observed in stems of Acer rubrum L. using magnetic resonance imaging (MRI. MRI is one of the very few techniques that can provide direct non-destructive observations of the water content within opaque biological materials at a micrometer resolution. Thus, it has been used to determine temporal dynamics and water distributions within xylem tissue. In this study, we found good agreement between MRI measures of pixel brightness to assess xylem liquid water content and the percent loss in hydraulic conductivity (PLC in response to water stress (P50 values of 2.51 and 2.70 for MRI and PLC, respectively. These data provide strong support that pixel brightness is well correlated to PLC and can be used as a proxy of PLC even when single vessels cannot be resolved on the image. Pressure induced embolism in moderately stressed plants resulted in initial drop of pixel brightness. This drop was followed by brightness gain over 100 minutes following pressure application suggesting that plants can restore water content in stem after induced embolism. This recovery was limited only to current year wood ring; older wood did not show signs of recovery within the length of experiment (16 hours. In vivo MRI observations of the xylem of moderately stressed (~-0.5 MPa A. rubrum stems revealed evidence of a spontaneous embolism formation followed by rapid refilling (~30 minutes. Spontaneous (not induced embolism formation was observed only once, despite over 60 hours of continuous MRI observations made on several plants. Thus this observation provide evidence for presence of naturally occurring embolism-refilling cycle in A. rubrum, but it is impossible to infer any conclusions in relation to its frequency in nature.

  4. Neurite density imaging versus imaging of microscopic anisotropy in diffusion MRI: A model comparison using spherical tensor encoding.

    Science.gov (United States)

    Lampinen, Björn; Szczepankiewicz, Filip; Mårtensson, Johan; van Westen, Danielle; Sundgren, Pia C; Nilsson, Markus

    2017-02-15

    In diffusion MRI (dMRI), microscopic diffusion anisotropy can be obscured by orientation dispersion. Separation of these properties is of high importance, since it could allow dMRI to non-invasively probe elongated structures such as neurites (axons and dendrites). However, conventional dMRI, based on single diffusion encoding (SDE), entangles microscopic anisotropy and orientation dispersion with intra-voxel variance in isotropic diffusivity. SDE-based methods for estimating microscopic anisotropy, such as the neurite orientation dispersion and density imaging (NODDI) method, must thus rely on model assumptions to disentangle these features. An alternative approach is to directly quantify microscopic anisotropy by the use of variable shape of the b-tensor. Along those lines, we here present the 'constrained diffusional variance decomposition' (CODIVIDE) method, which jointly analyzes data acquired with diffusion encoding applied in a single direction at a time (linear tensor encoding, LTE) and in all directions (spherical tensor encoding, STE). We then contrast the two approaches by comparing neurite density estimated using NODDI with microscopic anisotropy estimated using CODIVIDE. Data were acquired in healthy volunteers and in glioma patients. NODDI and CODIVIDE differed the most in gray matter and in gliomas, where NODDI detected a neurite fraction higher than expected from the level of microscopic diffusion anisotropy found with CODIVIDE. The discrepancies could be explained by the NODDI tortuosity assumption, which enforces a connection between the neurite density and the mean diffusivity of tissue. Our results suggest that this assumption is invalid, which leads to a NODDI neurite density that is inconsistent between LTE and STE data. Using simulations, we demonstrate that the NODDI assumptions result in parameter bias that precludes the use of NODDI to map neurite density. With CODIVIDE, we found high levels of microscopic anisotropy in white matter

  5. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  6. Utility of reconstructed image from 3-D MRI in the region of oral cavity

    International Nuclear Information System (INIS)

    Murakami, Shumei; Kakimoto, Naoya; Nakatani, Atsutoshi; Furuya, Shigeo; Furukawa, Shouhei; Fuchihata, Hajime

    1998-01-01

    The 3-D MRI with short TR was performed in the region of oral cavity, jaw and face, and utility of the reconstructed image was examined. Subjects were 8 healthy volunteers and 12 patients. The 3-D MRI was performed using SPGR with the following parameters; TR: 8 or 9 msec, TE: 2 or 3 msec, and FA: 20-30 degrees. Imaging direction was vertical to body axis. The matrix number was 256 x 192, slice thickness was 1 mm, slice interval was 0 and slice number was 128. The obtained image was reconstructed using software Reformat''. Detectability of temporomandibular joint disc was not enough in 8 of 20 cases. Detectability of mandibular canal was clear in 18 of 20 cases. In panorama MRI, soft tissue such as submandibular gland was detected. But, in hard tissue such as teeth or maxilla, there was a more little information in panorama MRI than in panorama X-ray photography. (K.H.)

  7. Imaging technique and current status of valvular heart disease using cardiac MRI

    International Nuclear Information System (INIS)

    Lotz, J.; Sohns, J.M.

    2013-01-01

    The main indications for cardiac magnetic resonance imaging (MRI) in the evaluation of valvular heart disease are pathologies of the aortic and pulmonary valve. For mitral and tricuspid valve pathologies MRI is not the first line modality as these are usually well visualized by echocardiography. The advantages of MRI in valvular heart disease are a high reliability in the evaluation of ventricular volumes and function as well as the assessment of the perivalvular arterial or atrial structures. This reliability and the limitless access to any imaging plane partially compensates for the lower temporal and spatial resolution in comparison to echocardiography. In patients with congenital heart disease, cardiac MRI is established as a valuable diagnostic tool in daily clinical management, especially for the evaluation of pulmonary valve defects. Nevertheless, echocardiography remains the first-line diagnostic imaging tool for the foreseeable future. (orig.) [de

  8. Single photon imaging. New instrumentation and techniques

    International Nuclear Information System (INIS)

    Muehllehner, G.; Colsher, J.

    1981-01-01

    The performance of Anger scintillation cameras continues to be enhanced through a series of small improvements which result in significantly better imaging characteristics. The most recent changes in camera design consist of: (1) the introduction of photomultipliers with better photocathode and electron collection efficiencies, (2) the use of thinner (3/8 or 1/4 in) crystals giving slightly better intrinsic resolution for low gamma-ray energies, (3) inclusion of a spatially varying energy window to compensate for variations of light collection efficiency, (4) event-by-event, real-time distortion removal for uniformity correction, and (5) introduction of new methods to improve the count-rate capability. Whereas some of these improvements are due to better understanding of the fundamentals of camera design, others are the result of technological advances in electronic components such as analogue-to-digital converters, microprocessors and high-density digital memories. The development of single photon tomography has developed along two parallel paths. Multipinhole and rotating slant-hole collimator attachments provide some degree of longitudinal tomography, and are currently being applied to cardiac imaging. At the same time rotating camera systems capable of transverse as well as longitudinal imaging are being refined technically and evaluated clinically. Longitudinal tomography is of limited use in quantitative studies and is likely to be an interim solution to three-dimensional imaging. Rotating camera systems, on the other hand, not only provide equal resolution in all three dimensions but are also capable of providing quantitative accuracy. This is the result of progress in attenuation correction and the design of special collimators. Single photon tomography provides a small but noticeable improvement in diagnostic accuracy which is likely to result in widespread use of rotating camera systems in the future

  9. Cortical activities of single-trial P300 amplitudes modulated by memory load using simultaneous EEG-fMRI

    Science.gov (United States)

    Zhang, Qiushi; Zhao, Xiaojie; Zhu, Chaozhe; Yang, Xueqian; Yao, Li

    2015-03-01

    The functional magnetic resonance imaging (fMRI) researches on working memory have found that activation of cortical areas appeared dependent on memory load, and event-related potentials (ERP) studies have demonstrated that amplitudes of P300 decreased significantly when working memory load increased. However, the cortical activities related with P300 amplitudes under different memory loads remains unclear. Joint fMRI and EEG analysis which fusions the time and spatial information in simultaneous EEG-fMRI recording can reveal the regional activation at each ERP time point. In this paper, we first used wavelet transform to obtain the single-trial amplitudes of P300 caused by a digital N-back task in the simultaneous EEG-fMRI recording as the ERP feature sequences. Then the feature sequences in 1-back condition and 3-back condition were introduced into general linear model (GLM) separately as parametric modulations to compare the cortical activation under different memory loads. The results showed that the average amplitudes of P300 in 3-back significantly decreased than that in 1-back, and the activities induced by ERP feature sequences in 3-back also significantly decreased than that in the 1-back, including the insular, anterior cingulate cortex, right inferior frontal gyrus, and medial frontal gyrus, which were relevant to the storage, monitoring, and manipulation of information in working memory task. Moreover, the difference in the activation caused by ERP feature showed a positive correlation with the difference in behavioral performance. These findings demonstrated the locations of P300 amplitudes differences modulated by the memory load and its relationship with the behavioral performance.

  10. First image from a combined positron emission tomography and field-cycled MRI system.

    Science.gov (United States)

    Bindseil, Geron A; Gilbert, Kyle M; Scholl, Timothy J; Handler, William B; Chronik, Blaine A

    2011-07-01

    Combining positron emission tomography and MRI modalities typically requires using either conventional MRI with a MR-compatible positron emission tomography system or a modified MR system with conventional positron emission tomography. A feature of field-cycled MRI is that all magnetic fields can be turned off rapidly, enabling the use of conventional positron emission tomography detectors based on photomultiplier tubes. In this demonstration, two photomultiplier tube-based positron emission tomography detectors were integrated with a field-cycled MRI system (0.3 T/4 MHz) by placing them into a 9-cm axial gap. A positron emission tomography-MRI phantom consisting of a triangular arrangement of positron-emitting point sources embedded in an onion was imaged in a repeating interleaved sequence of ∼1 sec MRI then 1 sec positron emission tomography. The first multimodality images from the combined positron emission tomography and field-cycled MRI system show no additional artifacts due to interaction between the systems and demonstrate the potential of this approach to combining positron emission tomography and MRI. Copyright © 2010 Wiley-Liss, Inc.

  11. An iterative reconstruction method of complex images using expectation maximization for radial parallel MRI

    International Nuclear Information System (INIS)

    Choi, Joonsung; Kim, Dongchan; Oh, Changhyun; Han, Yeji; Park, HyunWook

    2013-01-01

    In MRI (magnetic resonance imaging), signal sampling along a radial k-space trajectory is preferred in certain applications due to its distinct advantages such as robustness to motion, and the radial sampling can be beneficial for reconstruction algorithms such as parallel MRI (pMRI) due to the incoherency. For radial MRI, the image is usually reconstructed from projection data using analytic methods such as filtered back-projection or Fourier reconstruction after gridding. However, the quality of the reconstructed image from these analytic methods can be degraded when the number of acquired projection views is insufficient. In this paper, we propose a novel reconstruction method based on the expectation maximization (EM) method, where the EM algorithm is remodeled for MRI so that complex images can be reconstructed. Then, to optimize the proposed method for radial pMRI, a reconstruction method that uses coil sensitivity information of multichannel RF coils is formulated. Experiment results from synthetic and in vivo data show that the proposed method introduces better reconstructed images than the analytic methods, even from highly subsampled data, and provides monotonic convergence properties compared to the conjugate gradient based reconstruction method. (paper)

  12. Free Radical Imaging Using In Vivo Dynamic Nuclear Polarization-MRI.

    Science.gov (United States)

    Utsumi, Hideo; Hyodo, Fuminori

    2015-01-01

    Redox reactions that generate free radical intermediates are essential to metabolic processes, and their intermediates can produce reactive oxygen species, which may promote diseases related to oxidative stress. The development of an in vivo electron spin resonance (ESR) spectrometer and its imaging enables us noninvasive and direct measurement of in vivo free radical reactions in living organisms. The dynamic nuclear polarization magnetic resonance imaging (DNP-MRI), also called PEDRI or OMRI, is also a new imaging method for observing free radical species in vivo. The spatiotemporal resolution of free radical imaging with DNP-MRI is comparable with that in MRI, and each of the radical species can be distinguished in the spectroscopic images by changing the frequency or magnetic field of ESR irradiation. Several kinds of stable nitroxyl radicals were used as spin probes to detect in vivo redox reactions. The signal decay of nitroxyl probes, which is determined with in vivo DNP-MRI, reflects the redox status under oxidative stress, and the signal decay is suppressed by prior administration of antioxidants. In addition, DNP-MRI can also visualize various intermediate free radicals from the intrinsic redox molecules. This noninvasive method, in vivo DNP-MRI, could become a useful tool for investigating the mechanism of oxidative injuries in animal disease models and the in vivo effects of antioxidant drugs. © 2015 Elsevier Inc. All rights reserved.

  13. Diagnostic imaging strategy for MDCT- or MRI-detected breast lesions: use of targeted sonography

    International Nuclear Information System (INIS)

    Nakano, Satoko; Ohtsuka, Masahiko; Mibu, Akemi; Karikomi, Masato; Sakata, Hitomi; Yamamoto, Masahiro

    2012-01-01

    Leading-edge technology such as magnetic resonance imaging (MRI) or computed tomography (CT) often reveals mammographically and ultrasonographically occult lesions. MRI is a well-documented, effective tool to evaluate these lesions; however, the detection rate of targeted sonography varies for MRI detected lesions, and its significance is not well established in diagnostic strategy of MRI detected lesions. We assessed the utility of targeted sonography for multidetector-row CT (MDCT)- or MRI-detected lesions in practice. We retrospectively reviewed 695 patients with newly diagnosed breast cancer who were candidates for breast conserving surgery and underwent MDCT or MRI in our hospital between January 2004 and March 2011. Targeted sonography was performed in all MDCT- or MRI-detected lesions followed by imaging-guided biopsy. Patient background, histopathology features and the sizes of the lesions were compared among benign, malignant and follow-up groups. Of the 695 patients, 61 lesions in 56 patients were detected by MDCT or MRI. The MDCT- or MRI-detected lesions were identified by targeted sonography in 58 out of 61 lesions (95.1%). Patients with pathological diagnoses were significantly older and more likely to be postmenopausal than the follow-up patients. Pathological diagnosis proved to be benign in 20 cases and malignant in 25. The remaining 16 lesions have been followed up. Lesion size and shape were not significantly different among the benign, malignant and follow-up groups. Approximately 95% of MDCT- or MRI-detected lesions were identified by targeted sonography, and nearly half of these lesions were pathologically proven malignancies in this study. Targeted sonography is a useful modality for MDCT- or MRI-detected breast lesions

  14. Single-task fMRI overlap predicts concurrent multitasking interference.

    Science.gov (United States)

    Nijboer, Menno; Borst, Jelmer; van Rijn, Hedderik; Taatgen, Niels

    2014-10-15

    There is no consensus regarding the origin of behavioral interference that occurs during concurrent multitasking. Some evidence points toward a multitasking locus in the brain, while other results imply that interference is the consequence of task interactions in several brain regions. To investigate this issue, we conducted a functional MRI (fMRI) study consisting of three component tasks, which were performed both separately and in combination. The results indicated that no specific multitasking area exists. Instead, different patterns of activation across conditions could be explained by assuming that the interference is a result of task interactions. Additionally, similarity in single-task activation patterns correlated with a decrease in accuracy during dual-task conditions. Taken together, these results support the view that multitasking interference is not due to a bottleneck in a single "multitasking" brain region, but is a result of interactions between concurrently running processes. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Understanding Patient Preference in Female Pelvic Imaging: Transvaginal Ultrasound and MRI.

