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Sample records for agent-enhanced mri measuring

  1. Assessment of the coronary venous system in heart failure patients by blood pool agent enhanced whole-heart MRI

    International Nuclear Information System (INIS)

    To investigate the feasibility of MRI for non-invasive assessment of the coronary sinus (CS) and the number and course of its major tributaries in heart failure patients. Fourteen non-ischaemic heart failure patients scheduled for cardiac resynchronisation therapy (CRT) underwent additional whole-heart coronary venography. MRI was performed 1 day before device implantation. The visibility, location and dimensions of the CS and its major tributaries were assessed and the number of potential implantation sites identified. The MRI results were validated by X-ray venography conventionally acquired during the device implantation procedure. The right atrium (RA), CS and mid-cardiac vein (MCV) could be visualised in all patients. 36% of the identified candidate branches were located posterolaterally, 48% laterally and 16% anterolaterally. The average diameter of the CS was quantified as 9.8 mm, the posterior interventricular vein (PIV) 4.6 mm, posterolateral segments 3.3 mm, lateral 2.9 mm and anterolateral 2.9 mm. Concordance with X-ray in terms of number and location of candidate branches was given in most cases. Contrast-enhanced MRI venography appears feasible for non-invasive pre-interventional assessment of the course of the CS and its major tributaries. (orig.)

  2. Biliary cystadenoma with bile duct communication depicted on liver-specific contrast agent-enhanced MRI in a child

    International Nuclear Information System (INIS)

    Biliary cystadenoma is a benign, but potentially malignant, cystic neoplasm of the biliary ducts occurring most commonly in middle-aged females and very rarely in children. We present a 9-year-old boy with biliary cystadenoma, diagnosed by MRI using a new liver-specific contrast agent (gadoxetic acid) that is eliminated by the biliary system. The images clearly demonstrate the communication between the multiloculated cystic mass and the biliary tree, suggesting the possibility of biliary cystadenoma. Due to the malignant potential of a cystadenoma, the lesion was resected. The resection was complete and the postoperative course was uneventful. (orig.)

  3. Patients' oral hydration levels and incidence of immediate to short-term mild side-effects in contrast agent enhanced MRI diagnostics

    International Nuclear Information System (INIS)

    Aim: Gadolinium-based contrast agents for radiodiagnostic purposes can lead to side effects, including nephrotoxicity in patients with renal insufficiency. This study evaluated whether the occurrence of mild side effects from gadolinium-based contrast enhanced magnetic resonance imaging (MRI) correlates to patients' oral hydration levels. Methods: Oral fluid intake levels 24 h pre- and 24 h post-MRI, as well as incidence of mild side-effects experienced 30 min and 24 h post-MRI were recorded by using a patient self-reporting questionnaire. Results: A total of 174 patients, 29 controls, 98 administered Prohance and 47 receiving Dotarem, were enrolled. Overall, the most frequently reported side-effect was headache; nausea only occurred in patients receiving contrast agent. One or more side-effects experienced 24 h following the MRI scan were reported by 10% (controls), 24% (Prohance) and 22% (Dotarem) of patients, respectively. Multivariate ordinal regression analysis showed that only male gender (OR 0.24, 95% CI 0.11–0.53) was statistically significantly associated with a decreased incidence of side-effects 30 min after MRI. At 24-h post MRI, a lack of contrast agent (OR 0.40, 95% CI 0.09–1.74) and male gender (OR 0.46, 95% CI 0.19–1.09) were associated with fewer side-effects. Conclusions: The level oral fluid intake before and after undergoing gadolinium-based contrast-enhanced MRI does not appear to markedly affect the incidence of common undesirable mild symptoms experienced shortly after the procedure. Confounding differences between patients in reporting side-effects may contribute to these findings. - Highlights: • We assess the incidence of patient-reported side-effects after contrast-enhanced MRI. • We examine the potential impact of oral hydration levels on side-effects. • Patient reported side-effects are high compared to those reported by clinicians. • Female gender and contrast agent itself are associated with increased side

  4. Measuring MRI noise

    OpenAIRE

    Hoiting, Gerke Jan

    2005-01-01

    De MRI-scanner wordt tegenwoordig veel gebruikt voor medisch onderzoek. Het lawaai dat het apparaat produceert (110 dB en meer), is echter een storende factor die lastig te beteugelen is. Weliswaar kan het geluiddruk vooraf berekend worden, maar de tot nu gehanteerde methode geeft een foute voorspelling wanneer het over een lage geluidsdruk gaat. Gerke Hoiting stelt in zijn proefschrift een nieuwe methode voor, die bij lage geluidsdruk wel een correcte voorspelling doet. Het proefschrift beva...

  5. Measurement of MRI scanner noise

    International Nuclear Information System (INIS)

    The present paper describes a simple method for the analysis of MRI scanner noise. Besides the heating of body tissue by strong RF radiation and the formation of circular currents in the body induced bey switching field gradients, a noise level of more than 100 dB(A) during the measurement belongs to the potential risks of MRI [1,2]. This risk is of particular concern for staff and accompanying persons who remain close to the scanner for different reasons (e.g., monitoring of anesthetized patients, reassuring of children). For this reason, and given the scanty information on noise provided in the manuals of the scanners, it is useful to quantify the noise level more exactly. This applies also to the evaluation of different sound-reducing methods for the patient. This presents the results of noise level measurements in the tomograph and in its surrounding, with and without noise reduction by headphones. (orig.)

  6. Whole-body MRI (WB-MRI) versus axial skeleton MRI (AS-MRI) to detect and measure bone metastases in prostate cancer (PCa)

    International Nuclear Information System (INIS)

    To compare whole-body MRI (WB-MRI) and axial skeleton MRI (AS-MRI) in detecting and measuring bone metastases in patients with prostate cancer (PCa). WB-MRI and AS-MRI examinations were performed in 60 patients with PCa at high risk of metastases. Two radiologists separately categorised the AS-MRI and WB-MRI as negative or positive for metastases, and measured focal metastases using the ''Response evaluation criteria in solid tumours'' (RECIST) criteria transposed to bone. One radiologist reviewed all examinations 2 months later. Inter- and intraobserver agreements in establishing the presence/absence of metastases were calculated. Bland-Altman plots were used to assess measurement agreement between AS-MRI and WB-MRI. Strong to perfect inter- and intraobserver agreements were found between AS-MRI and WB-MRI in defining the presence/absence of bone metastases. There were no patients with isolated ''peripheral'' metastases at WB-MRI, missed at AS-MRI. There was no difference in lesion count between the two radiologists. AS-MRI and WB-MRI provided statistically equivalent RECIST values for one radiologist and slightly lower values at AS-MRI for the other. In our series of PCa patients, AS-MRI and WB-MRI were equivalent in determining the presence/absence of bone metastases and provided similar evaluation of the metastatic burden. (orig.)

  7. Whole-body MRI (WB-MRI) versus axial skeleton MRI (AS-MRI) to detect and measure bone metastases in prostate cancer (PCa)

    Energy Technology Data Exchange (ETDEWEB)

    Lecouvet, F.E.; Simon, M.; Berg, B.C.V.; Simoni, P. [Universite Catholique de Louvain, Cliniques Universitaires St Luc, Department of Radiology and Medical Imaging, Brussels (Belgium); Tombal, B. [Universite Catholique de Louvain, Cliniques Universitaires St Luc, Department of Urology, Brussels (Belgium); Jamart, J. [Universite Catholique de Louvain, Clinique Universitaire de Mont-Godinne, Center of Biostatistics and Medical Documentation, Yvoir (Belgium)

    2010-12-15

    To compare whole-body MRI (WB-MRI) and axial skeleton MRI (AS-MRI) in detecting and measuring bone metastases in patients with prostate cancer (PCa). WB-MRI and AS-MRI examinations were performed in 60 patients with PCa at high risk of metastases. Two radiologists separately categorised the AS-MRI and WB-MRI as negative or positive for metastases, and measured focal metastases using the ''Response evaluation criteria in solid tumours'' (RECIST) criteria transposed to bone. One radiologist reviewed all examinations 2 months later. Inter- and intraobserver agreements in establishing the presence/absence of metastases were calculated. Bland-Altman plots were used to assess measurement agreement between AS-MRI and WB-MRI. Strong to perfect inter- and intraobserver agreements were found between AS-MRI and WB-MRI in defining the presence/absence of bone metastases. There were no patients with isolated ''peripheral'' metastases at WB-MRI, missed at AS-MRI. There was no difference in lesion count between the two radiologists. AS-MRI and WB-MRI provided statistically equivalent RECIST values for one radiologist and slightly lower values at AS-MRI for the other. In our series of PCa patients, AS-MRI and WB-MRI were equivalent in determining the presence/absence of bone metastases and provided similar evaluation of the metastatic burden. (orig.)

  8. An RF dosimeter for independent SAR measurement in MRI scanners

    International Nuclear Information System (INIS)

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B1) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average

  9. Normal Corpus Callosum Dimensions Measured by MRI

    International Nuclear Information System (INIS)

    As a result of measuring the size of corpus callosum in normal Korean people by using MRI, the following conclusions were obtained. 1. Maximum, minimum, and mean values by the region in whole subjects 1) Anteroposterior length amounted to the mean with 69.30 mm, the minimum with 50.70 mm, and the maximum with 80.40 mm. 2) Diameter of genu amounted to the mean with 11.93 mm, the minimum with 6.00 mm, and the maximum with 18.50 mm. 3) Diameter of mid body amounted to the mean with 7.00 mm, the minimum with 3.40 mm, and the maximum with 10.40 mm. 4) Diameter of narrowing portion amounted to the mean with 4.51 mm, the minimum with 0.80 mm, and the maximum with 9.50 mm. 5) Diameter of splenium amounted to the mean with 12.17 mm, the minimum with 6.90 mm, and the maximum with 17.20 mm. 2. Comparison by region according to the gender in the whole subjects 1) Anteroposterior length was bigger in men than in women, and showed the significant difference depending on gender. 2) Diameter of genu, diameter of mid body, and diameter of narrowing portion were bigger in men than in women, but there was no significant difference. 3) Diameter of splenium was bigger in men than in women, and showed the statistically significant difference. 3. Comparison by region according to the age in the whole subjects 1) Anteroposterior length was the biggest in the 50s at the age, and was smaller in heir 10s than other age levels. In addition, the significant difference was indicated depending on age. 2) Diameter of genu and diameter of mid body were the biggest in their 30s, and were smaller in the 60s than other age levels. And, the statistically significant difference was indicated. 3) Diameter of narrowing portion was the thickest in their 20s, and was thinner in their 60s than other age levels. And, the significant difference was indicated depending on age. 4) Diameter of splenium was the thickest in their 30s, and was thinner in their 10s than other age levels. And, the statistically

  10. Normal Corpus Callosum Dimensions Measured by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ham Gyum [Dept. of Radiological Technology, Ansan College, Ansan (Korea, Republic of)

    2008-09-15

    As a result of measuring the size of corpus callosum in normal Korean people by using MRI, the following conclusions were obtained. 1. Maximum, minimum, and mean values by the region in whole subjects 1) Anteroposterior length amounted to the mean with 69.30 mm, the minimum with 50.70 mm, and the maximum with 80.40 mm. 2) Diameter of genu amounted to the mean with 11.93 mm, the minimum with 6.00 mm, and the maximum with 18.50 mm. 3) Diameter of mid body amounted to the mean with 7.00 mm, the minimum with 3.40 mm, and the maximum with 10.40 mm. 4) Diameter of narrowing portion amounted to the mean with 4.51 mm, the minimum with 0.80 mm, and the maximum with 9.50 mm. 5) Diameter of splenium amounted to the mean with 12.17 mm, the minimum with 6.90 mm, and the maximum with 17.20 mm. 2. Comparison by region according to the gender in the whole subjects 1) Anteroposterior length was bigger in men than in women, and showed the significant difference depending on gender. 2) Diameter of genu, diameter of mid body, and diameter of narrowing portion were bigger in men than in women, but there was no significant difference. 3) Diameter of splenium was bigger in men than in women, and showed the statistically significant difference. 3. Comparison by region according to the age in the whole subjects 1) Anteroposterior length was the biggest in the 50s at the age, and was smaller in heir 10s than other age levels. In addition, the significant difference was indicated depending on age. 2) Diameter of genu and diameter of mid body were the biggest in their 30s, and were smaller in the 60s than other age levels. And, the statistically significant difference was indicated. 3) Diameter of narrowing portion was the thickest in their 20s, and was thinner in their 60s than other age levels. And, the significant difference was indicated depending on age. 4) Diameter of splenium was the thickest in their 30s, and was thinner in their 10s than other age levels. And, the statistically

  11. Triphasic MRI of pelvic organ descent: sources of measurement error

    Energy Technology Data Exchange (ETDEWEB)

    Morren, Geert L. [Bowel and Digestion Centre, The Oxford Clinic, 38 Oxford Terrace, Christchurch (New Zealand)]. E-mail: geert_morren@hotmail.com; Balasingam, Adrian G. [Christchurch Radiology Group, P.O. Box 21107, 4th Floor, Leicester House, 291 Madras Street, Christchurch (New Zealand); Wells, J. Elisabeth [Department of Public Health and General Medicine, Christchurch School of Medicine, St. Elmo Courts, Christchurch (New Zealand); Hunter, Anne M. [Christchurch Radiology Group, P.O. Box 21107, 4th Floor, Leicester House, 291 Madras Street, Christchurch (New Zealand); Coates, Richard H. [Christchurch Radiology Group, P.O. Box 21107, 4th Floor, Leicester House, 291 Madras Street, Christchurch (New Zealand); Perry, Richard E. [Bowel and Digestion Centre, The Oxford Clinic, 38 Oxford Terrace, Christchurch (New Zealand)

    2005-05-01

    Purpose: To identify sources of error when measuring pelvic organ displacement during straining using triphasic dynamic magnetic resonance imaging (MRI). Materials and methods: Ten healthy nulliparous woman underwent triphasic dynamic 1.5 T pelvic MRI twice with 1 week between studies. The bladder was filled with 200 ml of a saline solution, the vagina and rectum were opacified with ultrasound gel. T2 weighted images in the sagittal plane were analysed twice by each of the two observers in a blinded fashion. Horizontal and vertical displacement of the bladder neck, bladder base, introitus vaginae, posterior fornix, cul-de sac, pouch of Douglas, anterior rectal wall, anorectal junction and change of the vaginal axis were measured eight times in each volunteer (two images, each read twice by two observers). Variance components were calculated for subject, observer, week, interactions of these three factors, and pure error. An overall standard error of measurement was calculated for a single observation by one observer on a film from one woman at one visit. Results: For the majority of anatomical reference points, the range of displacements measured was wide and the overall measurement error was large. Intra-observer error and week-to-week variation within a subject were important sources of measurement error. Conclusion: Important sources of measurement error when using triphasic dynamic MRI to measure pelvic organ displacement during straining were identified. Recommendations to minimize those errors are made.

  12. Novel Measurement Technique of the Tibial Slope on Conventional MRI

    OpenAIRE

    Hudek, Robert; Schmutz, Silvia; Regenfelder, Felix; Fuchs, Bruno; Koch, Peter P.

    2009-01-01

    The posterior inclination of the tibial plateau, which is referred to as posterior tibial slope, is determined routinely on lateral radiographs. However, radiographically, it is not always possible to reliably recognize the lateral plateau, making a separate assessment of the medial and lateral plateaus difficult. We propose a technique to measure the plateaus separately by defining a tibial longitudinal axis on a conventional MRI. The medial plateau posterior tibial slope obtained from radio...

  13. Postmortem validation of MRI cortical volume measurements in MS.

    Science.gov (United States)

    Popescu, Veronica; Klaver, Roel; Versteeg, Adriaan; Voorn, Pieter; Twisk, Jos W R; Barkhof, Frederik; Geurts, Jeroen J G; Vrenken, Hugo

    2016-06-01

    Grey matter (GM) atrophy is a prominent aspect of multiple sclerosis pathology and an important outcome in studies. GM atrophy measurement requires accurate GM segmentation. Several methods are used in vivo for measuring GM volumes in MS, but assessing their validity in vivo remains challenging. In this postmortem study, we evaluated the correlation between postmortem MRI cortical volume or thickness and the cortical thickness measured on histological sections. Sixteen MS brains were scanned in situ using 3DT1-weighted MRI and these images were used to measure regional cortical volume using FSL-SIENAX, FreeSurfer, and SPM, and regional cortical thickness using FreeSurfer. Subsequently, cortical thickness was measured histologically in 5 systematically sampled cortical areas. Linear regression analyses were used to evaluate the relation between MRI regional cortical volume or thickness and histological cortical thickness to determine which postprocessing technique was most valid. After correction for multiple comparisons, we observed a significant correlation with the histological cortical thickness for FSL-SIENAX cortical volume with manual editing (std. β = 0.345, adjusted R(2)  = 0.105, P = 0.005), and FreeSurfer cortical volume with manual editing (std. β = 0.379, adjusted R(2)  = 0.129, P = 0.003). In addition, there was a significant correlation between FreeSurfer cortical thickness with manual editing and histological cortical thickness (std. β = 0.381, adjusted R(2)  = 0.130, P = 0.003). The results support the use of FSL-SIENAX and FreeSurfer in cases of severe MS pathology. Interestingly none of the methods were significant in automated mode, which supports the use of manual editing to improve the automated segmentation. Hum Brain Mapp 37:2223-2233, 2016. © 2016 Wiley Periodicals, Inc. PMID:26945922

  14. Technological advances in MRI measurement of brain perfusion.

    Science.gov (United States)

    Duyn, Jeff H; van Gelderen, Peter; Talagala, Lalith; Koretsky, Alan; de Zwart, Jacco A

    2005-12-01

    Measurement of brain perfusion using arterial spin labeling (ASL) or dynamic susceptibility contrast (DSC) based MRI has many potential important clinical applications. However, the clinical application of perfusion MRI has been limited by a number of factors, including a relatively poor spatial resolution, limited volume coverage, and low signal-to-noise ratio (SNR). It is difficult to improve any of these aspects because both ASL and DSC methods require rapid image acquisition. In this report, recent methodological developments are discussed that alleviate some of these limitations and make perfusion MRI more suitable for clinical application. In particular, the availability of high magnetic field strength systems, increased gradient performance, the use of RF coil arrays and parallel imaging, and increasing pulse sequence efficiency allow for increased image acquisition speed and improved SNR. The use of parallel imaging facilitates the trade-off of SNR for increases in spatial resolution. As a demonstration, we obtained DSC and ASL perfusion images at 3.0 T and 7.0 T with multichannel RF coils and parallel imaging, which allowed us to obtain high-quality images with in-plane voxel sizes of 1.5 x 1.5 mm(2). PMID:16267852

  15. Carpal angles as measured on CT and MRI: can we simply translate radiographic measurements?

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Stephanie; Ghumman, Simranjit S.; Moser, Thomas P. [Hopital Notre-Dame (CHUM), Department of Radiology, Centre Hospitalier de l' Universite de Montreal, Montreal, QC (Canada); Ladouceur, Martin [Research Center CHUM, Montreal, QC (Canada)

    2014-12-15

    To determine the reliability of carpal angles measured on CT and MRI compared to radiography and assess if these measurements are interchangeable. Our institutional ethic research committee approved this study. For this retrospective study, two independent observers measured the scapholunate (SL), capitolunate (CL), radiolunate (RL), and radioscaphoid (RS) angles on 21 sets of exams, with each set including a radiograph, CT, and MRI of the same wrist. Inter- and intra-observer agreements were evaluated with the intraclass correlation coefficient (ICC). Linear mixed models and two-way contingency tables were used to determine if the angles measured on cross-sectional modalities were significantly different from those obtained on radiography. Inter-observer agreement was strong (ICC >0.8) for all angles, except for the RL angle measured on MRI (ICC 0.68). Intra-observer agreement was also strong for all angles, except for the CL angle measured on CT (ICC 0.66). SL angles measured on CT and MRI were not statistically different from those measured on radiographs (p = 0.37 and 0.36, respectively), unlike CL, RL, and RS angles (p < 0.05). Accuracy between modalities varied between 76 and 86 % for the SL angle and ranged between 43 and 76 % for the other angles. CL, RL, and RS angles showed large intermodality variability. Therefore, their measurements on CT or MRI could potentially lead to miscategorization. Conversely, our data showing no significant difference between modalities, SL angle could be measured on CT and MRI to assess wrist instability with a lower risk of error. (orig.)

  16. Carpal angles as measured on CT and MRI: can we simply translate radiographic measurements?

    International Nuclear Information System (INIS)

    To determine the reliability of carpal angles measured on CT and MRI compared to radiography and assess if these measurements are interchangeable. Our institutional ethic research committee approved this study. For this retrospective study, two independent observers measured the scapholunate (SL), capitolunate (CL), radiolunate (RL), and radioscaphoid (RS) angles on 21 sets of exams, with each set including a radiograph, CT, and MRI of the same wrist. Inter- and intra-observer agreements were evaluated with the intraclass correlation coefficient (ICC). Linear mixed models and two-way contingency tables were used to determine if the angles measured on cross-sectional modalities were significantly different from those obtained on radiography. Inter-observer agreement was strong (ICC >0.8) for all angles, except for the RL angle measured on MRI (ICC 0.68). Intra-observer agreement was also strong for all angles, except for the CL angle measured on CT (ICC 0.66). SL angles measured on CT and MRI were not statistically different from those measured on radiographs (p = 0.37 and 0.36, respectively), unlike CL, RL, and RS angles (p < 0.05). Accuracy between modalities varied between 76 and 86 % for the SL angle and ranged between 43 and 76 % for the other angles. CL, RL, and RS angles showed large intermodality variability. Therefore, their measurements on CT or MRI could potentially lead to miscategorization. Conversely, our data showing no significant difference between modalities, SL angle could be measured on CT and MRI to assess wrist instability with a lower risk of error. (orig.)

  17. Measurement of femoral torsion and tibial torsion using magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    A new MRI method for the measurement of femoral torsion and tibial torsion is presented. Axial images were generated using a standard gradient echo sequence (FLASH 2D). Otherwise measurement of femoral and tibial torsion was performed according to an established CT method. The torsion angles measured using MRI were in accordance with the angles measured using the CT method. The MRI method was not more time-consuming than the CT method. In respect of radiation exposure, MRI determination of femoral and tibial torsion should be considered particularly in children and patients who have to undergo repeated torsion measurements. (orig.)

  18. An Automatic Technique for MRI Based Murine Abdominal Fat Measurement

    Directory of Open Access Journals (Sweden)

    R. A. Moats

    2011-12-01

    Full Text Available Because of the well-known relationship between obesity and high incidence of diseases, fat related research using mice models is being widely investigated in preclinical experiments. In the present study, we developed a technique to automatically measure mice abdominal adipose volume and determine the depot locations using Magnetic Resonance Imaging (MRI. Our technique includes an innovative method to detect fat tissues from MR images which not only utilizes the T1 weighted intensity information, but also takes advantage of the transverse relaxation time(T2 calculated from the multiple echo data. The technique contains both a fat optimized MRI imaging acquisition protocol that works well at 7T and a newly designed post processing methodology that can automatically accomplish the fat extraction and depot recognition without user intervention in the segmentation procedure. The post processing methodology has been integrated into easy-to-use software that we have made available via free download. The method was validated by comparing automated results with two independent manual analyses in 26 mice exhibiting different fat ratios from the obesity research project. The comparison confirms a close agreement between the results in total adipose tissue size and voxel-by-voxel overlaps.

  19. Outcome Classification of Preschool Children with Autism Spectrum Disorders Using Mri Brain Measures.

    Science.gov (United States)

    Akshoomoff, Natacha; Lord, Catherine; Lincoln, Alan J.; Courchesne, Rachel Y.; Carper, Ruth A.; Townsend, Jeanne; Courchesne, Eric

    2004-01-01

    Objective: To test the hypothesis that a combination of magnetic resonance imaging (MRI) brain measures obtained during early childhood distinguish children with autism spectrum disorders (ASD) from typically developing children and is associated with functional outcome. Method: Quantitative MRI technology was used to measure gray and white matter…

  20. Interfacial tension measurements using MRI drop shape analysis.

    Science.gov (United States)

    Hussain, R; Vogt, S J; Honari, A; Hollingsworth, K G; Sederman, A J; Mitchell, J; Johns, M L

    2014-02-18

    Accurate interfacial tension data for fluid systems such as hydrocarbons and water is essential to many applications such as reservoir oil and gas recovery predictions. Conventional interfacial tension measurement techniques typically use optical images to analyze droplet shapes but require that the continuous-phase fluid be optically transparent and that the fluids are not refractive index matched. Magnetic resonance images obtain contrast between fluids using other mechanisms such as magnetic relaxation weighting, so systems that are impossible to measure with optical methods may be analyzed. In this article, we present high-field (9.4 T) MRI images of various droplets analyzed with axisymmetric drop shape analysis. The resultant interfacial tension data show good agreement with literature data. The method is subsequently demonstrated using both opaque continuous phases and refractive-index-matched fluids. We conclude with a brief consideration of the potential to extrapolate the methodology to lower magnetic fields (0.3 T), featuring more accessible hardware; although droplet imaging is possible, resolution and stability do not currently permit accurate interfacial tension measurements. PMID:24471906

  1. The measurement of language lateralization with functional Transcranial Doppler and functional MRI. A critical evaluation.

    Directory of Open Access Journals (Sweden)

    Metten Somers

    2011-03-01

    Full Text Available Cerebral language lateralization can be assessed in several ways. In healthy subjects, functional MRI (fMRI during performance of a language task has evolved to be the most frequently applied method. Functional Transcranial Doppler (fTCD may provide a valid alternative, but has been used rarely. Both techniques have their own strengths and weaknesses and as a result may be applied in different fields of research. Until now, only one relatively small study (n=13 investigated the correlation between lateralization indices measured by fTCD and fMRI and showed a remarkably high correlation. To further evaluate the correlation between lateralization indices measured with fTCD and fMRI, we compared lateralization indices of twenty-two healthy subjects (twelve left- and ten right-handed using the same word generation paradigm for the fTCD as for the fMRI experiment. Lateralization indices measured with fTCD were highly but imperfectly correlated with lateralization indices measured with fMRI (Spearman’s rho=0.75, p<0.001. The imperfectness of the correlation can partially be explained by methodological restrictions of fMRI as well as fTCD. Our results suggest that fTCD can be a valid alternative for fMRI to measure lateralization, particularly when costs or mobility are important factors in the study design.

  2. MRI volume measurement of the brain in schizophrenia

    International Nuclear Information System (INIS)

    The T1-weighted images of whole-brain three-dimensional MRI (thickness, 3 mm; interval, 3 mm) were obtained from schizophrenic patients and 20 healthy volunteers. Detailed volumetric measurement of each part in the brain was carried out. As the result, the volume of both ventricles and third ventriculus cerebri in the schizophrenic group was significantly larger than that of the control group. No significant difference was observed in terms of the volume of the bilateral frontal lobe, bilateral body of caudate nucleus division and right temporal lobe. The volume of bilateral hippocampus and left temporal lobe of the schizophrenic group was significantly smaller than that of the control group. Negative correlation was observed between symptoms and the right temporal lobe volume (r=-0.41) in the schizophrenic group. In the schizophrenic group, morphological abnormality was admitted in the hippocampus, ventriculus cerebri and left temporal lobe. The morphological abnormality of the right temporal lobe seemed to involve the expression of negative symptoms. (S.Y.)

  3. MRI measurement of syrinx size before and after operation.

    OpenAIRE

    Grant, R.; Hadley, D M; Lang, D.; Condon, B; Johnston, R.; Bone, I; Teasdale, G M

    1987-01-01

    When patients with syringomyelia fail to improve after operation, factors such as incomplete cyst decompression or type of operation are often implicated. MRI has been used to confirm adequate syrinx decompression post-operatively and to compare the degree of collapse with the type of operation. Foramen magnum decompression was at least as effective in reducing cyst size as syringo-subarachnoid shunting. MRI may also provide a better classification of syringomyelia.

  4. MRI measurement of syrinx size before and after operation.

    Science.gov (United States)

    Grant, R; Hadley, D M; Lang, D; Condon, B; Johnston, R; Bone, I; Teasdale, G M

    1987-12-01

    When patients with syringomyelia fail to improve after operation, factors such as incomplete cyst decompression or type of operation are often implicated. MRI has been used to confirm adequate syrinx decompression post-operatively and to compare the degree of collapse with the type of operation. Foramen magnum decompression was at least as effective in reducing cyst size as syringo-subarachnoid shunting. MRI may also provide a better classification of syringomyelia. PMID:3437304

  5. Validation of SPAMM tagged MRI based measurement of 3D soft tissue deformation

    NARCIS (Netherlands)

    K.M. Moerman; A.M.J. Sprengers; C.K. Simms; R.M. Lamerichs; J. Stoker; A.J. Nederveen

    2011-01-01

    This study presents and validates a novel (non-ECG-triggered) MRI sequence based on spatial modulation of the magnetization (SPAMM) to noninvasively measure 3D (quasistatic) soft tissue deformations using only six acquisitions (three static and three indentations). In the current SPAMM tagged MRI ap

  6. Development of Human Muscle Protein Measurement with MRI

    Science.gov (United States)

    Lin, Chen; Evans, Harlan; Leblanc, Adrian D.

    1997-01-01

    It is known that micro-gravity has a strong influence on the human musculoskeletal system. A number of studies have shown that significant changes in skeletal muscles occur in both space flight and bedrest simulation. In our 5 week bedrest study, the cross-sectional area of soleus-gastrocnemius decreased about 12% while the cross-sectional area of anterior calf muscles decreased about 4%. Using volume measurements, these losses increased after 17 weeks to approximately 30% and 21% respectively. Significant muscle atrophy was also found on the SL-J crew members after only 8 days in space. It is important that these effects are fully understood so that countermeasures can be developed. The same knowledge might also be useful in preventing muscle atrophy related to other medical problems. A major problem with anatomical measurements of muscle during bed rest and microgravity is the influence of fluid shifts and water balance on the measurement of muscle volume, especially when the exposure duration is short and the atrophy is relatively small. Fluid shifts were documented in Skylab by visual observations of blood vessel distention, rapid changes in limb volume, center of mass measurements and subjective descriptions such as puffy faces and head fullness. It has been reported that the muscle water content of biopsied soleus muscles decreased following 8 hours of head down tilt bed rest. Three aspects of fluid shifts that can affect volume measurements are: first, the shift of fluid that occurs whenever there is a change from upright to a recumbent position and vice versa; second, the potential for fluid accumulation in the lower limbs resulting from muscle damage caused by overextending atrophied muscle or swelling caused by deconditioned precapillary sphincter muscles during reambulation; third, the net change of hydration level during and after bed rest or spaceflight. Because of these transitory fluid shifts, muscle protein is expected to represent muscle capacity

  7. Physiological measurements using ultra-high field fMRI: a review

    International Nuclear Information System (INIS)

    Functional MRI (fMRI) has grown to be the neuroimaging technique of choice for investigating brain function. This topical review provides an outline of fMRI methods and applications, with a particular emphasis on the recent advances provided by ultra-high field (UHF) scanners to allow functional mapping with greater sensitivity and improved spatial specificity. A short outline of the origin of the blood oxygenation level dependent (BOLD) contrast is provided, followed by a review of BOLD fMRI methods based on gradient-echo (GE) and spin-echo (SE) contrast. Phase based fMRI measures, as well as perfusion contrast obtained with the technique of arterial spin labelling (ASL), are also discussed. An overview of 7 T based functional neuroimaging is provided, outlining the potential advances to be made and technical challenges to be addressed. (topical review)

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

    International Nuclear Information System (INIS)

    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)

  9. Validation of SPAMM Tagged MRI Based Measurement of 3D Soft Tissue Deformation

    OpenAIRE

    Kevin M. Moerman; Sprengers, Andre M. J.; Ciaran K. Simms; Lamerichs, Rolf M.; Stoker, Jaap; Aart J. Nederveen

    2016-01-01

    This study presents and validates a novel (non-ECG-triggered) MRI sequence based on SPAtial Modulation of the Magnetization (SPAMM) to non-invasively measure 3D (quasi-static) soft tissue deformations using only six acquisitions (three static and three indentations). In current SPAMM tagged MRI approaches data is typically constructed from many repeated motion cycles. This has so far restricted its application to the measurement of highly repeatable and periodic movements (e.g. cardiac deform...

  10. Ultrasound and MRI measurements of joint cartilage in healthy children. A validation study

    DEFF Research Database (Denmark)

    Spannow, A H; Stenboeg, E; Jensen, Mogens Pfeiffer;

    2011-01-01

    measurements of cartilage thickness in target joints in healthy children by comparing them with MRI. Materials and Methods: Twenty-five healthy Caucasian children (17 boys/ 8 girls), mean age 11.33 years, were examined with MRI (1.5 T, fat-suppressed T 1-weighted 3D sequences) and US (real-time Hitachi EUB...... 6500 CFM, B-mode 6 - 14 MHz linear transducer) in the right knee, ankle, wrist, metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. US was obtained according to the EULAR standard scans. Results: All differences in cartilage thickness measurements between MRI and US were less than 0.......5 millimeters. The coefficient of variation (CV) was found to be good (16 %) except for in the case of the wrist joint (20 %). Conclusion: We found a good level of agreement and no significant systematic joint size-related differences in cartilage thickness measurements between MRI and US. US appears to be a...

  11. Measurement of the AT and the CCD angle of macerated cadaver femora: a comparative study between CT and MRI measurements

    International Nuclear Information System (INIS)

    Purpose: To compare measurements of the real AT (femoral antetorsion) and CCD (caput-scollum-diaphysis) angle by computed tomography (CT) and magnetic resonance imaging (MRI) of hip specimen using direct measurements as reference standard, and to show that measurements by MRI can replace CT measurements and ma help avoiding X-ray exposition. Materials and methods: CT and MRI measurements were obtained on 25 in water-arrested macerated human femora. Postprocessing was done by 4 independent readers on a workstation using a dedicated 3D-software. Direct measurements of the real AT and the CCD angle were used as reference standard. The analysis included Student's test for paired values, interobserver variability using intra-class correlation coefficients (ICC), maximum and middle divergence of the angles, and Bland-Altman plots. Results: For determining AT and the CCD angle with CT and MRI, good correlation was found between the 4 readers and with measurements using the reference standard. ICCs were 0.97 and 0.90 for measuring AT and CCD angle with CT, and 0.95 and 0.71 for measurements with MRI, respectively. Mean divergence between CT measurements and those of the reference standard was 0.8 for AT and 0.7 for the CDD-angle. Mean divergence between MRI measurements and those of the reference standard was 0.3 for AT and -0.4 for the CCD-angle. Mean divergences between CT and MRI measurements of AT and CCD-angle were 0.5 . Neither systematic errors nor dependences on the qualitative size of the reference data were evident in the divergences of measurements. (orig.)

  12. Which factors influence MRI-pathology concordance of tumour size measurements in breast cancer?

    International Nuclear Information System (INIS)

    To assess MRI-pathology concordance and factors influencing tumour size measurement in breast cancer. MRI tumour size (greatest diameter in anatomical planes (MRI-In-Plane) and greatest diameter along main tumour axis (MRI-MPR)) of 115 consecutive breast lesions (59 invasive lobular carcinoma, 46 invasive ductal carcinoma, and 10 ductal carcinoma in situ) was retrospectively compared to size measured at histopathology (pT size (Path-TNM) and greatest tumour diameter as relevant for excision (Path-Diameter; reference standard)). Histopathological tumour types, preoperative palpability, surgical management, additional high-risk lesions, and BI-RADS lesion type (mass versus non-mass enhancements) were assessed as possible influencing factors. Systematic errors were most pronounced between MRI-MPR and Path-TNM (7.1 mm, limits of agreement (LoA) [-21.7; 35.9]), and were lowest between MRI-In-Plane and Path-Diameter (0.2 mm, LoA [-19.7; 20.1]). Concordance rate of MRI-In-Plane with Path-Diameter was 86 % (97/113), overestimation 9 % (10/113) and underestimation 5 % (6/113); BI-RADS mass lesions were overestimated in 7 % (6/81) versus 41 % (13/32) for non-mass enhancements. On multivariate analysis only BI-RADS lesion type significantly influenced MRI-pathology concordance (p < 0.001). 2/59 (3 %) ILC did not enhance. Concordance rate varies according to the execution of MRI and histopathological measurements. Beyond this only non-mass enhancement significantly predicted discordance. (orig.)

  13. Which factors influence MRI-pathology concordance of tumour size measurements in breast cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Rominger, M.; Frauenfelder, T. [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland); Berg, D. [Urbankrankenhaus Berlin, Anesthesiology, Berlin (Germany); Ramaswamy, A. [University Hospital Marburg, Pathology, Marburg (Germany); Timmesfeld, N. [Philipps University Marburg, Institute for Medical Biometry and Epidemiology, Marburg (Germany)

    2016-05-15

    To assess MRI-pathology concordance and factors influencing tumour size measurement in breast cancer. MRI tumour size (greatest diameter in anatomical planes (MRI-In-Plane) and greatest diameter along main tumour axis (MRI-MPR)) of 115 consecutive breast lesions (59 invasive lobular carcinoma, 46 invasive ductal carcinoma, and 10 ductal carcinoma in situ) was retrospectively compared to size measured at histopathology (pT size (Path-TNM) and greatest tumour diameter as relevant for excision (Path-Diameter; reference standard)). Histopathological tumour types, preoperative palpability, surgical management, additional high-risk lesions, and BI-RADS lesion type (mass versus non-mass enhancements) were assessed as possible influencing factors. Systematic errors were most pronounced between MRI-MPR and Path-TNM (7.1 mm, limits of agreement (LoA) [-21.7; 35.9]), and were lowest between MRI-In-Plane and Path-Diameter (0.2 mm, LoA [-19.7; 20.1]). Concordance rate of MRI-In-Plane with Path-Diameter was 86 % (97/113), overestimation 9 % (10/113) and underestimation 5 % (6/113); BI-RADS mass lesions were overestimated in 7 % (6/81) versus 41 % (13/32) for non-mass enhancements. On multivariate analysis only BI-RADS lesion type significantly influenced MRI-pathology concordance (p < 0.001). 2/59 (3 %) ILC did not enhance. Concordance rate varies according to the execution of MRI and histopathological measurements. Beyond this only non-mass enhancement significantly predicted discordance. (orig.)

  14. Perimeter Measurement of Spruce Needles Profile Using MRI

    Czech Academy of Sciences Publication Activity Database

    Mikulka, J.; Gescheidtová, E.; Bartušek, Karel

    Cambridge: Electromagnetic Academy, 2009 - (Kong, J.), s. 1128-1131 ISBN 978-1-934142-08-0. ISSN 1559-9450. [Progress in Electromagnetic s Research Symposium 2009 Beijing. Beijing (CN), 23.04.2009-27.04.2009] R&D Projects: GA ČR(CZ) GA102/07/0389 Institutional research plan: CEZ:AV0Z20650511 Keywords : MRI * Spruce Needles Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  15. Hyperemic flow heterogeneity within the calf, foot, and forearm measured with continuous arterial spin labeling MRI

    OpenAIRE

    Wu, Wen-Chau; Wang, Jiongjiong; Detre, John A.; Wehrli, Felix W.; Mohler, Emile; Ratcliffe, Sarah J.; Floyd, Thomas F

    2008-01-01

    Arterial spin labeling (ASL) is a noninvasive magnetic resonance imaging (MRI) technique for microvascular blood flow measurement. We used a continuous ASL scheme (CASL) to investigate the hyperemic flow difference between major muscle groups in human extremities. Twenty-four healthy subjects with no evidence of vascular disease were recruited. MRI was conducted on a 3.0 Tesla Siemens Trio whole body system with a transmit/receive knee coil. A nonmagnetic orthopedic tourniquet system was used...

  16. Comparison of neurite density measured by MRI and histology after TBI.

    Directory of Open Access Journals (Sweden)

    Shiyang Wang

    Full Text Available BACKGROUND: Functional recovery after brain injury in animals is improved by marrow stromal cells (MSC which stimulate neurite reorganization. However, MRI measurement of neurite density changes after injury has not been performed. In this study, we investigate the feasibility of MRI measurement of neurite density in an animal model of traumatic brain injury (TBI with and without MSC treatment. METHODS: Fifteen male Wistar rats, were treated with saline (n = 6 or MSCs (n = 9 and were sacrificed at 6 weeks after controlled cortical impact (CCI. Healthy non-CCI rats (n = 5, were also employed. Ex-vivo MRI scans were performed two days after the rats were sacrificed. Multiple-shell hybrid diffusion imaging encoding scheme and spherical harmonic expansion of a two-compartment water diffusion displacement model were used to extract neurite related parameters. Bielshowski and Luxol Fast blue was used for staining axons and myelin, respectively. Modified Morris water maze and neurological severity score (mNSS test were performed for functional evaluation. The treatment effects, the correlations between neurite densities measured by MRI and histology, and the correlations between MRI and functional variables were calculated by repeated measures analysis of variance, the regression correlation analysis tests, and spearman correlation coefficients. RESULTS: Neurite densities exhibited a significant correlation (R(2>0.80, p<1E-20 between MRI and immuno-histochemistry measurements with 95% lower bound of the intra-correlation coefficient (ICC as 0.86. The conventional fractional anisotropy (FA correlated moderately with histological neurite density (R(2 = 0.59, P<1E-5 with 95% lower bound of ICC as 0.76. MRI data revealed increased neurite reorganization with MSC treatment compared with saline treatment, confirmed by histological data from the same animals. mNSS were significantly correlated with MRI neurite density in the hippocampus region

  17. Measurement of Liver Iron Concentration by MRI Is Reproducible

    Directory of Open Access Journals (Sweden)

    José María Alústiza

    2015-01-01

    Full Text Available Purpose. The objectives were (i construction of a phantom to reproduce the behavior of iron overload in the liver by MRI and (ii assessment of the variability of a previously validated method to quantify liver iron concentration between different MRI devices using the phantom and patients. Materials and Methods. A phantom reproducing the liver/muscle ratios of two patients with intermediate and high iron overload. Nine patients with different levels of iron overload were studied in 4 multivendor devices and 8 of them were studied twice in the machine where the model was developed. The phantom was analysed in the same equipment and 14 times in the reference machine. Results. FeCl3 solutions containing 0.3, 0.5, 0.6, and 1.2 mg Fe/mL were chosen to generate the phantom. The average of the intramachine variability for patients was 10% and for the intermachines 8%. For the phantom the intramachine coefficient of variation was always below 0.1 and the average of intermachine variability was 10% for moderate and 5% for high iron overload. Conclusion. The phantom reproduces the behavior of patients with moderate or high iron overload. The proposed method of calculating liver iron concentration is reproducible in several different 1.5 T systems.

  18. Recent development in noninvasive brain activity measurement by functional magnetic resonance imaging (fMRI)

    International Nuclear Information System (INIS)

    fMRI (functional magnetic resonance imaging) is a non-invasive brain imaging technique with which the distribution of neural activity is estimated by measuring local blood flow changes. Blood-oxygenation-level-dependent (BOLD) method measures changes in the density of deoxidized hemoglobin in blood caused by blood flow changes, while other methods have been developed to measure the blood flow changes directly. Effort has been expended to realize a submillimeter spatial resolution by using higher static magnetic field. fMRI has been carried out with various mental tasks, and many important findings have been made on the localization of higher brain functions. (author)

  19. Attenuation of artifacts in EEG signals measured inside an MRI scanner using constrained independent component analysis

    International Nuclear Information System (INIS)

    Integration of electroencephalography (EEG) and functional magnetic imaging (fMRI) resonance will allow analysis of the brain activities at superior temporal and spatial resolution. However simultaneous acquisition of EEG and fMRI is hindered by the enhancement of artifacts in EEG, the most prominent of which are ballistocardiogram (BCG) and electro-oculogram (EOG) artifacts. The situation gets even worse if the evoked potentials are measured inside MRI for their minute responses in comparison to the spontaneous brain responses. In this study, we propose a new method of attenuating these artifacts from the spontaneous and evoked EEG data acquired inside an MRI scanner using constrained independent component analysis with a priori information about the artifacts as constraints. With the proposed techniques of reference function generation for the BCG and EOG artifacts as constraints, our new approach performs significantly better than the averaged artifact subtraction (AAS) method. The proposed method could be an alternative to the conventional ICA method for artifact attenuation, with some advantages. As a performance measure we have achieved much improved normalized power spectrum ratios (INPS) for continuous EEG and correlation coefficient (cc) values with outside MRI visual evoked potentials for visual evoked EEG, as compared to those obtained with the AAS method. The results show that our new approach is more effective than the conventional methods, almost fully automatic, and no extra ECG signal measurements are involved

  20. Validation of SPAMM Tagged MRI Based Measurement of 3D Soft Tissue Deformation

    CERN Document Server

    Moerman, Kevin M; Simms, Ciaran K; Lamerichs, Rolf M; Stoker, Jaap; Nederveen, Aart J

    2016-01-01

    This study presents and validates a novel (non-ECG-triggered) MRI sequence based on SPAtial Modulation of the Magnetization (SPAMM) to non-invasively measure 3D (quasi-static) soft tissue deformations using only six acquisitions (three static and three indentations). In current SPAMM tagged MRI approaches data is typically constructed from many repeated motion cycles. This has so far restricted its application to the measurement of highly repeatable and periodic movements (e.g. cardiac deformation). In biomechanical applications where soft tissue deformation is artificially induced, often by indentation, significant repeatability constraints exist and, for clinical applications, discomfort and health issues generally preclude a large number of repetitions.

  1. Development of an outdoor MRI system for measuring flow in a living tree.

    Science.gov (United States)

    Nagata, Akiyoshi; Kose, Katsumi; Terada, Yasuhiko

    2016-04-01

    An outdoor MRI system for noninvasive, long-term measurements of sap flow in a living tree in its natural environment has been developed. An open-access, 0.2 T permanent magnet with a 160 mm gap was combined with a radiofrequency probe, planar gradient coils, electromagnetic shielding, several electrical units, and a waterproofing box. Two-dimensional cross-sectional images were acquired for a ring-porous tree, and the anatomical structures, including xylem and phloem, were identified. The MRI flow measurements demonstrated the diurnal changes in flow velocity in the stem on a per-pixel basis. These results demonstrate that our outdoor MRI system is a powerful tool for studies of water transport in outdoor trees. PMID:26896868

  2. Development of an outdoor MRI system for measuring flow in a living tree

    Science.gov (United States)

    Nagata, Akiyoshi; Kose, Katsumi; Terada, Yasuhiko

    2016-04-01

    An outdoor MRI system for noninvasive, long-term measurements of sap flow in a living tree in its natural environment has been developed. An open-access, 0.2 T permanent magnet with a 160 mm gap was combined with a radiofrequency probe, planar gradient coils, electromagnetic shielding, several electrical units, and a waterproofing box. Two-dimensional cross-sectional images were acquired for a ring-porous tree, and the anatomical structures, including xylem and phloem, were identified. The MRI flow measurements demonstrated the diurnal changes in flow velocity in the stem on a per-pixel basis. These results demonstrate that our outdoor MRI system is a powerful tool for studies of water transport in outdoor trees.

  3. Reliability of MRI in measuring tongue tumour thickness: a 1.5t study

    International Nuclear Information System (INIS)

    Background: Tongue tumour thickness has been shown to have a correlation with neck nodal metastasis and hence patient survival. Current AJCC guidelines recommend inclusion of tongue tumour thickness measurement in routine radiologic staging. Several studies have attempted to define the accuracy of MRI in measuring tongue tumour thickness. The aim of our study was to compare tongue tumour thickness measured at T2-weighted and STIR sequences with histologic tongue tumour thickness. Methods: Twenty-eight consecutive patients of tongue cancer who had undergone glossectomy were selected retrospectively. Tumours were measured in both STIR axial and T2-weighted coronal images and compared with histologic tumour thickness on resected specimens. Pearson's analysis was performed to determine the degree of correlation. Paired samples t-test was also used for comparison of mean tumour thicknesses measured on MRI with mean histologic tumour thickness. Results: Pearson correlation analysis showed good correlation of tumour thickness measured on MRI with actual histologic tumour thickness (R=0.876). Conclusion: MRI provides a satisfactory prediction of tongue tumour thickness which in turn can be used to determine the need for elective neck dissection in these patients. (author)

  4. Vibration isolation for seismocardiogram measurement in the openMRI-guided operating theater

    International Nuclear Information System (INIS)

    The purpose of this study is to establish a method of measuring precisely the seismocardiogram (SCG) of a patient who lying in an open magnetic resonance imaging (openMRI) machine for myocardial ischemia monitoring during surgery. Vibration isolation was examined by analyzing the gantry vibration during MRI scanning and the SCG of a healthy volunteer. The MRI gantry vibration had maximum amplitude of 2.5 m/s2, which are several peaks more than 100 Hz up to 500 Hz. Up to 94% reduction in amplitude was observed in the patient bed vibration under both T1-weighted and T2-weighted sequences. The power spectrum center of the patient bed vibration was more than 30 Hz. The maximum amplitude of SCG was 0.92 m/s2 and a FET analysis revealed that the SCG was not higher than 25 Hz. The signal-to-noise ratio between the SCG and the patient bed vibration was calculated to be from 4 to 7. These results demonstrate that the peak acceleration of the SCG can be monitored during open MRI scanning. In conclusion, vibration analysis showed the feasibility of using the piezoelectric acceleration sensor for seismocardiogram measurement in the open MRI-guided operating theater. (author)

  5. Velocity, correlation time and diffusivity measurements in highly turbulent gas flow by an MRI method

    Science.gov (United States)

    Yang, Zhi; Newling, Ben

    2007-03-01

    We present non-invasive, quantitative MRI wind-tunnel measurements in flowing gas (velocity > 10 m/s) at high Reynolds numbers (Re > 10^5). Our measurement method is three-dimensional and has the potential for saving time over traditional pointwise techniques. The method is suitable for liquids and for gases. We demonstrate the use of the technique on different test sections (bluff obstruction, clark Y-wing and cylinder). The mean velocity of gas flowing past those sections has been measured. We also investigate methods to measure flow correlation times by changing the acquisition interval between excitation of the sample and detection of the signal. This may be accomplished by making separate measurements or by using a multiple-point acquisition method. A measurement of correlation time allows us to map turbulent diffusivity. The MRI data are compared with computational fluid dynamics.

  6. MRI Measurements of Iron Load in Transfusion-Dependent Patients: Implementation, Challenges, and Pitfalls.

    Science.gov (United States)

    Quinn, Charles T; St Pierre, Tim G

    2016-05-01

    Magnetic resonance imaging (MRI) has played a key role in studies of iron overload in transfusion-dependent patients, providing insights into the relations among liver and cardiac iron loading, iron chelator dose, and morbidity. Currently, there is rapid uptake of these methods into routine clinical practice as part of the management strategy for iron overload in regularly transfused patients. Given the manifold methods of data acquisition and analysis, there are several potential pitfalls that may result in inappropriate decision making. Herein, we review the challenges of establishing suitable MRI techniques for tissue iron measurement in regularly transfused patients. PMID:26713769

  7. Cardiovascular MRI in Detection and Measurement of Aortic Atheroma in Stroke/TIA patients

    OpenAIRE

    Faber, Theodore; Rippy, Ashley; Hyslop, W Brian; Hinderliter, Alan; Sen, Souvik

    2013-01-01

    Background Aortic Atheroma (AoA) is an independent risk factor for new and recurrent stroke. AoA ulceration and mobility are associated with an increased risk for brain embolism. Transesophageal echocardiography (TEE) is the gold standard for detection and measurement of AoA in stroke/TIA patients. Cardiovascular MRI (cMRI) could be an alternative, non-invasive imaging modality for stroke/TIA patients. The objective of this study was to assess the accuracy and correlation of AoA detected and ...

  8. Visual evoked potential (VEP) measured by simultaneous 64-channel EEG and 3T fMRI.

    Science.gov (United States)

    Bonmassar, G; Anami, K; Ives, J; Belliveau, J W

    1999-06-23

    We present the first simultaneous measurements of evoked potentials (EPs) and fMRI hemodynamic responses to visual stimulation. Visual evoked potentials (VEPs) were recorded both inside and outside the static 3T magnetic field, and during fMRI examination. We designed, constructed, and tested a non-magnetic 64-channel EEG recording cap. By using a large number of EEG channels it is possible to design a spatial filter capable of removing the artifact noise present when recording EEG/EPs within a strong magnetic field. We show that the designed spatial filter is capable of recovering the ballistocardiogram-contaminated original EEG signal. Isopotential plots of the electrode array recordings at the peak of the VEP response (approximately 100ms) correspond well with simultaneous fMRI observed activated areas of primary and secondary visual cortices. PMID:10501528

  9. Measurement of necrotic portion in legs-calve-perthes disease: comparison of MRI volume measurement method and catterall classification

    International Nuclear Information System (INIS)

    The purpose of this study was to evaluate the extent of necrosis of the femoral head in Legs-Calve-Perthes (LCP) disease. This involved the use of MRI, followed by volume measurement and the use of the Catterall classification system; the difference between the grade obtained using each of these approaches was then determined. (author). 21 refs., 4 figs

  10. Renal masses measuring under 2 cm: Pathologic outcomes and associations with MRI features

    Energy Technology Data Exchange (ETDEWEB)

    Rosenkrantz, Andrew B., E-mail: Andrew.Rosenkrantz@nyumc.org [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Wehrli, Natasha E. [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States); Melamed, Jonathan [Department of Pathology, 550 First Avenue, New York, NY 10016 (United States); Taneja, Samir S. [Department of Urology, Division of Urologic Oncology, 550 First Avenue, New York, NY 10016 (United States); Shaikh, Mohammed B. [Department of Radiology, NYU Langone Medical Center, 550 First Avenue, New York, NY 10016 (United States)

    2014-08-15

    Purpose: To evaluate pathologic outcomes and associations with MRI features in small renal masses measuring up to 20 mm Methods: 86 patients (61 ± 13 years; 45 M/41F) with 92 renal masses measuring up to 20 mm that underwent MRI prior to tissue diagnosis were included. Two radiologists independently evaluated all masses for microscopic lipid, hemorrhage, T2-hyperintensity, T2-homogeneity, cystic/necrotic areas, hypervascularity, enhancement homogeneity, circumscribed margins, and predominantly exophytic location. These MRI features, as well as patient age, gender, and history of RCC, were compared with pathologic findings using Fisher's exact test, unpaired t-test, and multivariate logistic regression. Results: 26.1% (24/92) of masses under 2 cm were benign, only 32.6% (30/92) were clear-cell RCC, and only 7.6% (7/92) were high-grade. Among 16 masses measuring up to 1 cm, only 12.5% (2/16) were clear-cell RCC, and none was high-grade. Within the entire cohort, no MRI or clinical feature showed a significant difference between benign and malignant lesions (p ≥ 0.053). However, for both readers, clear-cell RCC exhibited a significantly higher frequency of T2-hyperintensity, cystic/necrotic areas, and hypervascularity, and a significantly lower frequency of hemorrhage, T2-homogeneity, and enhancement homogeneity (p < 0.001–0.036). Hypervascularity was a significant independent predictor of clear-cell RCC for both readers (p = 0.002–0.007), as was T2-hyperintensity for reader 2 (p = 0.007). Conclusion: A substantial fraction of small renal masses were benign, and when malignant, largely exhibited indolent pathologic characteristics, particularly when measuring under 1 cm Although small benign and malignant masses could not be differentiated on MRI, hypervascularity showed a significant independent association with clear-cell RCC in comparison with other lesions.

  11. Distortion products in auditory fMRI research: Measurements and solutions.

    Science.gov (United States)

    Norman-Haignere, Sam; McDermott, Josh H

    2016-04-01

    Nonlinearities in the cochlea can introduce audio frequencies that are not present in the sound signal entering the ear. Known as distortion products (DPs), these added frequencies complicate the interpretation of auditory experiments. Sound production systems also introduce distortion via nonlinearities, a particular concern for fMRI research because the Sensimetrics earphones widely used for sound presentation are less linear than most high-end audio devices (due to design constraints). Here we describe the acoustic and neural effects of cochlear and earphone distortion in the context of fMRI studies of pitch perception, and discuss how their effects can be minimized with appropriate stimuli and masking noise. The amplitude of cochlear and Sensimetrics earphone DPs were measured for a large collection of harmonic stimuli to assess effects of level, frequency, and waveform amplitude. Cochlear DP amplitudes were highly sensitive to the absolute frequency of the DP, and were most prominent at frequencies below 300Hz. Cochlear DPs could thus be effectively masked by low-frequency noise, as expected. Earphone DP amplitudes, in contrast, were highly sensitive to both stimulus and DP frequency (due to prominent resonances in the earphone's transfer function), and their levels grew more rapidly with increasing stimulus level than did cochlear DP amplitudes. As a result, earphone DP amplitudes often exceeded those of cochlear DPs. Using fMRI, we found that earphone DPs had a substantial effect on the response of pitch-sensitive cortical regions. In contrast, cochlear DPs had a small effect on cortical fMRI responses that did not reach statistical significance, consistent with their lower amplitudes. Based on these findings, we designed a set of pitch stimuli optimized for identifying pitch-responsive brain regions using fMRI. These stimuli robustly drive pitch-responsive brain regions while producing minimal cochlear and earphone distortion, and will hopefully aid fMRI

  12. Intracranial artery velocity measurement using 4D PC MRI at 3 T: comparison with transcranial ultrasound techniques and 2D PC MRI

    Energy Technology Data Exchange (ETDEWEB)

    Meckel, Stephan [University Hospital Freiburg, Department of Neuroradiology, Freiburg (Germany); Leitner, Lorenz; Schubert, Tilman [University Hospital Basel, Institute of Radiology, Basel (Switzerland); Bonati, Leo H.; Lyrer, Philippe [University Hospital Basel, Department of Neurology, Basel (Switzerland); Santini, Francesco [University Hospital Basel, Department of Radiological Physics, Institute of Radiology, Basel (Switzerland); Stalder, Aurelien F. [Xuanwu Hospital - Capital Medical University, Department of Radiology, Beijing (China); Markl, Michael [Northwestern University Feinberg School of Medicine, Departments of Radiology and Biomedical Engineering, Chicago (United States); Wetzel, Stephan G. [Neuroradiology, Swiss Neuro Institute, Klinik Hirslanden, Zurich (Switzerland)

    2013-04-15

    4D phase contrast MR imaging (4D PC MRI) has been introduced for spatiotemporal evaluation of intracranial hemodynamics in various cerebrovascular diseases. However, it still lacks validation with standards of reference. Our goal was to compare blood flow quantification derived from 4D PC MRI with transcranial ultrasound and 2D PC MRI. Velocity measurements within large intracranial arteries [internal carotid artery (ICA), basilar artery (BA), and middle cerebral artery (MCA)] were obtained in 20 young healthy volunteers with 4D and 2D PC MRI, transcranial Doppler sonography (TCD), and transcranial color-coded duplex sonography (TCCD). Maximum velocities at peak systole (PSV) and end diastole (EDV) were compared using regression analysis and Bland-Altman plots. Correlation of 4D PC MRI measured velocities was higher in comparison with TCD (r = 0.49-0.66) than with TCCD (0.35-0.44) and 2D PC MRI (0.52-0.60). In mid-BA and ICA C7 segment, a significant correlation was found with TCD (0.68-0.81 and 0.65-0.71, respectively). No significant correlation was found in carotid siphon. On average over all volunteers, PSVs and EDVs in MCA were minimally underestimated compared with TCD/TCCD. Minimal overestimation of velocities was found compared to TCD in mid-BA and ICA C7 segment. 4D PC MRI appears as valid alternative for intracranial velocity measurement consistent with previous reference standards, foremost with TCD. Spatiotemporal averaging effects might contribute to vessel size-dependent mild underestimation of velocities in smaller (MCA), and overestimation in larger-sized (BA and ICA) arteries, respectively. Complete spatiotemporal flow analysis may be advantageous in anatomically complex regions (e.g. carotid siphon) relative to restrictions of ultrasound techniques. (orig.)

  13. Intracranial artery velocity measurement using 4D PC MRI at 3 T: comparison with transcranial ultrasound techniques and 2D PC MRI

    International Nuclear Information System (INIS)

    4D phase contrast MR imaging (4D PC MRI) has been introduced for spatiotemporal evaluation of intracranial hemodynamics in various cerebrovascular diseases. However, it still lacks validation with standards of reference. Our goal was to compare blood flow quantification derived from 4D PC MRI with transcranial ultrasound and 2D PC MRI. Velocity measurements within large intracranial arteries [internal carotid artery (ICA), basilar artery (BA), and middle cerebral artery (MCA)] were obtained in 20 young healthy volunteers with 4D and 2D PC MRI, transcranial Doppler sonography (TCD), and transcranial color-coded duplex sonography (TCCD). Maximum velocities at peak systole (PSV) and end diastole (EDV) were compared using regression analysis and Bland-Altman plots. Correlation of 4D PC MRI measured velocities was higher in comparison with TCD (r = 0.49-0.66) than with TCCD (0.35-0.44) and 2D PC MRI (0.52-0.60). In mid-BA and ICA C7 segment, a significant correlation was found with TCD (0.68-0.81 and 0.65-0.71, respectively). No significant correlation was found in carotid siphon. On average over all volunteers, PSVs and EDVs in MCA were minimally underestimated compared with TCD/TCCD. Minimal overestimation of velocities was found compared to TCD in mid-BA and ICA C7 segment. 4D PC MRI appears as valid alternative for intracranial velocity measurement consistent with previous reference standards, foremost with TCD. Spatiotemporal averaging effects might contribute to vessel size-dependent mild underestimation of velocities in smaller (MCA), and overestimation in larger-sized (BA and ICA) arteries, respectively. Complete spatiotemporal flow analysis may be advantageous in anatomically complex regions (e.g. carotid siphon) relative to restrictions of ultrasound techniques. (orig.)

  14. Improved Technique for Measurement of Regional Fractional Ventilation by Hyperpolarized 3He MRI

    OpenAIRE

    Emami, Kiarash; Kadlecek, Stephen J.; Woodburn, John M.; Zhu, Jianliang; Yu, Jiangsheng; Vahdat, Vahid; Pickup, Stephen; Ishii, Masaru; Rizi, Rahim R.

    2010-01-01

    Quantitative measurement of regional lung ventilation is of great significance in assessment of lung function in many obstructive and restrictive pulmonary diseases. A new technique for regional measurement of fractional ventilation using hyperpolarized 3He MRI is proposed, addressing the shortcomings of an earlier approach that limited its use to small animals. The new approach allows for the acquisition of similar quantitative maps over a shortened period and requires substantially less 3He...

  15. Dorso-Lateral Prefrontal Cortex MRI Measurements and Cognitive Performance in Autism

    OpenAIRE

    Griebling, Jessica; Minshew, Nancy J.; Bodner, Kimberly; Libove, Robin; Bansal, Rahul; Konasale, Prasad; Keshavan, Matcheri S; Hardan, Antonio

    2010-01-01

    This study examined the relationships between volumetric measurements of frontal lobe structures and performance on executive function tasks in individuals with autism. MRI scans were obtained from 38 individuals with autism and 40 matched controls between the ages of 8 and 45 years. Executive function was assessed using neuropsychological measures including the Wisconsin Card Sorting Test and Tower of Hanoi. Differences in performance on the neuropsychological tests were found between the tw...

  16. Mapping three-dimensional oil distribution with π-EPI MRI measurements at low magnetic field

    Science.gov (United States)

    Li, Ming; Xiao, Dan; Romero-Zerón, Laura; Marica, Florea; MacMillan, Bryce; Balcom, Bruce J.

    2016-08-01

    Magnetic resonance imaging (MRI) is a robust tool to image oil saturation distribution in rock cores during oil displacement processes. However, a lengthy measurement time for 3D measurements at low magnetic field can hinder monitoring the displacement. 1D and 2D MRI measurements are instead often undertaken to monitor the oil displacement since they are faster. However, 1D and 2D images may not completely reflect the oil distribution in heterogeneous rock cores. In this work, a high-speed 3D MRI technique, π Echo Planar Imaging (π-EPI), was employed at 0.2 T to monitor oil displacement. Centric scan interleaved sampling with view sharing in k-t space was employed to improve the temporal resolution of the π-EPI measurements. A D2O brine was employed to distinguish the hydrocarbon and water phases. A relatively homogenous glass bead pack and a heterogeneous Spynie core plug were employed to show different oil displacement behaviors. High quality 3D images were acquired with π-EPI MRI measurements. Fluid quantification with π-EPI compared favorably with FID, CPMG, 1D-DHK-SPRITE, 3D Fast Spin Echo (FSE) and 3D Conical SPRITE measurements. π-EPI greatly reduced the gradient duty cycle and improved sensitivity, compared to FSE and Conical SPRITE measurements, enabling dynamic monitoring of oil displacement processes. For core plug samples with sufficiently long lived T2, T2∗, π-EPI is an ideal method for rapid 3D saturation imaging.

  17. MRI markers for mild cognitive impairment: comparisons between white matter integrity and gray matter volume measurements.

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    Full Text Available The aim of the study was to evaluate the value of assessing white matter integrity using diffusion tensor imaging (DTI for classification of mild cognitive impairment (MCI and prediction of cognitive impairments in comparison to brain atrophy measurements using structural MRI. Fifty-one patients with MCI and 66 cognitive normal controls (CN underwent DTI and T1-weighted structural MRI. DTI measures included fractional anisotropy (FA and radial diffusivity (DR from 20 predetermined regions-of-interest (ROIs in the commissural, limbic and association tracts, which are thought to be involved in Alzheimer's disease; measures of regional gray matter (GM volume included 21 ROIs in medial temporal lobe, parietal cortex, and subcortical regions. Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex. Group classifications based on FA or DR was significant and better than classifications based on GM volume. Using either DR or FA together with GM volume improved classification accuracy. Furthermore, all three measures, FA, DR and GM volume were similarly accurate in predicting cognitive performance in MCI patients. Taken together, the results imply that DTI measures are as accurate as measures of GM volume in detecting brain alterations that are associated with cognitive impairment. Furthermore, a combination of DTI and structural MRI measurements improves classification accuracy.

  18. Occupational exposure measurements of static and pulsed gradient magnetic fields in the vicinity of MRI scanners

    International Nuclear Information System (INIS)

    Recent advances in magnetic resonance imaging (MRI) have increased occupational exposure to magnetic fields. In this study, we examined the assessment of occupational exposure to gradient magnetic fields and time-varying magnetic fields generated by motion in non-homogeneous static magnetic fields of MRI scanners. These magnetic field components can be measured simultaneously with an induction coil setup that detects the time rate of change of magnetic flux density (dB/dt). The setup developed was used to measure the field components around two MRI units (1 T open and 3 T conventional). The measured values can be compared with dB/dt reference levels derived from magnetic flux density reference levels given by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). The measured motion-induced dB/dt values were above the dB/dt reference levels for both MRI units. The measured values for the gradient fields (echo planar imaging (EPI) and fast field echo (FFE) sequences) also exceeded the dB/dt reference levels in positions where the medical staff may have access during interventional procedures. The highest motion-induced dB/dt values were 0.7 T s-1 for the 1 T scanner and 3 T s-1 for the 3 T scanner when only the static field was present. Even higher values (6.5 T s-1) were measured for simultaneous exposure to motion-induced and gradient fields in the vicinity of the 3 T scanner.

  19. In vivo MRI volumetric measurement of prostate regression and growth in mice

    Directory of Open Access Journals (Sweden)

    Nalcioglu Orhan

    2007-07-01

    Full Text Available Abstract Background Mouse models for treatment of late-stage prostate cancer are valuable tools, but assessing the extent of growth of the prostate and particularly its regression due to therapeutic intervention or castration is difficult due to the location, small size and interdigitated anatomy of the prostate gland in situ. Temporal monitoring of mouse prostate regression requires multiple animals and examination of histological sections. Methods Initially, T2-weighted magnetic resonance imaging (MRI was performed on normal year-old C57/BL6 mice. Individual mice were repeatedly imaged using inhalation anesthesia to establish the reproducibility of the method and to follow hormone manipulation of the prostate volume. Subsequently, MRI fat signal was suppressed using a chemical shift-selective (CHESS pulse to avoid signal contamination and enhance discrimination of the prostate. Results High field (7T MRI provides high resolution (117 × 117 μm in plane, highly reproducible images of the normal mouse prostate. Despite long imaging times, animals can be imaged repeatedly to establish reliability of volume measurements. Prostate volume declines following castration and subsequently returns to normal with androgen administration in the same animal. CHESS imaging allowed discrimination of both the margins of the prostate and the dorsal-lateral lobes of the prostate (DLP from the ventral lobes (VP. Castration results in a 40% reduction in the volume of the DLP and a 75% reduction in the volume of the VP. Conclusion MRI assessment of the volume of the mouse prostate is precise and reproducible. MRI improves volumetric determination of the extent of regression and monitoring of the same mouse over time during the course of treatment is possible. Since assessing groups of animals at each time point is avoided, this improves the accuracy of the measurement of any manipulation effect and reduces the number of animals required.

  20. Subtle in-scanner motion biases automated measurement of brain anatomy from in vivo MRI.

    Science.gov (United States)

    Alexander-Bloch, Aaron; Clasen, Liv; Stockman, Michael; Ronan, Lisa; Lalonde, Francois; Giedd, Jay; Raznahan, Armin

    2016-07-01

    While the potential for small amounts of motion in functional magnetic resonance imaging (fMRI) scans to bias the results of functional neuroimaging studies is well appreciated, the impact of in-scanner motion on morphological analysis of structural MRI is relatively under-studied. Even among "good quality" structural scans, there may be systematic effects of motion on measures of brain morphometry. In the present study, the subjects' tendency to move during fMRI scans, acquired in the same scanning sessions as their structural scans, yielded a reliable, continuous estimate of in-scanner motion. Using this approach within a sample of 127 children, adolescents, and young adults, significant relationships were found between this measure and estimates of cortical gray matter volume and mean curvature, as well as trend-level relationships with cortical thickness. Specifically, cortical volume and thickness decreased with greater motion, and mean curvature increased. These effects of subtle motion were anatomically heterogeneous, were present across different automated imaging pipelines, showed convergent validity with effects of frank motion assessed in a separate sample of 274 scans, and could be demonstrated in both pediatric and adult populations. Thus, using different motion assays in two large non-overlapping sets of structural MRI scans, convergent evidence showed that in-scanner motion-even at levels which do not manifest in visible motion artifact-can lead to systematic and regionally specific biases in anatomical estimation. These findings have special relevance to structural neuroimaging in developmental and clinical datasets, and inform ongoing efforts to optimize neuroanatomical analysis of existing and future structural MRI datasets in non-sedated humans. Hum Brain Mapp 37:2385-2397, 2016. © 2016 Wiley Periodicals, Inc. PMID:27004471

  1. Cerebrospinal fluid volumetric MRI mapping as a simple measurement for evaluating brain atrophy

    International Nuclear Information System (INIS)

    To assess whether volumetric cerebrospinal fluid (CSF) MRI can be used as a surrogate for brain atrophy assessment and to evaluate how the T2 of the CSF relates to brain atrophy. Twenty-eight subjects [mean age 64 (sd 2) years] were included; T1-weighted and CSF MRI were performed. The first echo data of the CSF MRI sequence was used to obtain intracranial volume, CSF partial volume was measured voxel-wise to obtain CSF volume (VCSF) and the T2 of CSF (T2,CSF) was calculated. The correlation between VCSF / T2,CSF and brain atrophy scores [global cortical atrophy (GCA) and medial temporal lobe atrophy (MTA)] was evaluated. Relative total, peripheral subarachnoidal, and ventricular VCSF increased significantly with increased scores on the GCA and MTA (R = 0.83, 0.78 and 0.78 and R = 0.72, 0.62 and 0.86). Total, peripheral subarachnoidal, and ventricular T2 of the CSF increased significantly with higher scores on the GCA and MTA (R = 0.72, 0.70 and 0.49 and R = 0.60, 0.57 and 0.41). A fast, fully automated CSF MRI volumetric sequence is an alternative for qualitative atrophy scales. The T2 of the CSF is related to brain atrophy and could thus be a marker of neurodegenerative disease. (orig.)

