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Sample records for resonance imaging evaluation

  1. Magnetic Resonance Imaging Evaluation of Cardiac Masses

    PubMed Central

    Braggion-Santos, Maria Fernanda; Koenigkam-Santos, Marcel; Teixeira, Sara Reis; Volpe, Gustavo Jardim; Trad, Henrique Simão; Schmidt, André

    2013-01-01

    Background Cardiac tumors are extremely rare; however, when there is clinical suspicion, proper diagnostic evaluation is necessary to plan the most appropriate treatment. In this context, cardiovascular magnetic resonance imaging (CMRI) plays an important role, allowing a comprehensive characterization of such lesions. Objective To review cases referred to a CMRI Department for investigation of cardiac and paracardiac masses. To describe the positive case series with a brief review of the literature for each type of lesion and the role of cardiovascular magnetic resonance imaging in evaluation. Methods Between August 2008 and December 2011, all cases referred for CMRI with suspicion of tumor involving the heart were reviewed. Cases with positive histopathological diagnosis, clinical evolution or therapeutic response compatible with the clinical suspicion and imaging findings were selected. Results Among the 13 cases included in our study, eight (62%) had histopathological confirmation. We describe five benign tumors (myxomas, rhabdomyoma and fibromas), five malignancies (sarcoma, lymphoma, Richter syndrome involving the heart and metastatic disease) and three non-neoplastic lesions (pericardial cyst, intracardiac thrombus and infectious vegetation). Conclusion CMRI plays an important role in the evaluation of cardiac masses of non-neoplastic and neoplastic origin, contributing to a more accurate diagnosis in a noninvasive manner and assisting in treatment planning, allowing safe clinical follow-up with good reproducibility. PMID:23887734

  2. Magnetic resonance imaging in the evaluation of acute stroke.

    PubMed

    Olivot, Jean Marc; Marks, Michael P

    2008-10-01

    The ability to use physiologic imaging with either magnetic resonance (MR) or computed tomography to help define irreversibly injured brain (the infarct core) and tissue at risk of infarct (reversible ischemic penumbra) holds great promise in the future treatment of stroke. The physiologic principles and concepts underlying the evaluation for mismatch between injured tissue and tissue at risk are similar for the 2 imaging techniques. Multimodal MR imaging (diffusion-weighted imaging/perfusion-weighted imaging/MR angiography) provides a validated penumbral selection criteria based on the results of 2 clinical trials (diffusion and perfusion imaging evaluation for understanding stroke evolution and echoplanar imaging thrombolysis evaluation). Computed tomographic perfusion parameters have also been calculated to optimize final infarct prediction. Both techniques await further study to prove their capability of selecting cases for short-term recanalization/reperfusion therapy.

  3. Elbow magnetic resonance imaging: imaging anatomy and evaluation.

    PubMed

    Hauptfleisch, Jennifer; English, Collette; Murphy, Darra

    2015-04-01

    The elbow is a complex joint. Magnetic resonance imaging (MRI) is often the imaging modality of choice in the workup of elbow pain, especially in sports injuries and younger patients who often have either a history of a chronic repetitive strain such as the throwing athlete or a distinct traumatic injury. Traumatic injuries and alternative musculoskeletal pathologies can affect the ligaments, musculotendinous, cartilaginous, and osseous structures of the elbow as well as the 3 main nerves to the upper limb, and these structures are best assessed with MRI.Knowledge of the complex anatomy of the elbow joint as well as patterns of injury and disease is important for the radiologist to make an accurate diagnosis in the setting of elbow pain. This chapter will outline elbow anatomy, basic imaging parameters, compartmental pathology, and finally applications of some novel MRI techniques.

  4. Magnetic resonance imaging in the evaluation of congestive cardiac failure.

    PubMed

    Rajiah, Prabhakar

    2012-07-01

    Congestive cardiac failure is the end-result of various cardiac disorders, and is a major contributor to morbidity, mortality, and financial burden throughout the world. Due to advances in the knowledge of the disease and scanner technology, magnetic resonance imaging (MRI) is playing an increasingly important role in the evaluation of cardiac failure, including in establishing diagnosis, problem solving, risk stratification, and monitoring of therapy. This review discusses and illustrates the role of MRI in the assessment of congestive cardiac failure.

  5. Computed tomography and magnetic resonance imaging evaluation of pericardial disease

    PubMed Central

    Shahid, Muhammad; Watkin, Richard W.

    2016-01-01

    Pericardial diseases are commonly encountered in clinical practice and may present as an isolated process or in association with various systemic conditions. Traditionally transthoracic echocardiography (TTE) has been the method of choice for the evaluation of suspected pericardial disease but increasingly computed tomography (CT) and magnetic resonance imaging (MRI) are also being used as part of a rational multi-modality imaging approach tailored to the specific clinical scenario. This paper reviews the role of CT and MRI across the spectrum of pericardial diseases. PMID:27429911

  6. Evaluation of muscle injury using magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    LeBlanc, A. D.; Jaweed, M.; Evans, H.

    1993-01-01

    The objective of this study was to investigate spin echo T2 relaxation time changes in thigh muscles after intense eccentric exercise in healthy men. Spin echo and calculated T2 relaxation time images of the thighs were obtained on several occasions after exercise of one limb; the contralateral limb served as control. Muscle damage was verified by elevated levels of serum creatine kinase (CK). Thirty percent of the time no exercise effect was discernible on the magnetic resonance (MR) images. In all positive MR images (70%) the semitendinosus muscle was positive, while the biceps femoris, short head, and gracilis muscles were also positive in 50% and 25% of the total cases, respectively. The peak T2 relaxation time and serum CK were correlated (r = 0.94, p<0.01); temporal changes in muscle T2 relaxation time and serum CK were similar, although T2 relaxation time remained positive after serum CK returned to background levels. We conclude that magnetic resonance imaging can serve as a useful tool in the evaluation of eccentric exercise muscle damage by providing a quantitative indicator of damage and its resolution as well as the specific areas and muscles.

  7. Evaluation of muscle injury using magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    LeBlanc, A. D.; Jaweed, M.; Evans, H.

    1993-01-01

    The objective of this study was to investigate spin echo T2 relaxation time changes in thigh muscles after intense eccentric exercise in healthy men. Spin echo and calculated T2 relaxation time images of the thighs were obtained on several occasions after exercise of one limb; the contralateral limb served as control. Muscle damage was verified by elevated levels of serum creatine kinase (CK). Thirty percent of the time no exercise effect was discernible on the magnetic resonance (MR) images. In all positive MR images (70%) the semitendinosus muscle was positive, while the biceps femoris, short head, and gracilis muscles were also positive in 50% and 25% of the total cases, respectively. The peak T2 relaxation time and serum CK were correlated (r = 0.94, p<0.01); temporal changes in muscle T2 relaxation time and serum CK were similar, although T2 relaxation time remained positive after serum CK returned to background levels. We conclude that magnetic resonance imaging can serve as a useful tool in the evaluation of eccentric exercise muscle damage by providing a quantitative indicator of damage and its resolution as well as the specific areas and muscles.

  8. [Fetal magnetic resonance imaging evaluation of congenital diaphragmatic hernia].

    PubMed

    Sebastià, C; Garcia, R; Gomez, O; Paño, B; Nicolau, C

    2014-01-01

    A diaphragmatic hernia is defined as the protrusion of abdominal viscera into the thoracic cavity through a normal or pathological orifice. The herniated viscera compress the lungs, resulting in pulmonary hypoplasia and secondary pulmonary hypertension, which are the leading causes of neonatal death in patients with congenital diaphragmatic hernia. Congenital diaphragmatic hernia is diagnosed by sonography in routine prenatal screening. Although magnetic resonance imaging is fundamentally used to determine whether the liver is located within the abdomen or has herniated into the thorax, it also can provide useful information about other herniated structures and the degree of pulmonary hypoplasia. The aim of this article is to review the fetal magnetic resonance findings for congenital diaphragmatic hernia and the signs that enable us to establish the neonatal prognosis when evaluating pulmonary hypoplasia.

  9. Thoracic magnetic resonance imaging for the evaluation of pulmonary emphysema.

    PubMed

    Lee, Sang Min; Seo, Joon Beom; Hwang, Hye Jeon; Kim, Eun Young; Oh, Sang Young; Kim, Ji-Eun

    2013-05-01

    Pulmonary emphysema is a pathologic condition characterized by permanently enlarged airspaces distal to the terminal bronchiole with destruction of the alveolar walls. Functional information of the lungs is important to understand the pathophysiology of emphysema and that of chronic obstructive pulmonary disease. With the recent developments in magnetic resonance imaging (MRI) techniques, functional MRI with variable MR sequences can be used for the evaluation of different physiological and anatomic changes seen in cases of pulmonary emphysema. In this review article, we will focus on a brief description of each method, results of some of the most recent work, and the clinical application of such knowledge.

  10. Beef assessments using functional magnetic resonance imaging and sensory evaluation.

    PubMed

    Tapp, W N; Davis, T H; Paniukov, D; Brooks, J C; Brashears, M M; Miller, M F

    2017-04-01

    Functional magnetic resonance imaging (fMRI) has been used to unveil how some foods and basic rewards are processed in the human brain. This study evaluated how resting state functional connectivity in regions of the human brain changed after differing qualities of beef steaks were consumed. Functional images of participants (n=8) were collected after eating high or low quality beef steaks on separate days, after consumption a sensory ballot was administered to evaluate consumers' perceptions of tenderness, juiciness, flavor, and overall liking. Imaging data showed that high quality steak samples resulted in greater functional connectivity to the striatum, medial orbitofrontal cortex, and insular cortex at various stages after consumption (P≤0.05). Furthermore, high quality steaks elicited higher sensory ballot scores for each palatability trait (P≤0.01). Together, these results suggest that resting state fMRI may be a useful tool for evaluating the neural process that follows positive sensory experiences such as the enjoyment of high quality beef steaks. Published by Elsevier Ltd.

  11. Magnetic resonance imaging in evaluation of the common bile duct.

    PubMed

    Musella, M; Barbalace, G; Capparelli, G; Carrano, A; Castaldo, P; Tamburrini, O; Musella, S

    1998-01-01

    The ideal method for evaluation of the common bile duct (CBD) before or during cholecystectomy remains controversial. Magnetic resonance cholangiography (MRC) is a new, promising technique. A prospective evaluation is reported. Sixty-one patients (45 women) were studied by MRC. There were 29 patients with symptomatic gallstone disease and without clinical, biochemical or ultrasonographic evidence of CBD stones (group 1); 28 of them also underwent intraoperative cholangiography (IOC). In addition, there were 21 patients with symptomatic gallstone disease, with mild biochemical and ultrasonographic signs of CBD involvement (group 2), of whom 19 underwent IOC, and 11 patients with symptomatic CBD stones (group 3), nine of whom had preoperative endoscopic retrograde cholangiopancreatography (ERCP) following MRC. MRC showed that no patient in group 1 and three patients in group 2 had CBD stones. Three patients (one in group 1, two in group 2) did not undergo IOC because of technical or clinical problems. In group 3, ERCP confirmed the results of MRC in nine patients. Two patients underwent open surgery because of ultrasonographic, MRC and radiographic signs of pancreatic malignancy. MRC could replace IOC and ERCP for identification of asymptomatic CBD stones. In symptomatic patients MRC combined with other non-invasive imaging techniques can direct the surgeon to appropriate management.

  12. Fetal cystic lung lesions: evaluation with magnetic resonance imaging.

    PubMed

    Liu, Yu-Peng; Chen, Chih-Ping; Shih, Shin-Lin; Chen, Yi-Fang; Yang, Fei-Shih; Chen, Su-Chiu

    2010-06-01

    To investigate the contribution of magnetic resonance imaging (MRI) to the diagnosis of fetal cystic lung lesions found on routine prenatal ultrasound (US). Experienced radiologists retrospectively reviewed 34 fetal MRI studies performed in 20 fetuses (from 20 to 35 gestational weeks; including 14 repeat studies 10 weeks after the initial MRI), focusing on shape, signal characteristics, feeding artery, volume change, and location of the cystic lesions. Diagnoses were confirmed after birth by postnatal multidetector computed tomography (MDCT) and/or surgery. Bronchopulmonary sequestration (BPS) in the second trimester appeared as a well-defined, homogeneous, hyperintense mass (pure BPS) in eight cases or as a lobulated, inhomogeneous hyperintense mass (BPS mixed with congenital cystic adenomatoid malformation (CCAM)) in three cases. The feeding artery was visible in all 11 cases in the initial MRI, and regression of the mass was seen in 7 cases. As the mass regressed in the third trimester, the signal intensity decreased, becoming inhomogeneous, and the margins became lobulated. The mean initial ratio of the volume of the BPS lesion to the ipsilateral lung in lesions with partial regression was 82%; the mean initial ratio in lesions with nearly complete regression was 61%. CCAM (6) cases also appeared as a hyperintense lobulated mass, and as the lesions regressed, they decreased in size and signal intensity. As with BPS, the larger the lesion on initial MRI, the less likely it was to regress completely. Congenital lobar fluid overload in three cases appeared as a hyperintense, homogeneous lobe with stretched hilar vessels. Prenatal MRI is useful as a diagnostic tool complementary to US for evaluating fetal cystic lung lesions. Smaller lung lesions (<60%) may regress completely.