    Science.gov (United States)

    Sakala, Michelle D; Carlos, Ruth C; Mendiratta-Lala, Mishal; Quint, Elisabeth H; Maturen, Katherine E

    2018-04-01

    Women with pelvic pain or abnormal uterine bleeding may undergo diagnostic imaging. This study evaluates patient experience in transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI) and explores correlations between preference and symptom severity. Institutional review board approval was obtained for this Health Insurance Portability and Accountability Act-compliant prospective study. Fifty premenopausal women with pelvic symptoms evaluated by recent TVUS and MRI and without history of gynecologic cancer or hysterectomy were included. A phone questionnaire used validated survey instruments including Uterine Fibroid Symptoms Quality of Life index, Testing Morbidities Index, and Wait Trade Off for TVUS and MRI examinations. Using Wait Trade Off, patients preferred TVUS over MRI (3.58 vs 2.80 weeks, 95% confidence interval [CI] -1.63, 0.12; P = .08). Summary test utility of Testing Morbidities Index for MRI was worse than for TVUS (81.64 vs 87.42, 95%CI 0.41, 11.15; P = .03). Patients reported greater embarrassment during TVUS than during MRI (P MRI, and greater mental (P = .02) and physical (P = .02) problems after MRI versus TVUS. Subscale correlations showed physically inactive women rated TVUS more negatively (R = -0.32, P = .03), whereas women with more severe symptoms of loss of control of health (R = -0.28, P = .04) and sexual dysfunction (R = -0.30, P = .03) rated MRI more negatively. Women with pelvic symptoms had a slight but significant preference for TVUS over MRI. Identifying specific distressing aspects of each test and patient factors contributing to negative perceptions can direct improvement in both test environment and patient preparation. Improved patient experience may increase imaging value. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  16. Atlas-guided generation of pseudo-CT images for MRI-only and hybrid PET-MRI-guided radiotherapy treatment planning

    DEFF Research Database (Denmark)

    Arabi, H.; Koutsouvelis, N.; Rouzaud, M.

    2016-01-01

    Magnetic resonance imaging (MRI)-guided attenuation correction (AC) of positron emission tomography (PET) data and/or radiation therapy (RT) treatment planning is challenged by the lack of a direct link between MRI voxel intensities and electron density. Therefore, even if this is not a trivial t......-CT images from conventional Dixon MRI sequences with improved bone extraction accuracy. The approach is promising for potential use in PET AC and MRI-only or hybrid PET/MRI-guided RT treatment planning. © 2016 Institute of Physics and Engineering in Medicine.......Magnetic resonance imaging (MRI)-guided attenuation correction (AC) of positron emission tomography (PET) data and/or radiation therapy (RT) treatment planning is challenged by the lack of a direct link between MRI voxel intensities and electron density. Therefore, even if this is not a trivial...... the conventional MRI segmentation technique and a recently proposed multi-atlas approach. The clinical studies consisted of pelvic CT, PET and MRI scans of 12 patients with loco-regionally advanced rectal disease. In the first step, bone segmentation of the target image is optimized through local weighted atlas...

  17. Primary ureteral carcinoma: MRI diagnosis and comparison with other diagnostic imaging facilities

    International Nuclear Information System (INIS)

    An Ningyu; Jiang Bo; Cai Youquan; Liang Yan

    2004-01-01

    Objective: To investigate MRI examination methods and imaging manifestations of primary ureteral carcinoma, and to evaluate its clinical values when comparing with other diagnostic imaging facilities. Methods: Eighty-seven cases of primary ureteral carcinoma who were operated within recent 8 years came into the study, among which, 35 cases had MRI examinations. For MRI examination, coronal heavy T 2 WI (water imaging) was performed to show the dilated ureter, then axial T 2 WI and T 1 WI were scanned at the obstruction level. 11 cases underwent additional Gd-DTPA dynamic contrast enhanced scans. The original pre-operative diagnostic reports of various imaging facilities were analyzed comparing with the results of operation and pathology. Results: MRI showed ureteral dilatation in 33 of 35 cases, no abnormal appearance in 1 case, and only primary kidney atrophy post renal transplantation in 1 case. Among the 33 cases with ureteral obstruction, soft mass at the obstruction level was detected on axial scans in 32 cases. The lesions showed gradual and homogeneous mild to moderate enhancement on contrast MRI. The overall employment rate of imaging facilities was as follows: ultrasound (94.3%), IVU (59.8%), CT (52.9%), MRI (40.2%), and RUP (35.6%). The accurate diagnostic rate was as follows :MRI (91.4%), RUP (80.6%), CT (63.0%), ultrasound (47.6%), and IVU (11.5%). Conclusion: Combination of MR water imaging and conventional sequences can demonstrate most primary ureteral carcinoma lesions and has a highest diagnostic accuracy among the current diagnostic imaging facilities. It should be taken as the first diagnostic imaging method of choice when primary ureteral carcinoma is suspected after ultrasound screening

  18. Application of magnetic resonance imaging (MRI) technique on monitoring flower bud differentiation of tulip

    International Nuclear Information System (INIS)

    Han Haojun; Yang Hongguang; Han Hongbin; Sun Xiaomei

    2009-01-01

    Magnetic resonance imaging (MRI) was used for observing morphogenesis process in the living specimen situation of tulip flower buds. Through a comparison of different MRI imaging formation technique (longitudinal relaxation-T1WI, transverse relaxation time weighted imaging-T2WI, proton density weighted imaging-PDWI), seeking for an accurate and practical MRI technique to observe tulip bulb and differentiation period of flower bud. The results showed that in the demonstration of the morphological characters as well as morphogenesis process of flower bud differentiation, the T1WI was completely consistent with the results of rough slice, PDWI and T1WI also had obviously higher map quality than the T2WI (P<0.05). It is indicated that the magnetic resonance imaging technique could monitor the development of flower bud differentiation in vivo. (authors)

  19. Fast single image dehazing based on image fusion

    Science.gov (United States)

    Liu, Haibo; Yang, Jie; Wu, Zhengping; Zhang, Qingnian

    2015-01-01

    Images captured in foggy weather conditions often fade the colors and reduce the contrast of the observed objects. An efficient image fusion method is proposed to remove haze from a single input image. First, the initial medium transmission is estimated based on the dark channel prior. Second, the method adopts an assumption that the degradation level affected by haze of each region is the same, which is similar to the Retinex theory, and uses a simple Gaussian filter to get the coarse medium transmission. Then, pixel-level fusion is achieved between the initial medium transmission and coarse medium transmission. The proposed method can recover a high-quality haze-free image based on the physical model, and the complexity of the proposed method is only a linear function of the number of input image pixels. Experimental results demonstrate that the proposed method can allow a very fast implementation and achieve better restoration for visibility and color fidelity compared to some state-of-the-art methods.

  20. Real-time functional MR imaging (fMRI) for presurgical evaluation of paediatric epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Kesavadas, Chandrasekharan; Thomas, Bejoy; Kumar Gupta, Arun [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Imaging Sciences and Interventional Radiology, Trivandrum (India); Sujesh, Sreedharan [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Biomedical Technology Wing, Trivandrum (India); Ashalata, Radhakrishnan; Radhakrishnan, Kurupath [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Neurology, Trivandrum (India); Abraham, Mathew [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Department of Neurosurgery, Trivandrum (India)

    2007-10-15

    The role of fMRI in the presurgical evaluation of children with intractable epilepsy is being increasingly recognized. Real-time fMRI allows the clinician to visualize functional brain activation in real time. Since there is no off-line data analysis as in conventional fMRI, the overall time for the procedure is reduced, making it clinically feasible in a busy clinical sitting. (1) To study the accuracy of real-time fMRI in comparison to conventional fMRI with off-line processing; (2) to determine its effectiveness in mapping the eloquent cortex and language lateralization in comparison to invasive procedures such as intraoperative cortical stimulation and Wada testing; and (3) to evaluate the role of fMRI in presurgical decision making in children with epilepsy. A total of 23 patients (age range 6-18 years) underwent fMRI with sensorimotor, visual and language paradigms. Data processing was done in real time using in-line BOLD. The results of real-time fMRI matched those of off-line processing done using the well-accepted standard technique of statistical parametric mapping (SPM) in all the initial ten patients in whom the two techniques were compared. Coregistration of the fMRI data on a 3-D FLAIR sequence rather than a T1-weighted image gave better information regarding the relationship of the lesion to the area of activation. The results of intraoperative cortical stimulation and fMRI matched in six out of six patients, while the Wada test and fMRI had similar results in four out of five patients in whom these techniques were performed. In the majority of patients in this series the technique influenced patient management. Real-time fMRI is an easily performed and reliable technique in the presurgical workup of children with epilepsy. (orig.)

  1. Real-time functional MR imaging (fMRI) for presurgical evaluation of paediatric epilepsy

    International Nuclear Information System (INIS)

    Kesavadas, Chandrasekharan; Thomas, Bejoy; Kumar Gupta, Arun; Sujesh, Sreedharan; Ashalata, Radhakrishnan; Radhakrishnan, Kurupath; Abraham, Mathew

    2007-01-01

    The role of fMRI in the presurgical evaluation of children with intractable epilepsy is being increasingly recognized. Real-time fMRI allows the clinician to visualize functional brain activation in real time. Since there is no off-line data analysis as in conventional fMRI, the overall time for the procedure is reduced, making it clinically feasible in a busy clinical sitting. (1) To study the accuracy of real-time fMRI in comparison to conventional fMRI with off-line processing; (2) to determine its effectiveness in mapping the eloquent cortex and language lateralization in comparison to invasive procedures such as intraoperative cortical stimulation and Wada testing; and (3) to evaluate the role of fMRI in presurgical decision making in children with epilepsy. A total of 23 patients (age range 6-18 years) underwent fMRI with sensorimotor, visual and language paradigms. Data processing was done in real time using in-line BOLD. The results of real-time fMRI matched those of off-line processing done using the well-accepted standard technique of statistical parametric mapping (SPM) in all the initial ten patients in whom the two techniques were compared. Coregistration of the fMRI data on a 3-D FLAIR sequence rather than a T1-weighted image gave better information regarding the relationship of the lesion to the area of activation. The results of intraoperative cortical stimulation and fMRI matched in six out of six patients, while the Wada test and fMRI had similar results in four out of five patients in whom these techniques were performed. In the majority of patients in this series the technique influenced patient management. Real-time fMRI is an easily performed and reliable technique in the presurgical workup of children with epilepsy. (orig.)

  2. 3D pulmonary perfusion MRI and MR angiography of pulmonary embolism in pigs after a single injection of a blood pool MR contrast agent

    International Nuclear Information System (INIS)

    Fink, Christian; Ley, Sebastian; Puderbach, Michael; Plathow, Christian; Kauczor, Hans-Ulrich; Bock, Michael

    2004-01-01

    The purpose of this study was to assess the feasibility of contrast-enhanced 3D perfusion MRI and MR angiography (MRA) of pulmonary embolism (PE) in pigs using a single injection of the blood pool contrast Gadomer. PE was induced in five domestic pigs by injection of autologous blood thrombi. Contrast-enhanced first-pass 3D perfusion MRI (TE/TR/FA: 1.0 ms/2.2 ms/40 ; voxel size: 1.3 x 2.5 x 4.0 mm 3 ; TA: 1.8 s per data set) and high-resolution 3D MRA (TE/TR/FA: 1.4 ms/3.4 ms/40 ; voxel size: 0.8 x 1.0 x 1.6 mm 3 ) was performed during and after a single injection of 0.1 mmol/kg body weight of Gadomer. Image data were compared to pre-embolism Gd-DTPA-enhanced MRI and post-embolism thin-section multislice CT (n=2). SNR measurements were performed in the pulmonary arteries and lung. One animal died after induction of PE. In all other animals, perfusion MRI and MRA could be acquired after a single injection of Gadomer. At perfusion MRI, PE could be detected by typical wedge-shaped perfusion defects. While the visualization of central PE at MRA correlated well with the CT, peripheral PE were only visualized by CT. Gadomer achieved a higher peak SNR of the lungs compared to Gd-DTPA (21±8 vs. 13±3). Contrast-enhanced 3D perfusion MRI and MRA of PE can be combined using a single injection of the blood pool contrast agent Gadomer. (orig.)

  3. Imaging of tumor viability in lung cancer. Initial results using 23Na-MRI

    International Nuclear Information System (INIS)

    Henzler, T.; Apfaltrer, P.; Haneder, S.; Schoenberg, S.O.; Fink, C.; Konstandin, S.; Schad, L.; Schmid-Bindert, G.; Manegold, C.; Wenz, F.

    2012-01-01

    23 Na-MRI has been proposed as a potential imaging biomarker for the assessment of tumor viability and the evaluation of therapy response but has not yet been evaluated in patients with lung cancer. We aimed to assess the feasibility of 23 Na-MRI in patients with lung cancer. Three patients with stage IV adenocarcinoma of the lung were examined on a clinical 3 Tesla MRI system (Magnetom TimTrio, Siemens Healthcare, Erlangen, Germany). Feasibility of 23 Na-MRI images was proven by comparison and fusion of 23 Na-MRI with 1 H-MR, CT and FDG-PET-CT images. 23 Na signal intensities (SI) of tumor and cerebrospinal fluid (CSF) of the spinal canal were measured and the SI ratio in tumor and CSF was calculated. One chemonaive patient was examined before and after the initiation of combination therapy (Carboplatin, Gemcitabin, Cetuximab). All 23 Na-MRI examinations were successfully completed and were of diagnostic quality. Fusion of 23 Na-MRI images with 1 H-MRI, CT and FDG-PET-CT was feasible in all patients and showed differences in solid and necrotic tumor areas. The mean tumor SI and the tumor/CSF SI ratio were 13.3 ± 1.8 x 103 and 0.83 ± 0.14, respectively. In necrotic tumors, as suggested by central non-FDG-avid areas, the mean tumor SI and the tumor/CSF ratio were 19.4 x 103 and 1.10, respectively. 23 Na-MRI is feasible in patients with lung cancer and could provide valuable functional molecular information regarding tumor viability, and potentially treatment response. (orig.)

  4. Reliability of Early Magnetic Resonance Imaging (MRI) and Necessity of Repeating MRI in Noncooled and Cooled Infants With Neonatal Encephalopathy.