  2. Cerebrospinal fluid volumetric MRI mapping as a simple measurement for evaluating brain atrophy

    Energy Technology Data Exchange (ETDEWEB)

    Vis, J.B. de; Zwanenburg, J.J.; Kleij, L.A. van der; Spijkerman, J.M.; Hendrikse, J. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Biessels, G.J. [University Medical Center Utrecht, Department of Neurology, Brain Center Rudolf Magnus, Utrecht (Netherlands); Petersen, E.T. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Hvidovre Hospital, Danish Research Centre for Magnetic Resonance, Hvidovre (Denmark)

    2016-05-15

    To assess whether volumetric cerebrospinal fluid (CSF) MRI can be used as a surrogate for brain atrophy assessment and to evaluate how the T{sub 2} of the CSF relates to brain atrophy. Twenty-eight subjects [mean age 64 (sd 2) years] were included; T{sub 1}-weighted and CSF MRI were performed. The first echo data of the CSF MRI sequence was used to obtain intracranial volume, CSF partial volume was measured voxel-wise to obtain CSF volume (V{sub CSF}) and the T{sub 2} of CSF (T{sub 2,CSF}) was calculated. The correlation between V{sub CSF} / T{sub 2,CSF} and brain atrophy scores [global cortical atrophy (GCA) and medial temporal lobe atrophy (MTA)] was evaluated. Relative total, peripheral subarachnoidal, and ventricular V{sub CSF} increased significantly with increased scores on the GCA and MTA (R = 0.83, 0.78 and 0.78 and R = 0.72, 0.62 and 0.86). Total, peripheral subarachnoidal, and ventricular T{sub 2} of the CSF increased significantly with higher scores on the GCA and MTA (R = 0.72, 0.70 and 0.49 and R = 0.60, 0.57 and 0.41). A fast, fully automated CSF MRI volumetric sequence is an alternative for qualitative atrophy scales. The T{sub 2} of the CSF is related to brain atrophy and could thus be a marker of neurodegenerative disease. (orig.)

  3. Measurement of MRI scanner noise; Schalldruckpegelmessungen an einer MRT-Anlage

    Energy Technology Data Exchange (ETDEWEB)

    Knoergen, M.; Spielmann, R.P.; Melkus, G. [Klinik fuer Diagnostische Radiologie, Klinikum der Martin-Luther-Univ. Halle-Wittenberg (Germany); Haberland, E.J. [Klinik fuer Hals-, Nasen-, Ohrenheilkunde, Kopf- und Halschirurgie, Klinikum der Martin-Luther-Univ. Halle-Wittenberg (Germany)

    2004-07-01

    The present paper describes a simple method for the analysis of MRI scanner noise. Besides the heating of body tissue by strong RF radiation and the formation of circular currents in the body induced bey switching field gradients, a noise level of more than 100 dB(A) during the measurement belongs to the potential risks of MRI [1,2]. This risk is of particular concern for staff and accompanying persons who remain close to the scanner for different reasons (e.g., monitoring of anesthetized patients, reassuring of children). For this reason, and given the scanty information on noise provided in the manuals of the scanners, it is useful to quantify the noise level more exactly. This applies also to the evaluation of different sound-reducing methods for the patient. This presents the results of noise level measurements in the tomograph and in its surrounding, with and without noise reduction by headphones. (orig.)

  4. A quick and robust method for measurement of signal-to-noise ratio in MRI

    International Nuclear Information System (INIS)

    A novel method is proposed for the measurement of signal-to-noise ratio (SNR) for the purpose of quality assurance (QA) in MRI. A boxcar filtering technique is applied which allows estimation of signal and noise from a single image. The method has been used to estimate SNR in a large set of images acquired in a consistent manner using various scanner models, coils and phantoms. Performance is evaluated by comparison with the double-image subtraction technique incorporating temporal instability correction. The limits of agreement between the techniques are comparable to typical variability in daily SNR, and significantly superior to the performance of other single-image methods published to date. Single-image methods are preferable as they halve the image acquisition time of the recommended double-image approach. Major inaccuracies are identified in methods of SNR measurement currently used for QA in MRI. (paper)

  5. Quantitative measurement of cerebral oxygen extraction fraction using MRI in patients with MELAS.

    Directory of Open Access Journals (Sweden)

    Lei Yu

    Full Text Available OBJECTIVE: To quantify the cerebral OEF at different phases of stroke-like episodes in patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS by using MRI. METHODS: We recruited 32 patients with MELAS confirmed by gene analysis. Conventional MRI scanning, as well as functional MRI including arterial spin labeling and oxygen extraction fraction imaging, was undertaken to obtain the pathological and metabolic information of the brains at different stages of stroke-like episodes in patients. A total of 16 MRI examinations at the acute and subacute phase and 19 examinations at the interictal phase were performed. In addition, 24 healthy volunteers were recruited for control subjects. Six regions of interest were placed in the anterior, middle, and posterior parts of the bilateral hemispheres to measure the OEF of the brain or the lesions. RESULTS: OEF was reduced significantly in brains of patients at both the acute and subacute phase (0.266 ± 0.026 and at the interictal phase (0.295 ± 0.009, compared with normal controls (0.316 ± 0.025. In the brains at the acute and subacute phase of the episode, 13 ROIs were prescribed on the stroke-like lesions, which showed decreased OEF compared with the contralateral spared brain regions. Increased blood flow was revealed in the stroke-like lesions at the acute and subacute phase, which was confined to the lesions. CONCLUSION: MRI can quantitatively show changes in OEF at different phases of stroke-like episodes. The utilization of oxygen in the brain seems to be reduced more severely after the onset of episodes in MELAS, especially for those brain tissues involved in the episodes.

  6. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan; Fiehler, Jens [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neuroradiology; Reitz, Matthias; Schmidt, Nils O. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neurosurgery; Bolar, Divya S. [Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States). Radiology; Adalsteinsson, Elfar [Massachusetts Institute of Technology, Cambridge, MA (United States). Electrical Engineering and Computer Science

    2015-05-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s {sup and} -1] = 20.7/20.4/20.1, R2*[s {sup and} -1] = 31.6/29.6/25.9, R2'[s {sup and} 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min {sup and} -1.100g {sup and} -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood

  7. On the comparison between MRI and US imaging for human heel pad thickness measurements

    DEFF Research Database (Denmark)

    Matteoli, Sara; Corbin, Nadège Corbin; Wilhjelm, Jens E.; Torp-Pedersen, Søren T.

    2011-01-01

    thickness as they are both ionizing-free radiations. The aim of this paper is to measure the bone to skin distance of nine heel pad phantoms from MRI and US images, and to compare the results with a true value (TV) in order to find the errors. Paired sample t-test was used to compare the measurements......1530 (P-value=0.402). Results confirm the necessity to investigate on the real speed of sound for the heel pad tissues, in order to have realistic measurements when dealing with human heel pads. __________________________________________________________________________________________________________...

  8. A proposal for PET/MRI attenuation correction with μ-values measured using a fixed-position radiation source and MRI segmentation

    Energy Technology Data Exchange (ETDEWEB)

    Kawaguchi, Hiroshi, E-mail: kwgc@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Hirano, Yoshiyuki, E-mail: yhirano@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yoshida, Eiji, E-mail: rush@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Kershaw, Jeff, E-mail: len@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Shiraishi, Takahiro, E-mail: tshira@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Suga, Mikio, E-mail: mikio.suga@faculty.chiba-u.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Engineering of Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Ikoma, Yoko, E-mail: ikoma@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Obata, Takayuki, E-mail: t_obata@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Ito, Hiroshi, E-mail: hito@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Yamaya, Taiga, E-mail: taiga@nirs.go.jp [Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2014-01-11

    Several MRI-based attenuation correction methods have been reported for PET/MRI; these methods are expected to make efficient use of high-quality anatomical MRIs and reduce the radiation dose for PET/MRI scanning. The accuracy of the attenuation map (μ-map) from an MRI depends on the accuracy of tissue segmentation and the attenuation coefficients to be assigned (μ-values). In this study, we proposed an MRI-based μ-value estimation method with a non-rotational radiation source to construct a suitable μ-map for PET/MRI. The proposed method uses an accurately segmented tissue map, the partial path length of each tissue, and detected intensities of attenuated radiation from a fixed-position (rather than a rotating) radiation source to obtain the μ-map. We estimated the partial path length from a virtual blank scan of fixed-point radiation with the same scanner geometry using the known tissue map from MRI. The μ-values of every tissue were estimated by inverting a linear relationship involving the partial path lengths and measured radioactivity intensity. Validation of the proposed method was performed by calculating a fixed- point data set based upon real a real transmission scan. The root-mean-square error between the μ-values derived from a conventional transmission scan and those obtained with our proposed method were 2.4±1.4%, 17.4±9.1% and 6.6±4.3% for brain, bone and soft tissue other than brain, respectively. Although the error estimates for bone and soft tissue are not insignificant, the method we propose is able to estimate the brain μ-value accurately and it is this factor that most strongly affects the quantitative value of PET images because of the large volumetric ratio of the brain. -- Highlights: • An MRI-derived µ-map for the attenuation correction of PET images is proposed. • Method relies on segmentation of MRI and a fixed-point source transmission scan. • Tissue segmentation reduces the number of unknown µ-values. • Method

  9. Tumour size measurement in a mouse model using high resolution MRI

    International Nuclear Information System (INIS)

    Animal models are frequently used to assess new treatment methods in cancer research. MRI offers a non-invasive in vivo monitoring of tumour tissue and thus allows longitudinal measurements of treatment effects, without the need for large cohorts of animals. Tumour size is an important biomarker of the disease development, but to our knowledge, MRI based size measurements have not yet been verified for small tumours (10−2–10−1 g). The aim of this study was to assess the accuracy of MRI based tumour size measurements of small tumours on mice. 2D and 3D T2-weighted RARE images of tumour bearing mice were acquired in vivo using a 7 T dedicated animal MR system. For the 3D images the acquired image resolution was varied. The images were exported to a PC workstation where the tumour mass was determined assuming a density of 1 g/cm3, using an in-house developed tool for segmentation and delineation. The resulting data were compared to the weight of the resected tumours after sacrifice of the animal using regression analysis. Strong correlations were demonstrated between MRI- and necropsy determined masses. In general, 3D acquisition was not a prerequisite for high accuracy. However, it was slightly more accurate than 2D when small (<0.2 g) tumours were assessed for inter- and intraobserver variation. In 3D images, the voxel sizes could be increased from 1603 μm3 to 2403 μm3 without affecting the results significantly, thus reducing acquisition time substantially. 2D MRI was sufficient for accurate tumour size measurement, except for small tumours (<0.2 g) where 3D acquisition was necessary to reduce interobserver variation. Acquisition times between 15 and 50 minutes, depending on tumour size, were sufficient for accurate tumour volume measurement. Hence, it is possible to include further MR investigations of the tumour, such as tissue perfusion, diffusion or metabolic composition in the same MR session

  10. Ischiofemoral space on MRI in an asymptomatic population: Normative width measurements and soft tissue signal variations

    Energy Technology Data Exchange (ETDEWEB)

    Maras Oezdemir, Zeynep; Goermeli, Cemile Ayse; Sagir Kahraman, Ayseguel [Inoenue University School of Medicine, Department of Radiology, Malatya (Turkey); Aydingoez, Uestuen [Hacettepe University School of Medicine, Department of Radiology, Ankara (Turkey)

    2015-08-15

    To make normative width measurements of the ischiofemoral (IF) space in an asymptomatic population and to record soft tissue MRI signal variations within the IF space in order to determine whether such variations are associated with IF space dimensions. Normative width measurements of the IF space were prospectively made in 418 hips on 1.5 T MR images of 209 asymptomatic volunteers. Quantitative and qualitative assessments of the IF soft tissues including the quadratus femoris (QF) muscle were also made. The mean IF space width was 2.56 ± 0.75 cm (right, 2.60 ± 0.75 cm; left, 2.53 ± 0.75 cm). Soft tissue MRI signal abnormalities were present within the IF space in 19 (9.1 %) of 209 volunteers. Soft tissue abnormalities within the IF space included oedema (3/209, 1.4 %) of the QF and/or surrounding soft tissue, and only fatty infiltration (16/209, 7.7 %) of the QF. Bilateral IF spaces are asymmetrical in asymptomatic persons. There is ≥10 % of width difference between right and left IF spaces in approximately half of asymptomatic individuals. Fatty infiltration and oedema can be present at the IF space in a small portion of the asymptomatic population, who also have narrower IF spaces than those without soft tissue MRI signal abnormalities. (orig.)

  11. 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.

  12. Carotid intima-media thickness and distensibility measured by MRI at 3 T versus high-resolution ultrasound

    International Nuclear Information System (INIS)

    We evaluated an MRI protocol at 3 T for the assessment of morphological and functional properties of the common carotid artery (CCA) in 32 healthy volunteers and 20 patients with high-grade internal carotid artery stenosis. Wall thickness of the CCA was measured by using multislice 2D T2 dark blood fast spin echo sequences and compared with intima-media thickness (IMT) determined by ultrasound. Carotid distensibility coefficient (DC) quantified by blood pressure and CCA diameter change during the cardiac cycle was measured by ECG gated 3D T1 CINE MRI and M-mode ultrasound. Apart from generally higher values in MRI high agreement was found for wall thickness and compliance in volunteers and patients. Remaining differences between both methods may be attributed to slightly different methods for measuring IMT and DC. Our findings indicate that MRI at 3 T is a feasible and promising tool for the comprehensive assessment of normal carotid geometry and function. (orig.)

  13. Cardiac MRI in pulmonary artery hypertension: correlations between morphological and functional parameters and invasive measurements

    International Nuclear Information System (INIS)

    To compare cardiac MRI with right heart catheterisation in patients with pulmonary hypertension (PH) and to evaluate its ability to assess PH severity. Forty patients were included. MRI included cine and phase-contrast sequences, study of ventricular function, cardiac cavity areas and ratios, position of the interventricular septum (IVS) in systole and diastole, and flow measurements. We defined four groups according to the severity of PH and three groups according to IVS position: A, normal position; B, abnormal in diastole; C, abnormal in diastole and systole. IVS position was correlated with pulmonary artery pressures and PVR (pulmonary vascular resistance). Median pulmonary artery pressures and resistance were significantly higher in patients with an abnormal septal position compared with those with a normal position. Correlations were good between the right ventricular ejection fraction and PVR, right ventricular end-systolic volume and PAP, percentage of right ventricular area change and PVR, and diastolic and systolic ventricular area ratio and PVR. These parameters were significantly associated with PH severity. Cardiac MRI can help to assess the severity of PH. (orig.)

  14. Measurement of Strain in the Left Ventricle during Diastole withcine-MRI and Deformable Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Veress, Alexander I.; Gullberg, Grant T.; Weiss, Jeffrey A.

    2005-07-20

    The assessment of regional heart wall motion (local strain) can localize ischemic myocardial disease, evaluate myocardial viability and identify impaired cardiac function due to hypertrophic or dilated cardiomyopathies. The objectives of this research were to develop and validate a technique known as Hyperelastic Warping for the measurement of local strains in the left ventricle from clinical cine-MRI image datasets. The technique uses differences in image intensities between template (reference) and target (loaded) image datasets to generate a body force that deforms a finite element (FE) representation of the template so that it registers with the target image. To validate the technique, MRI image datasets representing two deformation states of a left ventricle were created such that the deformation map between the states represented in the images was known. A beginning diastoliccine-MRI image dataset from a normal human subject was defined as the template. A second image dataset (target) was created by mapping the template image using the deformation results obtained from a forward FE model of diastolic filling. Fiber stretch and strain predictions from Hyperelastic Warping showed good agreement with those of the forward solution. The technique had low sensitivity to changes in material parameters, with the exception of changes in bulk modulus of the material. The use of an isotropic hyperelastic constitutive model in the Warping analyses degraded the predictions of fiber stretch. Results were unaffected by simulated noise down to an SNR of 4.0. This study demonstrates that Warping in conjunction with cine-MRI imaging can be used to determine local ventricular strains during diastole.

  15. Accuracy of MRI technique in measuring tendon cross-sectional area

    DEFF Research Database (Denmark)

    Couppé, Christian; Svensson, R. B.; Elbrønd (Bibs), Vibeke Sødring;

    2014-01-01

    accuracy in relation to actual tendon dimensions has never been investigated. The purpose of this study was to compare tendon CSA measured by MRI with that measured in vitro with the mould casting technique. The knee of a horse was MRI-scanned with 1.5 and 3 tesla, and two examiners measured the patellar...... tendon CSA. Thereafter, the patellar tendon of the horse was completely dissected and embedded in an alginate cast. The CSA of the embedded tendon was measured directly by optical imaging of the cast impression. 1.5 tesla grey tendon CSA and 3 tesla grey tendon CSA were 16.5% and 13.2% lower than the...... mould tendon CSA, respectively. Also, 3 tesla tendon CSA, based on the red-green border on the National Institute of Health (NIH) colour scale, was lower than the mould tendon CSA by 2.8%. The typical error between examiners was below 2% for all the measured CSA. The typical error between examiners was...

  16. Cell Treatment for Stroke in Type Two Diabetic Rats Improves Vascular Permeability Measured by MRI.

    Directory of Open Access Journals (Sweden)

    Guangliang Ding

    Full Text Available Treatment of stroke with bone marrow stromal cells (BMSC significantly enhances brain remodeling and improves neurological function in non-diabetic stroke rats. Diabetes is a major risk factor for stroke and induces neurovascular changes which may impact stroke therapy. Thus, it is necessary to test our hypothesis that the treatment of stroke with BMSC has therapeutic efficacy in the most common form of diabetes, type 2 diabetes mellitus (T2DM. T2DM was induced in adult male Wistar rats by administration of a high fat diet in combination with a single intraperitoneal injection (35mg/kg of streptozotocin. These rats were then subjected to 2h of middle cerebral artery occlusion (MCAo. T2DM rats received BMSC (5x106, n = 8 or an equal volume of phosphate-buffered saline (PBS (n = 8 via tail-vein injection at 3 days after MCAo. MRI was performed one day and then weekly for 5 weeks post MCAo for all rats. Compared with vehicle treated control T2DM rats, BMSC treatment of stroke in T2DM rats significantly (p<0.05 decreased blood-brain barrier disruption starting at 1 week post stroke measured using contrast enhanced T1-weighted imaging with gadopentetate, and reduced cerebral hemorrhagic spots starting at 3 weeks post stroke measured using susceptibility weighted imaging, although BMSC treatment did not reduce the ischemic lesion volumes as demarcated by T2 maps. These MRI measurements were consistent with histological data. Thus, BMSC treatment of stroke in T2DM rats initiated at 3 days after stroke significantly reduced ischemic vascular damage, although BMSC treatment did not change infarction volume in T2DM rats, measured by MRI.

  17. Reference values of MRI measurements of the common bile duct and pancreatic duct in children

    Energy Technology Data Exchange (ETDEWEB)

    Gwal, Kriti; Bedoya, Maria A.; Patel, Neal; Darge, Kassa; Anupindi, Sudha A. [University of Pennsylvania Perelman School of Medicine, Department of Radiology, The Children' s Hospital of Philadelphia, Philadelphia, PA (United States); Rambhatla, Siri J. [Beth Israel Medical Center, Department of Pediatrics, Newark, NJ (United States); Sreedharan, Ram R. [University of Pennsylvania, Departments of Gastroenterology, Hepatology and Nutrition, The Children' s Hospital of Philadelphia, Perelman School of Medicine, Philadelphia, PA (United States)

    2015-08-15

    Magnetic resonance imaging/cholangiopancreatography (MRI/MRCP) is now an essential imaging modality for the evaluation of biliary and pancreatic pathology in children, but there are no data depicting the normal diameters of the common bile duct (CBD) and pancreatic duct. Recognition of abnormal duct size is important and the increasing use of MRCP necessitates normal MRI measurements. To present normal MRI measurements for the common bile duct and pancreatic duct in children. In this retrospective study we searched all children ages birth to 10 years in our MR urography (MRU) database from 2006 until 2013. We excluded children with a history of hepatobiliary or pancreatic surgery. We stratified 204 children into five age groups and retrospectively measured the CBD and the pancreatic duct on 2-D axial and 3-D coronal T2-weighted sequences. We performed statistical analysis, using logistic and linear regressions to detect the age association of the visibility and size of the duct measurements. We used non-parametric tests to detect gender and imaging plane differences. Our study included 204 children, 106 (52%) boys and 98 (48%) girls, with a median age of 33 months (range 0-119 months). The children were distributed into five age groups. The common bile duct was visible in all children in all age groups. The pancreatic duct was significantly less visible in the youngest children, group 1 (54/67, 80.5%; P = 0.003) than in the oldest children, group 5 (22/22, 100%). In group 2 the pancreatic duct was seen in 19/21 (90.4%), in group 3 52/55 (94.5%), and in group 4 39/39 (100%). All duct measurements increased with age (P < 0.001; r-value > 0.423), and the incremental differences between ages were significant. The measurement variations between the axial and coronal planes were statistically significant (P < 0.001); however these differences were fractions of millimeters. For example, in group 1 the mean coronal measurement of the CBD was 2.1 mm and the axial

  18. Reference values of MRI measurements of the common bile duct and pancreatic duct in children

    International Nuclear Information System (INIS)

    Magnetic resonance imaging/cholangiopancreatography (MRI/MRCP) is now an essential imaging modality for the evaluation of biliary and pancreatic pathology in children, but there are no data depicting the normal diameters of the common bile duct (CBD) and pancreatic duct. Recognition of abnormal duct size is important and the increasing use of MRCP necessitates normal MRI measurements. To present normal MRI measurements for the common bile duct and pancreatic duct in children. In this retrospective study we searched all children ages birth to 10 years in our MR urography (MRU) database from 2006 until 2013. We excluded children with a history of hepatobiliary or pancreatic surgery. We stratified 204 children into five age groups and retrospectively measured the CBD and the pancreatic duct on 2-D axial and 3-D coronal T2-weighted sequences. We performed statistical analysis, using logistic and linear regressions to detect the age association of the visibility and size of the duct measurements. We used non-parametric tests to detect gender and imaging plane differences. Our study included 204 children, 106 (52%) boys and 98 (48%) girls, with a median age of 33 months (range 0-119 months). The children were distributed into five age groups. The common bile duct was visible in all children in all age groups. The pancreatic duct was significantly less visible in the youngest children, group 1 (54/67, 80.5%; P = 0.003) than in the oldest children, group 5 (22/22, 100%). In group 2 the pancreatic duct was seen in 19/21 (90.4%), in group 3 52/55 (94.5%), and in group 4 39/39 (100%). All duct measurements increased with age (P < 0.001; r-value > 0.423), and the incremental differences between ages were significant. The measurement variations between the axial and coronal planes were statistically significant (P < 0.001); however these differences were fractions of millimeters. For example, in group 1 the mean coronal measurement of the CBD was 2.1 mm and the axial

  19. Histogram analysis of gadoxetic acid-enhanced MRI for quantitative hepatic fibrosis measurement.

    Directory of Open Access Journals (Sweden)

    Honsoul Kim

    Full Text Available The diagnosis and monitoring of liver fibrosis is an important clinical issue; however, this is usually achieved by invasive methods such as biopsy. We aimed to determine whether histogram analysis of hepatobiliary phase images of gadoxetic acid-enhanced magnetic resonance imaging (MRI can provide non-invasive quantitative measurement of liver fibrosis.This retrospective study was approved by the institutional ethics committee, and a waiver of informed consent was obtained. Hepatobiliary phase images of preoperative gadoxetic acid-enhanced MRI studies of 105 patients (69 males, 36 females; age 56.1±12.2 with pathologically documented liver fibrosis grades were analyzed. Fibrosis staging was F0/F1/F2/F3/F4 (METAVIR system for 11/20/13/15/46 patients, respectively. Four regions-of-interest (ROI, each about 2 cm2 were placed on predetermined locations of representative images. The measured signal intensity of pixels in each ROI was used to calculate corrected coefficient of variation (cCV, skewness, and kurtosis. An average value of each parameter was calculated for comparison. Statistical analysis was performed by ANOVA, receiver operating characteristic (ROC curve analysis, and linear regression.The cCV showed statistically significant differences among pathological fibrosis grades (P<0.001 whereas skewness and kurtosis did not. Univariable linear regression analysis suggested cCV to be a meaningful parameter in predicting the fibrosis grade (P<0.001, β = 0.40 and standard error  = 0.06. For discriminating F0-3 from F4, the area under ROC score was 0.857, standard deviation 0.036, 95% confidence interval 0.785-0.928.Histogram analysis of hepatobiliary phase images of gadoxetic acid-enhanced MRI can provide non-invasive quantitative measurements of hepatic fibrosis.

  20. Simultaneous measurement of pulmonary partial pressure of oxygen and apparent diffusion coefficient by hyperpolarized 3He MRI

    OpenAIRE

    Yu, Jiangsheng; Law, Michelle; Kadlecek, Stephen; Emami, Kiarash; Ishii, Masaru; Stephen, Michael; Woodburn, John M.; Vahdat, Vahid; Rizi, Rahim R.

    2009-01-01

    Hyperpolarized 3He (HP 3He) MRI shows promise to assess structural and functional pulmonary parameters in a sensitive, regional and non-invasive way. Structural HP 3He MRI has applied the apparent diffusion coefficient (ADC) for the detection of disease-induced lung microstructure changes at the alveolar level, and HP 3He pulmonary partial pressure of oxygen (pO2) imaging measures the oxygen transfer efficiency between the lung and blood stream. Although both parameters are affected in chroni...

  1. Volume measurement by using super-resolution MRI: application to prostate volumetry

    CERN Document Server

    Oubel, Estanislao; Iannessi, Antoine

    2015-01-01

    Accuracy and precision of measurements are important for patient follow up in oncology but, unfortunately, partial volume effects introduce an undesired variability between observers. Super resolution techniques (SR) combine multiple acquisitions of an object into a single image richer in details. Herein, the use of SR for reducing variability is investigated in the specific context of prostate measurements. Prostate is typically imaged by T2-weighted MRI in three perpendicular low resolution images, each of them presenting partial volume effects in the direction of the slice selection gradient. SR techniques allow to combine these images into an image presenting the same level of details in all directions. This is expected to increase the accuracy and reproducibility of volume measurements, which in turn improves other derived measurements like PSA density.

  2. MRI volume measurement of basal ganglia volumes in patients with Tourette's syndrome

    International Nuclear Information System (INIS)

    Objective: To evaluate MRI measurement of basal ganglia volumes in patients with Tourette's syndrome. Methods: Ten patients with Tourette's syndrome (TS) and 10 healthy volunteers were studied. Volumes of bilateral caudate, putamen and pallidum were measured, and the results were analyzed using paired t test. The basal ganglia volume was normalized according to individual brain volume. The basal ganglia volumes of TS patients were compared with normal control group using independent-sample t test. Results: In 10 healthy volunteers, volumes of the left caudate, putamen, pallidum were significantly larger compared with those of the right side (P0.05) in TS patients. After normalized processing, the volumes of the left caudate (7.06 ± 0.48) cm3, putamen (8.81±1.01) cm3, pallidum (2.64± 0.38) cm3 were smaller than those of control group [caudate (11.05±1.86) cm3, putamen (9.97± 1.11) cm3, pallidum (3.04±0.37) cm3] (t=-6.577, -2.457, -2.376, P3 in TS patients was significantly smaller compared with the control group (9.81±1.83) cm3 (t=-4.258, P0.05). Conclusion: The basal ganglia volumes were significantly decreased in patients with TS. MRI volumetric measurement was an important tool for evaluating pathologic changes of TS. (authors)

  3. Tissue temperature distribution measurement by MRI and laser immunology for cancer treatment

    Science.gov (United States)

    Chen, Yichao; Gnyawali, Surya C.; Wu, Feng; Liu, Hong; Tesiram, Yasvir A.; Abbott, Andrew; Towner, Rheal A.; Chen, Wei R.

    2007-02-01

    In cancer treatment and immune response enhancement research, Magnetic Resonance Imaging (MRI) is an ideal method for non-invasive, three-dimensional temperature measurement. We used a 7.1-Tesla magnetic resonance imager for ex vivo tissues and small animal to determine temperature distribution of target tissue during laser irradiation. The feasibility of imaging is approved with high spatial resolution and high signal-noise- ratio. Tissue-simulating gel phantom gel, biological tissues, and tumor-bearing animals were used in the experiments for laser treatment and MR imaging. Thermal couple measurement of temperature in target samples was used for system calibration. An 805-nm laser was used to irradiate the samples with a laser power in the range of 1 to 2.5 watts. Using the MRI system and a specially developed processing algorithm, a clear temperature distribution matrix in the target tissue and surrounding tissue was obtained. The temperature profiles show that the selective laser photothermal effect could result in tissue temperature elevation in a range of 10 to 45 °C. The temperature resolution of the measurement was about 0.37°C including the total system error. The spatial resolution was 0.4 mm (128x128 pixels with field of view of 5.5x5.5 cm). The temperature distribution provided in vivo thermal information and future reference for optimizing dye concentration and irradiation parameters to achieve optimal thermal effects in cancer treatment.

  4. Measurement of anteversion of the femoral neck in children by MRI and evaluation by comparison with CT and ultrasound

    International Nuclear Information System (INIS)

    Anteversion of the femoral neck was measured by MRI in 19 children (37 hips) preoperatively before femoral rotation osteotomies. The results of this new technique were compared with values for anteversion obtained by CT and ultrasound. The measurements were performed independently by two observers to determine the correlation between the three different methods and to assess their reliability. It was possible to show a high correlation coefficient (Pearson) between MRI and CT (r=0.77) as well as MRI and sonography (r=0.81). The mean angles obtained by CT (34 degrees, range +5 to +82 degrees) and ultrasound (25.6 degrees, range +10 to +40 degrees) appeared larger than the MRI values (mean angle 23.2 degrees, range 0 to +65 degrees), which can be explained by the different measurement techniques. Mean inter- and intra-variability was low for MRI (r=0.97 and r=0.97) and CT (r=0.99 and r=0.96) but slightly higher for sonography (r=0.88 and r=0.88). MRI is a new reliable and precise method to evaluate femoral anteversion that does not require ionising radiation. (orig./MG)

  5. Turbulent Kinetic Energy Measurement Using Phase Contrast MRI for Estimating the Post-Stenotic Pressure Drop: In Vitro Validation and Clinical Application.

    Directory of Open Access Journals (Sweden)

    Hojin Ha

    Full Text Available Although the measurement of turbulence kinetic energy (TKE by using magnetic resonance imaging (MRI has been introduced as an alternative index for quantifying energy loss through the cardiac valve, experimental verification and clinical application of this parameter are still required.The goal of this study is to verify MRI measurements of TKE by using a phantom stenosis with particle image velocimetry (PIV as the reference standard. In addition, the feasibility of measuring TKE with MRI is explored.MRI measurements of TKE through a phantom stenosis was performed by using clinical 3T MRI scanner. The MRI measurements were verified experimentally by using PIV as the reference standard. In vivo application of MRI-driven TKE was explored in seven patients with aortic valve disease and one healthy volunteer. Transvalvular gradients measured by MRI and echocardiography were compared.MRI and PIV measurements of TKE are consistent for turbulent flow (0.666 400. The turbulence pressure drop correlates strongly with total TKE (R2 = 0.986. However, in vivo measurements of TKE are not consistent with the transvalvular pressure gradient estimated by echocardiography.These results suggest that TKE measurement via MRI may provide a potential benefit as an energy-loss index to characterize blood flow through the aortic valve. However, further clinical studies are necessary to reach definitive conclusions regarding this technique.

  6. Turbulent Kinetic Energy Measurement Using Phase Contrast MRI for Estimating the Post-Stenotic Pressure Drop: In Vitro Validation and Clinical Application

    Science.gov (United States)

    Ha, Hojin; Kim, Guk Bae; Kweon, Jihoon; Huh, Hyung Kyu; Lee, Sang Joon; Koo, Hyun Jung; Kang, Joon-Won; Lim, Tae-Hwan; Kim, Dae-Hee; Kim, Young-Hak

    2016-01-01

    Background Although the measurement of turbulence kinetic energy (TKE) by using magnetic resonance imaging (MRI) has been introduced as an alternative index for quantifying energy loss through the cardiac valve, experimental verification and clinical application of this parameter are still required. Objectives The goal of this study is to verify MRI measurements of TKE by using a phantom stenosis with particle image velocimetry (PIV) as the reference standard. In addition, the feasibility of measuring TKE with MRI is explored. Methods MRI measurements of TKE through a phantom stenosis was performed by using clinical 3T MRI scanner. The MRI measurements were verified experimentally by using PIV as the reference standard. In vivo application of MRI-driven TKE was explored in seven patients with aortic valve disease and one healthy volunteer. Transvalvular gradients measured by MRI and echocardiography were compared. Results MRI and PIV measurements of TKE are consistent for turbulent flow (0.666 400). The turbulence pressure drop correlates strongly with total TKE (R2 = 0.986). However, in vivo measurements of TKE are not consistent with the transvalvular pressure gradient estimated by echocardiography. Conclusions These results suggest that TKE measurement via MRI may provide a potential benefit as an energy-loss index to characterize blood flow through the aortic valve. However, further clinical studies are necessary to reach definitive conclusions regarding this technique. PMID:26978529

  7. Accurate perioperative flow measurement of the portal vein and hepatic and renal artery: A role for preoperative MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, Mechteld A.R., E-mail: mar.vermeulen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Ligthart-Melis, Gerdien C., E-mail: g.ligthart-melis@vumc.nl [Department of Internal Medicine, Dietetics and Nutritional Sciences, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Buijsman, René, E-mail: renebuysman@gmail.com [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Siroen, Michiel P.C., E-mail: m.siroen6@upcmail.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Poll, Marcel C.G. van de, E-mail: mcg.vandepoll@ah.unimaas.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Boelens, Petra G., E-mail: p.boelens@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Dejong, Cornelis H.C., E-mail: chc.dejong@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Schaik, Cors van, E-mail: c.vanschaik@vumc.nl [Department of Radiology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Hofman, Mark B.M., E-mail: mbm.hofman@vumc.nl [Department of Physics and Medical Technology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Leeuwen, Paul A.M. van, E-mail: pam.vleeuwen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands)

    2012-09-15

    Background: Quantification of abdominal blood flow is essential for a variety of gastrointestinal and hepatic topics such as liver transplantation or metabolic flux measurement, but those need to be performed during surgery. It is not clear whether Duplex Doppler Ultrasound during surgery or MRI before surgery is the tool to choose. Objective: To examine whether preoperative evaluation of abdominal blood flow using MRI could prove to be a useful and reliable alternative for the perioperative sonographic approach. Methods: In this study portal and renal venous flow and hepatic arterial flow were sequentially quantified by preoperative MRI, preoperative and perioperative Duplex Doppler Ultrasound (DDUS). 55 Patients scheduled for major abdominal surgery were studied and methods and settings were compared. Additionally, average patient population values were compared. Results: Mean (±SD) plasmaflow measured by perioperative DDUS, preoperative DDUS and MRI, respectively was 433 ± 200/423 ± 162/507 ± 96 ml/min (portal vein); 96 ± 70/74 ± 41/108 ± 91 ml/min (hepatic artery); 248 ± 139/201 ± 118/219 ± 69 ml/min (renal vein). No differences between the different settings of DDUS measurement were detected. Equality of mean was observed for all measurements. Bland Altman Plots showed widespread margins. Hepatic arterial flow measurements correlated with each other, but portal and renal venous flow correlations were absent. Conclusions: Surgery and method (DDUS vs. MRI) do not affect mean flow values. Individual comparison is restricted due to wide range in measurements. Since MRI proves to be more reliable with respect to inter-observer variability, we recommend using mean MRI results in experimental setups.

  8. Hemodynamic alterations measured with phase-contrast MRI in a giant cerebral aneurysm treated with a flow-diverting stent

    Directory of Open Access Journals (Sweden)

    Matthew Ethan MacDonald, PhD

    2015-01-01

    Full Text Available Many risk factors have been proposed in the development of the cerebral aneurysms. Hemodynamics including blood velocity, volume flow rate (VFR, and intravascular pressure are thought to be prognostic indicators of aneurysm development. We hypothesize that treatment of cerebral aneurysm using a flow-diverting stent will bring these hemodynamic parameters closer to those observed on the contralateral side. In the current study, a patient with a giant cerebral aneurysm was studied pre- and postoperatively using phase contrast MRI (PC-MRI to measure the hemodynamic changes resulting from the deployment of a flow-diverting stent. PC-MRI was used to calculate intravascular pressure, which was compared to more invasive endovascular catheter-derived measurements. After stent placement, the measured VFRs in vessels of the treated hemisphere approached those measured on the contralateral side, and flow symmetry changed from a laterality index of -0.153 to 0.116 in the middle cerebral artery. Pressure estimates derived from the PC-MRI velocity data had an average difference of 6.1% as compared to invasive catheter transducer measurements. PC-MRI can measure the hemodynamic parameters with the same accuracy as invasive methods pre- and postoperatively.

  9. Validation of Continuously Tagged MRI for the Measurement of Dynamic 3D Skeletal Muscle Tissue Deformation

    CERN Document Server

    Moerman, Kevin M; Simms, Ciaran K; Lamerichs, Rolf M; Stoker, Jaap; Nederveen, Aart J

    2016-01-01

    A SPAMM tagged MRI methodology is presented allowing continuous (3.3-3.6 Hz) sampling of 3D dynamic soft tissue deformation using non-segmented 3D acquisitions. The 3D deformation is reconstructed by the combination of 3 mutually orthogonal tagging directions, thus requiring only 3 repeated motion cycles. In addition a fully automatic post-processing framework is presented employing Gabor scale-space and filter-bank analysis for tag extrema segmentation and triangulated surface fitting aided by Gabor filter bank derived surface normals. Deformation is derived following tracking of tag surface triplet triangle intersections. The dynamic deformation measurements were validated using indentation tests (~20 mm deep at 12 mm/s) on a silicone gel soft tissue phantom containing contrasting markers which provide a reference measure of deformation. In addition, the techniques were evaluated in-vivo for dynamic skeletal muscle tissue deformation measurement during indentation of the biceps region of the upper arm in a ...

  10. MRI-compatible noninvasive continuous blood pressure measurement using fiber optics

    Science.gov (United States)

    Harja, Juha; Myllylä, Teemu S.; Sorvoja, Hannu S. S.; Myllylä, Risto A.; Elseoud, Ahmed A.; Nikkinen, Juha; Kiviniemi, Vesa; Tervonen, Osmo

    2010-02-01

    This report focuses on designing and implementing a non-invasive blood pressure measuring device capable of being used during magnetic resonance imaging. This device is based on measuring pulse wave velocity in arterial blood and using the obtained result to estimate diastolic blood pressure. Pulse transit times are measured by two fibre optical accelerometers placed over chest and carotid artery. The fabricated accelerometer contains two static fibres and a cantilever beam. The free end of the beam is angled at 90 degrees to act as a reflecting surface. Optical fibres are used for both illuminating the surface and receiving the reflected light. Acceleration applied to the sensor causes deflection of the beam, whereupon the amount of reflected light changes. The sensor output voltage is proportional to the intensity of the reflected light. Tests conducted on the electronics and sensors inside an MRI room during scanning proved that the device is MR conditional. No artifacts or distortions were detected.

  11. 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

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

    International Nuclear Information System (INIS)

    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

  13. Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

    International Nuclear Information System (INIS)

    Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (vp) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. vp and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between vp and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

  14. Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Moran [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Liberman, Gilad; Vitinshtein, Faina; Aizenstein, Orna [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Nadav, Guy [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Faculty of Engineering, Tel Aviv (Israel); Blumenthal, Deborah T.; Bokstein, Felix [Tel Aviv Sourasky Medical Center, Neuro-Oncology Service, Tel Aviv (Israel); Bashat, Dafna Ben [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv (Israel)

    2015-07-15

    Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

  15. Measurement, time-stamping, and analysis of electrodermal activity in fMRI

    Science.gov (United States)

    Smyser, Christopher; Grabowski, Thomas J.; Rainville, Pierre; Bechara, Antione; Razavi, Mehrdad; Mehta, Sonya; Eaton, Brent L.; Bolinger, Lizann

    2002-04-01

    A low cost fMRI-compatible system was developed for detecting electrodermal activity without inducing image artifact. Subject electrodermal activity was measured on the plantar surface of the foot using a standard recording circuit. Filtered analog skin conductance responses (SCR) were recorded with a general purpose, time-stamping data acquisition system. A conditioning paradigm involving painful thermal stimulation was used to demonstrate SCR detection and investigate neural correlates of conditioned autonomic activity. 128x128 pixel EPI-BOLD images were acquired with a GE 1.5T Signa scanner. Image analysis was performed using voxel-wise multiple linear regression. The covariate of interest was generated by convolving stimulus event onset with a standard hemodynamic response function. The function was time-shifted to determine optimal activation. Significance was tested using the t-statistic. Image quality was unaffected by the device, and conditioned and unconditioned SCRs were successfully detected. Conditioned SCRs correlated significantly with activity in the right anterior insular cortex. The effect was more robust when responses were scaled by SCR amplitude. The ability to measure and time register SCRs during fMRI acquisition enables studies of cognitive processes marked by autonomic activity, including those involving decision-making, pain, emotion, and addiction.

  16. SU-E-J-120: Comparing 4D CT Computed Ventilation to Lung Function Measured with Hyperpolarized Xenon-129 MRI

    Energy Technology Data Exchange (ETDEWEB)

    Neal, B; Chen, Q [University of Virginia, Charlottesville, VA (United States)

    2015-06-15

    Purpose: To correlate ventilation parameters computed from 4D CT to ventilation, profusion, and gas exchange measured with hyperpolarized Xenon-129 MRI for a set of lung cancer patients. Methods: Hyperpolarized Xe-129 MRI lung scans were acquired for lung cancer patients, before and after radiation therapy, measuring ventilation, perfusion, and gas exchange. In the standard clinical workflow, these patients also received 4D CT scans before treatment. Ventilation was computed from 4D CT using deformable image registration (DIR). All phases of the 4D CT scan were registered using a B-spline deformable registration. Ventilation at the voxel level was then computed for each phase based on a Jacobian volume expansion metric, yielding phase sorted ventilation images. Ventilation based upon 4D CT and Xe-129 MRI were co-registered, allowing qualitative visual comparison and qualitative comparison via the Pearson correlation coefficient. Results: Analysis shows a weak correlation between hyperpolarized Xe-129 MRI and 4D CT DIR ventilation, with a Pearson correlation coefficient of 0.17 to 0.22. Further work will refine the DIR parameters to optimize the correlation. The weak correlation could be due to the limitations of 4D CT, registration algorithms, or the Xe-129 MRI imaging. Continued development will refine parameters to optimize correlation. Conclusion: Current analysis yields a minimal correlation between 4D CT DIR and Xe-129 MRI ventilation. Funding provided by the 2014 George Amorino Pilot Grant in Radiation Oncology at the University of Virginia.

  17. SU-E-J-120: Comparing 4D CT Computed Ventilation to Lung Function Measured with Hyperpolarized Xenon-129 MRI

    International Nuclear Information System (INIS)

    Purpose: To correlate ventilation parameters computed from 4D CT to ventilation, profusion, and gas exchange measured with hyperpolarized Xenon-129 MRI for a set of lung cancer patients. Methods: Hyperpolarized Xe-129 MRI lung scans were acquired for lung cancer patients, before and after radiation therapy, measuring ventilation, perfusion, and gas exchange. In the standard clinical workflow, these patients also received 4D CT scans before treatment. Ventilation was computed from 4D CT using deformable image registration (DIR). All phases of the 4D CT scan were registered using a B-spline deformable registration. Ventilation at the voxel level was then computed for each phase based on a Jacobian volume expansion metric, yielding phase sorted ventilation images. Ventilation based upon 4D CT and Xe-129 MRI were co-registered, allowing qualitative visual comparison and qualitative comparison via the Pearson correlation coefficient. Results: Analysis shows a weak correlation between hyperpolarized Xe-129 MRI and 4D CT DIR ventilation, with a Pearson correlation coefficient of 0.17 to 0.22. Further work will refine the DIR parameters to optimize the correlation. The weak correlation could be due to the limitations of 4D CT, registration algorithms, or the Xe-129 MRI imaging. Continued development will refine parameters to optimize correlation. Conclusion: Current analysis yields a minimal correlation between 4D CT DIR and Xe-129 MRI ventilation. Funding provided by the 2014 George Amorino Pilot Grant in Radiation Oncology at the University of Virginia

  18. Automated pulmonary lobar ventilation measurements using volume-matched thoracic CT and MRI

    Science.gov (United States)

    Guo, F.; Svenningsen, S.; Bluemke, E.; Rajchl, M.; Yuan, J.; Fenster, A.; Parraga, G.

    2015-03-01

    Objectives: To develop and evaluate an automated registration and segmentation pipeline for regional lobar pulmonary structure-function measurements, using volume-matched thoracic CT and MRI in order to guide therapy. Methods: Ten subjects underwent pulmonary function tests and volume-matched 1H and 3He MRI and thoracic CT during a single 2-hr visit. CT was registered to 1H MRI using an affine method that incorporated block-matching and this was followed by a deformable step using free-form deformation. The resultant deformation field was used to deform the associated CT lobe mask that was generated using commercial software. 3He-1H image registration used the same two-step registration method and 3He ventilation was segmented using hierarchical k-means clustering. Whole lung and lobar 3He ventilation and ventilation defect percent (VDP) were generated by mapping ventilation defects to CT-defined whole lung and lobe volumes. Target CT-3He registration accuracy was evaluated using region- , surface distance- and volume-based metrics. Automated whole lung and lobar VDP was compared with semi-automated and manual results using paired t-tests. Results: The proposed pipeline yielded regional spatial agreement of 88.0+/-0.9% and surface distance error of 3.9+/-0.5 mm. Automated and manual whole lung and lobar ventilation and VDP were not significantly different and they were significantly correlated (r = 0.77, p pulmonary structural-functional maps with high accuracy and robustness, providing an important tool for image-guided pulmonary interventions.

  19. An optical setup for electric field measurements in MRI with high spatial resolution.

    Science.gov (United States)

    Reiss, Simon; Bitzer, Andreas; Bock, Michael

    2015-06-01

    Electric field measurements in the magnetic resonance (MR) imaging environment are important to assess potentially dangerous radio-frequency (RF) heating in the vicinity of metallic structures such as coils, implants or catheters. So far, E-field measurements have been performed with dipole antennas that lag of limited spatial resolution and which are difficult to use in the magnet bore as they interfere with the RF transmit field of the MRI system. In this work an electro-optic sensor is presented that utilizes the Pockels effect to measure the E-field in a clinical MR system with high spatial resolution. This sensor consists of dielectric materials only and thus, it only minimally influences the measured E-field distribution. A 10 m long flexible optical fiber connects the small sensor head to a remote processing unit where the optical signal is transformed into an electrical output signal. Spatially resolved qualitative E-field measurements were performed in a 1.5 T clinical MR system in the vicinity of metallic samples and an active tracking catheter with a resolution of up to 1 mm. The near-field pattern of a resonant U-shaped metallic sample was clearly identified and compared with numerical simulations. A more complex field behavior was found for the tracking catheter where strong E-field enhancements were observed at the distal tip and at its proximal part outside the phantom solution. Due to its sub-mm spatial resolution the optical sensor approach provides detailed insight into the complex and difficult to access field distributions close to implants and metallic structures and has turned out to be promising tool for MRI field and safety inspections. PMID:25984961

  20. An optical setup for electric field measurements in MRI with high spatial resolution

    International Nuclear Information System (INIS)

    Electric field measurements in the magnetic resonance (MR) imaging environment are important to assess potentially dangerous radio-frequency (RF) heating in the vicinity of metallic structures such as coils, implants or catheters. So far, E-field measurements have been performed with dipole antennas that lag of limited spatial resolution and which are difficult to use in the magnet bore as they interfere with the RF transmit field of the MRI system. In this work an electro-optic sensor is presented that utilizes the Pockels effect to measure the E-field in a clinical MR system with high spatial resolution. This sensor consists of dielectric materials only and thus, it only minimally influences the measured E-field distribution. A 10 m long flexible optical fiber connects the small sensor head to a remote processing unit where the optical signal is transformed into an electrical output signal. Spatially resolved qualitative E-field measurements were performed in a 1.5 T clinical MR system in the vicinity of metallic samples and an active tracking catheter with a resolution of up to 1 mm. The near-field pattern of a resonant U-shaped metallic sample was clearly identified and compared with numerical simulations. A more complex field behavior was found for the tracking catheter where strong E-field enhancements were observed at the distal tip and at its proximal part outside the phantom solution. Due to its sub-mm spatial resolution the optical sensor approach provides detailed insight into the complex and difficult to access field distributions close to implants and metallic structures and has turned out to be promising tool for MRI field and safety inspections. (paper)

  1. Measuring brain hemodynamic changes in a songbird: responses to hypercapnia measured with functional MRI and near-infrared spectroscopy

    Science.gov (United States)

    Vignal, C.; Boumans, T.; Montcel, B.; Ramstein, S.; Verhoye, M.; Van Audekerke, J.; Mathevon, N.; Van der Linden, A.; Mottin, S.

    2008-05-01

    Songbirds have been evolved into models of choice for the study of the cerebral underpinnings of vocal communication. Nevertheless, there is still a need for in vivo methods allowing the real-time monitoring of brain activity. Functional Magnetic Resonance Imaging (fMRI) has been applied in anesthetized intact songbirds. It relies on blood oxygen level-dependent (BOLD) contrast revealing hemodynamic changes. Non-invasive near-infrared spectroscopy (NIRS) is based on the weak absorption of near-infrared light by biological tissues. Time-resolved femtosecond white laser NIRS is a new probing method using real-time spectral measurements which give access to the local variation of absorbing chromophores such as hemoglobins. In this study, we test the efficiency of our time-resolved NIRS device in monitoring physiological hemodynamic brain responses in a songbird, the zebra finch (Taeniopygia guttata), using a hypercapnia event (7% inhaled CO2). The results are compared to those obtained using BOLD fMRI. The NIRS measurements clearly demonstrate that during hypercapnia the blood oxygen saturation level increases (increase in local concentration of oxyhemoglobin, decrease in deoxyhemoglobin concentration and total hemoglobin concentration). Our results provide the first correlation in songbirds of the variations in total hemoglobin and oxygen saturation level obtained from NIRS with local BOLD signal variations.

  2. Measuring brain hemodynamic changes in a songbird: responses to hypercapnia measured with functional MRI and near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Songbirds have been evolved into models of choice for the study of the cerebral underpinnings of vocal communication. Nevertheless, there is still a need for in vivo methods allowing the real-time monitoring of brain activity. Functional Magnetic Resonance Imaging (fMRI) has been applied in anesthetized intact songbirds. It relies on blood oxygen level-dependent (BOLD) contrast revealing hemodynamic changes. Non-invasive near-infrared spectroscopy (NIRS) is based on the weak absorption of near-infrared light by biological tissues. Time-resolved femtosecond white laser NIRS is a new probing method using real-time spectral measurements which give access to the local variation of absorbing chromophores such as hemoglobins. In this study, we test the efficiency of our time-resolved NIRS device in monitoring physiological hemodynamic brain responses in a songbird, the zebra finch (Taeniopygia guttata), using a hypercapnia event (7% inhaled CO2). The results are compared to those obtained using BOLD fMRI. The NIRS measurements clearly demonstrate that during hypercapnia the blood oxygen saturation level increases (increase in local concentration of oxyhemoglobin, decrease in deoxyhemoglobin concentration and total hemoglobin concentration). Our results provide the first correlation in songbirds of the variations in total hemoglobin and oxygen saturation level obtained from NIRS with local BOLD signal variations

  3. Measuring brain hemodynamic changes in a songbird: responses to hypercapnia measured with functional MRI and near-infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vignal, C; Mathevon, N [ENES EA 3988, Universite Jean Monnet, Saint-Etienne (France); Boumans, T; Verhoye, M; Audekerke, J van; Linden, A van der [Bio-Imaging Laboratory, University of Antwerp, Antwerp (Belgium); Montcel, B; Ramstein, S; Mottin, S [Hubert Curien CNRS UMR 5516, Universite Jean Monnet, Saint-Etienne (France)], E-mail: Clementine.Vignal@univ-st-etienne.fr

    2008-05-21

    Songbirds have been evolved into models of choice for the study of the cerebral underpinnings of vocal communication. Nevertheless, there is still a need for in vivo methods allowing the real-time monitoring of brain activity. Functional Magnetic Resonance Imaging (fMRI) has been applied in anesthetized intact songbirds. It relies on blood oxygen level-dependent (BOLD) contrast revealing hemodynamic changes. Non-invasive near-infrared spectroscopy (NIRS) is based on the weak absorption of near-infrared light by biological tissues. Time-resolved femtosecond white laser NIRS is a new probing method using real-time spectral measurements which give access to the local variation of absorbing chromophores such as hemoglobins. In this study, we test the efficiency of our time-resolved NIRS device in monitoring physiological hemodynamic brain responses in a songbird, the zebra finch (Taeniopygia guttata), using a hypercapnia event (7% inhaled CO{sub 2}). The results are compared to those obtained using BOLD fMRI. The NIRS measurements clearly demonstrate that during hypercapnia the blood oxygen saturation level increases (increase in local concentration of oxyhemoglobin, decrease in deoxyhemoglobin concentration and total hemoglobin concentration). Our results provide the first correlation in songbirds of the variations in total hemoglobin and oxygen saturation level obtained from NIRS with local BOLD signal variations.

  4. Values of kinetic features measured by computer-aided for breast MRI

    International Nuclear Information System (INIS)

    Objective: To investigate the value of kinetic features measured by computer-aided diagnosis (CAD) for breast MRI. Methods: One hundred and sixty four lesions diagnosed pathologically by operation or biopsy comprised the analysis set. Automated lesion kinetic information from CADStream programs for breast MRI was identified. Three CAD variables were compared for benign and malignant lesions: initial phase peak enhancement (greatest percentage of signal intensity increase on first contrast enhanced sequence), delayed phase enhancement categorized by a single type of kinetics comprising the largest percentage of enhancement (washout, plateau, or persistent), and delayed phase enhancement categorized by single most suspicious type of kinetics (any washout > any plateau > any persistent). Morphological characteristics of breast lesions were described according to breast imaging and reporting data system (BI-RADS). Initial phase peak enhancement mean values between benign and malignant breast lesions were compared by using Wilcoxon rank-sum test, delayed phase enhancement categorized by a single type of kinetics comprising the largest percentage of enhancement or by single most suspicious type of kinetics between benign and malignant breast lesions were compared by using Chi-square test. Results: There were 72 benign and 92 malignant breast lesions. A total of 123 (75.0%) mass lesions were identified,and the other 41 (25.0%) lesions showed no mass. Thirty lesions were BI-RADS-MRI 2, 68 lesions were BI-RADS-MRI 3, 43 lesions were BI-RADS-MRI 4, 23 lesions were BI-RADS-MRI 5. Initial phase peak enhancement mean values of benign and malignant lesions were 237% (69% to 629%) and 336% (86% to 793%), respectively. There was no significant difference between benign and malignant lesions in initial peak enhancement mean value (Z=-1.626, P=0.104). Delayed phase enhancement categorized by single most suspicious type of kinetics (any washout > any plateau > any persistent) for

  5. Classification of normal and pathological aging processes based on brain MRI morphology measures

    Science.gov (United States)

    Perez-Gonzalez, J. L.; Yanez-Suarez, O.; Medina-Bañuelos, V.

    2014-03-01

    Reported studies describing normal and abnormal aging based on anatomical MRI analysis do not consider morphological brain changes, but only volumetric measures to distinguish among these processes. This work presents a classification scheme, based both on size and shape features extracted from brain volumes, to determine different aging stages: healthy control (HC) adults, mild cognitive impairment (MCI), and Alzheimer's disease (AD). Three support vector machines were optimized and validated for the pair-wise separation of these three classes, using selected features from a set of 3D discrete compactness measures and normalized volumes of several global and local anatomical structures. Our analysis show classification rates of up to 98.3% between HC and AD; of 85% between HC and MCI and of 93.3% for MCI and AD separation. These results outperform those reported in the literature and demonstrate the viability of the proposed morphological indexes to classify different aging stages.

  6. Correlation of auditory brain stem response and the MRI measurements in neuro-degenerative disorders

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, Hidekazu (Tokyo Women' s Medical Coll. (Japan))

    1989-06-01

    The purpose of this study is to elucidate correlations of several MRI measurements of the cranium and brain, functioning as a volume conductor, to the auditory brain stem response (ABR) in neuro-degenerative disorders. The subjects included forty-seven patients with spinocerebellar degeneration (SCD) and sixteen of amyotrophic lateral sclerosis (ALS). Statistically significant positive correlations were found between I-V and III-V interpeak latencies (IPLs) and the area of cranium and brain in the longitudinal section of SCD patients, and between I-III and III-V IPLs and the area in the longitudinal section of those with ALS. And, also there were statistically significant correlations between the amplitude of the V wave and the area of brain stem as well as that of the cranium in the longitudinal section of SCD patients, and between the amplitude of the V wave and the area of the cerebrum in the longitudinal section of ALS. In conclusion, in the ABR, the IPLs were prolonged and the amplitude of the V wave was decreased while the MRI size of the cranium and brain increased. When the ABR is applied to neuro-degenerative disorders, it might be important to consider not only the conduction of the auditory tracts in the brain stem, but also the correlations of the size of the cranium and brain which act as a volume conductor. (author).

  7. Noninvasive measurement of liver iron concentration at MRI in children with acute leukemia: initial results

    Energy Technology Data Exchange (ETDEWEB)

    Vag, Tibor; Krumbein, Ines; Reichenbach, Juergen R.; Lopatta, Eric; Stenzel, Martin; Kaiser, Werner A.; Mentzel, Hans-Joachim [Friedrich Schiller University Jena, Institute of Diagnostic and Interventional Radiology, Jena (Germany); Kentouche, Karim; Beck, James [Friedrich Schiller University Jena, Department of Pediatrics, Jena (Germany); Renz, Diane M. [Charite University Medicine Berlin, Department of Radiology, Campus Virchow Clinic, Berlin (Germany)

    2011-08-15

    Routine assessment of body iron load in patients with acute leukemia is usually done by serum ferritin (SF) assay; however, its sensitivity is impaired by different conditions including inflammation and malignancy. To estimate, using MRI, the extent of liver iron overload in children with acute leukemia and receiving blood transfusions, and to examine the association between the degree of hepatic iron overload and clinical parameters including SF and the transfusion iron load (TIL). A total of 25 MRI measurements of the liver were performed in 15 children with acute leukemia (mean age 9.75 years) using gradient-echo sequences. Signal intensity ratios between the liver and the vertebral muscle (L/M ratio) were calculated and compared with SF-levels. TIL was estimated from the cumulative blood volume received, assuming an amount of 200 mg iron per transfused red blood cell unit. Statistical analysis revealed good correlation between the L/M SI ratio and TIL (r = -0.67, P = 0.002, 95% confidence interval CI = -0.83 to -0.34) in patients with acute leukemia as well as between L/M SI ratio and SF (r = -0.76, P = 0.0003, 95% CI = -0.89 to -0.52). SF may reliably reflect liver iron stores as a routine marker in patients suffering from acute leukemia. (orig.)

  8. Correlation of auditory brain stem response and the MRI measurements in neuro-degenerative disorders

    International Nuclear Information System (INIS)

    The purpose of this study is to elucidate correlations of several MRI measurements of the cranium and brain, functioning as a volume conductor, to the auditory brain stem response (ABR) in neuro-degenerative disorders. The subjects included forty-seven patients with spinocerebellar degeneration (SCD) and sixteen of amyotrophic lateral sclerosis (ALS). Statistically significant positive correlations were found between I-V and III-V interpeak latencies (IPLs) and the area of cranium and brain in the longitudinal section of SCD patients, and between I-III and III-V IPLs and the area in the longitudinal section of those with ALS. And, also there were statistically significant correlations between the amplitude of the V wave and the area of brain stem as well as that of the cranium in the longitudinal section of SCD patients, and between the amplitude of the V wave and the area of the cerebrum in the longitudinal section of ALS. In conclusion, in the ABR, the IPLs were prolonged and the amplitude of the V wave was decreased while the MRI size of the cranium and brain increased. When the ABR is applied to neuro-degenerative disorders, it might be important to consider not only the conduction of the auditory tracts in the brain stem, but also the correlations of the size of the cranium and brain which act as a volume conductor. (author)

  9. A novel high temporal resolution phase contrast MRI technique for measuring mitral valve flows

    Science.gov (United States)

    Voorhees, Abram; Bohmann, Katja; McGorty, Kelly Anne; Wei, Timothy; Chen, Qun

    2005-11-01

    Mitral valve flow imaging is inherently difficult due to valve plane motion and high blood flow velocities, which can range from 200 cm/s to 700 cm/s under regurgitant conditions. As such, insufficient temporal resolution has hampered imaging of mitral valve flows using magnetic resonance imaging (MRI). A novel phase contrast MRI technique, phase contrast using phase train imaging (PCPTI), has been developed to address the high temporal resolution needs for imaging mitral valve flows. The PCPTI sequence provides the highest temporal resolution to-date (6 ms) for measuring in-plane and through-plane flow patterns, with each velocity component acquired in a separate breathhold. Tested on healthy human volunteers, comparison to a conventional retrogated PC-FLASH cine sequence showed reasonable agreement. Results from a more rigorous validation using digital particle image velocimetry technique will be presented. The technique will be demonstrated in vitro using a physiological flow phantom and a St. Jude Medical Masters Series prosthetic valve.

  10. A preliminary study of the thermal measurement with nMAG gel dosimeter by MRI

    International Nuclear Information System (INIS)

    The methacrylic acid (nMAG) gel dosimeter is an effective tool for 3-dimensional quality assurance of radiation therapy. In addition to radiation induced polymerization effects, the nMAG gel also responds to temperature variation. In this study, we proposed a new method to evaluate the thermal response in thermal therapy using nMAG gel and magnetic resonance image (MRI) scans. Several properties of nMAG have been investigated including the R2 relaxation rate, temperature sensitivity, and temperature linearity of the thermal dose response. nMAG was heated by the double-boiling method in the range of 37–45 °C. MRI scans were performed with the head coil receiver. The temperature to R2 response curve was analyzed and simple linear regression was performed with an R-square value of 0.9835. The measured data showed a well inverse linear relationship between R2 and temperature. We conclude that the nMAG polymer gel dosimeter shows great potential as a technique to evaluate the temperature rise during thermal surgery. - Highlights: • Using gel dosimeter the thermal response is evaluated. • The nMAG gel has a linear response between 37 °C and 45 °C. • Using gel dosimeter the thermal damage of normal tissue during thermal surgery may be evaluated

  11. Tracer kinetic modelling of tumour angiogenesis based on dynamic contrast-enhanced CT and MRI measurements

    International Nuclear Information System (INIS)

    Technical developments in both magnetic resonance imaging (MRI) and computed tomography (CT) have helped to reduce scan times and expedited the development of dynamic contrast-enhanced (DCE) imaging techniques. Since the temporal change of the image signal following the administration of a diffusible, extracellular contrast agent (CA) is related to the local blood supply and the extravasation of the CA into the interstitial space, DCE imaging can be used to assess tissue microvasculature and microcirculation. It is the aim of this review to summarize the biophysical and tracer kinetic principles underlying this emerging imaging technique offering great potential for non-invasive characterization of tumour angiogenesis. In the first part, the relevant contrast mechanisms are presented that form the basis to relate signal variations measured by serial CT and MRI to local tissue concentrations of the administered CA. In the second part, the concepts most widely used for tracer kinetic modelling of concentration-time courses derived from measured DCE image data sets are described in a consistent and unified manner to highlight their particular structure and assumptions as well as the relationships among them. Finally, the concepts presented are exemplified by the analysis of representative DCE data as well as discussed with respect to present and future applications in cancer diagnosis and therapy. Depending on the specific protocol used for the acquisition of DCE image data and the particular model applied for tracer kinetic analysis of the derived concentration-time courses, different aspects of tumour angiogenesis can be quantified in terms of well-defined physiological tissue parameters. DCE imaging offers promising prospects for improved tumour diagnosis, individualization of cancer treatment as well as the evaluation of novel therapeutic concepts in preclinical and early-stage clinical trials. (orig.)

  12. Comparison of ASL and DCE MRI for the non-invasive measurement of renal blood flow: quantification and reproducibility

    International Nuclear Information System (INIS)

    To investigate the reproducibility of arterial spin labelling (ASL) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and quantitatively compare these techniques for the measurement of renal blood flow (RBF). Sixteen healthy volunteers were examined on two different occasions. ASL was performed using a multi-TI FAIR labelling scheme with a segmented 3D-GRASE imaging module. DCE MRI was performed using a 3D-FLASH pulse sequence. A Bland-Altman analysis was used to assess repeatability of each technique, and determine the degree of correspondence between the two methods. The overall mean cortical renal blood flow (RBF) of the ASL group was 263 ± 41 ml min-1 [100 ml tissue]-1, and using DCE MRI was 287 ± 70 ml min-1 [100 ml tissue]-1. The group coefficient of variation (CVg) was 18 % for ASL and 28 % for DCE-MRI. Repeatability studies showed that ASL was more reproducible than DCE with CVgs of 16 % and 25 % for ASL and DCE respectively. Bland-Altman analysis comparing the two techniques showed a good agreement. The repeated measures analysis shows that the ASL technique has better reproducibility than DCE-MRI. Difference analysis shows no significant difference between the RBF values of the two techniques. (orig.)

  13. Comparison of ASL and DCE MRI for the non-invasive measurement of renal blood flow: quantification and reproducibility

    Energy Technology Data Exchange (ETDEWEB)

    Cutajar, Marica; Hales, Patrick W.; Clark, Christopher A.; Gordon, Isky [UCL Institute of Child Health, Imaging and Biophysics Unit, London (United Kingdom); Thomas, David L. [UCL Institute of Neurology, Department of Brain Repair and Rehabilitation, London (United Kingdom); Banks, T. [Great Ormond Street Hospital, Department of Radiology, London (United Kingdom)

    2014-06-15

    To investigate the reproducibility of arterial spin labelling (ASL) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and quantitatively compare these techniques for the measurement of renal blood flow (RBF). Sixteen healthy volunteers were examined on two different occasions. ASL was performed using a multi-TI FAIR labelling scheme with a segmented 3D-GRASE imaging module. DCE MRI was performed using a 3D-FLASH pulse sequence. A Bland-Altman analysis was used to assess repeatability of each technique, and determine the degree of correspondence between the two methods. The overall mean cortical renal blood flow (RBF) of the ASL group was 263 ± 41 ml min{sup -1} [100 ml tissue]{sup -1}, and using DCE MRI was 287 ± 70 ml min{sup -1} [100 ml tissue]{sup -1}. The group coefficient of variation (CV{sub g}) was 18 % for ASL and 28 % for DCE-MRI. Repeatability studies showed that ASL was more reproducible than DCE with CV{sub g}s of 16 % and 25 % for ASL and DCE respectively. Bland-Altman analysis comparing the two techniques showed a good agreement. The repeated measures analysis shows that the ASL technique has better reproducibility than DCE-MRI. Difference analysis shows no significant difference between the RBF values of the two techniques. (orig.)

  14. Skin sodium measured with (23) Na MRI at 7.0 T

    OpenAIRE

    Linz, P.; Santoro, D.; Renz, W.; J. Rieger; Ruehle, A.; Ruff, J; Deimling, M.; Rakova, N.; Muller, D.N.; Luft, F. C.; Titze, J.; Niendorf, T

    2015-01-01

    Skin sodium (Na+ ) storage, as a physiologically important regulatory mechanism for blood pressure, volume regulation and, indeed, survival, has recently been rediscovered. This has prompted the development of MRI methods to assess Na+ storage in humans (23 Na MRI) at 3.0 T. This work examines the feasibility of high in-plane spatial resolution 23 Na MRI in skin at 7.0 T. A two-channel transceiver radiofrequency (RF) coil array tailored for skin MRI at 7.0 T (f = 78.5 MHz) is proposed. Specif...

  15. Measurement of femoral torsion and tibial torsion using magnetic resonance imaging (MRI); Kernspintomographisches Messungsverfahren von Femurantetorsion und Tibiatorsion

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, B. [Abt. Radiologische Diagnostik, Univ. Freiburg im Breisgau (Germany); Laubenberger, J. [Abt. Radiologische Diagnostik, Univ. Freiburg im Breisgau (Germany); Wildner, M. [Abt. Orthopaedie, Univ. Freiburg im Breisgau (Germany); Exne, V. [Abt. Orthopaedie, Univ. Freiburg im Breisgau (Germany); Langer, M. [Abt. Radiologische Diagnostik, Univ. Freiburg im Breisgau (Germany)

    1995-03-01

    A new MRI method for the measurement of femoral torsion and tibial torsion is presented. Axial images were generated using a standard gradient echo sequence (FLASH 2D). Otherwise measurement of femoral and tibial torsion was performed according to an established CT method. The torsion angles measured using MRI were in accordance with the angles measured using the CT method. The MRI method was not more time-consuming than the CT method. In respect of radiation exposure, MRI determination of femoral and tibial torsion should be considered particularly in children and patients who have to undergo repeated torsion measurements. (orig.) [Deutsch] Es wird ein kernspintomographisches Verfahren zur Bestimmung von Femurtorsion und Tibiatorsion vorgestellt. Die Schnittbilder wurden mittels einer Standard-Gradienten-Echo-Sequenz (FLASH 2D) erzeugt. Hinsichtlich der Methodik der Achsenmessung wurde in exakt CT-analoger Weise verfahren. Die kernspintomographisch ermittelten Torsionswerte weisen eine gute Uebereinstimmung mit den Ergebnissen der computertomographischen Referenzmethode auf. Der Zeitaufwand der kernspintomographischen Torsionsbestimmung entspricht dem des computertomographischen Verfahrens. Im Hinblick auf die Strahlenbelastung ist die kernspintomographische Bestimmung von Femurtorsion und Tibiatorsion daher vor allem bei jungen Patienten von Vorteil gegenueber den computertomographischen Verfahren. (orig.)

  16. Effect of magnetic field fluctuation on ultra-low field MRI measurements in the unshielded laboratory environment

    Science.gov (United States)

    Liu, Chao; Chang, Baolin; Qiu, Longqing; Dong, Hui; Qiu, Yang; Zhang, Yi; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming

    2015-08-01

    Magnetic field fluctuations in our unshielded urban laboratory can reach hundreds of nT in the noisy daytime and is only a few nT in the quiet midnight. The field fluctuation causes the Larmor frequency fL to drift randomly for several Hz during the unshielded ultra-low field (ULF) nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) measurements, thus seriously spoiling the averaging effect and causing imaging artifacts. By using an active compensation (AC) technique based on the spatial correlation of the low-frequency magnetic field fluctuation, the field fluctuation can be suppressed to tens of nT, which is a moderate situation between the noisy daytime and the quiet midnight. In this paper, the effect of the field fluctuation on ULF MRI measurements was investigated. The 1D and 2D MRI signals of a water phantom were measured using a second-order low-Tc superconducting quantum interference device (SQUID) in three fluctuation cases: severe fluctuation (noisy daytime), moderate fluctuation (daytime with AC) and minute fluctuation (quiet midnight) when different gradient fields were applied. When the active compensation is applied or when the frequency encoding gradient field Gx reaches a sufficiently strong value in our measurements, the image artifacts become invisible in all three fluctuation cases. Therefore it is feasible to perform ULF-MRI measurements in unshielded urban environment without imaging artifacts originating from magnetic fluctuations by using the active compensation technique and/or strong gradient fields.