  13. Development and validation of a questionnaire evaluating patient anxiety during Magnetic Resonance Imaging: the Magnetic Resonance Imaging-Anxiety Questionnaire (MRI-AQ).

    PubMed

    Ahlander, Britt-Marie; Årestedt, Kristofer; Engvall, Jan; Maret, Eva; Ericsson, Elisabeth

    2016-06-01

    To develop and validate a new instrument measuring patient anxiety during Magnetic Resonance Imaging examinations, Magnetic Resonance Imaging- Anxiety Questionnaire. Questionnaires measuring patients' anxiety during Magnetic Resonance Imaging examinations have been the same as used in a wide range of conditions. To learn about patients' experience during examination and to evaluate interventions, a specific questionnaire measuring patient anxiety during Magnetic Resonance Imaging is needed. Psychometric cross-sectional study with test-retest design. A new questionnaire, Magnetic Resonance Imaging-Anxiety Questionnaire, was designed from patient expressions of anxiety in Magnetic Resonance Imaging-scanners. The sample was recruited between October 2012-October 2014. Factor structure was evaluated with exploratory factor analysis and internal consistency with Cronbach's alpha. Criterion-related validity, known-group validity and test-retest was calculated. Patients referred for Magnetic Resonance Imaging of either the spine or the heart, were invited to participate. The development and validation of Magnetic Resonance Imaging-Anxiety Questionnaire resulted in 15 items consisting of two factors. Cronbach's alpha was found to be high. Magnetic Resonance Imaging-Anxiety Questionnaire correlated higher with instruments measuring anxiety than with depression scales. Known-group validity demonstrated a higher level of anxiety for patients undergoing Magnetic Resonance Imaging scan of the heart than for those examining the spine. Test-retest reliability demonstrated acceptable level for the scale. Magnetic Resonance Imaging-Anxiety Questionnaire bridges a gap among existing questionnaires, making it a simple and useful tool for measuring patient anxiety during Magnetic Resonance Imaging examinations. © 2016 The Authors. Journal of Advanced Nursing Published by John Wiley & Sons Ltd.

  14. Application of Advanced Magnetic Resonance Imaging Techniques in Evaluation of the Lower Extremity

    PubMed Central

    Braun, Hillary J.; Dragoo, Jason L.; Hargreaves, Brian A.; Levenston, Marc E.; Gold, Garry E.

    2012-01-01

    Synopsis This article reviews current magnetic resonance imaging techniques for imaging the lower extremity, focusing on imaging of the knee, ankle, and hip joints. Recent advancements in MRI include imaging at 7 Tesla, using multiple receiver channels, T2* imaging, and metal suppression techniques, allowing more detailed visualization of complex anatomy, evaluation of morphological changes within articular cartilage, and imaging around orthopedic hardware. PMID:23622097

  15. MRI (Magnetic Resonance Imaging)

    MedlinePlus

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

  16. Cardiac magnetic resonance imaging has limited additional yield in cryptogenic stroke evaluation after transesophageal echocardiography.

    PubMed

    Liberman, Ava L; Kalani, Rizwan E; Aw-Zoretic, Jessie; Sondag, Matthew; Daruwalla, Vistasp J; Mitter, Sumeet S; Bernstein, Richard; Collins, Jeremy D; Prabhakaran, Shyam

    2017-01-01

    Background The use of cardiac magnetic resonance imaging is increasing, but its role in the diagnostic work-up following ischemic stroke has received limited study. We aimed to explore the added yield of cardiac magnetic resonance imaging to identify cardio-aortic sources not detected by transesophageal echocardiography among patients with cryptogenic stroke. Methods A retrospective single-center cohort study was performed from 01 January 2009 to 01 March 2013. Consecutive patients who had both a stroke protocol cardiac magnetic resonance imaging and a transesophageal echocardiography preformed during a single hospitalization were included. All cardiac magnetic resonance imaging studies underwent independent, blinded review by two investigators. We applied the causative classification system for ischemic stroke to all patients, first blinded to cardiac magnetic resonance imaging results; we then reapplied the causative classification system using cardiac magnetic resonance imaging. Standard statistical tests to evaluate stroke subtype reclassification rates were used. Results Ninety-three patients were included in the final analysis; 68.8% were classified as cryptogenic stroke after initial diagnostic evaluation. Among patients with cryptogenic stroke, five (7.8%) were reclassified due to cardiac magnetic resonance imaging findings: one was reclassified as "cardio-aortic embolism evident" due to the presence of a patent foramen ovale and focal cardiac infarct and four were reclassified as "cardio-aortic embolism possible" due to mitral valve thickening (n = 1) or hypertensive cardiomyopathy (n = 3). Overall, findings on cardiac magnetic resonance imaging reduced the percentage of patients with cryptogenic stroke by slightly more than 1%. Conclusion Our stroke subtype reclassification rate after the addition of cardiac magnetic resonance imaging results to a diagnostic work-up which includes transesophageal echocardiography was very low. Prospective studies

  17. Evaluation of the lateral pterygoid muscle using magnetic resonance imaging

    PubMed Central

    D'Ippolito, SM; Borri Wolosker, AM; D'Ippolito, G; Herbert de Souza, B; Fenyo-Pereira, M

    2010-01-01

    Objectives The aims of this study were to evaluate the visibility of the lateral pterygoid muscle (LPM) in temporomandibular joint (TMJ) images obtained by MRI, using different projections and to compare image findings with clinical symptoms of patients with and without temporomandibular disorders (TMD). Methods In this study, LPM images of 50 participants with and without TMDs were investigated by MRI. The images of the LPM in different projections of 100 TMJs from 35 participants (70 TMJs) with and 15 participants (30 TMJs) without clinical signs and symptoms of TMD were visible and analysed. Results The oblique sagittal and axial images of the TMJ clearly showed the LPM. Hypertrophy (1.45%), atrophy (2.85%) and contracture (2.85%) were the abnormalities found in the LPM. TMD signs, such as hypermobility (11.4%), hypomobility (12.9%) and disc displacement (20.0%), could be seen in TMJ images. Related clinical symptoms, such as pain (71.4%), articular sounds (30.4%), bruxism (25.7%) and headache (22.9%), were observed. Conclusions Patients with TMD can present with alterations in the LPM thickness. Patients without TMD also showed alterations, such as atrophy and contracture, in TMJ images. Recognition of alterations in the LPM will improve our understanding of clinical symptoms and pathophysiology of TMD, and may lead to a more specific diagnosis of these disorders. PMID:21062943

  18. Noninvasive amide proton transfer magnetic resonance imaging in evaluating the grading and cellularity of gliomas.

    PubMed

    Bai, Yan; Lin, Yusong; Zhang, Wei; Kong, Lingfei; Wang, Lifu; Zuo, Panli; Vallines, Ignacio; Schmitt, Benjamin; Tian, Jie; Song, Xiaolei; Zhou, Jinyuan; Wang, Meiyun

    2017-01-24

    Using noninvasive magnetic resonance imaging techniques to accurately evaluate the grading and cellularity of gliomas is beneficial for improving the patient outcomes. Amide proton transfer imaging is a noninvasive molecular magnetic resonance imaging technique based on chemical exchange saturation transfer mechanism that detects endogenous mobile proteins and peptides in biological tissues. Between August 2012 and November 2015, a total number of 44 patients with pathologically proven gliomas were included in this study. We compared the capability of amide proton transfer magnetic resonance imaging with that of noninvasive diffusion-weighted imaging and noninvasive 3-dimensional pseudo-continuous arterial spin imaging in evaluating the grading and cellularity of gliomas. Our results reveal that amide proton transfer magnetic resonance imaging is a superior imaging technique to diffusion-weighted imaging and 3-dimensional pseudo-continuous arterial spin imaging in the grading of gliomas. In addition, our results showed that the Ki-67 index correlated better with the amide proton transfer-weighted signal intensity than with the apparent diffusion coefficient value or the cerebral blood flow value in the gliomas. Amide proton transfer magnetic resonance imaging is a promising method for predicting the grading and cellularity of gliomas.

  19. Noninvasive amide proton transfer magnetic resonance imaging in evaluating the grading and cellularity of gliomas

    PubMed Central

    Zhang, Wei; Kong, Lingfei; Wang, Lifu; Zuo, Panli; Vallines, Ignacio; Schmitt, Benjamin; Tian, Jie; Song, Xiaolei; Zhou, Jinyuan; Wang, Meiyun

    2017-01-01

    Using noninvasive magnetic resonance imaging techniques to accurately evaluate the grading and cellularity of gliomas is beneficial for improving the patient outcomes. Amide proton transfer imaging is a noninvasive molecular magnetic resonance imaging technique based on chemical exchange saturation transfer mechanism that detects endogenous mobile proteins and peptides in biological tissues. Between August 2012 and November 2015, a total number of 44 patients with pathologically proven gliomas were included in this study. We compared the capability of amide proton transfer magnetic resonance imaging with that of noninvasive diffusion-weighted imaging and noninvasive 3-dimensional pseudo-continuous arterial spin imaging in evaluating the grading and cellularity of gliomas. Our results reveal that amide proton transfer magnetic resonance imaging is a superior imaging technique to diffusion-weighted imaging and 3-dimensional pseudo-continuous arterial spin imaging in the grading of gliomas. In addition, our results showed that the Ki-67 index correlated better with the amide proton transfer-weighted signal intensity than with the apparent diffusion coefficient value or the cerebral blood flow value in the gliomas. Amide proton transfer magnetic resonance imaging is a promising method for predicting the grading and cellularity of gliomas. PMID:27992380

  20. Evaluation of sub-microsecond recovery resonators for In Vivo Electron Paramagnetic Resonance Imaging

    PubMed Central

    F, Hyodo; S, Subramanian; N, Devasahayam; R, Murugesan; K, Matsumoto; JB, Mitchell; MC, Krishna

    2008-01-01

    Time-domain (TD) electron paramagnetic resonance (EPR) imaging at 300 MHz for in vivo applications requires resonators with recovery times less than 1 microsecond after pulsed excitation to reliably capture the rapidly decaying free induction decay (FID). In this study, we tested the suitability of the Litz foil coil resonator (LCR), commonly used in MRI, for in vivo EPR/EPRI applications in the TD mode and compared with parallel coil resonator (PCR). In TD mode, the sensitivity of LCR was lower than that of the PCR. However, in continuous wave (CW) mode, the LCR showed better sensitivity. The RF homogeneity was similar in both the resonators. The axis of the RF magnetic field is transverse to the cylindrical axis of the LCR, making the resonator and the magnet co-axial. Therefore, the loading of animals, and placing of the anesthesia nose cone and temperature monitors was more convenient in the LCR compared to the PCR whose axis is perpendicular to the magnet axis. PMID:18042414

  1. Using 3 Tesla magnetic resonance imaging in the pre-operative evaluation of tongue carcinoma.

    PubMed

    Moreno, K F; Cornelius, R S; Lucas, F V; Meinzen-Derr, J; Patil, Y J

    2017-09-01

    This study aimed to evaluate the role of 3 Tesla magnetic resonance imaging in predicting tongue tumour thickness via direct and reconstructed measures, and their correlations with corresponding histological measures, nodal metastasis and extracapsular spread. A prospective study was conducted of 25 patients with histologically proven squamous cell carcinoma of the tongue and pre-operative 3 Tesla magnetic resonance imaging from 2009 to 2012. Correlations between 3 Tesla magnetic resonance imaging and histological measures of tongue tumour thickness were assessed using the Pearson correlation coefficient: r values were 0.84 (p < 0.0001) and 0.81 (p < 0.0001) for direct and reconstructed measurements, respectively. For magnetic resonance imaging, direct measures of tumour thickness (mean ± standard deviation, 18.2 ± 7.3 mm) did not significantly differ from the reconstructed measures (mean ± standard deviation, 17.9 ± 7.2 mm; r = 0.879). Moreover, 3 Tesla magnetic resonance imaging had 83 per cent sensitivity, 82 per cent specificity, 82 per cent accuracy and a 90 per cent negative predictive value for detecting cervical lymph node metastasis. In this cohort, 3 Tesla magnetic resonance imaging measures of tumour thickness correlated highly with the corresponding histological measures. Further, 3 Tesla magnetic resonance imaging was an effective method of detecting malignant adenopathy with extracapsular spread.