    Science.gov (United States)

    Chakkarapani, Elavazhagan; Poskitt, Kenneth J; Miller, Steven P; Zwicker, Jill G; Xu, Qi; Wong, Darren S T; Roland, Elke H; Hill, Alan; Chau, Vann

    2016-04-01

    In cooled newborns with encephalopathy, although late magnetic resonance imaging (MRI) scan (10-14 days of age) is reliable in predicting long-term outcome, it is unknown whether early scan (3-6 days of life) is. We compared the predominant pattern and extent of lesion between early and late MRI in 89 term neonates with neonatal encephalopathy. Forty-three neonates (48%) were cooled. The predominant pattern of lesions and the extent of lesion in the watershed region agreed near perfectly in noncooled (kappa = 0.94; k = 0.88) and cooled (k = 0.89; k = 0.87) infants respectively. There was perfect agreement in the extent of lesion in the basal nuclei in noncooled infants (k = 0.83) and excellent agreement in cooled infants (k = 0.67). Changes in extent of lesions on late MRI occurred in 19 of 89 infants, with higher risk in infants with hypoglycemia and moderate-severe lesions in basal nuclei. In most term neonates with neonatal encephalopathy, early MRI (relative to late scan) robustly predicts the predominant pattern and extent of injury. © The Author(s) 2015.

  5. Role of magnetic resonance imaging (MRI), MR spectroscopy (MRS) and other imaging modalities in breast cancer

    International Nuclear Information System (INIS)

    Sharma, Uma; Virendra Kumar; Jagannathan, N.R.

    2004-01-01

    Breast cancer is the commonest cancer among women world over and the diagnosis continues to generate fear and turmoil in the life of patients and their families. This article describes the currently available techniques used for screening primary and recurrent breast cancers and the evaluation of therapeutic response of breast cancer with special emphasis on MRI and MRS techniques. MRI, a noninvasive technique, provides anatomic images in multiple planes enabling tissue characterization. Contrast enhanced MR studies have been found to be useful in the diagnosis of small tumors in dense breast benign diseases from malignant ones. In vivo magnetic resonance spectroscopy (MRS) is another useful technique for diagnosis and for assessing the biochemical status of normal and diseased tissues. Being noninvasive, MR techniques can be used repetitively for assessment of response of the tumor to various therapeutic regimens and for evaluating the efficacy of drugs at both the structural and molecular level. An overview of the various aspects of different imaging modalities used in breast cancer research including various in vivo MR methodologies with clinical examples is presented in this review. (author)

  6. Animal MRI Core

    Data.gov (United States)

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  7. MRI reconstruction of multi-image acquisitions using a rank regularizer with data reordering

    Energy Technology Data Exchange (ETDEWEB)

    Adluru, Ganesh, E-mail: gadluru@gmail.com; Anderson, Jeffrey [UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah 84108 (United States); Gur, Yaniv [IBM Almaden Research Center, San Jose, California 95120 (United States); Chen, Liyong; Feinberg, David [Advanced MRI Technologies, Sebastpool, California, 95472 (United States); DiBella, Edward V. R. [UCAIR, Department of Radiology, University of Utah, Salt Lake City, Utah 84108 and Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112 (United States)

    2015-08-15

    Purpose: To improve rank constrained reconstructions for undersampled multi-image MRI acquisitions. Methods: Motivated by the recent developments in low-rank matrix completion theory and its applicability to rapid dynamic MRI, a new reordering-based rank constrained reconstruction of undersampled multi-image data that uses prior image information is proposed. Instead of directly minimizing the nuclear norm of a matrix of estimated images, the nuclear norm of reordered matrix values is minimized. The reordering is based on the prior image estimates. The method is tested on brain diffusion imaging data and dynamic contrast enhanced myocardial perfusion data. Results: Good quality images from data undersampled by a factor of three for diffusion imaging and by a factor of 3.5 for dynamic cardiac perfusion imaging with respiratory motion were obtained. Reordering gave visually improved image quality over standard nuclear norm minimization reconstructions. Root mean squared errors with respect to ground truth images were improved by ∼18% and ∼16% with reordering for diffusion and perfusion applications, respectively. Conclusions: The reordered low-rank constraint is a way to inject prior image information that offers improvements over a standard low-rank constraint for undersampled multi-image MRI reconstructions.

  8. MRI reconstruction of multi-image acquisitions using a rank regularizer with data reordering

    International Nuclear Information System (INIS)

    Adluru, Ganesh; Anderson, Jeffrey; Gur, Yaniv; Chen, Liyong; Feinberg, David; DiBella, Edward V. R.

    2015-01-01

    Purpose: To improve rank constrained reconstructions for undersampled multi-image MRI acquisitions. Methods: Motivated by the recent developments in low-rank matrix completion theory and its applicability to rapid dynamic MRI, a new reordering-based rank constrained reconstruction of undersampled multi-image data that uses prior image information is proposed. Instead of directly minimizing the nuclear norm of a matrix of estimated images, the nuclear norm of reordered matrix values is minimized. The reordering is based on the prior image estimates. The method is tested on brain diffusion imaging data and dynamic contrast enhanced myocardial perfusion data. Results: Good quality images from data undersampled by a factor of three for diffusion imaging and by a factor of 3.5 for dynamic cardiac perfusion imaging with respiratory motion were obtained. Reordering gave visually improved image quality over standard nuclear norm minimization reconstructions. Root mean squared errors with respect to ground truth images were improved by ∼18% and ∼16% with reordering for diffusion and perfusion applications, respectively. Conclusions: The reordered low-rank constraint is a way to inject prior image information that offers improvements over a standard low-rank constraint for undersampled multi-image MRI reconstructions

  9. AUTOMATED CLASSIFICATION AND SEGREGATION OF BRAIN MRI IMAGES INTO IMAGES CAPTURED WITH RESPECT TO VENTRICULAR REGION AND EYE-BALL REGION

    Directory of Open Access Journals (Sweden)

    C. Arunkumar

    2014-05-01

    Full Text Available Magnetic Resonance Imaging (MRI images of the brain are used for detection of various brain diseases including tumor. In such cases, classification of MRI images captured with respect to ventricular and eye ball regions helps in automated location and classification of such diseases. The methods employed in the paper can segregate the given MRI images of brain into images of brain captured with respect to ventricular region and images of brain captured with respect to eye ball region. First, the given MRI image of brain is segmented using Particle Swarm Optimization (PSO algorithm, which is an optimized algorithm for MRI image segmentation. The algorithm proposed in the paper is then applied on the segmented image. The algorithm detects whether the image consist of a ventricular region or an eye ball region and classifies it accordingly.

  10. Automatic delineation of brain regions on MRI and PET images from the pig.

    Science.gov (United States)

    Villadsen, Jonas; Hansen, Hanne D; Jørgensen, Louise M; Keller, Sune H; Andersen, Flemming L; Petersen, Ida N; Knudsen, Gitte M; Svarer, Claus

    2018-01-15

    The increasing use of the pig as a research model in neuroimaging requires standardized processing tools. For example, extraction of regional dynamic time series from brain PET images requires parcellation procedures that benefit from being automated. Manual inter-modality spatial normalization to a MRI atlas is operator-dependent, time-consuming, and can be inaccurate with lack of cortical radiotracer binding or skull uptake. A parcellated PET template that allows for automatic spatial normalization to PET images of any radiotracer. MRI and [ 11 C]Cimbi-36 PET scans obtained in sixteen pigs made the basis for the atlas. The high resolution MRI scans allowed for creation of an accurately averaged MRI template. By aligning the within-subject PET scans to their MRI counterparts, an averaged PET template was created in the same space. We developed an automatic procedure for spatial normalization of the averaged PET template to new PET images and hereby facilitated transfer of the atlas regional parcellation. Evaluation of the automatic spatial normalization procedure found the median voxel displacement to be 0.22±0.08mm using the MRI template with individual MRI images and 0.92±0.26mm using the PET template with individual [ 11 C]Cimbi-36 PET images. We tested the automatic procedure by assessing eleven PET radiotracers with different kinetics and spatial distributions by using perfusion-weighted images of early PET time frames. We here present an automatic procedure for accurate and reproducible spatial normalization and parcellation of pig PET images of any radiotracer with reasonable blood-brain barrier penetration. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Intersection based motion correction of multislice MRI for 3-D in utero fetal brain image formation.

    Science.gov (United States)

    Kim, Kio; Habas, Piotr A; Rousseau, Francois; Glenn, Orit A; Barkovich, Anthony J; Studholme, Colin

    2010-01-01

    In recent years, postprocessing of fast multislice magnetic resonance imaging (MRI) to correct fetal motion has provided the first true 3-D MR images of the developing human brain in utero. Early approaches have used reconstruction based algorithms, employing a two-step iterative process, where slices from the acquired data are realigned to an approximate 3-D reconstruction of the fetal brain, which is then refined further using the improved slice alignment. This two step slice-to-volume process, although powerful, is computationally expensive in needing a 3-D reconstruction, and is limited in its ability to recover subvoxel alignment. Here, we describe an alternative approach which we term slice intersection motion correction (SIMC), that seeks to directly co-align multiple slice stacks by considering the matching structure along all intersecting slice pairs in all orthogonally planned slices that are acquired in clinical imaging studies. A collective update scheme for all slices is then derived, to simultaneously drive slices into a consistent match along their lines of intersection. We then describe a 3-D reconstruction algorithm that, using the final motion corrected slice locations, suppresses through-plane partial volume effects to provide a single high isotropic resolution 3-D image. The method is tested on simulated data with known motions and is applied to retrospectively reconstruct 3-D images from a range of clinically acquired imaging studies. The quantitative evaluation of the registration accuracy for the simulated data sets demonstrated a significant improvement over previous approaches. An initial application of the technique to studying clinical pathology is included, where the proposed method recovered up to 15 mm of translation and 30 degrees of rotation for individual slices, and produced full 3-D reconstructions containing clinically useful additional information not visible in the original 2-D slices.

  12. A technique to consider mismatches between fMRI and EEG/MEG sources for fMRI-constrained EEG/MEG source imaging: a preliminary simulation study

    International Nuclear Information System (INIS)

    Im, Chang-Hwan; Lee, Soo Yeol

    2006-01-01

    fMRI-constrained EEG/MEG source imaging can be a powerful tool in studying human brain functions with enhanced spatial and temporal resolutions. Recent studies on the combination of fMRI and EEG/MEG have suggested that fMRI prior information could be readily implemented by simply imposing different weighting factors to cortical sources overlapping with the fMRI activations. It has been also reported, however, that such a hard constraint may cause severe distortions or elimination of meaningful EEG/MEG sources when there are distinct mismatches between the fMRI activations and the EEG/MEG sources. If one wants to obtain the actual EEG/MEG source locations and uses the fMRI prior information as just an auxiliary tool to enhance focality of the distributed EEG/MEG sources, it is reasonable to weaken the strength of fMRI constraint when severe mismatches between fMRI and EEG/MEG sources are observed. The present study suggests an efficient technique to automatically adjust the strength of fMRI constraint according to the mismatch level. The use of the proposed technique rarely affects the results of conventional fMRI-constrained EEG/MEG source imaging if no major mismatch between the two modalities is detected; while the new results become similar to those of typical EEG/MEG source imaging without fMRI constraint if the mismatch level is significant. A preliminary simulation study using realistic EEG signals demonstrated that the proposed technique can be a promising tool to selectively apply fMRI prior information to EEG/MEG source imaging

  13. Magnetic resonance imaging (MRI) in diffuse liver diseases. Comparison with CT

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Masaharu; Ebara, Masaaki; Ohto, Masao

    1987-06-01

    MRI (Magnetic Resonance Imaging) was performed in 74 patients with chronic hepatitis, liver cirrhosis, idiopathic portal hypertension, Budd-Chiari syndrome, extrahepatic protal vein occlusion, Wilson disease and hemochromatosis. We measured relaxation time of the liver and the spleen in these patients and compared MRI with CT in the diagnostic capability. MRI was superior to plain CT in the detection of collateral vessels in liver cirrhosis and extrahepatic protal vein occlusion. MRI could also demonstrate the occluded part of the inferior vena cava in Budd-Chiari syndrome. However, MRI was almost the same as CT in the visualization of the hepatic configuration in liver cirrhosis. In liver cirrhosis, T1 values of the liver and the spleen were longer than those in normal controls, and T1 values of the liver were correlated with ICG R-15. Hepatic T1 values in Budd-Chiari syndrome were longer than those in normal controls.

  14. An availability of brain magnetic resonance imaging (MRI) in the early diagnosis of latent hepatic encephalopathy

    International Nuclear Information System (INIS)

    Kuwahara, Noaki; Tanabe, Masako; Fujiwara, Akiko; Minato, Takeshi; Sasaki, Hiromasa; Higashi, Toshihiro; Tsuji, Takao.

    1996-01-01

    Brain MRI was carried out in patients with chronic liver diseases. No abnormal findings were recognized in patients with chronic viral hepatitis, while 59.2% of cirrhotics showed a symmetrically strong signal in basal ganglia on T1 weighted image in MRI. This finding significantly related with lowered Fischer's ratio of serum amino acid, increased levels of serum phenylalanine, tyrosine and hyaluronic acid, prolonged prothrombin time and decreased platelet counts in the peripheral blood. Overt hepatic encephalopathy was observed in 6 of 34 patients with the strong signal in MRI during follow-up period, while none of patients without that finding developed hepatic encephalopathy. These results have indicated that the strong signal in basal ganglia on MRI appears in cirrhotic patients with severe liver dysfunction, and it is an useful index in the early diagnosis of latent hepatic encephalopathy. An improvement of this MRI finding was not observed by long-term oral administration of branched-chain amino acid. (author)

  15. Semi-automatic delineation using weighted CT-MRI registered images for radiotherapy of nasopharyngeal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Fitton, I. [European Georges Pompidou Hospital, Department of Radiology, 20 rue Leblanc, 75015, Paris (France); Cornelissen, S. A. P. [Image Sciences Institute, UMC, Department of Radiology, P.O. Box 85500, 3508 GA Utrecht (Netherlands); Duppen, J. C.; Rasch, C. R. N.; Herk, M. van [The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Department of Radiotherapy, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Steenbakkers, R. J. H. M. [University Medical Center Groningen, Department of Radiation Oncology, Hanzeplein 1, 9713 GZ Groningen (Netherlands); Peeters, S. T. H. [UZ Gasthuisberg, Herestraat 49, 3000 Leuven, Belgique (Belgium); Hoebers, F. J. P. [Maastricht University Medical Center, Department of Radiation Oncology (MAASTRO clinic), GROW School for Oncology and Development Biology Maastricht, 6229 ET Maastricht (Netherlands); Kaanders, J. H. A. M. [UMC St-Radboud, Department of Radiotherapy, Geert Grooteplein 32, 6525 GA Nijmegen (Netherlands); Nowak, P. J. C. M. [ERASMUS University Medical Center, Department of Radiation Oncology,Groene Hilledijk 301, 3075 EA Rotterdam (Netherlands)

    2011-08-15

    Purpose: To develop a delineation tool that refines physician-drawn contours of the gross tumor volume (GTV) in nasopharynx cancer, using combined pixel value information from x-ray computed tomography (CT) and magnetic resonance imaging (MRI) during delineation. Methods: Operator-guided delineation assisted by a so-called ''snake'' algorithm was applied on weighted CT-MRI registered images. The physician delineates a rough tumor contour that is continuously adjusted by the snake algorithm using the underlying image characteristics. The algorithm was evaluated on five nasopharyngeal cancer patients. Different linear weightings CT and MRI were tested as input for the snake algorithm and compared according to contrast and tumor to noise ratio (TNR). The semi-automatic delineation was compared with manual contouring by seven experienced radiation oncologists. Results: A good compromise for TNR and contrast was obtained by weighing CT twice as strong as MRI. The new algorithm did not notably reduce interobserver variability, it did however, reduce the average delineation time by 6 min per case. Conclusions: The authors developed a user-driven tool for delineation and correction based a snake algorithm and registered weighted CT image and MRI. The algorithm adds morphological information from CT during the delineation on MRI and accelerates the delineation task.