  17. Temperature elevation by HIFU in ex vivo porcine muscle: MRI measurement and simulation study

    Energy Technology Data Exchange (ETDEWEB)

    Solovchuk, Maxim A., E-mail: solovchuk@gmail.com [Center for Advanced Study in Theoretical Sciences (CASTS), National Taiwan University, Taipei 10617, Taiwan (China); Hwang, San Chao; Chang, Hsu [Medical Engineering Research Division, National Health Research Institute, Miaoli 35053, Taiwan (China); Thiriet, Marc [Sorbonne Universités, UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions, F-75005, Paris (France); Sheu, Tony W. H., E-mail: twhsheu@ntu.edu.tw [Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan, Republic of China and Center for Advanced Study in Theoretical Sciences (CASTS), National Taiwan University, Taipei 10617, Taiwan (China)

    2014-05-15

    Purpose: High-intensity focused ultrasound is a rapidly developing medical technology with a large number of potential clinical applications. Computational model can play a pivotal role in the planning and optimization of the treatment based on the patient's image. Nonlinear propagation effects can significantly affect the temperature elevation and should be taken into account. In order to investigate the importance of nonlinear propagation effects, nonlinear Westervelt equation was solved. Weak nonlinear propagation effects were studied. The purpose of this study was to investigate the correlation between the predicted and measured temperature elevations and lesion in a porcine muscle. Methods: The investigated single-element transducer has a focal length of 12 cm, an aperture of 8 cm, and frequency of 1.08 MHz. Porcine muscle was heated for 30 s by focused ultrasound transducer with an acoustic power in the range of 24–56 W. The theoretical model consists of nonlinear Westervelt equation with relaxation effects being taken into account and Pennes bioheat equation. Results: Excellent agreement between the measured and simulated temperature rises was found. For peak temperatures above 85–90 °C “preboiling” or cavitation activity appears and lesion distortion starts, causing small discrepancy between the measured and simulated temperature rises. From the measurements and simulations, it was shown that distortion of the lesion was caused by the “preboiling” activity. Conclusions: The present study demonstrated that for peak temperatures below 85–90 °C numerical simulation results are in excellent agreement with the experimental data in three dimensions. Both temperature rise and lesion size can be well predicted. Due to nonlinear effect the temperature in the focal region can be increased compared with the linear case. The current magnetic resonance imaging (MRI) resolution is not sufficient. Due to the inevitable averaging the measured

  18. Temperature elevation by HIFU in ex vivo porcine muscle: MRI measurement and simulation study

    International Nuclear Information System (INIS)

    Purpose: High-intensity focused ultrasound is a rapidly developing medical technology with a large number of potential clinical applications. Computational model can play a pivotal role in the planning and optimization of the treatment based on the patient's image. Nonlinear propagation effects can significantly affect the temperature elevation and should be taken into account. In order to investigate the importance of nonlinear propagation effects, nonlinear Westervelt equation was solved. Weak nonlinear propagation effects were studied. The purpose of this study was to investigate the correlation between the predicted and measured temperature elevations and lesion in a porcine muscle. Methods: The investigated single-element transducer has a focal length of 12 cm, an aperture of 8 cm, and frequency of 1.08 MHz. Porcine muscle was heated for 30 s by focused ultrasound transducer with an acoustic power in the range of 24–56 W. The theoretical model consists of nonlinear Westervelt equation with relaxation effects being taken into account and Pennes bioheat equation. Results: Excellent agreement between the measured and simulated temperature rises was found. For peak temperatures above 85–90 °C “preboiling” or cavitation activity appears and lesion distortion starts, causing small discrepancy between the measured and simulated temperature rises. From the measurements and simulations, it was shown that distortion of the lesion was caused by the “preboiling” activity. Conclusions: The present study demonstrated that for peak temperatures below 85–90 °C numerical simulation results are in excellent agreement with the experimental data in three dimensions. Both temperature rise and lesion size can be well predicted. Due to nonlinear effect the temperature in the focal region can be increased compared with the linear case. The current magnetic resonance imaging (MRI) resolution is not sufficient. Due to the inevitable averaging the measured

  19. Quantitative measurements of injections into porous media with contrast based MRI

    Science.gov (United States)

    Paulsen, J. L.; Donaldson, M. H.; Betancourt, S. S.; Song, Y.-Q.

    2011-09-01

    Porous flow occurs in a wide range of materials and applies to many commercially relevant applications such as oil recovery, chemical reactors and contaminant transport in soils. Typically, breakthrough and pressure curves of column floods are used in the laboratory characterization of these materials. These characterization methods lack the detail to easily and unambiguously resolve flow mechanisms with similar effects at the core scale that can dominate at the aquifer or oil field scale, as well as the effects of geometry that control the flow at interfaces as in a perforated well or the inlet of an improperly designed column. Non-invasive imaging techniques such as MRI have been shown to provide a far more detailed characterization of the properties of the solid matrix and flow, but usually focus on the intrinsic flow properties of porous media or matching a numerical model to a complex flow system. We show that these MRI techniques, utilizing paramagnetic tagging in combination with a carefully controlled and ideal flow system, can quantitatively characterize the effects of geometry and intrinsic flow properties for a point injection into a core. The use of a carefully controlled and 'idealized' system is essential to be able to isolate and match predicted effects from geometry and extract subtle flow processes omitted in the model that would be hidden in a more heterogeneous system. This approach provides not only a tool to understand the behavior of intentional boundary effects, but also one to diagnose the unintentional ones that often degrade the data from routine column flood measurements.

  20. Measurement of Knee Morphometrics Using MRI: A Comparative Study between ACL-Injured and Non-Injured Knees

    OpenAIRE

    Park, Jin Sung; Nam, Dae Chul; Kim, Dong Hee; Kim, Hyung Kan; Hwang, Sun Chul

    2012-01-01

    Purpose The purpose of this study is to find out the differences of distal femur morphology between the anterior cruciate ligament (ACL)-injured and the non-ACL injured on an magnetic resonance imaging (MRI), and the difference of bone structure by gender. Materials and Methods MRI Measurements of notch width (NW), bicondylar width (BCW), medial condyle width (MCW), lateral condyle width (LCW), medial-to-lateral condyle ratio (M:L ratio), and notch entrance width (NE) were taken from 120 subj...

  1. Reproducibility, and age, body-weight and gender dependency of candidate skeletal muscle MRI outcome measures in healthy volunteers

    International Nuclear Information System (INIS)

    Quantitative magnetic resonance imaging (MRI) can potentially meet the pressing need for objective, sensitive, reproducible outcome measures in neuromuscular disease trials. We tested, in healthy volunteers, the consistency, reliability and sensitivity to normal inter-subject variation of MRI methods targeted to lower limb muscle pathology to inform the design of practical but comprehensive MRI outcome measure protocols for use in imminent patient studies. Forty-seven healthy volunteers, age 21-81 years, were subject at 3T to three-point Dixon fat-fraction measurement, T1-relaxometry, T2-relaxometry and magnetisation transfer ratio (MTR) imaging at mid-thigh and mid-calf level bilaterally. Fifteen subjects underwent repeat imaging at 2 weeks. Mean between-muscle fat fraction and T2 differences were small, but significant (p 2 correlated positively, and MTR negatively with subject age in both the thigh and calf, with similar significant correlations with weight at thigh level only (p < 0.001 to p < 0.05). Scan-rescan and inter-observer intra-class correlation coefficients ranged between 0.62-0.84 and 0.79-0.99 respectively. Quantitative lower-limb muscle MRI using readily implementable methods was sensitive enough to demonstrate inter-muscle differences (small in health), and correlations with subject age and weight. In combination with high reliability, this strongly supports the suitability of these methods to provide longitudinal outcome measures in neuromuscular disease treatment trials. (orig.)

  2. State-Space Analysis of Granger-Geweke Causality Measures with Application to fMRI.

    Science.gov (United States)

    Solo, Victor

    2016-05-01

    The recent interest in the dynamics of networks and the advent, across a range of applications, of measuring modalities that operate on different temporal scales have put the spotlight on some significant gaps in the theory of multivariate time series. Fundamental to the description of network dynamics is the direction of interaction between nodes, accompanied by a measure of the strength of such interactions. Granger causality and its associated frequency domain strength measures (GEMs) (due to Geweke) provide a framework for the formulation and analysis of these issues. In pursuing this setup, three significant unresolved issues emerge. First, computing GEMs involves computing submodels of vector time series models, for which reliable methods do not exist. Second, the impact of filtering on GEMs has never been definitively established. Third, the impact of downsampling on GEMs has never been established. In this work, using state-space methods, we resolve all these issues and illustrate the results with some simulations. Our analysis is motivated by some problems in (fMRI) brain imaging, to which we apply it, but it is of general applicability. PMID:26942749

  3. Quantification of MRI measured myocardial perfusion reserve in healthy humans: a comparison with positron emission tomography

    DEFF Research Database (Denmark)

    Fritz-Hansen, Thomas; Hove, Jens D; Kofoed, Klaus F;

    2008-01-01

    during stress induced by dipyridamole in order to determine the myocardial perfusion reserve. Myocardial and blood time concentration curves obtained by Gd-DTPA-enhanced MRI and (13)N-ammonia PET were fitted by a two-compartment perfusion model. RESULTS: Mean perfusion values (+/-SD) derived from the MRI...

  4. Non-invasive liver iron concentration measurement by MRI : Comparison of two validated protocols

    NARCIS (Netherlands)

    Olthof, Allard W.; Sijens, Paul E.; Kreeftenberg, Herman G.; Kappert, Peter; van der Jagt, Eric J.; Oudkerk, Matthijs

    2009-01-01

    In the non-invasive determination of the liver iron concentration several validated MRI methods are available, two of which are compared in this study. Twenty-eight patients were examined by MRI and evaluated by the methods of Kreeftenberg et al. [Kreeftenberg Jr HG, Mcoyaart EL, Huizenga JR, Sluite

  5. Examining the Validity of Audience Accumulation Measures: A Comparison of MRI and SMRB.

    Science.gov (United States)

    Pavlik, John V.; Gerhart, Annette M.

    Concerned with the validity of the audience data reported by two major syndicated magazine readership services--Mediamark Research Inc. (MRI) and Simmons Market Research Bureau (SMRB)--a study examined the differences in MRI and SMRB calculations of reader turnover rates, which form the basis for estimating audience accumulation. Results indicated…

  6. Diagnostic performance of MRI measurements to assess hindfoot malalignment. An assessment of four measurement techniques

    International Nuclear Information System (INIS)

    To investigate the ability of coronal non-weight-bearing MR images to discriminate between normal and abnormal hindfoot alignment. Three different measurement techniques (calcaneal axis, medial/lateral calcaneal contour) based on weight-bearing hindfoot alignment radiographs were applied in 49 patients (mean, 48 years; range 21-76 years). Three groups of subjects were enrolled: (1) normal hindfoot alignment (0 -10 valgus); (2) abnormal valgus (>10 ); (3) any degree of varus hindfoot alignment. Hindfoot alignment was then measured on coronal MR images using four different measurement techniques (calcaneal axis, medial/lateral calcaneal contour, sustentaculum tangent). ROC analysis was performed to find the MR measurement with the greatest sensitivity and specificity for discrimination between normal and abnormal hindfoot alignment. The most accurate measurement on MR images to detect abnormal hindfoot valgus was the one using the medial calcaneal contour, reaching a sensitivity/specificity of 86 %/75 % using a cutoff value of >11 valgus. The most accurate measurement on MR images to detect abnormal hindfoot varus was the sustentaculum tangent, reaching a sensitivity/specificity of 91 %/71 % using a cutoff value of <12 valgus. It is possible to suspect abnormal hindfoot alignment on coronal non-weight-bearing MR images. (orig.)

  7. Diagnostic performance of MRI measurements to assess hindfoot malalignment. An assessment of four measurement techniques

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Florian M.; Hoffmann, Adrienne; Mamisch-Saupe, Nadja; Hodler, Juerg [University Hospital Balgrist and University of Zurich, Radiology, Zuerich (Switzerland); Farshad, Mazda; Espinosa, Norman [University Hospital Balgrist and University of Zurich, Department of Orthopaedic Surgery, Zuerich (Switzerland); Resnick, Donald [University of California San Diego, Department of Radiology, San Diego, CA (United States)

    2013-09-15

    To investigate the ability of coronal non-weight-bearing MR images to discriminate between normal and abnormal hindfoot alignment. Three different measurement techniques (calcaneal axis, medial/lateral calcaneal contour) based on weight-bearing hindfoot alignment radiographs were applied in 49 patients (mean, 48 years; range 21-76 years). Three groups of subjects were enrolled: (1) normal hindfoot alignment (0 -10 valgus); (2) abnormal valgus (>10 ); (3) any degree of varus hindfoot alignment. Hindfoot alignment was then measured on coronal MR images using four different measurement techniques (calcaneal axis, medial/lateral calcaneal contour, sustentaculum tangent). ROC analysis was performed to find the MR measurement with the greatest sensitivity and specificity for discrimination between normal and abnormal hindfoot alignment. The most accurate measurement on MR images to detect abnormal hindfoot valgus was the one using the medial calcaneal contour, reaching a sensitivity/specificity of 86 %/75 % using a cutoff value of >11 valgus. The most accurate measurement on MR images to detect abnormal hindfoot varus was the sustentaculum tangent, reaching a sensitivity/specificity of 91 %/71 % using a cutoff value of <12 valgus. It is possible to suspect abnormal hindfoot alignment on coronal non-weight-bearing MR images. (orig.)

  8. Quantification of MRI measured myocardial perfusion reserve in healthy humans: A comparison with positron emission tomography

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Hove, J.D.; Kofoed, K.F.;

    2008-01-01

    during stress induced by dipyridamole in order to determine the myocardial perfusion reserve. Myocardial and blood time concentration curves obtained by Gd-DTPA-enhanced MRI and N-13-ammonia PET were fitted by a two-compartment perfusion model. Results: Mean perfusion values (+/- SD) derived from the MRI......Purpose: To validate a noninvasive quantitative MRI technique, the K-i perfusion method, for myocardial perfusion in humans using N-13-ammonia PET as a reference method. Materials and Methods: Ten healthy males (64 +/- 8 years) were examined with combined PET and MRI perfusion imaging at rest and...... method at rest and at hyperemia were 80 +/- 20 and 183 +/- 56 mL/min/100 g, respectively. The same data for PET were 71 +/- 16 and 203 +/- 67 mL/min/100 g. A linear relationship was observed between MRI and PET-derived myocardial perfusion reserve for regional and global data. Linear regression for the...

  9. MRI of Stroke Recovery

    OpenAIRE

    Jiang, Quan; Zhang, Zheng Gang; Chopp, Michael

    2009-01-01

    MRI is a vital tool for the measurement of acute stroke and has been used to visualize changes in activation patterns during stroke recovery. There is emerging interest on using MRI to monitor the structural substrates of spontaneous recovery and neurorestorative treatment of stroke. In this review, we describe the use of MRI and its associated challenges to measure vascular and neuronal remodeling in response to spontaneous and therapy-induced stroke recovery. We demonstrate that MRI methodo...

  10. Repeatability of cardiac-MRI-measured right ventricular size and function in congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Rowan; Salem, Yishay [Mount Sinai School of Medicine, Division of Pediatric Cardiology, New York, NY (United States); Shah, Amee; Lai, Wyman W. [Morgan Stanley Children' s Hospital of New York Presbyterian, New York, NY (United States); Nielsen, James C. [Mount Sinai School of Medicine, Division of Pediatric Cardiology, New York, NY (United States); Mount Sinai Children' s Heart Center, Box 1201, New York, NY (United States)

    2011-08-15

    The measurement error for right ventricular (RV) size and function assessed by cardiac MRI (CMRI) in congenital heart disease has not been fully characterized. As CMRI parameters are being increasingly utilized to make clinical decisions, defining error in the clinical setting is critical. This investigation examines the repeatability of CMRI for RV size and function. Forty consecutive people with congenital heart disease involving the RV were retrospectively identified. Contouring of RV volumes was performed by two expert CMRI clinicians. The coefficient of variability and repeatability coefficients were calculated. Repeatability coefficients were multiplied by the mean value for each group studied to define a threshold beyond which measurement error was unlikely to be responsible. The variability for indexed RV end-diastolic volume = 3.2% and 3.3% for intra- and interobserver comparisons, respectively. The repeatability coefficients were 13.2% and 14.9% for intra- and interobserver comparisons, which yielded threshold values of 15.1 ml/m{sup 2} and 20.2 ml/m{sup 2}, respectively. For RV ejection fraction (EF), the repeatability coefficients for intra- and interobserver comparisons were 5.0% and 6.0%, which resulted in threshold values of 2.6 EF% and 3.0 EF%. The threshold values generated can be used during serial assessment of RV size and function. (orig.)

  11. Repeatability of cardiac-MRI-measured right ventricular size and function in congenital heart disease

    International Nuclear Information System (INIS)

    The measurement error for right ventricular (RV) size and function assessed by cardiac MRI (CMRI) in congenital heart disease has not been fully characterized. As CMRI parameters are being increasingly utilized to make clinical decisions, defining error in the clinical setting is critical. This investigation examines the repeatability of CMRI for RV size and function. Forty consecutive people with congenital heart disease involving the RV were retrospectively identified. Contouring of RV volumes was performed by two expert CMRI clinicians. The coefficient of variability and repeatability coefficients were calculated. Repeatability coefficients were multiplied by the mean value for each group studied to define a threshold beyond which measurement error was unlikely to be responsible. The variability for indexed RV end-diastolic volume = 3.2% and 3.3% for intra- and interobserver comparisons, respectively. The repeatability coefficients were 13.2% and 14.9% for intra- and interobserver comparisons, which yielded threshold values of 15.1 ml/m2 and 20.2 ml/m2, respectively. For RV ejection fraction (EF), the repeatability coefficients for intra- and interobserver comparisons were 5.0% and 6.0%, which resulted in threshold values of 2.6 EF% and 3.0 EF%. The threshold values generated can be used during serial assessment of RV size and function. (orig.)

  12. Comparison of 3D orientation distribution functions measured with confocal microscopy and diffusion MRI.

    Science.gov (United States)

    Schilling, Kurt; Janve, Vaibhav; Gao, Yurui; Stepniewska, Iwona; Landman, Bennett A; Anderson, Adam W

    2016-04-01

    The ability of diffusion MRI (dMRI) fiber tractography to non-invasively map three-dimensional (3D) anatomical networks in the human brain has made it a valuable tool in both clinical and research settings. However, there are many assumptions inherent to any tractography algorithm that can limit the accuracy of the reconstructed fiber tracts. Among them is the assumption that the diffusion-weighted images accurately reflect the underlying fiber orientation distribution (FOD) in the MRI voxel. Consequently, validating dMRI's ability to assess the underlying fiber orientation in each voxel is critical for its use as a biomedical tool. Here, using post-mortem histology and confocal microscopy, we present a method to perform histological validation of orientation functions in 3D, which has previously been limited to two-dimensional analysis of tissue sections. We demonstrate the ability to extract the 3D FOD from confocal z-stacks, and quantify the agreement between the MRI estimates of orientation information obtained using constrained spherical deconvolution (CSD) and the true geometry of the fibers. We find an orientation error of approximately 6° in voxels containing nearly parallel fibers, and 10-11° in crossing fiber regions, and note that CSD was unable to resolve fibers crossing at angles below 60° in our dataset. This is the first time that the 3D white matter orientation distribution is calculated from histology and compared to dMRI. Thus, this technique serves as a gold standard for dMRI validation studies - providing the ability to determine the extent to which the dMRI signal is consistent with the histological FOD, and to establish how well different dMRI models can predict the ground truth FOD. PMID:26804781

  13. Anatomic guidelines defined by reformatting images on MRI for volume measurement of amygdala and hippocampus

    International Nuclear Information System (INIS)

    Twelve patients with intractable partial epilepsy underwent MR scans at the Epilepsy Center of the Johns Hopkins Hospital. There were five women and seven men, ranging in age from five to 51 years (mean age: 26 years). Coronal images were obtained using a 3-D SPGR. The coronal images were transferred to an Allegro 5.1 workstation, and reformatted along the cardinal axes (axial and sagittal) in multiple view points. The anterior end of the amygdala was measured at the level just posterior to the disappearance of the temporal stem. The semilunar gyrus of the amygdala was separated from the ambient gyrus by the semianular sulcus that forms the boundary between the amygdala and the entorhinal cortex. The delineation of the hippocampal formation included the subicular complex, hippocampal proper, dentate gyrus, alveus, and fimbria. The uncal cleft separated the uncus above from the parahippocampal gyrus below. The roof of this cleft was formed by the hippocampus and the dentate gyrus, and the floor, by the presubiculum and subiculum. Although using some guidelines, strictly separating the hippocampal head from the posterior part of the amygdala was not feasible as was previously reported, because of the isointensity on MRI between the cortex of the amygdala and the hippocampus. The most posterior portion of the hippocampus was measured at the level of the subsplenial gyri, just below the splenium of the corpus callosum, to measure the hippocampal volume in its near totality. Therefore, it is reliable, and clinically useful, to measure the combined total volume of the amygdala and the hippocampus when comparing results with those of other centers. (S.Y.)

  14. CT- and MRI-based volumetry of resected liver specimen: Comparison to intraoperative volume and weight measurements and calculation of conversion factors

    International Nuclear Information System (INIS)

    Objective: To compare virtual volume to intraoperative volume and weight measurements of resected liver specimen and calculate appropriate conversion factors to reach better correlation. Methods: Preoperative (CT-group, n = 30; MRI-group, n = 30) and postoperative MRI (n = 60) imaging was performed in 60 patients undergoing partial liver resection. Intraoperative volume and weight of the resected liver specimen was measured. Virtual volume measurements were performed by two readers (R1,R2) using dedicated software. Conversion factors were calculated. Results: Mean intraoperative resection weight/volume: CT: 855 g/852 mL; MRI: 872 g/860 mL. Virtual resection volume: CT: 960 mL(R1), 982 mL(R2); MRI: 1112 mL(R1), 1115 mL(R2). Strong positive correlation for both readers between intraoperative and virtual measurements, mean of both readers: CT: R = 0.88(volume), R = 0.89(weight); MRI: R = 0.95(volume), R = 0.92(weight). Conversion factors: 0.85(CT), 0.78(MRI). Conclusion: CT- or MRI-based volumetry of resected liver specimen is accurate and recommended for preoperative planning. A conversion of the result is necessary to improve intraoperative and virtual measurement correlation. We found 0.85 for CT- and 0.78 for MRI-based volumetry the most appropriate conversion factors.

  15. Quantitative MRI for hepatic fat fraction and T2* measurement in pediatric patients with non-alcoholic fatty liver disease

    International Nuclear Information System (INIS)

    Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in children. The gold standard for diagnosis is liver biopsy. MRI is a non-invasive imaging method to provide quantitative measurement of hepatic fat content. The methodology is particularly appealing for the pediatric population because of its rapidity and radiation-free imaging techniques. To develop a multi-point Dixon MRI method with multi-interference models (multi-fat-peak modeling and bi-exponential T2* correction) for accurate hepatic fat fraction (FF) and T2* measurements in pediatric patients with NAFLD. A phantom study was first performed to validate the accuracy of the MRI fat fraction measurement by comparing it with the chemical fat composition of the ex-vivo pork liver-fat homogenate. The most accurate model determined from the phantom study was used for fat fraction and T2* measurements in 52 children and young adults referred from the pediatric hepatology clinic with suspected or identified NAFLD. Separate T2* values of water (T2*W) and fat (T2*F) components derived from the bi-exponential fitting were evaluated and plotted as a function of fat fraction. In ten patients undergoing liver biopsy, we compared histological analysis of liver fat fraction with MRI fat fraction. In the phantom study the 6-point Dixon with 5-fat-peak, bi-exponential T2* modeling demonstrated the best precision and accuracy in fat fraction measurements compared with other methods. This model was further calibrated with chemical fat fraction and applied in patients, where similar patterns were observed as in the phantom study that conventional 2-point and 3-point Dixon methods underestimated fat fraction compared to the calibrated 6-point 5-fat-peak bi-exponential model (P W (27.9 ± 3.5 ms) decreased, whereas T2*F (20.3 ± 5.5 ms) increased; and T2*W and T2*F became increasingly more similar when fat fraction was higher than 15-20%. Histological fat fraction measurements in ten

  16. Quantitative MRI for hepatic fat fraction and T2* measurement in pediatric patients with non-alcoholic fatty liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Jie; Rigsby, Cynthia K.; Donaldson, James S. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States); Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Fishbein, Mark H. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Division of Gastroenterology, Hepatology, and Nutrition, Chicago, IL (United States); Zhang, Gang [Ann and Robert H. Lurie Children' s Hospital of Chicago, Biostatistics Research Core, Chicago, IL (United States); Schoeneman, Samantha E. [Ann and Robert H. Lurie Children' s Hospital of Chicago, Department of Medical Imaging, Chicago, IL (United States)

    2014-11-15

    Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in children. The gold standard for diagnosis is liver biopsy. MRI is a non-invasive imaging method to provide quantitative measurement of hepatic fat content. The methodology is particularly appealing for the pediatric population because of its rapidity and radiation-free imaging techniques. To develop a multi-point Dixon MRI method with multi-interference models (multi-fat-peak modeling and bi-exponential T2* correction) for accurate hepatic fat fraction (FF) and T2* measurements in pediatric patients with NAFLD. A phantom study was first performed to validate the accuracy of the MRI fat fraction measurement by comparing it with the chemical fat composition of the ex-vivo pork liver-fat homogenate. The most accurate model determined from the phantom study was used for fat fraction and T2* measurements in 52 children and young adults referred from the pediatric hepatology clinic with suspected or identified NAFLD. Separate T2* values of water (T2*{sub W}) and fat (T2*{sub F}) components derived from the bi-exponential fitting were evaluated and plotted as a function of fat fraction. In ten patients undergoing liver biopsy, we compared histological analysis of liver fat fraction with MRI fat fraction. In the phantom study the 6-point Dixon with 5-fat-peak, bi-exponential T2* modeling demonstrated the best precision and accuracy in fat fraction measurements compared with other methods. This model was further calibrated with chemical fat fraction and applied in patients, where similar patterns were observed as in the phantom study that conventional 2-point and 3-point Dixon methods underestimated fat fraction compared to the calibrated 6-point 5-fat-peak bi-exponential model (P < 0.0001). With increasing fat fraction, T2*{sub W} (27.9 ± 3.5 ms) decreased, whereas T2*{sub F} (20.3 ± 5.5 ms) increased; and T2*{sub W} and T2*{sub F} became increasingly more similar when fat

  17. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Waahlin, Anders

    2012-07-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  18. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    International Nuclear Information System (INIS)

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  19. Quantitative assessment of myocardial motion from displacement measurements derived from velocity encoded MRI

    OpenAIRE

    Lutz Anja; Paul Jan; Etyngier Patrick; Bornstedt Axel; Nienhaus Gerd; Bernhardt Peter; Rottbauer Wolfgang; Rasche Volker

    2012-01-01

    International audience It is objective of this study to investigate the potential of velocity encoded MRI (TPM) to derive quantitative parameters based on local displacement information for the automatic assessment of mechanical asynchrony in CRT patients.

  20. MRI Measures of Hippocampus in Mild Cognitive Impairment and Alzheimer Patients

    Directory of Open Access Journals (Sweden)

    Çağatay Öncel

    2011-12-01

    Full Text Available OBJECTIVE: In this study we aimed to compare the hippocampal volumes of patients diagnosed as Alzheimer’s Disease (AD, Minimal Cognitive Impairment (MCI and the healthy objects. We also tried to demonstrate whether there was a possible correlation between the cognitive tests and the hippocampal volumes. METHODS: Minimental State Examination, Adas-Cog and Global Deterioration Scale were administrated to the patients having Alzheimer’s Disease (n=20. We also performed Minimental State Examination, and Adas-Cog to MCI patients (n=20 and Minimental State Examination to the healthy control group (n=18. Both right and left hippocampal volumes were measured by a three dimensioned Surf Driver programm with the support of cranial magnetic resonance imaging (MRI. RESULTS: Both right and left hippocampal volumes of the Alzheimer’s Disease group were significantly smaller than the MCI and the control groups. Bilaterally hippocampal volumes of MCI group were also smaller than the control group. (Hippocampal volumes; AD 0.05. CONCLUSION: : Surf Driver method succesfully demonstrated the relative hippocampal atrophy in the AD and the MCI groups when compared with the healthy controls.

  1. fMRI Validation of fNIRS Measurements During a Naturalistic Task.

    Science.gov (United States)

    Noah, J Adam; Ono, Yumie; Nomoto, Yasunori; Shimada, Sotaro; Tachibana, Atsumichi; Zhang, Xian; Bronner, Shaw; Hirsch, Joy

    2015-01-01

    We present a method to compare brain activity recorded with near-infrared spectroscopy (fNIRS) in a dance video game task to that recorded in a reduced version of the task using fMRI (functional magnetic resonance imaging). Recently, it has been shown that fNIRS can accurately record functional brain activities equivalent to those concurrently recorded with functional magnetic resonance imaging for classic psychophysical tasks and simple finger tapping paradigms. However, an often quoted benefit of fNIRS is that the technique allows for studying neural mechanisms of complex, naturalistic behaviors that are not possible using the constrained environment of fMRI. Our goal was to extend the findings of previous studies that have shown high correlation between concurrently recorded fNIRS and fMRI signals to compare neural recordings obtained in fMRI procedures to those separately obtained in naturalistic fNIRS experiments. Specifically, we developed a modified version of the dance video game Dance Dance Revolution (DDR) to be compatible with both fMRI and fNIRS imaging procedures. In this methodology we explain the modifications to the software and hardware for compatibility with each technique as well as the scanning and calibration procedures used to obtain representative results. The results of the study show a task-related increase in oxyhemoglobin in both modalities and demonstrate that it is possible to replicate the findings of fMRI using fNIRS in a naturalistic task. This technique represents a methodology to compare fMRI imaging paradigms which utilize a reduced-world environment to fNIRS in closer approximation to naturalistic, full-body activities and behaviors. Further development of this technique may apply to neurodegenerative diseases, such as Parkinson's disease, late states of dementia, or those with magnetic susceptibility which are contraindicated for fMRI scanning. PMID:26132365

  2. A novel approach to calibrate the Hemodynamic Model using functional Magnetic Resonance Imaging (fMRI) measurements

    KAUST Repository

    Khoram, Nafiseh

    2016-01-21

    Background The calibration of the hemodynamic model that describes changes in blood flow and blood oxygenation during brain activation is a crucial step for successfully monitoring and possibly predicting brain activity. This in turn has the potential to provide diagnosis and treatment of brain diseases in early stages. New Method We propose an efficient numerical procedure for calibrating the hemodynamic model using some fMRI measurements. The proposed solution methodology is a regularized iterative method equipped with a Kalman filtering-type procedure. The Newton component of the proposed method addresses the nonlinear aspect of the problem. The regularization feature is used to ensure the stability of the algorithm. The Kalman filter procedure is incorporated here to address the noise in the data. Results Numerical results obtained with synthetic data as well as with real fMRI measurements are presented to illustrate the accuracy, robustness to the noise, and the cost-effectiveness of the proposed method. Comparison with Existing Method(s) We present numerical results that clearly demonstrate that the proposed method outperforms the Cubature Kalman Filter (CKF), one of the most prominent existing numerical methods. Conclusion We have designed an iterative numerical technique, called the TNM-CKF algorithm, for calibrating the mathematical model that describes the single-event related brain response when fMRI measurements are given. The method appears to be highly accurate and effective in reconstructing the BOLD signal even when the measurements are tainted with high noise level (as high as 30%).

  3. Concordance of Epileptic Networks Associated with Epileptic Spikes Measured by High-Density EEG and Fast fMRI

    OpenAIRE

    Jäger, Vera; Dümpelmann, Matthias; LeVan, Pierre; Ramantani, Georgia; Mader, Irina; Schulze-Bonhage, Andreas; Jacobs, Julia

    2015-01-01

    Objective The present study aims to investigate whether a newly developed fast fMRI called MREG (magnetic resonance encephalography) measures metabolic changes related to interictal epileptic discharges (IED). For this purpose BOLD changes are correlated with the IED distribution and variability. Methods Patients with focal epilepsy underwent EEG-MREG using a 64 channel cap. IED voltage maps were generated using 32 and 64 channels and compared regarding their correspondence to the BOLD respon...

  4. Reproducibility, and age, body-weight and gender dependency of candidate skeletal muscle MRI outcome measures in healthy volunteers

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Jasper M.; Reilly, Mary M.; Hanna, Michael G. [UCL Institute of Neurology, Medical Research Council Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, London (United Kingdom); Sinclair, Christopher D.J.; Yousry, Tarek A.; Thornton, John S. [UCL Institute of Neurology, Medical Research Council Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, London (United Kingdom); UCL Institute of Neurology, Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, London (United Kingdom); Fischmann, Arne [University of Basel Hospital, Department of Radiology, Division of Diagnostic and Interventional Neuroradiology, Basel (Switzerland)

    2014-07-15

    Quantitative magnetic resonance imaging (MRI) can potentially meet the pressing need for objective, sensitive, reproducible outcome measures in neuromuscular disease trials. We tested, in healthy volunteers, the consistency, reliability and sensitivity to normal inter-subject variation of MRI methods targeted to lower limb muscle pathology to inform the design of practical but comprehensive MRI outcome measure protocols for use in imminent patient studies. Forty-seven healthy volunteers, age 21-81 years, were subject at 3T to three-point Dixon fat-fraction measurement, T{sub 1}-relaxometry, T{sub 2}-relaxometry and magnetisation transfer ratio (MTR) imaging at mid-thigh and mid-calf level bilaterally. Fifteen subjects underwent repeat imaging at 2 weeks. Mean between-muscle fat fraction and T{sub 2} differences were small, but significant (p < 0.001). Fat fraction and T{sub 2} correlated positively, and MTR negatively with subject age in both the thigh and calf, with similar significant correlations with weight at thigh level only (p < 0.001 to p < 0.05). Scan-rescan and inter-observer intra-class correlation coefficients ranged between 0.62-0.84 and 0.79-0.99 respectively. Quantitative lower-limb muscle MRI using readily implementable methods was sensitive enough to demonstrate inter-muscle differences (small in health), and correlations with subject age and weight. In combination with high reliability, this strongly supports the suitability of these methods to provide longitudinal outcome measures in neuromuscular disease treatment trials. (orig.)

  5. Determinants of renal tissue oxygenation as measured with BOLD-MRI in chronic kidney disease and hypertension in humans.

    OpenAIRE

    Pruijm, Menno; Hofmann, Lucie; Piskunowicz, Maciej; Muller, Marie-Eve; Zweiacker, Carole; Bassi, Isabelle; Vogt, Bruno; Stuber, Matthias; Burnier, Michel

    2014-01-01

    Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullar...

  6. Determinants of Renal Tissue Oxygenation as Measured with BOLD-MRI in Chronic Kidney Disease and Hypertension in Humans

    OpenAIRE

    Menno Pruijm; Lucie Hofmann; Maciej Piskunowicz; Marie-Eve Muller; Carole Zweiacker; Isabelle Bassi; Bruno Vogt; Matthias Stuber; Michel Burnier

    2014-01-01

    Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullar...

  7. In vivo measurements of relaxation process in the human liver by MRI. The role of respiratory gating/triggering

    DEFF Research Database (Denmark)

    Thomsen, C; Henriksen, O; Ring, P

    1988-01-01

    In vivo estimation of relaxation processes in the liver by magnetic resonance imaging (MRI) may be helpful for characterization of various pathological conditions in the liver. However, such measurements may be significantly hampered by movement of the liver with the respiration. The effect of...... synchronization of data acquisition to the respiratory cycle on measured T1- and T2-relaxation curves was studied in normal subjects, patients with diffuse liver disease, and patients with focal liver pathology. Multi spin echo sequences with five different repetition times were used. The measurements were...

  8. Cerebral hemodynamic changes measured by gradient-echo or spin-echo bolus tracking and its correlation to changes in ICA blood flow measured by phase-mapping MRI

    DEFF Research Database (Denmark)

    Marstrand, J.R.; Rostrup, Egill; Garde, Ellen; Larsson, Henrik B.W.

    2001-01-01

    Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC-MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase-mapping. Also examined was...

  9. Multisensory integration of dynamic emotional faces and voices: method for simultaneous EEG-fMRI measurements

    Directory of Open Access Journals (Sweden)

    Patrick David Schelenz

    2013-11-01

    Full Text Available Combined EEG-fMRI analysis correlates time courses from single electrodes or independent EEG components with the hemodynamic response. Implementing information from only one electrode, however, may miss relevant information from complex electrophysiological networks. Component based analysis, in turn, depends on a priori knowledge of the signal topography. Complex designs such as studies on multisensory integration of emotions investigate subtle differences in distributed networks based on only a few trials per condition. Thus, they require a sensitive and comprehensive approach which does not rely on a-priori knowledge about the underlying neural processes. In this pilot study, feasibility and sensitivity of source localization-driven analysis for EEG-fMRI was tested using a multisensory integration paradigm. Dynamic audiovisual stimuli consisting of emotional talking faces and pseudowords with emotional prosody were rated in a delayed response task. The trials comprised affectively congruent and incongruent displays.In addition to event-locked EEG and fMRI analyses, induced oscillatory EEG responses at estimated cortical sources and in specific temporo-spectral windows were correlated with the corresponding BOLD responses. EEG analysis showed high data quality with less than 10% trial rejection. In an early time window, alpha oscillations were suppressed in bilateral occipital cortices and fMRI analysis confirmed high data quality with reliable activation in auditory, visual and frontal areas to the presentation of multisensory stimuli. In line with previous studies, we obtained reliable correlation patterns for event locked occipital alpha suppression and BOLD signal time course.Our results suggest a valid methodological approach to investigate complex stimuli using the present source localization driven method for EEG-fMRI. This novel procedure may help to investigate combined EEG-fMRI data from novel complex paradigms with high spatial and

  10. Multi-parametric MRI of rectal cancer – Do quantitative functional MR measurements correlate with radiologic and pathologic tumor stages?

    Energy Technology Data Exchange (ETDEWEB)

    Attenberger, U.I. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Pilz, L.R. [Medical Faculty Mannheim, University of Heidelberg (Germany); Morelli, J.N. [Scott and White Memorial Hospital and Clinic, Temple, TX (United States); Hausmann, D., E-mail: daniel.hausmann@medma.uni-heidelberg.de [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany); Doyon, F. [Department of Surgery, University Medical Center Mannheim (Germany); Hofheinz, R. [Department of Oncology, University Medical Center Mannheim (Germany); Kienle, P.; Post, S. [Department of Surgery, University Medical Center Mannheim (Germany); Michaely, H.J.; Schoenberg, S.O.; Dinter, D.J. [Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim (Germany)

    2014-07-15

    Purpose: The purpose of this study is two-fold. First, to evaluate, whether functional rectal MRI techniques can be analyzed in a reproducible manner by different readers and second, to assess whether different clinical and pathologic T and N stages can be differentiated by functional MRI measurements. Materials and methods: 54 patients (38 men, 16 female; mean age 63.2 ± 12.2 years) with pathologically proven rectal cancer were included in this retrospective IRB-approved study. All patients were referred for a multi-parametric MRI protocol on a 3 Tesla MR-system, consisting of a high-resolution, axial T2 TSE sequence, DWI and perfusion imaging (plasma flow –s PF{sub Tumor}) prior to any treatment. Two experienced radiologists evaluated the MRI measurements, blinded to clinical data and outcome. Inter-reader correlation and the association of functional MRI parameters with c- and p-staging were analyzed. Results: The inter-reader correlation for lymph node (ρ 0.76–0.94; p < 0.0002) and primary tumor (ρ 0.78–0.92; p < 0.0001) apparent diffusion coefficient and plasma flow (PF) values was good to very good. PF{sub Tumor} values decreased with cT stage with significant differences identified between cT2 and cT3 tumors (229 versus 107.6 ml/100 ml/min; p = 0.05). ADC{sub Tumor} values did not differ significantly. No substantial discrepancies in lymph node ADC{sub Ln} values or short axis diameter were found among cN1-3 stages, whereas PF{sub Ln} values were distinct between cN1 versus cN2 stages (p = 0.03). In the patients without neoadjuvant RCT no statistically significant differences in the assessed functional parameters on the basis of pathologic stage were found. Conclusion: This study illustrates that ADC as well as MR perfusion values can be analyzed with good interobserver agreement in patients with rectal cancer. Moreover, MR perfusion parameters may allow accurate differentiation of tumor stages. Both findings suggest that functional MRI parameters

  11. Multi-parametric MRI of rectal cancer – Do quantitative functional MR measurements correlate with radiologic and pathologic tumor stages?

    International Nuclear Information System (INIS)

    Purpose: The purpose of this study is two-fold. First, to evaluate, whether functional rectal MRI techniques can be analyzed in a reproducible manner by different readers and second, to assess whether different clinical and pathologic T and N stages can be differentiated by functional MRI measurements. Materials and methods: 54 patients (38 men, 16 female; mean age 63.2 ± 12.2 years) with pathologically proven rectal cancer were included in this retrospective IRB-approved study. All patients were referred for a multi-parametric MRI protocol on a 3 Tesla MR-system, consisting of a high-resolution, axial T2 TSE sequence, DWI and perfusion imaging (plasma flow –s PFTumor) prior to any treatment. Two experienced radiologists evaluated the MRI measurements, blinded to clinical data and outcome. Inter-reader correlation and the association of functional MRI parameters with c- and p-staging were analyzed. Results: The inter-reader correlation for lymph node (ρ 0.76–0.94; p < 0.0002) and primary tumor (ρ 0.78–0.92; p < 0.0001) apparent diffusion coefficient and plasma flow (PF) values was good to very good. PFTumor values decreased with cT stage with significant differences identified between cT2 and cT3 tumors (229 versus 107.6 ml/100 ml/min; p = 0.05). ADCTumor values did not differ significantly. No substantial discrepancies in lymph node ADCLn values or short axis diameter were found among cN1-3 stages, whereas PFLn values were distinct between cN1 versus cN2 stages (p = 0.03). In the patients without neoadjuvant RCT no statistically significant differences in the assessed functional parameters on the basis of pathologic stage were found. Conclusion: This study illustrates that ADC as well as MR perfusion values can be analyzed with good interobserver agreement in patients with rectal cancer. Moreover, MR perfusion parameters may allow accurate differentiation of tumor stages. Both findings suggest that functional MRI parameters may help to discriminate T and

  12. Assessment of CAD-generated tumor volumes measured using MRI in breast cancers before and after neoadjuvant chemotherapy

    International Nuclear Information System (INIS)

    Objective: To evaluate inter-observer agreement and the predictive value of tumor size measurements using MRI for breast cancer under neoadjuvant chemotherapy (NAC) by comparing the measurements of the longest diameters (LD), total enhanced volumes (TEV) and washout volumes (WOV). Methods: Thirty-seven female breast cancer patients were prospectively enrolled from August 2008 to October 2010. Two of these patients had locally advanced disease. MRI examinations were acquired within 2 weeks before and after NAC. Interim scans were also conducted in 30 patients. Tumor resection was undertaken within 2 weeks after the cessation of NAC. MRI images were independently measured for LD, TEV and WOV by two experienced radiologists. Inter-observer agreement was evaluated using concordance correlation coefficients (CCCs). Tumor sizes after NAC were evaluated relative to their initial sizes for early prediction of a pathological complete response (pCR). Results: The CCCs were 0.93 (CI: 0.90–0.95) for LD, 0.98 (CI: 0.97–0.98) for TEV and 0.99 (CI: 0.991–0.996) for WOV. All measurements had high inter-observer agreement, but the CCCs were significantly increased in the aforementioned order (P < 0.0001). WOV measured after the completion of chemotherapy had significant discriminating ability (P = 0.0056) when evaluated using receiver operating characteristic analysis, and was found to be superior to LD (P = 0.045). The average WOV size was significantly smaller in pCR cases than in non-pCR cases (P = 0.016). Conclusion: Computer-aided detection-generated tumor volumes had significantly higher inter-observer concordance than conventional LD measurements. WOV measurements had the highest concordance, and WOV could better predict pCR after NAC at smaller tumor sizes

  13. fMRI Data Analysis Using Dempster-Shafer Method with Estimating Voxel Selectivity by Belief Measure

    Directory of Open Access Journals (Sweden)

    ATTIA Abdelouahab

    2016-01-01

    Full Text Available In the functional Magnetic Resonance Imaging (fMRI data analysis, detecting the activated voxels is a challenging research problem where the existing methods have shown some limits. We propose a new method wherein brain mapping is done based on Dempster-Shafer theory of evidence (DS that is a useful method in uncertain representation analysis. Dempster-Shafer allows finding the activated regions by checking the activated voxels in fMRI data. The activated brain areas related to a given stimulus are detected by using a belief measure as a metric for evaluating activated voxels. To test the performance of the proposed method, artificial and real auditory data have been employed. The comparison of the introduced method with the t-test and GLM method has clearly shown that the proposed method can provide a higher correct detection of activated voxels.

  14. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 5: an international multicenter reliability study using computerized MRI erosion volume measurements

    DEFF Research Database (Denmark)

    Bird, P; Ejbjerg, B; McQueen, F;

    2003-01-01

    Scoring erosions on magnetic resonance imaging (MRI) is one method of estimating damage in patients with rheumatoid arthritis (RA), but it has limitations. The aim of this pilot study was to assess the feasibility and inter-reader reliability of computer assisted erosion volume estimation in...... patients with RA. Intra-reader and inter-occasion reliability was also assessed, and different slice thicknesses were compared in terms of erosion volume estimation. A 3 mm slice thickness 3D gradient-echo sequence followed by a 1 mm sequence was performed at baseline and repeated within 24 h with...... volume estimation method was more time consuming, taking roughly 5 times as long as the scoring method. Computerized MRI erosion volume measurements are feasible, with high intra-observer and inter-occasion reliabilities. Despite high ICC, the inter-observer reliability is not sufficient for multicenter...

  15. MRI-based measurements of respiratory motion variability and assessment of imaging strategies for radiotherapy planning

    International Nuclear Information System (INIS)

    Respiratory organ motion has a significant impact on the planning and delivery of radiotherapy (RT) treatment for lung cancer. Currently widespread techniques, such as 4D-computed tomography (4DCT), cannot be used to measure variability of this motion from one cycle to the next. In this paper, we describe the use of fast magnetic resonance imaging (MRI) techniques to investigate the intra- and inter-cycle reproducibility of respiratory motion and also to estimate the level of errors that may be introduced into treatment delivery by using various breath-hold imaging strategies during lung RT planning. A reference model of respiratory motion is formed to enable comparison of different breathing cycles at any arbitrary position in the respiratory cycle. This is constructed by using free-breathing images from the inhale phase of a single breathing cycle, then co-registering the images, and thereby tracking landmarks. This reference model is then compared to alternative models constructed from images acquired during the exhale phase of the same cycle and the inhale phase of a subsequent cycle, to assess intra- and inter-cycle variability ('hysteresis' and 'reproducibility') of organ motion. The reference model is also compared to a series of models formed from breath-hold data at exhale and inhale. Evaluation of these models is carried out on data from ten healthy volunteers and five lung cancer patients. Free-breathing models show good levels of intra- and inter-cycle reproducibility across the tidal breathing range. Mean intra-cycle errors in the position of organ surface landmarks of 1.5(1.4)-3.5(3.3) mm for volunteers and 2.8(1.8)-5.2(5.2) mm for patients. Equivalent measures of inter-cycle variability across this range are 1.7(1.0)-3.9(3.3) mm for volunteers and 2.8(1.8)-3.3(2.2) mm for patients. As expected, models based on breath-hold sequences do not represent normal tidal motion as well as those based on free-breathing data, with mean errors of 4

  16. MRI-based measurements of respiratory motion variability and assessment of imaging strategies for radiotherapy planning

    Science.gov (United States)

    Blackall, J. M.; Ahmad, S.; Miquel, M. E.; McClelland, J. R.; Landau, D. B.; Hawkes, D. J.

    2006-09-01

    Respiratory organ motion has a significant impact on the planning and delivery of radiotherapy (RT) treatment for lung cancer. Currently widespread techniques, such as 4D-computed tomography (4DCT), cannot be used to measure variability of this motion from one cycle to the next. In this paper, we describe the use of fast magnetic resonance imaging (MRI) techniques to investigate the intra- and inter-cycle reproducibility of respiratory motion and also to estimate the level of errors that may be introduced into treatment delivery by using various breath-hold imaging strategies during lung RT planning. A reference model of respiratory motion is formed to enable comparison of different breathing cycles at any arbitrary position in the respiratory cycle. This is constructed by using free-breathing images from the inhale phase of a single breathing cycle, then co-registering the images, and thereby tracking landmarks. This reference model is then compared to alternative models constructed from images acquired during the exhale phase of the same cycle and the inhale phase of a subsequent cycle, to assess intra- and inter-cycle variability ('hysteresis' and 'reproducibility') of organ motion. The reference model is also compared to a series of models formed from breath-hold data at exhale and inhale. Evaluation of these models is carried out on data from ten healthy volunteers and five lung cancer patients. Free-breathing models show good levels of intra- and inter-cycle reproducibility across the tidal breathing range. Mean intra-cycle errors in the position of organ surface landmarks of 1.5(1.4)-3.5(3.3) mm for volunteers and 2.8(1.8)-5.2(5.2) mm for patients. Equivalent measures of inter-cycle variability across this range are 1.7(1.0)-3.9(3.3) mm for volunteers and 2.8(1.8)-3.3(2.2) mm for patients. As expected, models based on breath-hold sequences do not represent normal tidal motion as well as those based on free-breathing data, with mean errors of 4

  17. Measurement of the square measure of the pharynx and the positional diagnosis of airway obstruction during obstructive sleep apnea syndrome by dynamic MRI

    International Nuclear Information System (INIS)

    The purpose of this study was to apply dynamic MRI for the positional diagnosis of airway obstruction during snoring and sleep apnea and to compare the apnea hypopnea index (AHI) and the square measure of the pharynx obtained before and after laser-assisted uvula-palate-pharyngoplasty (LAUP). From December 1997 to October 1998, dynamic MRI and overnight monitoring were performed at the hospital of Tokyo Medical University on 42 patients who complained of snoring and symptoms related to sleep apnea syndrome (SAS). Of the 42 patients, four exhibited collapse at the position of the soft palate (soft palate type) as diagnosed by dynamic MRI, and four exhibited collapse at the position of the soft palate as well as the tongue (complex type). LAUP was performed on these eight patients with obstructive SAS (OSAS). After LAUP, the AHI of these eight patients with OSAS decreased significantly (p<0.05). The square measure of the pharynx of these eight patients was increased (p<0.01). The AHI of all four patients with soft-palate obstruction decreased, and the square measure of the pharynx of three of these four patients increased. The AHI of three of four patients with the complex type decreased, while the square measure of the pharynx of two of these four patients increased. (author)

  18. Measurement of the square measure of the pharynx and the positional diagnosis of airway obstruction during obstructive sleep apnea syndrome by dynamic MRI

    Energy Technology Data Exchange (ETDEWEB)

    Ozuki, Taizo; Ohkubo, Yasuo; Abe, Kimihiko [Tokyo Medical Coll. (Japan)

    2000-11-01

    The purpose of this study was to apply dynamic MRI for the positional diagnosis of airway obstruction during snoring and sleep apnea and to compare the apnea hypopnea index (AHI) and the square measure of the pharynx obtained before and after laser-assisted uvula-palate-pharyngoplasty (LAUP). From December 1997 to October 1998, dynamic MRI and overnight monitoring were performed at the hospital of Tokyo Medical University on 42 patients who complained of snoring and symptoms related to sleep apnea syndrome (SAS). Of the 42 patients, four exhibited collapse at the position of the soft palate (soft palate type) as diagnosed by dynamic MRI, and four exhibited collapse at the position of the soft palate as well as the tongue (complex type). LAUP was performed on these eight patients with obstructive SAS (OSAS). After LAUP, the AHI of these eight patients with OSAS decreased significantly (p<0.05). The square measure of the pharynx of these eight patients was increased (p<0.01). The AHI of all four patients with soft-palate obstruction decreased, and the square measure of the pharynx of three of these four patients increased. The AHI of three of four patients with the complex type decreased, while the square measure of the pharynx of two of these four patients increased. (author)

  19. The value of MRI iniIdiopathic tarsal tunnel syndrome by measuring the cross-sectional area of tarsal tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Jung; Jeong, Yu Mi; Lee, Sheen Woo; Choi Seung; Kim, Jeong Ho; Park, Hong Gi [Gachon University, Gil Hospital, Incheon (Korea, Republic of)

    2015-03-15

    The purpose of this study was to evaluate the use of MRI as a diagnostic test in tarsal tunnel syndrome. There are no published reports with this aim and no diagnostic standard for idiopathic tarsal tunnel syndrome (TTS) using imaging modalities. We retrospectively searched our Picture Archiving and Communication System data and medical records to identify patients who were clinically and electomyographically diagnosed with idiopathic TTS without space-occupying lesion on MRI. Twenty five patients were included in the patient group. Another twenty-five patients who underwent ankle MRI for Achilles tendon disease were selected and included in the control group. Cross-sectional areas (CSA) of tarsal tunnel were manually measured independently by two radiologists who were blinded to clinical and surgical results, using three-dimensional reconstruction software in our hospital. Measurements were done on axial images at three levels (level 1, tibiotalar joint level; level 2, medial malleolar tip level; level 3, sustentaculum tali level). Patient and control group data were statistically analyzed by the Mann-Whitney test. The mean values of CSA at levels 1, 2, and 3 of the tarsal tunnel were 87.8 mm2, 98.2 mm2, and 105.2 mm2, respectively in the patient group; and 100.0 mm2, 113.8 mm2, and 127.9 mm2 in the control group, respectively, in reader 1; and 86.2 mm2, 97.6 mm2, 105.2 mm2, respectively in the patient group; and 99.7 mm2, 112.3 mm2, 124.4 mm2, respectively, in the control group, in reader 2. The mean CSA in the patient group was significantly less than that of the control group at all three levels (p < 0.05). Intra-class correlation coefficient value between reader 1 and reader 2 were 0.98 in group 1, and 0.97 in group 2, respectively. MRI can be helpful in the assessment of idiopathic tarsal tunnel syndrome. CSA measurements of tarsal tunnel at each level may predict TTS even though there are no space occupying lesions in the tarsal tunnel on MRI.

  20. MRI performed on dedicated knee coils is inaccurate for the measurement of tibial tubercle trochlear groove distance

    Energy Technology Data Exchange (ETDEWEB)

    Aarvold, A. [Poole Hospital NHS Foundation Trust, Department of Trauma and Orthopaedic Surgery, Poole, Dorset (United Kingdom); Pope, A. [Royal Bournemouth and Christchurch Hospitals NHS Foundation Trust, Department of Radiology, Bournemouth (United Kingdom); Sakthivel, V.K. [Poole Hospital NHS Foundation Trust, Department of Trauma and Orthopaedic Surgery, Poole, Dorset (United Kingdom); University Hospital Southampton, Department of Paediatric Orthopaedic Surgery, Southampton, Hampshire (United Kingdom); Ayer, R.V. [Poole Hospital NHS Foundation Trust, Department of Radiology, Poole, Dorset (United Kingdom)

    2014-03-15

    Tibial tubercle trochlear groove distance (TTD) is a significant factor in patello-femoral instability. Initially described on CT scans with the knee in full extension, the measurement has been validated on MR scans. Dedicated knee MRI coils have subsequently superseded both CT and MRI body coils for knee imaging. However, the knee rests in partial flexion within the dedicated knee coil. The objective of this study is to investigate whether images from dedicated knee MRI coils produce different TTD measurements from MR body coils. Thirty-two symptomatic knees (27 patients) had simultaneous knee MR scans performed in both a dedicated knee coil and a body coil. TTD measurements were independently compared to assess whether the coil type used affected TTD. Patients' ages ranged from 10 to 27 years (mean 15 years). Mean TTD in the dedicated knee coil (partially flexed knee) was 11.3 mm compared with 19.9 mm in the body coil (that permits full knee extension). The mean difference was 8.6 mm, which was highly significant (p < 0.0001, unpaired t test). Inter-rater correlation co-efficient was 96 %. Of the knees that recorded a ''normal'' TTD on the dedicated knee coil, 60-100 % recorded a ''pathological'' TTD on body coil images, depending on which diagnostic value for ''normal'' cut-off was used. This study has identified a highly significant difference in TTD measurement when knees are scanned in a dedicated knee coil with the knee partially flexed, compared with an MR body coil. It is critical for surgeons and radiologists managing patello-femoral instability to appreciate this profound difference. TTD measurement taken from knees scanned in dedicated knee coils may lead to patients being falsely re-assured or erroneously denied surgery. (orig.)

  1. Lateral diffusion of manganese in the rat brain determined by T1 relaxation time measured by 1H MRI

    International Nuclear Information System (INIS)

    In order to optimize manganese ion-enhanced MRI in thalamic and hypothalamic nuclei, we analyzed the diffusion of manganese in the brain followed by the intra-cerebroventricular application of manganese-bicine (Mn-bicine). T1-weighted MRI intensities, with 9-pixel region of interest (ROI)s in the hypothalamus perpendicular to the third ventricle, were measured during continuous infusion of Mn-bicine solution in the lateral cerebroventricle. Using a relationship between the image intensity of T1-weighted MRI and T1 relaxation time, the image intensity was converted into the concentration of manganese. Assuming a simple diffusion process, the apparent diffusion coefficient (Dap) of manganese (4.2 x 10-5 mm2 s-1) is much lower than that of water (6 x 10-4 mm2 s-1), and the Dap tended to decrease when the distance from the third ventricle increased. These results suggest the Mn2+ ion is trapped by neural cells during diffusion and the manganese efflux is discharged from the brain via veins. (author)

  2. Normal values of the sagittal diameter of the lumbar spine (vertebral body and dural sac) in children measured by MRI

    Energy Technology Data Exchange (ETDEWEB)

    Knirsch, Walter [University Children' s Hospital Freiburg, Department of Pediatric Cardiology, Freiburg (Germany); University Children' s Hospital Zurich, Division of Paediatric Cardiology, Zurich (Switzerland); Kurtz, Claudia; Langer, Mathias [University Hospital Freiburg, Department of Radiology, Freiburg (Germany); Haeffner, Nicole; Kececioglu, Deniz [University Children' s Hospital Freiburg, Department of Pediatric Cardiology, Freiburg (Germany)

    2005-04-01

    The definition of normal values is a prerequisite for the reliable evaluation of abnormality in the lumbar spine, such as spinal canal stenosis or dural ectasia in patients with Marfan syndrome. Values for vertebral body diameter (VBD) and dural sac diameter (DSD) for the lumbar spine have been published in adults. In children, normal values have been established using conventional radiography or myelography, but not by MRI. To define normal values for the sagittal diameter of the vertebral body and dural sac, and to calculate a dural sac ratio (DSR) in the lumbosacral spine (L1-S1) in healthy children using MRI. A total of 75 healthy children between 6 years and 17 years of age were examined using a sagittal T2-weighted sequence. Sagittal VBD and DSD were measured and a DSR was calculated. This was a retrospective and cross-sectional study. With increasing age there is a significant increase of VBD, a slight increase of DSD, and a slight decrease of DSR. There is no significant sex difference. DSR in healthy children is higher than in healthy adults. MRI is a reliable method demonstrating the natural shape of the lumbosacral spine and its absolute values. These normal values compare well with those established by conventional radiological techniques. Our data may serve as a reference for defining dural ectasia in children with Marfan syndrome. (orig.)

  3. Normal values of the sagittal diameter of the lumbar spine (vertebral body and dural sac) in children measured by MRI

    International Nuclear Information System (INIS)

    The definition of normal values is a prerequisite for the reliable evaluation of abnormality in the lumbar spine, such as spinal canal stenosis or dural ectasia in patients with Marfan syndrome. Values for vertebral body diameter (VBD) and dural sac diameter (DSD) for the lumbar spine have been published in adults. In children, normal values have been established using conventional radiography or myelography, but not by MRI. To define normal values for the sagittal diameter of the vertebral body and dural sac, and to calculate a dural sac ratio (DSR) in the lumbosacral spine (L1-S1) in healthy children using MRI. A total of 75 healthy children between 6 years and 17 years of age were examined using a sagittal T2-weighted sequence. Sagittal VBD and DSD were measured and a DSR was calculated. This was a retrospective and cross-sectional study. With increasing age there is a significant increase of VBD, a slight increase of DSD, and a slight decrease of DSR. There is no significant sex difference. DSR in healthy children is higher than in healthy adults. MRI is a reliable method demonstrating the natural shape of the lumbosacral spine and its absolute values. These normal values compare well with those established by conventional radiological techniques. Our data may serve as a reference for defining dural ectasia in children with Marfan syndrome. (orig.)

  4. Peripheral nerve MRI: precision and reproducibility of T2*-derived measurements at 3.0-T. A feasibility study

    International Nuclear Information System (INIS)

    To prospectively evaluate the precision and reproducibility of T2*-derived measurements of the peripheral nerves. The study was approved by the local ethics committee and written informed consent was obtained. Bilateral upper and lower limb MRI examination was performed in 40 healthy subjects on a 3.0-T scanner. MRI protocol included T1-turbo spin-echo, T2-turbo spin-echo with fat suppression, and multiecho gradient recalled echo. Measurements of T2* times on T2* maps at different anatomical levels were performed. Three authors measured independently and in different sessions at baseline and after 4 weeks. Non-parametric tests and Bland-Altman statistics were used. Minimum and maximum percentage variability were 10 % and 19 % for T2* (84-91 % of reproducibility). Maximum values of minimum detectable differences between limbs was 16 % (with 95 % CI: 2-37). Intra- and inter-observer agreement of the three radiologists for T2* was considered good. Evaluating the combined influence of the observer and of the repeated measurements the reproducibility was 87-98 %. T2* measurement of the peripheral nerves is precise and reproducible. The healthy contralateral side can be used as an internal control. Variations in T2* values up to 16 % have to be considered. (orig.)

  5. Peripheral nerve MRI: precision and reproducibility of T2*-derived measurements at 3.0-T. A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Tagliafico, Alberto [University of Genoa, Institute of Anatomy, Department of Experimental Medicine, Genoa (Italy); Bignotti, Bianca; Martinoli, Carlo [University of Genoa, Radiology Department, Genoa, Genova (Italy); Tagliafico, Giulio [CNR-IMATI, Consiglio Nazionale delle Ricerche, Istituto di Matematica Applicata e Tecnologie Informatiche, Genova (Italy)

    2015-05-01

    To prospectively evaluate the precision and reproducibility of T2*-derived measurements of the peripheral nerves. The study was approved by the local ethics committee and written informed consent was obtained. Bilateral upper and lower limb MRI examination was performed in 40 healthy subjects on a 3.0-T scanner. MRI protocol included T1-turbo spin-echo, T2-turbo spin-echo with fat suppression, and multiecho gradient recalled echo. Measurements of T2* times on T2* maps at different anatomical levels were performed. Three authors measured independently and in different sessions at baseline and after 4 weeks. Non-parametric tests and Bland-Altman statistics were used. Minimum and maximum percentage variability were 10 % and 19 % for T2* (84-91 % of reproducibility). Maximum values of minimum detectable differences between limbs was 16 % (with 95 % CI: 2-37). Intra- and inter-observer agreement of the three radiologists for T2* was considered good. Evaluating the combined influence of the observer and of the repeated measurements the reproducibility was 87-98 %. T2* measurement of the peripheral nerves is precise and reproducible. The healthy contralateral side can be used as an internal control. Variations in T2* values up to 16 % have to be considered. (orig.)

  6. Fast Measurement of Intracardiac Pressure Differences With 2D Breath-Hold Phase-Contrast MRI

    OpenAIRE

    Thompson, Richard B; Mcveigh, Elliot R.

    2003-01-01

    Intracardiovascular blood pressure differences can be derived from velocity images acquired with phase-contrast (PC) MRI by evaluating the Navier-Stokes equations. Pressure differences within a slice of interest can be calculated using only the in-plane velocity components from that slice. This rapid exam is proposed as an alternative to the lengthy 3D velocity imaging exams. Despite their good spatial coverage, the 3D exams are prone to artifacts and errors from respiratory motion and insuff...

  7. Chest MRI

    Science.gov (United States)

    Nuclear magnetic resonance - chest; Magnetic resonance imaging - chest; NMR - chest; MRI of the thorax; Thoracic MRI ... healthy enough to filter the contrast. During the MRI, the person who operates the machine will watch ...

  8. The Feasibility of Integrating Elastography Measurements into MRI-Guided Transurethral Ultrasound Therapy

    Science.gov (United States)

    Arani, Arvin; Huang, Yuexi; Bronskill, Michael; Chopra, Rajiv

    2009-04-01

    MRI-guided transurethral ultrasound therapy is being developed as a minimally invasive treatment for localized prostate cancer. The capability to identify target regions prior to therapy would provide an integrated diagnostic and therapeutic solution to the management of this disease. The objective of this project is to evaluate the feasibility of performing elastography using a transurethral actuator. Shear waves were generated in the prostate by vibrating the transurethral actuator longitudinally and resolving the tissue displacements with a 1.5 Tesla MRI. A piezoelectric actuator was used to vibrate the transurethral device with an amplitude of 32 um at frequencies of 100 and 250 Hz. GRE imaging sequences with displacement encoded along the direction of vibration were acquired transverse and parallel to the rod to visualize the dynamics of wave propagation. Experiments were performed in phantoms (8% gelatin) and in a canine model (n = 5). Vibration was achieved in the MRI without significant loss of SNR in the images. The shear waves produced in the gel were cylindrical in nature, and extended along the length of the rod. Shear wave propagation in the canine prostate gland was observed at 100 and 250 Hz, and shear modulus values agreed with previously published values.

  9. Non-invasive liver iron concentration measurement by MRI: Comparison of two validated protocols

    International Nuclear Information System (INIS)

    In the non-invasive determination of the liver iron concentration several validated MRI methods are available, two of which are compared in this study. Twenty-eight patients were examined by MRI and evaluated by the methods of Kreeftenberg et al. [Kreeftenberg Jr HG, Mooyaart EL, Huizenga JR, Sluiter WJ, Kreeftenberg Sr HG. Quantification of liver iron concentration with magnetic resonance imaging by combining T1-, T2-weighted spin echo sequences and a gradient echo sequence. Neth J Med 2000;56:133-7] and Gandon et al. [Gandon Y, Olivie D, Guyader D, et al. Non-invasive assessment of hepatic iron stores by MRI. Lancet 2004;363:357-62]. It is concluded that the latter shows a better inter- and intra-observer correlation and is more accurate because of the automated preselection of one of five sequences most sensitive in the estimated liver iron concentration range. In the Kreeftenberg method combining the results of three suboptimal sequences, leads to underestimation of the liver iron concentration.

  10. Non-invasive liver iron concentration measurement by MRI: Comparison of two validated protocols

    Energy Technology Data Exchange (ETDEWEB)

    Olthof, Allard W. [Department of Radiology, Bethesda Hospital, Dr.G.H. Amshoffweg 1, 7909 AA Hoogeveen (Netherlands)], E-mail: a.w.olthof@hotmail.com; Sijens, Paul E. [Department of Radiology, University Medical Center Groningen and University of Groningen, Hanzeplein 1, 9713 GZ Groningen (Netherlands); Kreeftenberg, Herman G. [Department of Internal Medicine, University Medical Center Groningen and University of Groningen, Hanzeplein 1, 9713 GZ Groningen (Netherlands); Kappert, Peter; Jagt, Eric J. van der; Oudkerk, Matthijs [Department of Radiology, University Medical Center Groningen and University of Groningen, Hanzeplein 1, 9713 GZ Groningen (Netherlands)

    2009-07-15

    In the non-invasive determination of the liver iron concentration several validated MRI methods are available, two of which are compared in this study. Twenty-eight patients were examined by MRI and evaluated by the methods of Kreeftenberg et al. [Kreeftenberg Jr HG, Mooyaart EL, Huizenga JR, Sluiter WJ, Kreeftenberg Sr HG. Quantification of liver iron concentration with magnetic resonance imaging by combining T1-, T2-weighted spin echo sequences and a gradient echo sequence. Neth J Med 2000;56:133-7] and Gandon et al. [Gandon Y, Olivie D, Guyader D, et al. Non-invasive assessment of hepatic iron stores by MRI. Lancet 2004;363:357-62]. It is concluded that the latter shows a better inter- and intra-observer correlation and is more accurate because of the automated preselection of one of five sequences most sensitive in the estimated liver iron concentration range. In the Kreeftenberg method combining the results of three suboptimal sequences, leads to underestimation of the liver iron concentration.

  11. Quantitative cartilage volume measurement using MRI: comparison of different evaluation techniques

    International Nuclear Information System (INIS)

    This study was aimed to investigate the accuracy and time saving of MRI Argus application in the assessment of cartilage volume in osteoarthritic knees. Twelve knees of patients suffering from osteoarthritis were scanned with a 1.5 T MRI using a 3D gradient echo sequence with selective water excitation. Cartilage volume of the tibial and patellar compartment was determined with a validated multiprocessing computer system (Octane Duo, Silicon Graphics, Mountain View, Calif., USA). The calculated cartilage volumes were compared to the results acquired by the Argus (Siemens Inc., Erlangen, Germany) application software using the MRI data sets. Compared to the multiprocessing computer system a time saving of at least 30 min for cartilage volume determination was achieved. The mean differences of Argus versus the multiprocessing computer system were 4.26±0.84 and 7.80±0.87% for the medial and lateral tibial plateau and 5.94±0.59% for the patella (no statistical significant difference; P>0.05). The applied Argus software can be used for fast and accurate determination of cartilage volume in the knee joint. (orig.)

  12. Quantitative cartilage volume measurement using MRI: comparison of different evaluation techniques.

    Science.gov (United States)

    Maataoui, Adel; Graichen, Heiko; Abolmaali, Nasreddin D; Khan, Mohammad F; Gurung, Jessen; Straub, Ralf; Qian, Jun; Hinterwimmer, Stefan; Ackermann, Hanns; Vogl, Thomas J

    2005-08-01

    This study was aimed to investigate the accuracy and time saving of MRI Argus application in the assessment of cartilage volume in osteoarthritic knees. Twelve knees of patients suffering from osteoarthritis were scanned with a 1.5 T MRI using a 3D gradient echo sequence with selective water excitation. Cartilage volume of the tibial and patellar compartment was determined with a validated multiprocessing computer system (Octane Duo, Silicon Graphics, Mountain View, Calif., USA). The calculated cartilage volumes were compared to the results acquired by the Argus (Siemens Inc., Erlangen, Germany) application software using the MRI data sets. Compared to the multiprocessing computer system a time saving of at least 30 min for cartilage volume determination was achieved. The mean differences of Argus versus the multiprocessing computer system were 4.26+/-0.84 and 7.80+/-0.87% for the medial and lateral tibial plateau and 5.94+/-0.59% for the patella (no statistical significant difference; P>0.05). The applied Argus software can be used for fast and accurate determination of cartilage volume in the knee joint. PMID:15856246

  13. MRI-based measurements of respiratory motion variability and assessment of imaging strategies for radiotherapy planning

    Energy Technology Data Exchange (ETDEWEB)

    Blackall, J M [Centre for Medical Image Computing, University College London, WC1E 6BT (United Kingdom); Ahmad, S [Department of Radiotherapy, Guy' s and St. Thomas' Trust, London, SE1 7EH (United Kingdom); Miquel, M E [Division of Imaging Sciences, GKT Schools of Medicine, London, SE1 9RT (United Kingdom); McClelland, J R [Centre for Medical Image Computing, University College London, WC1E 6BT (United Kingdom); Landau, D B [Department of Radiotherapy, Guy' s and St. Thomas' Trust, London, SE1 7EH (United Kingdom); Hawkes, D J [Centre for Medical Image Computing, University College London, WC1E 6BT (United Kingdom)

    2006-09-07

    Respiratory organ motion has a significant impact on the planning and delivery of radiotherapy (RT) treatment for lung cancer. Currently widespread techniques, such as 4D-computed tomography (4DCT), cannot be used to measure variability of this motion from one cycle to the next. In this paper, we describe the use of fast magnetic resonance imaging (MRI) techniques to investigate the intra- and inter-cycle reproducibility of respiratory motion and also to estimate the level of errors that may be introduced into treatment delivery by using various breath-hold imaging strategies during lung RT planning. A reference model of respiratory motion is formed to enable comparison of different breathing cycles at any arbitrary position in the respiratory cycle. This is constructed by using free-breathing images from the inhale phase of a single breathing cycle, then co-registering the images, and thereby tracking landmarks. This reference model is then compared to alternative models constructed from images acquired during the exhale phase of the same cycle and the inhale phase of a subsequent cycle, to assess intra- and inter-cycle variability ('hysteresis' and 'reproducibility') of organ motion. The reference model is also compared to a series of models formed from breath-hold data at exhale and inhale. Evaluation of these models is carried out on data from ten healthy volunteers and five lung cancer patients. Free-breathing models show good levels of intra- and inter-cycle reproducibility across the tidal breathing range. Mean intra-cycle errors in the position of organ surface landmarks of 1.5(1.4)-3.5(3.3) mm for volunteers and 2.8(1.8)-5.2(5.2) mm for patients. Equivalent measures of inter-cycle variability across this range are 1.7(1.0)-3.9(3.3) mm for volunteers and 2.8(1.8)-3.3(2.2) mm for patients. As expected, models based on breath-hold sequences do not represent normal tidal motion as well as those based on free-breathing data, with mean errors

  14. MRI characterization of temporal lobe epilepsy using rapidly measurable spatial indices with hemisphere asymmetries and gender features

    International Nuclear Information System (INIS)

    The paucity of morphometric markers for hemispheric asymmetries and gender variations in hippocampi and amygdalae in temporal lobe epilepsy (TLE) calls for better characterization of TLE by finding more useful prognostic MRI parameter(s). T1-weighted MRI (3 T) morphometry using multiple parameters of hippocampus-parahippocampus (angular and linear measures, volumetry) and amygdalae (volumetry) including their hemispheric asymmetry indices (AI) were evaluated in both genders. The cutoff values of parameters were statistically estimated from measurements of healthy subjects to characterize TLE (57 patients, 55 % male) alterations. TLE had differential categories with hippocampal atrophy, parahippocampal angle (PHA) acuteness, and several other parametric changes. Bilateral TLE categories were much more prevalent compared to unilateral TLE categories. Female patients were considerably more disposed to bilateral TLE categories than male patients. Male patients displayed diverse categories of unilateral abnormalities. Few patients (both genders) had combined bilateral appearances of hippocampal atrophy, amygdala atrophy, PHA acuteness, and increase in hippocampal angle (HA) where medial distance ratio (MDR) varied among genders. TLE had gender-specific and hemispheric dominant alterations in AI of parameters. Maximum magnitude of parametric changes in TLE includes (a) AI increase in HA of both genders, (b) HA increase (bilateral) in female patients, and (c) increase in ratio of amygdale/hippocampal volume (unilateral, right hemispheric), and AI decrease in MDR, in male patients. Multiparametric MRI studies of hippocampus and amygdalae, including their hemispheric asymmetry, underscore better characterization of TLE. Rapidly measurable single-slice parameters (HA, PHA, MDR) can readily delineate TLE in a time-constrained clinical setting, which contrasts with customary three-dimensional hippocampal volumetry that requires many slice computation. (orig.)