  2. Comparison of magnetic resonance imaging and radionuclide imaging in the evaluation of renal transplant failure

    SciTech Connect

    Goldsmith, M.S.; Tanasescu, D.E.; Waxman, A.D.; Crues, J.V. III

    1988-04-01

    Magnetic resonance imaging (MRI) was compared with radionuclide scintigraphy (RNS) in 16 patients with renal transplants undergoing renal failure to determine which modality could best discriminate between rejection, acute tubular necrosis (ATN), and cyclosporin nephrotoxicity (CN). Although all rejecting transplants had reduced corticomedullary differentiation (CMD) on T1-weighted MR images, four of five cases of ATN had appearances that could not be distinguished from rejection. A normal CMD suggests nonrejection, but diminished CMD is nonspecific. Tc-99m DTPA/I-131 hippuran RNS was superior to MRI in differentiating rejection from ATN. Although ATN and CN have similar RNS patterns, this distinction can usually be made based on the clinical time course. Other potential uses of MRI in the evaluation of the renal transplants are discussed.

  3. Ultrasonography and magnetic resonance imaging evaluation of pediatric spinal anomalies

    PubMed Central

    Dhingani, Dhaval Durlabhbhai; Boruah, Deb Kumar; Dutta, Hemonta Kumar; Gogoi, Rudra Kanta

    2016-01-01

    Context: Spinal dysraphisms are congenital abnormalities of the spine due to imperfect fusion of midline mesenchymal, bony and neural structures. Imaging plays a vital role in their evaluation as significant portion of patients may present with concurrent anomalies that need to be corrected simultaneously to avoid repeat surgeries. Aims: The aims of the study were to evaluate Spinal dysraphisms using USG and MRI and to correlate imaging findings with operative findings in patients undergoing surgery. Settings and Design: Hospital based observational study conducted over a period of year. Materials and Methods: 38 cases of both sexes and below 12 years of age with spinal dysraphism were studied. USG was performed in 29 cases where acoustic window was available for proper evaluation. MRI was performed in all cases. USG findings were compared with MRI findings and operative follow up was taken in 23 cases who underwent operative management. Statistical Analysis Used: Results were analysed using percentage and arithmetic mean. Results: 39.47 % cases were male and 60.53 % cases were female. Neonatal period was the most common presenting age group. Closed spinal dysraphism (63.16%) was more common than open (36.84%). 79.31% cases showed full agreement between spinal USG and MRI examinations and 6 out of 20.69% showed partial agreement. On operative correlation, USG findings were confirmatory in 91.30% cases and MRI findings were confirmatory in 100% cases. Conclusions: USG can be used as the initial modality for evaluation of spinal dysraphism as well as for screening of suspected cases. MRI is indicated to confirm abnormal USG findings, which shows all concurrent abnormalities and also provides additional anatomical details relevant to surgical planning. PMID:27857788

  4. Horizontal Long Axis Imaging Plane for Evaluation of Right Ventricular Function on Cardiac Magnetic Resonance Imaging

    PubMed Central

    Chaturvedi, Abhishek; Whitnah, Joseph; Maki, Jeffrey H; Baran, Timothy; Mitsumori, Lee M

    2016-01-01

    Purpose: The purpose of this study was to evaluate a horizontal long axis (HLA) magnetic resonance imaging (MRI) plane aligned to the long axis of the right ventricular (RV) cavity for functional analysis by comparing the measurement variability and time required for the analysis with that using a short-axis (SAX) image orientation. Materials and Methods: Thirty-four cardiac MRI exams with cine balanced steady-state free precession image stacks in both the SAX and the HLA of the RV (RHLA) were evaluated. Two reviewers independently traced RV endocardial borders on each image of the cine stacks. The time required to complete each set of traces was recorded, and the RV end-diastolic volume, end-systolic volume, and ejection fraction were calculated. Analysis times and RV measurements were compared between the two orientations. Results: Analysis time for each reviewer was significantly shorter for the RHLA stack (reviewer 1 = 6.4 ± 1.8 min, reviewer 2 = 6.0 ± 3.3 min) than for the SAX stack (7.5 ± 2.1 and 6.9 ± 3.6 min, respectively; P < 0.002). Bland–Altman analysis revealed lower mean differences, limits of agreement, and coefficients of variation for RV measurements obtained with the RHLA stack. Conclusions: RV functional analysis using a RHLA stack resulted in shorter analysis times and lower measurement variability than for a SAX stack orientation. PMID:28123842

  5. Magnetic Resonance Imaging and Other Imaging Modalities in Diagnostic and Tumor Response Evaluation.

    PubMed

    Lambregts, Doenja M J; Maas, Monique; Stokkel, Marcel P M; Beets-Tan, Regina G H

    2016-07-01

    Functional imaging is emerging as a valuable contributor to the clinical management of patients with rectal cancer. Techniques such as diffusion-weighted magnetic resonance imaging, perfusion imaging, and positron emission tomography can offer meaningful insights into tissue architecture, vascularity, and metabolism. Moreover, new techniques targeting other aspects of tumor biology are now being developed and studied. This study reviews the potential role of functional imaging for the diagnosis, treatment monitoring, and assessment of prognosis in patients with rectal cancer.

  6. Functional magnetic resonance imaging evaluation of lumbosacral radiculopathic pain.

    PubMed

    Koefman, Alex J; Licari, Melissa; Bynevelt, Michael; Lind, Christopher R P

    2016-10-01

    OBJECTIVE An objective biomarker for pain is yet to be established. Functional MRI (fMRI) is a promising neuroimaging technique that may reveal an objective radiological biomarker. The purpose of this study was to evaluate fMRI technology in the setting of lumbosacral radiculopathy and discuss its application in revealing a biomarker for pain in the future. METHODS A prospective, within-participant control study was conducted. Twenty participants with painful lumbosacral radiculopathy from intervertebral disc pathology were recruited. Functional imaging of the brain was performed during a randomly generated series of nonprovocative and provocative straight leg raise maneuvers. RESULTS With a statistical threshold set at p < 0.000001, 3 areas showed significant blood oxygen level-dependent (BOLD) signal change: right superior frontal gyrus (x = 2, y = 13, z = 48, k = 29, Brodmann area 6 [BA6]), left supramarginal cortex (x = -37, y = -44, z = 33, k = 1084, BA40), and left parietal cortex (x = -19, y = -41, z = 63, k = 354, BA5). With a statistical threshold set at p < 0.0002, 2 structures showed significant BOLD signal change: right putamen (x = 29, y = -11, z = 6, k = 72) and bilateral thalami (right: x = 23, y = -11, z = 21, k = 29; x = 8, y = -11, z = 9, k = 274; and left: x = -28, y = -32, z = 6, k = 21). CONCLUSIONS The results in this study compare with those in previous studies and suggest that fMRI technology can provide an objective assessment of the pain experience.

  7. Evaluation of Focal Ablation of Magnetic Resonance Imaging Defined Prostate Cancer Using Magnetic Resonance Imaging Controlled Transurethral Ultrasound Therapy with Prostatectomy as the Reference Standard.

    PubMed

    Ramsay, Elizabeth; Mougenot, Charles; Staruch, Robert; Boyes, Aaron; Kazem, Mohammad; Bronskill, Michael; Foster, Harry; Sugar, Linda; Haider, Masoom; Klotz, Laurence; Chopra, Rajiv

    2017-01-01

    We evaluated magnetic resonance imaging controlled transurethral ultrasound therapy as a treatment for magnetic resonance imaging defined focal prostate cancer using subsequent prostatectomy and histology as the reference standard. Five men completed this pilot study, which was approved by the institutional review board. Prior to radical prostatectomy focal tumors identified by magnetic resonance imaging were treated by coagulating targeted subtotal 3-dimensional volumes of prostate tissue using magnetic resonance imaging controlled transurethral focused ultrasound. Treatment was performed with a 3 Tesla clinical magnetic resonance imaging unit combined with modified clinical planning software for high intensity focused ultrasound therapy. After prostatectomy whole mount histological sections parallel to the magnetic resonance imaging treatment planes were used to compare magnetic resonance imaging measurements with thermal damage at the cellular level and, thus, evaluate treatment and target accuracy. Three-dimensional target volumes of 4 to 20 cc and with radii up to 35 mm from the urethra were treated successfully. Mean ± SD temperature control accuracy at the target boundary was -1.6 ± 4.8C and the mean spatial targeting accuracy achieved was -1.5 ± 2.8 mm. Mean treatment accuracy with respect to histology was -0.4 ± 1.7 mm with all index tumors falling inside the histological outer limit of thermal injury. Magnetic resonance imaging guided transurethral ultrasound therapy is capable of generating thermal coagulation and tumor destruction in targeted 3-dimensional angular sectors out to the prostate capsule for prostate glands up to 70 cc in volume. Ultrasound parameters needed to achieve ablation at the prostate capsule were determined, providing a foundation for future studies. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  8. Clinical application of radial magnetic resonance imaging for evaluation of rotator cuff tear.

    PubMed

    Honda, H; Morihara, T; Arai, Y; Horii, M; Ito, H; Furukawa, R; Kida, Y; Sukenari, T; Ikoma, K; Oda, R; Yamada, Y; Fujiwara, H; Kubo, T

    2015-10-01

    Magnetic resonance imaging is useful for evaluating the rotator cuff, but some tendinous insertions cannot be assessed using oblique sagittal, oblique coronal, and axial magnetic resonance (MR) images because of the presence of the partial volume effect. The purpose of this study was to determine whether radial-slice MR images could reveal normal rotator cuff insertions and rotator cuff tears more clearly than conventional MR images. The study included 18 subjects with normal rotator cuffs and 30 with rotator cuff tears. MR images of rotator cuff insertions sliced into radial, oblique coronal, and axial sections were obtained. The extent to which normal rotator cuff insertions and rotator cuff tears were visualized in each of the three MR images was evaluated. The top to posterior portions of the rotator cuff insertions from 0° to 120° could be visualized in the radial MR images. In comparison, the posterior portions of the rotator cuff insertions could not be visualized around 45° in both the oblique coronal and axial MR images. These findings demonstrate that radial MR images are superior to the oblique coronal and axial MR images regarding their ability to accurately visualize rotator cuff insertions. Radial MR images also revealed greater detail around 45° in the posterior area of the rotator cuff tears than the oblique coronal and axial MR images. Radial MR images are particularly useful for visualizing clinically important posterosuperior rotator cuff tears. Level III - Diagnostic study. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  9. Evaluation of the keyhole technique applied to the proton resonance frequency method for magnetic resonance temperature imaging.

    PubMed

    Han, YongHee; Mun, ChiWoong

    2011-11-01

    To evaluate the temporal and spatial resolution of magnetic resonance (MR) temperature imaging when using the proton resonance frequency (PRF) method combined with the keyhole technique. Tissue-mimicking phantom and swine muscle tissue were microwave-heated by a coaxial slot antenna. For the sake of MR hardware safety, MR images were sequentially acquired after heating the subjects using a spoiled gradient (SPGR) pulse sequence. Reference raw (k-space) data were collected before heating the subjects. Keyhole temperature images were reconstructed from full k-space data synthesized by combining the peripheral phase-encoding part of the reference raw data and the center phase-encoding keyhole part of the time sequential raw data. Each keyhole image was analyzed with thermal error, and the signal-to-noise ratio (SNR) was compared with the self-reference (nonkeyhole) images according to the number of keyhole phase-encoding (keyhole-data size) portions. In applied keyhole temperature images, smaller keyhole-data sizes led to more temperature error increases, but the SNR did not decreased comparably. Additionally, keyhole images with a keyhole-data size of <16 had significantly different temperatures compared with fully phase-encoded self-reference images (P < 0.05). The keyhole technique combined with the PRF method improves temporal resolution and SNR in the measurement of the temperature in the deeper parts of body in real time. Copyright © 2011 Wiley Periodicals, Inc.

  10. Magnetic resonance imaging (MRI) evaluation of residual breast tissue following mastectomy and reconstruction with silicone implants.