  16. Morphometric MRI changes in intracranial hypertension due to cerebral venous thrombosis: a retrospective imaging study

    International Nuclear Information System (INIS)

    Dong, Cheng; Zheng, Ying-mei; Li, Xiao-li; Wang, He-xiang; Hao, Da-peng; Nie, Pei; Pang, Jing; Xu, Wen-jian

    2016-01-01

    Aim: To evaluate whether some magnetic resonance imaging (MRI) signs suggesting idiopathic intracranial hypertension (IIH) could also be found in intracranial hypertension (IH) due to cerebral venous thrombosis (CVT) and to assess their possible contribution to diagnosing this disorder. Materials and methods: Thirty-one patients with IH due to CVT were evaluated prospectively using MRI. A group of 33 age- and sex-matched healthy volunteers served as controls. The optic nerve and sheath, pituitary gland, and ventricles were assessed. The prevalence of each imaging feature was compared between the two groups. Results: Optic nerve sheath (ONS) dilatation and decreased pituitary gland height were the most valid signs suggesting IH in CVT patients: sensitivity 70.97% and 87.1%, respectively; specificity 96.97% and 72.73%, respectively; area under the curve 0.840 and 0.809, respectively. The MRI finding that showed the strongest association with IH in CVT patients was ONS dilatation (odds ratio 78.5). Conclusions: The combination of T1-weighted volumetric MRI and magnetic resonance venography could be helpful for diagnosing IH with CVT. Abnormalities of the ONS and the pituitary gland were reliable diagnostic signs for IH due to CVT. - Highlights: • We compared the prevalence of MRI imaging features between IH patients due to CVT and healthy volunteers. • Several MRI imaging features occur more frequently in IH patients due to CVT. • Abnormalities of the ONS and the pituitary gland were reliable diagnostic signs for IH due to CVT.

  17. Functional and molecular imaging with MRI: potential applications in paediatric radiology

    International Nuclear Information System (INIS)

    Arthurs, Owen J.; Gallagher, Ferdia A.

    2011-01-01

    MRI is a very versatile tool for noninvasive imaging and it is particularly attractive as an imaging technique in paediatric patients given the absence of ionizing radiation. Recent advances in the field of MRI have enabled tissue function to be probed noninvasively, and increasingly MRI is being used to assess cellular and molecular processes. For example, dynamic contrast-enhanced MRI has been used to assess tissue vascularity, diffusion-weighted imaging can quantify molecular movements of water in tissue compartments and MR spectroscopy provides a quantitative assessment of metabolite levels. A number of targeted contrast agents have been developed that bind specifically to receptors on the vascular endothelium or cell surface and there are several MR methods for labelling cells and tracking cellular movements. Hyperpolarization techniques have the capability of massively increasing the sensitivity of MRI and these have been used to image tissue pH, successful response to drug treatment as well as imaging the microstructure of the lungs. Although there are many challenges to be overcome before these techniques can be translated into routine paediatric imaging, they could potentially be used to aid diagnosis, predict disease outcome, target biopsies and determine treatment response noninvasively. (orig.)

  18. Brain single-photon emission tomography with {sup 99m}Tc-HMPAO in neuropsychiatric systemic lupus erythematosus: relations with EEG and MRI findings and clinical manifestations

    Energy Technology Data Exchange (ETDEWEB)

    Colamussi, P. [Dept. of Nuclear Medicine, Univ. of Ferrara (Italy); Giganti, M. [Dept. of Nuclear Medicine, Univ. of Ferrara (Italy); Cittanti, C. [Dept. of Nuclear Medicine, Univ. of Ferrara (Italy); Dovigo, L. [Inst. of Neurology, Univ. of Ferrara (Italy); Trotta, F. [Inst. of Neurology, Univ. of Ferrara (Italy); Tola, M.R. [Div. of Rheumatology, S. Anna Hospital, Ferrara (Italy); Tamarozzi, R. [Radiology Dept., S. Anna Hospital, Ferrara (Italy); Lucignani, G. [INB-CNR Dept. of Nuclear Medicine, H.S. Raffaele, Milan (Italy); Piffanelli, A. [Dept. of Nuclear Medicine, Univ. of Ferrara (Italy)

    1995-01-01

    In the reported study the role of single-photon emission tomography (SPET) with technetium-99m hexamethylpropylene amine oxime (HMPAO) in the evaluation of CNS involvement in SLE was assessed and the relations between SPET perfusion defects, EEG examination, magnetic resonance imaging (MRI) findings and clinical presentation were examined. Twenty SLE patients with different NP manifestations were studied. Multiple areas of hypoperfusion, especially in the territory of the middle cerebral artery, were demonstrated by SPET analysis in all 20 patients. The number of hypoperfused areas and the degree of hypoperfusion, expressed by an asymmetry index (AI), were more marked in patients with multiple NP manifestations. MRI and EEG evaluations were positive for 14 of 18 and for 12 of 20 patients, respectively. In the patients with positive SPET and MRI, 87 MRI focal lesions and 63 hypoperfused areas were found, and for 51 of these 63 at least one MRI lesion was found in the same anatomical region. SPET examination of patients with a normal EEG showed fewer hypoperfused areas and a lower degree of asymmetry compared to patients with an abnormal EEG. SPET of patients with focal EEG abnormalities showed more hypoperfused areas (difference not statistically significant) and a higher AI than did SPET of the patients with diffuse EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities had co-localized hypoperfused areas and in two of these seven no detectable MRI lesions were found. The analysis of SPET and NP manifestations showed that 12 of 20 patients had at least one positive correlation, always involving the areas with the highest AI. In total, 51/88 (58%) hypoperfused areas correlated with the MRI findings and 31/88 (35%) with NP manifestations; for seven of the latter no concurrent MRI lesions were detected in the same anatomical region. (orig.)

  19. Brain single-photon emission tomography with 99mTc-HMPAO in neuropsychiatric systemic lupus erythematosus: relations with EEG and MRI findings and clinical manifestations

    International Nuclear Information System (INIS)

    Colamussi, P.; Giganti, M.; Cittanti, C.; Dovigo, L.; Trotta, F.; Tola, M.R.; Tamarozzi, R.; Lucignani, G.; Piffanelli, A.

    1995-01-01

    In the reported study the role of single-photon emission tomography (SPET) with technetium-99m hexamethylpropylene amine oxime (HMPAO) in the evaluation of CNS involvement in SLE was assessed and the relations between SPET perfusion defects, EEG examination, magnetic resonance imaging (MRI) findings and clinical presentation were examined. Twenty SLE patients with different NP manifestations were studied. Multiple areas of hypoperfusion, especially in the territory of the middle cerebral artery, were demonstrated by SPET analysis in all 20 patients. The number of hypoperfused areas and the degree of hypoperfusion, expressed by an asymmetry index (AI), were more marked in patients with multiple NP manifestations. MRI and EEG evaluations were positive for 14 of 18 and for 12 of 20 patients, respectively. In the patients with positive SPET and MRI, 87 MRI focal lesions and 63 hypoperfused areas were found, and for 51 of these 63 at least one MRI lesion was found in the same anatomical region. SPET examination of patients with a normal EEG showed fewer hypoperfused areas and a lower degree of asymmetry compared to patients with an abnormal EEG. SPET of patients with focal EEG abnormalities showed more hypoperfused areas (difference not statistically significant) and a higher AI than did SPET of the patients with diffuse EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities. Seven of 11 anatomical regions with focal EEG abnormalities had co-localized hypoperfused areas and in two of these seven no detectable MRI lesions were found. The analysis of SPET and NP manifestations showed that 12 of 20 patients had at least one positive correlation, always involving the areas with the highest AI. In total, 51/88 (58%) hypoperfused areas correlated with the MRI findings and 31/88 (35%) with NP manifestations; for seven of the latter no concurrent MRI lesions were detected in the same anatomical region. (orig.)

  20. MRI methods for pulmonary ventilation and perfusion imaging; Methoden der MRT zur Ventilations- und Perfusionsbildgebung der Lunge

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, G. [Universitaetsspital Basel, Klinik fuer Radiologie und Nuklearmedizin, Basel (Switzerland); Bauman, G. [Universitaetsspital Basel, Klinik fuer Radiologie und Nuklearmedizin - Radiologische Physik, Basel (Switzerland)

    2016-02-15

    Separate assessment of respiratory mechanics, gas exchange and pulmonary circulation is essential for the diagnosis and therapy of pulmonary diseases. Due to the global character of the information obtained clinical lung function tests are often not sufficiently specific in the differential diagnosis or have a limited sensitivity in the detection of early pathological changes. The standard procedures of pulmonary imaging are computed tomography (CT) for depiction of the morphology as well as perfusion/ventilation scintigraphy and single photon emission computed tomography (SPECT) for functional assessment. Magnetic resonance imaging (MRI) with hyperpolarized gases, O{sub 2}-enhanced MRI, MRI with fluorinated gases and Fourier decomposition MRI (FD-MRI) are available for assessment of pulmonary ventilation. For assessment of pulmonary perfusion dynamic contrast-enhanced MRI (DCE-MRI), arterial spin labeling (ASL) and FD-MRI can be used. Imaging provides a more precise insight into the pathophysiology of pulmonary function on a regional level. The advantages of MRI are a lack of ionizing radiation, which allows a protective acquisition of dynamic data as well as the high number of available contrasts and therefore accessible lung function parameters. Sufficient clinical data exist only for certain applications of DCE-MRI. For the other techniques, only feasibility studies and case series of different sizes are available. The clinical applicability of hyperpolarized gases is limited for technical reasons. The clinical application of the techniques described, except for DCE-MRI, should be restricted to scientific studies. (orig.) [German] Die separate Beurteilung von Atemmechanik, Gasaustauschprozessen und Lungenzirkulation ist wesentlich fuer die Diagnose und Therapie von Lungenerkrankungen. Klinische Lungenfunktionstests sind aufgrund ihrer zumeist nur globalen Aussage oft nicht hinreichend spezifisch in der Differenzialdiagnostik oder eingeschraenkt sensitiv bei der

  1. 2D dose distribution images of a hybrid low field MRI-γ detector

    Energy Technology Data Exchange (ETDEWEB)

    Abril, A., E-mail: ajabrilf@unal.edu.co; Agulles-Pedrós, L., E-mail: lagullesp@unal.edu.co [Medical Physics Group, Physics department, Universidad Nacional de Colombia, Bogotá (Colombia)

    2016-07-07

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the {sup 99m}Tc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  2. 2D dose distribution images of a hybrid low field MRI-γ detector

    International Nuclear Information System (INIS)

    Abril, A.; Agulles-Pedrós, L.

    2016-01-01

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the "9"9"mTc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  3. 2D dose distribution images of a hybrid low field MRI-γ detector

    Science.gov (United States)

    Abril, A.; Agulles-Pedrós, L.

    2016-07-01

    The proposed hybrid system is a combination of a low field MRI and dosimetric gel as a γ detector. The readout system is based on the polymerization process induced by the gel radiation. A gel dose map is obtained which represents the functional part of hybrid image alongside with the anatomical MRI one. Both images should be taken while the patient with a radiopharmaceutical is located inside the MRI system with a gel detector matrix. A relevant aspect of this proposal is that the dosimetric gel has never been used to acquire medical images. The results presented show the interaction of the 99mTc source with the dosimetric gel simulated in Geant4. The purpose was to obtain the planar γ 2D-image. The different source configurations are studied to explore the ability of the gel as radiation detector through the following parameters; resolution, shape definition and radio-pharmaceutical concentration.

  4. Transmission imaging for registration of ictal and interictal single-photon emission tomography, magnetic resonance imaging and electroencephalography

    Energy Technology Data Exchange (ETDEWEB)

    Sipilae, O. [Epilepsy Unit, Neurology, Hospital for Children and Adolescents, Helsinki University Central Hospital (Finland); Laboratory of Biomedical Engineering, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT (Finland); Nikkinen, P.; Liewendahl, K. [Division of Nuclear Medicine, Laboratory Department, Helsinki University Central Hospital (Finland); Savolainen, S. [Division of Nuclear Medicine, Laboratory Department, Helsinki University Central Hospital (Finland); Department of Radiology, Helsinki University Central Hospital (Finland); Granstroem, M.-L.; Gaily, E. [Epilepsy Unit, Neurology, Hospital for Children and Adolescents, Helsinki University Central Hospital (Finland); Poutanen, V.-P. [Department of Radiology, Helsinki University Central Hospital (Finland); Pohjonen, H. [Technology Development Centre, P.O. Box 69, 00101 Helsinki (Finland)

    2000-02-01

    A method developed for registration of ictal and interictal single-photon emission tomography (SPET), magnetic resonance imaging (MRI) and electroencephalography (EEG) is described. For SPET studies, technetium-99m ethyl cysteinate dimer (ECD) was injected intravenously while the patient was monitored on video-EEG to document the ictal or interictal state. Imaging was performed using a triple-head gamma camera equipped with a transmission imaging device using a gadolinium-153 source. The images (128 x 128 pixels, voxel size 3.7 x 3.7 x 3.6 mm{sup 3}) were reconstructed using an iterative algorithm and postfiltered with a Wiener filter. The gold-plated silver electrodes on the patient's scalp were utilized as markers for registration of the ictal and interictal SPET images, as these metallic markers were clearly seen on the transmission images. Fitting of the marker sets was based on a non-iterative least squares method. The interictal SPET image was subtracted from the ictal image after scaling. The T1-weighted MPRAGE MR images with voxel size of 1.0 x 1.0 x 1.0 mm{sup 3} were obtained with a 1.5-T scanner. For registration of MR and subtraction SPET images, the external marker set of the ictal SPET study was fitted to the surface of the head segmented from MR images. The SPET registration was tested with a phantom experiment. Registration of ictal and interictal SPET in five patient studies resulted in a 2-mm RMS residual of the marker sets. The estimated RMS error of registration in the final result combining locations of the electrodes, subtraction SPET and MR images was 3-5 mm. In conclusion, transmission imaging can be utilized for an accurate and easily implemented registration procedure for ictal and interictal SPET, MRI and EEG. (orig.)