  15. MRI characterization of temporal lobe epilepsy using rapidly measurable spatial indices with hemisphere asymmetries and gender features

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Siddhartha; Chakrabarti, Nilkanta [University of Calcutta, Department of Physiology and UGC-CPEPA Centre for ' ' Electro-physiological and Neuro-imaging studies including Mathematical Modelling' ' , Kolkata (India); Sarkar, Sudipta; Chakraborty, Sumit; Basu, Swadhapriya [IPGME and R, SSKM Hospital, Department of Radiodiagnosis, Kolkata (India); Mulpuru, Sai Krishna [National Brain Research Centre, National Neuro-Imaging Facility, Manesar (India); Tiwary, Basant K. [Pondicherry University, Centre for Bioinformatics, School of Life Sciences, Pondicherry (India); Roy, Prasun Kumar [National Brain Research Centre, Computational Neuroimaging Division, Manesar (India); National Brain Research Centre, Clinical Neuroscience Unit, Gurgaon (India)

    2015-09-15

    The paucity of morphometric markers for hemispheric asymmetries and gender variations in hippocampi and amygdalae in temporal lobe epilepsy (TLE) calls for better characterization of TLE by finding more useful prognostic MRI parameter(s). T1-weighted MRI (3 T) morphometry using multiple parameters of hippocampus-parahippocampus (angular and linear measures, volumetry) and amygdalae (volumetry) including their hemispheric asymmetry indices (AI) were evaluated in both genders. The cutoff values of parameters were statistically estimated from measurements of healthy subjects to characterize TLE (57 patients, 55 % male) alterations. TLE had differential categories with hippocampal atrophy, parahippocampal angle (PHA) acuteness, and several other parametric changes. Bilateral TLE categories were much more prevalent compared to unilateral TLE categories. Female patients were considerably more disposed to bilateral TLE categories than male patients. Male patients displayed diverse categories of unilateral abnormalities. Few patients (both genders) had combined bilateral appearances of hippocampal atrophy, amygdala atrophy, PHA acuteness, and increase in hippocampal angle (HA) where medial distance ratio (MDR) varied among genders. TLE had gender-specific and hemispheric dominant alterations in AI of parameters. Maximum magnitude of parametric changes in TLE includes (a) AI increase in HA of both genders, (b) HA increase (bilateral) in female patients, and (c) increase in ratio of amygdale/hippocampal volume (unilateral, right hemispheric), and AI decrease in MDR, in male patients. Multiparametric MRI studies of hippocampus and amygdalae, including their hemispheric asymmetry, underscore better characterization of TLE. Rapidly measurable single-slice parameters (HA, PHA, MDR) can readily delineate TLE in a time-constrained clinical setting, which contrasts with customary three-dimensional hippocampal volumetry that requires many slice computation. (orig.)

  16. MRI and low back pain

    Science.gov (United States)

    Backache - MRI; Low back pain - MRI; Lumbar pain - MRI; Back strain - MRI; Lumbar radiculopathy - MRI; Herniated intervertebral disk - MRI; Prolapsed intervertebral disk - MRI; Slipped disk - MRI; Ruptured ...

  17. Classification of First-Episode Schizophrenia Patients and Healthy Subjects by Automated MRI Measures of Regional Brain Volume and Cortical Thickness

    OpenAIRE

    Yoichiro Takayanagi; Tsutomu Takahashi; Lina Orikabe; Yuriko Mozue; Yasuhiro Kawasaki; Kazue Nakamura; Yoko Sato; Masanari Itokawa; Hidenori Yamasue; Kiyoto Kasai; Masayoshi Kurachi; Yuji Okazaki; Michio Suzuki

    2011-01-01

    BACKGROUND: Although structural magnetic resonance imaging (MRI) studies have repeatedly demonstrated regional brain structural abnormalities in patients with schizophrenia, relatively few MRI-based studies have attempted to distinguish between patients with first-episode schizophrenia and healthy controls. METHOD: Three-dimensional MR images were acquired from 52 (29 males, 23 females) first-episode schizophrenia patients and 40 (22 males, 18 females) healthy subjects. Multiple brain measure...

  18. Variability in MRI vs. ultrasound measures of prostate volume and its impact on treatment recommendations for favorable-risk prostate cancer patients: a case series

    International Nuclear Information System (INIS)

    Prostate volume can affect whether patients qualify for brachytherapy (desired size ≥20 mL and ≤60 mL) and/or active surveillance (desired PSA density ≤0.15 for very low risk disease). This study examines variability in prostate volume measurements depending on imaging modality used (ultrasound versus MRI) and volume calculation technique (contouring versus ellipsoid) and quantifies the impact of this variability on treatment recommendations for men with favorable-risk prostate cancer. We examined 70 patients who presented consecutively for consideration of brachytherapy for favorable-risk prostate cancer who had volume estimates by three methods: contoured axial ultrasound slices, ultrasound ellipsoid (height × width × length × 0.523) calculation, and endorectal coil MRI (erMRI) ellipsoid calculation. Average gland size by the contoured ultrasound, ellipsoid ultrasound, and erMRI methods were 33.99, 37.16, and 39.62 mLs, respectively. All pairwise comparisons between methods were statistically significant (all p < 0.015). Of the 66 patients who volumetrically qualified for brachytherapy on ellipsoid ultrasound measures, 22 (33.33%) did not qualify on ellipsoid erMRI or contoured ultrasound measures. 38 patients (54.28%) had PSA density ≤0.15 ng/dl as calculated using ellipsoid ultrasound volumes, compared to 34 (48.57%) and 38 patients (54.28%) using contoured ultrasound and ellipsoid erMRI volumes, respectively. The ultrasound ellipsoid and erMRI ellipsoid methods appeared to overestimate ultrasound contoured volume by an average of 9.34% and 16.57% respectively. 33.33% of those who qualified for brachytherapy based on ellipsoid ultrasound volume would be disqualified based on ultrasound contoured and/or erMRI ellipsoid volume. As treatment recommendations increasingly rely on estimates of prostate size, clinicians must consider method of volume estimation

  19. Global Functional Connectivity Differences between Sleep-Like States in Urethane Anesthetized Rats Measured by fMRI

    Science.gov (United States)

    Paasonen, Jaakko; Shatillo, Artem; Lipponen, Arto; Salo, Raimo; Aliev, Rubin; Tanila, Heikki; Gröhn, Olli

    2016-01-01

    Sleep is essential for nervous system functioning and sleep disorders are associated with several neurodegenerative diseases. However, the macroscale connectivity changes in brain networking during different sleep states are poorly understood. One of the hindering factors is the difficulty to combine functional connectivity investigation methods with spontaneously sleeping animals, which prevents the use of numerous preclinical animal models. Recent studies, however, have implicated that urethane anesthesia can uniquely induce different sleep-like brain states, resembling rapid eye movement (REM) and non-REM (NREM) sleep, in rodents. Therefore, the aim of this study was to assess changes in global connectivity and topology between sleep-like states in urethane anesthetized rats, using blood oxygenation level dependent (BOLD) functional magnetic resonance imaging. We detected significant changes in corticocortical (increased in NREM-like state) and corticothalamic connectivity (increased in REM-like state). Additionally, in graph analysis the modularity, the measure of functional integration in the brain, was higher in NREM-like state than in REM-like state, indicating a decrease in arousal level, as in normal sleep. The fMRI findings were supported by the supplementary electrophysiological measurements. Taken together, our results show that macroscale functional connectivity changes between sleep states can be detected robustly with resting-state fMRI in urethane anesthetized rats. Our findings pave the way for studies in animal models of neurodegenerative diseases where sleep abnormalities are often one of the first markers for the disorder development. PMID:27168145

  20. Global Functional Connectivity Differences between Sleep-Like States in Urethane Anesthetized Rats Measured by fMRI.

    Directory of Open Access Journals (Sweden)

    Ekaterina Zhurakovskaya

    Full Text Available Sleep is essential for nervous system functioning and sleep disorders are associated with several neurodegenerative diseases. However, the macroscale connectivity changes in brain networking during different sleep states are poorly understood. One of the hindering factors is the difficulty to combine functional connectivity investigation methods with spontaneously sleeping animals, which prevents the use of numerous preclinical animal models. Recent studies, however, have implicated that urethane anesthesia can uniquely induce different sleep-like brain states, resembling rapid eye movement (REM and non-REM (NREM sleep, in rodents. Therefore, the aim of this study was to assess changes in global connectivity and topology between sleep-like states in urethane anesthetized rats, using blood oxygenation level dependent (BOLD functional magnetic resonance imaging. We detected significant changes in corticocortical (increased in NREM-like state and corticothalamic connectivity (increased in REM-like state. Additionally, in graph analysis the modularity, the measure of functional integration in the brain, was higher in NREM-like state than in REM-like state, indicating a decrease in arousal level, as in normal sleep. The fMRI findings were supported by the supplementary electrophysiological measurements. Taken together, our results show that macroscale functional connectivity changes between sleep states can be detected robustly with resting-state fMRI in urethane anesthetized rats. Our findings pave the way for studies in animal models of neurodegenerative diseases where sleep abnormalities are often one of the first markers for the disorder development.

  1. Correlation of intra-articular osseous measurements with posterior cruciate ligament length on MRI scans.

    LENUS (Irish Health Repository)

    Orakzai, S H

    2010-01-01

    Six patients with a clinical diagnosis of chronic posterior cruciate ligament (PCL) rupture, based on a positive posterior drawer test, had a normal appearance of the PCL on an MRI scan. It is postulated that the PCL had been ruptured but healed in a lengthened state. 12 volunteers with no history of knee trauma underwent an MRI scan of the knee. In this control group (n = 12), there was a close correlation between the lateral femoral condylar width in the sagittal plane and the PCL length, with a ratio of 2:1 (95% confidence interval (CI) = 1.817-2.095). In the clinically abnormal group (n = 6), the ratio was 1.49:1 (95% CI = 1.206-1.782) (p< 0.0005). In conclusion, the ratio of the lateral femoral condylar width in the sagittal plane to the PCL length is a useful index for diagnosing PCL attenuation and lengthening in the presence of a normal morphological MR appearance.

  2. Correlation between Heart and Liver Iron Levels Measured by MRI T2* and Serum Ferritin in Patients with β-thalassemia Major

    Directory of Open Access Journals (Sweden)

    Razieh Taghizadeh Sarvestani

    2016-03-01

    Full Text Available Background Transfusion-induced iron overload leads to many complications in patients with β-thalassemia major. This study aimed to compare the level of iron stored in the liver and heart measured by MRI T2 * with ferritin levels in these patients. Materials and Methods This study was done on 52 patients with β-thalassemia major aged 7 to 29 years. Serum ferritin level was checked and heart and liver MRI T2* operation was performed, then the liver and heart iron level measured by MRI T2 * was compared with serum ferritin levels. Results 150-180 cc/kg packed cells were received on average. The mean ± SD serum ferritin level was 2644.8±1988.3 ng/mL. The mean ± SD relaxation times in liver and heart MRI T2* were 4.39±5.8 and 26.59±10.62 millisecond, respectively. A negative significant correlation was found between serum ferritin levels and liver MRI T2* (P0.05. Conclusion Since there was no correlation between serum ferritin levels and cardiac iron levels, accurate assessment of cardiac iron load using MRI T2* is necessary in patients with β-thalassemia major. Serum ferritin level is reliable for assessing liver iron levels.

  3. Concordance of Epileptic Networks Associated with Epileptic Spikes Measured by High-Density EEG and Fast fMRI.

    Directory of Open Access Journals (Sweden)

    Vera Jäger

    Full Text Available The present study aims to investigate whether a newly developed fast fMRI called MREG (magnetic resonance encephalography measures metabolic changes related to interictal epileptic discharges (IED. For this purpose BOLD changes are correlated with the IED distribution and variability.Patients with focal epilepsy underwent EEG-MREG using a 64 channel cap. IED voltage maps were generated using 32 and 64 channels and compared regarding their correspondence to the BOLD response. The extents of IEDs (defined as number of channels with >50% of maximum IED negativity were correlated with the extents of positive and negative BOLD responses. Differences in inter-spike variability were investigated between interictal epileptic discharges (IED sets with and without concordant positive or negative BOLD responses.17 patients showed 32 separate IED types. In 50% of IED types the BOLD changes could be confirmed by another independent imaging method. The IED extent significantly correlated with the positive BOLD extent (p = 0.04. In 6 patients the 64-channel EEG voltage maps better reflected the positive or negative BOLD response than the 32-channel EEG; in all others no difference was seen. Inter-spike variability was significantly lower in IED sets with than without concordant positive or negative BOLD responses (with p = 0.04.Higher density EEG and fast fMRI seem to improve the value of EEG-fMRI in epilepsy. The correlation of positive BOLD and IED extent could suggest that widespread BOLD responses reflect the IED network. Inter-spike variability influences the likelihood to find IED concordant positive or negative BOLD responses, which is why single IED analysis may be promising.

  4. Right-sided cardiac function in healthy volunteers measured by first-pass radionuclide ventriculography and gated blood-pool SPECT: comparison with cine MRI

    DEFF Research Database (Denmark)

    Kjaer, Andreas; Lebech, Anne-Mette; Hesse, Birger;

    2005-01-01

    evaluation of right-sided cardiac function. The aim of our study was to compare the agreement between these methods when measuring right-sided cardiac function. METHODS: Twenty-four healthy volunteers were included. Mean age was 44 years (range: 25-60) and 29% were females. All participants had FP, GBPS and...... 6 ml m(-2) (95% CI: 0-11). CONCLUSIONS: (i) Normal values of RVEF differ between MRI, FP and GBPS with wide limits of agreement, accordingly it is difficult to evaluate changes over time if measured by different methods, (ii) RV volumes are in the same range when measured by MRI or GBPS but with...... wide limits of agreement, and (iii) if MRI is considered gold standard then FP is more accurate than GBPS for RVEF measurements....

  5. Relationship between saccadic eye movements and cortical activity as measured by fMRI

    DEFF Research Database (Denmark)

    Kimmig, H.; Greenlee, M.W.; Gondan, Matthias;

    2001-01-01

    quantitative changes in cortical activity associated with qualitative changes in the saccade task for comparable levels of saccadic activity. All experiments required the simultaneous acquisition of eye movement and fMRI data. For this purpose we used a new high-resolution limbus-tracking technique...... for recording eye movements in the magnetic resonance tomograph. In the first two experimental series we varied both frequency and amplitude of saccade stimuli (target jumps). In the third series we varied task difficulty; subjects performed either pro-saccades or anti-saccades. The brain volume investigated...... comprised the frontal and supplementary eye fields, parietal as well as striate cortex, and the motion sensitive area of the parieto-occipital cortex. All these regions showed saccade-related BOLD responses. The responses in these regions were highly correlated with saccade frequency, indicating...

  6. Three-dimensional thickness and volume measurements of knee joint cartilage with MRI. Validation in anatomical specimens via CT arthrography

    International Nuclear Information System (INIS)

    Purpose: In the present study we intended to validate knee joint cartilage volume and thickness measurements with MRI. Methods: Ten fresh cadaver knees (age 29 to 64 yrs.) were sagitally imaged, using a fat-suppressed FLASH-3D sequence with a resolution of 2x0,31x0,31 mm3. Then a contrast agent was injected and the specimens submitted to CT arthrography. From both modalities the patellar, femoral, and tibial cartilages were segmented semiautomatically and reconstructed three-dimensionally. The cartilage thickness was determined independently of the sectional plane, based on a 'minimal distance algorithm'. Results: The volumes and the regional distribution patterns yielded a very high degree of similarity on direct comparison of both imaging modalities. The average volume error between MRI and CT was 3.8% (±3.0%), the correlation 0.998, the slope of the regression line 1.04 and the y-intercept -80 mm3. The analysis yielded no significant differences between the two methods (Wilcoxon signed rank test, 5% level) in the patella, femur, medial, and lateral tibia. (orig.)

  7. SU-D-303-03: Impact of Uncertainty in T1 Measurements On Quantification of Dynamic Contrast Enhanced MRI

    Energy Technology Data Exchange (ETDEWEB)

    Aryal, M; Cao, Y [The University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: Quantification of dynamic contrast enhanced (DCE) MRI requires native longitudinal relaxation time (T1) measurement. This study aimed to assess uncertainty in T1 measurements using two different methods. Methods and Materials: Brain MRI scans were performed on a 3T scanner in 9 patients who had low grade/benign tumors and partial brain radiotherapy without chemotherapy at pre-RT, week-3 during RT (wk-3), end-RT, and 1, 6 and 18 months after RT. T1-weighted images were acquired using gradient echo sequences with 1) 2 different flip angles (50 and 150), and 2) 5 variable TRs (100–2000ms). After creating quantitative T1 maps, average T1 was calculated in regions of interest (ROI), which were distant from tumors and received a total of accumulated radiation doses < 5 Gy at wk-3. ROIs included left and right normal Putamen and Thalamus (gray matter: GM), and frontal and parietal white matter (WM). Since there were no significant or even a trend of T1 changes from pre-RT to wk-3 in these ROIs, a relative repeatability coefficient (RC) of T1 as a measure of uncertainty was estimated in each ROI using the data pre-RT and at wk-3. The individual T1 changes at later time points were evaluated compared to the estimated RCs. Results: The 2-flip angle method produced small RCs in GM (9.7–11.7%) but large RCs in WM (12.2–13.6%) compared to the saturation-recovery (SR) method (11.0–17.7% for GM and 7.5–11.2% for WM). More than 81% of individual T1 changes were within T1 uncertainty ranges defined by RCs. Conclusion: Our study suggests that the impact of T1 uncertainty on physiological parameters derived from DCE MRI is not negligible. A short scan with 2 flip angles is able to achieve repeatability of T1 estimates similar to a long scan with 5 different TRs, and is desirable to be integrated in the DCE protocol. Present study was supported by National Institute of Health (NIH) under grant numbers; UO1 CA183848 and RO1 NS064973.

  8. SU-D-303-03: Impact of Uncertainty in T1 Measurements On Quantification of Dynamic Contrast Enhanced MRI

    International Nuclear Information System (INIS)

    Purpose: Quantification of dynamic contrast enhanced (DCE) MRI requires native longitudinal relaxation time (T1) measurement. This study aimed to assess uncertainty in T1 measurements using two different methods. Methods and Materials: Brain MRI scans were performed on a 3T scanner in 9 patients who had low grade/benign tumors and partial brain radiotherapy without chemotherapy at pre-RT, week-3 during RT (wk-3), end-RT, and 1, 6 and 18 months after RT. T1-weighted images were acquired using gradient echo sequences with 1) 2 different flip angles (50 and 150), and 2) 5 variable TRs (100–2000ms). After creating quantitative T1 maps, average T1 was calculated in regions of interest (ROI), which were distant from tumors and received a total of accumulated radiation doses < 5 Gy at wk-3. ROIs included left and right normal Putamen and Thalamus (gray matter: GM), and frontal and parietal white matter (WM). Since there were no significant or even a trend of T1 changes from pre-RT to wk-3 in these ROIs, a relative repeatability coefficient (RC) of T1 as a measure of uncertainty was estimated in each ROI using the data pre-RT and at wk-3. The individual T1 changes at later time points were evaluated compared to the estimated RCs. Results: The 2-flip angle method produced small RCs in GM (9.7–11.7%) but large RCs in WM (12.2–13.6%) compared to the saturation-recovery (SR) method (11.0–17.7% for GM and 7.5–11.2% for WM). More than 81% of individual T1 changes were within T1 uncertainty ranges defined by RCs. Conclusion: Our study suggests that the impact of T1 uncertainty on physiological parameters derived from DCE MRI is not negligible. A short scan with 2 flip angles is able to achieve repeatability of T1 estimates similar to a long scan with 5 different TRs, and is desirable to be integrated in the DCE protocol. Present study was supported by National Institute of Health (NIH) under grant numbers; UO1 CA183848 and RO1 NS064973

  9. MRI-based flow measurements in the main pulmonary artery to detect pulmonary arterial hypertension in patients with cystic fibrosis

    International Nuclear Information System (INIS)

    Development of pulmonary arterial hypertension (PH) is a common problem in the course of patients suffering from cystic fibrosis (CF). This study was performed to evaluate MRI based flow measurements (MRvenc; Velocity ENCoding) to detect signs of an evolving PH in patients suffering from CF. 48 patients (median age: 16 years, range: 10 - 40 years, 25 female) suffering from CF of different severity (mean FEV1: 74 % ± 23, mean Shwachman-score: 63 ± 10) were examined using MRI based flow measurements of the main pulmonary artery (MPA). Phase-contrast flash sequences (TR: 9.6 ms, TE: 2.5 ms, bandwidth: 1395 Hertz/Pixel) were utilized. Results were compared to an age- and sex-matched group of 48 healthy subjects. Analyzed flow data where: heart frequency (HF), cardiac output (HZV), acceleration time (AT), proportional acceleration time related to heart rate (ATr), mean systolic blood velocity (MFG), peak velocity (Peak), maximum flow (Flussmax), mean flow (Flussmitt) and distensibility (Dist). The comparison of means revealed significant differences only for MFG, Flussmax and Dist, but overlap was marked. However, using a scatter-plot of AT versus MFG, it was possible to identify five CF-patients demonstrating definite signs of PH: AT = 81 ms ± 14, MFG = 46 ± 11 cm/s, Dist = 41 % ± 7. These CF-patients where the most severely affected in the investigated group, two of them were listed for complete heart and lung transplantation. The comparison of this subgroup and the remaining CF-patients revealed a highly significant difference for the AT (p = 0.000001) without overlap. Screening of CF-patients for the development of PH using MRvenc of the MPA is not possible. In later stages of disease, the quantification of AT, MFG and Dist in the MPA may be useful for the detection, follow-up and control of therapy of PH. MRvenc of the MPA completes the MRI-based follow-up of lung parenchyma damage in patients suffering from CF. (orig.)

  10. Is the type and extent of hippocampal sclerosis measurable on high-resolution MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Urbach, H; Schwarzwald, R [Medical Center University of Freiburg, Dept. of Neuroradiology, Freiburg (Germany); Huppertz, H.J. [Swiss Epilepsy Center, Zurich (Switzerland); Becker, A.J. [Medical Center University of Bonn, Department of Neuropathology, Bonn (Germany); Wagner, J. [Medical Center University of Bonn, Department of Epileptology, Bonn (Germany); Bahri, M. Delsous; Tschampa, H.J. [Medical Center University of Bonn, Department of Radiology/Neuroradiology, Bonn (Germany)

    2014-09-15

    The purpose of this study is to relate hippocampal volume and FLAIR signal intensity to Wyler grading of hippocampal sclerosis (HS). Of 100 consecutive patients with temporal lobe epilepsy and HS as histopathological diagnosis, 32 had high-resolution 3 Tesla MRI and anatomically well-preserved hippocampi following amygdalo-hippocampectomy. Hippocampal volume on 3D T1-weighted gradient echo and signal intensity on coronal FLAIR sequences were determined using FreeSurfer and SPM tools and related to Wyler grading. Seizure outcome was determined after 1 year. Histopathology showed four Wyler II, 19 Wyler III, and 9 Wyler IV HS. Hippocampal volumes were 3.08 ml for Wyler II (Wyler II/contralateral side: p > 0.05), 2.19 ml for Wyler III (p < 0.01), 2.62 ml for Wyler IV (p = 0.01), and 3.08 ml for the contralateral side. Normalized FLAIR signals were 1,354 (p = 0.0004), 1,408 (p < 0.0001), 1,371 (p < 0.04), and 1,296, respectively. Wyler II hippocampi were visually normal. Two of four (50 %) Wyler II, 16/19 (84 %) Wyler III, and 6/9 (66 %) Wyler IV patients achieved Engel I outcome. Combined volumetry and quantitative FLAIR signal analysis clearly identifies Wyler III and IV HS. Quantitative FLAIR signal analysis may be helpful to identify Wyler II HS. (orig.)

  11. Is the type and extent of hippocampal sclerosis measurable on high-resolution MRI?

    International Nuclear Information System (INIS)

    The purpose of this study is to relate hippocampal volume and FLAIR signal intensity to Wyler grading of hippocampal sclerosis (HS). Of 100 consecutive patients with temporal lobe epilepsy and HS as histopathological diagnosis, 32 had high-resolution 3 Tesla MRI and anatomically well-preserved hippocampi following amygdalo-hippocampectomy. Hippocampal volume on 3D T1-weighted gradient echo and signal intensity on coronal FLAIR sequences were determined using FreeSurfer and SPM tools and related to Wyler grading. Seizure outcome was determined after 1 year. Histopathology showed four Wyler II, 19 Wyler III, and 9 Wyler IV HS. Hippocampal volumes were 3.08 ml for Wyler II (Wyler II/contralateral side: p > 0.05), 2.19 ml for Wyler III (p < 0.01), 2.62 ml for Wyler IV (p = 0.01), and 3.08 ml for the contralateral side. Normalized FLAIR signals were 1,354 (p = 0.0004), 1,408 (p < 0.0001), 1,371 (p < 0.04), and 1,296, respectively. Wyler II hippocampi were visually normal. Two of four (50 %) Wyler II, 16/19 (84 %) Wyler III, and 6/9 (66 %) Wyler IV patients achieved Engel I outcome. Combined volumetry and quantitative FLAIR signal analysis clearly identifies Wyler III and IV HS. Quantitative FLAIR signal analysis may be helpful to identify Wyler II HS. (orig.)

  12. Dose distribution measurements by MRI of a phantom containing lung tissue equivalent compartments made of ferrous sulphate gel

    International Nuclear Information System (INIS)

    Gel dosimetry based on magnetic resonance imaging (MRI) has previously been shown to provide verification of calculated dose distributions in soft tissue equivalent homogeneous phantoms. This study demonstrates how measurements of dose distribution can also be achieved in a phantom containing porous, lung-equivalent, Fricke gel. A phantom was made of Fe2+-infused low-density gel and conventional ferrous sulphate gel, filled in separate compartments in a Perspex container. Absorbed dose measurements were accomplished by MR imaging and by calibrating the proton spin-lattice relaxation rate (R1) versus absorbed dose by means of TLD measurements. This study shows that the production of lung-equivalent low-density (LD) dosimeter gel (mean CT number of -610 HU) is feasible. The MR signal detected in the LD gel dosimeter was substantially more noisy (i.e. displayed larger random fluctuations) than the signal from conventional gel, as expected. A deviation between calculated (TPS) and measured dose of about 3% (6 MV) and 4-7% (15 MV) was found in the LD region of the phantom. These results correspond well with data from other studies of dose distribution in lung-equivalent phantoms. The Fe2+-infused LD gel therefore seems suitable for measurement of absorbed dose distribution in phantoms that contain lung tissue compartments. (author)

  13. MRI Scans

    Science.gov (United States)

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from ...

  14. Virtual milgram: empathic concern or personal distress? Evidence from functional MRI and dispositional measures

    Directory of Open Access Journals (Sweden)

    Marcus Cheetham

    2009-10-01

    Full Text Available One motive for behaving as the agent of another’s aggression appears to be anchored in as yet unelucidated mechanisms of obedience to authority. In a recent partial replication of Milgram’s obedience paradigm within an immersive virtual environment, participants administered pain to a female virtual human and observed her suffering. Whether the participants’ response to the latter was more akin to other-oriented empathic concern for her well-being or to a self-oriented aversive state of personal distress in response to her distress is unclear. Using the stimuli from the previous study, this event-related fMRI-based study analysed brain activity during observation of the victim in pain compared with no pain. This contrast revealed activation in pre-defined brain areas known to be involved in affective processing, but not those commonly associated with affect sharing (e.g. ACC and insula. We then examined whether different dimensions of dispositional empathy predict activity within the same pre-defined brain regions: While personal distress and fantasy (i.e. tendency to transpose oneself in fictional situations and characters predicted brain activity, empathic concern and perspective taking predicted no change in neuronal response associated with pain observation. These exploratory findings suggest that there is a distinct pattern of brain activity associated with observing the pain-related behaviour of the victim within the context of this social dilemma, that this observation evoked a self-oriented aversive state of personal distress, that the objective ‘reality’ of pain is of secondary importance for this response. These findings provide a starting point for an experimentally more rigorous approach to the investigation of obedience.

  15. Differentiating SCT and inattentive symptoms in ADHD using fMRI measures of cognitive control

    Directory of Open Access Journals (Sweden)

    Catherine Fassbender

    2015-01-01

    Full Text Available Attention Deficit/Hyperactivity Disorder (ADHD is associated with different impairment profiles in the symptom domains of hyperactivity/impulsivity and/or inattention. An additional symptom domain of sluggish cognitive tempo (SCT has also been proposed. Although there is a degree of correlation between the SCT symptom domain and inattention, it has been proposed as a distinct disorder independent of ADHD. The objective of this study was to examine the neural substrates of cue-related preparatory processes associated with SCT symptoms versus inattentive symptoms in a group of adolescents with ADHD. We also compared cue-related effects in the entire ADHD group compared with a group of typically developing (TD peers. A modified cued flanker paradigm and fMRI examined brain activity associated with attention preparation and motor response preparation. Between group contrasts between the ADHD and TD group revealed significant hypoactivity in the ADHD group during general attention preparation in the supplementary motor area (SMA and in the right superior parietal lobe (SPL during response preparation. In the ADHD group, greater numbers of SCT symptoms were associated with hypoactivity in the left SPL to cues in general whereas greater numbers of inattentive symptoms were associated with greater activity in the SMA to cues that provided no information and less activity in the thalamus during response preparation. Hypoactivity in the SPL with increasing SCT symptoms may be associated with impaired reorienting or shifting of attention. Altered activity in the SMA and thalamus with increasing inattention may be associated with a general problem with response preparation, which may also reflect inefficient processing of the response preparation cue. Our results support a degree of differentiation between SCT and inattentive symptom profiles within adolescents with ADHD.

  16. Pathological mechanism for delayed hyperenhancement of chronic scarred myocardium in contrast agent enhanced magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Jian Wang

    Full Text Available OBJECTIVES: To evaluate possible mechanism for delayed hyperenhancement of scarred myocardium by investigating the relationship of contrast agent (CA first pass and delayed enhancement patterns with histopathological changes. MATERIALS AND METHODS: Eighteen pigs underwent 4 weeks ligation of 1 or 2 diagonal coronary arteries to induce chronic infarction. The hearts were then removed and perfused in a Langendorff apparatus. The hearts firstly experienced phosphorus 31 MR spectroscopy. The hearts in group I (n = 9 and II (n = 9 then received the bolus injection of Gadolinium diethylenetriamine pentaacetic acid (0.05 mmol/kg and gadolinium-based macromolecular agent (P792, 15 µmol/kg, respectively. First pass T2* MRI was acquired using a gradient echo sequence. Delayed enhanced T1 MRI was acquired with an inversion recovery sequence. Masson's trichrome and anti- von Willebrand Factor (vWF staining were performed for infarct characterization. RESULTS: Wash-in of both kinds of CA caused the sharp and dramatic T2* signal decrease of scarred myocardium similar to that of normal myocardium. Myocardial blood flow and microvessel density were significantly recovered in 4-week-old scar tissue. Steady state distribution volume (ΔR1 relaxation rate of Gd-DTPA was markedly higher in scarred myocardium than in normal myocardium, whereas ΔR1 relaxation rate of P792 did not differ significantly between scarred and normal myocardium. The ratio of extracellular volume to the total water volume was significantly greater in scarred myocardium than in normal myocardium. Scarred myocardium contained massive residual capillaries and dilated vessels. Histological stains indicated the extensively discrete matrix deposition and lack of cellular structure in scarred myocardium. CONCLUSIONS: Collateral circulation formation and residual vessel effectively delivered CA into scarred myocardium. However, residual vessel without abnormal hyperpermeability allowed Gd

  17. Perfusion MRI (dynamic susceptibility contrast imaging) with different measurement approaches for the evaluation of blood flow and blood volume in human gliomas

    DEFF Research Database (Denmark)

    Thomsen, Henrik; Larsson, Elna-Marie; Steffensen, Elena

    2012-01-01

    Background: Perfusion magnetic resonance imaging (MRI) is increasingly used in the evaluation of brain tumors. Relative cerebral blood volume (rCBV) is usually obtained by dynamic susceptibility contrast (DSC) MRI using normal appearing white matter as reference region. The emerging perfusion...... glioblastomas. Results: rCBF and rCBV measurements obtained with the maximum perfusion method were correlated when normalized to white matter (r ¼ 0.60) and to the cerebellum (r ¼ 0.49). Histogram analyses of rCBF and rCBV showed that mean and median values as well as skewness and peak position were correlated...

  18. FUNCTIONAL-ANATOMY OF THE SOFT-TISSUES OF THE HAND AND WRIST - INVIVO EXCURSION MEASUREMENT OF THE FLEXOR POLLICIS LONGUS-TENDON USING MRI

    NARCIS (Netherlands)

    HAM, SJ; KONINGS, JG; WOLF, RFE; MOOYAART, EL

    1993-01-01

    Magnetic resonance imaging (MRI) of the flexor pollicis longus-tendon (FPL-tendon) with the thumb in different positions allows the in vivo assessment of its abduction-adduction/flexion excursion. Measurements can also be performed in different positions of the wrist. In our study, the mean excursio

  19. Quantitative and Morphologic Change Associated with Breast Cancer-Related Lymphedema. Comparison of 3.0T MRI to External Measures

    OpenAIRE

    Gardner, Gregory C.; Nickerson, Joshua P.; Watts, Richard; Nelson, Lee; Dittus, Kim L.; O'Brien, Patricia J.

    2014-01-01

    Introduction: Lymphedema is a chronic disease of increasing importance to cancer survivors. A tape measurement tool used for lymphedema relies on indirect volume calculations based on external circumference, which may not reflect the true extent of abnormal fluid accumulation accurately. Fluid-sensitive MRI sequences may be able to delineate the severity of this condition more precisely and thus also monitor response to therapy.

  20. Comparison of manual tracing versus a semiautomatic radial measurement method in temporal lobe MRI volumetry for pharmacoresistant epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Christian-Andreas; Scorzin, Jasmin; Schramm, Johannes [University of Bonn, Department of Neurosurgery, Bonn (Germany); Koenig, Roy; Urbach, Horst [University of Bonn, Department of Radiology Neuroradiology, Bonn (Germany); Fimmers, Rolf [University of Bonn, Institute of Medical Biometry, Informatics and Epidemiology, Bonn (Germany); Zentner, Josef [University of Freiburg, Department of Neurosurgery, Freiburg (Germany); Lehmann, Thomas-Nicolas [Charite-University Medicine Berlin, Department of Neurosurgery, Berlin (Germany)

    2007-03-15

    The aim of this study was to test a modified radial semiautomated volumetry technique (radial divider technique, RDT) versus the manual volumetry technique (MVT) for proportionality of temporal subvolumes in 30 patients with drug-resistant temporal lobe epilepsy. Included in the study were 30 patients (15 female, 15 male; mean age 39.6 years) with pharmacoresistant epilepsy (mean duration 26.6 years). MRI studies were performed preoperatively on a 1.5-T scanner. All image processing steps and volume measurements were performed using ANALYZE software. The volumes of six subregions were measured bilaterally; these included the superior temporal gyrus (STG), middle + inferior temporal gyrus (MITG), fusiform gyrus (FG), parahippocampal gyrus (PHG), amygdala (AM), and hippocampus (HP). Linear regression was used to investigate the relationship between the comparable subvolumes obtained with MVT and RDT. Very high correlations (R {sup 2} >0.95) between RDT and MVT were observed for the STG + MITG and the STG + MITG + FG, but low correlations for the PHG subvolumes and the combined PHG + HP + AM subvolumes. These observations were independent of the side of the pathology and of hemisphere. The two measurement techniques provided highly reliable proportional results. This series in a homogeneous group of TLE patients suggests that the much quicker RDT is suitable for determining the volume of temporolateral and laterobasal temporal lobe compartments, of both the affected and the non-affected side and the right and left hemisphere. (orig.)

  1. Velocity Measurement in Carotid Artery: Quantitative Comparison of Time-Resolved 3D Phase-Contrast MRI and Image-based Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    Sarrami-Foroushani

    2015-10-01

    Full Text Available Background Understanding hemodynamic environment in vessels is important for realizing the mechanisms leading to vascular pathologies. Objectives Three-dimensional velocity vector field in carotid bifurcation is visualized using TR 3D phase-contrast magnetic resonance imaging (TR 3D PC MRI and computational fluid dynamics (CFD. This study aimed to present a qualitative and quantitative comparison of the velocity vector field obtained by each technique. Subjects and Methods MR imaging was performed on a 30-year old male normal subject. TR 3D PC MRI was performed on a 3 T scanner to measure velocity in carotid bifurcation. 3D anatomical model for CFD was created using images obtained from time-of-flight MR angiography. Velocity vector field in carotid bifurcation was predicted using CFD and PC MRI techniques. A statistical analysis was performed to assess the agreement between the two methods. Results Although the main flow patterns were the same for the both techniques, CFD showed a greater resolution in mapping the secondary and circulating flows. Overall root mean square (RMS errors for all the corresponding data points in PC MRI and CFD were 14.27% in peak systole and 12.91% in end diastole relative to maximum velocity measured at each cardiac phase. Bland-Altman plots showed a very good agreement between the two techniques. However, this study was not aimed to validate any of methods, instead, the consistency was assessed to accentuate the similarities and differences between Time-resolved PC MRI and CFD. Conclusion Both techniques provided quantitatively consistent results of in vivo velocity vector fields in right internal carotid artery (RCA. PC MRI represented a good estimation of main flow patterns inside the vasculature, which seems to be acceptable for clinical use. However, limitations of each technique should be considered while interpreting results.

  2. Cine MRI of hypertrophic cardiomyopathy

    International Nuclear Information System (INIS)

    Cine MRI was performed using 1.5T or 0.5T MR units in eleven patients with hypertrophic cardiomyopathy. Septal and posterior wall thickness measured by cine MRI correlated well with those obtained by ultrasonographic cardiogram. In hypertrophic obstructive cardiomyopathy, cine MRI demonstrated the site and nature of obstructive change in left ventricle. Cine MRI also showed flow void due to mitral regurgitation successfully. We considered cine MRI is useful means to evaluate the anatomical and functional findings in hypertrophic cardiomyopathy. (author)

  3. Aggression and Quantitative MRI Measures of Caudate in Patients With Chronic Schizophrenia or Schizoaffective Disorder

    OpenAIRE

    Hoptman, Matthew J.; Volavka, Jan; Czobor, Pál; Gerig, Guido; Chakos, Miranda; Blocher, Joseph; Citrome, Leslie L; Sheitman, Brain; Lindenmayer, Jean-Pierre; Lieberman, Jeffrey A.; Bilder, Robert M.

    2006-01-01

    Caudate dysfunction is implicated in schizophrenia. However, little is known about the relationship between aggression and caudate volumes. Forty-nine patients received magnetic resonance imaging scanning in a double-blind treatment study in which aggression was measured. Caudate volumes were computed using a semiautomated method. The authors measured aggression with the Overt Aggression Scale and the Positive and Negative Syndrome Scale. Larger caudate volumes were associated with greater le...

  4. Validity of soft-tissue thickness of calf measured using MRI for assessing unilateral lower extremity lymphoedema secondary to cervical and endometrial cancer treatments

    International Nuclear Information System (INIS)

    Aim: To determine whether soft-tissue thickness of the calf measured using MRI could be valid for assessing unilateral lower extremity lymphoedema (LEL) secondary to cervical and endometrial cancer treatments. Materials and methods: Seventy women with unilateral LEL and 25 without LEL after cervical or endometrial cancer treatments underwent MRI examinations of their calves. Total thickness of soft-tissue (TT), muscle thickness (MT), and subcutaneous tissue thickness (STT) of the calf, and the difference between the affected and contralateral unaffected calf regarding TT (DTT), MT (DMT), and STT (DSTT) were obtained using fat-suppressed T2-weighted imaging in the middle of the calves. The volume of the calf and difference in volume (DV) between calves were obtained by the method of water displacement. Statistical analysis was performed to determine the validity of MRI measurements by volume measurements in staging LEL. Results: There was a close correlation between volume and TT for the affected (r = 0.927) or unaffected calves (r = 0.896). STT of the affected calf, and DTT or DSTT of the calves were closely correlated with volume of the affected calf or DV of the calves (all p < 0.05). Multivariate analysis showed significant differences in TT, STT, volume of the affected calf, DTT, DSTT, and DV between stages except in volume of the affected calf or in DV between stage 0 and 1. For staging LEL, DSTT showed the best discrimination ability among all the parameters. Conclusions: Soft-tissue thickness of the calf measured at MRI could be valid for quantitatively staging unilateral LEL, and DSTT of the calves could be the best classifying factor. - Highlights: • The soft tissue thickness of calves on MRI could quantitatively assess secondary LEL. • Calf soft tissue thickness indicated concurrent or construct validity of calf volume. • The difference of subcutaneous tissue thickness of calves could be used to stage LEL

  5. Respiration gating and Bloch fitting improve pH measurements with acidoCEST MRI in an ovarian orthotopic tumor model

    Science.gov (United States)

    Jones, Kyle M.; Randtke, Edward A.; Howison, Christine M.; Pagel, Mark D.

    2016-03-01

    We have developed a MRI method that can measure extracellular pH in tumor tissues, known as acidoCEST MRI. This method relies on the detection of Chemical Exchange Saturation Transfer (CEST) of iopamidol, an FDA-approved CT contrast agent that has two CEST signals. A log10 ratio of the two CEST signals is linearly correlated with pH, but independent of agent concentration, endogenous T1 relaxation time, and B1 inhomogeneity. Therefore, detecting both CEST effects of iopamidol during in vivo studies can be used to accurately measure the extracellular pH in tumor tissues. Past in vivo studies using acidoCEST MRI have suffered from respiration artifacts in orthotopic and lung tumor models that have corrupted pH measurements. In addition, the non-linear fitting method used to analyze results is unreliable as it is subject to over-fitting especially with noisy CEST spectra. To improve the technique, we have recently developed a respiration gated CEST MRI pulse sequence that has greatly reduced motion artifacts, and we have included both a prescan and post scan to remove endogenous CEST effects. In addition, we fit the results by parameterizing the contrast of the exogenous agent with respect to pH via the Bloch equations modified for chemical exchange, which is less subject to over-fitting than the non-linear method. These advances in the acidoCEST MRI technique and analysis methods have made pH measurements more reliable, especially in areas of the body subject to respiratory motion.

  6. Influence of fat-water separation and spatial resolution on automated volumetric MRI measurements of fibroglandular breast tissue.

    Science.gov (United States)

    Wengert, Georg J; Pinker-Domenig, Katja; Helbich, Thomas H; Vogl, Wolf-Dieter; Clauser, Paola; Bickel, Hubert; Marino, Maria-Adele; Magometschnigg, Heinrich F; Baltzer, Pascal A

    2016-06-01

    The aim of this study was to investigate the influence of fat-water separation and spatial resolution in MRI on the results of automated quantitative measurements of fibroglandular breast tissue (FGT). Ten healthy volunteers (age range, 28-71 years; mean, 39.9 years) were included in this Institutional Review Board-approved prospective study. All measurements were performed on a 1.5-T scanner (Siemens, AvantoFit) using an 18-channel breast coil. The protocols included isotropic (Di) [TR/TE1 /TE2  = 6.00 ms/2.45 ms/2.67 ms; flip angle, 6.0°; 256 slices; matrix, 360 × 360; 1 mm isotropic; field of view, 360°; acquisition time (TA) = 3 min 38 s] and anisotropic (Da) (TR/TE1 /TE2  = 10.00 ms/2.39 ms/4.77 ms; flip angle, 24.9°; 80 slices; matrix 360 × 360; voxel size, 0.7 × 0.7 × 2.0 mm(3) ; field of view, 360°; TA = 1 min 25 s) T1 three-dimensional (3D) fast low-angle shot (FLASH) Dixon sequences, and a T1 3D FLASH sequence with the same resolution (T1 ) without (TR/TE = 11.00 ms/4.76 ms; flip angle, 25.0°; 80 slices; matrix, 360 × 360; voxel size, 0.7 × 0.7 × 2.0 mm(3) ; field of view, 360°; TA = 50 s) and with (TR/TE = 29.00 ms/4.76 ms; flip angle, 25.0°; 80 slices; matrix, 360 × 360; voxel size, 0.7 × 0.7 × 2.0 mm(3) ; field of view, 360°; TA = 2 min 35 s) fat saturation. Repeating volunteer measurements after 20 min and repositioning were used to assess reproducibility. An automated and quantitative volumetric breast density measurement system was used for FGT calculation. FGT with Di, Da and T1 measured 4.6-63.0% (mean, 30.6%), 3.2-65.3% (mean, 32.5%) and 1.7-66.5% (mean, 33.7%), respectively. The highest correlation between different MRI sequences was found with the Di and Da sequences (R(2)  = 0.976). Coefficients of variation (CVs) for FGT calculation were higher in T1 (CV = 21.5%) compared with Dixon (Di, CV = 5

  7. Inverse correlation between cerebral blood flow measured by continuous arterial spin-labeling (CASL) MRI and neurocognitive function in children with sickle cell anemia (SCA)

    OpenAIRE

    Strouse, John J.; Cox, Christiane S.; Melhem, Elias R.; Lu, Hanzhang; Kraut, Michael A.; Razumovsky, Alexander; Yohay, Kaleb; van Zijl, Peter C.; Casella, James F.

    2006-01-01

    Overt stroke, clinically “silent” cerebral infarct, and neurocognitive impairment are frequent complications of sickle cell anemia (SCA). Current imaging techniques have limited sensitivity and specificity to identify children at risk for neurocognitive impairment. We prospectively evaluated 24 children with SCA with a neurologic exam, complete blood count, transcranial Doppler ultrasound (TCD), measurement of intelligence quotient (IQ), and magnetic resonance imaging (MRI) with measurement o...

  8. Measurements of the normal fetal brain at gestation weeks 17 to 23: a MRI study

    International Nuclear Information System (INIS)

    To obtain measurements of the normal fetal brain before 24 weeks of gestation (GW), a deadline for medical decisions on fetal viability in a large number of countries. We retrospectively reviewed 70 normal MR examinations of fetuses aged GW 17 to 23. The fronto-occipital diameter, the cerebral bi-parietal diameter, the transverse cerebellar diameter, the vermian height, and antero-posterior diameter were measured. The median, maximum, and minimum values for each parameter were displayed for each individual GW. The recorded data might contribute to a better assessment of fetal health by providing normal boundaries for the brain growth. (orig.)

  9. Measurements of the normal fetal brain at gestation weeks 17 to 23: a MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Canto Moreira, Nuno [Neuroradiology Section C. Campos Costa, Porto (Portugal); Uppsala University, Department of Radiology, Uppsala (Sweden); Teixeira, Joao [H. G. S. Antonio, Department of Neuroradiology, Porto (Portugal); Themudo, Raquel; Raininko, Raili; Wikstrom, Johan [Uppsala University, Department of Radiology, Uppsala (Sweden); Amini, Hashem; Axelsson, Ove [Uppsala University, Department of Women' s and Children' s Health, Uppsala (Sweden)

    2011-01-15

    To obtain measurements of the normal fetal brain before 24 weeks of gestation (GW), a deadline for medical decisions on fetal viability in a large number of countries. We retrospectively reviewed 70 normal MR examinations of fetuses aged GW 17 to 23. The fronto-occipital diameter, the cerebral bi-parietal diameter, the transverse cerebellar diameter, the vermian height, and antero-posterior diameter were measured. The median, maximum, and minimum values for each parameter were displayed for each individual GW. The recorded data might contribute to a better assessment of fetal health by providing normal boundaries for the brain growth. (orig.)

  10. 3 BOLD MRI with low intrascan variability and high reproducibilityy of limb oxygenation measurements

    NARCIS (Netherlands)

    Hedstrom, E.; Patel, A.S.; Voigt, T.; Modarai, B.; Schaeffter, T.; Smith, A.; Nagel, E.

    2012-01-01

    Current imaging methods cannot reliably quantify muscle oxygenationin patients with limb ischaemia. We propose a high-resolution BOLD sequence whereby edge artefacts and vessels may be excluded from measurements. CONCLUSIONS: The sequence and analysis proposed shows lowintrascan variability and high

  11. MRI measurements of water diffusion: impact of region of interest selection on ischemic quantification

    Energy Technology Data Exchange (ETDEWEB)

    Ozsunar, Yelda E-mail: yozsunar@adu.edu.tr; Koseoglu, Kutsi; Huisman, Thierry A.G.M.; Koroshetz, Walter; Sorensen, A. Gregory

    2004-09-01

    Objective: To investigate the effect of ADC heterogeneity on region of interest (ROI) measurement of isotropic and anisotropic water diffusion in acute (<12 h) cerebral infarctions. Methods and materials: Full diffusion tensor images were retrospectively analyzed in 32 patients with acute cerebral infarction. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were measured in ischemic lesions and in the corresponding contralateral, normal appearing brain by using four ROIs for each patient. The 2x2 pixel square ROIs were placed in the center, the lateral rim and the medial rim of the infarction. In addition, the whole volume of the infarction was measured using a free hand method. Each ROI value obtained from the ischemic lesion was normalized using contralateral normal ROI values. Results: The localization of the ROIs in relation to the ischemic lesion significantly affected ADC measurement (P<0.01, using Friedman test), but not FA measurement (P=0.25). Significant differences were found between ADC values of the center of the infarction versus whole volume (P<0.01), and medial rim versus whole volume of infarction (P<0.001) with variation of relative ADC values up to 11%. The differences of absolute ADC for these groups were 22 and 23%, respectively. The lowest ADC was found in the center, followed by medial rim, lateral rim and whole volume of infarction. Conclusion: ADC quantification may provide variable results depending on ROI method. The ADC and FA values, obtained from the center of infarction tend to be lower compared to the periphery. The researchers who try to compare studies or work on ischemic quantification should be aware of these differences and effects.

  12. MRI-based blood oxygen saturation measurements in infants and children with congenital heart disease

    International Nuclear Information System (INIS)

    Background: Vessel oxygen saturation can be determined with MR oximetry using an in vivo measurement of signal decay (T2) and the calibration curve relating T2 to blood oxygen saturation (%HbO2), where: 1/T2=1/T2O+K (1-%HbO2/100)2 and K is a constant parameter which correlates with measured fibrinogen levels. The ability to noninvasively measure %HbO2 in cardiac chambers and vessels has enormous potential in children with congenital heart disease (CHD). Objective: The purpose of the study was to prospectively characterize the T2-%HbO2 relationship in infants where T2-%HbO2 is the realtionship between T2 and %HbO2 (blood oxygen saturation) expressed by the equation given above, and to determine whether adult values for K and T2O (where T2O is the T2 of fully oxygenated blood) can be extrapolated to pediatric patients with CHD. A second objective was to apply this method to calculate the %HbO2 in vivo using MR imaging in infants with CHD. Materials and methods: Fifteen patients with CHD undergoing cardiac catheterization (9 male; 6 female), median age 8 months, were recruited for the calibration study. T2O and K were measured directly from blood samples, compared with the values estimated from adult population statistics, and plotted against hematocrit and fibrinogen, respectively. In four studies of infants with CHD, T2 measurements were converted to %HbO2 using the calibration curve. Results: The T2-%HbO2 relationship in infants correlated with the adult calibration statistics (1/T2O vs. hematocrit, r=0.77; K vs. fibrinogen, r=0.61). Our initial in vivo studies demonstrated that the MR oximetry reflected the expected oxygen saturations. Conclusion: Adult values for T2-%HbO2 calibration can be used to measure blood oxygen saturation in vivo in children with CHD. (orig.)

  13. Measurement with microscopic MRI and simulation of flow in different aneurysm models

    Energy Technology Data Exchange (ETDEWEB)

    Edelhoff, Daniel, E-mail: daniel.edelhoff@tu-dortmund.de; Frank, Frauke; Heil, Marvin; Suter, Dieter [Experimental Physics III, TU Dortmund University, Otto-Hahn-Street 4, Dortmund 44227 (Germany); Walczak, Lars; Weichert, Frank [Computer Science VII, TU Dortmund University, Otto-Hahn-Street 16, Dortmund 44227 (Germany); Schmitz, Inge [Institute for Pathology, Ruhr Universität Bochum, Bürkle-de-la-Camp-Platz 1, Bochum 44789 (Germany)

    2015-10-15

    Purpose: The impact and the development of aneurysms depend to a significant degree on the exchange of liquid between the regular vessel and the pathological extension. A better understanding of this process will lead to improved prediction capabilities. The aim of the current study was to investigate fluid-exchange in aneurysm models of different complexities by combining microscopic magnetic resonance measurements with numerical simulations. In order to evaluate the accuracy and applicability of these methods, the fluid-exchange process between the unaltered vessel lumen and the aneurysm phantoms was analyzed quantitatively using high spatial resolution. Methods: Magnetic resonance flow imaging was used to visualize fluid-exchange in two different models produced with a 3D printer. One model of an aneurysm was based on histological findings. The flow distribution in the different models was measured on a microscopic scale using time of flight magnetic resonance imaging. The whole experiment was simulated using fast graphics processing unit-based numerical simulations. The obtained simulation results were compared qualitatively and quantitatively with the magnetic resonance imaging measurements, taking into account flow and spin–lattice relaxation. Results: The results of both presented methods compared well for the used aneurysm models and the chosen flow distributions. The results from the fluid-exchange analysis showed comparable characteristics concerning measurement and simulation. Similar symmetry behavior was observed. Based on these results, the amount of fluid-exchange was calculated. Depending on the geometry of the models, 7% to 45% of the liquid was exchanged per second. Conclusions: The result of the numerical simulations coincides well with the experimentally determined velocity field. The rate of fluid-exchange between vessel and aneurysm was well-predicted. Hence, the results obtained by simulation could be validated by the experiment. The

  14. The effect of theta-burst TMS on cognitive control networks measured with resting state fMRI

    Directory of Open Access Journals (Sweden)

    Caterina Gratton

    2013-12-01

    Full Text Available It has been proposed that two relatively independent cognitive control networks exist in the brain: the cingulo-opercular network (CO and the fronto-parietal network (FP. Past work has shown that chronic brain lesions affect these networks independently. It remains unclear, however, how these two networks are affected by acute brain disruptions. To examine this, we conducted a within-subject theta-burst transcranial magnetic stimulation (TBS experiment in healthy individuals that targeted left anterior insula/frontal operculum (L aI/fO, a region in the CO network, left dorsolateral prefrontal cortex (L dlPFC, a region in the FP network, or left primary somatosensory cortex (L S1, an experimental control region. Functional connectivity was measured in resting state fMRI scans collected before and after continuous TBS on each day. We found that TBS was accompanied by generalized increases in network connectivity, especially FP network connectivity, after TBS to either region involved in cognitive control. Whole-brain analyses demonstrated that the L dlPFC and L aI/fO showed increased connectivity with regions in frontal, parietal, and cingulate cortex after TBS to either L dlPFC or L aI/fO, but not to L S1. These results suggest that acute disruption by TBS to cognitive control regions causes widespread changes in network connectivity not limited to the targeted networks.

  15. fMRI Data Analysis Using Dempster-Shafer Method with Estimating Voxel Selectivity by Belief Measure

    OpenAIRE

    ATTIA Abdelouahab; MOUSSAOUI Abdelouahab; Taleb-Ahmed, Abdelmalik

    2016-01-01

    In the functional Magnetic Resonance Imaging (fMRI) data analysis, detecting the activated voxels is a challenging research problem where the existing methods have shown some limits. We propose a new method wherein brain mapping is done based on Dempster-Shafer theory of evidence (DS) that is a useful method in uncertain representation analysis. Dempster-Shafer allows finding the activated regions by checking the activated voxels in fMRI data. The activated brain areas related to a given stim...

  16. PHYCAA: Data-driven measurement and removal of physiological noise in BOLD fMRI

    DEFF Research Database (Denmark)

    Churchill, Nathan W.; Yourganov, Grigori; Spring, Robyn;

    2012-01-01

    with physiological noise, and real data-driven model prediction and reproducibility, for both block and event-related task designs. This is demonstrated compared to no physiological noise correction, and to the widely used RETROICOR (Glover et al., 2000) physiological denoising algorithm, which uses...... that is task- and subject-dependent. We also demonstrate that increasing dimensionality of such physiological noise is correlated with increasing variability in externally-measured respiratory and cardiac processes. Using PHYCAA as a denoising technique significantly improves simulated signal detection...

  17. Application of fMRI to obesity research: differences in reward pathway activation measured with fMRI BOLD during visual presentation of high and low calorie foods

    Science.gov (United States)

    Tsao, Sinchai; Adam, Tanja C.; Goran, Michael I.; Singh, Manbir

    2012-03-01

    The factors behind the neural mechanisms that motivate food choice and obesity are not well known. Furthermore, it is not known when these neural mechanisms develop and how they are influenced by both genetic and environmental factors. This study uses fMRI together with clinical data to shed light on the aforementioned questions by investigating how appetite-related activation in the brain changes with low versus high caloric foods in pre-pubescent girls. Previous studies have shown that obese adults have less striatal D2 receptors and thus reduced Dopamine (DA) signaling leading to the reward-deficit theory of obesity. However, overeating in itself reduces D2 receptor density, D2 sensitivity and thus reward sensitivity. The results of this study will show how early these neural mechanisms develop and what effect the drastic endocrinological changes during puberty has on these mechanisms. Our preliminary results showed increased activations in the Putamen, Insula, Thalamus and Hippocampus when looking at activations where High Calorie > Low Calorie. When comparing High Calorie > Control and Low Calorie > Control, the High > Control test showed increased significant activation in the frontal lobe. The Low > Control also yielded significant activation in the Left and Right Fusiform Gyrus, which did not appear in the High > Control test. These results indicate that the reward pathway activations previously shown in post-puberty and adults are present in pre-pubescent teens. These results may suggest that some of the preferential neural mechanisms of reward are already present pre-puberty.

  18. Belowground plant development measured with magnetic resonance imaging (MRI: exploiting the potential for non-invasive trait quantification using sugar beet as a proxy

    Directory of Open Access Journals (Sweden)

    Ralf eMetzner

    2014-09-01

    Full Text Available Both structural and functional properties of belowground plant organs are critical for the development and yield of plants but, compared to the shoot, much more difficult to observe due to soil opacity. Many processes concerning the belowground plant performance are not fully understood, in particular spatial and temporal dynamics and their interrelation with environmental factors. We used Magnetic Resonance Imaging (MRI as a noninvasive method to evaluate which traits can be measured when a complex plant organ is monitored in-vivo while growing in the soil. We chose sugar beet (Beta vulgaris ssp. vulgaris as a model system. The beet consists mainly of root tissues, is rather complex regarding tissue structure and responses to environmental factors, and thereby a good object to test the applicability of MRI for 3D phenotyping approaches. Over a time period of up to 3 months, traits such as beet morphology or anatomy were followed in the soil and the effect of differently sized pots on beet fresh weight calculated from MRI data was studied. There was a clear positive correlation between the pot size and the increase in fresh weight of a sugar beet over time. Since knowledge of the development of internal beet structures with several concentric cambia, vascular and parenchyma rings is still limited, we consecutively acquired 3D volumetric images on individual plants using the MRI contrast parameter T2 to map the development of rings at the tissue level. This demonstrates that MRI provides versatile protocols to non-invasively measure plant traits in the soil. It opens new avenues to investigate belowground plant performance under adverse environmental conditions such as drought, nutrient shortage or soil compaction to seek for traits of belowground organs making plants more resilient to stress.

  19. Changes in foetal liver T2* measurements by MRI in response to maternal oxygen breathing: application to diagnosing foetal growth restriction

    International Nuclear Information System (INIS)

    The motivation of the project was to investigate the use of oxygen-challenge magnetic resonance imaging (OC-MRI) as a method of diagnosing foetal growth restriction. Foetal growth restriction is associated with restricted foetal oxygen supply and is also associated with increased risks of perinatal mortality and morbidity, and a number of serious and chronic health problems. Measurements of T2* relaxation time, an MRI parameter which increases with blood oxygenation, were made in the right lobe of the foetal liver in 80 singleton pregnancies, before and after the mother breathed oxygen. The groups consisted of 41 foetuses with normal growth and 39 with apparent growth restriction. The mean ± SD gestational age at scanning was 35 ± 3 weeks. Changes in foetal liver T2* on maternal oxygen breathing showed no significant difference between the groups therefore the OC-MRI protocol used in this study has no value in the diagnosis of foetal growth restriction. A secondary finding was that a significant positive correlation of T2* change with gestational age was observed. Future studies on the use of oxygen-challenge MRI to investigate foetal growth restriction may therefore need to control for gestational age at the time of MR scanning in order to observe any underlying foetal growth-related effects

  20. Comparison of relative pressures calculated from PC-MRI and SPIV with catheter-based pressure measurements in a stenotic phantom model

    Science.gov (United States)

    Khodarahmi, Iman; Shakeri, Mostafa; Kotys-Traughber, Melanie; Sharp, Michael K.; Amini, Amir A.

    2012-03-01

    This paper describes an experimental system for validation of an approach to non-invasive determination of pressure gradients in stenotic flows as encountered in peripheral arterial disease. Pressure gradient across a Gaussian-shaped 87% area stenosis phantom was estimated by solving the pressure Poisson equation (PPE) for a steady flow mimicking the blood flow through the human iliac artery. The velocity field needed to solve the pressure equation was obtained using Phase-Contrast MRI (PC-MRI) and Stereoscopic Particle Image Velocimetry (SPIV). Steady flow rate of 46.9 ml/s was used, which corresponds to a Reynolds number of 188 and 595 at the inlet and stenosis throat, respectively (in the range of mean Reynolds number encountered, in-vivo). Results of PC-MRI and SPIV have been compared to the pressures measured directly by a pressure catheter transducer. The reconstructed pressure drop along the centerline overestimates the catheter reference pressure drop by 8.5% and 10.5% for PC_MRI and SPIV methods, respectively.

  1. Hemodynamic significance of coronary stenosis by vessel attenuation measurement on CT compared with adenosine perfusion MRI

    Energy Technology Data Exchange (ETDEWEB)

    Dekker, Martijn A.M. den; Pelgrim, Gert Jan; Pundziute, Gabija; Heuvel, Edwin R. van den; Oudkerk, Matthijs; Vliegenthart, Rozemarijn, E-mail: r.vliegenthart@umcg.nl

    2015-01-15

    Highlights: • The majority of anatomical coronary stenoses do not cause myocardial ischemia. • cCTA-derived CCO decrease expresses luminal density gradient across stenosis. • CCO decrease differentiates between anatomical stenoses with and without associated myocardial ischemia. • CCO decrease assessment can exclude the majority of stenoses without hemodynamic significance. - Abstract: Purpose: We assessed the association between corrected contrast opacification (CCO) based on coronary computed tomography angiography (cCTA) and inducible ischemia by adenosine perfusion magnetic resonance imaging (APMR). Methods: Sixty cardiac asymptomatic patients with extra-cardiac arterial disease (mean age 64.4 ± 7.7 years; 78% male) underwent cCTA and APMR. Luminal CT attenuation values (Hounsfield Units) were measured in coronary arteries from proximal to distal, with additional measurements across sites with >50% lumen stenosis. CCO was calculated by dividing coronary CT attenuation by descending aorta CT attenuation. A reversible perfusion defect on APMR was considered as myocardial ischemia. Results: In total, 169 coronary stenoses were found. Seven patients had 8 perfusion defects on APMR, with 11 stenoses in corresponding vessels. CCO decrease across stenoses with hemodynamic significance was 0.144 ± 0.112 compared to 0.047 ± 0.104 across stenoses without hemodynamic significance (P = 0.003). CCO decrease in lesions with and without anatomical stenosis was similar (0.054 ± 0.116 versus 0.052 ± 0.101; P = 0.89). Using 0.20 as preliminary CCO decrease cut-off, hemodynamic significance would be excluded in 82.9% of anatomical stenoses. Conclusions: CCO decrease across coronary stenosis is associated with myocardial ischemia on APMR. CCO based on common cCTA data is a novel method to assess hemodynamic significance of anatomical stenosis.

  2. Hemodynamic significance of coronary stenosis by vessel attenuation measurement on CT compared with adenosine perfusion MRI

    International Nuclear Information System (INIS)

    Highlights: • The majority of anatomical coronary stenoses do not cause myocardial ischemia. • cCTA-derived CCO decrease expresses luminal density gradient across stenosis. • CCO decrease differentiates between anatomical stenoses with and without associated myocardial ischemia. • CCO decrease assessment can exclude the majority of stenoses without hemodynamic significance. - Abstract: Purpose: We assessed the association between corrected contrast opacification (CCO) based on coronary computed tomography angiography (cCTA) and inducible ischemia by adenosine perfusion magnetic resonance imaging (APMR). Methods: Sixty cardiac asymptomatic patients with extra-cardiac arterial disease (mean age 64.4 ± 7.7 years; 78% male) underwent cCTA and APMR. Luminal CT attenuation values (Hounsfield Units) were measured in coronary arteries from proximal to distal, with additional measurements across sites with >50% lumen stenosis. CCO was calculated by dividing coronary CT attenuation by descending aorta CT attenuation. A reversible perfusion defect on APMR was considered as myocardial ischemia. Results: In total, 169 coronary stenoses were found. Seven patients had 8 perfusion defects on APMR, with 11 stenoses in corresponding vessels. CCO decrease across stenoses with hemodynamic significance was 0.144 ± 0.112 compared to 0.047 ± 0.104 across stenoses without hemodynamic significance (P = 0.003). CCO decrease in lesions with and without anatomical stenosis was similar (0.054 ± 0.116 versus 0.052 ± 0.101; P = 0.89). Using 0.20 as preliminary CCO decrease cut-off, hemodynamic significance would be excluded in 82.9% of anatomical stenoses. Conclusions: CCO decrease across coronary stenosis is associated with myocardial ischemia on APMR. CCO based on common cCTA data is a novel method to assess hemodynamic significance of anatomical stenosis

  3. Upright MRI measurement of mechanical axis and frontal plane alignment as a new technique: a comparative study with weight bearing full length radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Liodakis, Emmanouil; Kenawey, Mohamed; Doxastaki, Iosifina; Krettek, Christian; Haasper, Carl; Hankemeier, Stefan [Medical School Hannover, Department of Trauma Surgery, Hannover (Germany)

    2011-07-15

    The purpose of this prospective study was to investigate the practicality, accuracy, and reliability of upright MR imaging as a new radiation-free technique for the measurement of mechanical axis. We used upright MRI in 15 consecutive patients (30 limbs, 44.7 {+-} 20.6 years old) to measure mechanical axis deviation (MAD), hip-knee-ankle (HKA) angle, leg length, and all remaining angles of the frontal plane alignment according to Paley (mLPFA, mLDTA, mMPTA, mLDTA, JLCA). The measurements were compared to weight bearing full length radiographs, which are considered to be the standard of reference for planning corrective surgery. FDA-approved medical planning software (MediCAD) was used for the above measurements. Intra- and inter-observer reproducibility using mean absolute differences was also calculated for both methods. The correlation coefficient between angles determined with upright MRI and weight bearing full length radiographs was high for mLPFA, mLDTA, mMPTA, mLDTA, and the HKA angle (r > 0.70). Mean interobserver and intraobserver agreements for upright MRI were also very high (r > 0.89). The leg length and the MAD were significantly underestimated by MRI (-3.2 {+-} 2.2 cm, p < 0.001 and -6.2 {+-} 4.4 mm, p = 0.006, respectively). With the exception of underestimation of leg length and MAD, upright MR imaging measurements of the frontal plane angles are precise and produce reliable, reproducible results. (orig.)

  4. Volume measurement of thalami in normal Chinese Han nationality adults by the high-resolution MRI

    International Nuclear Information System (INIS)

    Objective: To measure the volume of thalamus in 1000 healthy Chinese Han nationality adults, and to analyze the relationship between thalamic volume and age, sex, weight and cerebral volume, to provide reliable data for the construction of database of Chinese adults' digital standard brain. Methods: Totally 1000 healthy Chinese adults of Han nationality aged from 18 to 80 years were recruited.They were divided into 5 groups by age: 18-30, 31-40, 41-50, 51-60 and 61-80 years. Each group included 100 males and 100 females. Brain images were obtained on a 1.5 T MR, and the outline of thalami was drawn with Aquariusws software. Then the thalamic volume was calculated automatically. The volumes of left and right thalamus were compared by paired sample t-test. Thalamic volumes of the same side were compared between males and females by independent sample t-test. And thalamic volumes of different age groups were compared by one-way ANOVA. The relationships between thalamic volume and age, sex, weight and cerebral volume were analyzed respectively. Results: The males' standardized volumes of left and right thalamus of healthy Chinese Han nationality adults were (5776 ± 780), (5655 ± 759) mm3, and they were (5464 ±573), (5360 ± 542) mm3 for female. The males' thalamic volume was more than the females' on the same side (t=2.245, 2.200, P<0.01). The left thalamic volumes of various age groups were (6180 ± 534), (6047 ± 562), (5426 ± 471), (5552 ± 526), (4866 ± 552) mm3, respectively, while the right thalamic volumes of the 5 groups were (6069 ± 532), (5895 ± 539), (5357 ± 480), (5396 ± 445),(4791 ± 558)mm3, respectively. There were statistically significant difference among the 5 groups (F=165.686, 165.235, P<0.01). The left and right thalamic volume were all negatively correlated with age (r=-0.633, -0.645, P<0.05). Conclusions: With high resolution 1.5 T MR scanner,grey matter and white matter can be depicted clearly and the outline of

  5. Objective measurement of the distal resection margin by MRI of the fresh and fixed specimen after partial mesorectal excision for rectal cancer

    DEFF Research Database (Denmark)

    Bondeven, Peter; Hagemann-Madsen, Rikke H; Bro, Lise;

    2015-01-01

    measure the length of the distal resection margin in the fresh and fixed specimen following partial mesorectal excision for rectal cancer using magnetic resonance imaging (MRI) to document tissue shrinkage after surgical removal and fixation. MATERIAL AND METHODS: The length of the distal resection margin...... was measured by MRI of the fresh and fixed specimen and at histopathological examination of the fixed specimen in 10 patients who underwent surgery for upper rectal cancer. In addition, tissue shrinkage was estimated by measuring the total length of the fresh and fixed specimen and distance from the...... peritoneal reflection anteriorly to the distal cut edge of the specimen. RESULTS: Measured by MRI, the distal resection margin was in the range of 0.6-10.2 cm (mean, 4.6 cm) in the fresh specimen, and 0.5-6.2 cm (mean, 3.2 cm) in the fixed specimen. The tissue shrinkage ratio was a mean of 69% (interquartile...