    PubMed

    Zippel, Douglas; Tsehmaister-Abitbol, Vered; Rundstein, Arie; Shalmon, Anat; Zbar, Andrew; Nardini, Gil; Novikov, Ilya; Sklair-Levy, Miri

    2015-01-01

    We present our use of magnetic resonance (MR) measurement to determine the amount of residual breast tissue (RBT) following total mastectomy with reconstruction. Breast MR images of 45 women who underwent surgery between January and November 2011 were reviewed. The cohort included therapeutic and prophylactic mastectomies. RBT was evaluated at four points with a digital caliper assessing T2-weighted and T1-weighted images. Patients undergoing mastectomy for carcinoma tended to have less RBT than in prophylactic surgery. Greater age and recent surgery both correlated with larger RBT. Variable thickness of RBT is demonstrable following mastectomy and implant reconstruction using MR imaging. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. Cine-magnetic resonance imaging evaluation of communication between middle cranial fossa arachnoid cysts and cisterns.

    PubMed

    Eguchi, T; Taoka, T; Nikaido, Y; Shiomi, K; Fujimoto, T; Otsuka, H; Takeuchi, H

    1996-06-01

    Cine-magnetic resonance (MR) imaging examinations were performed in 10 patients with middle cranial fossa arachnoid cysts to evaluate communication between the cysts and the normal cerebrospinal fluid (CSF) space. Eight of 10 patients were evaluated by time of flight cine-MR imaging, and two by phase contrast cine-MR imaging. Two patients underwent membranectomy of the cysts, and were evaluated both pre- and postoperatively. Computed tomography cisternography was used to confirm communication between the cysts and the surrounding cisterns. Pulsatile fluid motion within the cysts was present in all patients. However, marked fluid motion and jet flow between the cysts and the surrounding cisterns were only observed in communicating cysts. In the two patients who underwent membranectomy, postoperative examination found greater fluid motion and jet flow not previously present. Cine-MR imaging demonstration of marked pulsatile fluid motion accompanied by jet flow suggests that a cyst communicates with the normal CSF space.

  12. Magnetic resonance imaging of the chest in the evaluation of cancer patients: state of the art.

    PubMed

    Guimaraes, Marcos Duarte; Hochhegger, Bruno; Santos, Marcel Koenigkam; Santana, Pablo Rydz Pinheiro; Sousa, Arthur Soares; Souza, Luciana Soares; Marchiori, Edson

    2015-01-01

    Magnetic resonance imaging (MRI) has several advantages in the evaluation of cancer patients with thoracic lesions, including involvement of the chest wall, pleura, lungs, mediastinum, esophagus and heart. It is a quite useful tool in the diagnosis, staging, surgical planning, treatment response evaluation and follow-up of these patients. In the present review, the authors contextualize the relevance of MRI in the evaluation of thoracic lesions in cancer patients. Considering that MRI is a widely available method with high contrast and spatial resolution and without the risks associated with the use of ionizing radiation, its use combined with new techniques such as cine-MRI and functional methods such as perfusion- and diffusion-weighted imaging may be useful as an alternative tool with performance comparable or complementary to conventional radiological methods such as radiography, computed tomography and PET/CT imaging in the evaluation of patients with thoracic neoplasias.

  13. Magnetic resonance imaging of the chest in the evaluation of cancer patients: state of the art

    PubMed Central

    Guimaraes, Marcos Duarte; Hochhegger, Bruno; Santos, Marcel Koenigkam; Santana, Pablo Rydz Pinheiro; Sousa, Arthur Soares; Souza, Luciana Soares; Marchiori, Edson

    2015-01-01

    Magnetic resonance imaging (MRI) has several advantages in the evaluation of cancer patients with thoracic lesions, including involvement of the chest wall, pleura, lungs, mediastinum, esophagus and heart. It is a quite useful tool in the diagnosis, staging, surgical planning, treatment response evaluation and follow-up of these patients. In the present review, the authors contextualize the relevance of MRI in the evaluation of thoracic lesions in cancer patients. Considering that MRI is a widely available method with high contrast and spatial resolution and without the risks associated with the use of ionizing radiation, its use combined with new techniques such as cine-MRI and functional methods such as perfusion- and diffusion-weighted imaging may be useful as an alternative tool with performance comparable or complementary to conventional radiological methods such as radiography, computed tomography and PET/CT imaging in the evaluation of patients with thoracic neoplasias. PMID:25798006

  14. Evaluation of measures of technical image quality for intracranial magnetic resonance angiography.

    PubMed

    Chapman, B E; Goodrich, C K; Alexander, A L; Blatter, D D; Parker, D L

    1999-12-01

    We evaluate three measures of technical image quality for intracranial magnetic resonance angiography (MRA): (1) a two-alternative forced choice (2AFC) evaluation of vessel visibility, (2) vessel-to-background signal-difference-to-noise ratio (SDNR), and (3) observer ranking of the fidelity of vessel morphology compared to that in a gold standard image. The gold standard used for both the 2AFC and ranking measures is intraarterial catheter angiography. These measures are applied to healthy arterial segments. The 2AFC and SDNR measures directly evaluate the visibility of artery segments for which the existence is known from the gold standard images. We argue that (1) 2AFC evaluates the carrier signals on which any vascular disease process is modulated and provides an upper bound on the detectibility of vascular lesions, (2) SDNR is a predictor of 2AFC, and (3) ranking may be used to predict the relative performance of techniques in the detection of vascular lesions.

  15. Update on Magnetic Resonance Imaging and Ultrasound Evaluation of Crohn’s Disease

    PubMed Central

    Deepak, Parakkal; Kolbe, Amy B.; Fidler, Jeff L.; Fletcher, Joel G.; Knudsen, John M.

    2016-01-01

    Magnetic resonance enterography (MRE) and abdominal ultrasound are integral parts of multimodality assessments for patients with inflammatory bowel disease. Applications include assessing Crohn’s disease (CD) extent and severity, differentiating CD from ulcerative colitis, detecting CD complications, evaluating response to therapy, and demonstrating postoperative recurrence. Magnetic resonance imaging protocols are being developed that may reduce or eliminate the need for intravenous contrast agents and better differentiate inflammatory from fibrotic strictures. MRE scoring systems have been created to objectively quantify disease activity and response to therapy. By utilizing advanced sonographic imaging techniques, including ultrasound contrast and Doppler assessments, the role of abdominal ultrasonography in the evaluation and management of CD continues to expand. Abdominal ultrasound may function as a low-cost, point-of care assessment tool, especially in CD restricted to the terminal ileum and ileocolic anastomosis. PMID:27231453

  16. Quantifiable Imaging Biomarkers for Evaluation of the Posterior Cruciate Ligament Using 3-T Magnetic Resonance Imaging

    PubMed Central

    Wilson, Katharine J.; Surowiec, Rachel K.; Ho, Charles P.; Devitt, Brian M.; Fripp, Jurgen; Smith, W. Sean; Spiegl, Ulrich J.; Dornan, Grant J.; LaPrade, Robert F.

    2016-01-01

    Background: Quantitative magnetic resonance imaging (MRI) techniques, such as T2 and T2 star (T2*) mapping, have been used to evaluate ligamentous tissue in vitro and to identify significant changes in structural integrity of a healing ligament. These studies lay the foundation for a clinical study that uses quantitative mapping to evaluate ligaments in vivo, particularly the posterior cruciate ligament (PCL). To establish quantitative mapping as a clinical tool for identifying and evaluating chronic or acute PCL injuries, T2 and T2* values first must be determined for an asymptomatic population. Purpose: To quantify T2 and T2* mapping properties, including texture variables (entropy, variance, contrast, homogeneity), of the PCL in an asymptomatic population. It was hypothesized that biomarker values would be consistent throughout the ligament, as measured across 3 clinically relevant subregions (proximal, middle, and distal thirds) in the asymptomatic cohort. Study Design: Cross-sectional study; Level of evidence, 4. Methods: Unilateral knee MRI scans were acquired for 25 asymptomatic subjects with a 3.0-T MRI system using T2 and T2* mapping sequences in the sagittal plane. The PCL was manually segmented and divided into thirds (proximal, middle, and distal). Summary statistics for T2 and T2* values were calculated. Intra- and interrater reliability was assessed across 3 raters to 2 time points. Results: The asymptomatic PCL cohort had mean T2 values of 36.7, 29.2, and 29.6 ms in the distal, middle, and proximal regions, respectively. The distal PCL exhibited significantly higher mean, variance, and contrast and lower homogeneity of T2 values than the middle and proximal subregions (P < .05). T2* results exhibited substantial positive skew and were therefore presented as median and quartile (Q) values. Median T2* values were 7.3 ms (Q1-Q3, 6.8-8.9 ms), 7.3 ms (Q1-Q3, 7.0-8.5 ms), and 7.3 ms (Q1-Q3, 6.4-8.2 ms) in the distal, middle, and proximal subregions

  17. Magnetic resonance imaging and BMB score in the evaluation of bone involvement in Gaucher's disease patients.

    PubMed

    de Mello, Ricardo Andrade Fernandes; Mello, Melissa Bozzi Nonato; Pessanha, Laís Bastos

    2015-01-01

    To evaluate by magnetic resonance imaging changes in bone marrow of patients undergoing treatment for type I Gaucher's disease. Descriptive, cross-sectional study of Gaucher's disease patients submitted to 3 T magnetic resonance imaging of femurs and lumbar spine. The images were blindly reviewed and the findings were classified according to the semiquantitative bone marrow burden (BMB) scoring system. All of the seven evaluated patients (three men and four women) presented signs of bone marrow infiltration. Osteonecrosis of the femoral head was found in three patients, Erlenmeyer flask deformity in five, and no patient had vertebral body collapse. The mean BMB score was 11, ranging from 9 to 14. Magnetic resonance imaging is currently the method of choice for assessing bone involvement in Gaucher's disease in adults due to its high sensitivity to detect both focal and diffuse bone marrow changes, and the BMB score is a simplified method for semiquantitative analysis, without depending on advanced sequences or sophisticated hardware, allowing for the classification of the disease extent and assisting in the treatment monitoring.

  18. Clinical applications of advanced magnetic resonance imaging techniques for arthritis evaluation

    PubMed Central

    Martín Noguerol, Teodoro; Luna, Antonio; Gómez Cabrera, Marta; Riofrio, Alexie D

    2017-01-01

    Magnetic resonance imaging (MRI) has allowed a comprehensive evaluation of articular disease, increasing the detection of early cartilage involvement, bone erosions, and edema in soft tissue and bone marrow compared to other imaging techniques. In the era of functional imaging, new advanced MRI sequences are being successfully applied for articular evaluation in cases of inflammatory, infectious, and degenerative arthropathies. Diffusion weighted imaging, new fat suppression techniques such as DIXON, dynamic contrast enhanced-MRI, and specific T2 mapping cartilage sequences allow a better understanding of the physiopathological processes that underlie these different arthropathies. They provide valuable quantitative information that aids in their differentiation and can be used as potential biomarkers of articular disease course and treatment response. PMID:28979849

  19. [Functional magnetic resonance imaging for evaluation of radiation-induced renal damage].

    PubMed

    Haneder, S; Boda-Heggemann, J; Schoenberg, S O; Michaely, H J

    2012-03-01

    The diagnosis of radiation-induced (especially chronic) renal alterations/damage is difficult and currently relies primarily on clinical evaluation. The importance of renal diagnostic evaluation will increase continuously due to the increasing number of long-term survivors after radiotherapy. This article evaluates the potentia diagnostic contribution of magnetic resonance (MR) imaging with a focus on functional MRI. The following functional MRI approaches are briefly presented and evaluated: blood oxygenation level-dependent imaging (BOLD), diffusion-weighted imaging (DWI) or diffusion tensor imaging (DTI), MR perfusion measurements and (23)Na imaging. In summary, only DWI and contrast-enhanced MR perfusion currently seem to be suitable approaches for a broader, clinical implementation. However, up to now valid data from larger patient studies are lacking for both techniques in regard to radiation-induced renal alterations. The BOLD and (23)Na imaging procedures have a huge potential but are currently neither sufficiently evaluated with regard to radiation-induced renal alterations nor technically simple and reliable for implementation into the clinical routine.

  20. Performance of magnetic resonance imaging in the evaluation of first-time and reoperative primary hyperparathyroidism.