  5. Evaluation of electrode position in deep brain stimulation by image fusion (MRI and CT)

    Energy Technology Data Exchange (ETDEWEB)

    Barnaure, I.; Lovblad, K.O.; Vargas, M.I. [Geneva University Hospital, Department of Neuroradiology, Geneva 14 (Switzerland); Pollak, P.; Horvath, J.; Boex, C.; Burkhard, P. [Geneva University Hospital, Department of Neurology, Geneva (Switzerland); Momjian, S. [Geneva University Hospital, Department of Neurosurgery, Geneva (Switzerland); Remuinan, J. [Geneva University Hospital, Department of Radiology, Geneva (Switzerland)

    2015-09-15

    Imaging has an essential role in the evaluation of correct positioning of electrodes implanted for deep brain stimulation (DBS). Although MRI offers superior anatomic visualization of target sites, there are safety concerns in patients with implanted material; imaging guidelines are inconsistent and vary. The fusion of postoperative CT with preoperative MRI images can be an alternative for the assessment of electrode positioning. The purpose of this study was to assess the accuracy of measurements realized on fused images (acquired without a stereotactic frame) using a manufacturer-provided software. Data from 23 Parkinson's disease patients who underwent bilateral electrode placement for subthalamic nucleus (STN) DBS were acquired. Preoperative high-resolution T2-weighted sequences at 3 T, and postoperative CT series were fused using a commercially available software. Electrode tip position was measured on the obtained images in three directions (in relation to the midline, the AC-PC line and an AC-PC line orthogonal, respectively) and assessed in relation to measures realized on postoperative 3D T1 images acquired at 1.5 T. Mean differences between measures carried out on fused images and on postoperative MRI lay between 0.17 and 0.97 mm. Fusion of CT and MRI images provides a safe and fast technique for postoperative assessment of electrode position in DBS. (orig.)

  6. Learning Computational Models of Video Memorability from fMRI Brain Imaging.

    Science.gov (United States)

    Han, Junwei; Chen, Changyuan; Shao, Ling; Hu, Xintao; Han, Jungong; Liu, Tianming

    2015-08-01

    Generally, various visual media are unequally memorable by the human brain. This paper looks into a new direction of modeling the memorability of video clips and automatically predicting how memorable they are by learning from brain functional magnetic resonance imaging (fMRI). We propose a novel computational framework by integrating the power of low-level audiovisual features and brain activity decoding via fMRI. Initially, a user study experiment is performed to create a ground truth database for measuring video memorability and a set of effective low-level audiovisual features is examined in this database. Then, human subjects' brain fMRI data are obtained when they are watching the video clips. The fMRI-derived features that convey the brain activity of memorizing videos are extracted using a universal brain reference system. Finally, due to the fact that fMRI scanning is expensive and time-consuming, a computational model is learned on our benchmark dataset with the objective of maximizing the correlation between the low-level audiovisual features and the fMRI-derived features using joint subspace learning. The learned model can then automatically predict the memorability of videos without fMRI scans. Evaluations on publically available image and video databases demonstrate the effectiveness of the proposed framework.

  7. Magnetic resonance imaging (MRI) of avascular necrosis of the femoral head

    International Nuclear Information System (INIS)

    Kokubo, Takashi; Yoshikawa, Kohki; Aoki, Shigeki

    1987-01-01

    Thirty-seven patients with the clinical diagnosis of or suspicious of avascular necrosis (AN) of the femoral head were examined by magnetic resonance imaging (MRI). In all patients with AN confirmed from clinical symptoms, past history and plain radiographs, MRI demonstrated abnormal low intensity area in the necrosed femoral head. The abnormal findings on MRI were divided into three patterns: low signal intensity occupying the greater part of the femoral head (type A), low signal intensity localized in the periphery (type B), ring-shaped or band-like low signal intensity (type C). No correlation was found among MRI patterns, radiographic findings and radionuclide bone scan images, except that the type C was not found in the stage IV determined radiographically. In the patients suspicious of AN, the positive rate of MRI was higher than that of radionuclide scan. Abnormal findings on only MRI may not necessarily indicate AN. However, such a patient must be kept under observation, because the possibility exists that only MRI detects early or asymptomatic AN of the femoral head. (author)

  8. Magnetic resonance imaging (MRI) of avascular necrosis of the femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Kokubo, Takashi; Yoshikawa, Kohki; Aoki, Shigeki

    1987-05-01

    Thirty-seven patients with the clinical diagnosis of or suspicious of avascular necrosis (AN) of the femoral head were examined by magnetic resonance imaging (MRI). In all patients with AN confirmed from clinical symptoms, past history and plain radiographs, MRI demonstrated abnormal low intensity area in the necrosed femoral head. The abnormal findings on MRI were divided into three patterns: low signal intensity occupying the greater part of the femoral head (type A), low signal intensity localized in the periphery (type B), ring-shaped or band-like low signal intensity (type C). No correlation was found among MRI patterns, radiographic findings and radionuclide bone scan images, except that the type C was not found in the stage IV determined radiographically. In the patients suspicious of AN, the positive rate of MRI was higher than that of radionuclide scan. Abnormal findings on only MRI may not necessarily indicate AN. However, such a patient must be kept under observation, because the possibility exists that only MRI detects early or asymptomatic AN of the femoral head.

  9. Physiological and technical limitations of functional magnetic resonance imaging (fMRI) - consequences for clinical use

    International Nuclear Information System (INIS)

    Wuestenberg, T.; Jordan, K.; Giesel, F.L.; Villringer, A.

    2003-01-01

    Functional magnetic resonance imaging (fMRI) is the most common noninvasive technique in functional neuroanatomy. The capabilities and limitations of the method will be discussed based on a short review of the current knowledge about the neurovascular relationship. The focus of this article is on current methodical and technical problems regarding fMRI-based detection and localization of neuronal activity. Main error sources and their influence on the reliability and validity of fMRI-methods are presented. Appropriate solution strategies will be proposed and evaluated. Finally, the clinical relevance of MR-based diagnostic methods are discussed. (orig.) [de

  10. Comparative study on developmental stages of the clavicle by postmortem MRI and CT imaging

    DEFF Research Database (Denmark)

    Larsen, Sara Tangmose; Lynnerup, Niels; Jensen, K.E.

    2013-01-01

    Objectives: The developmental stages of the clavicles are important for forensic age estimation purposes in adolescents. This study compares the 4-stage system to evaluate the ossification of the medial end of the clavicle as visualized by magnetic resonance imaging (MRI) and computed tomography...... (CT). As several forensic institutes routinely perform CT scans, the large amount of available data may serve as reference sample for MRI in specific cases. Material and methods: This prospective study included an MRI and CT scan of 47 autopsy cases performed prior to medico-legal autopsy (age range...

  11. Software Toolbox for Low-Frequency Conductivity and Current Density Imaging Using MRI.

    Science.gov (United States)

    Sajib, Saurav Z K; Katoch, Nitish; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2017-11-01

    Low-frequency conductivity and current density imaging using MRI includes magnetic resonance electrical impedance tomography (MREIT), diffusion tensor MREIT (DT-MREIT), conductivity tensor imaging (CTI), and magnetic resonance current density imaging (MRCDI). MRCDI and MREIT provide current density and isotropic conductivity images, respectively, using current-injection phase MRI techniques. DT-MREIT produces anisotropic conductivity tensor images by incorporating diffusion weighted MRI into MREIT. These current-injection techniques are finding clinical applications in diagnostic imaging and also in transcranial direct current stimulation (tDCS), deep brain stimulation (DBS), and electroporation where treatment currents can function as imaging currents. To avoid adverse effects of nerve and muscle stimulations due to injected currents, conductivity tensor imaging (CTI) utilizes B1 mapping and multi-b diffusion weighted MRI to produce low-frequency anisotropic conductivity tensor images without injecting current. This paper describes numerical implementations of several key mathematical functions for conductivity and current density image reconstructions in MRCDI, MREIT, DT-MREIT, and CTI. To facilitate experimental studies of clinical applications, we developed a software toolbox for these low-frequency conductivity and current density imaging methods. This MR-based conductivity imaging (MRCI) toolbox includes 11 toolbox functions which can be used in the MATLAB environment. The MRCI toolbox is available at http://iirc.khu.ac.kr/software.html . Its functions were tested by using several experimental datasets, which are provided together with the toolbox. Users of the toolbox can focus on experimental designs and interpretations of reconstructed images instead of developing their own image reconstruction softwares. We expect more toolbox functions to be added from future research outcomes. Low-frequency conductivity and current density imaging using MRI includes

  12. MRI-only lesions: application of diffusion-weighted imaging obviates unnecessary MR-guided breast biopsies

    Energy Technology Data Exchange (ETDEWEB)

    Spick, Claudio; Pinker-Domenig, Katja; Helbich, Thomas H.; Baltzer, Pascal A. [Medical University of Vienna (AKH), General Hospital Vienna, Department of Biomedical Imaging and Image-guided Therapy, Division of Molecular and Gender Imaging, Wien (Austria); Rudas, Margaretha [Medical University of Vienna (AKH), Clinical Institute of Pathology, Wien (Austria)

    2014-06-15

    To assess if the application of diffusion-weighted imaging (DWI) obviates unnecessary MR-guided biopsies in suspicious breast lesions visible only on contrast-enhanced MRI (CE-MRI). This institutional review board (IRB)-approved, retrospective, single-centre study included 101 patients (mean age, 49.5; SD 13.9 years) who underwent additional DWI at 1.5 T prior to MRI-guided biopsy of 104 lesions classified as suspicious for malignancy and visible on CE-MRI only. An experienced radiologist, blinded to histopathologic and follow-up results, measured apparent diffusion coefficient (ADC) values obtained from DWI. Diagnostic accuracy was investigated using receiver operating characteristics (ROC) analysis. Histopathology revealed 20 malignant and 84 benign lesions. Lesions were masses in 61 (15 malignant, 24.6 %) and non-masses in 43 cases (five malignant, 11.6 %). Mean ADC values were 1.53 ± 0.38 x 10{sup -3} mm{sup 2}/s in benign lesions and 1.06 ± 0.27 x 10{sup -3} mm{sup 2}/s in malignant lesions. ROC analysis revealed exclusively benign lesions if ADC values were greater than 1.58 x 10{sup -3} mm{sup 2}/s. As a consequence, 29 false-positive biopsies (34.5 %) could have been avoided without any false-negative findings. Both in mass and in non-mass lesions, rule-in and rule-out criteria were identified using flexible ADC thresholds based on ROC analysis. Additional application of DWI in breast lesions visible only on MRI can avoid false-positive, MR-guided biopsies. Thus, DWI should be an integral part of breast MRI protocols. (orig.)

  13. Current and future diagnostic tools for traumatic brain injury: CT, conventional MRI, and diffusion tensor imaging.

    Science.gov (United States)

    Brody, David L; Mac Donald, Christine L; Shimony, Joshua S

    2015-01-01

    Brain imaging plays a key role in the assessment of traumatic brain injury. In this review, we present our perspectives on the use of computed tomography (CT), conventional magnetic resonance imaging (MRI), and newer advanced modalities such as diffusion tensor imaging. Specifically, we address assessment for immediately life-threatening intracranial lesions (noncontrast head CT), assessment of progression of intracranial lesions (noncontrast head CT), documenting intracranial abnormalities for medicolegal reasons (conventional MRI with blood-sensitive sequences), presurgical planning for post-traumatic epilepsy (high spatial resolution conventional MRI), early prognostic decision making (conventional MRI with diffusion-weighted imaging), prognostic assessment for rehabilitative planning (conventional MRI and possibly diffusion tensor imaging in the future), stratification of subjects and pharmacodynamic tracking of targeted therapies in clinical trials (specific MRI sequences or positron emission tomography (PET) ligands, e.g., diffusion tensor imaging for traumatic axonal injury). We would like to emphasize that all of these methods, especially the newer research approaches, require careful radiologic-pathologic validation for optimal interpretation. We have taken this approach in a mouse model of pericontusional traumatic axonal injury. We found that the extent of reduction in the diffusion tensor imaging parameter relative anisotropy directly correlated with the number of amyloid precursor protein (APP)-stained axonal varicosities (r(2)=0.81, p<0.0001, n=20 injured mice). Interestingly, however, the least severe contusional injuries did not result in APP-stained axonal varicosities, but did cause reduction in relative anisotropy. Clearly, both the imaging assessments and the pathologic assessments will require iterative refinement. © 2015 Elsevier B.V. All rights reserved.

  14. Innovative multimodal DOTA/NODA nanoparticles for MRI and PET imaging for tumor detection

    International Nuclear Information System (INIS)

    Truillet, Charles; Bouziotis, Penelope; Tsoukalas, Charalambos; Sancey, Lucie; Denat, Franck; Boschetti, Frédéric; Stellas, Dimitris; Anagnostopoulos, Constantinos D; Koutoulidis, Vassilis; Moulopoulos, Lia A; Lux, François; Perriat, P; Tillement, Olivier

    2014-01-01

    The knowledge of the exact tumor stage is essential to adapt therapeutic strategies or to follow the evolution of the tumor after therapy in order to increase the survival chance. The multi-tasking diagnostics that combine techniques such as PET and MRI could really improve imaging tumor stage. PET mainly offers functional information about the disease with high sensitivity. MRI offers predominantly morphological information, able to provide an excellent soft tissue contrasts due to its high resolution.

  15. Innovative multimodal DOTA/NODA nanoparticles for MRI and PET imaging for tumor detection

    Energy Technology Data Exchange (ETDEWEB)

    Truillet, Charles [ILM, UMR 5306, University of Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France); Matériaux Ingénierie et Science, INSA Lyon, CNRS, University of Lyon, 69622 Villeurbanne (France); Bouziotis, Penelope; Tsoukalas, Charalambos [Radiochemistry Studies Laboratory, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Center for Scientific Research “Demokritos”, Athens (Greece); Sancey, Lucie [ILM, UMR 5306, University of Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France); Denat, Franck [Institut de Chimie Moléculaire de l’Université de Bourgogne, UMR CNRS 6302, University of Bourgogne, 21078 Dijon Cedex (France); Boschetti, Frédéric [CheMatech, 21000 Dijon (France); Stellas, Dimitris [Department of Cancer Biology, Biomedical Research Foundation, Academy of Athens, Athens (Greece); Anagnostopoulos, Constantinos D [Center for Experimental Surgery, Clinical and Translational Research, Biomedical Research Foundation, Academy of Athens, Athens (Greece); Koutoulidis, Vassilis; Moulopoulos, Lia A [Department of Radiology, University of Athens Medical School, Areteion Hospital, Athens (Greece); Lux, François [ILM, UMR 5306, University of Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France); Perriat, P [Matériaux Ingénierie et Science, INSA Lyon, CNRS, University of Lyon, 69622 Villeurbanne (France); Tillement, Olivier [ILM, UMR 5306, University of Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France)

    2014-07-29

    The knowledge of the exact tumor stage is essential to adapt therapeutic strategies or to follow the evolution of the tumor after therapy in order to increase the survival chance. The multi-tasking diagnostics that combine techniques such as PET and MRI could really improve imaging tumor stage. PET mainly offers functional information about the disease with high sensitivity. MRI offers predominantly morphological information, able to provide an excellent soft tissue contrasts due to its high resolution.