  6. Determinants of renal tissue oxygenation as measured with BOLD-MRI in chronic kidney disease and hypertension in humans.

    Directory of Open Access Journals (Sweden)

    Menno Pruijm

    Full Text Available Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD and arterial hypertension (AHT. In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2* were calculated before and after administration of IV furosemide, a low R2* indicating a high tissue oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls. Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection, the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal tissue oxygenation.

  7. Spatial shrinkage/expansion patterns between breast density measured in two MRI scans evaluated by non-rigid registration

    Energy Technology Data Exchange (ETDEWEB)

    Lin Muqing; Chen, Jeon-Hor; Bahri, Shadfar; Nalcioglu, Orhan; Su Minying [Tu and Yuen Center for Functional Onco-Imaging, Department of Radiological Sciences, University of California, Irvine, CA (United States); Mehta, Rita S [Department of Medicine, University of California, Irvine, CA (United States); Chan Siwa, E-mail: msu@uci.edu [Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan (China)

    2011-09-21

    Breast MRI acquires many images from the breast, and computer-aided algorithms and display tools are often used to assist the radiologist's interpretation. Women with lifetime risk greater than 20% of developing breast cancer are recommended to receive annual screening MRI, but the current breast MRI computer-aided-diagnosis systems do not provide the necessary function for comparison of images acquired at different times. The purpose of this work was to develop registration methods for evaluating the spatial change pattern of fibroglandular tissue between two breast MRI scans of the same woman taken at different times. The registration method is based on rigid alignment followed by a non-rigid Demons algorithm. The method was tested on three different subjects who had different degrees of changes in the fibroglandular tissue, including two patients who showed different spatial shrinkage patterns after receiving neoadjuvant chemotherapy before surgery, and one control case from a normal volunteer. Based on the transformation matrix, the collapse of multiple voxels on the baseline images to one voxel on the follow-up images is used to calculate the shrinkage factor. Conversely, based on the reverse transformation matrix the expansion factor can be calculated. The shrinkage/expansion factor, the deformation magnitude and direction, as well as the Jacobian determinate at each location can be displayed in a 3D rendering view to show the spatial changes between two MRI scans. These different parameters show consistent results and can be used for quantitative evaluation of the spatial change patterns. The presented registration method can be further developed into a clinical tool for evaluating therapy-induced changes and for early diagnosis of breast cancer in screening MRI.

  8. Spatial shrinkage/expansion patterns between breast density measured in two MRI scans evaluated by non-rigid registration

    International Nuclear Information System (INIS)

    Breast MRI acquires many images from the breast, and computer-aided algorithms and display tools are often used to assist the radiologist's interpretation. Women with lifetime risk greater than 20% of developing breast cancer are recommended to receive annual screening MRI, but the current breast MRI computer-aided-diagnosis systems do not provide the necessary function for comparison of images acquired at different times. The purpose of this work was to develop registration methods for evaluating the spatial change pattern of fibroglandular tissue between two breast MRI scans of the same woman taken at different times. The registration method is based on rigid alignment followed by a non-rigid Demons algorithm. The method was tested on three different subjects who had different degrees of changes in the fibroglandular tissue, including two patients who showed different spatial shrinkage patterns after receiving neoadjuvant chemotherapy before surgery, and one control case from a normal volunteer. Based on the transformation matrix, the collapse of multiple voxels on the baseline images to one voxel on the follow-up images is used to calculate the shrinkage factor. Conversely, based on the reverse transformation matrix the expansion factor can be calculated. The shrinkage/expansion factor, the deformation magnitude and direction, as well as the Jacobian determinate at each location can be displayed in a 3D rendering view to show the spatial changes between two MRI scans. These different parameters show consistent results and can be used for quantitative evaluation of the spatial change patterns. The presented registration method can be further developed into a clinical tool for evaluating therapy-induced changes and for early diagnosis of breast cancer in screening MRI.

  9. Measuring the volume of caudate nucleus in healthy Chinese adults of the Han nationality on the high-resolution MRI

    International Nuclear Information System (INIS)

    Objective: To explore the normal range of the caudate nucleus' volume in Chinese adults of the Han nationality and provide morphological data for the construction of database for Chinese Standard Brain. Methods: This was a clinical multi-center study. One thousand Chinese healthy volunteers (age range =18 to 70) recruited from 16 hospitals were divided into 5 groups, i.e, Group A (age range = 18 to 30), B (age range =31 to 40), C (age range =41 to 50), D (age range =51 to 60), and E (age range =61 to 70). Each group contained 100 males and 100 females. All of the volunteers were scanned by MR using T1 weighted three-dimensional magnetization prepared rapid acquisition gradient echo sequence. The volume of caudate was measured manually using 3D volume analysis software. The difference of volumes of the caudate between male and female were analyzed by independent sample t-test, and among age groups by ANOVA. Pearson's correlation coefficient was used to characterize the relationship between volumes and age. The differences of measurements between left and right caudate nucleus were analyzed by paired t test. Results: (1) The mean volume of bilateral caudate nucleus in healthy Chinese adults was (10.973± 1.647) cm3. The mean volume of the the male's left and right caudate nucleus were (5.656±0.860) and (5.671±0.855) cm3 respectively,no significant differences were found between the volume of left and right caudate nucleus (t=1.230, P>0.05). The mean volume of the the female's left and right caudate nucleus were (5.287±0.774) and (5.331±0.766) cm3 respectively, and the right's was larger than the left's with significant differences (t=3.999, P<0.01); (2) Pearson correlation analysis showed a significant negative correlation between the nucleus volume and age (male and female's, left and right) (r=-0.561, -0.568, -0.548, -0.552, P<0.05). Conclusion: With high-resolution MRI and 3D volumetric analytic software (Midob), the volume of the caudate nucleus can be

  10. Cerebral hemodynamic changes measured by gradient-echo or spin-echo bolus tracking and its correlation to changes in ICA blood flow measured by phase-mapping MRI

    DEFF Research Database (Denmark)

    Marstrand, J.R.; Rostrup, Egill; Garde, Ellen; Larsson, Henrik B.W.

    2001-01-01

    Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC-MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase-mapping. Also examined was...... significant increase in CBF and CBV in response to ACZ, while SE-EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE-EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE-EPI and change in ICA flow. In...... conclusion, GE-EPI under the present condition was superior to SE-EPI in monitoring cerebral vascular changes...

  11. MRI-derived measurements of fibrous-cap and lipid-core thickness: the potential for identifying vulnerable carotid plaques in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Trivedi, Rikin A. [Addenbrooke' s Hospital, University Department of Radiology, Cambridge (United Kingdom); Addenbrooke' s Hospital, Academic Department of Neurosurgery, Cambridge (United Kingdom); U-King-Im, Jean-Marie; Graves, Martin J. [Addenbrooke' s Hospital, University Department of Radiology, Cambridge (United Kingdom); Horsley, Jo; Goddard, Martin [Papworth Hospital, Department of Histopathology, Papworth Everard (United Kingdom); Kirkpatrick, Peter J. [Addenbrooke' s Hospital, Academic Department of Neurosurgery, Cambridge (United Kingdom); Gillard, Jonathan H. [Addenbrooke' s Hospital, University Department of Radiology, Cambridge (United Kingdom); Addenbrooke' s Hospital, Hills Road, Box 219, Cambridge (United Kingdom)

    2004-09-01

    Vulnerable plaques have thin fibrous caps overlying large necrotic lipid cores. Recent studies have shown that high-resolution MR imaging can identify these components. We set out to determine whether in vivo high-resolution MRI could quantify this aspect of the vulnerable plaque. Forty consecutive patients scheduled for carotid endarterectomy underwent pre-operative in vivo multi-sequence MR imaging of the carotid artery. Individual plaque constituents were characterised on MR images. Fibrous-cap and lipid-core thickness was measured on MRI and histology images. Bland-Altman plots were generated to determine the level of agreement between the two methods. Multi-sequence MRI identified 133 corresponding MR and histology slices. Plaque calcification or haemorrhage was seen in 47 of these slices. MR and histology derived fibrous cap-lipid-core thickness ratios showed strong agreement with a mean difference between MR and histology ratios of 0.02 ({+-}0.04). The intra-class correlation coefficient between two readers for measurements was 0.87 (95% confidence interval, 0.73 and 0.93). Multi-sequence, high-resolution MR imaging accurately quantified the relative thickness of fibrous-cap and lipid-core components of carotid atheromatous plaques. This may prove to be a useful tool to characterise vulnerable plaques in vivo. (orig.)

  12. MRI-derived measurements of fibrous-cap and lipid-core thickness: the potential for identifying vulnerable carotid plaques in vivo

    International Nuclear Information System (INIS)

    Vulnerable plaques have thin fibrous caps overlying large necrotic lipid cores. Recent studies have shown that high-resolution MR imaging can identify these components. We set out to determine whether in vivo high-resolution MRI could quantify this aspect of the vulnerable plaque. Forty consecutive patients scheduled for carotid endarterectomy underwent pre-operative in vivo multi-sequence MR imaging of the carotid artery. Individual plaque constituents were characterised on MR images. Fibrous-cap and lipid-core thickness was measured on MRI and histology images. Bland-Altman plots were generated to determine the level of agreement between the two methods. Multi-sequence MRI identified 133 corresponding MR and histology slices. Plaque calcification or haemorrhage was seen in 47 of these slices. MR and histology derived fibrous cap-lipid-core thickness ratios showed strong agreement with a mean difference between MR and histology ratios of 0.02 (±0.04). The intra-class correlation coefficient between two readers for measurements was 0.87 (95% confidence interval, 0.73 and 0.93). Multi-sequence, high-resolution MR imaging accurately quantified the relative thickness of fibrous-cap and lipid-core components of carotid atheromatous plaques. This may prove to be a useful tool to characterise vulnerable plaques in vivo. (orig.)

  13. Tetrachloroethene degradation by reducing-agent enhanced Fe(II)/Fe(III) catalyzed percarbonate

    Science.gov (United States)

    Miao, Z.; Brusseau, M. L.; Lu, S.; Gu, X.; Yan, N.; Qiu, Z.; Sui, Q.

    2015-12-01

    This project investigated the effect of reducing agents on the degradation of tetrachloroethene(PCE) by Fe(II)/Fe(III) catalyzed sodium percarbonate (SPC). SPC possesses similar function as liquid H2O2, such that free H2O2 is released into solution when percarbonate is mixed with water. The addition of reducing agents, including hydroxylamine hydrochloride, sodium sulfite, ascorbic acid and sodium ascorbate, accelerated the Fe(III)/Fe(II) redoxcycle, leading to a relatively steady Fe(II) concentration and higher production of free radicals. This, in turn, resulted in enhanced PCE oxidation by SPC, with almost complete PCE removal obtained for appropriate Fe and SPC concentrations.The results of chemical probe tests, using nitrobenzene and carbon tetrachloride, demonstrated that HO● was the predominant radical in the system and that O2●-played a minor role. This was further confirmed by the results of electron paramagnetic resonance measurements and salicylic acid hydroxylationanalysis by high performance liquid chromatography(HPLC). PCE degradation decreased significantly with the addition of isopropanol, a strong HO● scavenger, supporting the hypothesis that HO● was primarily responsible for PCE degradation. It should be noted that the release of Cl- was slightly delayed in the first 20 mins, indicating that intermediate products were produced. However, gas chromatography mass spectrometry (GC/MS) analysis did not detect any chlorinated organic compound except PCE, indicating these intermediates were quickly degraded, which resulted in the complete conversion of PCE to CO2. In conclusion, the use of reducing agents to enhance Fe(II)/Fe(III) catalyzed SPC oxidation appears to be a promising approach for the rapid degradation of organic contaminants in groundwater.

  14. Measuring the volume of cingulate cortex in Chinese normal adults of the Han nationality on the high-resolution MRI

    International Nuclear Information System (INIS)

    age (r=-0.330, -0.324, -0.169, -0.243, P<0.05), though the correlation coefficient is not high. Conclusions: Cingulate cortex volume could be accurately measured on the high-resolution MRI with 3D volume analysis software, which can provide morphological data for the construction of database for Chinese Standard Brain. The results may provide normal range for the diagnosis of the volumetric deficits of cingulate cortex. (authors)

  15. Measuring the volume of the hippocampus in healthy Chinese adults of the Han nationality on the high-resolution MRI

    International Nuclear Information System (INIS)

    Objective: To measure the volume of hippocampal formation (HPF) in healthy Chinese Han adults and provide database for researching on a variety of diseases associated with alteration of hippocampal structure. Methods: This is a clinical multi-center study. One thousand Chinese healthy volunteers (age range=18 to 70) recruited from 15 hospitals were divided into 5 groups, i. e., Group A (age range=18 to 30), B (age range=31 to 40), C (age range =41 to 50), D (age range =51 to 60), and E (age range = 61 to 70). Each group contained 100 males and 100 females. All of the volunteers were scanned by MR using T1 weighted three-dimensional magnetization prepared rapid acquisition gradient echo sequence. The margin of HPF were outlined manually for each side. Using multiple linear regression, relationships between hippocampal volume and sex, age, weight and height were analyzed respectively. Independent two sample t test was used to study the differences between male and female and between left and right. The differences of hippocampal volume among age groups were analyzed by ANOVA. Results: Hippocampal volume for left and right side were (4752±659) and (5032±660) mm3 respectively. The volume of HPF is significant correlated with gender and age, but without relevance to height and weight (left and right r=0.283,0.311, F=30.127,37.050,P3 respectively for men, and (4647±624) and (4904±630) mm3 for women. The right hippocampal volume was larger than the left (t=7.030,6.696, P3 respectively, while the volumes of the fight hippocampus were (5340± 647), (5276±582), (5264±620), (5133±661), (4894±699) mm3 respectively. Among age groups, the differences were statistically significant (left and right F=5.737,7.607, P0.05). There was no significant difference of hippocampal among different groups in women (P>0.05). Conclusions: With high-resolution MRI, the volume of the HPF was accurately measured, so as to provide the basic data for research of the hippocampus

  16. Dynamic regional phase synchrony (DRePS): An Instantaneous Measure of Local fMRI Connectivity Within Spatially Clustered Brain Areas.

    Science.gov (United States)

    Omidvarnia, Amir; Pedersen, Mangor; Walz, Jennifer M; Vaughan, David N; Abbott, David F; Jackson, Graeme D

    2016-05-01

    Dynamic functional brain connectivity analysis is a fast expanding field in computational neuroscience research with the promise of elucidating brain network interactions. Sliding temporal window based approaches are commonly used in order to explore dynamic behavior of brain networks in task-free functional magnetic resonance imaging (fMRI) data. However, the low effective temporal resolution of sliding window methods fail to capture the full dynamics of brain activity at each time point. These also require subjective decisions regarding window size and window overlap. In this study, we introduce dynamic regional phase synchrony (DRePS), a novel analysis approach that measures mean local instantaneous phase coherence within adjacent fMRI voxels. We evaluate the DRePS framework on simulated data showing that the proposed measure is able to estimate synchrony at higher temporal resolution than sliding windows of local connectivity. We applied DRePS analysis to task-free fMRI data of 20 control subjects, revealing ultra-slow dynamics of local connectivity in different brain areas. Spatial clustering based on the DRePS feature time series reveals biologically congruent local phase synchrony networks (LPSNs). Taken together, our results demonstrate three main findings. Firstly, DRePS has increased temporal sensitivity compared to sliding window correlation analysis in capturing locally synchronous events. Secondly, DRePS of task-free fMRI reveals ultra-slow fluctuations of ∼0.002-0.02 Hz. Lastly, LPSNs provide plausible spatial information about time-varying brain local phase synchrony. With the DRePS method, we introduce a framework for interrogating brain local connectivity, which can potentially provide biomarkers of human brain function in health and disease. Hum Brain Mapp 37:1970-1985, 2016. © 2016 Wiley Periodicals, Inc. PMID:27019380

  17. Abdominal MRI

    Science.gov (United States)

    ... kidney and ureter Insulinoma Islet of Langerhans tumor Medullary cystic disease Multiple endocrine neoplasia (MEN) I Multiple endocrine neoplasia ( ... kidney and ureter Insulinoma Kidney stones Lymphofollicular ... kidney disease MRI Multiple endocrine neoplasia (MEN) I Multiple endocrine ...

  18. Pediatric MRI

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NIH Study of Normal Brain Development is a longitudinal study using anatomical MRI, diffusion tensor imaging (DTI), and MR spectroscopy (MRS) to map pediatric...

  19. Changes in Cerebral Blood Flow in Presymptomatic Mutation Carriers of Familial Frontotemporal Dementia (FTD-3), Measured with MRI

    DEFF Research Database (Denmark)

    Lunau, Line Andersen; Mouridsen, Kim; Rodell, Anders;

    presymptomatic stage of the disease as indicated by local changes in cerebral blood flow (CBF). Methods: Presymptomatic mutation carriers and first-degree related non-carriers were MRI-scanned with a spin-echo sequence sensitive mainly to CBF in capillaries. CBF images were co-registered to structural T1-images...

  20. Cerebral blood flow measured by arterial-spin labeling MRI: A useful biomarker for characterization of minimal hepatic encephalopathy in patients with cirrhosis

    International Nuclear Information System (INIS)

    Purpose: To investigate the role of arterial-spin labeling (ASL) MRI to non-invasively characterize the patterns of cerebral blood flow (CBF) changes in cirrhotic patients and to assess the potential of ASL MRI to characterize minimal hepatic encephalopathy (MHE). Materials and methods: This study was approved by the local ethics committee, and written informed consent was obtained from all participants. Thirty six cirrhosis patients without overt hepatic encephalopathy (16 MHE patients and 20 non hepatic encephalopathy (non-HE) patients) and 25 controls underwent ASL MRI, and CBF was measured for each subject. One-way ANOCOVA test with age and gender as covariences was used to compare CBF difference among three groups, and post hoc analysis was performed between each two groups. Region-based correlation analysis was applied between Child–Pugh score, venous blood ammonia level, neuropsychological tests and CBF values in cirrhosis patients. Receiver operator characteristic (ROC) analysis was used for assessing CBF measurements in ASL MRI to differentiate MHE from non-HE patients. Results: The gray matter CBF of MHE patients (71.09 ± 11.88 mL min−1 100 g−1) was significantly higher than that of non-HE patients (55.28 ± 12.30 mL min−1 100 g−1, P < 0.01) and controls (52.09 ± 9.27 mL min−1 100 g−1, P < 0.001). Voxel-wise ANOCOVA results showed that CBFs were significantly different among three groups in multiple gray matter areas (P < 0.05, Bonferroni corrected). Post hoc comparisons showed that CBF of these brain regions was increased in MHE patients compared with controls and non-HE patients (P < 0.05, Bonferroni corrected). CBF of the right putamen was of the highest sensitivity (93.8%) and moderate specificity (75.0%) for characterization of MHE when using the cutoff value of 50.57 mL min−1 100 g−1. CBFs in the bilateral median cingulate gyri, left supramarginal gyrus, right angular gyrus, right heschl gyrus and right superior temporal gyrus

  1. Cerebral blood flow measured by arterial-spin labeling MRI: A useful biomarker for characterization of minimal hepatic encephalopathy in patients with cirrhosis

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210016 (China); Zhang, Long Jiang, E-mail: kevinzhlj@163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Zhong, Jianhui [Department of Imaging Sciences, University of Rochester School of Medicine and Dentistry, Box648, 601 Elmwood Avenue, Rochester, NY 14642-8648 (United States); Wang, Ze [Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, 3900 Chestnut St., Philadelphia, PA 19104 (United States); Qi, Rongfeng; Shi, Donghong [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China); Lu, Guang Ming, E-mail: cjr.luguangming@vip.163.com [Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002 (China)

    2013-11-01

    Purpose: To investigate the role of arterial-spin labeling (ASL) MRI to non-invasively characterize the patterns of cerebral blood flow (CBF) changes in cirrhotic patients and to assess the potential of ASL MRI to characterize minimal hepatic encephalopathy (MHE). Materials and methods: This study was approved by the local ethics committee, and written informed consent was obtained from all participants. Thirty six cirrhosis patients without overt hepatic encephalopathy (16 MHE patients and 20 non hepatic encephalopathy (non-HE) patients) and 25 controls underwent ASL MRI, and CBF was measured for each subject. One-way ANOCOVA test with age and gender as covariences was used to compare CBF difference among three groups, and post hoc analysis was performed between each two groups. Region-based correlation analysis was applied between Child–Pugh score, venous blood ammonia level, neuropsychological tests and CBF values in cirrhosis patients. Receiver operator characteristic (ROC) analysis was used for assessing CBF measurements in ASL MRI to differentiate MHE from non-HE patients. Results: The gray matter CBF of MHE patients (71.09 ± 11.88 mL min{sup −1} 100 g{sup −1}) was significantly higher than that of non-HE patients (55.28 ± 12.30 mL min{sup −1} 100 g{sup −1}, P < 0.01) and controls (52.09 ± 9.27 mL min{sup −1} 100 g{sup −1}, P < 0.001). Voxel-wise ANOCOVA results showed that CBFs were significantly different among three groups in multiple gray matter areas (P < 0.05, Bonferroni corrected). Post hoc comparisons showed that CBF of these brain regions was increased in MHE patients compared with controls and non-HE patients (P < 0.05, Bonferroni corrected). CBF of the right putamen was of the highest sensitivity (93.8%) and moderate specificity (75.0%) for characterization of MHE when using the cutoff value of 50.57 mL min{sup −1} 100 g{sup −1}. CBFs in the bilateral median cingulate gyri, left supramarginal gyrus, right angular gyrus, right

  2. Fractionated manganese injections: effects on MRI contrast enhancement and physiological measures in C57BL/6 mice.

    Science.gov (United States)

    Grünecker, Barbara; Kaltwasser, Sebastian F; Peterse, Yorick; Sämann, Philipp G; Schmidt, Mathias V; Wotjak, Carsten T; Czisch, Michael

    2010-10-01

    Manganese-enhanced MRI (MEMRI) is an increasingly used imaging method in animal research, which enables improved T(1)-weighted tissue contrast. Furthermore accumulation of manganese in activated neurons allows visualization of neuronal activity. However, at higher concentrations manganese (Mn2+) exhibits toxic side effects that interfere with the animals' behaviour and well-being. Therefore, when optimizing MEMRI protocols, a compromise has to be found between minimizing side effects and intensifying image contrast. Recently, a low concentrated fractionated Mn2+ application scheme has been proposed as a promising alternative. In this study, we investigated effects of different fractionated Mn2+ dosing schemes on vegetative, behavioural and endocrine markers, and MEMRI signal contrast in C57BL/6N mice. Measurements of the animals' well-being included telemetric monitoring of body temperature and locomotion, control of weight and observation of behavioural parameters during the time course of the injection protocols. Corticosterone levels after Mn2+ application served as endocrine marker of the stress response. We compared three MnCl2  x 4H2O application protocols: 3 times 60 mg/kg with an inter-injection interval of 48 h, six times 30 mg/kg with an inter-injection interval of 48 h, and 8 times 30 mg/kg with an inter-injection interval of 24 h (referred to as 3 x 60/48, 6 x 30/48 and 8 x 30/24, respectively). Both the 6 x 30/48 and the 8 x 30/24 protocols showed attenuated effects on animals' well-being as compared to the 3 x 60/48 scheme. Best MEMRI signal contrast was observed for the 8 x 30/24 protocol. Together, these results argue for a fractionated application scheme such as 30 mg/kg every 24 h for 8 days to provide sufficient MEMRI signal contrast while minimizing toxic side effects and distress. PMID:20878969

  3. The discrepancy between human peripheral nerve chronaxie times as measured using magnetic and electric field stimuli: the relevance to MRI gradient coil safety

    International Nuclear Information System (INIS)

    Peripheral nerve stimulation (PNS) resulting from electric fields induced from the rapidly changing magnetic fields of gradient coils is a concern in MRI. Nerves exposed to either electric fields or changing magnetic fields would be expected to display consistent threshold characteristics, motivating the direct application of electric field exposure criteria from the literature to guide the development of gradient magnetic field exposure criteria for MRI. The consistency of electric and magnetic field exposures was tested by comparing chronaxie times for electric and magnetic PNS curves for 22 healthy human subjects. Electric and magnetic stimulation thresholds were measured for exposure of the forearm using both surface electrodes and a figure-eight magnetic coil, respectively. The average chronaxie times for the electric and magnetic field conditions were 109 ± 11 μs and 651 ± 53 μs (±SE), respectively. We do not propose that these results call into question the basic mechanism, namely that rapidly switched gradient magnetic fields induce electric fields in human tissues, resulting in PNS. However, this result does motivate us to suggest that special care must be taken when using electric field exposure data from the literature to set gradient coil PNS safety standards in MRI.

  4. SU-E-J-236: Audiovisual Biofeedback Improves Breath-Hold Lung Tumor Position Reproducibility Measured with 4D MRI

    International Nuclear Information System (INIS)

    Purpose: Audiovisual biofeedback breath-hold (AVBH) was employed to reproduce tumor position on inhale and exhale breath-holds for 4D tumor information. We hypothesize that lung tumor position will be more consistent using AVBH compared with conventional breath-hold (CBH). Methods: Lung tumor positions were determined for seven lung cancer patients (age: 25 – 74) during to two separate 3T MRI sessions. A breathhold training session was performed prior to the MRI sessions to allow patients to become comfortable with AVBH and their exhale and inhale target positions. CBH and AVBH 4D image datasets were obtained in the first MRI session (pre-treatment) and the second MRI session (midtreatment) within six weeks of the first session. Audio-instruction (MRI: Siemens Skyra) in CBH and verbal-instruction (radiographer) in AVBH were used. A radiation oncologist contoured the lung tumor using Eclipse (Varian Medical Systems); tumor position was quantified as the centroid of the contoured tumor after rigid registration based on vertebral anatomy across two MRI sessions. CBH and AVBH were compared in terms of the reproducibility assessed via (1) the difference between the two exhale positions for the two sessions and the two inhale positions for the sessions. (2) The difference in amplitude (exhale to inhale) between the two sessions. Results: Compared to CBH, AVBH improved the reproducibility of two exhale (or inhale) lung tumor positions relative to each other by 33%, from 6.4±5.3 mm to 4.3±3.0 mm (p=0.005). Compared to CBH, AVBH improved the reproducibility of exhale and inhale amplitude by 66%, from 5.6±5.9 mm to 1.9±1.4 mm (p=0.005). Conclusions: This study demonstrated that audiovisual biofeedback can be utilized for improving the reproducibility of breath-hold lung tumor position. These results are advantageous towards achieving more accurate emerging radiation treatment planning methods, in addition to imaging and treatment modalities utilizing breath

  5. SU-E-J-236: Audiovisual Biofeedback Improves Breath-Hold Lung Tumor Position Reproducibility Measured with 4D MRI

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D; Pollock, S; Keall, P [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, NSW (Australia); Greer, P [School of Mathematical and Physical Sciences, The University of Newcastle, Newcastle, NSW (Australia); Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW (Australia); Lapuz, C; Ludbrook, J [Department of Radiation Oncology, Calvary Mater Newcastle, Newcastle, NSW (Australia); Kim, T [Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, NSW (Australia); Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA (United States)

    2015-06-15

    Purpose: Audiovisual biofeedback breath-hold (AVBH) was employed to reproduce tumor position on inhale and exhale breath-holds for 4D tumor information. We hypothesize that lung tumor position will be more consistent using AVBH compared with conventional breath-hold (CBH). Methods: Lung tumor positions were determined for seven lung cancer patients (age: 25 – 74) during to two separate 3T MRI sessions. A breathhold training session was performed prior to the MRI sessions to allow patients to become comfortable with AVBH and their exhale and inhale target positions. CBH and AVBH 4D image datasets were obtained in the first MRI session (pre-treatment) and the second MRI session (midtreatment) within six weeks of the first session. Audio-instruction (MRI: Siemens Skyra) in CBH and verbal-instruction (radiographer) in AVBH were used. A radiation oncologist contoured the lung tumor using Eclipse (Varian Medical Systems); tumor position was quantified as the centroid of the contoured tumor after rigid registration based on vertebral anatomy across two MRI sessions. CBH and AVBH were compared in terms of the reproducibility assessed via (1) the difference between the two exhale positions for the two sessions and the two inhale positions for the sessions. (2) The difference in amplitude (exhale to inhale) between the two sessions. Results: Compared to CBH, AVBH improved the reproducibility of two exhale (or inhale) lung tumor positions relative to each other by 33%, from 6.4±5.3 mm to 4.3±3.0 mm (p=0.005). Compared to CBH, AVBH improved the reproducibility of exhale and inhale amplitude by 66%, from 5.6±5.9 mm to 1.9±1.4 mm (p=0.005). Conclusions: This study demonstrated that audiovisual biofeedback can be utilized for improving the reproducibility of breath-hold lung tumor position. These results are advantageous towards achieving more accurate emerging radiation treatment planning methods, in addition to imaging and treatment modalities utilizing breath

  6. A reliable measurement for identifying a lumbosacral transitional vertebra with a solid bony bridge on a single-slice midsagittal MRI or plain lateral radiograph.

    Science.gov (United States)

    Farshad, M; Aichmair, A; Hughes, A P; Herzog, R J; Farshad-Amacker, N A

    2013-11-01

    The purpose of this study was to devise a simple but reliable radiological method of identifying a lumbosacral transitional vertebra (LSTV) with a solid bony bridge on sagittal MRI, which could then be applied to a lateral radiograph. The vertical mid-vertebral angle (VMVA) and the vertical anterior vertebral angle (VAVA) of the three most caudal segments of the lumbar spine were measured on MRI and/or on a lateral radiograph in 92 patients with a LSTV and 94 controls, and the differences per segment (Diff-VMVA and Diff-VAVA) were calculated. The Diff-VMVA of the two most caudal vertebrae was significantly higher in the control group (25° (sd 8) than in patients with a LSTV (type 2a+b: 16° (SD 9), type 3a+b: -9° (SD 10), type 4: -5° (SD 7); p < 0.001). A Diff-VMVA of ≤ +10° identified a LSTV with a solid bony bridge (type 3+4) with a sensitivity of 100% and a specificity of 89% on MRI and a sensitivity of 94% and a specificity of 74% on a lateral radiograph. A sensitivity of 100% could be achieved with a cut-off value of 28° for the Diff-VAVA, but with a lower specificity (76%) on MRI than with Diff-VMVA. Using this simple method (Diff-VMVA ≤ +10°), solid bony bridging of the posterior elements of a LSTV, and therefore the first adjacent mobile segment, can be easily identified without the need for additional imaging. PMID:24151275

  7. The effects of cryoablation on renal cell carcinoma perfusion and glomerular filtration rate measured using dynamic contrast-enhanced MRI: A feasibility study

    International Nuclear Information System (INIS)

    Aim: To assess the effect of cryoablation on renal cell carcinoma (RCC) perfusion and single kidney (SK) glomerular filtration rate (GFR) using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Materials and methods: Eighteen patients undergoing percutaneous cryoablation of a solitary RCC between August 2010 and November 2011 were evaluated with DCE-MRI immediately before and 1 month post-cryoablation. DCE-MRI data were acquired with 2 s temporal resolution in a coronal plane during the first pass of a 0.1 mmol/kg bolus dose of Gd-DOTA. Perfusion of the RCC (in ml/min/100 ml tissue) was estimated using a maximum slope technique. An index of SK GFR (SK-GFRi) was assessed using data acquired every 30 s for the following 3 min in the axial plane and analysed using Rutland–Patlak plots. This was compared to the GFR estimated by creatinine clearance (eGFR). Results: Perfusion in the zone of ablation decreased significantly (p<0.001) from a mean of 98.0 ± 37.5 ml/min/100 ml pre-cryoablation to 11.6 ± 4.1 ml/min/100 ml post-cryoablation; a mean decrease of 88.2%. Functional analysis was performed in seventeen patients. eGFR was underestimated by SK-GFRi which decreased significantly in tumour-bearing (–31.7%, p = 0.011), but not in contralateral kidneys (−4.4%, p = 0.14). Conclusion: It is feasible to measure RCC perfusion pre- and post-cryoablation using DCE-MRI. The significant decrease within the zone of ablation suggests that this technique may be useful for assessment of treatment response. Further work is required to address the underestimation of eGFR by SK-GFRi and to validate the perfusion findings

  8. Effects of spin-lock field direction on the quantitative measurement of spin-lattice relaxation time constant in the rotating frame (T1ρ) in a clinical MRI system

    International Nuclear Information System (INIS)

    Purpose: To investigate whether the direction of spin-lock field, either parallel or antiparallel to the rotating magnetization, has any effect on the spin-lock MRI signal and further on the quantitative measurement of T1ρ, in a clinical 3 T MRI system. Methods: The effects of inverted spin-lock field direction were investigated by acquiring a series of spin-lock MRI signals for an American College of Radiology MRI phantom, while the spin-lock field direction was switched between the parallel and antiparallel directions. The acquisition was performed for different spin-locking methods (i.e., for the single- and dual-field spin-locking methods) and for different levels of clinically feasible spin-lock field strength, ranging from 100 to 500 Hz, while the spin-lock duration was varied in the range from 0 to 100 ms. Results: When the spin-lock field was inverted into the antiparallel direction, the rate of MRI signal decay was altered and the T1ρ value, when compared to the value for the parallel field, was clearly different. Different degrees of such direction-dependency were observed for different spin-lock field strengths. In addition, the dependency was much smaller when the parallel and the antiparallel fields are mixed together in the dual-field method. Conclusions: The spin-lock field direction could impact the MRI signal and further the T1ρ measurement in a clinical MRI system

  9. The 6-minute walk test, motor function measure and quantitative thigh muscle MRI in Becker muscular dystrophy: A cross-sectional study.

    Science.gov (United States)

    Fischer, Dirk; Hafner, Patricia; Rubino, Daniela; Schmid, Maurice; Neuhaus, Cornelia; Jung, Hans; Bieri, Oliver; Haas, Tanja; Gloor, Monika; Fischmann, Arne; Bonati, Ulrike

    2016-07-01

    Becker muscular dystrophy (BMD) has an incidence of 1 in 16 000 male births. This cross-sectional study investigated the relation between validated functional scores and quantitative MRI (qMRI) of thigh muscles in 20 ambulatory BMD patients, aged 18.3-60 years (mean 31.2; SD 11.1). Clinical assessments included the motor function measure (MFM) and its subscales, as well as timed function tests such as the 6-minute walk test (6MWT) and the timed 10-m run/walk test. Quantitative MRI of the thigh muscles included the mean fat fraction (MFF) using a 2-point Dixon (2-PD) technique, and transverse relaxation time (T2) measurements. The mean MFM value was 80.4%, SD 9.44 and the D1 subscore 54.5%, SD 19.9. The median 6MWT was 195m, IQR 160-330.2. The median 10-m run/walk test was 7.4 seconds, IQR 6.1-9.3. The mean fat fraction of the thigh muscles was 55.6%, SD 17.4%, mean T2 relaxation times of all muscles: 69.9 ms, SD 14.4. The flexors had the highest MFF and T2 relaxation times, followed by the extensors and the adductors. MFF and global T2 relaxation times were highly negatively correlated with the MFM total, D1-subscore and 6MWT, and positively correlated with the 10 m run/walk test time (p < 0.01). Age was not correlated with MFF, global T2 relaxation time or clinical assessments. Both MFF and T2 measures in the thigh muscle were well correlated with clinical function in BMD and may serve as a surrogate outcome measure in clinical trials. PMID:27209345

  10. Increasing the Spatial Resolution of 3T Carotid MRI Has No Beneficial Effect for Plaque Component Measurement Reproducibility

    OpenAIRE

    van Wijk, Diederik F.; Strang, Aart C.; Duivenvoorden, Raphael; Enklaar, Dirk-Jan F.; Zwinderman, Aeilko H.; van der Geest, Rob J.; Kastelein, John J. P.; Groot, Eric; Stroes, Erik S. G.; Nederveen, Aart J.

    2015-01-01

    Purpose Different in-plane resolutions have been used for carotid 3T MRI. We compared the reproducibility, as well as the within- and between reader variability of high and routinely used spatial resolution in scans of patients with atherosclerotic carotid artery disease. Since no consensus exists about the optimal segmentation method, we analysed all imaging data using two different segmentation methods. Materials and Methods In 31 patient with carotid atherosclerosis a high (0.25 × 0.25 mm2...

  11. The use of the lumbosacral enlargement as an intrinsic imaging biomarker: feasibility of grey matter and white matter cross-sectional area measurements using MRI at 3T.

    Directory of Open Access Journals (Sweden)

    Marios C Yiannakas

    Full Text Available Histopathological studies have demonstrated the involvement of spinal cord grey matter (GM and white matter (WM in several diseases and recent research has suggested the use of magnetic resonance imaging (MRI as a promising tool for in vivo assessment of the upper spinal cord. However, many neurological conditions would benefit from quantitative assessment of tissue integrity at different levels and relatively little work has been done, mainly due to technical challenges associated with imaging the lower spinal cord. In this study, the value of the lumbosacral enlargement (LSE as an intrinsic imaging biomarker was determined by exploring the feasibility of obtaining within it reliable GM and WM cross-sectional area (CSA measurements by means of a commercially available MRI system at 3 tesla (T. 10 healthy volunteers (mean age 27.5 years, 6 female gave written informed consent and high resolution images of the LSE were acquired and analysed using an optimised MRI acquisition and analysis protocol. GM and WM mean CSA measurements were obtained from a 15 mm section at the level of the LSE and the reproducibility of the measurements was determined by means of scan-rescan, intra- and inter-observer assessments. Mean (±SD LSE cross-sectional area (LSE-CSA was 62.3 (±4.1 mm2 and mean (±SD LSE grey matter cross-sectional area (LSE-GM-CSA was 19.8 (±3.3 mm2. The mean scan-rescan, intra- and inter-observer % coefficient of variation (COV for measuring the LSE-CSA were 2%, 2% and 2.5%, respectively and for measuring the LSE-GM-CSA were 7.8%, 8% and 8.6%, respectively. This study has shown that the LSE can be used reliably as an intrinsic imaging biomarker. The method presented here can be potentially extended to study the LSE in the diseased state and could provide a solid foundation for subsequent multi-parametric MRI investigations.

  12. The impact of reliable pre-bolus T1 measurements or a fixed T1 value in the assessment of glioma patients with Dynamic Contrast Enhancing MRI

    DEFF Research Database (Denmark)

    Tietze, Anna; Mouridsen, Kim; Mikkelsen, Irene Klærke

    2015-01-01

    Purpose: Accurate quantification of hemodynamic parameters using Dynamic Contrast Enhanced MRI (DCE) requires a measurement of tissue T1 prior to contrast injection (T1). We evaluate (i) T1 estimation using the variable flip angle (VFA) and the saturation recovery (SR) techniques and (ii) investi......Purpose: Accurate quantification of hemodynamic parameters using Dynamic Contrast Enhanced MRI (DCE) requires a measurement of tissue T1 prior to contrast injection (T1). We evaluate (i) T1 estimation using the variable flip angle (VFA) and the saturation recovery (SR) techniques and (ii...... patients using an equivalence test (p > 0.05 showing significant difference). (ii) Ktrans, CBF, and Vp were calculated in 42 glioma patients using fixed T1 of 1500ms or an individual T1 measured using SR. The areas under the receiver operating characteristic curves (AUC) were used as measure for accuracy...... to differentiate tumor grade. Results: The T1 values obtained by VFA showed larger variation compared to those obtained using SR both in the digital phantom and the human data (p > 0.05). Although a fixed T1 introduced a bias into the DCE calculation, this had only minor impact on the accuracy...

  13. Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    ... Resonance Imaging (MRI) What is an MRI? MRI stands for Magnetic Resonance Imaging. It is an important ... MRI is often used for diagnosis or for monitoring disease. For example, if someone is having severe ...

  14. MRI Safety during Pregnancy

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z MRI Safety During Pregnancy Magnetic resonance imaging (MRI) Illness ... during the exam? Contrast material MRI during pregnancy Magnetic resonance imaging (MRI) If you are pregnant and your doctor ...

  15. Portable MRI

    International Nuclear Information System (INIS)

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  16. Portable MRI

    Energy Technology Data Exchange (ETDEWEB)

    Espy, Michelle A. [Los Alamos National Laboratory

    2012-06-29

    This project proposes to: (1) provide the power of MRI to situations where it presently isn't available; (2) perform the engineering required to move from lab to a functional prototype; and (3) leverage significant existing infrastructure and capability in ultra-low field MRI. The reasons for doing this: (1) MRI is the most powerful tool for imaging soft-tissue (e.g. brain); (2) Billions don't have access due to cost or safety issues; (3) metal will heat/move in high magnetic fields; (4) Millions of cases of traumatic brain injury in US alone; (5) even more of non-traumatic brain injury; (6) (e.g. stroke, infection, chemical exposure); (7) Need for early diagnostic; (8) 'Signature' wound of recent conflicts; (9) 22% of injuries; (10) Implications for post-traumatic stress disorder; and (11) chronic traumatic encephalopathy.

  17. Fetal MRI

    International Nuclear Information System (INIS)

    New, ultrafast sequences have made it possible to obtain MR images of the fetus without maternal sedation or immobilization of the fetus itself. While fetal MRI began as an adjunct to ultrasound, it has now been shown that MRI can provide additional information that may change prognosis, the management of pregnancy, or the treatment of the newborn child. It is of particular value in the assessment of malformations of the central nervous system. The steady development and adaptation of MR-sequences to the needs of fetal imaging has led to new indications that can support prognostic and therapeutic decisions. (orig.)

  18. Fetal MRI

    Energy Technology Data Exchange (ETDEWEB)

    Prayer, D.; Brugger, P.C. [University Hospital of Vienna (Austria). Division of Neuroradiology

    2004-07-01

    New, ultrafast sequences have made it possible to obtain MR images of the fetus without maternal sedation or immobilization of the fetus itself. While fetal MRI began as an adjunct to ultrasound, it has now been shown that MRI can provide additional information that may change prognosis, the management of pregnancy, or the treatment of the newborn child. It is of particular value in the assessment of malformations of the central nervous system. The steady development and adaptation of MR-sequences to the needs of fetal imaging has led to new indications that can support prognostic and therapeutic decisions. (orig.)

  19. Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners

    International Nuclear Information System (INIS)

    The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures. (authors)

  20. Estimating achievable signal-to-noise ratios of MRI transmit-receive coils from radiofrequency power measurements: applications in quality control

    International Nuclear Information System (INIS)

    The inverse relationship between the radiofrequency (RF) power needed to transmit a 90 deg. RF pulse, and the signal-to-noise ratio (SNR) available from a transmit-receive RF coil is well known. The theory is restated and a formula given for the signal-to-noise ratio from water, achievable from a single-shot MRI experiment, in terms of the net forward RF power needed for a rectangular 90 deg. RF pulse of known shape and duration. The result is normalized to a signal bandwidth of 1 Hz and a sample mass of 1 g. The RF power information needed is available on most commercial scanners, as it is used to calculate specific absorption rates for RF tissue heating. The achievable SNR figure will normally be larger that that actually observed, mainly because of receiver noise, but also because of inaccuracies in setting RF pulse angles, and relaxation effects. Phantom experiments were performed on the transmit-receive RF head coil of a commercial MRI system at 0.95 T using a projection method. The measured SNR agreed with that expected from the formula for achievable SNR once a correction was made for the noise figure of the receiving chain. Comparisons of measured SNR figures with those calculated from RF power measurements are expected to be of value in acceptance testing and quality control. (author)

  1. [Abnormal cerebral blood flow distributions during the post-ictal phase of febrile status epilepticus in three pediatric patients measured by arterial spin labeling perfusion MRI].

    Science.gov (United States)

    Hirano, Keiko; Fukuda, Tokiko

    2016-05-01

    The ability to visualize brain perfusion is important for identifying epileptic foci. We present three pediatric cases showing asymmetrical cerebral blood flow (CBF) distributions during the post-ictal phase of febrile status epilepticus measured by arterial spin labeling (ASL) perfusion MRI. During the acute phase, regional CBF measurements in the areas considered including epileptic foci were higher than in the corresponding area of the contralateral hemisphere, though the exact quantitative value varied between cases. We could not identify the correct epileptogenic foci, because those ASL images were taken after the prolonged and extraordinary activation of neurons in the affected area. During the recovery phase, the differences reduced and the average regional CBF measurement was 54.6 ± 6.1 ml/100 g per minute, which was a little less than the number of previous ASL studies. ASL perfusion MRI imaging provides a method for evaluating regional CBF by using magnetically labeled arterial blood water as an endogenous tracer. With this technique, we can repeatedly evaluate both the brain structure and the level of perfusion at the same time. ASL is noninvasive and easily accessible, and therefore it could become a routine tool for assessment of perfusion in daily practice of pediatric neurology. PMID:27349086

  2. Measurement of the weighted peak level for occupational exposure to gradient magnetic fields for 1.5 and 3 Tesla MRI body scanners.

    Science.gov (United States)

    Bonutti, F; Tecchio, M; Maieron, M; Trevisan, D; Negro, C; Calligaris, F

    2016-03-01

    The purpose of this work is to give a contribution to the construction of a comprehensive knowledge of the exposure levels to gradient magnetic fields (GMF) in terms of the weighed peak (WP), especially for 3 Tesla scanners for which there are still few works available in the literature. A new generation probe for the measurement of electromagnetic fields in the range of 1 Hz-400 kHz was used to assess the occupational exposure levels to the GMF for 1.5 and 3.0 Tesla MRI body scanners, using the method of the WP according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) approach. The probe was placed at a height of 1.1 m, close to the MRI scanners, where operators could stay during some medical procedures with particular issues. The measurements were performed for a set of typical acquisition sequences for body (liver) and head exams. The measured values of WP were in compliance with ICNIRP 2010 reference levels for occupational exposures. PMID:25987585

  3. An analysis of the uncertainty and bias in DCE-MRI measurements using the spoiled gradient-recalled echo pulse sequence

    Energy Technology Data Exchange (ETDEWEB)

    Subashi, Ergys [Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710 and Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States); Choudhury, Kingshuk R. [Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27710 (United States); Johnson, G. Allan, E-mail: gjohnson@duke.edu [Center for In Vivo Microscopy, Duke University Medical Center, Durham, North Carolina 27710 (United States); Medical Physics Graduate Program, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Biomedical Engineering, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2014-03-15

    Purpose: The pharmacokinetic parameters derived from dynamic contrast-enhanced (DCE) MRI have been used in more than 100 phase I trials and investigator led studies. A comparison of the absolute values of these quantities requires an estimation of their respective probability distribution function (PDF). The statistical variation of the DCE-MRI measurement is analyzed by considering the fundamental sources of error in the MR signal intensity acquired with the spoiled gradient-echo (SPGR) pulse sequence. Methods: The variance in the SPGR signal intensity arises from quadrature detection and excitation flip angle inconsistency. The noise power was measured in 11 phantoms of contrast agent concentration in the range [0–1] mM (in steps of 0.1 mM) and in onein vivo acquisition of a tumor-bearing mouse. The distribution of the flip angle was determined in a uniform 10 mM CuSO{sub 4} phantom using the spin echo double angle method. The PDF of a wide range of T1 values measured with the varying flip angle (VFA) technique was estimated through numerical simulations of the SPGR equation. The resultant uncertainty in contrast agent concentration was incorporated in the most common model of tracer exchange kinetics and the PDF of the derived pharmacokinetic parameters was studied numerically. Results: The VFA method is an unbiased technique for measuringT1 only in the absence of bias in excitation flip angle. The time-dependent concentration of the contrast agent measured in vivo is within the theoretically predicted uncertainty. The uncertainty in measuring K{sup trans} with SPGR pulse sequences is of the same order, but always higher than, the uncertainty in measuring the pre-injection longitudinal relaxation time (T1{sub 0}). The lowest achievable bias/uncertainty in estimating this parameter is approximately 20%–70% higher than the bias/uncertainty in the measurement of the pre-injection T1 map. The fractional volume parameters derived from the extended Tofts model

  4. An analysis of the uncertainty and bias in DCE-MRI measurements using the spoiled gradient-recalled echo pulse sequence

    International Nuclear Information System (INIS)

    Purpose: The pharmacokinetic parameters derived from dynamic contrast-enhanced (DCE) MRI have been used in more than 100 phase I trials and investigator led studies. A comparison of the absolute values of these quantities requires an estimation of their respective probability distribution function (PDF). The statistical variation of the DCE-MRI measurement is analyzed by considering the fundamental sources of error in the MR signal intensity acquired with the spoiled gradient-echo (SPGR) pulse sequence. Methods: The variance in the SPGR signal intensity arises from quadrature detection and excitation flip angle inconsistency. The noise power was measured in 11 phantoms of contrast agent concentration in the range [0–1] mM (in steps of 0.1 mM) and in onein vivo acquisition of a tumor-bearing mouse. The distribution of the flip angle was determined in a uniform 10 mM CuSO4 phantom using the spin echo double angle method. The PDF of a wide range of T1 values measured with the varying flip angle (VFA) technique was estimated through numerical simulations of the SPGR equation. The resultant uncertainty in contrast agent concentration was incorporated in the most common model of tracer exchange kinetics and the PDF of the derived pharmacokinetic parameters was studied numerically. Results: The VFA method is an unbiased technique for measuringT1 only in the absence of bias in excitation flip angle. The time-dependent concentration of the contrast agent measured in vivo is within the theoretically predicted uncertainty. The uncertainty in measuring Ktrans with SPGR pulse sequences is of the same order, but always higher than, the uncertainty in measuring the pre-injection longitudinal relaxation time (T10). The lowest achievable bias/uncertainty in estimating this parameter is approximately 20%–70% higher than the bias/uncertainty in the measurement of the pre-injection T1 map. The fractional volume parameters derived from the extended Tofts model were found to be

  5. MRI zoo

    DEFF Research Database (Denmark)

    Laustsen, Christoffer

    The basic idea was to use MRI to produce a sequence of 3D gray scale image slices of various animals, subsequentlyimaged with a clinical CT system. For this purpose, these animals were used: toad, lungfish, python snake and a horseshoe crab. Each animal was sacrificed according to standard proced...

  6. Fetal MRI

    International Nuclear Information System (INIS)

    Ultrasonography is the method of choice for prenatal malformation screening, but it does not always provide sufficient information for correct diagnosis or adequate abnormality evaluation. Fetal MRI is increasingly being used to complete sonographic findings. It was initially used for evaluation of cerebral abnormalities but is increasingly being applied to other fetal areas. In vivo investigation of fetal brain maturation has been enhanced by MRI. An adequate analysis of fetal chest and abdomen can be achieved with fast T2-, T1-weighted and diffusion-weighted imaging (DWI). The advantages include the great field of view and the excellent soft tissue contrast. This allows correct diagnosis of congenital diaphragmatic hernia and evaluation of the consequences on pulmonary growth. Other pulmonary malformations, such as cystic adenomatoid malformation, sequestration and brochogenic cysts, can also be easily identified. Renal position can be quickly determined using DWI sequences and renal agenesia can be easily diagnosed with only one sequence. Prenatal MRI is virtually as effective as postnatal examination, dispenses with transport of a potentially very ill newborn, and provides logistic advantages. Therefore, prenatal MRI is useful for adequate postnatal treatment of newborns with malformations. (orig.)

  7. Classification of first-episode schizophrenia patients and healthy subjects by automated MRI measures of regional brain volume and cortical thickness.

    Directory of Open Access Journals (Sweden)

    Yoichiro Takayanagi

    Full Text Available BACKGROUND: Although structural magnetic resonance imaging (MRI studies have repeatedly demonstrated regional brain structural abnormalities in patients with schizophrenia, relatively few MRI-based studies have attempted to distinguish between patients with first-episode schizophrenia and healthy controls. METHOD: Three-dimensional MR images were acquired from 52 (29 males, 23 females first-episode schizophrenia patients and 40 (22 males, 18 females healthy subjects. Multiple brain measures (regional brain volume and cortical thickness were calculated by a fully automated procedure and were used for group comparison and classification by linear discriminant function analysis. RESULTS: Schizophrenia patients showed gray matter volume reductions and cortical thinning in various brain regions predominantly in prefrontal and temporal cortices compared with controls. The classifiers obtained from 66 subjects of the first group successfully assigned 26 subjects of the second group with accuracy above 80%. CONCLUSION: Our results showed that combinations of automated brain measures successfully differentiated first-episode schizophrenia patients from healthy controls. Such neuroimaging approaches may provide objective biological information adjunct to clinical diagnosis of early schizophrenia.

  8. Meniscal T1rho and T2 measured with 3.0T MRI increases directly after running a marathon

    International Nuclear Information System (INIS)

    To prospectively evaluate changes in T1rho and T2 relaxation time in the meniscus using 3.0 T MRI in asymptomatic knees of marathon runners and to compare these findings with those of age-matched healthy subjects. Thirteen marathon runners underwent 3.0 T MRI including T1rho and T2 mapping sequences before, 48-72 h after, and 3 months after competition. Ten controls were examined at baseline and after 3 months. All images were analyzed by two musculoskeletal radiologists identifying and grading cartilage, meniscal, ligamentous. and other knee abnormalities with WORMS scores. Meniscal segmentation was performed to generate T1rho and T2 maps in six compartments. No differences in morphological knee abnormalities were found before and after the marathon. However, all marathon runners showed a significant increase in T1rho and T2 values after competition in all meniscus compartments (p < 0.0001), which may indicate changes in the biochemical composition of meniscal tissue. While T2 values decreased after 3 months T1rho values remained at a high level, indicating persisting changes in the meniscal matrix composition after a marathon. T2 values in menisci have the potential to be used as biomarkers for identifying reversible meniscus matrix changes indicating potential tissue damage. T1rho values need further study, but may be a valuable marker for diagnosing early, degenerative changes in the menisci following exercise. (orig.)

  9. Development of simultaneous measurement techniques for event-related fMRI and EEG and observation of the activation process of P300

    International Nuclear Information System (INIS)

    In this study, techniques to measure electroencephalogram (EEG) and fMRI simultaneously were investigated, from which P300 responses evoked by visual stimuli were examined. Event-related analysis was applied to combine high temporal resolution of EEG with high spatial resolution of fMRI, which may allow estimation of the temporal change of activation of multiple cortical areas. A time scheme of stimulus presentation and MRI scan was designed, considering the temporal delay between the generation of P300 potential and the blood oxygen level dependent (BOLD) response. Three pattern oddball paradigm using standard, target and novel letter stimuli was performed, in which subjects responded to the rare target-letters but not to frequent standard-and rare novel-letters. Noises arising from MR scan and cardio-ballistic artifacts were removed from the raw data of EEG by subtraction of the time-averaged waveforms of those artifacts. Comparing the grand average response of EEG evoked by target events with that evoked by standard events, a significant difference was found in latency range from 280 to 450 ms (P<0.001). This enlarged response to the target corresponded to the late component, id est (i.e.), P3b, of P300. In the group study of BOLD responses, significant activation appeared in the occipital region, the parietal and temporal regions and the prefrontal cortex, some of which showed a laterality of right-hemisphere dominance. Based on the results of EEG topography during the period of P3b response, a temporal progression of the activations from the occipital visual cortex, via the temporoparietal and temporal regions to the prefrontal cortex was estimated. (author)

  10. Battlefield MRI

    Energy Technology Data Exchange (ETDEWEB)

    Espy, Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-06-01

    Magnetic Resonance Imaging is the best method for non-invasive imaging of soft tissue anatomy, saving countless lives each year. It is regarded as the gold standard for diagnosis of mild to moderate traumatic brain injuries. Furthermore, conventional MRI relies on very high, fixed strength magnetic fields (> 1.5 T) with parts-per-million homogeneity, which requires very large and expensive magnets.

  11. Association of the Fractal Dimension of Retinal Arteries and Veins with Quantitative Brain MRI Measures in HIV-Infected and Uninfected Women

    Science.gov (United States)

    Crystal, Howard A.; Holman, Susan; Lui, Yvonne W.; Baird, Alison E.; Yu, Hua; Klein, Ronald; Rojas-Soto, Diana Marcella; Gustafson, Deborah R.; Stebbins, Glenn T.

    2016-01-01

    Objective The fractal dimension of retinal arteries and veins is a measure of the complexity of the vascular tree. We hypothesized that retinal fractal dimension would be associated with brain volume and white matter integrity in HIV-infected women. Design Nested case-control within longitudinal cohort study. Methods Women were recruited from the Brooklyn site of the Women’s Interagency HIV study (WIHS); 34 HIV-infected and 21 HIV-uninfected women with analyzable MRIs and retinal photographs were included. Fractal dimension was determined using the SIVA software program on skeletonized retinal images. The relationship between predictors (retinal vascular measures) and outcomes (quantitative MRI measures) were analyzed with linear regression models. All models included age, intracranial volume, and both arterial and venous fractal dimension. Some models were adjusted for blood pressure, race/ethnicity, and HIV-infection. Results The women were 45.6 ± 7.3 years of age. Higher arterial dimension was associated with larger cortical volumes, but higher venous dimension was associated with smaller cortical volumes. In fully adjusted models, venous dimension was significantly associated with fractional anisotropy (standardized β = -0.41, p = 0.009) and total gray matter volume (β = -0.24, p = 0.03), and arterial dimension with mean diffusivity (β = -0.33,.p = 0.04) and fractional anisotropy (β = 0.34, p = 0.03). HIV-infection was not associated with any retinal or MRI measure. Conclusions Higher venous fractal dimension was associated with smaller cortical volumes and lower fractional anisotropy, whereas higher arterial fractal dimension was associated with the opposite patterns. Longitudinal studies are needed to validate this finding. PMID:27158911

  12. SPM analysis of cerebrovascular reserve capacity after stimulation with acetazolamide measured by Tc-99m ECD SPECT in normal brain MRI patient

    International Nuclear Information System (INIS)

    This study was undertaken to evaluate normal response of acetazolamide in normal individuals, whose brain MRI is normal, using SPM99. In total, 10 Tc- 99m ECD brain SPECT were evaluated retrospectively. The half of the patients were male. Their mean age was 47.1 years old with a range of 33-61 years. They all visited our neurology department to evaluate stroke symptom. Their brain MRI was normal. Rest/acetazolamide brain SPECT was perfomed using Tc-99m ECD and the sequential injection and subtraction method. SPECT was acquired using fanbeam collimators and triple-head gamma camera (MultiSPECT III, Siemens medical systems, Inc. Hoffman Estates, III, USA). Chang's attenuation correction was applied their brain SPECT revealed normal rCBF pattern in visual analysis by two nuclear physician and they were diagnosed clinically normal. Using SPM method, we compared rest brain SPECT images with those of acetazolamide brain SPECT and measured the extent of the area with significant perfusion change (P<0.05) in predefined 34 cerebral regions. Acetazolamide brain SPECT showed no significant decreased region in comparison to rest brain SPECT. Only small portion of left mid temporal gyrus revealed increased rCBF on acetazolamide brain SPECT in comparison to rest brain SPECT. It apperas that there is no significant change in rCBF between rest and acetazolamide brain SPECT using Tc-99m ECD. The small number of this study is limitation of our study

  13. Measuring the volume of temporal lobe in healthy Chinese adults of the Han nationality on the high-resolution MRI

    International Nuclear Information System (INIS)

    Objective: To explore the morphological features of temporal lobe of healthy Chinese Han adults on the high-resolution MRI and provide morphological data of temporal lobe for the construction of database for Chinese Standard Brain. Methods: This is a clinical multi-center study. Three hundred healthy Chinese volunteers (male 150, and female 150) recruited from 15 hospitals were divided equally into five groups according to their age, i.e., 18-30 (Group A), 31-40 (Group B), 41-50 (Group C), 51- 60(Group D), 61-70(Group E). All subjects were scanned using T1WI 3D MPRAGE sequence and volumes of standardized temporal lobe were collected. The bilateral volumes of standardized temporal lobe were compared by variance analysis between male and female subjects and among five age groups. Results: The mean volumes of left and right temporal lobe were (97 126±15 703) mm3 and (97 015 ± 15 545) mm3 respectively for men, and (95 123 ± 14 564) mm3 and (96 423 ± 13 407) mm3 for women. The difference temporal lobe volume between male and female wasn't significant on the same side (F=1.336, 0.127, P= 0.249, 0.722). The left temporal lobe volumes of Group A-E were (93 873±13 351), (95 566± 11 964), (10 1890 ± 14 511), (93 972 ± 14 050) and (95 636 ± 19 864) mm3 respectively, and those on the right side were (93 409 ± 10 984), (98 158 ± 16 392), (102 079 ± 15 112), (95 448 ± 11 123) and (94 658 ± 16 928) mm3. There were significant differences among 5 groups between left and right temporal lobe volume(F=2.940, 3.514, P=0.021, 0.008). Further pairwise comparison revealed that left and right temporal lobe volume in Group C is higher than those of Group A and D (P0.05). Conclusion: High-resolution MRI could offer detailed images and precise morphological data of temporal lobe, which provides morphological data of temporal lobe for the construction of database for Chinese Standard Brain. (authors)

  14. 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 ... 8 MB) Also available in Other Language versions . Magnetic Resonance Imaging (MRI) is a medical imaging procedure for making ...

  15. What Is Chest MRI?

    Science.gov (United States)

    ... from the NHLBI on Twitter. What Is Chest MRI? Chest MRI (magnetic resonance imaging) is a safe, noninvasive test. "Noninvasive" means that ... your chest wall, heart, and blood vessels. Chest MRI uses radio waves, magnets, and a computer to ...

  16. Knee MRI scan

    Science.gov (United States)

    MRI - knee ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ... less anxious. Your provider may suggest an "open" MRI, in which the machine is not as close ...

  17. A Two-State Analysis of ERP Activity Measures and fMRI Activations Relevant to the Detection of Deception

    Science.gov (United States)

    Schillaci, Michael; Vendemia, Jennifer; Green, Eric; Buzan, Robert; Meek, Scott; Phillips, Michelle

    2007-03-01

    A novel analysis approach for high-density event related scalp potential data (ERP) gathered druing various scenarios is presented. We construct energy-density functional clusters using the empirical voltage and power values and extract extrema of these cognitive activity mesaures to assess the temporal dynamics in areas of physiological significance for the detection of deception. These studies indicate that for questions relating to autobiographical knowledge neocortical interaction times are greater for deceptive responses. This finding is reproduced when workload requirements are increased and suggests that a ``neocortical circuit'' involving activity in short-term memory, visual processing, and executive control regions of the cortex is present. Individual and group analyses are given and continuing experiments involving questions where misinformation is used illustrate that early, up-front control may also be present during deceptive repsonses. A comparison of dipole source models with fMRI data collected in our lab confirms that BOLD activation in the ROIs is consistent with our model of deception.

  18. The Compression Flow as a Measure to Estimate the Cognitive Impairment Severity in Resting State fMRI and 18FDG-PET Alzheimer's Disease Connectomes

    Directory of Open Access Journals (Sweden)

    Antonio Giuliano Zippo

    2015-12-01

    Full Text Available The human brain appears organized in compartments characterized by seemingly specific functional purposes on many spatial scales. A complementary functional state binds information from specialized districts to return what is called integrated information. This fundamental network dynamics undergoes to severe disarrays in diverse degenerative conditions such as Alzheimer's Diseases (AD. The AD represents a multifarious syndrome characterized by structural, functional and metabolic landmarks. In particular, in the early stages of AD, adaptive functional modifications of the brain networks mislead initial diagnoses because cognitive abilities may result indiscernible from normal subjects. As a matter of facts, current measures of functional integration fail to catch significant differences among normal, mild cognitive impairment (MCI and even AD subjects. The aim of this work is to introduce a new topological feature called Compression Flow (CF to finely estimate the extent of the functional integration in the brain networks. The method uses a Monte Carlo-like estimation of the information integration flows returning the compression ratio between the size of the injected information and the size of the condensed information within the network. We analyzed the resting state connectomes of 75 subjects of the Alzheimer's Disease Neuroimaging Initiative 2 (ADNI repository. Our analyses are focused on the 18FGD-PET and functional MRI (fMRI acquisitions in several clinical screening conditions. Results indicated that CF effectively discriminate MCI, AD and normal subjects by showing a significant decrease of the functional integration in the AD and MCI brain connectomes. This result did not emerge by using a set of common complex network statistics. Furthermore, CF was best correlated with individual clinical scoring scales. In conclusion, we presented a novel measure to quantify the functional integration that resulted efficient to discriminate

  19. Measuring hepatic functional reserve using low temporal resolution Gd-EOB-DTPA dynamic contrast-enhanced MRI: a preliminary study comparing galactosyl human serum albumin scintigraphy with indocyanine green retention

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kazuhiro; Hashimoto, Tsuyoshi; Araki, Yoichi; Akata, Soichi; Tokuuye, Koichi [Tokyo Medical University, Department of Radiology, Tokyo (Japan); Ledsam, Joseph; Sourbron, Steven [University of Leeds, Division of Medical Physics, Leeds (United Kingdom)

    2014-01-15

    To investigate if tracer kinetic modelling of low temporal resolution dynamic contrast-enhanced (DCE) MRI with Gd-EOB-DTPA could replace technetium-99 m galactosyl human serum albumin (GSA) single positron emission computed tomography (SPECT) and indocyanine green (ICG) retention for the measurement of liver functional reserve. Twenty eight patients awaiting liver resection for various cancers were included in this retrospective study that was approved by the institutional review board. The Gd-EOB-DTPA MRI sequence acquired five images: unenhanced, double arterial phase, portal phase, and 4 min after injection. Intracellular contrast uptake rate (UR) and extracellular volume (Ve) were calculated from DCE-MRI, along with the ratio of GSA radioactivity of liver to heart-plus-liver and per cent of cumulative uptake from 15-16 min (LHL15 and LU15, respectively) from GSA-scintigraphy. ICG retention at 15 min, Child-Pugh cirrhosis score (CPS) and postoperative Inuyama fibrosis criteria were also recorded. Statistical analysis was with Spearman rank correlation analysis. Comparing MRI parameters with the reference methods, significant correlations were obtained for UR and LHL15, LU15, ICG15 (all 0.4-0.6, P < 0.05); UR and CPS (-0.64, P < 0.001); Ve and Inuyama (0.44, P < 0.05). Measures of liver function obtained by routine Gd-EOB-DTPA DCE-MRI with tracer kinetic modelling may provide a suitable method for the evaluation of liver functional reserve. (orig.)

  20. MRI-based measurements of aerosol deposition in the lung of healthy and elastase-treated rats.

    Science.gov (United States)

    Oakes, Jessica M; Breen, Ellen C; Scadeng, Miriam; Tchantchou, Ghislain S; Darquenne, Chantal

    2014-06-15

    Aerosolized drugs are increasingly being used to treat chronic lung diseases or to deliver therapeutics systemically through the lung. The influence of disease, such as emphysema, on particle deposition is not fully understood. With the use of magnetic resonance imaging (MRI), the deposition pattern of iron oxide particles with a mass median aerodynamic diameter of 1.2 μm was assessed in the lungs of healthy and elastase-treated rats. Tracheostomized rats were ventilated with particles, at a tidal volume of 2.2 ml, and a breathing frequency of 80 breaths/min. Maximum airway pressure was significantly lower in the elastase-treated (Paw = 7.71 ± 1.68 cmH2O) than in the healthy rats (Paw = 10.43 ± 1.02 cmH2O; P perfusion fixed and imaged in a 3T MR scanner. Particle concentration in the different lobes was determined based on a relationship with the MR signal decay rate, R2 (*). Whole lung particle deposition was significantly higher in the elastase-treated rats (CE,part = 3.03 ± 0.61 μm/ml) compared with the healthy rats (CH,part = 1.84 ± 0.35 μm/ml; P < 0.01). However, when particle deposition in each lobe was normalized by total deposition in the lung, there was no difference between the experimental groups. However, the relative dispersion [RD = standard deviation/mean] of R2 (*) was significantly higher in the elastase-treated rats (RDE = 0.32 ± 0.02) compared with the healthy rats (RDH = 0.25 ± 0.02; P < 0.01). These data show that particle deposition is higher and more heterogeneously distributed in emphysematous lungs compared with healthy lungs. PMID:24790020

  1. MRI assessment of relapsed glioblastoma during treatment with bevacizumab: Volumetric measurement of enhanced and FLAIR lesions for evaluation of response and progression—A pilot study

    International Nuclear Information System (INIS)

    Purpose: To develop a magnetic resonance imaging (MRI) metric that is useful for therapy monitoring in patients with relapsed glioblastoma (GBM) during treatment with the antiangiogenic monoclonal antibody bevacizumab (Bev). We evaluated the feasibility of tumour volume measurement with our software tool in clinical routine and tried to establish reproducible and quantitative parameters for surveillance of patients on treatment with antiangiogenic drugs. Materials and methods: In this retrospective institutional pilot study, 18 patients (11 men, 7 women; mean age 53.5) with recurrent GBM received bevacizumab and irinotecan every two weeks as second line therapy. Follow up scans were assessed every two to four months. Data were collected on a 1.5 T MR System (Siemens, Symphony) with the standard head coil using our standardized tumour protocol. Volumetric measurement was performed with a commercial available software stroketool in FLAIR and T1-c imaging with following procedure: Pre-processing involved cutting noise and electing a Gaussian of 3 × 3 to smooth images, selecting a ROI (region of interest) in healthy brain area of the contra lateral side with quantifying the intensity value, adding 20% to this value to define the threshold level. Only values above this threshold are left corresponding to the tumour lesion. For the volumetric measurement the detected tumour area was circuited in all slices and finally summing up all values and multiplied by slice thickness to get the whole volume. Results: With McDonalds criteria progression was indicated in 14 out of 18 patients. In contrast, volumetric measurement showed an increase of contrast enhancement of >25%, defined as threshold for progression, in 11 patients (78%) and in 12 patients (85%) in FLAIR volume, respectively. 6 patients revealed that volumes in MRI increased earlier than the last scan, which was primarily defined as the date of progression with McDonald criteria, changing PFS after re-evaluation of

  2. MRI assessment of relapsed glioblastoma during treatment with bevacizumab: Volumetric measurement of enhanced and FLAIR lesions for evaluation of response and progression—A pilot study

    Energy Technology Data Exchange (ETDEWEB)

    Pichler, Josef, E-mail: josef.pichler@gespag.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria); Pachinger, Corinna, E-mail: pachingercorinna@gmx.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria); Pelz, Manuela, E-mail: mauela.pelz@gespag.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria); Kleiser, Raimund, E-mail: raimund.kleiser@gespag.at [Wagner Jauregg Weg 15, 4020 Linz, Landesnervenklinik Linz (Austria)

    2013-05-15

    Purpose: To develop a magnetic resonance imaging (MRI) metric that is useful for therapy monitoring in patients with relapsed glioblastoma (GBM) during treatment with the antiangiogenic monoclonal antibody bevacizumab (Bev). We evaluated the feasibility of tumour volume measurement with our software tool in clinical routine and tried to establish reproducible and quantitative parameters for surveillance of patients on treatment with antiangiogenic drugs. Materials and methods: In this retrospective institutional pilot study, 18 patients (11 men, 7 women; mean age 53.5) with recurrent GBM received bevacizumab and irinotecan every two weeks as second line therapy. Follow up scans were assessed every two to four months. Data were collected on a 1.5 T MR System (Siemens, Symphony) with the standard head coil using our standardized tumour protocol. Volumetric measurement was performed with a commercial available software stroketool in FLAIR and T1-c imaging with following procedure: Pre-processing involved cutting noise and electing a Gaussian of 3 × 3 to smooth images, selecting a ROI (region of interest) in healthy brain area of the contra lateral side with quantifying the intensity value, adding 20% to this value to define the threshold level. Only values above this threshold are left corresponding to the tumour lesion. For the volumetric measurement the detected tumour area was circuited in all slices and finally summing up all values and multiplied by slice thickness to get the whole volume. Results: With McDonalds criteria progression was indicated in 14 out of 18 patients. In contrast, volumetric measurement showed an increase of contrast enhancement of >25%, defined as threshold for progression, in 11 patients (78%) and in 12 patients (85%) in FLAIR volume, respectively. 6 patients revealed that volumes in MRI increased earlier than the last scan, which was primarily defined as the date of progression with McDonald criteria, changing PFS after re-evaluation of

  3. MRI of cardiovascular malformations

    Energy Technology Data Exchange (ETDEWEB)

    Kastler, Bruno [Centre Hospitalier Univ. Jean Minjoz, Besancon (France); Universite de Franche-Comte, Besancon (FR). Lab. I4S (Health, Innovation, Intervention, Imaging, Engineering); Centre Hospitalier Sherbrooke Univ., PQ (Canada). Dept. of Radiology

    2011-07-01

    MRI is a non-invasive and non-ionizing imaging modality that is perfectly suited for the diagnosis and follow-up of both pediatric and adult congenital heart disease. It provides a large field of view and has the unique ability to depict complex cardiac and vascular anatomy and to measure cardiac function and flow within one examination. MRI is the ideal complement to echocardiography whenever the information provided by the latter is limited. This book has been conceived as a self-teaching manual that will assist qualified radiologists, cardiologists, and pediatricians, as well as those in training. It is richly illustrated with numerous images and drawings that cover all usual and most unusual anomalies. The principal author, Professor Bruno Kastler, is head of radiology at Besancon University Hospital, France and is board certified in both radiology and cardiology. (orig.)