    PubMed

    Kluijfhout, Wouter P; Venkatesh, Shriya; Beninato, Toni; Vriens, Menno R; Duh, Quan-Yang; Wilson, David M; Hope, Thomas A; Suh, Insoo

    2016-09-01

    Preoperative imaging in patients with primary hyperparathyroidism and a previous parathyroid operation is essential; however, performance of conventional imaging is poor in this subgroup. Magnetic resonance imaging appears to be a good alternative, though overall evidence remains scarce. We retrospectively investigated the performance of magnetic resonance imaging in patients with and without a previous parathyroid operation, with a separate comparison for dynamic gadolinium-enhanced magnetic resonance imaging. All patients undergoing magnetic resonance imaging prior to parathyroidectomy for primary hyperparathyroidism (first time or recurrent) between January 2000 and August 2015 at a high-volume, tertiary care, referral center for endocrine operations were included. We compared the sensitivity and positive predictive value of magnetic resonance imaging with conventional ultrasound and sestamibi on a per-lesion level. A total of 3,450 patients underwent parathyroidectomy, of which 84 patients with recurrent (n = 10) or persistent (n = 74) disease and 41 patients with a primary operation were included. Magnetic resonance imaging had a sensitivity and positive predictive value of 79.9% and 84.7%, respectively, and performance was good in both patients with and without a previous parathyroid operation. Adding magnetic resonance imaging to the combination of ultrasound and sestamibi resulted in a significant increase in sensitivity from 75.2% to 91.5%. Dynamic magnetic resonance imaging produced excellent results in the reoperative group, with sensitivity and a positive predictive value of 90.1%. Technologic advances have enabled faster and more accurate magnetic resonance imaging protocols, making magnetic resonance imaging an excellent alternative modality without associated ionizing radiation. Our study shows that the sensitivity of multimodality imaging for parathyroid adenomas improved significantly with the use of conventional and dynamic magnetic resonance

  1. Utility of magnetic resonance imaging in the evaluation of left ventricular thickening.

    PubMed

    Fulton, Nicholas; Rajiah, Prabhakar

    2017-04-01

    Left ventricular (LV) thickening can be due to hypertrophy (concentric, asymmetric, eccentric) or remodelling (concentric or asymmetric). Pathological thickening may be caused by pressure overload, volume overload, infiltrative disorders, hypertrophic cardiomyopathy, athlete's heart or neoplastic infiltration. Magnetic resonance imaging (MRI) plays an important role in the comprehensive evaluation of LV thickening, including: establishing diagnosis, determining LV geometry, establishing aetiology, quantification, identifying prognostic factors, serial follow-up and treatment response. In this article, we review the aetiologies and pathophysiology of LV thickening, and demonstrate the comprehensive role of MRI in the evaluation of LV thickening.

  2. Phase II Evaluation of Magnetic Resonance Imaging Guided Focal Laser Ablation of Prostate Cancer.

    PubMed

    Eggener, Scott E; Yousuf, Ambereen; Watson, Sydeaka; Wang, Shiyang; Oto, Aytekin

    2016-12-01

    Magnetic resonance imaging guided focal laser ablation is an investigational strategy for the treatment of prostate cancer. This phase II evaluation of focal laser ablation included men with stage T1c-T2a, prostate specific antigen less than 15 ng/ml or prostate specific antigen density less than 0.15 ng/ml(3), Gleason 7 or less in 25% or less of biopsies and magnetic resonance imaging with 1 or 2 lesions concordant with biopsy detected cancer. At 3 months all patients underwent magnetic resonance imaging with biopsy of ablation zone(s). At 12 months all underwent magnetic resonance imaging and systematic biopsy. I-PSS (International Prostate Symptom Score) and SHIM (Sexual Health Inventory for Men) scores were collected before focal laser ablation, and at 1, 3 and 12 months. The primary end point was no cancer on the 3-month ablation zone biopsy. Secondary end points were safety, 12-month biopsy, and urinary and sexual function. In the 27 men median age was 62 years and mean prostate specific antigen was 4.4 ng/ml. Biopsy Gleason score was 6 in 23 patients (85%) and Gleason 7 in 4 (15%). Seven men (26%) had low volume Gleason 6 disease outside the intended ablation zone(s). At 3 months 26 patients (96%) had no evidence of cancer on magnetic resonance imaging guided biopsy of the ablation zone. No significant I-PSS changes were observed (each p >0.05). SHIM was lower at 1 month (p = 0.03), marginally lower at 3 months (p = 0.05) and without a significant difference at 12 months (p = 0.38). At 12-month biopsy cancer was identified in 10 patients (37%), including in the ablation zone(s) in 3 (11%) and outside the ablation zone(s) in 8 (30%) with cancer in and outside the ablation zone in 1. In select men with localized prostate cancer and visible magnetic resonance imaging lesions focal laser ablation has an acceptable morbidity profile and is associated with encouraging short-term oncologic outcomes. Significantly longer followup is mandatory to fully assess this

  3. Positional pelvic organ prolapse (POP) evaluation using open, weight-bearing magnetic resonance imaging (MRI).

    PubMed

    Friedman, Boris; Stothers, Lynn; Lazare, Darren; Macnab, Andrew

    2015-01-01

    Magnetic resonance imaging (MRI) of patients with pelvic organ prolapse (POP) is completed in the supine position. Open magnetic resonance imaging (MRO) uses vertical magnets, allowing imaging in a variety of upright postures. This pilot study used MRO to evaluate the change of prolapse in different positions compared to non-prolapsed images. In total, 11 women (6 POP, 5 controls) aged 24 to 65 years had 12 MRO images (midline sagittal pelvic line) consecutively when supine, sitting and standing with a full and empty bladder. Lengths between the lowest point of the bladder to the pubococcygeal (PC) and pubopromontoreal (PP) lines in each image were compared, and the ratio of bladder area under the PC and PP lines to the total bladder area. Significant elongation between the PC line and lowest point of the bladder was evident in subjects with POP comparing supine and standing images (p = 0.03), but not controls (p = 0.07). Similarly, this axis was significantly longer in cystocele subjects versus controls only in the standing position. Bladder area under the PC line was significantly increased between supine and standing positions only among subjects with cystocele (p < 0.01), and significantly larger among the study group in the standing position (p < 0.005), less significant in the supine position (p = 0.015), and not significant in the sitting position (p = 0.3). MRO imaging allows us to investigate the effects of upright position and weight bearing on the staging of POP. Imaging patients when sitting and standing identified that significant changes occur in the maximal descent of the bladder.

  4. Evaluation of the pituitary gland using magnetic resonance imaging: T1-weighted vs. VIBE imaging.

    PubMed

    Davis, M A; Castillo, M

    2013-06-01

    Volumetric interpolated breath-hold examination (VIBE) is used for abdominal imaging as a fast and efficient modality. Evaluation of brain lesions using VIBE is not common and its use for the pituitary gland has not yet been addressed. Our goal was to compare coronal T1-weighted (T1W) and VIBE images in patients undergoing studies of the pituitary gland. We hypothesized that, for this purpose, VIBE is superior to T1W images. T1W and VIBE images of the pituitary gland in 32 patients were evaluated. The two sequences were compared with specific attention to: contrast enhancement (gland and cavernous sinuses) and ability to view the anatomy of the cavernous sinuses. In patients with macroadenomas, visualization of the optic chiasm was also assessed. Images were rated as: VIBE being better, equal, or worse in comparison to T1W images. We also compared VIBE and T1W images specifically looking at micro/macro-adenomas and post-surgical patients. Statistical analysis was performed using chi-square statistics. Of the 32 patients, the VIBE sequence showed superior contrast enhancement in 18 patients, six were found as being equal to T1W, and in eight instances VIBE was found to be worse than T1W. These results were statistically significant (p=.02). When looking at micro/macro-adenomas and post-surgical patients specifically, there was a trend to VIBE being superior to T1W but these data were not statistically significant. Visualization of chiasm in macroadenomas was similar for both techniques. VIBE was significantly superior to T1W with respect to pituitary and cavernous sinus contrast enhancement and cavernous sinus anatomy. A trend towards VIBE being superior in the evaluation of adenomas (pre- and post-operative) was seen, but it was not statistically significant. This is likely due to the small population size.

  5. Brain tumor response to nimotuzumab treatment evaluated on magnetic resonance imaging.

    PubMed

    Dalmau, Evelio Rafael González; Cabal Mirabal, Carlos; Martínez, Giselle Saurez; Dávila, Agustín Lage; Suárez, José Carlos Ugarte; Cabanas Armada, Ricardo; Rodriguez Cruz, Gretel; Darias Zayas, Daniel; Castillo, Martha Ríos; Valle Garrido, Luis; Sotolongo, Luis Quevedo; Fernández, Mercedes Monzón

    2014-02-01

    Nimotuzumab, a humanized monoclonal antibody anti-epidermal growth factor receptor, has been shown to improve survival and quality of life in patients with pediatric malignant brain tumor. It is necessary, however, to increase the objective response criteria to define the optimal therapeutic schedule. The aim of this study was to obtain magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) quantitative information related to dimensions and morphology, molecular mobility and metabolic activity of the lesion and surroundings in order to evaluate any changes through time. Fourteen pediatric patients treated with nimotuzumab were evaluated on MRI and MRS for >2 years. Each patient was their own control. The MRI/MRS pulse sequence parameters were standardized to ensure experimental reproducibility. A total of 71.4% of patients had stable disease; 21.4% had objective response and 7.1% had progression of disease during the >2 year evaluation period. MRI/MRS data with clinical information provide a clearer picture of treatment response and confirm once again that nimotuzumab is effective in the treatment of pediatric brain tumor. These imaging procedures can be a useful tool for the clinical evaluation of study protocol in clinical practice. © 2013 The Authors. Pediatrics International © 2013 Japan Pediatric Society.

  6. Magnetic Resonance and Computed Tomography Imaging for the Evaluation of Pulmonary Hypertension

    PubMed Central

    Freed, Benjamin H.; Collins, Jeremy D.; François, Christopher J.; Barker, Alex J.; Cuttica, Michael J.; Chesler, Naomi C.; Markl, Michael; Shah, Sanjiv J.

    2016-01-01

    Imaging plays a central role in the diagnosis and management of all forms of pulmonary hypertension (PH). While Doppler echocardiography is essential for the evaluation of PH, its ability to optimally evaluate the right ventricle (RV) and pulmonary vasculature is limited by its 2D planar capabilities. Magnetic resonance imaging (MRI) and computed tomography (CT) are capable of determining the etiology and pathophysiology of PH, and can be very useful in the management of these patients. Exciting new techniques such as RV tissue characterization with T1 mapping, 4D flow of the RV and pulmonary arteries, and CT lung perfusion imaging are paving the way for a new era of imaging in PH. These imaging modalities complement echocardiography and invasive hemodynamic testing, and may be useful as surrogate endpoints for early-phase PH clinical trials. Here we discuss the role of MRI and CT in the diagnosis and management of PH, including current uses and novel research applications, and we discuss the role of value-based imaging in PH. PMID:27282439

  7. Myocardial ischemia evaluation with dual-source computed tomography: comparison with magnetic resonance imaging.

    PubMed

    Delgado, Carlos; Vázquez, María; Oca, Roque; Vilar, Manuel; Trinidad, Carmen; Sanmartin, Marcelo

    2013-11-01

    Computed tomography does not accurately determine which coronary lesions lead to myocardial ischemia and consequently further tests are required to evaluate ischemia induction. The aim of this study was to compare diagnostic accuracy between dual-energy computed tomography and magnetic resonance imaging in the assessment of myocardial perfusion and viability in patients suspected of coronary artery disease. A prospective study was performed in 56 consecutive patients (39 men [69.6%]; mean age [standard deviation], 63 [10]; range, 23-81). Computed tomography was performed with the following protocol: 1, adenosine stress perfusion; 2, coronary angiography; and 3, delayed enhancement. Magnetic resonance imaging for the evaluation of stress perfusion and delayed enhancement was performed within 30 days. Two observers in consensus analyzed the perfusion and delayed enhancement images. We studied 952 myocardial segments and 168 vascular territories. In a per-segment analysis, the sensitivity, specificity, and positive and negative predictive values of computed tomography compared with magnetic resonance were 76%, 99%, 89%, and 98% for perfusion defects, and 64%, 99%, 82%, and 99% for delayed enhancement, respectively. In a per-vascular territory analysis, the same measures were 78%, 97%, 86%, and 95% for perfusion defects, and 72%, 99%, 93%, and 97% for delayed enhancement, respectively. The mean radiation dose was 8.2 (2) mSv. Dual-source computed tomography may allow accurate and concomitant evaluation of perfusion defects and myocardial viability and analysis of coronary anatomy. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  8. Comparison of magnetic resonance imaging and ultrasonography in the evaluation of abdominal aortic aneurysms.

    PubMed

    Amparo, E G; Hoddick, W K; Hricak, H; Sollitto, R; Justich, E; Filly, R A; Higgins, C B

    1985-02-01

    Magnetic resonance imaging (MRI) was used to evaluate abdominal aortic aneurysms in 27 patients. The findings were compared retrospectively with CT, ultrasound (US), and angiography in 17 cases and prospectively with US in 10 cases. MRI identified the renal arteries in all cases, demonstrated involvement at or above the origin of the renal arteries in eight patients, and showed extension of the aneurysm into the iliac arteries in 12 cases. The outer dimension of the aneurysm, the diameter of the residual lumen, and the length of the aneurysm were measured easily from the MR images. The measurements of transverse dimension of the abdominal aortic aneurysm were similar for MRI, CT, and US. MRI more accurately defined extension above the renal arteries and below the aortic bifurcation. It is concluded that MRI provides the necessary information for the surveillance and preoperative evaluation of abdominal aortic aneurysms.