  16. Usefulness of magnetic resonance imaging (MRI) for patients with unilateral tinnitus

    Energy Technology Data Exchange (ETDEWEB)

    Katsura, Motoyasu [Sasebo Central Hospital, Nagasaki (Japan); Yoshida, Haruo; Kumagami, Hidetaka; Takahashi, Haruo [Nagasaki Univ. (Japan). Graduate School of Biomedical Sciences; Oosato, Yasuo [Sasebo City Hospital, Nagasaki (Japan); Dotsu, Mitsuru [National Nagasaki Medical Center, Omura (Japan)

    2004-06-01

    Audiography, X-ray (Stenvers view) and Magnetic Resonance Imaging (MRI) were performed on 88 patients exhibiting unilateral tinnitus. We diagnosed 4 cases (4.5%) of vestibular schwannoma and 41 cases (46.6%) of other abnormalities, including 2 cases of meningioma, 24 cases of old cerebral infarction, and 5 cases of mastoiditis. MRI was considered to be a first-line clinical examination for patients with unilateral tinnitus. (author)

  17. Usefulness of magnetic resonance imaging (MRI) for patients with unilateral tinnitus

    International Nuclear Information System (INIS)

    Katsura, Motoyasu; Yoshida, Haruo; Kumagami, Hidetaka; Takahashi, Haruo; Dotsu, Mitsuru

    2004-01-01

    Audiography, X-ray (Stenvers view) and Magnetic Resonance Imaging (MRI) were performed on 88 patients exhibiting unilateral tinnitus. We diagnosed 4 cases (4.5%) of vestibular schwannoma and 41 cases (46.6%) of other abnormalities, including 2 cases of meningioma, 24 cases of old cerebral infarction, and 5 cases of mastoiditis. MRI was considered to be a first-line clinical examination for patients with unilateral tinnitus. (author)

  18. Quantitative mass imaging of single biological macromolecules.

    Science.gov (United States)

    Young, Gavin; Hundt, Nikolas; Cole, Daniel; Fineberg, Adam; Andrecka, Joanna; Tyler, Andrew; Olerinyova, Anna; Ansari, Ayla; Marklund, Erik G; Collier, Miranda P; Chandler, Shane A; Tkachenko, Olga; Allen, Joel; Crispin, Max; Billington, Neil; Takagi, Yasuharu; Sellers, James R; Eichmann, Cédric; Selenko, Philipp; Frey, Lukas; Riek, Roland; Galpin, Martin R; Struwe, Weston B; Benesch, Justin L P; Kukura, Philipp

    2018-04-27

    The cellular processes underpinning life are orchestrated by proteins and their interactions. The associated structural and dynamic heterogeneity, despite being key to function, poses a fundamental challenge to existing analytical and structural methodologies. We used interferometric scattering microscopy to quantify the mass of single biomolecules in solution with 2% sequence mass accuracy, up to 19-kilodalton resolution, and 1-kilodalton precision. We resolved oligomeric distributions at high dynamic range, detected small-molecule binding, and mass-imaged proteins with associated lipids and sugars. These capabilities enabled us to characterize the molecular dynamics of processes as diverse as glycoprotein cross-linking, amyloidogenic protein aggregation, and actin polymerization. Interferometric scattering mass spectrometry allows spatiotemporally resolved measurement of a broad range of biomolecular interactions, one molecule at a time. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  19. The use of parallel imaging for MRI assessment of knees in children and adolescents.

    Science.gov (United States)

    Doria, Andrea S; Chaudry, Gulraiz A; Nasui, Cristina; Rayner, Tammy; Wang, Chenghua; Moineddin, Rahim; Babyn, Paul S; White, Larry M; Sussman, Marshall S

    2010-03-01

    Parallel imaging provides faster scanning at the cost of reduced signal-to-noise ratio (SNR) and increased artifacts. To compare the diagnostic performance of two parallel MRI protocols (PPs) for assessment of pathologic knees using an 8-channel knee coil (reference standard, conventional protocol [CP]) and to characterize the SNR losses associated with parallel imaging. Two radiologists blindly interpreted 1.5 Tesla knee MRI images in 21 children (mean 13 years, range 9-18 years) with clinical indications for an MRI scan. Sagittal proton density, T2-W fat-saturated FSE, axial T2-W fat-saturated FSE, and coronal T1-W (NEX of 1,1,1) images were obtained with both CP and PP. Images were read for soft tissue and osteochondral findings. There was a 75% decrease in acquisition time using PP in comparison to CP. The CP and PP protocols fell within excellent or upper limits of substantial agreement: CP, kappa coefficient, 0.81 (95% CIs, 0.73-0.89); PP, 0.80-0.81 (0.73-0.89). The sensitivity of the two PPs was similar for assessment of soft (0.98-1.00) and osteochondral (0.89-0.94) tissues. Phantom data indicated an SNR of 1.67, 1.6, and 1.51 (axial, sagittal and coronal planes) between CP and PP scans. Parallel MRI provides a reliable assessment for pediatric knees in a significantly reduced scan time without affecting the diagnostic performance of MRI.

  20. 3D T2-weighted imaging to shorten multiparametric prostate MRI protocols.

    Science.gov (United States)

    Polanec, Stephan H; Lazar, Mathias; Wengert, Georg J; Bickel, Hubert; Spick, Claudio; Susani, Martin; Shariat, Shahrokh; Clauser, Paola; Baltzer, Pascal A T

    2018-04-01

    To determine whether 3D acquisitions provide equivalent image quality, lesion delineation quality and PI-RADS v2 performance compared to 2D acquisitions in T2-weighted imaging of the prostate at 3 T. This IRB-approved, prospective study included 150 consecutive patients (mean age 63.7 years, 35-84 years; mean PSA 7.2 ng/ml, 0.4-31.1 ng/ml). Two uroradiologists (R1, R2) independently rated image quality and lesion delineation quality using a five-point ordinal scale and assigned a PI-RADS score for 2D and 3D T2-weighted image data sets. Data were compared using visual grading characteristics (VGC) and receiver operating characteristics (ROC)/area under the curve (AUC) analysis. Image quality was similarly good to excellent for 2D T2w (mean score R1, 4.3 ± 0.81; R2, 4.7 ± 0.83) and 3D T2w (mean score R1, 4.3 ± 0.82; R2, 4.7 ± 0.69), p = 0.269. Lesion delineation was rated good to excellent for 2D (mean score R1, 4.16 ± 0.81; R2, 4.19 ± 0.92) and 3D T2w (R1, 4.19 ± 0.94; R2, 4.27 ± 0.94) without significant differences (p = 0.785). ROC analysis showed an equivalent performance for 2D (AUC 0.580-0.623) and 3D (AUC 0.576-0.629) T2w (p > 0.05, respectively). Three-dimensional acquisitions demonstrated equivalent image and lesion delineation quality, and PI-RADS v2 performance, compared to 2D in T2-weighted imaging of the prostate. Three-dimensional T2-weighted imaging could be used to considerably shorten prostate MRI protocols in clinical practice. • 3D shows equivalent image quality and lesion delineation compared to 2D T2w. • 3D T2w and 2D T2w image acquisition demonstrated comparable diagnostic performance. • Using a single 3D T2w acquisition may shorten the protocol by 40%. • Combined with short DCE, multiparametric protocols of 10 min are feasible.

  1. Imaging transplanted stem cells in real time using an MRI dual-contrast method

    Science.gov (United States)

    Ngen, Ethel J.; Wang, Lee; Kato, Yoshinori; Krishnamachary, Balaji; Zhu, Wenlian; Gandhi, Nishant; Smith, Barbara; Armour, Michael; Wong, John; Gabrielson, Kathleen; Artemov, Dmitri

    2015-01-01

    Stem cell therapies are currently being investigated for the repair of brain injuries. Although exogenous stem cell labelling with superparamagnetic iron oxide nanoparticles (SPIONs) prior to transplantation provides a means to noninvasively monitor stem cell transplantation by magnetic resonance imaging (MRI), monitoring cell death is still a challenge. Here, we investigate the feasibility of using an MRI dual-contrast technique to detect cell delivery, cell migration and cell death after stem cell transplantation. Human mesenchymal stem cells were dual labelled with SPIONs and gadolinium-based chelates (GdDTPA). The viability, proliferation rate, and differentiation potential of the labelled cells were then evaluated. The feasibility of this MRI technique to distinguish between live and dead cells was next evaluated using MRI phantoms, and in vivo using both immune-competent and immune-deficient mice, following the induction of brain injury in the mice. All results were validated with bioluminescence imaging. In live cells, a negative (T2/T2*) MRI contrast predominates, and is used to track cell delivery and cell migration. Upon cell death, a diffused positive (T1) MRI contrast is generated in the vicinity of the dead cells, and serves as an imaging marker for cell death. Ultimately, this technique could be used to manage stem cell therapies. PMID:26330231

  2. Magnetic resonance imaging goes postmortem: noninvasive detection and assessment of myocardial infarction by postmortem MRI

    International Nuclear Information System (INIS)

    Jackowski, Christian; Warntjes, Marcel J.B.; Persson, Anders; Berge, Johan; Baer, Walter

    2011-01-01

    To investigate the performance of postmortem magnetic resonance imaging (pmMRI) in identification and characterization of lethal myocardial infarction in a non-invasive manner on human corpses. Before forensic autopsy, 20 human forensic corpses were examined on a 1.5-T system for the presence of myocardial infarction. Short axis, transversal and longitudinal long axis images (T1-weighted; T2-weighted; PD-weighted) were acquired in situ. In subsequent autopsy, the section technique was adapted to short axis images. Histological investigations were conducted to confirm autopsy and/or radiological diagnoses. Nineteen myocardial lesions were detected and age staged with pmMRI, of which 13 were histologically confirmed (chronic, subacute and acute). Six lesions interpreted as peracute by pmMRI showed no macroscopic or histological finding. Five of the six peracute lesions correlated well to coronary pathology, and one case displayed a severe hypertrophic alteration. pmMRI reliably demonstrates chronic, subacute and acute myocardial infarction in situ. In peracute cases pmMRI may display ischemic lesions undetectable at autopsy and routine histology. pmMRI has the potential to substantiate autopsy and to counteract the loss of reliable information on causes of death due to the recent disappearance of the clinical autopsy. (orig.)

  3. MRI contrast agent for molecular imaging of the HER2/neu receptor using targeted magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rasaneh, Samira; Rajabi, Hossein, E-mail: hrajabi@modares.ac.ir [Tarbiat Modares University, Department of Medical Physics (Iran, Islamic Republic of); Babaei, Mohammad Hossein [Nuclear Science and Technology Research Institute, Department of Radioisotope (Iran, Islamic Republic of); Akhlaghpoor, Shahram [Sina Hospital, Tehran Medical University, Noor Medical Imaging Center (Iran, Islamic Republic of)

    2011-06-15

    In this study, Trastuzumab modified Magnetic Nanoparticles (TMNs) were prepared as a new contrast agent for detecting HER2 (Human epidermal growth factor receptor-2) expression tumors by magnetic resonance imaging (MRI). TMNs were prepared based on iron oxide nanoparticles core and Trastuzumab modified dextran coating. The TMNs core and hydrodynamic size were determined by transmission electron microscopy and dynamic light scattering. TMNs stability and cytotoxicity were investigated. The ability of TMNs for HER2 detection were evaluated in breast carcinoma cell lines (SKBr3 and MCF7 cells) and tumor-bearing mice by MRI and iron uptake determination. The particles core and hydrodynamic size were 9 {+-} 2.5 and 41 {+-} 15 nm (size range: 15-87 nm), respectively. The molar antibody/nanoparticle ratio was 3.1-3.5. TMNs were non-toxic to the cells below the 30 {mu}g (Fe)/mL concentration and good stable up to 8 weeks in PBS buffer. TMNs could detect HER2 oncogenes in the cells surface with imagable contrast by MRI. The invivo study in mice bearing tumors indicated that TMNs possessed a good diagnostic ability as HER2 specific contrast agent by MRI. TMNs were demonstrated to be able to selectively accumulate in the tumor cells, with a proper signal enhancement in MRI T2 images. So, the complex may be considered for further investigations as an MRI contrast agent for detection of HER2 expression tumors in human.

  4. Diagnostic imaging in 13 cases of Rasmussen's encephalitis. Can early MRI suggest the diagnosis?

    Energy Technology Data Exchange (ETDEWEB)

    Chiapparini, L.; Farina, L.; Ciceri, E.; Erbetta, A.; Savoiardo, M. [Dept. of Neuroradiology, Ist. Nazionale Neurologico ' ' C. Besta' ' , Milano (Italy); Granata, T.; Ragona, F.; Freri, E. [Dept. of Paediatric Neurology, Ist. Nazionale Neurologico ' ' C. Besta' ' , Milano (Italy); Fusco, L. [Dept. of Paediatric Neurology, Ospedale Pediatrico Bambino Gesu, Roma (Italy); Gobbi, G. [Dept. of Paediatric Neurology, Ospedale Maggiore Pizzardi, Bologna (Italy); Capovilla, G. [Dept. of Paediatric Neurology, Ospedale Poma, Mantova (Italy); Tassi, L. [Dept. of Epilepsy Surgery, Ospedale Niguarda Ca' Granda, Milano (Italy); Viri, M. [Epilepsy Centre, Ospedale Fatebenefratelli-Oftalmico, Milano (Italy); Giordano, L. [Dept. of Paediatric Neurology, Ospedale Civile, Brescia (Italy); Bernardina, B.D. [Dept. of Paediatric Neurology, Policlinico Borgo Roma, Verona (Italy); Spreafico, R. [Dept. of Neurophysiology, Ist. Nazionale Neurologico ' ' C. Besta' ' , Milano (Italy)

    2003-03-01

    Rasmussen's encephalitis (RE) is a rare, progressive, chronic encephalitis characterised by drug-resistant epilepsy, progressive hemiparesis and mental impairment. It typically involves only one cerebral hemisphere, which becomes atrophic. We present neuroradiological findings in 13 children with RE. MRI was performed in all patients, fluorodeoxyglucose positron-emission tomography (PET) in three, Tc-99m hexamethylpropylenamine oxime single-photon emission computed tomography (SPECT) in two and proton MR spectroscopy ({sup 1}HMRS) in two. MRI showed progression of the hemisphere atrophy, always prevalent in the region primarily involved (13 patients), spread of the abnormal signal in white matter (11) and cortex (10) and progression of atrophy of the head of the caudate nucleus (nine). Associated secondary changes were: atrophy of the contralateral cerebellar hemisphere (in four patients), the ipsilateral hippocampus (in five) and the brain stem (in five). The earliest CT and MRI abnormalities, seen between 1 day and 4 months after the first seizure (in 12 patients examined, nine of whom had MRI) in one cerebral hemisphere included: high signal on T2-weighted images in the cortex (seven patients) and white matter (nine), cortical atrophy usually involving the frontoinsular region, with mild or severe enlargement of the lateral ventricle (eight) and moderate atrophy of the head of the caudate nucleus (seven). (orig.)