  4. Evaluation of Synthetic MRI for Clinical Use

    OpenAIRE

    Helmersson, Teresa

    2010-01-01

    Conventional Magnetic Resonance Imaging (MRI) is a qualitative method for obtaining images of softtissues in patients. Conventional MRI is the standard method used today and it results in gray-scaleimages in which the different magnetic properties of biological tissues determine the image contrast. However, the magnitude of the measured signal is only relative and therefore not directlycomparable between images. Synthetic MRI is a relatively new technique which can be used to postsynthesizedi...

  5. Right and left ventricular volume measurements in an animal heart model in vitro: first experiences with cardiac MRI at 1.0 T

    International Nuclear Information System (INIS)

    The aim of this study was to determine the accuracy in quantifying right and left ventricular volumes using a 1.0-T system and commercially available, standard equipment. For exact comparison of MRI measurements and real volumes we used an animal heart model ex vivo. Eight pig hearts were explanted and prepared by removal of the atria. Aorta and pulmonary truncus were cannulated. Definable volumes were injected into the ventricles. Magnetic resonance imaging was performed at 1.0 T (Gyroscan T10 NT, Philips, Eindhoven, The Netherlands); sequence: fast field echo-echo planar (multishot EPI); body coil; MR software: Cardiac Application Package (Philips). Statistical analysis correlated the real volumes and MR measurements separately for both ventricles and two investigators (SAS, ANOVA). For both ventricles and both investigators the correlation between real volumes and MR measurements was greater than 0.99. There was no significant systematic false estimation for both ventricles. Magnetic resonance imaging at 1.0 T using standard hardware and software equipment enables the quantification of right and left ventricular volumes with high approximation to the real volumes in vitro. There is a clear restriction in translating these data into a clinical application because under experimental conditions no motion-induced artifacts existed. (orig.)

  6. EEG-fMRI correlation patterns in the presurgical evaluation of focal epilepsy: a comparison with electrocorticographic data and surgical outcome measures.

    Science.gov (United States)

    van Houdt, Petra J; de Munck, Jan C; Leijten, Frans S S; Huiskamp, Geertjan J M; Colon, Albert J; Boon, Paul A J M; Ossenblok, Pauly P W

    2013-07-15

    EEG-correlated functional MRI (EEG-fMRI) visualizes brain regions associated with interictal epileptiform discharges (IEDs). This technique images the epileptiform network, including multifocal, superficial and deeply situated cortical areas. To understand the role of EEG-fMRI in presurgical evaluation, its results should be validated relative to a gold standard. For that purpose, EEG-fMRI data were acquired for a heterogeneous group of surgical candidates (n=16) who were later implanted with subdural grids and strips (ECoG). The EEG-fMRI correlation patterns were systematically compared with brain areas involved in IEDs ECoG, using a semi-automatic analysis method, as well as to the seizure onset zone, resected area, and degree of seizure freedom. In each patient at least one of the EEG-fMRI areas was concordant with an interictally active ECoG area, always including the early onset area of IEDs in the ECoG data. This confirms that EEG-fMRI reflects a pattern of onset and propagation of epileptic activity. At group level, 76% of the BOLD regions that were covered with subdural grids, were concordant with interictally active ECoG electrodes. Due to limited spatial sampling, 51% of the BOLD regions were not covered with electrodes and could, therefore, not be validated. From an ECoG perspective it appeared that 29% of the interictally active ECoG regions were missed by EEG-fMRI and that 68% of the brain regions were correctly identified as inactive with EEG-fMRI. Furthermore, EEG-fMRI areas included the complete seizure onset zone in 83% and resected area in 93% of the data sets. No clear distinction was found between patients with a good or poor surgical outcome: in both patient groups, EEG-fMRI correlation patterns were found that were either focal or widespread. In conclusion, by comparison of EEG-fMRI with interictal invasive EEG over a relatively large patient population we were able to show that the EEG-fMRI correlation patterns are spatially accurate at the

  7. MRI-based noninvasive measurement of intracranial compliance derived from the relationship between transcranial blood and cerebrospinal fluid flows: modeling vs. direct approach

    Science.gov (United States)

    Tain, Rong-Wen; Alperin, Noam

    2008-03-01

    Intracranial compliance (ICC) determines the ability of the intracranial space to accommodate increase in volume (e.g., brain swelling) without a large increase in intracranial pressure (ICP). Therefore, measurement of ICC is potentially important for diagnosis and guiding treatment of related neurological problems. Modeling based approach uses an assumed lumped-parameter model of the craniospinal system (CSS) (e.g., RCL circuit), with either the arterial or the net transcranial blood flow (arterial inflow minus venous outflow) as input and the cranio-spinal cerebrospinal fluid (CSF) flow as output. The phase difference between the output and input is then often used as a measure of ICC However, it is not clear whether there is a predetermined relationship between ICC and the phase difference between these waveforms. A different approach for estimation of ICC has been recently proposed. This approach estimates ICC from the ratio of the intracranial volume and pressure changes that occur naturally with each heartbeat. The current study evaluates the sensitivity of the phase-based and the direct approach to changes in ICC. An RLC circuit model of the cranio-spinal system is used to simulate the cranio-spinal CSF flow for 3 different ICC states using the transcranial blood flows measured by MRI phase contrast from healthy human subjects. The effect of the increase in the ICC on the magnitude and phase response is calculated from the system's transfer function. We observed that within the heart rate frequency range, changes in ICC predominantly affected the amplitude of CSF pulsation and less so the phases. The compliance is then obtained for the different ICC states using the direct approach. The measures of compliance calculated using the direct approach demonstrated the highest sensitivity for changes in ICC. This work explains why phase shift based measure of ICC is less sensitive than amplitude based measures such as the direct approach method.

  8. Magnetic Resonance Imaging (MRI)

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Magnetic Resonance Imaging (MRI) KidsHealth > For Teens > Magnetic Resonance Imaging (MRI) Print A A A Text Size What's ... Exam Safety Getting Your Results What Is MRI? Magnetic resonance imaging (MRI) is a type of safe, painless testing ...

  9. MRI evaluation of vascular dementia

    Institute of Scientific and Technical Information of China (English)

    Yicheng Liu; Hongxing Zhang; Wei Huang; Wenjun Wan; Hongfen Peng

    2006-01-01

    OBJECTTVE: To explain the association between vascular dementia and the cranial MRI manifestations, and recognize the value of cranial MRI in the early diagnosis of vascular dementia and the assessment of disease conditions.DATA SOURCES: Pubmed database was searched to identify articles about the cranial MRI manifestations of patients with vascular dementia published in English from January 1992 to June 2006 by using the key words of "MRI, vascular dementia". Others were collected by searching the name of journals and title of articles in the Chinese full-text journal database.STUDY SELECTTON: The collected articles were primarily checked, those correlated with the cranial MRI manifestations of patients with vascular dementia were selected, while the obviously irrelative ones were excluded, and the rest were retrieved manually, the full-texts were searched.DATA EXTRACTION: Totally 255 articles were collected, 41 of them were involved, and the other 214 were excluded.DATA SYNTHESIS: MRI can be taken as one of the effective methods for the early diagnosis and disease evaluation of vascular dementia. White matter lesions are the important risk factors of vascular dementia.Vascular dementia is accompanied by the atrophy of related brain sites, but further confirmation is needed to investigate whether there is significant difference. MRI can be used to quantitatively investigate the infarcted sites and sizes of patients with vascular dementia after infarction, but there is still lack of systematic investigation on the association of the infarcted sites and sizes with the cognitive function of patients with vascular dementia.CONCLUSTON: Cranial MRI can detect the symptoms of vascular dementia at early period, so that corresponding measures can be adopted to prevent and treat vascular dementia in time.

  10. MRI of restrictive cardiomyopathy

    International Nuclear Information System (INIS)

    Objective: To evaluate the diagnostic value of MRI in combination of delayed gadolinium-enhanced MR imaging for the identification of restrictive cardiomyopathy (RCM). Methods: One hundred sixteen patients with RCM underwent ECG, thoracic radiography, echocardiography and MRI. The final diagnosis was made on comprehensive evaluation in consideration of patient history, clinical symptoms and imaging appearances. Fifty-five normal subjects were used as the controls. All patients were divided into two groups according to contrast-enhanced MRI patterns: RCM with delayed enhancement (RCM with DE, n=35) and RCM without delayed enhancement (RCM without DE, n=81). Bi-atrial and bi-ventricular size, ventricular septal and left free wall thickness were measured. A paired t-test was used for statistic analysis. Results: Bi-atrial size, right ventricular diastolic diameter (RVDD), ventricular septal and left free wall thickness were significantly larger in RCM patients than in normal subjects (P0.05). Visual observation showed mild mitral regurgitation (50 cases), moderate mitral regurgitation (24 cases ), mild tricuspid regurgitation (32 cases) and severe tricuspid regurgitation (46 cases). Thirty-five RCMs with DE presented diffuse (15 cases) or segmental (20 cases) enhancement. Twelve RCMs with diffuse delayed enhancement showed powdery, enhancement, and 3 showed petaline enhancement. Three cases with powdery enhancement were histologically proven as myocardial amyloidosis. Ventricular septum was the most vulnerable segment in patients with segmental enhancement. Six cases presented subendocardial enhancement that corresponded to apical obliteration, of which one case was confirmed as hypereosinophilia by bone marrow biopsy and the other 14 cases didn't present any regular enhancement. In 81 RCMs without DE, marked bi-atrial dilation, near-normal ventricular chambers and near-normal ventricular thickness were presented. Conclusion: MRI is an excellent imaging modality for

  11. Interobserver agreement of semi-automated and manual measurements of functional MRI metrics of treatment response in hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Purpose: To assess the interobserver agreement in 50 patients with hepatocellular carcinoma (HCC) before and 1 month after intra-arterial therapy (IAT) using two semi-automated methods and a manual approach for the following functional, volumetric and morphologic parameters: (1) apparent diffusion coefficient (ADC), (2) arterial phase enhancement (AE), (3) portal venous phase enhancement (VE), (4) tumor volume, and assessment according to (5) the Response Evaluation Criteria in Solid Tumors (RECIST), and (6) the European Association for the Study of the Liver (EASL). Materials and methods: This HIPAA-compliant retrospective study had institutional review board approval. The requirement for patient informed consent was waived. Tumor ADC, AE, VE, volume, RECIST, and EASL in 50 index lesions was measured by three observers. Interobserver reproducibility was evaluated using intraclass correlation coefficients (ICC). P < 0.05 was considered to indicate a significant difference. Results: Semi-automated volumetric measurements of functional parameters (ADC, AE, and VE) before and after IAT as well as change in tumor ADC, AE, or VE had better interobserver agreement (ICC = 0.830–0.974) compared with manual ROI-based axial measurements (ICC = 0.157–0.799). Semi-automated measurements of tumor volume and size in the axial plane before and after IAT had better interobserver agreement (ICC = 0.854–0.996) compared with manual size measurements (ICC = 0.543–0.596), and interobserver agreement for change in tumor RECIST size was also higher using semi-automated measurements (ICC = 0.655) compared with manual measurements (ICC = 0.169). EASL measurements of tumor enhancement in the axial plane before and after IAT ((ICC = 0.758–0.809), and changes in EASL after IAT (ICC = 0.653) had good interobserver agreement. Conclusion: Semi-automated measurements of functional changes assessed by ADC and VE based on whole-lesion segmentation demonstrated better reproducibility than

  12. Interobserver agreement of semi-automated and manual measurements of functional MRI metrics of treatment response in hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Bonekamp, David; Bonekamp, Susanne; Halappa, Vivek Gowdra; Geschwind, Jean-Francois H.; Eng, John; Corona-Villalobos, Celia Pamela [The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD (United States); Pawlik, Timothy M. [The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD (United States); The Johns Hopkins School of Medicine, Department of Surgery, Oncology, Baltimore, MD (United States); Kamel, Ihab R., E-mail: ikamel@jhmi.edu [The Johns Hopkins School of Medicine, Department of Radiology, Baltimore, MD (United States)

    2014-03-15

    Purpose: To assess the interobserver agreement in 50 patients with hepatocellular carcinoma (HCC) before and 1 month after intra-arterial therapy (IAT) using two semi-automated methods and a manual approach for the following functional, volumetric and morphologic parameters: (1) apparent diffusion coefficient (ADC), (2) arterial phase enhancement (AE), (3) portal venous phase enhancement (VE), (4) tumor volume, and assessment according to (5) the Response Evaluation Criteria in Solid Tumors (RECIST), and (6) the European Association for the Study of the Liver (EASL). Materials and methods: This HIPAA-compliant retrospective study had institutional review board approval. The requirement for patient informed consent was waived. Tumor ADC, AE, VE, volume, RECIST, and EASL in 50 index lesions was measured by three observers. Interobserver reproducibility was evaluated using intraclass correlation coefficients (ICC). P < 0.05 was considered to indicate a significant difference. Results: Semi-automated volumetric measurements of functional parameters (ADC, AE, and VE) before and after IAT as well as change in tumor ADC, AE, or VE had better interobserver agreement (ICC = 0.830–0.974) compared with manual ROI-based axial measurements (ICC = 0.157–0.799). Semi-automated measurements of tumor volume and size in the axial plane before and after IAT had better interobserver agreement (ICC = 0.854–0.996) compared with manual size measurements (ICC = 0.543–0.596), and interobserver agreement for change in tumor RECIST size was also higher using semi-automated measurements (ICC = 0.655) compared with manual measurements (ICC = 0.169). EASL measurements of tumor enhancement in the axial plane before and after IAT ((ICC = 0.758–0.809), and changes in EASL after IAT (ICC = 0.653) had good interobserver agreement. Conclusion: Semi-automated measurements of functional changes assessed by ADC and VE based on whole-lesion segmentation demonstrated better reproducibility than

  13. Quantitative measurement of total cerebral blood flow using 2D phase-contrast MRI and doppler ultrasound

    International Nuclear Information System (INIS)

    To compare of quantitative measurement of the total cerebral blood flow using two-dimensional phase-contrast MR imaging and Doppler ultrasound. In 16 volunteers (mean age, 26 years; mean body weight, 66 kg) without abnormal medical histories, two-dimensional phase-contrast MR imaging was performed at the level of the C2-3 inter vertebral disc for flow measurement of the internal carotid arteries and the vertebral arteries. Volume flow measurements using Doppler ultrasound were also performed at the internal carotid arteries 2cm above the carotid bifurcation, and at the vertebral arteries at the level of the upper pole of the thyroid gland. Flows in the four vessels measured by the two methods were compared using Wilcoxon's correlation analysis and the median score. Total cerebral blood flows were calculated by summing these four vessel flows, and mean values for the 16 volunteers were calculated. Cerebral blood flows measured by 2-D phase-contrast MR imaging and Doppler ultrasounds were 233 and 239 ml/min in the right internal carotid artery, 250 and 248 ml/min in the left internal carotid artery, 62 and 56 ml/min in the right vertebral artery, and 83 and 68 ml/min in the left vertebral artery. Correlation coefficients of the blood flows determined by the two methods were 0.48, 0.54, 0.49, and 0.62 in each vessel, while total cerebral blood flows were 628±68 (range, 517 to 779) ml/min and 612±79 (range, 482 to 804)ml/min, respectively. Total cerebral blood flow was easily measured using 2-D phase-contrast MR imaging and Doppler ultrasound, and the two noninvasive methods can therefore be used clinically for the measurement of total cerebral blood flow

  14. Effect of meal volume and calorie load on postprandial gastric function and emptying: studies under physiological conditions by combined fiber-optic pressure measurement and MRI.

    Science.gov (United States)

    Kwiatek, Monika A; Menne, Dieter; Steingoetter, Andreas; Goetze, Oliver; Forras-Kaufman, Zsofia; Kaufman, Elad; Fruehauf, Heiko; Boesiger, Peter; Fried, Michael; Schwizer, Werner; Fox, Mark R

    2009-11-01

    This study assessed the effects of meal volume (MV) and calorie load (CL) on gastric function. MRI and a minimally invasive fiber-optic recording system (FORS) provided simultaneous measurement of gastric volume and pressure changes during gastric filling and emptying of a liquid nutrient meal in physiological conditions. The gastric response to 12 iso-osmolar MV-CL combinations of a multinutrient drink (MV: 200, 400, 600, 800 ml; CL: 200, 300, 400 kcal) was tested in 16 healthy subjects according to a factorial design. Total gastric volume (TGV) and gastric content volume (GCV = MV + secretion) were measured by MRI during nasogastric meal infusion and gastric emptying over 60 min. Intragastric pressure was assessed at 1 Hz by FORS. The dynamic change in postprandial gastric volumes was described by a validated three-component linear exponential model. The stomach expanded with MV, but the ratio of GCV:MV at t(0) diminished with increasing MV (P TGV followed those of GCV. Intragastric pressure increased with MV, and this effect was augmented further by CL (P = 0.02); however, the absolute pressure rise was <4 mmHg. A further postprandial increase of gastric volumes was observed early on before any subsequent volume decrease. This "early" increase in GCV was greater for smaller than larger MV (P < 0.01), indicating faster initial gastric emptying of larger MV. In contrast, volume change during filling and in the early postprandial period were unaffected by CL. In the later postprandial period, gastric emptying rate continued to be more rapid with high MVs (P < 0.001); however, at any given volume, gastric emptying was slowed by higher CL (P < 0.001). GCV half-emptying time decreased with CL at 18 +/- 6 min for each additional 100-kcal load (P < 0.001). These findings indicate that gastric wall stress (passive strain and active tone) provides the driving force for gastric emptying, but distal resistance to gastric outflow regulates further passage of nutrients. The

  15. Reproductibility of apparent diffusion coefficients measurements in diffusion-weighted MRI of the abdomen with different b values

    International Nuclear Information System (INIS)

    Purpose: To test the reproducibility of apparent diffusion coefficients (ADC) measurements of the normal liver, kidney and spleen parenchyma with different b values. Materials and methods: Eleven healthy volunteers were imaged twice with use of the same protocol. Each DWI was performed with b-factors of 0, 100 and 500 s/mm2. The ADCs were organized according to session (1 or 2), anatomic location and repetition (twice with two different b value per session). The ADC data were analyzed with repeated-measures analysis of variance to demonstrate the influence of anatomic location, session and different b values. The coefficient of variation was calculated for each subject, b value and anatomic location, then analyzed by using repeated-measures analysis of variance. Results: There were significant differences in mean ADCs among the three anatomic locations and with different b values (P .05). The CV values range between 7.3% and 14.7%. There were no significant differences in CV values neither between the two b values nor for the various organ locations (P > .05). Conclusion: Using the same technical parameters, patients and the same observer, CV values range between 7.3% and 14.7%. And we recommend to be careful in examination and comparison of the measured ADC values, below these limits, without knowledge technical parameters that has been used, otherwise differences that are merely because of changes in the measurement technique could be interpreted as differences because of progression of disease or therapy

  16. Optimal location for arterial input function measurements near the middle cerebral artery in first-pass perfusion MRI.

    Science.gov (United States)

    Bleeker, Egbert J W; van Buchem, Mark A; van Osch, Matthias J P

    2009-04-01

    One of the main difficulties in obtaining quantitative perfusion values from dynamic susceptibility contrast-magnetic resonance imaging is a correct arterial input function (AIF) measurement, as partial volume effects can lead to an erroneous shape and amplitude of the AIF. Cerebral blood flow and volume scale linearly with the area under the AIF, but shape changes of the AIF can lead to large, nonlinear errors. Current manual and automated AIF selection procedures do not guarantee the exclusion of partial volume effects from AIF measurements. This study uses a numerical model, validated by phantom experiments, for predicting the optimal location for AIF measurements in the vicinity of the middle cerebral artery (MCA). Three different sequences were investigated and evaluated on a voxel-by-voxel basis by comparison with the ground truth. Subsequently, the predictions were evaluated in an in vivo example. The findings are fourfold: AIF measurements should be performed in voxels completely outside the artery, here a linear relation should be assumed between DeltaR*2 and the concentration contrast agent, the exact optimal location differs per acquisition type, and voxels including a small MCA yield also correct AIF measurements for segmented echo planar imaging when a short echo time was used. PMID:19142193

  17. Measurement of the arterial concentration of Gd-DTPA using MRI: a step toward quantitative perfusion imaging

    DEFF Research Database (Denmark)

    Fritz-Hansen, T; Rostrup, Egill; Larsson, H B; Søndergaard, Lise; Ring, P; Henriksen, O

    1996-01-01

    A noninvasive method using an inversion recovery turbo-FLASH for dynamic measurement of the arterial input function represented by the bolus passage of Gd-DTPA in the descending aorta is presented, and the results are compared with the input function obtained by arterial blood samples. A good...

  18. Dynamic contrast-enhanced quantitative perfusion measurement of the brain using T-1-weighted MRI at 3T

    DEFF Research Database (Denmark)

    Larsson, H.B.W.; Hansen, A.E.; Berg, H.K.;

    2008-01-01

    Purpose: To develop a method for the measurement of brain perfusion based on dynamic contrast-enhanced T-1-weighted MR imaging. Materials and Methods: Dynamic imaging of the first pass of a bolus of a paramagnetic contrast agent was performed using a 3T whole-body magnet and a T-1-weighted fast...... field echo sequence. The input function was obtained from the internal carotid artery. An initial T-1 measurement was performed in order to convert the MR signal to concentration of the contrast agent. Pixelwise and region of interest (ROI)based calculation of cerebral perfusion (CBF) was performed...... using Tikhonov's procedure of deconvolution. Seven patients with acute optic neuritis and two patients with acute stroke were investigated. Results: The mean perfusion value for ROIs in gray matter was 62 mL/100g/min and 21 mL/100g/min in white matter in patients with acute optic neuritis. The perfusion...

  19. Measurement of renal volume using respiratory-gated MRI in subjects without known kidney disease: Intraobserver, interobserver, and interstudy reproducibility

    International Nuclear Information System (INIS)

    Objective: Since renal volume is to be considered in managing renal diseases, a reproducible technique is needed. Our aim was to estimate intraobserver, interobserver, and interstudy reproducibility of renal volume measurement in subjects without known kidney disease using magnetic resonance (MR) imaging. Materials and methods: We studied 20 patients (age range 33–82 years) without known renal disease using 1.5-T MR imaging with a respiratory-gated two-dimensional coronal balanced steady state free precession sequence. Each patient repeated the study after 1 h. Two readers independently segmented the area of both kidneys of the first study, subtracting cysts. After 1 week, the first reader segmented the second study and repeated the segmentation of the first study. The volume of each kidney was obtained by multiplying the renal area on each slice by the slice thickness and summing all the partial volumes. Reproducibility was assessed by Bland-Altman and Wilcoxon statistics. The coefficient of repeatability (CoR) was summed to the absolute value of bias; the ratio between this sum and the mean of the two data sets was used as a measure of variability while its complement to 100% was used as a measure of reproducibility. Results: Acquisition time was 2–3 min. Segmentation time was 20–25 min. Intraobserver variability results in a CoR of 7 ml and in a reproducibility of 95%, interobserver variability 8.8–9.8 ml and 87–88%, interstudy variability 9.8–10.6 ml and 91–93%, respectively. Considering both the effect of observer and the repetition of the study, the reproducibility was 83–87%. Conclusion: Renal volume measurement by MR imaging is highly reproducible.

  20. MRI measurements of normal adult scapholunate joint%健康成人舟月关节间隙的磁共振测量

    Institute of Scientific and Technical Information of China (English)

    梁宗辉; 冯晓源; 陈得昶; 徐文东

    2009-01-01

    目的 探讨健康成人舟月关节间隙的磁共振测量值及其意义.方法 63例健康成人,均为右利手,男38例,女25例,右腕41侧,左腕22侧.年龄19~62岁,平均31.1岁.采用GE1.5T MR扫描仪,行冠状面PDWI、T2*WI扫描和横断面PDWI扫描,分别测量不同序列上舟月关节间隙的数值.分析不同性别、年龄、序列及左右手之间舟月关节测量值之间的差异.结果 健康成人舟月关节间隙的平均测量值:冠状面关节间隙宽度[(2.5852±0.3970)mm,x-±s,下同],关节长度(5.5635±0.8936)mm;横断面关节间隙宽度(2.8794±0.4789)mm,关节长度(10.5683±2.1983)mm.且关节间隙宽度的测量值在不同性别、年龄、序列及左右手之间的差异无统计学意义.结论 MRI能够准确测量健康成人舟月关节间隙,为临床提供可靠的正常参考值数据.%Objective To explore the measurements of seapholunate joint in normal adults with MRI and its clinical significance.Methods Sixty-three normal adults,38 men and 25 women,were involved in the study.They were all right hand dominant.Their ages ranged from 19 to 62 years.with all average of 31.1 years.Forty-one right wrists and 22 left wrists were scanned with GE 1.5T Signa Horizon MR scanner.Coronal T1WI.PDWI,T2*WI and axial PDWI were acquired.The scapholunate joint spaces were measured on all sequences.The measured values of the normal adult scapholunate ioints was statistically analyzed to look at the differences in different gender,different age groups,different sequences and right/left hands.Results The average measurement of the normal adult scapholunate joint space:on coronal plane,the width was(2.5852±0.3970)mm and the length was(5.5635±0.8936)mm;on axial plane,the width was(2.8794±0.4789)mm and the length was(10.5683±2.1983)mm.There were no statistically significant differences of the measurements between different genders,different age groups,different sequences and right/left hands of the scapholunate joint

  1. A double-tuned 1H/23Na dual resonator system for tissue sodium concentration measurements in the rat brain via Na-MRI

    International Nuclear Information System (INIS)

    A method for quantifying the tissue sodium concentration (TSC) in the rat brain from 23Na-MR images was developed. TSC is known to change in a variety of common human diseases and holds considerable potential to contribute to their study; however, its accurate measurement in small laboratory animals has been hindered by the extremely low signal to noise ratio (SNR) in 23Na images. To address this, the design, construction and characterization of a double-tuned 1H/23Na dual resonator system for 1H-guided quantitative 23Na-MRI are described. This system comprises an SNR-optimized surface detector coil for 23Na image acquisition, and a volume resonator producing a highly homogeneous B1 field (23Na resonance frequency. A quantification accuracy of TSC of <10 mM was achieved in Na-images with 1.2 μl voxel resolution acquired in 10 min. The potential of the quantification technique was demonstrated in an in vivo experiment of a rat model of cerebral stroke, where the evolution of the TSC was successfully monitored for 8 h after the stroke was induced.

  2. T2 and T2* measurements of fetal brain oxygenation during hypoxia with MRI at 3T: correlation with fetal arterial blood oxygen saturation

    International Nuclear Information System (INIS)

    The purpose of this prospective study was to determine the oxygen saturation of blood in the fetal brain based on T2 and T2* measurements in a fetal sheep model. Five sheep fetuses were investigated during normoxia and hypoxia by 3T MRI. Multi-echo gradient-echo and turbo-spin-echo sequences were performed on the fetal brain. MR-determined oxygen saturation (MR-sO2) of blood in the fetal brain was calculated based on T2 and T2* values. Fetal arterial blood oxygen saturation (blood-sO2) was measured during the two experimental phases. The slope of MR-sO2 as a function of blood-sO2 was estimated and tested for compatibility using the one-sample t-test. During normoxia, mean values for carotid blood oxygen saturation were 67%, 83 ms for T2*, 202 ms for T2 and 96% for MR-sO2. During hypoxia, arterial blood oxygen saturation, T2* and calculated MR-sO2 decreased to 22%, 64 ms, and 68% respectively. The one-sample t-test revealed the slope to be significantly different from 0(T=5.023, df=4, P=0.007). It is feasible to perform quantitative T2 and T2* measurements in the fetal brain. MR-sO2 and fetal arterial blood oxygen saturation correlated significantly. However, based on these data a reliable quantification of fetal brain tissue oxygenation is not possible. (orig.)

  3. T2 and T2* measurements of fetal brain oxygenation during hypoxia with MRI at 3T: correlation with fetal arterial blood oxygen saturation

    Energy Technology Data Exchange (ETDEWEB)

    Wedegaertner, Ulrike; Adam, Gerhard [Universitaetsklinikum Hamburg-Eppendorf, Department of Diagnostic and Interventional Radiology, Hamburg (Germany); Kooijman, Hendrik [Philips Medical Systems, Best (Netherlands); Andreas, Thomas; Beindorff, Nicola; Hecher, Kurt [University Hospital Hamburg-Eppendorf, Department of Obstetrics and Prenatal Medicine, Hamburg (Germany)

    2010-01-15

    The purpose of this prospective study was to determine the oxygen saturation of blood in the fetal brain based on T2 and T2* measurements in a fetal sheep model. Five sheep fetuses were investigated during normoxia and hypoxia by 3T MRI. Multi-echo gradient-echo and turbo-spin-echo sequences were performed on the fetal brain. MR-determined oxygen saturation (MR-sO{sub 2}) of blood in the fetal brain was calculated based on T2 and T2* values. Fetal arterial blood oxygen saturation (blood-sO{sub 2}) was measured during the two experimental phases. The slope of MR-sO{sub 2} as a function of blood-sO{sub 2} was estimated and tested for compatibility using the one-sample t-test. During normoxia, mean values for carotid blood oxygen saturation were 67%, 83 ms for T2*, 202 ms for T2 and 96% for MR-sO{sub 2}. During hypoxia, arterial blood oxygen saturation, T2* and calculated MR-sO{sub 2} decreased to 22%, 64 ms, and 68% respectively. The one-sample t-test revealed the slope to be significantly different from 0(T=5.023, df=4, P=0.007). It is feasible to perform quantitative T2 and T2* measurements in the fetal brain. MR-sO{sub 2} and fetal arterial blood oxygen saturation correlated significantly. However, based on these data a reliable quantification of fetal brain tissue oxygenation is not possible. (orig.)

  4. In vivo MRI measurement of fetal blood oxygen saturation in cardiac ventricles of fetal sheep: a feasibility study.

    Science.gov (United States)

    Wedegärtner, Ulrike; Kooijman, Hendrik; Yamamura, Jin; Frisch, Michael; Weber, Christoph; Buchert, Ralph; Huff, Anna; Hecher, Kurt; Adam, Gerhard

    2010-07-01

    The purpose of this study was to assess the feasibility to determine fetal blood oxygen saturation (sO(2)) with T(2)-weighted MR sequences using a fetal sheep model. T(2) measurements were performed on a 1.5-T scanner using a T(2) preparation pulse in combination with a three-dimensional balanced steady-state free precession sequence repeated at different echo times. Eight sheep fetuses were examined during a control, hypoxic, and recovery phase to perform T(2)-weighted scans of the fetal blood in the heart. Signal intensities in the left and right ventricle were measured to calculate the MR blood sO(2). During each phase, fetal carotid artery sO(2) was directly measured and correlated with MR sO(2). A Bland-Altman plot was performed. Fetal carotid artery sO(2) was 69% sO(2) during control, 16% sO(2) during hypoxemia, and 67% sO(2) during recovery. Mean values of the MR sO(2) were 49% sO(2) and 40% sO(2) for control, 6% sO(2) and 3% sO(2) for hypoxemia, and 51% sO(2) and 43% sO(2) for recovery in left ventricle and right ventricle, respectively. Mean values of fetal carotid artery sO(2) and MR sO(2) were highly correlated (left ventricle: r = 0.87, right ventricle: r = 0.89). According to the Bland-Altman plot, MR sO(2) was lower compared to fetal carotid artery sO(2) (left ventricle: 15%, right ventricle: 20%). Based on our preliminary results, it seems to be possible to assess fetal sO(2) with MR oximetry. PMID:20572133

  5. Presymptomatic cerebral blood flow changes in CHMP2B mutation carriers of familial frontotemporal dementia (FTD-3), measured with MRI

    DEFF Research Database (Denmark)

    Lunau, Line Andersen; Mouridsen, Kim; Rodell, Anders;

    2012-01-01

    OBJECTIVES: To assess functional changes measured by cerebral blood flow (CBF) in the presymptomatic stage of frontotemporal dementia linked to chromosome 3 (FTD-3) caused by a truncating mutation in CHMP2B. DESIGN: Case-control study. SETTING: A memory clinic and tertiary referrals centre for......1 images. Perfusion data were then extracted from seven regions-of-interest, normalised to white matter and statistically compared between carriers and non-carriers. RESULTS: For SE, contrasts between carriers and non-carriers showed significant differences in temporal, occipital and parietal lobes...

  6. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 5: an international multicenter reliability study using computerized MRI erosion volume measurements

    DEFF Research Database (Denmark)

    Bird, P; Ejbjerg, B; McQueen, F; Østergaard, Mikkel; Lassere, M; Edmonds, J

    2003-01-01

    patients with RA. Intra-reader and inter-occasion reliability was also assessed, and different slice thicknesses were compared in terms of erosion volume estimation. A 3 mm slice thickness 3D gradient-echo sequence followed by a 1 mm sequence was performed at baseline and repeated within 24 h with...... volume method was calculated, as well as the inter-occasion reliability, by comparing results from each reader from baseline to the followup scan. One reader performed repeat volume measurements on 5 patients to assess the intra-reader reliability. Five patients were included in the study. Expressed in...... terms of intraclass correlation coefficients (ICC), the inter-reader and inter-occasion reliability of the volume method were comparable to the existing OMERACT scoring system, but large systematic differences in volume estimations were found between readers. The intra-reader reliability was excellent...

  7. Mid-sagittal plane and mid-sagittal surface optimization in brain MRI using a local symmetry measure

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Skoglund, Karl; Ryberg, Charlotte

    2005-01-01

    This paper describes methods for automatic localization of the mid-sagittal plane (MSP) and mid-sagittal surface (MSS). The data used is a subset of the Leukoaraiosis And DISability (LADIS) study consisting of three-dimensional magnetic resonance brain data from 62 elderly subjects (age 66 to 84...... years). Traditionally, the mid-sagittal plane is localized by global measures. However, this approach fails when the partitioning plane between the brain hemispheres does not coincide with the symmetry plane of the head. We instead propose to use a sparse set of profiles in the plane normal direction...... the name, the mid-sagittal plane is not always planar, but a curved surface resulting in poor partitioning of the brain hemispheres. To account for this, this paper also investigates an optimization strategy which fits a thin-plate spline surface to the brain data using a robust least median of...

  8. Computer-aided method for automated selection of optimal imaging plane for measurement of total cerebral blood flow by MRI

    Science.gov (United States)

    Teng, Pang-yu; Bagci, Ahmet Murat; Alperin, Noam

    2009-02-01

    A computer-aided method for finding an optimal imaging plane for simultaneous measurement of the arterial blood inflow through the 4 vessels leading blood to the brain by phase contrast magnetic resonance imaging is presented. The method performance is compared with manual selection by two observers. The skeletons of the 4 vessels for which centerlines are generated are first extracted. Then, a global direction of the relatively less curved internal carotid arteries is calculated to determine the main flow direction. This is then used as a reference direction to identify segments of the vertebral arteries that strongly deviates from the main flow direction. These segments are then used to identify anatomical landmarks for improved consistency of the imaging plane selection. An optimal imaging plane is then identified by finding a plane with the smallest error value, which is defined as the sum of the angles between the plane's normal and the vessel centerline's direction at the location of the intersections. Error values obtained using the automated and the manual methods were then compared using 9 magnetic resonance angiography (MRA) data sets. The automated method considerably outperformed the manual selection. The mean error value with the automated method was significantly lower than the manual method, 0.09+/-0.07 vs. 0.53+/-0.45, respectively (p<.0001, Student's t-test). Reproducibility of repeated measurements was analyzed using Bland and Altman's test, the mean 95% limits of agreements for the automated and manual method were 0.01~0.02 and 0.43~0.55 respectively.

  9. 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 does ... What is MRI and how does it work? Magnetic resonance imaging, or MRI, is a way of obtaining very ...

  10. Apparent diffusion coefficient measurements of bilateral kidneys at 3 T MRI: Effects of age, gender, and laterality in healthy adults

    International Nuclear Information System (INIS)

    Aim: To investigate the effects of age and gender on apparent diffusion coefficient (ADC) measurements of bilateral kidneys at 3 T MRI, and compare the ADC values of left and right kidneys. Materials and methods: In all, 137 healthy participants (mean age 42.8 ± 14.7 years; age range 16–75 years) comprising 68 male and 69 female participants were enrolled. Three Tesla echo-planar diffusion-weighted imaging (DWI) of bilateral kidneys was performed and ADC values were measured in the cortex, medulla, and whole parenchyma. Pearson correlation analysis and linear regression were performed to determine the associations between the ADC values in each region and age. Effects of age and gender on ADC values were analysed using two-factor analysis of variance (ANOVA). The paired-samples t-test was established to compare the ADC values between left and right kidneys. Results: ADC values were significantly higher in the young group (≤50 years) than in the old group (>50 years), and correlated inversely with the age in all regions. Male participants had higher ADC values than female participants in all regions except left medulla. Two-factor ANOVA of age × gender showed no significant interactions between the variables age and gender were found. No significant differences in ADC values between left and right kidneys were observed. Conclusion: Renal ADC values are age- and gender-dependent, and show no significant difference between left and right kidneys. Age- and gender-related effects should be taken into consideration in future renal DWI studies when using normal ADC values from health controls. - Highlights: • Renal apparent diffusion coefficient (ADC) values decrease with ageing. • Men tend to have higher renal ADC values than women. • Bilateral kidneys seem to have no significantly different ADC values

  11. Interventional MRI: update

    Energy Technology Data Exchange (ETDEWEB)

    Lufkin, R.B. [Department of Radiology, University of California Los Angeles, School of Medicine, 10 833 Le Comte Avenue, Los Angeles, CA 90024-1721 (United States); Gronemeyer, D.H.W.; Seibel, R.M.M. [Institute of Diagnostic and Interventional Radiology, Medical Computerscience, University Witten/Herdecke (Germany)

    1997-12-31

    Interventional MRI is in its early stages of development. Nevertheless, the design of new interventional MRI scanners that allow maximum direct access to the patient combined with the development of new interventional MRI pulse sequences and localization systems, means that the archetypal operating rooms of the 21st century may well contain dedicated interventional MRI units for combined radiological and surgical procedures. The present article looks at the state of interventional MRI today and looks ahead to what may be forthcoming in the not-too-distant future. After briefly discussing the instrumentation necessary for practical interventional MRI, the article will go on to describe a number of different approaches to, and clinical applications for, interventional MRI. The use of MRI in guiding and controlling tumor ablation, aspiration cytology and surgical biopsy of different body parts is described. (orig.) With 13 figs., 1 tab., 114 refs.

  12. Abdominal MRI scan

    Science.gov (United States)

    Nuclear magnetic resonance - abdomen; NMR - abdomen; Magnetic resonance imaging - abdomen; MRI of the abdomen ... radiologist see certain areas more clearly. During the MRI, the person who operates the machine will watch ...

  13. Changes in brain connectivity related to the treatment of depression measured through fMRI: a systematic review

    Science.gov (United States)

    Gudayol-Ferré, Esteve; Peró-Cebollero, Maribel; González-Garrido, Andrés A.; Guàrdia-Olmos, Joan

    2015-01-01

    Depression is a mental illness that presents alterations in brain connectivity in the Default Mode Network (DMN), the Affective Network (AN) and other cortical-limbic networks, and the Cognitive Control Network (CCN), among others. In recent years the interest in the possible effect of the different antidepressant treatments on functional connectivity has increased substantially. The goal of this paper is to conduct a systematic review of the studies on the relationship between the treatment of depression and brain connectivity. Nineteen studies were found in a systematic review on this topic. In all of them, there was improvement of the clinical symptoms after antidepressant treatment. In 18 out of the 19 studies, clinical improvement was associated to changes in brain connectivity. It seems that both DMN and the connectivity between cortical and limbic structures consistently changes after antidepressant treatment. However, the current evidence does not allow us to assure that the treatment of depression leads to changes in the CCN. In this regard, some papers report a positive correlation between changes in brain connectivity and improvement of depressive symptomatology, particularly when they measure cortical-limbic connectivity, whereas the changes in DMN do not significantly correlate with clinical improvement. Finally, some papers suggest that changes in connectivity after antidepressant treatment might be partly related to the mechanisms of action of the treatment administered. This effect has been observed in two studies with stimulation treatment (one with rTMS and one with ECT), and in two papers that administered three different pharmacological treatments. Our review allows us to make a series of recommendations that might guide future researchers exploring the effect of anti-depression treatments on brain connectivity. PMID:26578927

  14. Multimodal assessments of the hippocampal formation in schizophrenia and bipolar disorder: Evidences from neurobehavioral measures and functional and structural MRI

    Directory of Open Access Journals (Sweden)

    Christian Knöchel

    2014-01-01

    Full Text Available A potential clinical and etiological overlap between schizophrenia (SZ and bipolar disorder (BD has long been a subject of discussion. Imaging studies imply functional and structural alterations of the hippocampus in both diseases. Thus, imaging this core memory region could provide insight into the pathophysiology of these disorders and the associated cognitive deficits. To examine possible shared alterations in the hippocampus, we conducted a multi-modal assessment, including functional and structural imaging as well as neurobehavioral measures of memory performance in BD and SZ patients compared with healthy controls. We assessed episodic memory performance, using tests of verbal and visual learning (HVLT, BVMT in three groups of participants: BD patients (n = 21, SZ patients (n = 21 and matched (age, gender, education healthy control subjects (n = 21. In addition, we examined hippocampal resting state functional connectivity, hippocampal volume using voxel-based morphometry (VBM and fibre integrity of hippocampal connections using diffusion tensor imaging (DTI. We found memory deficits, changes in functional connectivity within the hippocampal network as well as volumetric reductions and altered white matter fibre integrity across patient groups in comparison with controls. However, SZ patients when directly compared with BD patients were more severely affected in several of the assessed parameters (verbal learning, left hippocampal volumes, mean diffusivity of bilateral cingulum and right uncinated fasciculus. The results of our study suggest a graded expression of verbal learning deficits accompanied by structural alterations within the hippocampus in BD patients and SZ patients, with SZ patients being more strongly affected. Our findings imply that these two disorders may share some common pathophysiological mechanisms. The results could thus help to further advance and integrate current pathophysiological models of SZ and BD.

  15. Measuring the volume of insula in healthy Chinese adults of the Han nationality on the high-resolution MRI

    International Nuclear Information System (INIS)

    Objective: To explore the normal range of the insula volume of Chinese adults of the Hah nationality and its relationship with age, which provide morphological data for the construction of database for Chinese Standard Brain. Methods: This is a clinical multi-center study. One thousand Chinese healthy volunteers (age range = 18 to 70) recruited from 16 hospitals were divided into 5 groups, i.e., Group A (age range =18 to 30), B (age range =31 to 40), C (age range =41 to 50), D (age range = 51 to 60), and E (age range = 61 to 70). Each group contained 100 males and 100 females. All of the volunteers were scanned by MR using T1 weighted three-dimensional magnetization prepared rapid acquisition gradient echo sequence. After three dimension data reconstruction, the volumes of bilateral insula were manually measured. The volume of bilateral insula were compared by paired sample t test. The insula volumes were compared between male and female by independent sample t test, and the differences among 5 age groups were compared by one-way ANNOVA. The relationship between the volumes of insula and age, sex or cerebral volume were analyzed using bivariate correlation, respectively. Results: The left and right side volume of insula before standarized were (7764 ± 1165) and (7387 ± 1128) mm3 respectively, after standarized were (8413 ± 1201) and (7871 ± 1140) mm3 respectively. The left insula volume were significant larger than that of fight (t=-10.565, -16.014, P3 for male, and (7393 ± 1022) mm3 and (7050 ± 1038) mm for female. The left and right insula volumes for male were larger than the female's (t=10.934,9.945,P3, female were (8043± 1054) and (7515 ± 1091 ) mm3, the left and right insula volume of male were larger than the female's(t=4.858,4.632,P3 respectively, the right were (8028 ± 1156), (7636 ± 1075), (7294 ± 986) (7249 ± 1068), (6717 ± 916) mm3 respectively, there were significant differences among 5 groups between left and right insula volume (F= -0

  16. MRI in cranial tuberculosis

    Energy Technology Data Exchange (ETDEWEB)

    Just, M.; Higer, H.P.; Betting, O.; Bockenheimer, S.; Pfannenstiel, P.

    1987-11-01

    A case of multiple intracranial tuberculomas is presented. CT and MRI findings are discussed and compared. MRI showed multiple tuberculomas characterised by the same signal intensity as the surrounding brain parenchyma. Differentiation could be achieved only by the perifocal oedema of the high signal intensity. Changes of the lesions during chemotherapy were monitored by CT and MRI and the results are presented. (orig.)

  17. MRI in cranial tuberculosis.

    Science.gov (United States)

    Just, M; Higer, H P; Betting, O; Bockenheimer, S; Pfannenstiel, P

    1987-11-01

    A case of multiple intracranial tuberculomas is presented. CT and MRI findings are discussed and compared. MRI showed multiple tuberculomas characterised by the same signal intensity as the surrounding brain parenchyma. Differentiation could be achieved only by the perifocal oedema of high signal intensity. Changes of the lesions during chemotherapy were monitored by CT and MRI and the results are presented. PMID:3691545

  18. fMRI Neuroinformatics

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup; Christensen, Mark Schram; Madsen, Kristoffer M.;

    2006-01-01

    Functional magnetic resonance imaging (fMRI) generates vast amounts of data. The handling, processing, and analysis of fMRI data would be inconceivable without computer-based methods. fMRI neuroinformatics is concerned with research, development, and operation of these methods. Reconstruction...

  19. MRI in acute poliomyelitis

    Energy Technology Data Exchange (ETDEWEB)

    Kornreich, L. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Dagan, O. [The Intensive Care Unit, The Schneider Children`s Medical Centre of Israel, Beilinson Medical Campus, Petah Tiqva (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel); Grunebaum, M. [Imaging Department, The Schneider Children`s Medical Centre of Israel, Kaplan Street, Petah Tiqva 49202 (Israel)]|[Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv (Israel)

    1996-05-01

    MRI can be used in the diagnosis of anterior horn infection and for assessing the extent of disease. There are no specific MRI signs to differentiate between the various possible pathogens. This is demonstrated in the present case of poliomyelitis, in which MRI of the spine played an important role in establishing the diagnosis. (orig.). With 1 fig.

  20. Getting an MRI

    Science.gov (United States)

    ... Snowboarding, Skating Crushes What's a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A Text Size en ... Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed pictures of ...

  1. Getting an MRI

    Medline Plus

    Full Text Available ... Snowboarding, Skating Crushes What's a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A Text Size en ... Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed pictures of ...

  2. Getting an MRI

    Medline Plus

    Full Text Available ... Skating Crushes What's a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A Text Size en español Obtención de una resonancia magnética, RM (video) An MRI (magnetic resonance imaging) scan creates detailed ...

  3. Measurement of anteversion of the femoral neck in children by MRI and evaluation by comparison with CT and ultrasound; Messung des femoralen Torsionswinkels von Kindern durch Magnetresonanztomographie im Vergleich mit CT und Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Tomczak, R. [Abt. fuer Roentgendiagnostik, Klinik und Poliklinik fuer Radiologie, Universitaetsklinik Ulm (Germany); Guenther, K. [RKU, Abt. fuer Orthopaedie, Universitaetsklinik Ulm (Germany); Pfeifer, T. [Abt. fuer Roentgendiagnostik, Klinik und Poliklinik fuer Radiologie, Universitaetsklinik Ulm (Germany); Haeberle, H.J. [Abt. fuer Roentgendiagnostik, Klinik und Poliklinik fuer Radiologie, Universitaetsklinik Ulm (Germany); Rieber, A. [Abt. fuer Roentgendiagnostik, Klinik und Poliklinik fuer Radiologie, Universitaetsklinik Ulm (Germany); Danz, B.; Rilinger, N. [Abt. fuer Roentgendiagnostik, Klinik und Poliklinik fuer Radiologie, Universitaetsklinik Ulm (Germany); Friedrich, J.M. [Abt. fuer Roentgendiagnostik, Klinik und Poliklinik fuer Radiologie, Universitaetsklinik Ulm (Germany); Brambs, H.J. [Abt. fuer Roentgendiagnostik, Klinik und Poliklinik fuer Radiologie, Universitaetsklinik Ulm (Germany)

    1995-03-01

    Anteversion of the femoral neck was measured by MRI in 19 children (37 hips) preoperatively before femoral rotation osteotomies. The results of this new technique were compared with values for anteversion obtained by CT and ultrasound. The measurements were performed independently by two observers to determine the correlation between the three different methods and to assess their reliability. It was possible to show a high correlation coefficient (Pearson) between MRI and CT (r=0.77) as well as MRI and sonography (r=0.81). The mean angles obtained by CT (34 degrees, range +5 to +82 degrees) and ultrasound (25.6 degrees, range +10 to +40 degrees) appeared larger than the MRI values (mean angle 23.2 degrees, range 0 to +65 degrees), which can be explained by the different measurement techniques. Mean inter- and intra-variability was low for MRI (r=0.97 and r=0.97) and CT (r=0.99 and r=0.96) but slightly higher for sonography (r=0.88 and r=0.88). MRI is a new reliable and precise method to evaluate femoral anteversion that does not require ionising radiation. (orig./MG) [Deutsch] Die Antetorsion des Schenkelhalses von 19 Kindern (37 Hueften) wurde mit einem MRT-Verfahren gemessen. Die Messergebnisse wurden mit CT- und Ultraschallmessungen verglichen. Alle Untersuchungen wurden unabhaengig von zwei Untersuchern ausgewertet. Es konnte eine hohe Korrelation (Pearson Korrelationskoeffizient) zwischen MRT/CT (r=0,77) und MRT/US (r=0,81) festgestellt werden. Der Mittelwert fuer die gemessenen AT-Winkel lag im CT (34 , +5 bis +82 ) und Ultraschall (25,6 , +10 bis +40 ) deutlich hoeher als in MR (23,2 , 0 bis 65 ), was aus den verwendeten unterschiedlichen Messtechniken erklaert werden kann. Die intra- und interindividuelle Beobachtervariabilitaet war fuer die MRT (r=0,97 und r=0,97) und CT (r=0,99 und r=0,96) niedrig, etwas hoeher fuer die Ultraschalluntersuchung (r=0,88 und r=0,88). (orig./MG)

  4. Diffusion-weighted MRI for tumour volume delineation: comparison with morphological MRI

    International Nuclear Information System (INIS)

    Diffusion-weighted magnetic resonance imaging (dwMRI) is sensitive to tissue microstructure on the cellular level and may therefore help to define biological tumour subvolumes and add complementary information to morphology-based cancer treatment protocols and therapy monitoring. The purpose of this study was therefore to evaluate the potential of dwMRI as compared with morphological MRI (mMRI) for tumour volume delineation using a nude rat human tumour xenograft model. Sixteen tumour-bearing rats (10 H1299, six FaDu) were examined with mMRI (T2-weighted true fast imaging with steady precession (TrueFISP), T1-weighted fast low angle shot (FLASH), T2-weighted dual echo steady state (DESS)) and echo-planar dwMRI in a clinical scanner at 1.5 T. For each method, we compared tumour volume and intra- and inter-observer variability of tumour outer edge delineation (disregarding intra-tumoural structure) as well as tumour signal-to-noise ratio (SNR) and tumour-to-muscle contrast-to-noise ratio (CNR). Tumours were visualised with significantly higher SNR and CNR in dwMRI. Median tumour volumes as measured by dwMRI (3.5 cm3) and mMRI (TrueFISP: 3.3 cm3; FLASH: 3.3 cm3; DESS: 3.2 cm3) were not significantly different and significantly correlated. Related to partial volume effects, the intra- and inter-observer variability of dwMRI (intra/inter: 12%/12%) was larger than for mMRI (TrueFISP: 4%/4%; FLASH: 5%/5%; DESS: 5%/5%). In conclusion, dwMRI allows tumour delineation with overall volume estimation comparable with mMRI approaches but slightly higher observer variability. Thus, besides tumour outline, it may potentially supplement morphology-based therapy planning and monitoring with additional biological information.

  5. Diffusion-weighted MRI for tumour volume delineation: comparison with morphological MRI.

    Science.gov (United States)

    Wolf, G; Schindler, S; Koch, A; Abolmaali, N

    2010-06-01

    Diffusion-weighted magnetic resonance imaging (dwMRI) is sensitive to tissue microstructure on the cellular level and may therefore help to define biological tumour subvolumes and add complementary information to morphology-based cancer treatment protocols and therapy monitoring. The purpose of this study was therefore to evaluate the potential of dwMRI as compared with morphological MRI (mMRI) for tumour volume delineation using a nude rat human tumour xenograft model. Sixteen tumour-bearing rats (10 H1299, six FaDu) were examined with mMRI (T2-weighted true fast imaging with steady precession (TrueFISP), T1-weighted fast low angle shot (FLASH), T2-weighted dual echo steady state (DESS)) and echo-planar dwMRI in a clinical scanner at 1.5 T. For each method, we compared tumour volume and intra- and inter-observer variability of tumour outer edge delineation (disregarding intra-tumoural structure) as well as tumour signal-to-noise ratio (SNR) and tumour-to-muscle contrast-to-noise ratio (CNR). Tumours were visualised with significantly higher SNR and CNR in dwMRI. Median tumour volumes as measured by dwMRI (3.5 cm(3)) and mMRI (TrueFISP: 3.3 cm(3); FLASH: 3.3 cm(3); DESS: 3.2 cm(3)) were not significantly different and significantly correlated. Related to partial volume effects, the intra- and inter-observer variability of dwMRI (intra/inter: 12%/12%) was larger than for mMRI (TrueFISP: 4%/4%; FLASH: 5%/5%; DESS: 5%/5%). In conclusion, dwMRI allows tumour delineation with overall volume estimation comparable with mMRI approaches but slightly higher observer variability. Thus, besides tumour outline, it may potentially supplement morphology-based therapy planning and monitoring with additional biological information. PMID:20598006

  6. A semi-automated method for measuring the evolution of both lumen area and blood flow in carotid from Phase Contrast MRI.

    Science.gov (United States)

    Fasquel, Jean-Baptiste; Lécluse, Aldéric; Cavaro-Ménard, Christine; Willoteaux, Serge

    2015-11-01

    Phase-Contrast (PC) velocimetry Magnetic Resonance Imaging (MRI) is a useful modality to explore cardiovascular pathologies, but requires the automatic segmentation of vessels and the measurement of both lumen area and blood flow evolutions. In this paper, we propose a semi-automated method for extracting lumen boundaries of the carotid artery and compute both lumen area and blood flow evolutions over the cardiac cycle. This method uses narrow band region-based active contours in order to correctly capture the lumen boundary without being corrupted by surrounding structures. This approach is compared to traditional edge-based active contours, considered in related works, which significantly underestimate lumen area and blood flow. Experiments are performed using both a sequence of a homemade phantom and sequences of 20 real carotids, including a comparison with manual segmentation performed by a radiologist expert. Results obtained on the phantom sequence show that the edge-based approach leads to an underestimate of carotid lumen area and related flows of respectively 18.68% and 4.95%. This appears significantly larger than weak errors obtained using the region-based approach (respectively 2.73% and 1.23%). Benefits appear even better on the real sequences. The edge-based approach leads to underestimates of 40.88% for areas and 13.39% for blood flows, compared to limited errors of 7.41% and 4.6% with our method. Experiments also illustrate the high variability and therefore the lack of reliability of manual segmentation. PMID:26453757

  7. Multichannel Compressive Sensing MRI Using Noiselet Encoding

    CERN Document Server

    Pawar, Kamlesh; Zhang, Jingxin

    2014-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI, and presents a method to design the pulse sequence for the noiselet encoding. This novel encoding scheme is combined with the multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. An empirical RIP a...

  8. Once-weekly 22microg subcutaneous IFN-beta-1a in secondary progressive MS: a 3-year follow-up study on brain MRI measurements and serum MMP-9 levels

    DEFF Research Database (Denmark)

    Wu, X; Kuusisto, H; Dastidar, P;

    2007-01-01

    OBJECTIVE: To study the effect of weekly injected subcutaneous interferon (IFN)-beta-1a 22 microg on the extent of brain lesions on magnetic resonance imaging (MRI) and the level of serum matrix metalloproteinase (MMP)-9 in patients with secondary progressive multiple sclerosis (SPMS). SUBJECTS AND...... METHODS: All the 28 Finnish patients participating in the Nordic multicentre trial on the clinical efficacy of weekly IFN-beta-1a (Rebif) 22 microg in SPMS were studied neurologically and by volumetric MRI during a 3-year follow-up. The levels of MMP-9 in serum were measured over the 3-year study. RESULTS......: There was no obvious effect on the number of contrast medium-enhancing lesions, the volume of T1 or T2 lesions or level of serum MMP-9, nor was any effect detected on the relapse rate and the Expanded Disability Status Scale (EDSS). Brain atrophy progression was not affected by the treatment. CONCLUSION...

  9. Simultaneous imaging using Si-PM-based PET and MRI for development of an integrated PET/MRI system

    International Nuclear Information System (INIS)

    The silicon photomultiplier (Si-PM) is a promising photo-detector for PET for use in magnetic resonance imaging (MRI) systems because it has high gain and is insensitive to static magnetic fields. Recently we developed a Si-PM-based depth-of-interaction PET system for small animals and performed simultaneous measurements by combining the Si-PM-based PET and the 0.15 T permanent MRI to test the interferences between the Si-PM-based PET and an MRI. When the Si-PM was inside the MRI and installed around the radio frequency (RF) coil of the MRI, significant noise from the RF sequence of the MRI was observed in the analog signals of the PET detectors. However, we did not observe any artifacts in the PET images; fluctuation increased in the count rate of the Si-PM-based PET system. On the MRI side, there was significant degradation of the signal-to-noise ratio (S/N) in the MRI images compared with those without PET. By applying noise reduction procedures, the degradation of the S/N was reduced. With this condition, simultaneous measurements of a rat brain using a Si-PM-based PET and an MRI were made with some degradation in the MRI images. We conclude that simultaneous measurements are possible using Si-PM-based PET and MRI. (note)

  10. MRI of the pulmonary parenchyma

    International Nuclear Information System (INIS)

    Imaging of the pulmonary parenchyma represents a unique challenge for MRI. Limited signal is caused by low proton density, susceptibility artifacts, and physiological motion (cardiac pulsation, respiration). Recently, further improvements in MRI techniques have widened the potential for investigations of pulmonary parenchymal disease. These include very short echo times, ultrafast turbo-spin-echo acquisitions, projection reconstruction technique, breathhold imaging, ECG triggering, contrast agents (perfusion imaging, aerosols), sodium imaging, hyperpolarized noble gas imaging, and oxygen enhancement. By using widely available techniques, MRI is helpful in the assessment of (a) acute alveolitic processes in chronic infiltrative lung disease, (b) detection and characterization of pulmonary nodules, (c) detection, characterization, and follow-up of pneumonia, (d) differentiation of obstructive atelectasis from non-obstructive atelectasis and infarctions, and (e) measurements of lung water content. Chronic bronchitis, bronchiectasis, and emphysema are not readily assessable by routine MRI techniques. More sophisticated techniques are under investigation for MR imaging of pulmonary ventilation and perfusion. They represent the beginning of functional MR imaging of the lung which will be established in the future. (orig.)

  11. MRI of the pulmonary parenchyma

    Energy Technology Data Exchange (ETDEWEB)

    Kauczor, H.U.; Kreitner, K.F. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Radiologie

    1999-07-01

    Imaging of the pulmonary parenchyma represents a unique challenge for MRI. Limited signal is caused by low proton density, susceptibility artifacts, and physiological motion (cardiac pulsation, respiration). Recently, further improvements in MRI techniques have widened the potential for investigations of pulmonary parenchymal disease. These include very short echo times, ultrafast turbo-spin-echo acquisitions, projection reconstruction technique, breathhold imaging, ECG triggering, contrast agents (perfusion imaging, aerosols), sodium imaging, hyperpolarized noble gas imaging, and oxygen enhancement. By using widely available techniques, MRI is helpful in the assessment of (a) acute alveolitic processes in chronic infiltrative lung disease, (b) detection and characterization of pulmonary nodules, (c) detection, characterization, and follow-up of pneumonia, (d) differentiation of obstructive atelectasis from non-obstructive atelectasis and infarctions, and (e) measurements of lung water content. Chronic bronchitis, bronchiectasis, and emphysema are not readily assessable by routine MRI techniques. More sophisticated techniques are under investigation for MR imaging of pulmonary ventilation and perfusion. They represent the beginning of functional MR imaging of the lung which will be established in the future. (orig.)

  12. MRI in psychiatry

    Energy Technology Data Exchange (ETDEWEB)

    Mulert, Christoph [UKE, Hamburg (Germany). Psychiatry Neuroimaging Branch; Shenton, Martha E. (ed.) [Harvard Medical School, Boston, MA (United States). Dept. of Psychiatry and Radiology

    2014-07-01

    This is the first comprehensive textbook on the use of MRI in psychiatry covering imaging techniques, brain systems and a review of findings in different psychiatric disorders. The book is divided into three sections, the first of which covers in detail all the major MRI-based methodological approaches available today, including fMRI, EEG-fMRI, DTI, and MR spectroscopy. In addition, the role of MRI in imaging genetics and combined brain stimulation and imaging is carefully explained. The second section provides an overview of the different brain systems that are relevant for psychiatric disorders, including the systems for perception, emotion, cognition, and reward. The final part of the book presents the MRI findings that are obtained in all the major psychiatric disorders using the previously discussed techniques. Numerous carefully chosen images support the informative text, making this an ideal reference work for all practitioners and trainees with an interest in this flourishing field.

  13. 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 ... limitations of MRI of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is ...

  14. Abdominal MRI in childhood

    International Nuclear Information System (INIS)

    MRI provides diagnostic information in multiple abdominal diseases in childhood. Additional information to sonographic findings can be achieved in the diagnosis of abdominal malformation as well as in several inflammatory processes. In childhood cancer imaging MRI is essential at the beginning as well as during therapy to assess response to therapy. Because of radiation protection MRI has to replace CT in abdominal imaging in children. Some technical details have to be considered when children are examined. (orig.)

  15. Correlating tumor metabolic progression index measured by serial FDG PET-CT, apparent diffusion coefficient measured by magnetic resonance imaging (MRI) and blood genomics to patient’s outcome in advanced colorectal cancer: the CORIOLAN study

    International Nuclear Information System (INIS)

    Metastatic colorectal cancer (mCRC) may present various behaviours that define different courses of tumor evolution. There is presently no available tool designed to assess tumor aggressiveness, despite the fact that this is considered to have a major impact on patient outcome. CORIOLAN is a single-arm prospective interventional non-therapeutic study aiming mainly to assess the natural tumor metabolic progression index (TMPI) measured by serial FDG PET-CT without any intercurrent antitumor therapy as a prognostic factor for overall survival (OS) in patients with mCRC. Secondary objectives of the study aim to test the TMPI as a prognostic marker for progression-free survival (PFS), to assess the prognostic value of baseline tumor FDG uptake on PFS and OS, to compare TMPI to classical clinico-biological assessment of prognosis, and to test the prognostic value on OS and PFS of MRI-based apparent diffusion coefficient (ADC) and variation of vADC using voxel-based diffusion maps. Additionally, this study intends to identify genomic and epigenetic factors that correlate with progression of tumors and the OS of patients with mCRC. Consequently, this analysis will provide information about the signaling pathways that determine the natural and therapy-free course of the disease. Finally, it would be of great interest to investigate whether in a population of patients with mCRC, for which at present no known effective therapy is available, tumor aggressiveness is related to elevated levels of circulating tumor cells (CTCs) and to patient outcome. Tumor aggressiveness is one of the major determinants of patient outcome in advanced disease. Despite its importance, supported by findings reported in the literature of extreme outcomes for patients with mCRC treated with chemotherapy, no objective tool allows clinicians to base treatment decisions on this factor. The CORIOLAN study will characterize TMPI using FDG-PET-based metabolic imaging of patients with chemorefractory m

  16. 区域生长法在胎儿磁共振羊水量测量中的应用%Application of the Region Growing Method in Measuring the Amniotic Fluid in Fetal MRI

    Institute of Scientific and Technical Information of China (English)

    胡立伟; 薛潋滟; 董素贞; 钟玉敏; 朱铭

    2015-01-01

    目的:探讨磁共振成像中利用区域生长法测量胎儿羊水量的可行性。方法选取26例胎儿的磁共振图像,采用传统方法和区域生长法对胎儿的羊水量进行测量,测量误差值并计算回归线性方程。结果羊水过少时的测量误差为10%~15%,而羊水量正常和过多时的测量误差为1.2%~8%,最后计算得到的回归线性方程为Y=0.975X-9.748。线性方程矫正后的平均羊水量误差仅为2.32%。结论对胎儿进行磁共振检查后,采用区域生长法测量胎儿的羊水量具有操作简单、测量数据真实等优点,可以作为临床对于胎儿羊水量评估的有效手段。%Objective To study the feasibility of the region growing method in measuring the amniotic lfuid in fetal MRI. Methods Altogether 26 foetuses were selected and scanned by MRI. Then, the amniotic lfuid in fetal MRI was measured respectively through the region growing method and the traditional method so as to measure the error value and calculate the linear regression equation. Results The measurement error was 10%to 15%under the conditions of oligohydramnios;while the error was in excess of 1.2%to 8%under the conditions of normality and polyhydramnios. The linear regression equation was calculated as Y=0.975X-9.748. After rectiifcation of the amniotic lfuid value through the linear regression equation, the average error was reduced to only 2.32%. Conclusion The region growing was an easy-to-operate method for precise measurement of the amniotic lfuid after foetuses were scanned by MRI, which should be used as an effective clinical method to measure the fetal amniotic lfuid.

  17. MRI of adrenal masses

    International Nuclear Information System (INIS)

    The diagnostic usefulness of MRI was evaluated on 38 adrenal masses. The most important finding differentiating adenomas from metastases was the size of the tumor and the signal intensity of the mass. Adenomas showed a tendency to be smaller and homogeneous in signal intensity. On MRI with Gd-DTPA adenomas also showed moderate homogeneous enhancement, but metastases were inhomogeneously enhanced. The detectability by MRI was almost comparable with CT. Three cases of small adenomas and hyperplasia 1-1.5 cm in diameter were detectable only with CT. MRI seems to be complementary to CT in the diagnosis of adrenal masses. (author)

  18. MRI assessment program

    International Nuclear Information System (INIS)

    Usage, cost and efficacy data from the MRI Assessment Program to 30 March 1988 is presented, as a continuation of an earlier analysis. Analysis has been performed on data from 8565 examinations relating to 7997 patients at 4 hospitals. MRI was used mainly for examination of the head and spine. Some details of the follow up studies being conducted on selected patients and disease categories are given. A consensus statement is included which summaries the view of the Technical Committee on the potential applications of MRI in Australia. The MRI unit quench incident at Royal Adelaide Hospital is described. Refs., 10 figs., tabs

  19. Demonstration of metabolic and cellular effects of portal vein ligation using multi-modal PET/MRI measurements in healthy rat liver.

    Directory of Open Access Journals (Sweden)

    András Fülöp

    Full Text Available OBJECTIVES: In the early recognition of portal vein ligation (PVL induced tumor progression, positron emission tomography and magnetic resonance imaging (PET/MRI could improve diagnostic accuracy of conventionally used methods. It is unknown how PVL affects metabolic patterns of tumor free hepatic tissues. The aim of this preliminary study is to evaluate the effect of PVL on glucose metabolism, using PET/MRI imaging in healthy rat liver. MATERIALS AND METHODS: Male Wistar rats (n=30 underwent PVL. 2-deoxy-2-(18Ffluoro-D-glucose (FDG PET/MRI imaging (nanoScan PET/MRI and morphological/histological examination were performed before (Day 0 and 1, 2, 3, and 7 days after PVL. Dynamic PET data were collected and the standardized uptake values (SUV for ligated and non-ligated liver lobes were calculated in relation to cardiac left ventricle (SUVVOI/SUVCLV and mean liver SUV (SUVVOI/SUVLiver. RESULTS: PVL induced atrophy of ligated lobes, while non-ligated liver tissue showed compensatory hypertrophy. Dynamic PET scan revealed altered FDG kinetics in both ligated and non-ligated liver lobes. SUVVOI/SUVCLV significantly increased in both groups of lobes, with a maximal value at the 2nd postoperative day and returned near to the baseline 7 days after the ligation. After PVL, ligated liver lobes showed significantly higher tracer uptake compared to the non-ligated lobes (significantly higher SUVVOI/SUVLiver values were observed at postoperative day 1, 2 and 3. The homogenous tracer biodistribution observed before PVL reappeared by 7th postoperative day. CONCLUSION: The observed alterations in FDG uptake dynamics should be taken into account during the assessment of PET data until the PVL induced atrophic and regenerative processes are completed.

  20. Impact of diffusion-weighted MRI-measured initial cerebral infarction volume on clinical outcome in acute stroke patients with middle cerebral artery occlusion treated by thrombolysis

    Energy Technology Data Exchange (ETDEWEB)

    Sanak, Daniel; Bartkova, Andrea; Herzig, Roman; Skoloudik, David; Vlachova, Ivanka; Kanovsky, Petr [University Hospital, Stroke Center, Department of Neurology, Olomouc (Czech Republic); Nosal' , Vladimir; Kurca, Egon [University Hospital, Department of Neurology, Martin (Slovakia); Horak, David; Bucil, Jiri; Burval, Stanislav; Koecher, Martin [University Hospital, Stroke Center, Department of Radiology, Olomouc (Czech Republic); Zelenak, Kamil; Cisarikova, Viera [University Hospital, Department of Radiology, Martin (Slovakia); Zapletalova, Jana [Palacky University Medical School, Department of Biometry and Statistics, Olomouc (Czech Republic)

    2006-09-15

    Magnetic resonance imaging (MRI) may help identify acute stroke patients with a higher potential benefit from thrombolytic therapy. The aim of our study was to assess the correlation between initial cerebral infarct (CI) volume (quantified on diffusion-weighted MRI) and the resulting clinical outcome in acute stroke patients with middle cerebral artery (MCA) (M{sub 1-2} segment) occlusion detected on MRI angiography treated by intravenous/intraarterial thrombolysis. Initial infarct volume (V{sub DWI-I}) was retrospectively compared with neurological deficit evaluated using the NIH stroke scale on admission and 24 h later, and with the 90-day clinical outcome assessed using the modified Rankin scale in a series of 25 consecutive CI patients. The relationship between infarct volume and neurological deficit severity was assessed and, following the establishment of the maximum V{sub DWI-I} still associated with a good clinical outcome, the patients were divided into two groups (V{sub DWI-I} {<=}70 ml and >70 ml). V{sub DWI-I} ranged from 0.7 to 321 ml. The 24-h clinical outcome improved significantly (P=0.0001) in 87% of patients with a V{sub DWI-I} {<=}70 ml (group 1) and deteriorated significantly (P=0.0018) in all patients with a V{sub DWI-I} >70 ml (group 2). The 90-day mortality was 0% in group 1 and 71.5% in group 2. The 90-day clinical outcome was significantly better in group 1 than in group 2 (P=0.026). Clinical outcome could be predicted from initial infarct volume quantified by MRI-DWI in acute CI patients with MCA occlusion treated by intravenous/intraarterial thrombolysis. Patients with a V{sub DWI-I} {<=}70 ml had a significantly better outcome. (orig.)

  1. Visualization of transcoronary ablation of septal hypertrophy in patients with hypertrophic obstructive cardiomyopathy: a comparison between cardiac MRI, invasive measurements and echocardiography

    OpenAIRE

    Sohns, Christian; Sossalla, Samuel; Schmitto, Jan D; Jacobshagen, Claudius; Raab, Björn; Obenauer, Silvia; Maier, Lars S.