  9. Value of ultrasound and magnetic resonance imaging in the preoperative evaluation of suspected ovarian masses.

    PubMed

    Huber, Sabine; Medl, Michael; Baumann, Louis; Czembirek, Heinrich

    2002-01-01

    The stage of ovarian carcinoma at diagnosis directly affects prognosis. Thus, thorough pretreatment evaluation is basic to the successful management of suspected ovarian masses. Among currently available imaging techniques in characterization of suspected ovarian neoplasms, sonography (US) is indisputedly the primary imaging approach. When US is inconclusive, magnetic resonance imaging (MRI) is generally prefered to computed tomography (CT). 93 patients, who on the basis of clinical findings were suspected to have ovarian cancer and who were scheduled for subsequent surgical staging underwent preoperative transvaginal and abdominal ultrasound as well as magnetic resonance imaging in a prospective comparative study. US and MR images were evaluated for their information on the characterization and staging of the ovarian masses. MRI correctly characterized malignant and benign tumors in 89% of cases versus 85% by ultrasound. The site of the primary tumor was correctly diagnosed in 94% of cases by MRI vs. 90% by ultrasound. For US, the positive predictive value was 85%, the negative predictive value 73% vs. 92% and 89% for MRI. In differentiation of nonadvanced disease from advanced malignancy, US showed a false-positive rate of 0.416 and false-negative rate of 0.258 vs. 0.125 and 0.032 respectively, for MRI. MRI was superior in diagnosis of malignant ovarian masses though US, too, performed well at lesion detection and characterization. With regard to tumor staging MRI is emerging as a problem-solving modality and may allow more appropriate clinical decisions to be made in selected patients with complex adnexal disease.

  10. Cardiovascular magnetic resonance imaging: clinical implications in the evaluation of connective tissue diseases

    PubMed Central

    Mavrogeni, Sophie; Markousis-Mavrogenis, George; Koutsogeorgopoulou, Loukia; Kolovou, Genovefa

    2017-01-01

    Cardiovascular magnetic resonance imaging is a recently developed noninvasive, nonradiating, operator-independent technique that has been successfully used for the evaluation of congenital heart disease, valvular and pericardial diseases, iron overload, cardiomyopathies, great and coronary vessel diseases, cardiac inflammation, stress–rest myocardial perfusion, and fibrosis. Rheumatoid arthritis and other spondyloarthropathies, systemic lupus erythematosus, inflammatory myopathies, mixed connective tissue diseases (CTDs), systemic sclerosis, vasculitis, and sarcoidosis are among CTDs with serious cardiovascular involvement; this is due to multiple causative factors such as myopericarditis, micro/macrovascular disease, coronary artery disease, myocardial fibrosis, pulmonary hypertension, and finally heart failure. The complicated pathophysiology and the high cardiovascular morbidity and mortality of CTDs demand a versatile, noninvasive, nonradiative diagnostic tool for early cardiovascular diagnosis, risk stratification, and treatment follow-up. Cardiovascular magnetic resonance imaging can detect early silent cardiovascular lesions, assess disease acuteness, and reliably evaluate the effect of both cardiac and rheumatic medication in the cardiovascular system, due to its capability to perform tissue characterization and its high spatial resolution. However, until now, high cost; lack of interaction between cardiologists, radiologists, and rheumatologists; lack of availability; and lack of experts in the field have limited its wider adoption in the clinical practice. PMID:28546762

  11. Quantitative morphologic evaluation of magnetic resonance imaging during and after treatment of childhood leukemia

    PubMed Central

    Reddick, Wilburn E.; Laningham, Fred H.; Glass, John O.; Pui, Ching-Hon

    2008-01-01

    Introduction Medical advances over the last several decades, including CNS prophylaxis, have greatly increased survival in children with leukemia. As survival rates have increased, clinicians and scientists have been afforded the opportunity to further develop treatments to improve the quality of life of survivors by minimizing the long-term adverse effects. When evaluating the effect of antileukemia therapy on the developing brain, magnetic resonance (MR) imaging has been the preferred modality because it quantifies morphologic changes objectively and noninvasively. Method and results Computer-aided detection of changes on neuroimages enables us to objectively differentiate leukoencephalopathy from normal maturation of the developing brain. Quantitative tissue segmentation algorithms and relaxometry measures have been used to determine the prevalence, extent, and intensity of white matter changes that occur during therapy. More recently, diffusion tensor imaging has been used to quantify microstructural changes in the integrity of the white matter fiber tracts. MR perfusion imaging can be used to noninvasively monitor vascular changes during therapy. Changes in quantitative MR measures have been associated, to some degree, with changes in neurocognitive function during and after treatment Conclusion In this review, we present recent advances in quantitative evaluation of MR imaging and discuss how these methods hold the promise to further elucidate the pathophysiologic effects of treatment for childhood leukemia. PMID:17653705

  12. Evaluation of five diffeomorphic image registration algorithms for mouse brain magnetic resonance microscopy.

    PubMed

    Fu, Zhenrong; Lin, Lan; Tian, Miao; Wang, Jingxuan; Zhang, Baiwen; Chu, Pingping; Li, Shaowu; Pathan, Muhammad Mohsin; Deng, Yulin; Wu, Shuicai

    2017-06-14

    The development of genetically engineered mouse models for neuronal diseases and behavioural disorders have generated a growing need for small animal imaging. High-resolution magnetic resonance microscopy (MRM) provides powerful capabilities for noninvasive studies of mouse brains, while avoiding some limits associated with the histological procedures. Quantitative comparison of structural images is a critical step in brain imaging analysis, which highly relies on the performance of image registration techniques. Nowadays, there is a mushrooming growth of human brain registration algorithms, while fine-tuning of those algorithms for mouse brain MRMs is rarely addressed. Because of their topology preservation property and outstanding performance in human studies, diffeomorphic transformations have become popular in computational anatomy. In this study, we specially tuned five diffeomorphic image registration algorithms [DARTEL, geodesic shooting, diffeo-demons, SyN (Greedy-SyN and geodesic-SyN)] for mouse brain MRMs and evaluated their performance using three measures [volume overlap percentage (VOP), residual intensity error (RIE) and surface concordance ratio (SCR)]. Geodesic-SyN performed significantly better than the other methods according to all three different measures. These findings are important for the studies on structural brain changes that may occur in wild-type and transgenic mouse brains. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  13. Contactless Abdominal Fat Reduction With Selective RF™ Evaluated by Magnetic Resonance Imaging (MRI): Case Study.

    PubMed

    Downie, Jeanine; Kaspar, Miroslav

    2016-04-01

    Noninvasive body shaping methods seem to be an ascending part of the aesthetics market. As a result, the pressure to develop reliable methods for the collection and presentation of their results has also increased. The most used techniques currently include ultrasound measurements of fat thickness in the treated area, caliper measurements, bioimpedance-based scale measurements or circumferential tape measurements. Although these are the most used techniques, almost all of them have some limitations in reproducibility and/or accuracy. This study shows Magnetic Resonance Imaging (MRI) as the new method for the presentation of results in the body shaping industry. Six subjects were treated by a contactless selective radiofrequency device (BTL Vanquish ME, BTL Industries Inc., Boston, MA). The MRI fat thickness was measured at the baseline and at 4-weeks following the treatment. In addition to MRI images and measurements, digital photographs and anthropometric evaluations such as weight, abdominal circumference, and caliper fat thickness measurements were recorded. Abdominal fat thickness measurements from the MRI were performed from the same slices determined by the same tissue artefacts. The MRI fat thickness difference between the baseline measurement and follow up visit showed an average reduction of 5.36 mm as calculated from the data of 5 subjects. One subject dropped out of study due to non-study related issues. The results were statistically significant based on the Student's T-test evaluation. Magnetic resonance imaging abdominal fat thickness measurements seems to be the best method for the evaluation of fat thickness reduction after non-invasive body shaping treatments. In this study, this method shows average fat thickness reduction of 5.36 mm while the weight of the subjects didn't change significantly. A large spot size measuring 1317 cm(2) (204 square inches) covers the abdomen flank to flank. The average thickness of 5.36 mm of the fat layer reduced

  14. Incidence and Evaluation of Incidental Abnormal Bone Marrow Signal on Magnetic Resonance Imaging

    PubMed Central

    Shah, Gunjan L.; Rosenberg, Aaron S.; Jarboe, Jamie; Klein, Andreas; Cossor, Furha

    2014-01-01

    Purpose. The increased use of magnetic resonance imaging (MRI) has resulted in reports of incidental abnormal bone marrow (BM) signal. Our goal was to determine the evaluation of an incidental abnormal BM signal on MRI and the prevalence of a subsequent oncologic diagnosis. Methods. We conducted a retrospective cohort study of patients over age 18 undergoing MRI between May 2005 and October 2010 at Tufts Medical Center (TMC) with follow-up through November 2013. The electronic medical record was queried to determine imaging site, reason for scan, evaluation following radiology report, and final diagnosis. Results. 49,678 MRIs were done with 110 patients meeting inclusion criteria. Twenty two percent underwent some evaluation, most commonly a complete blood count, serum protein electrophoresis, or bone scan. With median follow-up of 41 months, 6% of patients were diagnosed with malignancies including multiple myeloma, non-Hodgkins lymphoma, metastatic non-small cell lung cancer, and metastatic adenocarcinoma. One patient who had not undergone evaluation developed breast cancer 24 months after the MRI. Conclusions. Incidentally noted abnormal or heterogeneous bone marrow signal on MRI was not inconsequential and should prompt further evaluation. PMID:25374938

  15. Comparison of gradient echo with spin echo magnetic resonance imaging and echocardiography in the evaluation of major aortopulmonary collateral arteries.

    PubMed

    Vick, G W; Wendt, R E; Rokey, R

    1994-05-01

    This study compared gradient echo magnetic resonance imaging, spin echo magnetic resonance imaging, echocardiography, and echocardiography with x-ray cineangiography in the evaluation of major aortopulmonary collateral arteries. Twelve patients (ages 9 months to 35 years, mean 11 +/- 11 years) with known or suspected major aortopulmonary collateral arteries were studied. The aortic insertion and proximal course of 29 major aortopulmonary collateral arteries demonstrated by x-ray contrast angiography were shown in all 29 cases by gradient echo magnetic resonance imaging but in only 23 of the 29 cases by spin echo magnetic resonance imaging. Color Doppler-echocardiography detected aortopulmonary collateral arteries in four patients but did not define the proximal course or distal anatomy. Gradient echo images of distal aortopulmonary collateral anatomy were qualitatively superior to spin echo images. The contrast-to-noise ratio between the vessel lumen and adjacent lung was greater for gradient echo (6.06 +/- 2.91) than for spin echo (1.45 +/- 1.13)(p < 0.05). Gradient echo magnetic resonance imaging is a useful method for identification and characterization of aortopulmonary collateral arteries in patients of all ages and is superior to spin echo magnetic resonance imaging and echocardiography.

  16. A Pilot Study to Evaluate the Role of Magnetic Resonance Imaging for Prostate Cancer Screening in the General Population.

    PubMed

    Nam, Robert K; Wallis, Christopher J D; Stojcic-Bendavid, Jessica; Milot, Laurent; Sherman, Christopher; Sugar, Linda; Haider, Masoom A

    2016-08-01

    To our knowledge the role of magnetic resonance imaging as a first line screening test for prostate cancer is unknown. We performed a pilot study to evaluate the feasibility of prostate magnetic resonance imaging as the primary screening test for prostate cancer. We recruited unselected men from the general population. Prostate multiparametric magnetic resonance imaging and random or targeted biopsies were performed in all patients, in addition to prostate specific antigen testing. We compared the performance of prostate magnetic resonance imaging and prostate specific antigen test results to predict prostate cancer. Of the 47 recruited patients 18 (38.3%) had cancer while 29 (61.7%) had no evidence of cancer. The adjusted OR of prostate cancer was significantly higher for magnetic resonance imaging score than for prostate specific antigen level (2.7, 95% CI 1.4-5.4, p = 0.004 vs 1.1, 95% CI 0.9-1.4, p = 0.21). Among the 30 patients with a normal prostate specific antigen (less than 4.0 ng/ml) the positive predictive value in those with a magnetic resonance imaging score of 4 or more was 66.7% (6 of 9) and the negative predictive value in those with a magnetic resonance imaging score of 3 or less was 85.7% (18 of 21, p = 0.004). In this pilot study we determined the feasibility of using multiparametric prostate magnetic resonance imaging as the primary screening test for prostate cancer. Initial results showed that prostate magnetic resonance imaging was better to predict prostate cancer than prostate specific antigen in an unselected sample of the general population. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  17. Six-minute magnetic resonance imaging protocol for evaluation of acute ischemic stroke: pushing the boundaries.