  5. Quantitative estimation of brain atrophy and function with PET and MRI two-dimensional projection images

    International Nuclear Information System (INIS)

    Saito, Reiko; Uemura, Koji; Uchiyama, Akihiko; Toyama, Hinako; Ishii, Kenji; Senda, Michio

    2001-01-01

    The purpose of this paper is to estimate the extent of atrophy and the decline in brain function objectively and quantitatively. Two-dimensional (2D) projection images of three-dimensional (3D) transaxial images of positron emission tomography (PET) and magnetic resonance imaging (MRI) were made by means of the Mollweide method which keeps the area of the brain surface. A correlation image was generated between 2D projection images of MRI and cerebral blood flow (CBF) or 18 F-fluorodeoxyglucose (FDG) PET images and the sulcus was extracted from the correlation image clustered by K-means method. Furthermore, the extent of atrophy was evaluated from the extracted sulcus on 2D-projection MRI and the cerebral cortical function such as blood flow or glucose metabolic rate was assessed in the cortex excluding sulcus on 2D-projection PET image, and then the relationship between the cerebral atrophy and function was evaluated. This method was applied to the two groups, the young and the aged normal subjects, and the relationship between the age and the rate of atrophy or the cerebral blood flow was investigated. This method was also applied to FDG-PET and MRI studies in the normal controls and in patients with corticobasal degeneration. The mean rate of atrophy in the aged group was found to be higher than that in the young. The mean value and the variance of the cerebral blood flow for the young are greater than those of the aged. The sulci were similarly extracted using either CBF or FDG PET images. The purposed method using 2-D projection images of MRI and PET is clinically useful for quantitative assessment of atrophic change and functional disorder of cerebral cortex. (author)

  6. TU-G-BRA-08: BEST IN PHYSICS (JOINT IMAGING-THERAPY): Hybrid PET-MRI Imaging of Acute Radiation Induced Cardiac Toxicity

    International Nuclear Information System (INIS)

    El-Sherif, O; Xhaferllari, I; Gaede, S; Sykes, J; Butler, J; Wisenberg, G; Prato, F

    2015-01-01

    Purpose: To identify the presence of low-dose radiation induced cardiac toxicity in a canine model using hybrid positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: Research ethics board approval was obtained for a longitudinal imaging study of 5 canines after cardiac irradiation. Animals were imaged at baseline, 1 week post cardiac irradiation, and 1 month post cardiac irradiation using a hybrid PET- MRI system (Biograph mMR, Siemens Healthcare). The imaging protocol was designed to assess acute changes in myocardial perfusion and inflammation. Myocardial perfusion imaging was performed using N13-ammonia tracer followed by a dynamic PET acquisition scan. A compartmental tracer kinetic model was used for absolute perfusion quantification. Myocardial inflammation imaging was performed using F18-fluorodeoxyglucose (FDG) tracer. The standard uptake value (SUV) over a region encompassing the whole heart was used to compare FDG scans. All animals received a simulation CT scan (GE Medical Systems) for radiation treatment planning. Radiation treatment plans were created using the Pinncale3 treatment planning system (Philips Radiation Oncology Systems) and designed to resemble the typical cardiac exposure during left-sided breast cancer radiotherapy. Cardiac irradiations were performed in a single fraction using a TrueBeam linear accelerator (Varian Medical Systems). Results: The delivered dose (mean ± standard deviation) to heart was 1.8±0.2 Gy. Reductions in myocardial stress perfusion relative to baseline were observed in 2 of the 5 animals 1 month post radiation. A global inflammatory response 1 month post radiation was observed in 4 of the 5 animals. The calculated SUV at 1 month post radiation was significantly higher (p=0.05) than the baseline SUV. Conclusion: Low doses of cardiac irradiation (< 2 Gy) may lead to myocardial perfusion defects and a global inflammatory response that can be detectable as early as 1 month post irradiation

  7. TU-G-BRA-08: BEST IN PHYSICS (JOINT IMAGING-THERAPY): Hybrid PET-MRI Imaging of Acute Radiation Induced Cardiac Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    El-Sherif, O; Xhaferllari, I; Gaede, S [Western Univeristy, London, ON (United Kingdom); London Regional Cancer Program, London, ON (United Kingdom); Sykes, J; Butler, J [Lawson Health Research Institute, London, ON (United Kingdom); Wisenberg, G; Prato, F [Western Univeristy, London, ON (United Kingdom); Lawson Health Research Institute, London, ON (United Kingdom)

    2015-06-15

    Purpose: To identify the presence of low-dose radiation induced cardiac toxicity in a canine model using hybrid positron emission tomography (PET) and magnetic resonance imaging (MRI). Methods: Research ethics board approval was obtained for a longitudinal imaging study of 5 canines after cardiac irradiation. Animals were imaged at baseline, 1 week post cardiac irradiation, and 1 month post cardiac irradiation using a hybrid PET- MRI system (Biograph mMR, Siemens Healthcare). The imaging protocol was designed to assess acute changes in myocardial perfusion and inflammation. Myocardial perfusion imaging was performed using N13-ammonia tracer followed by a dynamic PET acquisition scan. A compartmental tracer kinetic model was used for absolute perfusion quantification. Myocardial inflammation imaging was performed using F18-fluorodeoxyglucose (FDG) tracer. The standard uptake value (SUV) over a region encompassing the whole heart was used to compare FDG scans. All animals received a simulation CT scan (GE Medical Systems) for radiation treatment planning. Radiation treatment plans were created using the Pinncale3 treatment planning system (Philips Radiation Oncology Systems) and designed to resemble the typical cardiac exposure during left-sided breast cancer radiotherapy. Cardiac irradiations were performed in a single fraction using a TrueBeam linear accelerator (Varian Medical Systems). Results: The delivered dose (mean ± standard deviation) to heart was 1.8±0.2 Gy. Reductions in myocardial stress perfusion relative to baseline were observed in 2 of the 5 animals 1 month post radiation. A global inflammatory response 1 month post radiation was observed in 4 of the 5 animals. The calculated SUV at 1 month post radiation was significantly higher (p=0.05) than the baseline SUV. Conclusion: Low doses of cardiac irradiation (< 2 Gy) may lead to myocardial perfusion defects and a global inflammatory response that can be detectable as early as 1 month post irradiation

  8. Use of dynamic images in radiology education: Movies of CT and MRI in the anatomy classroom.

    Science.gov (United States)

    Jang, Hye Won; Oh, Chang-Seok; Choe, Yeon Hyeon; Jang, Dong Su

    2018-04-19

    Radiology education is a key component in many preclinical anatomy courses. However, the reported effectiveness of radiology education within such anatomy classrooms has varied. This study was conducted to determine if a novel educational method using dynamic images of movies of computed tomography (CT) and magnetic resonance imaging (MRI) was effective in radiology education during a preclinical anatomy course, aided by clay modeling, specific hand gestures (digit anatomy), and reports from dissection findings uploaded to the anatomy course website (digital reports). Feedback surveys using a five-point Likert scale were administered to better clarify students' opinions regarding their understanding of CT and MRI of anatomical structures, as well as to determine if such preclinical radiology education was helpful in their clinical studies. After completion of the anatomy course taught with dynamic images of CT and MRI, most students demonstrated an adequate understanding of basic CT and MR images. Additionally, students in later clinical years generally believed that their study of radiologic images during the preclinical anatomy course was helpful for their clinical studies and clerkship rotations. Moreover, student scores on imaging anatomy examinations demonstrated meaningful improvements in performance after using dynamic images from movies of CT and MRI. Anat Sci Educ. © 2018 American Association of Anatomists. © 2018 American Association of Anatomists.

  9. The evaluation of FDG-PET imaging for epileptogenic focus localization in patients with MRI positive and MRI negative temporal lobe epilepsy

    International Nuclear Information System (INIS)

    Gok, Beril; Jallo, George; Hayeri, Reza; Wahl, Richard; Aygun, Nafi

    2013-01-01

    We studied the contribution of interictal FDG-PET ([18 F] fluorodeoxyglucose-positron emission tomography) in epileptic focus identification in temporal lobe epilepsy patients with positive, equivocal and negative magnetic resonance imaging (MRI). Ninety-eight patients who underwent surgical treatment for drug resistant temporal lobe epilepsy after neuropsychological evaluation, scalp video EEG monitoring, FDG-PET, MRI and/or long-term intracranial EEG and with >12 months clinical follow-up were included in this study. FDG-PET findings were compared to MRI, histopathology, scalp video EEG and long-term intracranial EEG monitoring. FDG-PET lateralized the seizure focus in 95 % of MRI positive, 69 % of MRI equivocal and 84 % of MRI negative patients. There was no statistically significant difference between the surgical outcomes among the groups with Engel class I and II outcomes achieved in 86 %, 86 %, 84 % of MRI positive, equivocal and negative temporal lobe epilepsy patients, respectively. The patients with positive unilateral FDG-PET demonstrated excellent postsurgical outcomes, with 96 % Engel class I and II. Histopathology revealed focal lesions in 75 % of MRI equivocal, 84 % of MRI positive, and 23 % of MRI negative temporal lobe epilepsy cases. FDG-PET is an accurate noninvasive method in lateralizing the epileptogenic focus in temporal lobe epilepsy, especially in patients with normal or equivocal MRIs, or non-lateralized EEG monitoring. Very subtle findings in MRI are often associated with histopathological lesions and should be described in MRI reports. The patients with negative or equivocal MRI temporal lobe epilepsy are good surgical candidates with comparable postsurgical outcomes to patients with MRI positive temporal lobe epilepsy. (orig.)

  10. The evaluation of FDG-PET imaging for epileptogenic focus localization in patients with MRI positive and MRI negative temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Gok, Beril [Drexel University, Department of Radiology, Mercy Catholic Medical Center, Philadelphia, PA (United States); Johns Hopkins University, Division of Nuclear Medicine, Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Jallo, George [Johns Hopkins University, Department of Neurosurgery, Baltimore, MD (United States); Hayeri, Reza [Drexel University, Department of Radiology, Mercy Catholic Medical Center, Philadelphia, PA (United States); Wahl, Richard [Johns Hopkins University, Division of Nuclear Medicine, Department of Radiology and Radiological Sciences, Baltimore, MD (United States); Aygun, Nafi [Johns Hopkins University, Division of Neuroradiology, Department of Radiology and Radiological Sciences, Baltimore, MD (United States)

    2013-05-15

    We studied the contribution of interictal FDG-PET ([18 F] fluorodeoxyglucose-positron emission tomography) in epileptic focus identification in temporal lobe epilepsy patients with positive, equivocal and negative magnetic resonance imaging (MRI). Ninety-eight patients who underwent surgical treatment for drug resistant temporal lobe epilepsy after neuropsychological evaluation, scalp video EEG monitoring, FDG-PET, MRI and/or long-term intracranial EEG and with >12 months clinical follow-up were included in this study. FDG-PET findings were compared to MRI, histopathology, scalp video EEG and long-term intracranial EEG monitoring. FDG-PET lateralized the seizure focus in 95 % of MRI positive, 69 % of MRI equivocal and 84 % of MRI negative patients. There was no statistically significant difference between the surgical outcomes among the groups with Engel class I and II outcomes achieved in 86 %, 86 %, 84 % of MRI positive, equivocal and negative temporal lobe epilepsy patients, respectively. The patients with positive unilateral FDG-PET demonstrated excellent postsurgical outcomes, with 96 % Engel class I and II. Histopathology revealed focal lesions in 75 % of MRI equivocal, 84 % of MRI positive, and 23 % of MRI negative temporal lobe epilepsy cases. FDG-PET is an accurate noninvasive method in lateralizing the epileptogenic focus in temporal lobe epilepsy, especially in patients with normal or equivocal MRIs, or non-lateralized EEG monitoring. Very subtle findings in MRI are often associated with histopathological lesions and should be described in MRI reports. The patients with negative or equivocal MRI temporal lobe epilepsy are good surgical candidates with comparable postsurgical outcomes to patients with MRI positive temporal lobe epilepsy. (orig.)

  11. Dynamic MRI of the liver with parallel acquisition technique. Characterization of focal liver lesions and analysis of the hepatic vasculature in a single MRI session

    International Nuclear Information System (INIS)

    Heilmaier, C.; Sutter, R.; Lutz, A.M.; Willmann, J.K.; Seifert, B.