    2010-01-01

    Objective Hypertrophic obstructive cardiomyopathy (HOCM) is treated by surgical myectomy or transcoronary ablation of septal hypertrophy (TASH). The aim of this study was to visualize the feasibility, success and short-term results of TASH on the basis of cardiac MRI (CMR) in comparison with cardiac catheterization and echocardiography. Methods In this in vivo study, nine patients with HOCM were treated with TASH. Patients were evaluated by transthoracic echocardiography, invasive cardiac ang...

  2. Hippocampus, caudate nucleus and entorhinal cortex volumetric MRI measurements in discrimination between Alzheimer’s disease, mild cognitive impairment, and normal aging

    OpenAIRE

    Rasha Elshafey; Omar Hassanien; Mohamed Khalil; Mina Rizk Allah; Sameh Saad; Michael Baghdadi; Magdy El Zayady

    2014-01-01

    Background: Structural neuroimaging MR volumetric changes can predict progression of MCI to AD. Early effective treatment of MCI has been shown to delay institutionalization and improve cognition and behavioral symptoms. Aim of the work: To evaluate the role of volumetric MRI to identify a pattern of regional atrophy characteristic in differentiation between Alzheimer’s disease, Mild Cognitive Impairment, and Normal elderly control. Material and methods: The regional ethics committee ap...

  3. On clustering fMRI time series

    DEFF Research Database (Denmark)

    Goutte, Cyril; Toft, Peter Aundal; Rostrup, E.; Nielsen, Finn Årup; Hansen, Lars Kai

    1999-01-01

    indicate whether sets of voxels are activated in a similar way or in different ways. Typically, delays between two activated signals are not identified. In this article, we use clustering methods to detect similarities in activation between voxels. We employ a novel metric that measures the similarity...... between the activation stimulus and the fMRI signal. We present two different clustering algorithms and use them to identify regions of similar activations in an fMRI experiment involving a visual stimulus....

  4. Evaluation of passive cardiomyoplasty using left- and right-ventricular volume measurements by EBCT and MRI in patients with chronic congestive heart failure

    International Nuclear Information System (INIS)

    Purpose: To evaluate the efficacy of passive cardiomyoplasty with the determination of biventricular volumes, global systolic function as well as left-ventricular muscle mass. Materials and Methods: In 19 patients with congestive heart failure of idiopathic or ischemic origin, a polyester mesh-graft was implanted around both ventricles for stabilization and functional support. Before and three months after surgery, 15 patients underwent EBCT and 4 patients with impaired renal function underwent MRI, for the evaluation of the volume and ejection fraction of both ventricles. Results: EBCT demonstrated a decrease from 385 to 310 ml in LV-EDV, from 312 to 242 ml in LV-ESV, from 209 to 160 ml in RV-EDV and from 149 to 87 ml in RV-ESV, and an increase from 20 to 26% in LV-EF and from 37 to 50% in RV-EF as well as a reduction of LV-MM from 300 to 274 g (p < 0.05 each). Similar results were obtained by MRI. Conclusion: Following passive cardiomyoplasty, EBCT and MRI revealed an improvement of the global systolic function as well as a reduction of biventricular volumes and left-ventricular muscle mass. (orig.)

  5. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  6. Magnetic Resonance Imaging (MRI) -- Head

    Science.gov (United States)

    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... medically necessary. MRI may not always distinguish between cancer tissue and fluid, known as edema . MRI typically ...

  7. Multichannel Compressive Sensing MRI Using Noiselet Encoding

    Science.gov (United States)

    Pawar, Kamlesh; Egan, Gary; Zhang, Jingxin

    2015-01-01

    The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP) of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS). In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS) framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding. PMID:25965548

  8. Multichannel compressive sensing MRI using noiselet encoding.

    Directory of Open Access Journals (Sweden)

    Kamlesh Pawar

    Full Text Available The incoherence between measurement and sparsifying transform matrices and the restricted isometry property (RIP of measurement matrix are two of the key factors in determining the performance of compressive sensing (CS. In CS-MRI, the randomly under-sampled Fourier matrix is used as the measurement matrix and the wavelet transform is usually used as sparsifying transform matrix. However, the incoherence between the randomly under-sampled Fourier matrix and the wavelet matrix is not optimal, which can deteriorate the performance of CS-MRI. Using the mathematical result that noiselets are maximally incoherent with wavelets, this paper introduces the noiselet unitary bases as the measurement matrix to improve the incoherence and RIP in CS-MRI. Based on an empirical RIP analysis that compares the multichannel noiselet and multichannel Fourier measurement matrices in CS-MRI, we propose a multichannel compressive sensing (MCS framework to take the advantage of multichannel data acquisition used in MRI scanners. Simulations are presented in the MCS framework to compare the performance of noiselet encoding reconstructions and Fourier encoding reconstructions at different acceleration factors. The comparisons indicate that multichannel noiselet measurement matrix has better RIP than that of its Fourier counterpart, and that noiselet encoded MCS-MRI outperforms Fourier encoded MCS-MRI in preserving image resolution and can achieve higher acceleration factors. To demonstrate the feasibility of the proposed noiselet encoding scheme, a pulse sequences with tailored spatially selective RF excitation pulses was designed and implemented on a 3T scanner to acquire the data in the noiselet domain from a phantom and a human brain. The results indicate that noislet encoding preserves image resolution better than Fouirer encoding.

  9. MRI of Listeria rhombencephalitis

    International Nuclear Information System (INIS)

    A case of Listeria rhombencephalitis in a patient, who was evaluated by MRI, is reported. MRI shows areas of high signal intensity on T2-weighted images in the rhombencephalon and confirmed the clinical diagnosis of a brainstem affection by Listeria monocytogenes. (orig.)

  10. Play the MRI Game

    Science.gov (United States)

    ... Play MRI the Magnetic Miracle Game About the game In the MRI imaging technique, strong magnets and radio waves are used for getting images of inner organs made of soft tissue, compared to X-ray imaging where you get images of hard tissue, ...

  11. Getting an MRI

    Medline Plus

    Full Text Available ... School Butterflies? Read This Chloe & Nurb Meet The Brain (Movie) Quiz: Do You Need a Flu Shot? Got Homework? Here's Help White House Lunch Recipes Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) ...

  12. Getting an MRI

    Medline Plus

    Full Text Available ... Dictionary of Medical Words En Español What Other Kids Are Reading Movie: Digestive System Winter Sports: Sledding, ... a Booger? Getting an MRI (Video) KidsHealth > For Kids > Getting an MRI (Video) Print A A A ...

  13. CT and MRI of the epigastrium - is the MRI competitive?

    International Nuclear Information System (INIS)

    The conclusion drawn in this article is: - CT will continue to rank first as a method for diagnostic evaluation of the entire abdomen. - MRI now offers advantages over CT for diagnostic identification of focal liver lesions, both with regard to detection as such and to a differential diagnosis of liver tumors. - CT continues to be the modality of first choice for diagnostic evaluation of acute pancreatitis. - CT offers advantages for the diagnostic evaluation of the gastrointestinal tract (as e.g. in case of complications in the course of inflammatory intestinal affection). - Interventional measures such as biopsies or abscess drainage will still be best controlled by CT, and MRI is not likely to become a really competitive method for such tasks in the foreseeable future. (orig.)

  14. Lumbosacral epidural lipomatosis: MRI grading

    Energy Technology Data Exchange (ETDEWEB)

    Borre, Daniel G. [Department of MRI, RM-Hastings, Clinica Monte Grande, Monte Grande, Buenos Aires (Argentina); Department of MRI, Oncologic Center of Excellence, Gonnet, Buenos Aires (Argentina); Sociedad Argentina de Radiologia, Arenales 1985 P.B., Ciudad Autonoma de Buenos Aires C1124AAC (Argentina); Borre, Guillermo E. [Department of MRI, RM-Hastings, Clinica Monte Grande, Monte Grande, Buenos Aires (Argentina); Department of MRI, Oncologic Center of Excellence, Gonnet, Buenos Aires (Argentina); Aude, Flavio [Department of MRI, Oncologic Center of Excellence, Gonnet, Buenos Aires (Argentina); Palmieri, Gladys N. [Department of MRI, RM-Hastings, Clinica Monte Grande, Monte Grande, Buenos Aires (Argentina)

    2003-07-01

    Lumbosacral epidural lipomatosis (LEL) is characterized by excessive deposition of epidural fat (EF). The purpose of our retrospective study was to quantify normal and pathologic amounts of EF in order to develop a reproducible MRI grading of LEL. In this study of 2528 patients (1095 men and 1433 women; age range 18-84 years, mean age 47.3 years) we performed a retrospective analysis of MRI exams. We obtained four linear measurements at the axial plane parallel and tangent to the superior end plate of S1 vertebral body: antero-posterior diameter of dural sac (A-Pd DuS), A-Pd of EF, located ventrally and dorsally to the DuS, and A-Pd of the spinal canal (Spi C). We calculated (a) DuS/EF index and (b) EF/Spi C index. We developed the following MRI grading of LEL: normal, grade 0: DuS/EF index {>=}1.5, EF/Spi C index {<=}40%; LEL grade I: DuS/EF index 1.49-1, EF/Spi C index 41-50% (mild EF overgrowth); LEL grade II: DuS/EF index 0.99-0.34, EF/Spi C index 51-74% (moderate EF overgrowth); LEL grade III: DuS/EF index {<=}0.33, EF/Spi C index {>=}75% (severe EF overgrowth). The MRI exams were evaluated independently by three readers. Intra- and interobserver reliabilities were obtained by calculating Kappa statistics. The MRI grading showed the following distribution: grade 0, 2003 patients (79.2%); LEL grade I, 308 patients (12.2%); LEL grade II, 165 patients (6.5%); and LEL grade III, 52 patients (2.1%). The kappa coefficients for intra- and interobserver agreement in a four-grade classification system were substantial to excellent: intraobserver, kappa range 0.79 [95% confidence interval (CI), 0.65-0.93] to 0.82 (95% CI, 0.70-0.95); interobserver, kappa range 0.76 (95% CI, 0.62-0.91) to 0.85 (95% CI, 0.73-0.97). In LEL grade I, there were no symptomatic cases due to fat hypertrophy. LEL grade II was symptomatic in only 24 cases (14.5%). In LEL grade III, all cases were symptomatic. A subgroup of 22 patients (42.3%) showed other substantial spinal pathologies (e

  15. Progression of Emphysema Evaluated by MRI Using Hyperpolarized 3He (HP 3He) Measurements in Patients with Alpha-1-Antitrypsin (A1AT) Deficiency Compared with CT and Lung Function Tests

    Energy Technology Data Exchange (ETDEWEB)

    Stavngaard, T.; Vejby Soegaard, L. (Danish Research Center for Magnetic Resonance, Copenhagen Univ. Hospital Hvidovre, Hvidovre (Denmark)); Batz, M. (Inst. of Physics, Johannes Gutenberg Univ., Mainz (Germany)); Schreiber, L.M. (Dept. of Interventional and Diagnostic Radiology, Johannes Gutenberg Univ. Medical School, Mainz (Germany)); Dirksen, A. (Dept. of Respiratory Medicine, Gentofte Hospital, Univ. of Copenhagen, Copenhagen (Denmark))

    2009-11-15

    Background: The progression of emphysema is traditionally measured by pulmonary function test, with forced expiratory volume in 1 s (FEV1) being the most accepted and used measurement. However, FEV1 is insensitive in detecting mild/slow progression of emphysema because of low reproducibility as compared to yearly decline. Purpose: To investigate the progression of emphysema over a period of 2 years using diffusion-weighted hyperpolarized (HP) 3He magnetic resonance imaging (MRI) in patients with alpha-1-antitrypsin (A1AT) deficiency. Material and Methods: Nine patients with severe A1AT deficiency were studied over a period of 2 years (baseline, year 1, and year 2) with HP 3He MRI using apparent diffusion coefficient (ADC), lung function tests (FEV1 and carbon monoxide lung diffusion capacity [DL,CO]), and computed tomography (CT) using densitometric parameters (15th percentile density [CT-PD15] and relative area of emphysema below -910 HU [CT-RA-910]). Results: Seven patients were scanned three times, one patient two times, and one patient only at baseline. The mean increase in ADC values from first to last HP 3He MR scanning was 3.8% (0.014 cm2/s [SD 0.024 cm2/s]; not significant). The time trends for FEV1, DL,CO, CT-PD15, and CT-RA-910 were all statistically significant. We found a high correlation between ADC and DL,CO (P<0.001). Conclusion: This pilot study indicates the possible use of nonionizing HP 3He MRI for monitoring the progression of emphysema. However, in the future, larger studies are needed to confirm these preliminary results

  16. Progression of Emphysema Evaluated by MRI Using Hyperpolarized 3He (HP 3He Measurements in Patients with Alpha-1-Antitrypsin (A1AT) Deficiency Compared with CT and Lung Function Tests

    International Nuclear Information System (INIS)

    Background: The progression of emphysema is traditionally measured by pulmonary function test, with forced expiratory volume in 1 s (FEV1) being the most accepted and used measurement. However, FEV1 is insensitive in detecting mild/slow progression of emphysema because of low reproducibility as compared to yearly decline. Purpose: To investigate the progression of emphysema over a period of 2 years using diffusion-weighted hyperpolarized (HP) 3He magnetic resonance imaging (MRI) in patients with alpha-1-antitrypsin (A1AT) deficiency. Material and Methods: Nine patients with severe A1AT deficiency were studied over a period of 2 years (baseline, year 1, and year 2) with HP 3He MRI using apparent diffusion coefficient (ADC), lung function tests (FEV1 and carbon monoxide lung diffusion capacity [DL,CO]), and computed tomography (CT) using densitometric parameters (15th percentile density [CT-PD15] and relative area of emphysema below -910 HU [CT-RA-910]). Results: Seven patients were scanned three times, one patient two times, and one patient only at baseline. The mean increase in ADC values from first to last HP 3He MR scanning was 3.8% (0.014 cm2/s [SD 0.024 cm2/s]; not significant). The time trends for FEV1, DL,CO, CT-PD15, and CT-RA-910 were all statistically significant. We found a high correlation between ADC and DL,CO (P3He MRI for monitoring the progression of emphysema. However, in the future, larger studies are needed to confirm these preliminary results

  17. Diffusion MRI and its Role in Neuropsychology.

    Science.gov (United States)

    Mueller, Bryon A; Lim, Kelvin O; Hemmy, Laura; Camchong, Jazmin

    2015-09-01

    Diffusion Magnetic Resonance Imaging (dMRI) is a popular method used by neuroscientists to uncover unique information about the structural connections within the brain. dMRI is a non-invasive imaging methodology in which image contrast is based on the diffusion of water molecules in tissue. While applicable to many tissues in the body, this review focuses exclusively on the use of dMRI to examine white matter in the brain. In this review, we begin with a definition of diffusion and how diffusion is measured with MRI. Next we introduce the diffusion tensor model, the predominant model used in dMRI. We then describe acquisition issues related to acquisition parameters and scanner hardware and software. Sources of artifacts are then discussed, followed by a brief review of analysis approaches. We provide an overview of the limitations of the traditional diffusion tensor model, and highlight several more sophisticated non-tensor models that better describe the complex architecture of the brain's white matter. We then touch on reliability and validity issues of diffusion measurements. Finally, we describe examples of ways in which dMRI has been applied to studies of brain disorders and how identified alterations relate to symptomatology and cognition. PMID:26255305

  18. PET/MRI: A luxury or a necessity?

    Science.gov (United States)

    Carreras-Delgado, J L; Pérez-Dueñas, V; Riola-Parada, C; García-Cañamaque, L

    2016-01-01

    PET/MRI is a new multimodality technique with a promising future in diagnostic imaging. Technical limitations are being overcome. Interference between the two systems (PET and MRI) seems to have been resolved. MRI-based PET attenuation correction can be performed safely. Scan time is acceptable and the study is tolerable, with claustrophobia prevalence similar to that of MRI. Quantification with common parameters, such as Standardized Uptake Value (SUV), shows a fairly good correlation between both systems. However, PET/CT currently provides better results in scan time, scan costs, and patient comfort. Less patient radiation exposure is a big advantage of PET/MRI over PET/CT, which makes it particularly recommended in paediatric and adolescent patients requiring one or more studies. PET/MRI indications are the same as those of PET/CT, given that in cases where MRI is superior to CT, PET/MRI is superior to PET/CT. This superiority is clear in many soft tissue tumours. Moreover, it is common to perform both PET/CT and MRI in neurological diseases, as well as in some tumours, such as breast cancer. A single PET/MRI study replaces both with obvious benefit. MRI also allows other MRI-based PET corrections, such as motion or partial volume effect corrections. The better spatial resolution of MRI allows the transfer of well-defined MRI areas or small volumes of interest to PET image, in order to measure PET biomarkers in these areas. The richness of information of both techniques opens up immense possibilities of synergistic correlation between them. PMID:27349326

  19. MRI of discoid lateral meniscus

    International Nuclear Information System (INIS)

    We retrospectively reviewed the MR examinations of 10 patients (17 knees) with surgically documented discoid lateral meniscus of the knee joint. As MRI of the knee is being used more often, the criteria for diagnosis of this entity with MRI need to be established. We tried to define MRI criteria for the detection of discoid menisci by performing numerical measurements of MR images on a display screen. The transverse diameter of the midbody of a discoid lateral meniscus averaged 21.9 mm (normal control: 8.6 mm), and its proportion to the transverse width of the tibia averaged 29.4% (normal control: 12.0%). The measurable difference in height between the discoid and the medial meniscus was negligible. The number of sagittal sections on which the anterior and posterior horns connected varied from two to five in cases of discoid lateral meniscus, and from zero to two in normal controls. Among these parameters, the transverse diameter and its proportion of the transverse width of the tibia proved to be the most reliable. We concluded that a discoid meniscus is indicated if a transverse diameter of a lateral meniscus exceeds 15 mm (proportion to the tibia: 20%). (author)

  20. Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

    Energy Technology Data Exchange (ETDEWEB)

    Frohwein, Lynn J., E-mail: frohwein@uni-muenster.de; Schäfers, Klaus P. [European Institute for Molecular Imaging, University of Münster, Münster 48149 (Germany); Hoerr, Verena; Faber, Cornelius [Department of Clinical Radiology, University Hospital of Münster, Münster 48149 (Germany)

    2015-07-15

    Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

  1. Correction of MRI-induced geometric distortions in whole-body small animal PET-MRI

    International Nuclear Information System (INIS)

    Purpose: The fusion of positron emission tomography (PET) and magnetic resonance imaging (MRI) data can be a challenging task in whole-body PET-MRI. The quality of the registration between these two modalities in large field-of-views (FOV) is often degraded by geometric distortions of the MRI data. The distortions at the edges of large FOVs mainly originate from MRI gradient nonlinearities. This work describes a method to measure and correct for these kind of geometric distortions in small animal MRI scanners to improve the registration accuracy of PET and MRI data. Methods: The authors have developed a geometric phantom which allows the measurement of geometric distortions in all spatial axes via control points. These control points are detected semiautomatically in both PET and MRI data with a subpixel accuracy. The spatial transformation between PET and MRI data is determined with these control points via 3D thin-plate splines (3D TPS). The transformation derived from the 3D TPS is finally applied to real MRI mouse data, which were acquired with the same scan parameters used in the phantom data acquisitions. Additionally, the influence of the phantom material on the homogeneity of the magnetic field is determined via field mapping. Results: The spatial shift according to the magnetic field homogeneity caused by the phantom material was determined to a mean of 0.1 mm. The results of the correction show that distortion with a maximum error of 4 mm could be reduced to less than 1 mm with the proposed correction method. Furthermore, the control point-based registration of PET and MRI data showed improved congruence after correction. Conclusions: The developed phantom has been shown to have no considerable negative effect on the homogeneity of the magnetic field. The proposed method yields an appropriate correction of the measured MRI distortion and is able to improve the PET and MRI registration. Furthermore, the method is applicable to whole-body small animal

  2. Comparison of HR-MRI, MRA and DSA in measuring intracranial aneurysm%HR-MRI、MRA与DSA在颅内动脉瘤瘤径测量中的对比研究

    Institute of Scientific and Technical Information of China (English)

    王云升; 穆学涛; 牛晓旺; 毛更生; 王宏

    2015-01-01

    AbstractObjective: To investigate the application value of high-resolution magnetic resonance imaging(HR-MRI) in measuring intracranial aneurysm by a comparative analysis with three-dimensional digital subtraction angiography (3D-DSA), three-dimensional time of flight magnetic resonance angiography (3D-TOF MRA). Materials and Methods:A total of 25 patients diagnosed of intracranial aneurysm were enrolled in department of neurosurgery of our hospital from October 2013 to March 2015. Among them, 15 cases were male and 10 female, age 5-60 years old, median age 50.5 years. Firstly all of them underwent conventional MRI sequence to verify the location of intracranial aneurysm, then 3D-TOF MRA sequence was performed, thirdly we performed HR-MRI sequence according to 3D-TOF MRA images (one patient was excluded for poor image quality). And they underwent DSA examination in a week. We measured the maximum width of intracranial aneurysm on the images of 3D-TOF MRA, HR-MRI and 3D-DSA. Statistical analysis was performed using a paired sample Student’st-test for the pairwise comparisons of the differences among HR-MRI, 3D-DSA and 3D-TOF MRA in measuring the maximum width of intracranial aneurysm. We assume the difference is significant statistically whenP0.05).Conclusion:There were differences between HR-MRI and 3D-DSA, HR-MRI and 3D-TOF MRA in measuring the maximum width of intracranial aneurysm, HR-MRI may have higher clinical application value in measuring the actual size of intracranial aneurysm accurately.%目的:研究高分辨率磁共振成像(high-resolution magnetic resonance imaging, HR-MRI)在颅内动脉瘤测量中的应用价值,并与三维数字减影血管造影(three-dimensional DSA,3D-DSA)、三维时间飞跃法磁共振血管成像(three-dimensional time of flight MRA,3D-TOF MRA)作对比。材料与方法选取2013年10月至2015年3月我院神经外科诊断为颅内动脉瘤的患者25例。患者首先行3D-TOF MRA及HR-MRI扫描,并于1

  3. EEG-fMRI: novel methods for gradient artefact correction

    OpenAIRE

    Spencer, G. S.

    2015-01-01

    The general aim of the work detailed in this thesis is to improve the quality of electroencepholography (EEG) recordings acquired simultaneously with functional magnetic resonance imaging (fMRI) data. Simultaneous EEG-fMRI recordings offer significant advantages over the isolated use of each modality for measuring brain function. The high temporal resolution associated with EEG complements the high spatial resolution provided by fMRI. However, combining the two modalities can have signific...

  4. Explaining MRI examinations DVD

    International Nuclear Information System (INIS)

    When conducting MRI examinations, there are various things to be careful of. There is often stress related to the MRI examinations, so in order to perform an examination safely and smoothly, sufficient explanation must be given. An explanation of what to do and what not to do during an examination should be outlined in a brochure given to patients before the examination. There may be many patients who have misgivings about their MRI examinations, so to reduce their anxiousness and deepen their understanding of MRI examinations and to improve the safety and effiency of MRI examinations,; we created a DVD about MRI examinations. We gathered MRI-related safety information and instructions, and assessed the effect that the information might have on patients. We started a workgroup for a project to plan and record a video according to the Storyboard. When editing, we reviewed the length of each segment, the amount of information on screen, and the overall length of the DVD. We discussed the issue within the workgroup and had hospital approval. It was possible for us to complete it without depending on the supplier and the cost was kept to a minimum. Finally, we decided on a viewing location. We asked a hospital volunteers to see a complete DVD and we evaluated their responses by questionnaires. As the result, their understanding and anxieties related to MRI examinations were alleviated, as expected. Their anxiety seemed to be eased. Patients also seemed to have a deeper understanding of MRI examinations having seen an examination being conducted. (author)

  5. MRI in perianal fistulae

    International Nuclear Information System (INIS)

    MRI has become the method of choice for evaluating perianal fistulae due to its ability to display the anatomy of the sphincter muscles orthogonally, with good contrast resolution. In this article we give an outline of the classification of perianal fistulae and present a pictorial assay of sphincter anatomy and the MRI findings in perianal fistulae. This study is based on a retrospective analysis of 43 patients with a clinical diagnosis of perianal fistula. MRI revealed a total of 44 fistulae in 35 patients; eight patients had only perianal sinuses

  6. MRI of brachial plexopathies

    Energy Technology Data Exchange (ETDEWEB)

    Sureka, J. [Department of Radiology, Christian Medical College, Vellore (India)], E-mail: drjyoticmch@rediffmail.com; Cherian, R.A.; Alexander, M.; Thomas, B.P. [Department of Radiology, Christian Medical College, Vellore (India)

    2009-02-15

    Magnetic resonance imaging (MRI) has become the primary imaging technique in the evaluation of brachial plexus pathology, and plays an important role in the identification, localization, and characterization of the cause. Improvements in MRI technique have helped in detecting changes in the signal intensity of nerves, subtle enhancement, and in detecting perineural pathology, thereby refining the differential diagnosis. The present review of the visualization of brachial plexus abnormalities using MRI is based on a review of 26 cases. The causes include trauma and a spectrum of non-traumatic causes, such as acute idiopathic/viral plexitis, metastases, immune-mediated plexitis, and mass lesions compressing the brachial plexus.

  7. Good practices in EEG-MRI: The utility of retrospective synchronization and PCA for the removal of MRI gradient artefacts

    OpenAIRE

    Mandelkow, H; Brandeis, D; Boesiger, P

    2010-01-01

    The electroencephalogram (EEG) recorded during magnetic resonance imaging (MRI) inside the scanner is obstructed by the MRI gradient artefact (MGA) originating from the electromagnetic interference of the MRI with the sensitive measurement of electrical scalp potentials. Post-processing algorithms based on average artefact subtraction (AAS) have proven to be efficient in removing the MGA. However, the residual MGA after AAS still limits the quality and usable bandwidth of the EEG data despite...

  8. 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 ...

  9. Brain MRI in Parkinson's disease

    NARCIS (Netherlands)

    Meijer, F.J.A.; Goraj, B.M.

    2014-01-01

    In this review article, conventional brain MRI and advanced MRI techniques in Parkinson`s disease (PD) are discussed, with emphasis on clinical relevance. Conventional brain MRI sequences generally demonstrate limited abnormalities specific for PD and in clinical practice brain MRI is mainly used to

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

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

  11. Measurement of the AT and the CCD angle of macerated cadaver femora: a comparative study between CT and MRI measurements; Die Bestimmung des AT- und CCD-Winkels am mazerierten Leichenfemur - Eine Vergleichsstudie zwischen CT- und MRT-Messung und Direktmessung am Praeparat

    Energy Technology Data Exchange (ETDEWEB)

    Nuss, V.; Herber, S.; Kreitner, K.-F.; Thelen, M. [Universitaetsklinik Mainz (Germany). Klinik und Poliklinik fuer Radiologie; Kuellmer, K. [Universitaetsklinik Mainz (Germany). Klinik fuer Orthopaedie

    2003-10-01

    Purpose: To compare measurements of the real AT (femoral antetorsion) and CCD (caput-scollum-diaphysis) angle by computed tomography (CT) and magnetic resonance imaging (MRI) of hip specimen using direct measurements as reference standard, and to show that measurements by MRI can replace CT measurements and ma help avoiding X-ray exposition. Materials and methods: CT and MRI measurements were obtained on 25 in water-arrested macerated human femora. Postprocessing was done by 4 independent readers on a workstation using a dedicated 3D-software. Direct measurements of the real AT and the CCD angle were used as reference standard. The analysis included Student's test for paired values, interobserver variability using intra-class correlation coefficients (ICC), maximum and middle divergence of the angles, and Bland-Altman plots. Results: For determining AT and the CCD angle with CT and MRI, good correlation was found between the 4 readers and with measurements using the reference standard. ICCs were 0.97 and 0.90 for measuring AT and CCD angle with CT, and 0.95 and 0.71 for measurements with MRI, respectively. Mean divergence between CT measurements and those of the reference standard was 0.8 for AT and 0.7 for the CDD-angle. Mean divergence between MRI measurements and those of the reference standard was 0.3 for AT and -0.4 for the CCD-angle. Mean divergences between CT and MRI measurements of AT and CCD-angle were 0.5 . Neither systematic errors nor dependences on the qualitative size of the reference data were evident in the divergences of measurements. (orig.) [German] Ziel: Messung des reellen Femurantetorsions (AT)- und Caput-Collum-Diaphysenwinkels (CCD-Winkels) im computer (CT)- und magnetresonanz (MR)-tomographischen Bild sowie Direktmessungen am Praeparat im Vergleich. Es soll gezeigt werden, dass die mit einer Strahlenexposition verbundene computertomographische durch die roentgenstrahlenfreie MR-tomographische Messung ersetzt werden kann. Material und

  12. Advanced flow MRI: emerging techniques and applications.

    Science.gov (United States)

    Markl, M; Schnell, S; Wu, C; Bollache, E; Jarvis, K; Barker, A J; Robinson, J D; Rigsby, C K

    2016-08-01

    Magnetic resonance imaging (MRI) techniques provide non-invasive and non-ionising methods for the highly accurate anatomical depiction of the heart and vessels throughout the cardiac cycle. In addition, the intrinsic sensitivity of MRI to motion offers the unique ability to acquire spatially registered blood flow simultaneously with the morphological data, within a single measurement. In clinical routine, flow MRI is typically accomplished using methods that resolve two spatial dimensions in individual planes and encode the time-resolved velocity in one principal direction, typically oriented perpendicular to the two-dimensional (2D) section. This review describes recently developed advanced MRI flow techniques, which allow for more comprehensive evaluation of blood flow characteristics, such as real-time flow imaging, 2D multiple-venc phase contrast MRI, four-dimensional (4D) flow MRI, quantification of complex haemodynamic properties, and highly accelerated flow imaging. Emerging techniques and novel applications are explored. In addition, applications of these new techniques for the improved evaluation of cardiovascular (aorta, pulmonary arteries, congenital heart disease, atrial fibrillation, coronary arteries) as well as cerebrovascular disease (intra-cranial arteries and veins) are presented. PMID:26944696

  13. MRI of the Chest

    Science.gov (United States)

    ... MRI scanners are air-conditioned and well-lit. Music may be played through the headphones to help ... in diagnosing a broad range of conditions, including cancer, heart and vascular disease, heart valve abnormalities, bone ...

  14. MRI of the shoulder

    International Nuclear Information System (INIS)

    Magnetic resonance imaging has become available at a time in which shoulder pathology is more frequently seen. It is a noninvasive procedure that does not use ionizing radiation. It provides detailed visualization of soft-tissue structures that is not possible with other imaging modalities. Though not as widely available as conventional radiographs or computed tomography scanning, the number of MRI units worldwide is increasing steadily. The main features of the present book are as follows: The physical basis of Magnetic Resonance Imaging (MRI), normal shoulder anatomy and MRI, diagnosis of shoulder disorders, MRI of patients with shoulder pain or instability, case studies as well as treatment of shoulder disorders. (orig./MG) With 145 figs

  15. Combined PET/MRI

    DEFF Research Database (Denmark)

    Bailey, D. L.; Pichler, B. J.; Gückel, B.;

    2015-01-01

    This paper summarises key themes and discussions from the 4th international workshop dedicated to the advancement of the technical, scientific and clinical applications of combined positron emission tomography (PET)/magnetic resonance imaging (MRI) systems that was held in Tübingen, Germany, from...... February 23 to 27, 2015. Specifically, we summarise the three days of invited presentations from active researchers in this and associated fields augmented by round table discussions and dialogue boards with specific topics. These include the use of PET/MRI in cardiovascular disease, paediatrics, oncology......, neurology and multi-parametric imaging, the latter of which was suggested as a key promoting factor for the wider adoption of integrated PET/MRI. Discussions throughout the workshop and a poll taken on the final day demonstrated that attendees felt more strongly that PET/MRI has further advanced in both...

  16. MRI of myelitis

    OpenAIRE

    Hodel, J.; Outteryck, O; Jissendi, P; Zins, M.; Leclerc, X; Pruvo, J P

    2012-01-01

    The diagnosis of myelitis relies on MRI. The purpose of this review is to describe the imaging findings in patients with myelitis through clinical cases. MR findings in Multiple Sclerosis, Neuromyelitis Optica and others Transverse Myelitis are highlighted.

  17. MRI of intracranial calcifications

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jin Wha; Chang, Kee Hyun; Park, Jung Mi; Han, Moon Hee; Han, Man Chung; Kim, Chu Wan [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1988-12-15

    Recently computed tomography(CT) has been rapidly replaced by magnetic resonance imaging (MRI) in diagnosis of majority of intracranial diseases. But MRI still has some limitation, one of which is its inferiority in detecting calcification. MRI of intracranial calcification has been known to be variable in signal intensity. We retrospectively analyzed the MRI of 26 patients with intracranial calcified lesions in order to evaluate the MR intensity of calcification and to assess the capability of MRI in detecting calcification in various intracranial lesions. All the MRI were obtained using routine T1-and T2-weighted spin eco pulse sequences on 2.0T superconducting system. The 26 patients consisted of 13 brain tumors (4 oligodendrogliomas, 2 craniopharyngiomas, 2 astrocytomas, 1 gem cell tumor, 1 medulloblastoma, 1 ependympma, and pathologically unconfirmed 2 cases), 11 infectious diseases (1 paragonimiasis, 1 sparganosis, 2 cysticercosis, 3 tuberculosis, and 4 unknown cases), and 2 undetermined pathologies. Eighty-two percent (9/11) of infections disease, and 50% (1/2) of undetermined group showed signal diminution or signal void on both T1-and T2-weighted image (T1W1, T2W1). Twenty-four percent (3/13) of brain tumors showed signal diminution on both T1W1 and T2W1. In 46% (6/13) and 61% (8/13) of brain tumors the signal intensities were isointense on T1W1 and T1W1, respectively. Unexpectedly, 3 oligodendrogliomas showed high signal intensity on T1W1, two of which showed com plexed signal intensity mixed with high, iso, and low signal intensities on T2W1. In remained cases (18% (2/11) of infectious diseases and 50% (1/2) of undetermined group) the signal intensities were mixed. With simultaneous review of CT and MRI in each case, the calcification (at least one in cases showing multiple ones) was identifiable on MRI in 62% (8/13) of rumors, 82% (9/11) of infectious diseases, and 100% (2/2) in undetermined group. In 36% (4/11) of infectious diseases, fewer number of

  18. MRI of the penis

    OpenAIRE

    Kirkham, A

    2012-01-01

    MRI of the penis is an expensive test that is not always superior to clinical examination or ultrasound. However, it shows many of the important structures, and in particular the combination of tumescence from intracavernosal alprostadil, and high-resolution T2 sequences show the glans, corpora and the tunica albuginea well. In this paper we summarise the radiological anatomy and discuss the indications for MRI. For penile cancer, it may be useful in cases where the local stage is not apparen...

  19. MRI assessment program

    International Nuclear Information System (INIS)

    The MRI Assessment Program involves installation and operation of five MRI units in Australian public hospitals and the evaluation at each unit of the cost and efficacy of the technology over a period of two years. This first report in a series presents preliminary usage and cost data for the year to 30 June 1987 as well as describing the background and the data set. 6 figs., tabs

  20. MRI in osteochondrosis dissecans

    International Nuclear Information System (INIS)

    The osseous manifestations of osteochondrosis dissecans are well demonstrated by conventional and computerised tomography. Beyond that, magnetic resonance imaging (MRI) is effective in evaluating the vitality and loosening of an osseous dissecate. Subchondral cavities and cartilaginous defects are detected with high acccuracy. Further, MRI seems to be a useful method in childhood to differentiate a variant irregularity of the osseous articular surface from definite osteochondrosis dissecans. (orig.)

  1. MRI of plantar fasciitis

    Energy Technology Data Exchange (ETDEWEB)

    Roger, B.; Grenier, P. [Service de Radiologie Polyvalente Diagnostique et Interventionelle, Hopital de la Pitie, 83, boulevard de l`Hopital, F-75651 Paris Cedex 13 (France)

    1997-12-01

    At present, MRI is the only imaging method that can precisely visualize lesions of the superficial plantar aponeurosis, whether they be musculoaponeurositides, enthesopathies or tears, and whether they be acute or chronic, with or without complications. By its direct visualization of the lesion, MRI enables an accurate assessment of the injury to be made and thereby better orients the therapeutic strategy. (orig.) With 11 figs., 15 refs.

  2. MRI of coronary artery atherosclerosis in rabbits: Histopathology-MRI correlation and atheroma characterization

    Directory of Open Access Journals (Sweden)

    Singh Ram B

    2004-05-01

    Full Text Available Abstract Background and objectives We report in vivo magnetic resonance imaging (MRI characteristics and histopathology correlation of the thrombus formation in atherosclerosis the rabbit animal model. Design and methods Atherosclerosis was induced in white male rabbits with vegetable ghee followed oxidized diet. Baseline MRI of atherosclerosis-recruited rabbits was done and later animals were used for atheroma histopathology characterization. Contiguous cross-sectional T2-weighted fast spin echo MRI images were compared by coronary histopathology. In all animals, coronary aortic wall thickening and atheroma size was measured using MRI. Results MRI images and digitized histological sections confirmed intraluminal thrombus in 6 (67% of the 9 animals. MRI data showed correlation with the histopathology for aortic wall thickness (R2 = 0.82, P 2 = 0.88, P 2 = 0.77, P Conclusion The combination of in vivo MRI and comparison with histopathology images of rabbit coronary thrombus may be a research tool for understanding of the pathogenesis of acute coronary plaques.

  3. Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

    Energy Technology Data Exchange (ETDEWEB)

    Muhle, C. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Brossmann, J. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Melchert, U.H. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Schroeder, C. [Radiologische Abt., Universitaets-Kinderklinik, Christian-Albrechts-Universitaet, Kiel (Germany); Boer, R. de [Philips Medical Systems, Best (Netherlands); Spielmann, R.P. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany); Heller, M. [Klinik fuer Radiologische Diagnostik, Univ. Kiel (Germany)

    1995-12-31

    To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

  4. Functional MRI of the patellofemoral joint: comparison of ultrafast MRI, motion-triggered cine MRI and static MRI

    International Nuclear Information System (INIS)

    To evaluate the feasibility and usefulness of ultrafast MRI (u), patellar tracking from 30 of flexion to knee extension (0 ) was analysed and compared with motion-triggered cine MRI (m) and a static MRI technique (s). The different imaging methods were compared in respect of the patellofemoral relationship, the examination time and image quality. Eight healthy subjects and four patients (in total 18 joints) with patellar subluxation or luxation were examined. Significant differences between the static MRI series without quadriceps contraction and the functional MRI studies (motion-triggered cine MRI and ultrafast MRI) were found for the patellar tilt angle. In the dynamic joint studies there was no statistical difference of the regression coefficients between the motion-triggered cine MRI studies and the ultrafast MRI studies. The findings of the functional MRI studies compared with the static MRI images were significantly different for the lateralisation of the patella, expressed by the lateral patellar displacement and bisect offset. No significant differences in patellar lateralisation were found between motion-triggered cine MRI and ultrafast MRI. Ultrafast MRI was superior to motion-triggered cine MRI in terms of the reduction in imaging time and improvement of the image quality. (orig.)

  5. Posttraumatic pseudolipoma: MRI appearances

    International Nuclear Information System (INIS)

    The goal of this study was to describe the MRI characteristics of posttraumatic pseudolipomas. Ten patients with previous history of blunt trauma or local surgery were investigated with MRI at the level of their deformity. The etiology was blunt trauma in eight patients and postoperative trauma in two. For all patients medical documentation, in the form of clinical history and physical examination, confirmed that a visible hematoma was present acutely at the same location following the injury and that the contour deformity subsequently appeared. All patients underwent liposuction. Preoperative bilateral MRI examinations were performed on all patients. The mean clinical follow-up was 17.8 months. MRI examinations were interpreted in consensus by two experienced musculoskeletal radiologists with attention to fatty extension (subcutaneous fatty thickness and anatomical extension), asymmetry compared with the asymptomatic side, the presence or absence of fibrous septae or nonfatty components, and patterns of contrast enhancement. Ten posttraumatic pseudolipomas were identified. Clinically, they showed as subcutaneous masses with the consistency of normal adipose tissue. Their locations were the abdomen (n=1), hip (n=1), the upper thigh (n=6), the knee (n=1), and the ankle (n=1). On MRI examinations, using the contralateral side as a control, pseudolipomas appeared as focal fatty masses without a capsule or contrast enhancement. Posttraumatic pseudolipomas may develop at a site of blunt trauma or surgical procedures often antedated by a soft tissue hematoma. Characteristic MRI findings are unencapsulated subcutaneous fatty masses without contrast enhancement. (orig.)

  6. MRI of fish

    International Nuclear Information System (INIS)

    Recently, rats and mice are popular and useful as an experimental model for MRI. However, MRI for fishes has been unknown. This study aimed to investigate the usefulness of living fishes as a new experimental model for MRI. MR images were collected with a spin-echo pulse sequence (SE) or echo-planar imaging pulse sequence (EPI) using 2T MR imaging system for animal. Carp, which was able to be alive for a long time in the air, was examined. Enhancement study was examined by use of Gd-DOTMA (gadolinium hydrogen alpha, alpha', alpha'', alpha'''-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). On both SE and EPI images, the internal components of the head and chest in carp were clearly recognized. On the T1-weighted image acquisition time of MRI with sufficient resolution was short (in about one minute) in comparison with that of rat. The head in carp was well enhanced by administration of Gd-DOTMA on the T1-weighted image. In addition, the time course of contrast enhancement effect of images was observed after administration of Gd-DOTMA. The authors concluded that fishes, such as a carp, can be readily imaged on MRI, and could be potential in the future investigation of contrast enhancement effect and relaxation effect as a living body phantom for MRI. (author)

  7. Posttraumatic pseudolipoma: MRI appearances

    Energy Technology Data Exchange (ETDEWEB)

    Theumann, N.; Abdelmoumene, A.; Wintermark, M.; Schnyder, P.; Gailloud, M.C.; Resnick, D. [CHUV, Department of Diagnostic and Interventional Radiology, Lausanne (Switzerland)

    2005-09-01

    The goal of this study was to describe the MRI characteristics of posttraumatic pseudolipomas. Ten patients with previous history of blunt trauma or local surgery were investigated with MRI at the level of their deformity. The etiology was blunt trauma in eight patients and postoperative trauma in two. For all patients medical documentation, in the form of clinical history and physical examination, confirmed that a visible hematoma was present acutely at the same location following the injury and that the contour deformity subsequently appeared. All patients underwent liposuction. Preoperative bilateral MRI examinations were performed on all patients. The mean clinical follow-up was 17.8 months. MRI examinations were interpreted in consensus by two experienced musculoskeletal radiologists with attention to fatty extension (subcutaneous fatty thickness and anatomical extension), asymmetry compared with the asymptomatic side, the presence or absence of fibrous septae or nonfatty components, and patterns of contrast enhancement. Ten posttraumatic pseudolipomas were identified. Clinically, they showed as subcutaneous masses with the consistency of normal adipose tissue. Their locations were the abdomen (n=1), hip (n=1), the upper thigh (n=6), the knee (n=1), and the ankle (n=1). On MRI examinations, using the contralateral side as a control, pseudolipomas appeared as focal fatty masses without a capsule or contrast enhancement. Posttraumatic pseudolipomas may develop at a site of blunt trauma or surgical procedures often antedated by a soft tissue hematoma. Characteristic MRI findings are unencapsulated subcutaneous fatty masses without contrast enhancement. (orig.)

  8. Mapping Human Brain Function with MRI at 7 Tesla

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ In the past decade, the most significant development in MRI is the introduction of fMRI, which permits the mapping of human brain function with exquisite details noninvasively. Functional mapping can be achieved by measuring changes in the blood oxygenation level (I.e. The BOLD contrast) or cerebral blood flow.

  9. Lying about Facial Recognition: An fMRI Study

    Science.gov (United States)

    Bhatt, S.; Mbwana, J.; Adeyemo, A.; Sawyer, A.; Hailu, A.; VanMeter, J.

    2009-01-01

    Novel deception detection techniques have been in creation for centuries. Functional magnetic resonance imaging (fMRI) is a neuroscience technology that non-invasively measures brain activity associated with behavior and cognition. A number of investigators have explored the utilization and efficiency of fMRI in deception detection. In this study,…

  10. Future perspectives for intraoperative MRI.

    Science.gov (United States)

    Jolesz, Ferenc A

    2005-01-01

    MRI-guided neurosurgery not only represents a technical challenge but a transformation from conventional hand-eye coordination to interactive navigational operations. In the future, multimodality-based images will be merged into a single model, in which anatomy and pathologic changes are at once distinguished and integrated into the same intuitive framework. The long-term goals of improving surgical procedures and attendant outcomes, reducing costs, and achieving broad use can be achieved with a three-pronged approach: 1. Improving the presentation of preoperative and real-time intraoperative image information 2. Integrating imaging and treatment-related technology into therapy delivery systems 3. Testing the clinical utility of image guidance in surgery The recent focus in technology development is on improving our ability to understand and apply medical images and imaging systems. Areas of active research include image processing, model-based image analysis, model deformation, real-time registration, real-time 3D (so-called "four-dimensional") imaging, and the integration and presentation of image and sensing information in the operating room. Key elements of the technical matrix also include visualization and display platforms and related software for information and display, model-based image understanding, the use of computing clusters to speed computation (ie, algorithms with partitioned computation to optimize performance), and advanced devices and systems for 3D device tracking (navigation). Current clinical applications are successfully incorporating real-time and/or continuously up-dated image-based information for direct intra-operative visualization. In addition to using traditional imaging systems during surgery, we foresee optimized use of molecular marker technology, direct measures of tissue characterization (ie, optical measurements and/or imaging), and integration of the next generation of surgical and therapy devices (including image

  11. Hepatocellular MR contrast agents: Enhancement characteristics of liver parenchyma and portal vein after administration of gadoxetic acid in comparison to gadobenate dimeglumine

    International Nuclear Information System (INIS)

    Purpose: To investigate the enhancement characteristics of liver parenchyma and portal vein as well as the portal vein-to liver contrast in Gd-EOB-DTPA- and Gd-BOPTA-enhanced abdominal MRI. Materials and methods: The local institutional review board approved this retrospective study. A total of 70 patients (30 female, 40 male) without relevant liver disease underwent either Gd-EOB-DTPA-enhanced (35 patients, dose 0.025 mmol/kg) or Gd-BOPTA-enhanced (35 patients, dose 0.1 mmol/kg) abdominal MRI. Signal-to-noise ratios (SNR) for the portal vein and the liver as well as portal vein-to-liver contrast-to-noise ratios (CNR) were calculated for three consecutive arterial phases, one portal venous phase and one delayed imaging phase. Results: The liver SNR showed higher values for the Gd-BOPTA group in the arterial and portal venous phases (statistically significant for the second and third arterial phase), while the liver SNR in the delayed phase was higher for the Gd-EOB-DTPA group. The portal venous SNR as well as the portal vein-to-liver CNR was higher in the Gd-BOPTA group in all imaging phases (statistically significant in all phases except for the first arterial phase). Conclusion: The enhancement of liver parenchyma and portal vein as well as the portal vein-to-liver contrast in the arterial and portal venous imaging phases were higher for patients receiving Gd-BOPTA compared with Gd-EOB-DTPA at the respective recommended doses. Gd-BOPTA might therefore enable better evaluation of the portal vein

  12. MRI-based flow measurements in the main pulmonary artery to detect pulmonary arterial hypertension in patients with cystic fibrosis; MRT-basierte Flussmessungen im Truncus pulmonalis zur Detektion einer pulmonal-arteriellen Hypertonie in Patienten mit zystischer Fibrose

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, T.; Anjorin, A.; Abolmaali, N. [TU Dresden (Germany). OncoRay, Biologisches und Molekulares Imaging; Posselt, H. [Frankfurt Univ. (Germany). Klinik fuer Paediatrie I, Muskoviszidoseambulanz; Smaczny, C. [Frankfurt Univ. (Germany). Medizinische Klinik I, Pneumologie und Allergologie; Vogl, T.J. [Frankfurt Univ. (Germany). Inst. fuer Diagnostische und Interventionelle Radiologie

    2009-02-15

    Development of pulmonary arterial hypertension (PH) is a common problem in the course of patients suffering from cystic fibrosis (CF). This study was performed to evaluate MRI based flow measurements (MR{sub venc}; Velocity ENCoding) to detect signs of an evolving PH in patients suffering from CF. 48 patients (median age: 16 years, range: 10 - 40 years, 25 female) suffering from CF of different severity (mean FEV1: 74 % {+-} 23, mean Shwachman-score: 63 {+-} 10) were examined using MRI based flow measurements of the main pulmonary artery (MPA). Phase-contrast flash sequences (TR: 9.6 ms, TE: 2.5 ms, bandwidth: 1395 Hertz/Pixel) were utilized. Results were compared to an age- and sex-matched group of 48 healthy subjects. Analyzed flow data where: heart frequency (HF), cardiac output (HZV), acceleration time (AT), proportional acceleration time related to heart rate (ATr), mean systolic blood velocity (MFG), peak velocity (Peak), maximum flow (Fluss{sub max}), mean flow (Fluss{sub mitt}) and distensibility (Dist). The comparison of means revealed significant differences only for MFG, Fluss{sub max} and Dist, but overlap was marked. However, using a scatter-plot of AT versus MFG, it was possible to identify five CF-patients demonstrating definite signs of PH: AT = 81 ms {+-} 14, MFG = 46 {+-} 11 cm/s, Dist = 41 % {+-} 7. These CF-patients where the most severely affected in the investigated group, two of them were listed for complete heart and lung transplantation. The comparison of this subgroup and the remaining CF-patients revealed a highly significant difference for the AT (p = 0.000001) without overlap. Screening of CF-patients for the development of PH using MR{sub venc} of the MPA is not possible. In later stages of disease, the quantification of AT, MFG and Dist in the MPA may be useful for the detection, follow-up and control of therapy of PH. MR{sub venc} of the MPA completes the MRI-based follow-up of lung parenchyma damage in patients suffering from CF

  13. Altered Dynamics of the fMRI Response to Faces in Individuals with Autism

    Science.gov (United States)

    Kleinhans, Natalia M.; Richards, Todd; Greenson, Jessica; Dawson, Geraldine; Aylward, Elizabeth

    2016-01-01

    Abnormal fMRI habituation in autism spectrum disorders (ASDs) has been proposed as a critical component in social impairment. This study investigated habituation to fearful faces and houses in ASD and whether fMRI measures of brain activity discriminate between ASD and typically developing (TD) controls. Two identical fMRI runs presenting masked…

  14. MRI of the lung

    Energy Technology Data Exchange (ETDEWEB)

    Kauczor, Hans-Ulrich (ed.) [University Clinic Heidelberg (Germany). Diagnostic and Interventional Radiology

    2009-07-01

    For a long time, only chest X-ray and CT were used to image lung structure, while nuclear medicine was employed to assess lung function. During the past decade significant developments have been achieved in the field of magnetic resonance imaging (MRI), enabling MRI to enter the clinical arena of chest imaging. Standard protocols can now be implemented on up-to-date scanners, allowing MRI to be used as a first-line imaging modality for various lung diseases, including cystic fibrosis, pulmonary hypertension and even lung cancer. The diagnostic benefits stem from the ability of MRI to visualize changes in lung structure while simultaneously imaging different aspects of lung function, such as perfusion, respiratory motion, ventilation and gas exchange. On this basis, novel quantitative surrogates for lung function can be obtained. This book provides a comprehensive overview of how to use MRI for imaging of lung disease. Special emphasis is placed on benign diseases requiring regular monitoring, given that it is patients with these diseases who derive the greatest benefit from the avoidance of ionizing radiation. (orig.)

  15. MRI in Japanese encephalitis

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S. [Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India). Dept. of Radiology; Misra, U.K. [Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India). Dept. of Neurology; Kalita, J. [Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India). Dept. of Neurology; Salwani, V. [Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India). Dept. of Radiology; Gupta, R.K. [Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India). Dept. of Radiology; Gujral, R. [Sanjay Gandhi Post Graduate Inst. of Medical Sciences, Lucknow (India). Dept. of Radiology

    1997-03-01

    We document the MRI features in seven patients with Japanese encephalitis. MRI was carried out on a 1.5 T system within 10-60 days of onset. In all the patients MRI revealed bilateral thalamic lesions, haemorrhagic in five. Signal changes were present in the cerebrum in four patients, the midbrain and cerebellum in three each, the pons in two and the basal ganglia in one. The lesions were haemorrhagic in three of the four patients with lesions in the cortex, two of the three with lesions in the midbrain and cerebellum, but the pontine lesions were haemorrhagic in both patients. Spinal cord involvement was seen in one of the three patients who underwent MRI. In two patients MRI was repeated 3 years after the onset, showing marked reduction in abnormal signal; and all the lesions gave low signal on both T1- and T2-weighted images. Bilateral thalamic involvement, especially haemorrhagic, may be considered characteristic of Japanese encephalitis, especially in endemic areas. (orig.)

  16. MRI of the lung

    International Nuclear Information System (INIS)

    For a long time, only chest X-ray and CT were used to image lung structure, while nuclear medicine was employed to assess lung function. During the past decade significant developments have been achieved in the field of magnetic resonance imaging (MRI), enabling MRI to enter the clinical arena of chest imaging. Standard protocols can now be implemented on up-to-date scanners, allowing MRI to be used as a first-line imaging modality for various lung diseases, including cystic fibrosis, pulmonary hypertension and even lung cancer. The diagnostic benefits stem from the ability of MRI to visualize changes in lung structure while simultaneously imaging different aspects of lung function, such as perfusion, respiratory motion, ventilation and gas exchange. On this basis, novel quantitative surrogates for lung function can be obtained. This book provides a comprehensive overview of how to use MRI for imaging of lung disease. Special emphasis is placed on benign diseases requiring regular monitoring, given that it is patients with these diseases who derive the greatest benefit from the avoidance of ionizing radiation. (orig.)

  17. Contrast agents for MRI

    International Nuclear Information System (INIS)

    Contrast agents are divided into two categories. The first one is paramagnetic compounds, including lanthanides like gadolinium, which mainly reduce the longitudinal (T1) relaxation property and result in a brighter signal. The second class consists of super-paramagnetic magnetic nanoparticles (SPMNPs) such as iron oxides, which have a strong effect on the transversal (T2) relaxation properties. SPMNPs have the potential to be utilized as excellent probes for magnetic resonance imaging (MRI). For instance, clinically benign iron oxide and engineered ferrite nanoparticles provide a good MRI probing capability for clinical applications. Furthermore, the limited magnetic property and inability to escape from the reticuloendothelial system (RES) of the used nanoparticles impede their further advancement. Therefore, it is necessary to develop the engineered magnetic nanoparticle probes for the next-generation molecular MRI. Considering the importance of MRI in diagnosing diseases, this paper presents an overview of recent scientific achievements in the development of new synthetic SPMNP probes whereby the sensitive and target-specific observation of biological events at the molecular and cellular levels is feasible. - Highlights: • This paper studies the contrast agents for MRI. • Fe―Co alloys and Mn-ferrites exhibit suitable contrast enhancement. • Nonhydrolytic thermal-decomposition synthetic method is suitable to produce MNPs. • This method allows controlling the size, magnetic dopants, magneto-crystalline anisotropy. • The increase in the superparamagnetic size leads to the contrast-enhancement

  18. An fMRI Study Dissociating Distance Measures Computed by Broca’s Area in Movement Processing: Clause boundary vs Identity

    Directory of Open Access Journals (Sweden)

    Andrea eSanti

    2015-05-01

    Full Text Available Behavioral studies of sentence comprehension suggest that processing long-distance dependencies is subject to interference effects when Noun Phrases (NP similar to the dependency head intervene the dependency. Neuroimaging studies converge in localizing such effects to Broca’s area, showing that activity in Broca’s area increases with the number of NP interveners crossed by a moved NP of the same type. To test if NP interference effects are modulated by adding an intervening clause boundary, which should by hypothesis increase the number of successive-cyclic movements, we conducted an fMRI study contrasting NP interveners with clausal (CP interveners. Our design thus had two components: (I the number of NP interveners crossed by movement was parametrically modulated; (II CP-intervention was contrasted with NP-intervention. The number of NP interveners parametrically modulated a cluster straddling left BA44/45 of Broca’s area, replicating earlier studies. Adding an intervening clause boundary did not significantly modulate the size of the NP interference effect in Broca’s area. Yet, such an interaction effect was observed in the Superior Frontal Gyrus (SFG. Therefore, the involvement of Broca’s area in processing syntactic movement is best captured by memory mechanisms affected by a grammatically instantiated type-identity (ie, NP intervention.

  19. Sodium MRI in human heart: a review.

    Science.gov (United States)

    Bottomley, Paul A

    2016-02-01

    This paper offers a critical review of the properties, methods and potential clinical application of sodium ((23)Na) MRI in human heart. Because the tissue sodium concentration (TSC) in heart is about ~40 µmol/g wet weight, and the (23)Na gyromagnetic ratio and sensitivity are respectively about one-quarter and one-11th of that of hydrogen ((1)H), the signal-to-noise ratio of (23)Na MRI in the heart is about one-6000th of that of conventional cardiac (1)H MRI. In addition, as a quadrupolar nucleus, (23)Na exhibits ultra-short and multi-component relaxation behavior (T1 ~ 30 ms; T2 ~ 0.5-4 ms and 12-20 ms), which requires fast, specialized, ultra-short echo-time MRI sequences, especially for quantifying TSC. Cardiac (23)Na MRI studies from 1.5 to 7 T measure a volume-weighted sum of intra- and extra-cellular components present at cytosolic concentrations of 10-15 mM and 135-150 mM in healthy tissue, respectively, at a spatial resolution of about 0.1-1 ml in 10 min or so. Currently, intra- and extra-cellular sodium cannot be unambiguously resolved without the use of potentially toxic shift reagents. Nevertheless, increases in TSC attributable to an influx of intra-cellular sodium and/or increased extra-cellular volume have been demonstrated in human myocardial infarction consistent with prior animal studies, and arguably might also be seen in future studies of ischemia and cardiomyopathies--especially those involving defects in sodium transport. While technical implementation remains a hurdle, a central question for clinical use is whether cardiac (23)Na MRI can deliver useful information unobtainable by other more convenient methods, including (1)H MRI. PMID:25683054

  20. Characterization of the collagen component of cartilage repair tissue of the talus with quantitative MRI: comparison of T2 relaxation time measurements with a diffusion-weighted double-echo steady-state sequence (dwDESS)

    Energy Technology Data Exchange (ETDEWEB)

    Kretzschmar, M.; Hainc, N.; Studler, U. [University Hospital Basel, Department of Radiology, Basel (Switzerland); Bieri, O. [University Hospital Basel, Division of Radiological Physics, Basel (Switzerland); Miska, M. [University Hospital, Department of Orthopedics, Heidelberg (Germany); Wiewiorski, M.; Valderrabano, V. [University Hospital Basel, Department of Orthopedic Surgery, Basel (Switzerland)

    2015-04-01

    The purpose of this study was to characterize the collagen component of repair tissue (RT) of the talus after autologous matrix-induced chondrogenesis (AMIC) using quantitative T2 and diffusion-weighted imaging. Mean T2 values and diffusion coefficients of AMIC-RT and normal cartilage of the talus of 25 patients with posttraumatic osteochondral lesions and AMIC repair were compared in a cross-sectional design using partially spoiled steady-state free precession (pSSFP) for T2 quantification, and diffusion-weighted double-echo steady-state (dwDESS) for diffusion measurement. RT and cartilage were graded with modified Noyes and MOCART scores on morphological sequences. An association between follow-up interval and quantitative MRI measures was assessed using multivariate regression, after stratifying the cohort according to time interval between surgery and MRI. Mean T2 of the AMIC-RT and cartilage were 43.1 ms and 39.1 ms, respectively (p = 0.26). Mean diffusivity of the RT (1.76 μm{sup 2}/ms) was significantly higher compared to normal cartilage (1.46 μm{sup 2}/ms) (p = 0.0092). No correlation was found between morphological and quantitative parameters. RT diffusivity was lowest in the subgroup with follow-up >28 months (p = 0.027). Compared to T2-mapping, dwDESS demonstrated greater sensitivity in detecting differences in the collagen matrix between AMIC-RT and cartilage. Decreased diffusivity in patients with longer follow-up times may indicate an increased matrix organization of RT. (orig.)

  1. Volume measurement of brain using 3.0T MRI in 140 normal Chinese and data analysis%采用3.0T MRI 对正常人脑体积定量测量研究(附140例分析)

    Institute of Scientific and Technical Information of China (English)

    崔彩霞; 周存河; 崔慧先; 刘怀军; 周立霞; 黄渤源; 贺丹

    2014-01-01

    目的:采用3.0T MRI 对正常志愿者脑体积进行定量测量,确定正常值参考范围,并探讨其与年龄和性别的相关性。方法采用CE Signa EXCITE 3.0T高分辨MRI对140例健康志愿者(男性73例,女性67例,年龄10~84岁,平均45.8±18.3)进行头颅MRI 3DT1成像,在AW4.2工作站上采用半自动方法计算脑体积。并对不同性别、年龄进行统计分析。结果脑体积95%可信区间:男性为1480.15±141.04cm 3,女性为1322.91±110.11cm 3。脑体积与性别间差异有统计学意义(p<0.05),男性的脑体积要大于女性。脑体积在各年龄段之间差异无统计学意义( p>0.05)。结论头颅MRI 3D可以提供更准确的大脑容积定量,为各种相关疾病的临床诊断和治疗方案的制定提供客观依据。%Objective To measure the brain volume in normal Chinese , try to explore the relationship Methods 140 volunteers were examined with 3D T1 weighted images to obtain the between that with gender and age . whole brain image .The volume of whole brain was calculated on AW 4.1 workstation in semi-auto manner .Data of whole brain volume were analyzed in different gender and age with test and variance analysis .Results Volumes of the whole brain (The 95%confidence interval) were 1480.15±141.04 cm3 for male and 1322.91±110.11cm3 for . There was significant statistical correlation between whole brain volume and gender ( p0.05).Conclusion Whole brain MRI3D can provide quantitative brain volume more accurately , and provide objective basis for clinical diagnosis and treatment of various diseases .

  2. Diffusion, confusion and functional MRI

    International Nuclear Information System (INIS)

    Diffusion MRI has been introduced in 1985 and has had a very successful life on its own. While it has become a standard for imaging stroke and white matter disorders, the borders between diffusion MRI and the general field of fMRI have always remained fuzzy. First, diffusion MRI has been used to obtain images of brain function, based on the idea that diffusion MRI could also be made sensitive to blood flow, through the intra-voxel incoherent motion (IVIM) concept. Second, the IVIM concept helped better understand the contribution from different vasculature components to the BOLD fMRI signal. Third, it has been shown recently that a genuine fMRI signal can be obtained with diffusion MRI. This 'DfMRI' signal is notably different from the BOLD fMRI signal, especially for its much faster response to brain activation both at onset and offset, which points out to structural changes in the neural tissues, perhaps such as cell swelling, occurring in activated neural tissue. This short article reviews the major steps which have paved the way for this exciting development, underlying how technical progress with MRI equipment has each time been instrumental to expand the horizon of diffusion MRI toward the field of fMRI. (authors)

  3. Ultrasound- and MRI-Guided Prostate Biopsy

    Science.gov (United States)

    ... Index A-Z Ultrasound- and MRI-Guided Prostate Biopsy Ultrasound- and MRI-guided prostate biopsy uses imaging ... Biopsy? What is Ultrasound- and MRI-guided Prostate Biopsy? Ultrasound- and MRI-guided prostate biopsies are performed ...

  4. MRI Physics Workshop:

    Directory of Open Access Journals (Sweden)

    Daryoush Saedi

    2009-01-01

    Full Text Available Accurate knowledge of the basic principle of imaging physics helps better understanding of normal anatomy and pathological imaging findings of the diseases."n"n This is more necessary in advanced imaging techniques like MRI because of the complexity of the basic physics of the technique. In basic MRI physics workshop, we discuss about this technique from the primary concepts. The content is very simplified and is showed by slides, animation and easy pictures for better understanding. In the beginning of the lecture, the structure of atoms and their magnetic characteristics are explained and then step by step, we learn how to use this character to produce signal and usages of it to make an image. Also basic pulse sequence will be explained subsequently. This workshop is recommended for all radiologists, residents of radiology, technologists and anyone who wants to know more about MRI.    

  5. MRI in gout

    International Nuclear Information System (INIS)

    The appearance of gouty tophus in magnetic resonance imaging (MRI) is characteristic. On T1- and T2-weighted SE images, the signal intensity of tophaceous lesions is similar to that of muscles. According to the histology, T2-weighted SE images demonstrate extremely hyperintense signals, which reflect the high protein content in the amorpheous center of the tophus. The microscopic urate crystals deposited there have no MRI signal and are of no further diagnostic impact. Vascularized granulation tissue surrounding the tophus center enhance after intervenous application of contrast agents (Gadolinium). The inflammed tophus is associated with local edema, causing high signal intensity. MRI is superior to plain radiography for early detection of intraosseous tophi. Involvement of anatomical structures such as ligaments and tendons can be evaluated sufficiently. For peripheral joints, axial slice orientation is most helpful. (orig.)

  6. Fetal MRI in experimental tracheal occlusion

    International Nuclear Information System (INIS)

    Congenital diaphragmatic hernia (CDH) is associated with a high mortality, which is mainly due to pulmonary hypoplasia and secondary pulmonary hypertension. In severely affected fetuses, tracheal occlusion (TO) is performed prenatally to reverse pulmonary hypoplasia, because TO leads to accelerated lung growth. Prenatal imaging is important to identify fetuses with pulmonary hypoplasia, to diagnose high-risk fetuses who would benefit from TO, and to monitor the effect of TO after surgery. In fetal imaging, ultrasound (US) is the method of choice, because it is widely available, less expensive, and less time-consuming to perform than magnetic resonance imaging (MRI). However, there are some limitations for US in the evaluation of CDH fetuses. In those cases, MRI is helpful because of a better tissue contrast between liver and lung, which enables evaluation of liver herniation for the diagnosis of a high-risk fetus. MRI provides the ability to determine absolute lung volumes to detect lung hypoplasia. In fetal sheep with normal and hyperplastic lungs after TO, lung growth was assessed on the basis of cross-sectional US measurements, after initial lung volume determination by MRI. To monitor fetal lung growth after prenatal TO, both MRI and US seem to be useful methods

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    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 ...

  8. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... or cause problems during an MRI exam. Nephrogenic systemic fibrosis is currently a recognized, but rare, complication ... Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  9. 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; however, older ... MRI units may not provide this same image quality. Certain types of exams cannot be performed using ...

  10. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... MRI an invaluable tool in early diagnosis and evaluation of many conditions, including tumors. MRI enables the ... physicians with expertise in several radiologic areas. Outside links: For the convenience of our users, RadiologyInfo .org ...

  11. 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 ...

  12. 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 ... can help physicians evaluate the structures of the brain and can also provide functional information (fMRI) in ...

  13. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... about pregnancy and MRI. If you have claustrophobia (fear of enclosed spaces) or anxiety, you may want ... MRI can detect stroke at a very early stage by mapping the motion of water molecules in ...

  14. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... Magnetic resonance imaging (MRI) is a noninvasive medical test that physicians use to diagnose and treat medical ... CD. Currently, MRI is the most sensitive imaging test of the head (particularly the brain) in routine ...

  15. 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 ...

  16. Magnetic Resonance Imaging (MRI) -- Head

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

  17. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... during MRI, but this is rarely a problem. Tooth fillings and braces usually are not affected by ... Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic Resonance Imaging ( ...

  18. Magnetic Resonance Imaging (MRI) -- Head

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    Full Text Available ... News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) ... conditions such as: brain tumors stroke infections developmental anomalies hydrocephalus — dilatation of fluid spaces within the brain ( ...

  19. MRI of vaginal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, C. [Department of Radiology, Birmingham Women' s Hospital, Birmingham (United Kingdom)]. E-mail: carolina.lopez@bwhct.nhs.uk; Balogun, M. [Department of Radiology, Birmingham Women' s Hospital, Birmingham (United Kingdom); Ganesan, R. [Department of Histopathology, Birmingham Women' s Hospital, Birmingham (United Kingdom); Olliff, J.F. [University Hospital Birmingham, Birmingham (United Kingdom)

    2005-06-01

    Magnetic resonance imaging (MRI) has become an important part of the assessment of suspected vaginal pathology. This pictorial review demonstrates the MRI features and some of the histopathological findings of a variety of vaginal conditions. These may be congenital (total vaginal agenesis, partial vaginal agenesis, longitudinal vaginal septum, transverse vaginal septum), benign (Bartholin's cyst, diffuse vaginal inflammation, invasive endometriosis, ureterovaginal fistula, post-surgical appearances with the formation of a neovagina and adhesions) or malignant, usually due to extension or recurrence from another pelvic malignancy. In this paper, examples of the above are described and illustrated together with examples of the much rarer primary vaginal malignancies.

  20. Cerebral activity mapped by functional MRI

    International Nuclear Information System (INIS)

    Functional magnetic resonance imaging (fMRI) is a method to noninvasively measure the changes in cerebral activation during sensitive, cognitive or motor activity. fMRI detects activity by subtraction of states of activity and rest. During activity the signal is increased presumably due to a decrease of deoxyhemoglobin in the capillary and venous structures. Using a full field visual stimulation by flashlight goggles, a signal increase of 3% was detected in the primary visual cortex (V1). Different sequences and postprocessing algorythms will be discussed. Data from the primary cortical areas suggest a high reproducability of the experiments. Successfull experiments highly depend on cooperation of subjects. Despite success in experiments fMRI still has to be established for clinical purposes. (orig.)

  1. Tracking brain arousal fluctuations with fMRI.

    Science.gov (United States)

    Chang, Catie; Leopold, David A; Schölvinck, Marieke Louise; Mandelkow, Hendrik; Picchioni, Dante; Liu, Xiao; Ye, Frank Q; Turchi, Janita N; Duyn, Jeff H

    2016-04-19

    Changes in brain activity accompanying shifts in vigilance and arousal can interfere with the study of other intrinsic and task-evoked characteristics of brain function. However, the difficulty of tracking and modeling the arousal state during functional MRI (fMRI) typically precludes the assessment of arousal-dependent influences on fMRI signals. Here we combine fMRI, electrophysiology, and the monitoring of eyelid behavior to demonstrate an approach for tracking continuous variations in arousal level from fMRI data. We first characterize the spatial distribution of fMRI signal fluctuations that track a measure of behavioral arousal; taking this pattern as a template, and using the local field potential as a simultaneous and independent measure of cortical activity, we observe that the time-varying expression level of this template in fMRI data provides a close approximation of electrophysiological arousal. We discuss the potential benefit of these findings for increasing the sensitivity of fMRI as a cognitive and clinical biomarker. PMID:27051064

  2. Tracking brain arousal fluctuations with fMRI

    Science.gov (United States)

    Chang, Catie; Leopold, David A.; Schölvinck, Marieke Louise; Mandelkow, Hendrik; Picchioni, Dante; Liu, Xiao; Ye, Frank Q.; Turchi, Janita N.; Duyn, Jeff H.

    2016-01-01

    Changes in brain activity accompanying shifts in vigilance and arousal can interfere with the study of other intrinsic and task-evoked characteristics of brain function. However, the difficulty of tracking and modeling the arousal state during functional MRI (fMRI) typically precludes the assessment of arousal-dependent influences on fMRI signals. Here we combine fMRI, electrophysiology, and the monitoring of eyelid behavior to demonstrate an approach for tracking continuous variations in arousal level from fMRI data. We first characterize the spatial distribution of fMRI signal fluctuations that track a measure of behavioral arousal; taking this pattern as a template, and using the local field potential as a simultaneous and independent measure of cortical activity, we observe that the time-varying expression level of this template in fMRI data provides a close approximation of electrophysiological arousal. We discuss the potential benefit of these findings for increasing the sensitivity of fMRI as a cognitive and clinical biomarker. PMID:27051064

  3. MRI evaluation of tuberous sclerosis

    International Nuclear Information System (INIS)

    The authors present four cases of tuberous sclerosis examined with MRI. The patho-anatomic aspects are reviewed and analysed with respect to MRI data. MRI appears superior to the CT particularly for imaging of cortical tubers, cystic lesions, and heterotopic clusters; these last two features were never described with MRI before. Here is also presented the second progressive case of giant intracranial aneurysm associated with tuberous sclerosis. (orig.)