    PubMed

    Nael, Kambiz; Khan, Rihan; Choudhary, Gagandeep; Meshksar, Arash; Villablanca, Pablo; Tay, Jennifer; Drake, Kendra; Coull, Bruce M; Kidwell, Chelsea S

    2014-07-01

    If magnetic resonance imaging (MRI) is to compete with computed tomography for evaluation of patients with acute ischemic stroke, there is a need for further improvements in acquisition speed. Inclusion criteria for this prospective, single institutional study were symptoms of acute ischemic stroke within 24 hours onset, National Institutes of Health Stroke Scale ≥3, and absence of MRI contraindications. A combination of echo-planar imaging (EPI) and a parallel acquisition technique were used on a 3T magnetic resonance (MR) scanner to accelerate the acquisition time. Image analysis was performed independently by 2 neuroradiologists. A total of 62 patients met inclusion criteria. A repeat MRI scan was performed in 22 patients resulting in a total of 84 MRIs available for analysis. Diagnostic image quality was achieved in 100% of diffusion-weighted imaging, 100% EPI-fluid attenuation inversion recovery imaging, 98% EPI-gradient recalled echo, 90% neck MR angiography and 96% of brain MR angiography, and 94% of dynamic susceptibility contrast perfusion scans with interobserver agreements (k) ranging from 0.64 to 0.84. Fifty-nine patients (95%) had acute infarction. There was good interobserver agreement for EPI-fluid attenuation inversion recovery imaging findings (k=0.78; 95% confidence interval, 0.66-0.87) and for detection of mismatch classification using dynamic susceptibility contrast-Tmax (k=0.92; 95% confidence interval, 0.87-0.94). Thirteen acute intracranial hemorrhages were detected on EPI-gradient recalled echo by both observers. A total of 68 and 72 segmental arterial stenoses were detected on contrast-enhanced MR angiography of the neck and brain with k=0.93, 95% confidence interval, 0.84 to 0.96 and 0.87, 95% confidence interval, 0.80 to 0.90, respectively. A 6-minute multimodal MR protocol with good diagnostic quality is feasible for the evaluation of patients with acute ischemic stroke and can result in significant reduction in scan time rivaling that

  18. Application safety evaluation of the radio frequency identification tag under magnetic resonance imaging.

    PubMed

    Fei, Xiaolu; Li, Shanshan; Gao, Shan; Wei, Lan; Wang, Lihong

    2014-09-04

    Radio Frequency Identification(RFID) has been widely used in healthcare facilities, but it has been paid little attention whether RFID applications are safe enough under healthcare environment. The purpose of this study is to assess the effects of RFID tags on Magnetic Resonance (MR) imaging in a typical electromagnetic environment in hospitals, and to evaluate the safety of their applications. A Magphan phantom was used to simulate the imaging objects, while active RFID tags were placed at different distances (0, 4, 8, 10 cm) from the phantom border. The phantom was scanned by using three typical sequences including spin-echo (SE) sequence, gradient-echo (GRE) sequence and inversion-recovery (IR) sequence. The quality of the image was quantitatively evaluated by using signal-to-noise ratio (SNR), uniformity, high-contrast resolution, and geometric distortion. RFID tags were read by an RFID reader to calculate their usable rate. RFID tags can be read properly after being placed in high magnetic field for up to 30 minutes. SNR: There were no differences between the group with RFID tags and the group without RFID tags using SE and IR sequence, but it was lower when using GRE sequence.Uniformity: There was a significant difference between the group with RFID tags and the group without RFID tags using SE and GRE sequence. Geometric distortion and high-contrast resolution: There were no obvious differences found. Active RFID tags can affect MR imaging quality, especially using the GRE sequence. Increasing the distance from the RFID tags to the imaging objects can reduce that influence. When the distance was longer than 8 cm, MR imaging quality were almost unaffected. However, the Gradient Echo related sequence is not recommended when patients wear a RFID wristband.

  19. Cavernosal nerve functionality evaluation after magnetic resonance imaging-guided transurethral ultrasound treatment of the prostate.

    PubMed

    Sammet, Steffen; Partanen, Ari; Yousuf, Ambereen; Sammet, Christina L; Ward, Emily V; Wardrip, Craig; Niekrasz, Marek; Antic, Tatjana; Razmaria, Aria; Farahani, Keyvan; Sokka, Shunmugavelu; Karczmar, Gregory; Oto, Aytekin

    2015-12-28

    To evaluate the feasibility of using therapeutic ultrasound as an alternative treatment option for organ-confined prostate cancer. In this study, a trans-urethral therapeutic ultrasound applicator in combination with 3T magnetic resonance imaging (MRI) guidance was used for real-time multi-planar MRI-based temperature monitoring and temperature feedback control of prostatic tissue thermal ablation in vivo. We evaluated the feasibility and safety of MRI-guided trans-urethral ultrasound to effectively and accurately ablate prostate tissue while minimizing the damage to surrounding tissues in eight canine prostates. MRI was used to plan sonications, monitor temperature changes during therapy, and to evaluate treatment outcome. Real-time temperature and thermal dose maps were calculated using the proton resonance frequency shift technique and were displayed as two-dimensional color-coded overlays on top of the anatomical images. After ultrasound treatment, an evaluation of the integrity of cavernosal nerves was performed during prostatectomy with a nerve stimulator that measured tumescence response quantitatively and indicated intact cavernous nerve functionality. Planned sonication volumes were visually correlated to MRI ablation volumes and corresponding histo-pathological sections after prostatectomy. A total of 16 sonications were performed in 8 canines. MR images acquired before ultrasound treatment were used to localize the prostate and to prescribe sonication targets in all canines. Temperature elevations corresponded within 1 degree of the targeted sonication angle, as well as with the width and length of the active transducer elements. The ultrasound treatment procedures were automatically interrupted when the temperature in the target zone reached 56 °C. In all canines erectile responses were evaluated with a cavernous nerve stimulator post-treatment and showed a tumescence response after stimulation with an electric current. These results indicated intact

  20. Cavernosal nerve functionality evaluation after magnetic resonance imaging-guided transurethral ultrasound treatment of the prostate

    PubMed Central

    Sammet, Steffen; Partanen, Ari; Yousuf, Ambereen; Sammet, Christina L; Ward, Emily V; Wardrip, Craig; Niekrasz, Marek; Antic, Tatjana; Razmaria, Aria; Farahani, Keyvan; Sokka, Shunmugavelu; Karczmar, Gregory; Oto, Aytekin

    2015-01-01

    AIM: To evaluate the feasibility of using therapeutic ultrasound as an alternative treatment option for organ-confined prostate cancer. METHODS: In this study, a trans-urethral therapeutic ultrasound applicator in combination with 3T magnetic resonance imaging (MRI) guidance was used for real-time multi-planar MRI-based temperature monitoring and temperature feedback control of prostatic tissue thermal ablation in vivo. We evaluated the feasibility and safety of MRI-guided trans-urethral ultrasound to effectively and accurately ablate prostate tissue while minimizing the damage to surrounding tissues in eight canine prostates. MRI was used to plan sonications, monitor temperature changes during therapy, and to evaluate treatment outcome. Real-time temperature and thermal dose maps were calculated using the proton resonance frequency shift technique and were displayed as two-dimensional color-coded overlays on top of the anatomical images. After ultrasound treatment, an evaluation of the integrity of cavernosal nerves was performed during prostatectomy with a nerve stimulator that measured tumescence response quantitatively and indicated intact cavernous nerve functionality. Planned sonication volumes were visually correlated to MRI ablation volumes and corresponding histo-pathological sections after prostatectomy. RESULTS: A total of 16 sonications were performed in 8 canines. MR images acquired before ultrasound treatment were used to localize the prostate and to prescribe sonication targets in all canines. Temperature elevations corresponded within 1 degree of the targeted sonication angle, as well as with the width and length of the active transducer elements. The ultrasound treatment procedures were automatically interrupted when the temperature in the target zone reached 56 °C. In all canines erectile responses were evaluated with a cavernous nerve stimulator post-treatment and showed a tumescence response after stimulation with an electric current. These

  1. Magnetic resonance imaging evaluation of muscle usage associated with three exercises for rotator cuff rehabilitation.

    PubMed

    Horrigan, J M; Shellock, F G; Mink, J H; Deutsch, A L

    1999-10-01

    Methods of determining muscle usage for exercises involving rotator cuff muscles are limited. Therefore, this investigation used magnetic resonance imaging (MRI) to evaluate the effect of three different exercises used for rehabilitation of the rotator cuff. Five normal volunteer subjects (3 men, 2 women, mean age 31.4 yr) were studied. The exercises were scaption with internal rotation (SIR), military press (MP), and side-lying 45 degrees abduction (SLA). MR imaging was performed immediately before and after exercise using a "fast" spin echo STIR sequence and oblique coronal plane imaging. Changes in signal intensity pre- and post-exercise were measured at comparable section locations for the MR images of the supraspinatus, infraspinatus, teres minor, subscapularis, deltoid, and trapezius. The SLA showed the greatest increase in signal intensity in all the muscles (percent change, P < 0.01) except for the trapezius, which was used more by the MP and SIR. None of the exercises activated the teres minor (percent change, P = not significant). These findings have important implications in efficacy of physical rehabilitation of the rotator cuff and avoidance of subacromial impingement exercise motions.

  2. Correlative magnetic resonance imaging in the evaluation of aortic and pulmonary artery abnormalities

    SciTech Connect

    Risius, B.; O'Donnell, J.K.; Geisinger, M.A.; Zelch, M.G.; George, C.R.; Graor, R.A.; Moodie, D.S.

    1985-05-01

    Magnetic resonance imaging (MRI) yields excellent quality images of the cardiovascular system utilizing the inherent natural contrast between flowing blood and the surrounding anatomic structures. To evaluate the clinical usefulness of MRI in the noninvasive diagnosis of large vessel disorders, the authors have performed MRI on 40 pts with either aortic or pulmonary artery abnormalities (18 thoracic or abdominal aortic aneurysms, 8 aorto-occlusive disease, 6 dissecting aneurysms, 4 Marfan's syndrome, 2 pulmonary artery aneurysms 1 pulmonary artery occlusion, 1 aortic coarctation). Images were obtained in the transverse, coronal and sagital body planes utilizing a 0.6T superconductive magnet. Cardiac and/or respiratory gating was employed in most cases. Correlation was made for all studies with conventional or digital subtraction angiography, computed tomography, and/or ultrasound. The diagnostic information obtained by MRI equaled or exceeded that obtained by other imaging techniques except for the few cases where cardiac arrhythmias precluded adequate gated acquisition. All aneurysms and their relationships to adjacent structures were readily demonstrated as were the presence or absence of mural thrombi and dissecting intimal flaps. Angiographically demonstrated atherosclerotic plaques and luminal stenoses were seen by MRI in all patients without arrhythmias. The authors concluded that MRI is a powerful noninvasive diagnostic aid in the delineation of large vessel disorders, especially where knowledge of anatomic interrelationships can guide surgical or other interventional planning.