    2008-01-01

    Purpose: to retrospectively evaluate the performance of breath-hold contrast-enhanced 3D dynamic parallel gradient echo MRI (pMRT) for the characterization of focal liver lesions (standard of reference: histology) and for the analysis of hepatic vasculature (standard of reference: contrast-enhanced 64-detector row computed tomography; MSCT) in a single MRI session. Materials and method: two blinded readers independently analyzed preoperative pMRT data sets (1.5T-MRT) of 45 patients (23 men, 22 women; 28 - 77 years, average age, 48 years) with a total of 68 focal liver lesions with regard to image quality of hepatic arteries, portal and hepatic veins, presence of variant anatomy of the hepatic vasculature, as well as presence of portal vein thrombosis and hemodynamically significant arterial stenosis. In addition, both readers were asked to identify and characterize focal liver lesions. Imaging parameters of pMRT were: TR/TE/matrix/slice thickness/acquisition time: 3.1 ms/1.4 ms/384 x 224/4 mm/15 - 17 s. MSCT was performed with a pitch of 1.2, an effective slice thickness of 1 mm and a matrix of 512 x 512. Results: based on histology, the 68 liver lesions were found to be 42 hepatocellular carcinomas (HCC), 20 metastases, 3 cholangiocellular carcinomas (CCC) as well as 1 dysplastic nodule, 1 focal nodular hyperplasia (FNH) and 1 atypical hemangioma. Overall, the diagnostic accuracy was high for both readers (91 - 100%) in the characterization of these focal liver lesions with an excellent interobserver agreement (κ-values of 0.89 [metastases], 0.97 [HCC] and 1 [CCC]). On average, the image quality of all vessels under consideration was rated good or excellent in 89% (reader 1) and 90% (reader 2). Anatomical variants of the hepatic arteries, hepatic veins and portal vein as well as thrombosis of the portal vein were reliably detected by pMRT. Significant arterial stenosis was found with a sensitivity between 86% and 100% and an excellent interobserver agreement (κ

  12. Studies on improvement of diagnosis of neurosurgical lesions by magnetic resonance imaging (MRI), 2

    International Nuclear Information System (INIS)

    Shimizu, Kotoyuki

    1989-01-01

    Findings of magnetic resonance (MRI) imaging in 46 patients with sellar or parasellar mass were reviewed and compared with those of concurrently available X-ray CT. Intrasellar contents, the hypothalamic pituitary region, adjacent brain stem, optic nerves, and the surrounding cerebrospinal fluid were clearly depicted on T1-weighted images. The cavernous sinus and blood vessels, including the Willis circle, were visualized on T2-weighted images. In detecting pituitary macroadenoma, MRI seemed to be the most userful modality, because it was superior to CT in identifying abnormal changes of the infundibulum, diaphragma sellae, cavernous sinus and optic chiasm. Macroadenoma of the pituitary gland was usually isointense to the normal cerebral cortex on T1- and T2-weighted images. T1- and T2-weighted relaxation times for pituitary adenoma were slightly prolonged. The normal pituitary gland was distinguishable from adenomatous tissues. For microadenoma, MRI failed to show lesions or erosion of the sellar floor. Craniopharyngioma, meningioma of the tuberculum sellae, hypothalamic tumor, such as glioma and germinoma, and the other parasellar masses were clearly visualized on MRI. MRI was superior to CT in detecting tumor and its involvement, but inferior in detecting presence of calcification. T1-weighted imaging was useful in identifing the presence of intratumoral hemorrhage. Cysts of craniopharyngioma had various appearances on T1-weighted images. High signal cyst intensity corresponded to a high cholesterol content or the presence of methemoglobin. MRI depicted empty sella. The intrasellar content had the same appearance as that of the cerebrospinal fluid space, and the flattened pituitary gland and pituitary stalk were detected on T1-weighted images. (N.K.)

  13. Dual-Modal Nanoprobes for Imaging of Mesenchymal Stem Cell Transplant by MRI and Fluorescence Imaging

    International Nuclear Information System (INIS)

    Sung, Chang Kyu; Hong, Kyung Ah; Lin, Shun Mei

    2009-01-01

    To determine the feasibility of labeling human mesenchymal stem cells (hMSCs) with bifunctional nanoparticles and assessing their potential as imaging probes in the monitoring of hMSC transplantation. The T1 and T2 relaxivities of the nanoparticles (MNP SiO 2 [RITC]-PEG) were measured at 1.5T and 3T magnetic resonance scanner. Using hMSCs and the nanoparticles, labeling efficiency, toxicity, and proliferation were assessed. Confocal laser scanning microscopy and transmission electron microscopy were used to specify the intracellular localization of the endocytosed iron nanoparticles. We also observed in vitro and in vivo visualization of the labeled hMSCs with a 3T MR scanner and optical imaging. MNP SiO 2 (RITC)-PEG showed both superparamagnetic and fluorescent properties. The r 1 and r 2 relaxivity values of the MNP SiO 2 (RITC)-PEG were 0.33 and 398 mM -1 s -1 at 1.5T, respectively, and 0.29 and 453 mM -1 s -1 at 3T, respectively. The effective internalization of MNP SiO 2 (RITC)-PEG into hMSCs was observed by confocal laser scanning fluorescence microscopy. The transmission electron microscopy images showed that MNP SiO 2 (RITC)-PEG was internalized into the cells and mainly resided in the cytoplasm. The viability and proliferation of MNP SiO 2 (RITC)-PEG-labeled hMSCs were not significantly different from the control cells. MNP SiO 2 (RITC)-PEG-labeled hMSCs were observed in vitro and in vivo with optical and MR imaging. MNP SiO 2 (RITC)-PEG can be a useful contrast agent for stem cell imaging, which is suitable for a bimodal detection by MRI and optical imaging

  14. Molecular imaging of atherosclerosis in mice with MRI and near-infrared fluorescence imaging

    International Nuclear Information System (INIS)

    Lu Tong; Wen Song; Zhou Guanhui; Ju Shenghong; Teng Gaojun

    2012-01-01

    Objective: To explore the feasibility of detecting atherosclerotic plaques with 7.0 T MRI and near-infrared fluorescence imaging (NIRF) using molecular imaging probes. Methods: Atherosclerotic plaques were established in male atherosclerotic apolipoprotein E knockout (ApoE-/-) mice fed with high-cholesterol diet for 20 weeks. Wild-type C57BL/6 mice were used as negative controls. 7.0 T MRI was performed before and 36 h after intravenously administration of ultrasmall superparamagnetic particle of iron oxide (USPIO). NIR 797 was conjugated with anti-mouse-oxidized modified low density lipoprotein (oxLDL) antibodies to construct an anti-oxLDL-Ab-NIR 797 probe while non-specific IgG-NIR 797 and PBS used as controls. NIRF was performed 24 h after tail vein injection of the probe. Independent sample t-test and one-way analysis of variance were used to analyze the data by SPSS 17.0. Results: In APOE-/-mice, in vivo 36 h post-USPIO T 2 WI images revealed strong focal signal loss in the abdominal aorta than that of pre-USPIO, with relative signal intensity 0.70 ± 0.04 and 1.28 ± 0.06, respectively (t=3.376, P<0.05). The percent of signal reduced was (-56.58 ± 4.25)%. The Prussian blue staining confirmed the depositions of iron particles in the plaque lesions. Significant fluorochrome accumulation in atherosclerotic plaques was demonstrated in aortic root, aortic arch and the starting of descending aorta 24 h after injection of the anti-oxLDL-Ab-NIR 797 probe. Minimal antibody uptake was observed in normal vessels from wild-type mice receiving the anti-oxLDL-Ab-NIR 797 (SNR: 2.29 ± 1.11) and in atherosclerotic vessels from ApoE-/- mice receiving the non-specific IgG-NIR 797 (19.58 ±3.06) or PBS (4.19 ±0.82), which was significantly different from the uptake of anti-oxLDL-Ab-NIR 797 group (42.51 ±5.24, F=25.104, P<0.05). Comparison between oil red O staining and NIRF 24 h after injection of NIR 797 labeled oxLDL-antibody revealed a significant correlation (r=0.738, P

  15. Stereotactic imaging for radiotherapy: accuracy of CT, MRI, PET and SPECT

    International Nuclear Information System (INIS)

    Karger, Christian P; Hipp, Peter; Henze, Marcus; Echner, Gernot; Hoess, Angelika; Schad, Lothar; Hartmann, Guenther H

    2003-01-01

    CT, MRI, PET and SPECT provide complementary information for treatment planning in stereotactic radiotherapy. Stereotactic correlation of these images requires commissioning tests to confirm the localization accuracy of each modality. A phantom was developed to measure the accuracy of stereotactic localization for CT, MRI, PET and SPECT in the head and neck region. To this end, the stereotactically measured coordinates of structures within the phantom were compared with their mechanically defined coordinates. For MRI, PET and SPECT, measurements were performed using two different devices. For MRI, T1- and T2-weighted imaging sequences were applied. For each measurement, the mean radial deviation in space between the stereotactically measured and mechanically defined position of target points was determined. For CT, the mean radial deviation was 0.4 ± 0.2 mm. For MRI, the mean deviations ranged between 0.7 ± 0.2 mm and 1.4 ± 0.5 mm, depending on the MRI device and the imaging sequence. For PET, mean deviations of 1.1 ± 0.5 mm and 2.4 ± 0.3 mm were obtained. The mean deviations for SPECT were 1.6 ± 0.5 mm and 2.0 ± 0.6 mm. The phantom is well suited to determine the accuracy of stereotactic localization with CT, MRI, PET and SPECT in the head and neck region. The obtained accuracy is well below the physical resolution for CT, PET and SPECT, and of comparable magnitude for MRI. Since the localization accuracy may be device dependent, results obtained at one device cannot be generalized to others

  16. Single molecule image formation, reconstruction and processing: introduction.

    Science.gov (United States)

    Ashok, Amit; Piestun, Rafael; Stallinga, Sjoerd

    2016-07-01

    The ability to image at the single molecule scale has revolutionized research in molecular biology. This feature issue presents a collection of articles that provides new insights into the fundamental limits of single molecule imaging and reports novel techniques for image formation and analysis.

  17. Abnormal findings of magnetic resonance imaging (MRI) in patients with systemic lupus erythematosus involving the brain

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Akira; Okada, Jun; Kondo, Hirobumi (Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Medicine); Kashiwazaki, Sadao

    1992-06-01

    To elucidate the clinical significance of MRI on central nervous system systemic lupus erythematosus (CNS-SLE), MRI and CT scans were performed in 35 patients with SLE, of 18 patients who had CNS manifestations at the time of MRI examinations. The investigations were also carried out in 17 patients without CNS-SLE. The rate of detection of abnormal findings on MRI in patients with CNS-SLE was 77.2% (14/18), which was high, as compared with the rate of those on CT scans (50%: 9/18). Especially, all of 4 patients with seizure and 3 patients with encephalopathy showed abnormal MRI findings, although respectively 50% and 33.3% of them had abnormal CT scan findings. MRI findings were classified into 4 groups below: (1) Large focal are as increased signal intensity at T2 weighted image. These were observed in 2 of 4 patients with seizure and 1 of 3 patients with encephalopathy, which were completely resolved after treatment. (2) Patchy subcortical foci of increased signal intensity at T2 weighted image. These were observed in 11 of 18 CNS-SLE and 7 of 17 without CNS-SLE, which were not detected by CT scan. (3) All of six patients with cerebral infarctions showed high signal intensity areas at T2 weighted image and low signal intensity areas at T1 weighted image. (4) Normal findings were observed in 4 of 18 CNS-SLE (22.2%). We concluded that MRI is useful for the evaluation of CNS-SLE and provides more information than CT scan. (author).

  18. Abnormal findings of magnetic resonance imaging (MRI) in patients with systemic lupus erythematosus involving the brain

    International Nuclear Information System (INIS)

    Ishikawa, Akira; Okada, Jun; Kondo, Hirobumi; Kashiwazaki, Sadao.

    1992-01-01

    To elucidate the clinical significance of MRI on central nervous system systemic lupus erythematosus (CNS-SLE), MRI and CT scans were performed in 35 patients with SLE, of 18 patients who had CNS manifestations at the time of MRI examinations. The investigations were also carried out in 17 patients without CNS-SLE. The rate of detection of abnormal findings on MRI in patients with CNS-SLE was 77.2% (14/18), which was high, as compared with the rate of those on CT scans (50%: 9/18). Especially, all of 4 patients with seizure and 3 patients with encephalopathy showed abnormal MRI findings, although respectively 50% and 33.3% of them had abnormal CT scan findings. MRI findings were classified into 4 groups below: 1) Large focal are as increased signal intensity at T2 weighted image. These were observed in 2 of 4 patients with seizure and 1 of 3 patients with encephalopathy, which were completely resolved after treatment. 2) Patchy subcortical foci of increased signal intensity at T2 weighted image. These were observed in 11 of 18 CNS-SLE and 7 of 17 without CNS-SLE, which were not detected by CT scan. 3) All of six patients with cerebral infarctions showed high signal intensity areas at T2 weighted image and low signal intensity areas at T1 weighted image. 4) Normal findings were observed in 4 of 18 CNS-SLE (22.2%). We concluded that MRI is useful for the evaluation of CNS-SLE and provides more information than CT scan. (author)

  19. Imaging of the myocardium using {sup 18}F-FDG-PET/MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ferda, Jiří, E-mail: ferda@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Hromádka, Milan, E-mail: hromadkam@fnplzen.cz [Department of Cardiology, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic); Baxa, Jan, E-mail: baxaj@fnplzen.cz [Clinic of the Imaging Methods, University Hospital Plzen, Alej Svobody 80, 304 60 Plzeň (Czech Republic)

    2016-10-15

    Highlights: • The natural combination of the metabolic and structural information is the most important strenghtof myocardial PET/MRI. • Metabolic conversion to glycolysis is needed in the assesment ov the viable myocardium. • Metabolic conversion to the fatty acid metabolism is the crucial in the assesment of the ischemic memory and myocardial inflammation. - Abstract: The introduction of the integrated hybrid PET/MRI equipment creates the possibility to perform PET and MRI simultaneously. Depending on the clinical question, the metabolic conversion to glycolytic activity or beta-oxidation is performed before the application of FDG. Since FDG aids to evaluate the energetic metabolism of the myocytes and myocardial MRI reaches the imaging capabilities of perfusion and tissue characterization in the daily routine, FDG-PET/MRI looks to be a promising method of PET/MRI exploitation in cardiac imaging. When myocardial FDG uptake should be evaluated in association with the perfusion distribution, the cross-evaluation of FDG accumulation distribution and perfusion distribution pattern is necessary. The different scenarios may be used in the assessment of myocardium, the conversion to glycolytic activity is used in the imaging of the viable myocardium, but the glycolytic activity suppression might be used in the indications of the identification of injured myocardium by ischemia or inflammation. FDG-PET/MRI might aid to answer the clinical tasks according to the structure, current function and possibilities to improve the function in ischemic heart disease or to display the extent or activity of myocardial inflammation in sarcoidosis. The tight coupling between metabolism, perfusion and contractile function offers an opportunity for the simultaneous assessment of cardiac performance using one imaging modality.

  20. Acceleration of cardiovascular MRI using parallel imaging: basic principles, practical considerations, clinical applications and future directions

    International Nuclear Information System (INIS)

    Niendorf, T.; Sodickson, D.

    2006-01-01

    Cardiovascular Magnetic Resonance (CVMR) imaging has proven to be of clinical value for non-invasive diagnostic imaging of cardiovascular diseases. CVMR requires rapid imaging; however, the speed of conventional MRI is fundamentally limited due to its sequential approach to image acquisition, in which data points are collected one after the other in the presence of sequentially-applied magnetic field gradients and radiofrequency coils to acquire multiple data points simultaneously, and thereby to increase imaging speed and efficiency beyond the limits of purely gradient-based approaches. The resulting improvements in imaging speed can be used in various ways, including shortening long examinations, improving spatial resolution and anatomic coverage, improving temporal resolution, enhancing image quality, overcoming physiological constraints, detecting and correcting for physiologic motion, and streamlining work flow. Examples of these strategies will be provided in this review, after some of the fundamentals of parallel imaging methods now in use for cardiovascular MRI are outlined. The emphasis will rest upon basic principles and clinical state-of-the art cardiovascular MRI applications. In addition, practical aspects such as signal-to-noise ratio considerations, tailored parallel imaging protocols and potential artifacts will be discussed, and current trends and future directions will be explored. (orig.)