  4. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging technique that does not involve exposure to ionizing radiation. MRI can help physicians evaluate the structures of the brain and can also provide functional information (fMRI) in selected cases. MR images of ...

  5. MRI of intact plants

    NARCIS (Netherlands)

    As, van H.; Scheenen, T.; Vergeldt, F.J.

    2009-01-01

    Nuclear magnetic resonance imaging (MRI) is a non-destructive and non-invasive technique that can be used to acquire two- or even three-dimensional images of intact plants. The information within the images can be manipulated and used to study the dynamics of plant water relations and water transpor

  6. Cardiac MRI tagging

    International Nuclear Information System (INIS)

    Cardiac MRI tagging is an original technique based upon the perturbation of the magnetization of determined regions of the myocardium (tags). The motion of the tags accurately reflects the deformation of the underlying tissue. Data analysis requires special techniques to reconstruct the 3D motion of the heart, and to evaluate the myocardial strain, locally and throughout the whole heart. (authors)

  7. MRI of intact plants.

    NARCIS (Netherlands)

    As, H. van; Scheenen, T.W.J.; Vergeldt, F.J.

    2009-01-01

    Nuclear magnetic resonance imaging (MRI) is a non-destructive and non-invasive technique that can be used to acquire two- or even three-dimensional images of intact plants. The information within the images can be manipulated and used to study the dynamics of plant water relations and water transpor

  8. MRI and interventions

    Institute of Scientific and Technical Information of China (English)

    Roberto Blanco Sequeiros

    2002-01-01

    @@ Interventional radiology was started not long after the discovery of X - rays. Interventions started as image guided biopsies and angiographies early this century, later emerged computed tomography (CT) and ultrasound-guided interventions in the 1970s and ultimately the magnetic resonance imaging(MRI) guided interventions at the 1980s.

  9. MRI in decompression illness

    International Nuclear Information System (INIS)

    We report a case of decompression illness in which the patient developed paraparesis during scuba diving after rapid ascent. MRI of the spine revealed a focal intramedullary lesion consistent with the symptoms. The pathophysiological and radiological aspects of spinal decompression illness are discussed. (orig.)

  10. Accuracy of MRI for estimating residual tumor size after neoadjuvant chemotherapy in locally advanced breast cancer: Relation to response patterns on MRI

    International Nuclear Information System (INIS)

    Background. This study evaluated the accuracy of magnetic resonance imaging (MRI) for estimating residual tumor size after neoadjuvant chemotherapy in patients with locally advanced breast cancer and assessed whether the tumor pattern on MRI after chemotherapy influenced the accuracy of the MRI measurement of the residual tumor size. Patients and methods. Fifty patients who received neoadjuvant chemotherapy with doxorubicin and docetaxel for locally advanced breast cancer were evaluated with MRI before and after chemotherapy. We compared the residual tumor size measured by MRI with the pathologically determined size and investigated the influence of the residual tumor pattern on MRI (shrinkage, nest or rim, and mixed) and pathologic characteristics on the accuracy of the MRI measurement. Results. The correlation coefficient between the residual tumor sizes determined by MRI and by pathology was 0.645. The MRI measurement agreed with the pathologically determined size in 36 patients (72%) and disagreed in 14 patients (28%), overestimating the size in 13 (26%) and underestimating the size in one (2%). Disagreement appeared to be more frequent in the cases showing a nest or rim pattern than in those exhibiting a shrinkage pattern, although this was not statistically significant (p=0.119). Conclusions. MRI is an accurate method for predicting the extent of residual tumor after neoadjuvant chemotherapy; however, it may overestimate the residual disease, especially in cases showing a nest or rim tumor pattern and in those having combined lesions with ductal carcinoma in situ or multiple scattered nodules after neoadjuvant chemotherapy

  11. Accuracy of MRI for estimating residual tumor size after neoadjuvant chemotherapy in locally advanced breast cancer: Relation to response patterns on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Jung; Im, Young-Hyuck [Div. of Hematology/Oncology, Dept. of Medic ine, Samsung Medical Center, Sungkyunkwan Univ. School of Medicine, Suwon (Korea); Han, Boo-Kyung [Dept. of Radiology and Center for Imaging Science, Samsung Medi cal Center, Sungkyunkwan Univ. School of Medicine, Suwon (KR)] (and others)

    2007-10-15

    Background. This study evaluated the accuracy of magnetic resonance imaging (MRI) for estimating residual tumor size after neoadjuvant chemotherapy in patients with locally advanced breast cancer and assessed whether the tumor pattern on MRI after chemotherapy influenced the accuracy of the MRI measurement of the residual tumor size. Patients and methods. Fifty patients who received neoadjuvant chemotherapy with doxorubicin and docetaxel for locally advanced breast cancer were evaluated with MRI before and after chemotherapy. We compared the residual tumor size measured by MRI with the pathologically determined size and investigated the influence of the residual tumor pattern on MRI (shrinkage, nest or rim, and mixed) and pathologic characteristics on the accuracy of the MRI measurement. Results. The correlation coefficient between the residual tumor sizes determined by MRI and by pathology was 0.645. The MRI measurement agreed with the pathologically determined size in 36 patients (72%) and disagreed in 14 patients (28%), overestimating the size in 13 (26%) and underestimating the size in one (2%). Disagreement appeared to be more frequent in the cases showing a nest or rim pattern than in those exhibiting a shrinkage pattern, although this was not statistically significant (p=0.119). Conclusions. MRI is an accurate method for predicting the extent of residual tumor after neoadjuvant chemotherapy; however, it may overestimate the residual disease, especially in cases showing a nest or rim tumor pattern and in those having combined lesions with ductal carcinoma in situ or multiple scattered nodules after neoadjuvant chemotherapy.

  12. Diagnosis of acute stroke by MRI and biomarker

    International Nuclear Information System (INIS)

    Stroke Care Unit (SCU) in Tokushima University Hospital has been opened since November 1999. Patients with acute stroke in SCU were diagnosed by stroke MRI and biomarker immediately after their admission. Diffusion MRI could diagnose the ultra-acute ischemic and hemorrhagic lesion except brainstem ischemic lesion within 3 hrs after onset. Diffusion-Perfusion mismatch was useful to indicate intra-arterial thrombolytic therapy. 3T-MRI was introduced since March 2004, and it can measured functional MR spectroscopy and tractography more quickly compared to 1. 5T-MRI. Plasma oxidized low density lipoprotein (LDL) in patients with acute cerebral infarction was significantly higher than that in healthy control and it became peak level during 3-5 day after stroke onset. In conclusion, stroke MRI and plasma oxidized LDL are useful diagnostic tools for acute stroke. (author)

  13. High-quality breast MRI.

    Science.gov (United States)

    Hendrick, R Edward

    2014-05-01

    Breast magnetic resonance imaging (MRI) demands the competing factors of high spatial resolution, good temporal resolution, high signal-to-noise ratios, and complete bilateral breast coverage. Achieving these competing factors requires modern MRI equipment with high magnetic field strength and homogeneity, high maximum gradient strength with short rise times, dedicated multichannel bilateral breast coils with prone patient positioning, and 3D (volume) gradient-echo MRI pulse sequences with short TR, short TE, high spatial resolution, and reasonably short acquisition times. This article discusses the equipment and pulse sequences needed to achieve high-quality breast MRI and summarizes requirements of the ACR Breast MRI Accreditation Program. PMID:24792656

  14. The impact of reliable prebolus T{sub 1} measurements or a fixed T{sub 1} value in the assessment of glioma patients with dynamic contrast enhancing MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, Anna [Aarhus University Hospital, Dept. of Neuroradiology, Aarhus (Denmark); Aarhus University, Center of Functionally Integrative Neuroscience, Aarhus (Denmark); Mouridsen, Kim; Mikkelsen, Irene Klaerke [Aarhus University, Center of Functionally Integrative Neuroscience, Aarhus (Denmark)

    2015-03-06

    Accurate quantification of hemodynamic parameters using dynamic contrast enhanced (DCE) MRI requires a measurement of tissue T{sub 1} prior to contrast injection (T{sub 1}). We evaluate (i) T{sub 1} estimation using the variable flip angle (VFA) and the saturation recovery (SR) techniques and (ii) investigate if accurate estimation of DCE parameters outperform a time-saving approach with a predefined T{sub 1} value when differentiating high- from low-grade gliomas. The accuracy and precision of T{sub 1} measurements, acquired by VFA and SR, were investigated by computer simulations and in glioma patients using an equivalence test (p > 0.05 showing significant difference). The permeability measure, K{sub trans}, cerebral blood flow (CBF), and - volume, V{sub p}, were calculated in 42 glioma patients, using fixed T{sub 1} of 1500 ms or an individual T{sub 1} measurement, using SR. The areas under the receiver operating characteristic curves (AUCs) were used as measures for accuracy to differentiate tumor grade. The T{sub 1} values obtained by VFA showed larger variation compared to those obtained using SR both in the digital phantom and the human data (p > 0.05). Although a fixed T{sub 1} introduced a bias into the DCE calculation, this had only minor impact on the accuracy differentiating high-grade from low-grade gliomas, (AUC{sub fix} = 0.906 and AUC{sub ind} = 0.884 for K{sub trans}; AUC{sub fix} = 0.863 and AUC{sub ind} = 0.856 for V{sub p;} p for AUC comparison > 0.05). T{sub 1} measurements by VFA were less precise, and the SR method is preferable, when accurate parameter estimation is required. Semiquantitative DCE values, based on predefined T{sub 1} values, were sufficient to perform tumor grading in our study. (orig.)

  15. Morton neuroma: MRI diagnostic value

    International Nuclear Information System (INIS)

    Objective: To evaluate the diagnostic value of MRI in Morton's Neuroma (MN). Material and methods: 23 patients with clinical diagnosis of MN were examined under two different protocols, with a 1.5 T Magnet. 1) T1, FSET2, FIR, T1 with contrast enhancement and fat suppression; 2) T1, FSET2, FIR without contrast enhancement (i.v. Gadolinium). Results: In the first group MN was found in 7 patients. In the second group 14 patients were studied, 7 with positive MR for neuroma, and 9 with negative MR. 6 were true-negative and 3 were false-negative. The Fisher Test between both groups was p < 0.05. Conclusion: MRI is effective for the diagnosis of Morton neuroma. The use of gadolinium and fat suppression significantly improved the detection of Morton neuroma, allowing better measurements of the lesion. These findings do not correlate with previous papers that do not encourage the use of i.v. Gadolinium. (author)

  16. ILEAL CROHN'S DISEASE: MRI WITH ENDOSCOPIC CORRELATION

    OpenAIRE

    Gallego, José C.; Echarri, Ana I.; Porta, Ana; Ollero, Virginia

    2011-01-01

    Abstract Purpose To evaluate activity staging of Crohn's disease (CD) measured with MR-enterography using ileoscopy as reference standard.Materials and methods: A prospective study was made of 61 patients with CD. All patients underwent MR-enterography and ileoscopy. MRI activity was measured by means of an ad hoc developed score, as well as by analysis of the imaging findings, and was compared with the SES-CD score obtained via ileoscopy. Examinations were performed usi...

  17. Ileal Crohn's disease: MRI with endoscopic correlation

    International Nuclear Information System (INIS)

    Purpose: To evaluate activity staging of Crohn's disease (CD) measured with MR-enterography using ileoscopy as reference standard. Materials and methods: A prospective study was made of 61 patients with CD. All patients underwent MR-enterography and ileoscopy. MRI activity was measured by means of an ad hoc developed score, as well as by analysis of the imaging findings, and was compared with the SES-CD score obtained via ileoscopy. Examinations were performed using a 1.0 T scanner. Results: MRI score discriminates between active and inactive disease with an area under the ROC curve of 0.941. Overall correlation with the standard reference SES-CD score was moderate to strong (Spearman's r = 0.62 p < 0.001). Agreement between both methods in staging patients with ileal CD as inactive, mild or moderate to severe was good (Cohen's κ = 0.60). Differences in means of the MRI activity scores of the three groups showed statistical significance (p < 0.01). Conclusions: The MRI score is a reliable predictor of activity in ileal CD and can stage patients in a way comparable to endoscopy. 1.0 T scans are valid for performing radiological evaluation of ileal Crohn's disease.

  18. MRI of the shoulder

    Energy Technology Data Exchange (ETDEWEB)

    Vahlensieck, M.

    2000-02-01

    Shoulder imaging is one of the major applications in musculoskeletal MRI. In order to analyze the images it is important to keep informed about anatomical and pathological findings and publications. In this article MRI technique, anatomy and pathology is reviewed. Technical considerations about MR sequences and examination strategy are only shortly discussed with emphasis on turbo spin echo and short T1 inversion recovery imaging. Basic anatomy as well as recent findings, including macroscopic aspects of the supraspinatus fat pad, composition of the supraspinatus muscle belly, and variability of the glenohumeral ligaments or coracoid ligament, are presented. Basic pathological conditions are described in detail, e. g. instability particularly problems in differentiating the various subtypes of labral pathology. Rotator cuff diseases are elucidated with emphasis on some rarer entities such as subscapularis calcifying tendinitis, coracoid impingement, chronic bursitis producing the double-line sign, prominent coraco-acromial ligament and the impingement due to an inflamed os acromiale. (orig.)

  19. MRI of the shoulder

    International Nuclear Information System (INIS)

    Shoulder imaging is one of the major applications in musculoskeletal MRI. In order to analyze the images it is important to keep informed about anatomical and pathological findings and publications. In this article MRI technique, anatomy and pathology is reviewed. Technical considerations about MR sequences and examination strategy are only shortly discussed with emphasis on turbo spin echo and short T1 inversion recovery imaging. Basic anatomy as well as recent findings, including macroscopic aspects of the supraspinatus fat pad, composition of the supraspinatus muscle belly, and variability of the glenohumeral ligaments or coracoid ligament, are presented. Basic pathological conditions are described in detail, e. g. instability particularly problems in differentiating the various subtypes of labral pathology. Rotator cuff diseases are elucidated with emphasis on some rarer entities such as subscapularis calcifying tendinitis, coracoid impingement, chronic bursitis producing the double-line sign, prominent coraco-acromial ligament and the impingement due to an inflamed os acromiale. (orig.)

  20. The impact of reliable pre-bolus T1 measurements or a fixed T1 value in the assessment of glioma patients with Dynamic Contrast Enhancing MRI

    DEFF Research Database (Denmark)

    Tietze, Anna; Mouridsen, Kim; Mikkelsen, Irene Klærke

    2015-01-01

    to differentiate tumor grade. Results: The T1 values obtained by VFA showed larger variation compared to those obtained using SR both in the digital phantom and the human data (p > 0.05). Although a fixed T1 introduced a bias into the DCE calculation, this had only minor impact on the accuracy......) investigate if accurate estimation of DCE parameters outperform a time-saving approach with a pre-defined T1 value when differentiating high- from low-grade gliomas. Methods: (i) The accuracy and precision of T1 measurements, acquired by VFA and SR was investigated by computer simulations and in glioma...... patients using an equivalence test (p > 0.05 showing significant difference). (ii) Ktrans, CBF, and Vp were calculated in 42 glioma patients using fixed T1 of 1500ms or an individual T1 measured using SR. The areas under the receiver operating characteristic curves (AUC) were used as measure for accuracy...

  1. MRI of maxillary sinuses

    International Nuclear Information System (INIS)

    A mucous membrane of the maxillary sinus is clinically important in the dental fields. Magnetic resonance imaging (MRI) can demonstrate a mucous membrane because the mucosa contains rich free water. However, the morphology and location of the mucous membrane of normal maxillary sinuses have not been studied well by MRI. T2-weighted coronal images were obtained by spin echo technique in 40 normal volunteers. The eight maxillary sinuses were classified into four groups (Type 1∼IV) according to the morphology and also classified into five groups (Type a, b1, b2, b3, c) according to the location of the mucous membrane. Coronal images obtained at a standard angle of 77 degree to the Frankfort horizontal (FH) plane was the best for the evaluation of maxillary sinus because the image displayed the maximum cross-section of the maxillary sinus. In the normal cases, Type I (no high signal intensity) was observed in 20 sites, Type II (linear high signal intensity) in 48 sites, Type III (belt-like high signal intensity) in 11 sites and Type IV (mass-like high signal intensity) in 1 site. Type a (medial∼basal wall) was observed in 46 sites, Type b1 (medial wall alone) in 4 sites, Type b2 (basal wall alone) in 8 sites and Type c (entire wall) in 2 sites. Half of the cases showed the same findings bilaterally. Thus, MRI could demonstrate the morphology and location of the mucous membrane in the normal maxillary sinus so clearly that MRI was considered to be a useful diagnostic tool in the dento-maxillo-facial region. (author)

  2. [MRI in coma survivors].

    Science.gov (United States)

    Tshibanda, L; Vanhaudenhuyse, A; Bruno, M A; Boly, M; Soddu, A; Laureys, S; Moonen, G

    2009-01-01

    Traumatic and non-traumatic brain injured disorders of consciousness patients are still challenging for diagnosis, prognosis, ethical and socio-economic reasons. Currently, there remains a high rate of misdiagnosis of the vegetative state (Schnakers, et al. 2009). Recent advances in MRI techniques (diffusion tensor, magnetic resonance spectroscopy and functional imaging) provide data that could improve the diagnostic and prognostic evaluation and management of these patients. PMID:20085015

  3. Concordance between distributed EEG source localization and simultaneous EEG-fMRI studies of epileptic spikes.

    Science.gov (United States)

    Grova, C; Daunizeau, J; Kobayashi, E; Bagshaw, A P; Lina, J-M; Dubeau, F; Gotman, J

    2008-01-15

    In order to analyze where epileptic spikes are generated, we assessed the level of concordance between EEG source localization using distributed source models and simultaneous EEG-fMRI which measures the hemodynamic correlates of EEG activity. Data to be compared were first estimated on the same cortical surface and two comparison strategies were used: (1) MEM-concordance: a comparison between EEG sources localized with the Maximum Entropy on the Mean (MEM) method and fMRI clusters showing a significant hemodynamic response. Minimal geodesic distances between local extrema and overlap measurements between spatial extents of EEG sources and fMRI clusters were used to quantify MEM-concordance. (2) fMRI-relevance: estimation of the fMRI-relevance index alpha quantifying if sources located in an fMRI cluster could explain some scalp EEG data, when this fMRI cluster was used to constrain the EEG inverse problem. Combining MEM-concordance and fMRI-relevance (alpha) indexes, each fMRI cluster showing a significant hemodynamic response (pEEG data. Nine patients with focal epilepsy who underwent EEG-fMRI examination followed by EEG recording outside the scanner were selected for this study. Among the 62 fMRI clusters analyzed (7 patients), 15 (24%) found in 6 patients were highly concordant with EEG according to both MEM-concordance and fMRI-relevance. EEG concordance was found for 5 clusters (8%) according to alpha only, suggesting sources missed by the MEM. No concordance with EEG was found for 30 clusters (48%) and for 10 clusters (16%) alpha was significantly negative, suggesting EEG-fMRI discordance. We proposed two complementary strategies to assess and classify EEG-fMRI concordance. We showed that for most patients, part of the hemodynamic response to spikes was highly concordant with EEG sources, whereas other fMRI clusters in response to the same spikes were found distant or discordant with EEG sources. PMID:17945511

  4. Synergistic enhancement of iron oxide nanoparticle and gadolinium for dual-contrast MRI

    International Nuclear Information System (INIS)

    Highlights: ► MR contrast agents exert influence on T1 or T2 relaxation time of the surrounding tissue. ► Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. ► Dual contrast MRI enhances the delineation of tumor borders and small lesions. ► The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd3+. ► The effect of DC-MRI can also come from the distinct pharmacokinetic distribution of SPIO and Gd-DTPA. -- Abstract: Purpose: The use of MR contrast agents allows accurate diagnosis by exerting an influence on the longitudinal (T1) or transverse (T2) relaxation time of the surrounding tissue. In this study, we combined the use of iron oxide (IO) particles and nonspecific extracellular gadolinium chelate (Gd) in order to further improve the sensitivity and specificity of lesion detection. Procedures: With a 7-Tesla scanner, pre-contrasted, IO-enhanced and dual contrast agent enhanced MRIs were performed in phantom, normal animals, and animal models of lymph node tumor metastases and orthotopic brain tumor. For the dual-contrast (DC) MRI, we focused on the evaluation of T2 weighted DC MRI with IO administered first, then followed by the injection of a bolus of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Results: Based on the C/N ratios and MRI relaxometry, the synergistic effect of coordinated administration of Gd-DTPA and IO was observed and confirmed in phantom, normal liver and tumor models. At 30 min after administration of Feridex, Gd-DTPA further decreased T2 relaxation in liver immediately after the injection. Additional administration of Gd-DTPA also immediately increased the signal contrast between tumor and brain parenchyma and maximized the C/N ratio to −4.12 ± 0.71. Dual contrast MRI also enhanced the delineation of tumor borders and small lesions. Conclusions: DC-MRI will be helpful to improve diagnostic accuracy and decrease the threshold size for lesion

  5. Synergistic enhancement of iron oxide nanoparticle and gadolinium for dual-contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Huang, Xinglu [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Qian, Chunqi [Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Zhu, Lei [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Center for Molecular Imaging and Translational Medicine, School of Public Health, Xiamen University, Xiamen 361005 (China); Hida, Naoki [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Niu, Gang, E-mail: niug@mail.nih.gov [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States); Chen, Xiaoyuan, E-mail: shawn.chen@nih.gov [Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health - NIH, Bethesda, MD 20892 (United States)

    2012-09-07

    Highlights: Black-Right-Pointing-Pointer MR contrast agents exert influence on T{sub 1} or T{sub 2} relaxation time of the surrounding tissue. Black-Right-Pointing-Pointer Combined use of iron oxide and Gd-DTPA can improve the sensitivity/specificity of lesion detection. Black-Right-Pointing-Pointer Dual contrast MRI enhances the delineation of tumor borders and small lesions. Black-Right-Pointing-Pointer The effect of DC-MRI can come from the high paramagnetic susceptibility of Gd{sup 3+}. Black-Right-Pointing-Pointer The effect of DC-MRI can also come from the distinct pharmacokinetic distribution of SPIO and Gd-DTPA. -- Abstract: Purpose: The use of MR contrast agents allows accurate diagnosis by exerting an influence on the longitudinal (T{sub 1}) or transverse (T{sub 2}) relaxation time of the surrounding tissue. In this study, we combined the use of iron oxide (IO) particles and nonspecific extracellular gadolinium chelate (Gd) in order to further improve the sensitivity and specificity of lesion detection. Procedures: With a 7-Tesla scanner, pre-contrasted, IO-enhanced and dual contrast agent enhanced MRIs were performed in phantom, normal animals, and animal models of lymph node tumor metastases and orthotopic brain tumor. For the dual-contrast (DC) MRI, we focused on the evaluation of T{sub 2} weighted DC MRI with IO administered first, then followed by the injection of a bolus of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA). Results: Based on the C/N ratios and MRI relaxometry, the synergistic effect of coordinated administration of Gd-DTPA and IO was observed and confirmed in phantom, normal liver and tumor models. At 30 min after administration of Feridex, Gd-DTPA further decreased T{sub 2} relaxation in liver immediately after the injection. Additional administration of Gd-DTPA also immediately increased the signal contrast between tumor and brain parenchyma and maximized the C/N ratio to -4.12 {+-} 0.71. Dual contrast MRI also enhanced the

  6. Hippocampus, caudate nucleus and entorhinal cortex volumetric MRI measurements in discrimination between Alzheimer’s disease, mild cognitive impairment, and normal aging

    Directory of Open Access Journals (Sweden)

    Rasha Elshafey

    2014-06-01

    Conclusion: Semi-automated MR volumetric measurements can be used to determine atrophy in hippocampus, caudate nucleus and entorhinal cortex which aided in discrimination of healthy elderly control subjects from subjects with AD and MCI and predict clinical decline of MCI leading to increase the efficiency of clinical treatments, delay institutionalization and improve cognition and behavioral symptoms.

  7. Stereological Analysis of Liver Biopsy Histology Sections as a Reference Standard for Validating Non-Invasive Liver Fat Fraction Measurements by MRI

    Science.gov (United States)

    St. Pierre, Tim G.; House, Michael J.; Bangma, Sander J.; Pang, Wenjie; Bathgate, Andrew; Gan, Eng K.; Ayonrinde, Oyekoya T.; Bhathal, Prithi S.; Clouston, Andrew; Olynyk, John K.; Adams, Leon A.

    2016-01-01

    Background and Aims Validation of non-invasive methods of liver fat quantification requires a reference standard. However, using standard histopathology assessment of liver biopsies is problematical because of poor repeatability. We aimed to assess a stereological method of measuring volumetric liver fat fraction (VLFF) in liver biopsies and to use the method to validate a magnetic resonance imaging method for measurement of VLFF. Methods VLFFs were measured in 59 subjects (1) by three independent analysts using a stereological point counting technique combined with the Delesse principle on liver biopsy histological sections and (2) by three independent analysts using the HepaFat-Scan® technique on magnetic resonance images of the liver. Bland Altman statistics and intraclass correlation (IC) were used to assess the repeatability of each method and the bias between the methods of liver fat fraction measurement. Results Inter-analyst repeatability coefficients for the stereology and HepaFat-Scan® methods were 8.2 (95% CI 7.7–8.8)% and 2.4 (95% CI 2.2–2.5)% VLFF respectively. IC coefficients were 0.86 (95% CI 0.69–0.93) and 0.990 (95% CI 0.985–0.994) respectively. Small biases (≤3.4%) were observable between two pairs of analysts using stereology while no significant biases were observable between any of the three pairs of analysts using HepaFat-Scan®. A bias of 1.4±0.5% VLFF was observed between the HepaFat-Scan® method and the stereological method. Conclusions Repeatability of the stereological method is superior to the previously reported performance of assessment of hepatic steatosis by histopathologists and is a suitable reference standard for validating non-invasive methods of measurement of VLFF. PMID:27501242

  8. Solving transient problems in ultra-low-field MRI

    OpenAIRE

    Zevenhoven, Koos Cornelis Jacobus

    2011-01-01

    Magnetic resonance imaging (MRI) is widely used in clinical applications as well as in research. While the state of the art of MRI has developed towards using multiple-tesla magnetic fields, another approach has emerged, where the signal is measured in a magnetic field on the order of Earth's magnetic field (~ 100 µT). Such ultra-low-field (ULF) MRI is made possible by highly-sensitive magnetic-field sensor technology based on superconducting quantum interference devices (SQUIDs). For increas...

  9. MRI diagnosis of meningovascular neurosyphilis

    International Nuclear Information System (INIS)

    Objective: To evaluate the value and limitation of MRI in the diagnosis of meningovascular neurosyphilis. Methods: Five cases of neurosyphilis confirmed by clinical history/laboratory were examined with MRI (3 plain MRI, 2 enhanced MRI). The results of blood and CSF TPPA/RPR were positive and HIV was negative. Results: Abnormal signals were demonstrated in the temporal lobe in 3 cases, and infarction was revealed in the basal ganglion and periventricular white matter in another 2 cases. There was no marked contrast enhancement in the 2 cases. Conclusion: Meningovascular neurosyphilis has no characteristic features on MRI, but MRI is an effective method in delineating the size, range, and characters of neurosyphilis, and it is also an useful modality to follow-up after antibiotic therapy. (authors)

  10. Intra- and interobserver variability of MRI-based volume measurements of the hippocampus and amygdala using the manual ray-tracing method

    Energy Technology Data Exchange (ETDEWEB)

    Achten, E.; Deblaere, K.; Damme, F. van; Kunnen, M. [MR Department 1K12, University Hospital Gent (Belgium); Wagter, C. de [Department of Radiotherapy and Nuclear Medicine, University Hospital Gent (Belgium); Boon, P.; Reuck, J. de [Department of Neurology, University Hospital Gent (Belgium)

    1998-09-01

    We studied the intra- and interobserver variability of volume measurments of the hippocampus (HC) and the amygdala as applied to the detection of HC atrophy in patients with complex partial seizures (CPE), measuring the volumes of the HC and amygdala of 11 normal volunteers and 12 patients with presumed CPE, using the manual ray-tracing method. Two independent observers performed these measurements twice each using home-made software. The intra- and interobserver variability of the absolute volumes and of the normalised left-to-right volume differences ({delta}V) between the HC ({delta}V{sub HC}), the amygdala ({delta}V{sub A}) and the sum of both ({delta}V{sub HCA)} were assessed. In our mainly right-handed normals, the right HC and amygdala were on average 0.05 and 0.03 ml larger respectively than on the left. The interobserver variability for volume measurements in normal subjects was 1.80 ml for the HC and 0.82 ml for the amygdala, the intraobserver variability roughly one third of these values. The interobserver variability coefficient in normals was 3.6 % for {delta}V{sub HCA}, 4.7 % for {delta}V{sub HC} and 7.3 % for {delta}V{sub A}. The intraobserver variability coefficient was 3.4 % for {delta}V{sub HCA}, 4.2 % for {delta}V{sub HC} amd 5.6 % for {delta}V{sub A}. The variability in patients was the same for volume differences less than 5 % either side of the interval for normality, but was higher when large volume differences were encountered, is probably due to the lack of thresholding and/or normalisation. Cutoff values for lateralisation with the {delta}V were defined. No intra- or interobserver lateralisation differences were encountered with {delta}V{sub HCA} and {delta}V{sub HC}. From these observations we conclude that the manual ray-tracing method is a robust method for lateralisation in patients with TLE. Due to its higher variability, this method is less suited to measure absolute volumes. (orig.) (orig.) With 2 figs., 7 tabs., 23 refs.

  11. Intra- and interobserver variability of MRI-based volume measurements of the hippocampus and amygdala using the manual ray-tracing method

    International Nuclear Information System (INIS)

    We studied the intra- and interobserver variability of volume measurments of the hippocampus (HC) and the amygdala as applied to the detection of HC atrophy in patients with complex partial seizures (CPE), measuring the volumes of the HC and amygdala of 11 normal volunteers and 12 patients with presumed CPE, using the manual ray-tracing method. Two independent observers performed these measurements twice each using home-made software. The intra- and interobserver variability of the absolute volumes and of the normalised left-to-right volume differences (δV) between the HC (δVHC), the amygdala (δVA) and the sum of both (δVHCA) were assessed. In our mainly right-handed normals, the right HC and amygdala were on average 0.05 and 0.03 ml larger respectively than on the left. The interobserver variability for volume measurements in normal subjects was 1.80 ml for the HC and 0.82 ml for the amygdala, the intraobserver variability roughly one third of these values. The interobserver variability coefficient in normals was 3.6 % for δVHCA, 4.7 % for δVHC and 7.3 % for δVA. The intraobserver variability coefficient was 3.4 % for δVHCA, 4.2 % for δVHC amd 5.6 % for δVA. The variability in patients was the same for volume differences less than 5 % either side of the interval for normality, but was higher when large volume differences were encountered, is probably due to the lack of thresholding and/or normalisation. Cutoff values for lateralisation with the δV were defined. No intra- or interobserver lateralisation differences were encountered with δVHCA and δVHC. From these observations we conclude that the manual ray-tracing method is a robust method for lateralisation in patients with TLE. Due to its higher variability, this method is less suited to measure absolute volumes. (orig.) (orig.)

  12. 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.)

  13. Developing a multichannel temperature probe for interventional MRI.

    Science.gov (United States)

    Shankaranarayanan, A; Duerk, J L; Lewin, J S

    1998-01-01

    Interventional MRI (I-MRI) guided thermal tissue ablation has been used for a variety of interventional cancer therapies. These would be further facilitated by temperature-sensitive sequences on low magnetic field MR images. However, until these sequences have been reliably implemented at low fields, other methods of temperature measurement are required. This project describes the development of a low cost, reliable, MRI-compatible temperature sensor array useful at a temperature range from 37 degrees C to higher than 90 degrees C. The device uses a three-channel thermocouple sensor array connected to a variety of filtering and signal-conditioning electronics, analog-to-digital (A/D) converters, and personal computers. The sensors induce negligible field distortion. Similarly, no MRI-based measurement artifacts are observed. One-dimensional temperature profiles are generated with thermocouple signal linearization performed by the software. PMID:9500280

  14. MRI assessment program. Consensus statement on clinical efficacy of MRI

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    This consensus statement is largely based on the experience gained at the MRI units at the four hospitals which have operated scanners in the MRI program. It reflects the considered opinion of the radiologists responsible for the MRI services at those hospitals. Account has also been taken of relevant overseas data. This collection of opinion relates particularly to comparison with other imaging modalities. The specific comments will require further consideration as technical developments with MRI become available, additional experience is gained with gadolinium contrast material and additional data are obtained on the influence of MRI on patient management. MRI, at present, is used either to improve diagnostic accuracy when other tests are negative or equivocal, when there is strong clinical suspicion of disease, or to improve surgical or other management planning when the diagnosis known. In some situations (eg syringomyelia, congenital spinal disease, posterior fossa/cerebello-pontine angle tumours) it may entirely replace other tests (eg myelography, air contrast, CT) which are substantially less accurate and/or more invasive. In other situations (eg hemispheric brain tumours, lumbar disc protrusions) when other tests, such as CT, can be as accurate, MRI is not usually or initially indicated because it is currently more expensive and of limited availability. However, balanced against this is the fact that it does not expose the patient to potentially harmful ionising radiation. It is also stressed that MRI images depend on complex, widely variable and, as yet, incompletely understood parameters. There is concern that this may result in false positive diagnoses, especially where MRI is used alone as a screening test, or used as the initial test. For several reasons (availability, cost, medical and diagnostic efficacy), the specific comments on indications for MRI presented are based upon the assumption that MRI is a tertiary and complementary imaging examination

  15. MRI assessment program. Consensus statement on clinical efficacy of MRI

    International Nuclear Information System (INIS)

    This consensus statement is largely based on the experience gained at the MRI units at the four hospitals which have operated scanners in the MRI program. It reflects the considered opinion of the radiologists responsible for the MRI services at those hospitals. Account has also been taken of relevant overseas data. This collection of opinion relates particularly to comparison with other imaging modalities. The specific comments will require further consideration as technical developments with MRI become available, additional experience is gained with gadolinium contrast material and additional data are obtained on the influence of MRI on patient management. MRI, at present, is used either to improve diagnostic accuracy when other tests are negative or equivocal, when there is strong clinical suspicion of disease, or to improve surgical or other management planning when the diagnosis known. In some situations (eg syringomyelia, congenital spinal disease, posterior fossa/cerebello-pontine angle tumours) it may entirely replace other tests (eg myelography, air contrast, CT) which are substantially less accurate and/or more invasive. In other situations (eg hemispheric brain tumours, lumbar disc protrusions) when other tests, such as CT, can be as accurate, MRI is not usually or initially indicated because it is currently more expensive and of limited availability. However, balanced against this is the fact that it does not expose the patient to potentially harmful ionising radiation. It is also stressed that MRI images depend on complex, widely variable and, as yet, incompletely understood parameters. There is concern that this may result in false positive diagnoses, especially where MRI is used alone as a screening test, or used as the initial test. For several reasons (availability, cost, medical and diagnostic efficacy), the specific comments on indications for MRI presented are based upon the assumption that MRI is a tertiary and complementary imaging examination

  16. Quality assurance in functional MRI

    DEFF Research Database (Denmark)

    Liu, Thomas T; Glover, Gary H; Mueller, Bryon A;

    2015-01-01

    Over the past 20 years, functional magnetic resonance imaging (fMRI) has ben- efited greatly from improvements in MRI hardware and software. At the same time, fMRI researchers have pushed the technical limits of MRI systems and greatly in- fluenced the development of state-of-the-art systems...... imaging methods such as echo-planar imaging (EPI) or spiral acquisitions that can push the scanner hardware to its limits. High temporal stability sustained over the course of a scan session (up to 2 h) is required to obtain quality data within a single subject, sustained stability is required to obtain...

  17. MRI of the fetal abdomen

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) is an important diagnostic component for central nervous system and thoracic diseases during fetal development. Although ultrasound remains the method of choice for observing the fetus during pregnancy, fetal MRI is being increasingly used as an additional technique for the accurate diagnosis of abdominal diseases. Recent publications confirm the value of MRI in the diagnosis of fetal gastrointestinal tract and urogenital system diseases. The following report provides an overview of MRI-examination techniques for the most frequent diseases of the abdomen. (orig.)

  18. NMR, MRI, and spectroscopic MRI in inhomogeneous fields

    Science.gov (United States)

    Demas, Vasiliki; Pines, Alexander; Martin, Rachel W; Franck, John; Reimer, Jeffrey A

    2013-12-24

    A method for locally creating effectively homogeneous or "clean" magnetic field gradients (of high uniformity) for imaging (with NMR, MRI, or spectroscopic MRI) both in in-situ and ex-situ systems with high degrees of inhomogeneous field strength. THe method of imaging comprises: a) providing a functional approximation of an inhomogeneous static magnetic field strength B.sub.0({right arrow over (r)}) at a spatial position {right arrow over (r)}; b) providing a temporal functional approximation of {right arrow over (G)}.sub.shim(t) with i basis functions and j variables for each basis function, resulting in v.sub.ij variables; c) providing a measured value .OMEGA., which is an temporally accumulated dephasing due to the inhomogeneities of B.sub.0({right arrow over(r)}); and d) minimizing a difference in the local dephasing angle .phi.({right arrow over (r)},t)=.gamma..intg..sub.0.sup.t{square root over (|{right arrow over (B)}.sub.1({right arrow over (r)},t')|.sup.2+({right arrow over (r)}{right arrow over (G)}.sub.shimG.sub.shim(t')+.parallel.{right arrow over (B)}.sub.0({right arrow over (r)}).parallel..DELTA..omega.({right arrow over (r)},t'/.gamma/).sup.2)}dt'-.OMEGA. by varying the v.sub.ij variables to form a set of minimized v.sub.ij variables. The method requires calibration of the static fields prior to minimization, but may thereafter be implemented without such calibration, may be used in open or closed systems, and potentially portable systems.

  19. Application of ADC measurement in characterization of renal cell carcinomas with different pathological types and grades by 3.0 T diffusion-weighted MRI

    International Nuclear Information System (INIS)

    Purpose: To test the feasibility of apparent diffusion coefficient (ADC) value obtained with 3.0 T diffusion-weighted imaging (DWI) in the characterization of renal cell carcinomas (RCC) with different pathological subtypes and grades. Materials and methods: A total of 137 patients who were diagnosed with RCC and underwent DWI were included in this study. The diagnosis was confirmed by pathological examination of surgical specimens. Images of DWI were obtained with b values of 0 and 800 s/mm2. The ADC values in the solid area of tumors and in the corresponding regions of contralateral normal renal parenchyma were measured and analyzed statistically. Results: The mean ADC value was significantly lower in RCC (1.381 ± 0.444 × 10−3 mm2/s) than in normal renal parenchyma (2.232 ± 0.221 × 10−3 mm2/s) (P < 0.001). The ADC value was also statistically different between clear cell RCC (CCRCC) and non-CCRCC, and between different grades of CCRCC except grade I vs II and grade III vs IV. Conclusion: ADC measurement on 3.0 T DWI provides useful information in diagnostic work-up of RCC in terms of differentiation of RCC and normal renal parenchyma, and characterization of RCC with different pathological subtypes and grades.

  20. Application of ADC measurement in characterization of renal cell carcinomas with different pathological types and grades by 3.0 T diffusion-weighted MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaoduo, E-mail: yxd98@yahoo.com.cn [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Lin, Meng, E-mail: linmeng77xp@yahoo.com.cn [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Ouyang, Han, E-mail: hbybj@sohu.com [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Zhou, Chunwu, E-mail: cjr.zhouchunwu@163.vip.com [Department of Diagnostic Radiology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China); Zhang, Hongtu, E-mail: zhanghongtu1010@yahoo.com.cn [Department of Pathology, Cancer Institute and Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing (China)

    2012-11-15

    Purpose: To test the feasibility of apparent diffusion coefficient (ADC) value obtained with 3.0 T diffusion-weighted imaging (DWI) in the characterization of renal cell carcinomas (RCC) with different pathological subtypes and grades. Materials and methods: A total of 137 patients who were diagnosed with RCC and underwent DWI were included in this study. The diagnosis was confirmed by pathological examination of surgical specimens. Images of DWI were obtained with b values of 0 and 800 s/mm{sup 2}. The ADC values in the solid area of tumors and in the corresponding regions of contralateral normal renal parenchyma were measured and analyzed statistically. Results: The mean ADC value was significantly lower in RCC (1.381 {+-} 0.444 Multiplication-Sign 10{sup -3} mm{sup 2}/s) than in normal renal parenchyma (2.232 {+-} 0.221 Multiplication-Sign 10{sup -3} mm{sup 2}/s) (P < 0.001). The ADC value was also statistically different between clear cell RCC (CCRCC) and non-CCRCC, and between different grades of CCRCC except grade I vs II and grade III vs IV. Conclusion: ADC measurement on 3.0 T DWI provides useful information in diagnostic work-up of RCC in terms of differentiation of RCC and normal renal parenchyma, and characterization of RCC with different pathological subtypes and grades.

  1. MRI determination of cardiac dimensions. 5

    International Nuclear Information System (INIS)

    MR images in cardiac function studies allow for precise alignment in reproducible axial planes, with excellent resolution and without areas of signal loss, so that highly accurate measurements can be made. This is important particularly in patients with regional functional deficits, in whom precise depiction of function in each myocardial region without overlap or signal 'drop-out' is critical. Also, MR tomograms make possible the elimination of geometric assumptions, which lead to errors when regional dysfunction is present, in assessment of ventricular volume and ejection fraction. The development of improved temporal resolution and motion display by cine MRI and, in particular, echo-planar techniques has made the measurement of function MRI a valuable clinical method. (author). 36 refs.; 7 figs.; 1 tab

  2. Anatomical analysis of human masseter using MRI

    International Nuclear Information System (INIS)

    To quantitatively elucidate individual variation in human masseter muscle, the cross sectional area of this muscle was measured in situ with MRI apparatus. The results were analyzed against age, body build and laterality in habitual mastication by bivariate correlation analysis. Materials included 52 healthy volunteers (26 males, 26 females). Right and left masseter areas and total cross sectional area of the face were measured in the same horizontal plane, and directly displayed on the console of the MRI apparatus. The areas of masseter muscles were not correlated with age or body build, but were positively correlated with the total cross sectional area of the face in the same horizontal plane. Because the left masseters tended to be larger than right, a method for evaluation of the relative size of each side of the messeters was established. This analysis revealed that the corrected dominance of the masseter corresponded, with high probability, to the habitual laterality in mastication. (author)

  3. Photo-magnetic Imaging: Resolving Optical Contrast at MRI resolution

    OpenAIRE

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

    2013-01-01

    In this paper, we establish the mathematical framework of a novel imaging technique, namely Photo-magnetic Imaging (PMI). PMI uses 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 optical contrast at MRI spatial resolution. The image reconstruction for PMI, using a finite element-based algorithm with iterative approach, is presented in...

  4. MRI for clinically suspected pediatric appendicitis: case interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Michael M.; Brian, James M.; Methratta, Sosamma T.; Hulse, Michael A.; Choudhary, Arabinda K.; Eggli, Kathleen D.; Boal, Danielle K.B. [Penn State Milton S. Hershey Medical Center, Division of Pediatric Radiology, Department of Radiology, Hershey, PA (United States)

    2014-05-15

    As utilization of MRI for clinically suspected pediatric appendicitis becomes more common, there will be increased focus on case interpretation. The purpose of this pictorial essay is to share our institution's case interpretation experience. MRI findings of appendicitis include appendicoliths, tip appendicitis, intraluminal fluid-debris level, pitfalls of size measurements, and complications including abscesses. The normal appendix and inguinal appendix are also discussed. (orig.)

  5. Anisotropic Smoothing Improves DT-MRI-Based Muscle Fiber Tractography

    OpenAIRE

    Buck, Amanda K. W.; Ding, Zhaohua; Elder, Christopher P; Towse, Theodore F.; Damon, Bruce M.

    2015-01-01

    Purpose To assess the effect of anisotropic smoothing on fiber tracking measures, including pennation angle, fiber tract length, and fiber tract number in the medial gastrocnemius (MG) muscle in healthy subjects using diffusion-weighted magnetic resonance imaging (DW-MRI). Materials and Methods 3T DW-MRI data were used for muscle fiber tractography in the MG of healthy subjects. Anisotropic smoothing was applied at three levels (5%, 10%, 15%), and pennation angle, tract length, fiber tract nu...

  6. Minimum Field Strength Simulator for Proton Density Weighted MRI.

    Directory of Open Access Journals (Sweden)

    Ziyue Wu

    Full Text Available To develop and evaluate a framework for simulating low-field proton-density weighted MRI acquisitions based on high-field acquisitions, which could be used to predict the minimum B0 field strength requirements for MRI techniques. This framework would be particularly useful in the evaluation of de-noising and constrained reconstruction techniques.Given MRI raw data, lower field MRI acquisitions can be simulated based on the signal and noise scaling with field strength. Certain assumptions are imposed for the simulation and their validity is discussed. A validation experiment was performed using a standard resolution phantom imaged at 0.35 T, 1.5 T, 3 T, and 7 T. This framework was then applied to two sample proton-density weighted MRI applications that demonstrated estimation of minimum field strength requirements: real-time upper airway imaging and liver proton-density fat fraction measurement.The phantom experiment showed good agreement between simulated and measured images. The SNR difference between simulated and measured was ≤ 8% for the 1.5T, 3T, and 7T cases which utilized scanners with the same geometry and from the same vendor. The measured SNR at 0.35T was 1.8- to 2.5-fold less than predicted likely due to unaccounted differences in the RF receive chain. The predicted minimum field strength requirements for the two sample applications were 0.2 T and 0.3 T, respectively.Under certain assumptions, low-field MRI acquisitions can be simulated from high-field MRI data. This enables prediction of the minimum field strength requirements for a broad range of MRI techniques.

  7. The application of Compressed Sensing for Longitudinal MRI

    CERN Document Server

    Weizman, Lior; Bashat, Dafna Ben

    2014-01-01

    Purpose: The mutual similarity of the follow-up scans in longitudinal studies is exploited on top of the well known sparse transform domains for rapid MRI by reducing the number of k-space measurements. Theory and Methods: A framework for adaptive Compressed Sensing (CS) MRI that exploits the redundancy of the acquired data in longitudinal studies is proposed. The baseline MR scan is utilized both in the sampling stage, with adaptive CS, and in the reconstruction stage, with weighted CS. In adaptive CS, k-space sampling locations are optimized such that the acquired data is focused on the change between the follow-up MRI and the former one. Weighted CS uses the locations of the nonzero coefficients in the sparse domains as a prior in the recovery process. Results: Experiments demonstrate that our longitudinal adaptive CS MRI (LACS-MRI) scheme provides reconstruction quality which outperforms traditional CS MRI for rapid MRI. Examples are shown on patients with brain tumors and demonstrate improved spatial res...

  8. 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.

  9. Iron shielded MRI optimization

    Science.gov (United States)

    Borghi, C. A.; Fabbri, M.

    1998-09-01

    The design of the main current systems of an actively shielded and of an iron shielded MRI device for nuclear resonance imaging, is considered. The model for the analysis of the magnetic induction produced by the current system, is based on the combination of a Boundary Element technique and of the integration of two Fredholm integral equations of the first and the second kind. The equivalent current magnetization model is used for the calculation of the magnetization produced by the iron shield. High field uniformity in a spherical region inside the device, and a low stray field in the neighborhood of the device are required. In order to meet the design requirements a multi-objective global minimization problem is solved. The minimization method is based on the combination of the filled function technique and the (1+1) evolution strategy algorithm. The multi-objective problem is treated by means of a penalty method. The actively shielded MRI system results to utilize larger amount of conductor and produce higher magnetic energy than the iron shield device. On veut étudier le projet du système des courants principaux d'un MRI à écran en fer et d'un MRI à écran actif. Le modèle d'analyse du champ magnétique produit par le système de courants est basé sur la combinaison d'une technique Boundary Element et de l'intégration de deux équations intégrales de Fredholm de première et de seconde sorte. On utilise pour calculer la magnétisation produite par l'écran en fer le modèle à cou rants de magné ti sa tion équivalents. On exige une élévation uniforme du champ dans une région sphérique au cœur de l'appareil et un bas champ magnétique dispersé à proximité de l'appareil. Dans le but de répondre aux impératifs du projet, on va résoudre un problème multiobjectif de minimisation globale. On utilise une technique de minimisation obtenue par la combinaison des méthodes “Filled Function” et “(1+1) Evolution Strategy”. Le probl

  10. MRI finding of hemangioblastomas

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seung Cheol; Oh, Min Cheol; Chung, Hwan Hoon; Seol, Hye Young; Lee, Nam Joon; Kim, Jung Hyuk [Korea University College of Medicine, Seoul (Korea, Republic of)

    1994-05-15

    The purpose of this study is to evaluate the findings of magnetic resonance imaging (MRI) of posterior fossa hemanangioblastoma and usefulness of contrast enhancement with Gd-DTPA. Seven patients with posterior fossa hemangioblastoma were studied with both pre- and post-enhanced MRI. The MR images were reviewed regarding the location, size, signal intensities of cysts and mural nodules, and their contrast enhancement pattern. Five tumors were located in cerebellar hemisphere, one in vermis, and one in posterior part of medulla. One patient with von Hippel-Lindau disease had a medullary hemangioblastoma with multiple pancreatic cysts. In 6 cases, the major portion of the tumor was cysts and had small mulkal nodules. The solid portion was relatively lange in one cases, cemprising half of the tumor cysts were oval shaped and their sized were 3-6.7 cm in diameter. In five cases(71%), septations were noted within the cysts. Cysts were isointense or slightly hyperintense on T1-weighted image and hyperintense on T2- weighted image compared with cerebrospinal fluid. Mural nodules were oval or rounded radiotherapy had better prognosis than those treated with radiotherapy alwas 0.5-2.5 cm in diameter. Mural nodules were isointense to gray matter. They were detected in five cases on T1-weighted images and one case on T2-weighted images. In two cases, vascular signal void area was noted in mural nodules. On contrast-enhanced T1-weighted images, all mural nodules were intensely enhanced. MRI provide to be a good diagnostic method to detect and characterize posterior fossa hemangioblastoma. The most common finding is Cystic posterior fossa lesion with enhancing mural nodule. Contrast enhancement is essential for specific diagnosis.

  11. Functional MRI and Attention Deficit Hyperactivity Disorder

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-12-01

    Full Text Available The Stroop effect, a measure for selective attention, on behavioral and brain activation of attention deficit hyperactivity disorder (ADHD children (9 boys, ages 9.8-14.5 years, off or on methylphenidate and 9 controls was studied using event-related functional magnetic resonance imaging (fMRI at the Institute of Mental Health, Peking University, Beijing, China, and other centers in China and at Harvard Medical School, Boston, MA, USA.

  12. MRI for the evaluation of pectus excavatum

    OpenAIRE

    Marcovici, Peter A.; LoSasso, Barry E.; Kruk, Peter; Dwek, Jerry R.

    2011-01-01

    Pectus excavatum, the most common congenital deformity of the anterior chest wall, is both a cosmetic and functional abnormality. The degree of abnormal chest wall deformity determines its functional effect, particularly its cardiac and pulmonary impact. Although CT scanning is the most widely used cross-sectional imaging technique used to measure the Haller index, the radiation exposure is reason to seek other alternatives. At our institution, we have introduced a rapid MRI technique for thi...

  13. CT and MRI of dementia disorders

    Energy Technology Data Exchange (ETDEWEB)

    Momoshima, Suketaka; Fujiwara, Hirokazu [Keio Univ., Tokyo (Japan). School of Medicine

    2002-06-01

    Imaging diagnosis plays a critical role in the initial evaluation of dementia disorders despite its limited specificity. The two major causes of dementia are neurodegenerative disorders including Alzheimer disease and diffuse vascular disorders, some of which show characteristic findings on CT and MRI. Although effective treatment is not yet available for most of these entities, there is possibility that early diagnosis by imaging could lead to preventive measures in future. Some illustrative cases of dementia diseases are demonstrated. (author)

  14. CT and MRI of dementia disorders

    International Nuclear Information System (INIS)

    Imaging diagnosis plays a critical role in the initial evaluation of dementia disorders despite its limited specificity. The two major causes of dementia are neurodegenerative disorders including Alzheimer disease and diffuse vascular disorders, some of which show characteristic findings on CT and MRI. Although effective treatment is not yet available for most of these entities, there is possibility that early diagnosis by imaging could lead to preventive measures in future. Some illustrative cases of dementia diseases are demonstrated. (author)

  15. Extended MRI findings of intersection syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Roger P.; Hatem, Stephen F.; Recht, Michael P. [Cleveland Clinic, Cleveland, OH (United States)

    2009-02-15

    The symptoms and physical findings of intersection syndrome have been well described in the clinical medical literature. However, the magnetic resonance imaging (MRI) findings in patients with intersection syndrome of the forearm have only recently been described in a small number of patients. We review our experience with imaging of intersection syndrome, describe previously unreported MRI findings, and emphasize modifications to MRI protocols for its evaluation. Institutional review board approval was obtained for this retrospective review of patients with MRI findings consistent with intersection syndrome of the forearm during the period from January 2004 to September 2006. Six patients were identified, three males and three females, with an average age of 39.3 years. The MRI examinations were reviewed to assess signal abnormalities within and adjacent to the first and second dorsal extensor tendon compartments (DETC): tendinosis, peritendinous edema or fluid, muscle edema, subcutaneous edema, and juxtacortical edema. The overall longitudinal extent of signal alterations was measured as well as the distance from Lister's tubercle to the crossover of the first and second DETC. Review of the MRIs showed increased intrasubstance tendon signal suggesting tendinosis in two of the six patients, peritendinous edema or fluid in all six patients, muscle edema in five of the six patients, and subcutaneous edema in three of the six patients. Juxtacortical edema was seen in one patient. Peritendinous edema or fluid extended distally beyond the radiocarpal joint in three of the six patients. The average distance from Lister's tubercle to the crossover of the first and second DETC was 3.95 cm, in keeping with recently published data. Intersection syndrome is an uncommon MRI diagnosis. In addition to the previously described MRI findings of edema adjacent to the first or second DETC, possibly with proximal extension and subcutaneous edema, we have identified

  16. The MRI characteristics of Hashimoto encephalopathy

    International Nuclear Information System (INIS)

    Objective: To study the MRI findings of HE and the pathological mechanism and to improve the diagnosis and differential diagnosis of HE. Methods: Five patients of HE diagnosed by clinical and laboratory examination were examined with conventional MRI scan. Additional DWI, MRA and enhancement MRI scan were performed on 3 patients in which abnormal findings was detected on the conventional MRI. The distribution of lesions and signal characteristics were analyzed. The ADC values of the lesions and of the contralateral non-lesion area were measured. Moreover, the possible pathological mechanisms of HE were discussed on the basis of changes of clinical and imaging manifestations in the two cases with serial clinical and MRI data. Results: Of 5 patients, brain abnormalities were found in 3 cases, which showed scattered spotted supratentorial white matter lesions of isointensity on T1WI and DWI, and high signal intensity on T2WI and fluid-attenuated inversion recovery (FLAIR). Meanwhile, multiple plaque-like lesions involving both white matter and gray matter were found, mainly located at the basal ganglia nuclei, hippocampus and cingulate cortex. The lesions demonstrated iso-or hypo-intensity on T1WI, and iso-or hyper-intensity on T2WI, FlAIR and DWI at the initial stage. No enhancement was found in these lesions and MRA disclosed no remarkable findings. The ADC value of the lesions [(0.449±0.092)×10-3 mm2/S] was decreased significantly compared with the contralateral noninvolved area [(0.838± 0.062)×10-3 mm2/s] at the early onset. In 2 cases with glucocorticoid therapy, together with symptom relief, MRI follow-up scan demonstrated the reduction of lesion volume, the signal change to hyperintensity on T1WI and hypo-intensity on DWI. The ADC of the lesions increased significantly. Conclusion: The MRI could be one of the effective tools for diagnosis, differential diagnosis, and judging the prognosis and therapeutic results of HE. Meanwhile, it may be a non

  17. Rabies, encephalomyelitis: MRI findings

    International Nuclear Information System (INIS)

    The authors present a 14 year old patient who started with walking and swallowing difficulty; followed by fever, abdominal and lower back pain. Mechanical breathing difficulties required a respiratory mechanic assistance. The diagnosis of Guillain-Barre syndrome was thought at first. Since the patient have had previous contact with a bat two months before the symptoms began, this suggested rabies as the main diagnosis, which was later confirmed by hair-bulb, cornea, oral mucosa and salival immunofluorescence. The brain and spinal cord MRI showed focal lesions in T2 and FLAIR sequences, compatible with encephalomyelitis. (author)

  18. MRI of intact plants

    OpenAIRE

    As, van, H.; Scheenen, T.; Vergeldt, F.J.

    2009-01-01

    Nuclear magnetic resonance imaging (MRI) is a non-destructive and non-invasive technique that can be used to acquire two- or even three-dimensional images of intact plants. The information within the images can be manipulated and used to study the dynamics of plant water relations and water transport in the stem, e.g., as a function of environmental (stress) conditions. Non-spatially resolved portable NMR is becoming available to study leaf water content and distribution of water in different...

  19. Magnetic rubber inspection (MRI)

    International Nuclear Information System (INIS)

    Magnetic Rubber Inspection (MRI) was developed to inspect for small cracks and flaws encountered in high performance aircraft. A formula of very fine magnetic particles immersed in a room temperature curing rubber is catalysed and poured into dams (retainers) on the surface of the part to be inspected. Inducing a magnetic field then causes the particles to be drawn to discontinuities in the component under test. These indicating particles are held to the discontinuity by magnetic attraction, as the rubber cures. The solid rubber cast (Replica) is then removed and examined under a microscope for indicating lines of particle concentrations. 3 refs., 6 figs

  20. Pharmacokinetics of Chiral Dendrimer-Triamine-Coordinated Gd-MRI Contrast Agents Evaluated by in Vivo MRI and Estimated by in Vitro QCM

    Directory of Open Access Journals (Sweden)

    Yuka Miyake

    2015-12-01

    Full Text Available Recently, we developed novel chiral dendrimer-triamine-coordinated Gd-MRI contrast agents (Gd-MRI CAs, which showed longitudinal relaxivity (r1 values about four times higher than that of clinically used Gd-DTPA (Magnevist®, Bayer. In our continuing study of pharmacokinetic differences derived from both the chirality and generation of Gd-MRI CAs, we found that the ability of chiral dendrimer Gd-MRI CAs to circulate within the body can be directly evaluated by in vitro MRI (7 T. In this study, the association constants (Ka of chiral dendrimer Gd-MRI CAs to bovine serum albumin (BSA, measured and calculated with a quartz crystal microbalance (QCM in vitro, were found to be an extremely easy means for evaluating the body-circulation ability of chiral dendrimer Gd-MRI CAs. The Ka values of S-isomeric dendrimer Gd-MRI CAs were generally greater than those of R-isomeric dendrimer Gd-MRI CAs, which is consistent with the results of our previous MRI study in vivo.

  1. Ovarian cysts on prenatal MRI

    Energy Technology Data Exchange (ETDEWEB)

    Nemec, Ursula [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Nemec, Stefan F., E-mail: stefan.nemec@meduniwien.ac.at [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Medical Genetics Institute, Cedars Sinai Medical Center, 8700 Beverly Boulevard, PACT Suite 400, Los Angeles, CA 90048 (United States); Bettelheim, Dieter [Department of Obstetrics and Gynaecology, Division of Prenatal Diagnosis and Therapy, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Brugger, Peter C. [Center of Anatomy and Cell Biology, Integrative Morphology Group, Medical University Vienna, Waehringerstrasse 13, A-1090 Vienna (Austria); Horcher, Ernst [Department of Pediatric Surgery, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Schoepf, Veronika [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Graham, John M.; Rimoin, David L. [Medical Genetics Institute, Cedars Sinai Medical Center, 8700 Beverly Boulevard, PACT Suite 400, Los Angeles, CA 90048 (United States); Weber, Michael; Prayer, Daniela [Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

    2012-08-15

    Objective: Ovarian cysts are the most frequently encountered intra-abdominal masses in females in utero. They may, at times, require perinatal intervention. Using magnetic resonance imaging (MRI) as an adjunct to ultrasonography (US) in prenatal diagnosis, we sought to demonstrate the ability to visualize ovarian cysts on prenatal MRI. Materials and methods: This retrospective study included 17 fetal MRI scans from 16 female fetuses (23-37 gestational weeks) with an MRI diagnosis of ovarian cysts after suspicious US findings. A multiplanar MRI protocol was applied to image and to characterize the cysts. The US and MRI findings were compared, and the prenatal findings were compared with postnatal imaging findings or histopathology. Results: Simple ovarian cysts were found in 10/16 cases and complex cysts in 7/16 cases, including one case with both. In 11/16 (69%) cases, US and MRI diagnoses were in agreement, and, in 5/16 (31%) cases, MRI specified or expanded the US diagnosis. In 6/16 cases, postnatal US showed that the cysts spontaneously resolved or decreased in size, and in 1/16 cases, postnatal imaging confirmed a hemorrhagic cyst. In 4/16 cases, the prenatal diagnoses were confirmed by surgery/histopathology, and for the rest, postnatal correlation was not available. Conclusion: Our results illustrate the MRI visualization of ovarian cysts in utero. In most cases, MRI will confirm the US diagnosis. In certain cases, MRI may provide further diagnostic information, additional to US, which is the standard technique for diagnosis, monitoring, and treatment planning.

  2. Ovarian cysts on prenatal MRI

    International Nuclear Information System (INIS)

    Objective: Ovarian cysts are the most frequently encountered intra-abdominal masses in females in utero. They may, at times, require perinatal intervention. Using magnetic resonance imaging (MRI) as an adjunct to ultrasonography (US) in prenatal diagnosis, we sought to demonstrate the ability to visualize ovarian cysts on prenatal MRI. Materials and methods: This retrospective study included 17 fetal MRI scans from 16 female fetuses (23–37 gestational weeks) with an MRI diagnosis of ovarian cysts after suspicious US findings. A multiplanar MRI protocol was applied to image and to characterize the cysts. The US and MRI findings were compared, and the prenatal findings were compared with postnatal imaging findings or histopathology. Results: Simple ovarian cysts were found in 10/16 cases and complex cysts in 7/16 cases, including one case with both. In 11/16 (69%) cases, US and MRI diagnoses were in agreement, and, in 5/16 (31%) cases, MRI specified or expanded the US diagnosis. In 6/16 cases, postnatal US showed that the cysts spontaneously resolved or decreased in size, and in 1/16 cases, postnatal imaging confirmed a hemorrhagic cyst. In 4/16 cases, the prenatal diagnoses were confirmed by surgery/histopathology, and for the rest, postnatal correlation was not available. Conclusion: Our results illustrate the MRI visualization of ovarian cysts in utero. In most cases, MRI will confirm the US diagnosis. In certain cases, MRI may provide further diagnostic information, additional to US, which is the standard technique for diagnosis, monitoring, and treatment planning.

  3. Measurement of the volume of internal capsule in healthy Chinese adults of the Han nationality on the high-resolution MRI

    International Nuclear Information System (INIS)

    Objective: To explore the normal range of the volume of internal capsules in Chinese adults of the Han nationality and its relationship with age, body habitus, and craniocerebral volume. Methods: One thousand healthy volunteers (age range =18 to 80 years) were divided into 5 groups according to their age; Group A (18 to 30 years old), group B (31 to 40 years), group C (41 to 50 years), group D (51 to 60 years), and group E (61 to 80 years). Each group consisted of 100 males and 100 females. MR imaging was performed in all of the volunteers using T1 weighted three-dimensional magnetization prepared rapid acquisition gradient echo sequence. After three dimension data reconstruction, the volumes of bilateral internal capsules were manually measured. The volumes of bilateral internal capsules were compared by paired sample t test. The internal capsule volumes were compared between male and female by independent sample t test, and the differences among 5 age groups were compared by one-way ANOVA. The relationship between the volumes of internal capsule and age, body habitus or cerebral volume were analyzed using bivariate correlation. Results: The left and right internal capsule volumes were (2809 ± 393) and (2677 ± 343 ) mm3 respectively. The left internal capsule volumes were significantly larger than that of right (t=12.078, P<0.05). The left and right side of internal capsule volumes in male were (2863 ± 396) and (2744 ±358) mm3 respectively, and (2754 ±385) and (2609 ±314) mm3 in female. The left and right internal capsule volumes were larger in males than in female (t=1.982, 2.851; P<0.05). The left internal capsule volume of the 5 age groups were (3273 ± 361), (2943 ± 299), (2777 ± 255), (2607 ± 199), (2444 ±213) mm3, and the right were (2993 ± 361), (2814 ± 270), (2682 ± 239), (2543 ± 219), (2351 ±210) mm3. There were significant differences among 5 age groups between left and right internal capsule volume (F=55.244, 34.493; P<0.05). There was

  4. Coccygeal movement: Assessment with dynamic MRI

    Energy Technology Data Exchange (ETDEWEB)

    Grassi, Roberto [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy)]. E-mail: Roberto.grassi@unina2.it; Lombardi, Giulio [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy); Reginelli, Alfonso [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy); Capasso, Francesco [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy); Romano, Francesco [Institute of Radiology, Second University of Naples, Piazza Miraglia, 80138 Naples (Italy); Floriani, Irene [Clinical Trial Unit, Oncology Department, Istituto di Ricerche Farmacologiche ' Mario Negri' , Milan (Italy); Colacurci, Nicola [Department of Gynecologic Obstetric and Reproduction Sciences, Second University of Naples, 80138 Naples (Italy)

    2007-03-15

    Purpose: Chronic coccygodynia is a difficult problem diagnostically and therapeutically. Moreover, there is no deep knowledge especially in the field of imaging of chronic coccygodynia. In this study several possible measurements are proposed, which all are able to demonstrate coccygeal movement during defecation, in order to assess coccygeal mobility using dynamic MRI during maximum contraction and during straining-evacuation. Materials and methods: A dynamic MRI study of the pelvic floor was performed in 112 patients. Five methods of measurement were assessed. Coccygeal movements were determined through the evaluation of three angles pair and two different distances measured during the phase of maximum contraction and during the phase of straining-evacuation. Results were compared according to age, sex, parity and experience of minor trauma. No patient included in the study had coccygodynia. Measurements taken by two radiologist were compared to determine interobserver agreement. Results: The maximum measurement values of the two distances are homogeneous, between 9 and 9.4 mm. The maximum measurement values of the three angles showed a difference that is between 21 deg. and 38 deg. Two of three angles showed a major measurement values in the funtional texts. In only one patient the coccyx was not mobile. Conclusion: Our dynamic MRI study indicates that the coccyx is mobile during defecation and that it is possible to demonstrate coccygeal excursions by assessing the difference between its positions at maximum contraction and during straining-evacuation. The measurement methods used in this study for evaluating coccygeal movements resulted in variably sized observed differences, but all yielded statistically significant results in demonstrating coccygeal excursion. Among the five measurement methods, two resulted in the largest differences. Our data indicate no correlation between coccygeal movements and age, sex, parity, minor trauma and coccygodynia.

  5. Coccygeal movement: Assessment with dynamic MRI

    International Nuclear Information System (INIS)

    Purpose: Chronic coccygodynia is a difficult problem diagnostically and therapeutically. Moreover, there is no deep knowledge especially in the field of imaging of chronic coccygodynia. In this study several possible measurements are proposed, which all are able to demonstrate coccygeal movement during defecation, in order to assess coccygeal mobility using dynamic MRI during maximum contraction and during straining-evacuation. Materials and methods: A dynamic MRI study of the pelvic floor was performed in 112 patients. Five methods of measurement were assessed. Coccygeal movements were determined through the evaluation of three angles pair and two different distances measured during the phase of maximum contraction and during the phase of straining-evacuation. Results were compared according to age, sex, parity and experience of minor trauma. No patient included in the study had coccygodynia. Measurements taken by two radiologist were compared to determine interobserver agreement. Results: The maximum measurement values of the two distances are homogeneous, between 9 and 9.4 mm. The maximum measurement values of the three angles showed a difference that is between 21 deg. and 38 deg. Two of three angles showed a major measurement values in the funtional texts. In only one patient the coccyx was not mobile. Conclusion: Our dynamic MRI study indicates that the coccyx is mobile during defecation and that it is possible to demonstrate coccygeal excursions by assessing the difference between its positions at maximum contraction and during straining-evacuation. The measurement methods used in this study for evaluating coccygeal movements resulted in variably sized observed differences, but all yielded statistically significant results in demonstrating coccygeal excursion. Among the five measurement methods, two resulted in the largest differences. Our data indicate no correlation between coccygeal movements and age, sex, parity, minor trauma and coccygodynia

  6. Combination of signal intensity measurements of lesions in the peripheral zone of prostate with MRI and serum PSA level for differentiating benign disease from prostate cancer

    International Nuclear Information System (INIS)

    The aim of this study was to predict the benign or malignant nature of a prostatic lesion by defining a threshold value of signal intensity ratio and a limiting value of serum prostate-specific antigen (PSA) in patients with elevated PSA level. Twenty-six patients with elevated PSA level and no hypoechogenic lesions at endosonography underwent MR imaging using an endorectal body phased-array coil at 1.5 T (Siemens Magnetom Symphony). A T2-weighted turbo-spin-echo (TSE) pulse sequence was applied in a transverse orientation. Two radiologists evaluated the images. In the presence of a pathological finding they defined regions of interest (ROI) in the suspicious pathological area of the peripheral zone and in muscle for reference. The quotient of the two ROIs was calculated and then correlated with the actual PSA level. Diagnosis was confirmed by prostate biopsy. Ten of 12 patients with quotients smaller than 4 showed cancer at histology. Nine of 12 men with cancer proven by biopsy had PSA levels higher than 10 ng/ml. A significant difference (p < 0.001) was found between the quotients of cancer and quotients of chronic prostatitis, fibrosis, or glandular atrophy. The accuracy of tumor differentiation of the method was 77 %. Measurement of signal intensity quotients in the peripheral zone of the prostate in combination with knowledge of defined limits of PSA levels the technique could be helpful in detecting additional cancer areas for prostate biopsy. False-negative tumor results of standard sextant biopsy can be reduced. In men with high PSA values the method has a role in differentiating between patients who require prostate biopsy and those of clinical observation. (orig.)

  7. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... bear denotes child-specific content. Related Articles and Media MR Angiography (MRA) Magnetic Resonance, Functional (fMRI) - Brain Head and Neck Cancer Treatment Brain Tumor Treatment Magnetic Resonance Imaging (MRI) Safety Alzheimer's Disease Head Injury Brain Tumors Images related to Magnetic ...

  8. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses a ...

  9. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    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 ...

  10. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    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 ...

  11. Postmortem MRI of bladder agenesis

    Energy Technology Data Exchange (ETDEWEB)

    Barber, Brendan R. [St George' s Hospital, Radiology Department, London (United Kingdom); Weber, Martin A. [Great Ormond Street Hospital for Children, Department of Histopathology, London (United Kingdom); Bockenhauer, Detlef [Great Ormond Street Hospital for Children, Department of Nephrology, London (United Kingdom); Hiorns, Melanie P.; McHugh, Kieran [Great Ormond Street Hospital for Children, Radiology Department, London (United Kingdom)

    2011-01-15

    We report a 35-week preterm neonate with bladder agenesis and bilateral dysplastic kidneys. A suprapubic catheter was inadvertently inserted into one of the larger inferior cysts of the left dysplastic kidney. A postmortem MRI scan was performed with the findings being confirmed on autopsy. We are unaware of another postmortem MRI study demonstrating bladder agenesis. (orig.)

  12. MRI Findings In Dengue Encephalitis

    Directory of Open Access Journals (Sweden)

    Ashraf V.V

    2004-01-01

    Full Text Available Neurological manifestations are rare in dengue fever. Two cases with encephalopathy and systemic features of dengue fever with abnormal CSF and MR imaging are reported. Striking MRI finding was bilateral symmetrical thalamic lesions similar to those reported in Japanese encephalitis. This report highlights that MRI findings can be similar in dengue and Japanese encephalitis.

  13. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... 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, including tumors. MRI enables the discovery of ...