  3. Preliminary evaluation of magnetic resonance fresh blood imaging for diagnosis of Budd-Chiari syndrome.

    PubMed

    Ren, Ke; Xu, Ke; Sun, Wen-ge; Chen, Yu-shuai; Qi, Xi-xun; Li, Ran-liang; Jin, An-yu

    2007-01-20

    Budd-Chiari syndrome (BCS) is a rare disease with portal hypertension caused by the blockage of the hepatic vein and/or the inferior vena cava (IVC). Angiography is the "golden standard" for diagnosis, but it is an invasive examination. To assess the diagnostic value of a fresh blood imaging (FBI) relative to BCS, we used a magnetic resonance angiography (MRA) with an FBI sequence for a preoperative evaluation of the BCS patients in this study. Fifty patients who were suspected of having BCS after they had been checked by a B-ultrasound were studied. 2D and 3D FBI were performed on a 1.5T superconductive MR scanner. Original images were rebuilt using a maximal intensity projection (MIP) method on the console. Two doctors reviewed all images before they learned of the angiography results. We then compared the diagnoses obtained from the FBI and angiography results to evaluate the diagnostic value of the FBI. Forty-one patients were diagnosed as BCS and 9 as non-BCS based on an angiography. The FBI correctly diagnosed 38 patients, incorrectly diagnosed 1 patient, and missed diagnosis in 3 patients. Thus, the diagnostic sensitivity of the FBI is 93% (38/41), the specificity is 89% (8/9) and the accuracy is 92% (46/50). The FBI images of the 13 membranous stenoses of the IVC showed a sudden stenosis of the post-liver segment of the IVC. The Images of the 5 patients with a membranous obstruction of the IVC showed IVC thickening and an absence of blood signals in the post-hepatic segment of the IVC. The images of the 4 patients with the segmental thrombosis of the IVC showed abnormal and intermittent signals in the IVC. The images of the 6 patients with a simple hepatic vein obstruction showed obstructive hepatic veins. The images of the 6 patients with the stenosis of both the IVC and the hepatic veins showed the stenosis of the IVC, the thickening of the hepatic veins and the formation of a compensatory circulation within the liver. Lastly, the images of the 7 patients

  4. Diagnostic accuracy of susceptibility-weighted magnetic resonance imaging for the evaluation of pineal gland calcification

    PubMed Central

    Böker, Sarah M.; Bender, Yvonne Y.; Diederichs, Gerd; Fallenberg, Eva M.; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R.

    2017-01-01

    Objectives To determine the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the detection of pineal gland calcifications (PGC) compared to conventional magnetic resonance imaging (MRI) sequences, using computed tomography (CT) as a reference standard. Methods 384 patients who received a 1.5 Tesla MRI scan including SWMR sequences and a CT scan of the brain between January 2014 and October 2016 were retrospectively evaluated. 346 patients were included in the analysis, of which 214 showed PGC on CT scans. To assess correlation between imaging modalities, the maximum calcification diameter was used. Sensitivity and specificity and intra- and interobserver reliability were calculated for SWMR and conventional MRI sequences. Results SWMR reached a sensitivity of 95% (95% CI: 91%-97%) and a specificity of 96% (95% CI: 91%-99%) for the detection of PGC, whereas conventional MRI achieved a sensitivity of 43% (95% CI: 36%-50%) and a specificity of 96% (95% CI: 91%-99%). Detection rates for calcifications in SWMR and conventional MRI differed significantly (95% versus 43%, p<0.001). Diameter measurements between SWMR and CT showed a close correlation (R2 = 0.85, p<0.001) with a slight but not significant overestimation of size (SWMR: 6.5 mm ± 2.5; CT: 5.9 mm ± 2.4, p = 0.02). Interobserver-agreement for diameter measurements was excellent on SWMR (ICC = 0.984, p < 0.0001). Conclusions Combining SWMR magnitude and phase information enables the accurate detection of PGC and offers a better diagnostic performance than conventional MRI with CT as a reference standard. PMID:28278291

  5. Diagnostic accuracy of susceptibility-weighted magnetic resonance imaging for the evaluation of pineal gland calcification.

    PubMed

    Adams, Lisa C; Böker, Sarah M; Bender, Yvonne Y; Diederichs, Gerd; Fallenberg, Eva M; Wagner, Moritz; Hamm, Bernd; Makowski, Marcus R

    2017-01-01

    To determine the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the detection of pineal gland calcifications (PGC) compared to conventional magnetic resonance imaging (MRI) sequences, using computed tomography (CT) as a reference standard. 384 patients who received a 1.5 Tesla MRI scan including SWMR sequences and a CT scan of the brain between January 2014 and October 2016 were retrospectively evaluated. 346 patients were included in the analysis, of which 214 showed PGC on CT scans. To assess correlation between imaging modalities, the maximum calcification diameter was used. Sensitivity and specificity and intra- and interobserver reliability were calculated for SWMR and conventional MRI sequences. SWMR reached a sensitivity of 95% (95% CI: 91%-97%) and a specificity of 96% (95% CI: 91%-99%) for the detection of PGC, whereas conventional MRI achieved a sensitivity of 43% (95% CI: 36%-50%) and a specificity of 96% (95% CI: 91%-99%). Detection rates for calcifications in SWMR and conventional MRI differed significantly (95% versus 43%, p<0.001). Diameter measurements between SWMR and CT showed a close correlation (R2 = 0.85, p<0.001) with a slight but not significant overestimation of size (SWMR: 6.5 mm ± 2.5; CT: 5.9 mm ± 2.4, p = 0.02). Interobserver-agreement for diameter measurements was excellent on SWMR (ICC = 0.984, p < 0.0001). Combining SWMR magnitude and phase information enables the accurate detection of PGC and offers a better diagnostic performance than conventional MRI with CT as a reference standard.

  6. Septal repair implants: evaluation of magnetic resonance imaging safety at 3 T.

    PubMed

    Shellock, Frank G; Valencerina, Samuel

    2005-12-01

    Specialized implants are used for transcatheter closure of septal defects, including atrial and ventricular septal defects, and patent foramen ovale. These metallic devices may pose a risk to patients undergoing magnetic resonance imaging (MRI) procedures especially if performed at 3 T. Therefore, this investigation evaluated MRI safety at 3 T for septal repair implants (CardioSEAL Septal Repair Implant and STARFlex Septal Repair Implant, NMT Medical, Boston, MA, USA) by characterizing magnetic field interactions, heating and artifacts. These implants exhibited minor magnetic field interactions; heating was not excessive (+0.5 degrees C); and artifacts will only create a problem if the area of interest is in the same area as or near these devices. Thus, the findings indicated that it would be safe for a patient with these implants to undergo MRI at 3 T or lower. Importantly, because of the minor magnetic field interactions, MRI may be performed immediately after implantation.

  7. Usefulness of contrast-enhanced magnetic resonance imaging for evaluating solitary pulmonary nodules

    PubMed Central

    2008-01-01

    Abstract Evaluation of solitary pulmonary nodules (SPNs) poses a challenge to radiologists. Chest computed tomography (CT) is considered the standard technique for assessing morphologic findings and intrathoracic spread of an SPN. Although the clinical role of magnetic resonance imaging (MRI) for SPNs remains limited, considerable experience has been gained with MRI of thoracic diseases. Dynamic MRI and dynamic CT are useful for differentiating between malignant and benign SPNs (especially tuberculomas and hamartomas). Furthermore, dynamic MRI is useful for assessing tumor vascularity, interstitium, and vascular endothelial growth factor expression, and for predicting survival outcome among patients with peripheral pulmonary carcinoma. These advantages make dynamic MRI a promising method and a potential biomarker for characterizing tumor response to anti-angiogenic treatment as well as for predicting survival outcomes after treatment. PMID:18331971

  8. Hepatic hemangiomas: evaluation by magnetic resonance imaging and technetium-99m red blood cell scintigraphy

    SciTech Connect

    Brown, R.K.; Gomes, A.; King, W.; Pusey, E.; Lois, J.; Goldstein, L.; Busuttil, R.W.; Hawkins, R.A.

    1987-11-01

    A study was performed to evaluate and compare the sensitivity of magnetic resonance imaging (MRI) and radionuclide blood-pool scanning in the detection of hepatic hemangiomas. All patients had known hemangiomas which were first detected on either ultrasound or computed tomography. Sixteen patients with a total of 23 lesions were investigated. Eleven patients had both MRI and blood-pool scans performed. In the group studied by both modalities, 18 lesions were detected ranging in size from 1 to 11 cm. All lesions were detected by both techniques. However, two of the 18 lesions had an atypical appearance on MRI. Our experience to date indicates that the anatomic location and specific diagnosis of hemangiomas can be made with a high degree of certainty when both MRI and blood-pool scanning techniques are utilized.

  9. Magnetic resonance imaging in the evaluation of clinical treatment of otospongiosis: a pilot study.

    PubMed

    de Oliveira Vicente, Andy; Chandrasekhar, Sujana S; Yamashita, Helio K; Cruz, Oswaldo Laercio M; Barros, Flavia A; Penido, Norma O

    2015-06-01

    To evaluate the applicability of magnetic resonance imaging (MRI) as a method for monitoring the activity of otospongiotic lesions before and after clinical treatment. Prospective, randomized, controlled, double-blind study. One single tertiary care institution in a large, cosmopolitan city. Twenty-six patients (n = 42 ears) with clinical, audiometric, and tomographic diagnosis of otosclerosis were enrolled. If computed tomography (CT) demonstrated active lesions, these patients underwent MRI to detect otospongiotic foci, seen as areas of gadolinium enhancement. Patients were divided into 3 groups and received treatment with placebo, sodium alendronate, or sodium fluoride for 6 months. After this period, clinical and audiometric evaluations and a second MRI were performed. Each MRI was evaluated by both a neuroradiologist and an otolaryngologist in a subjective (visual) and objective (using specific eFilm Workstation software) manner. Otospongiosis was most predominantly identified in the region anterior to the oval window, and this site was reliable for comparing pre- and posttreatment scans. The patients in the alendronate and sodium fluoride groups had MRI findings that suggested a decrease in activity of otospongiotic lesions, more relevant in the alendronate group. These findings were statistically significant for both subjective and objective MRI evaluations. MRI shows higher sensitivity than clinical or audiometric assessment for detecting reduction in activity of otospongiosis. The objective MRI evaluation based on software analysis was the most accurate method of monitoring clinical treatment response in otospongiosis. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  10. Evaluation of multiatlas label fusion for in vivo magnetic resonance imaging orbital segmentation

    PubMed Central

    Panda, Swetasudha; Asman, Andrew J.; Khare, Shweta P.; Thompson, Lindsey; Mawn, Louise A.; Smith, Seth A.; Landman, Bennett A.

    2014-01-01

    Abstract. Multiatlas methods have been successful for brain segmentation, but their application to smaller anatomies remains relatively unexplored. We evaluate seven statistical and voting-based label fusion algorithms (and six additional variants) to segment the optic nerves, eye globes, and chiasm. For nonlocal simultaneous truth and performance level estimation (STAPLE), we evaluate different intensity similarity measures (including mean square difference, locally normalized cross-correlation, and a hybrid approach). Each algorithm is evaluated in terms of the Dice overlap and symmetric surface distance metrics. Finally, we evaluate refinement of label fusion results using a learning-based correction method for consistent bias correction and Markov random field regularization. The multiatlas labeling pipelines were evaluated on a cohort of 35 subjects including both healthy controls and patients. Across all three structures, nonlocal spatial STAPLE (NLSS) with a mixed weighting type provided the most consistent results; for the optic nerve NLSS resulted in a median Dice similarity coefficient of 0.81, mean surface distance of 0.41 mm, and Hausdorff distance 2.18 mm for the optic nerves. Joint label fusion resulted in slightly superior median performance for the optic nerves (0.82, 0.39 mm, and 2.15 mm), but slightly worse on the globes. The fully automated multiatlas labeling approach provides robust segmentations of orbital structures on magnetic resonance imaging even in patients for whom significant atrophy (optic nerve head drusen) or inflammation (multiple sclerosis) is present. PMID:25558466

  11. Diffusion-Weighted Magnetic Resonance Imaging in Evaluation of Gastric Cancer

    PubMed Central

    Kantarci, Mecit; Yuce, Ihsan; Yalcin, Ahmet; Yildirgan, M. Ilhan; Cayir, Kerim; Eren, Suat; Atamanalp, S. Selcuk

    2010-01-01

    Objective: To investigate the role of diffusion-weighted magnetic resonance imaging (DW-MRI) in the diagnosis of gastric tumors and discuss the diagnostic importance and potential use of apparent diffusion coefficient (ADC) measurements. Materials and Methods: Beginning in March 2009, DW-MRI was added to the routine abdominal and pelvic MR examination for all patients imaged at our institution. A total of 21 patients (12 men and 9 women; mean age 55±6.3SD, range: 39–74 years) with known gastric malignancy were referred to our MR unit. All MRI examinations were performed using a 1.5-T MRI scanner (Magnetom Avanto, Siemens Healthcare). The evaluation of the DW-MRI examinations was made by radiologists’ consensus. Changes in the signal intensity of the lesions were determined by their appearance in images at b=50, 400, and 800 s/mm2 and in ADC maps. Results were compared with histopathological findings. Results: All of the gastric tumors in this study showed high signal intensity in DW-MRI and low signal intensity in ADC maps. Mean ADC values for gastric tumor and normal gastric wall were 0.892±0.23 SD mm2/s and 1.453±0.35 SD mm2/s respectively. The mean ADC values of gastric tumors were significantly lower than that of the normal gastric wall. Conclusion: DW-MRI and ADC values together can successfully differentiate gastric tumors from normal gastric wall. PMID:25610124

  12. Evaluation of aortic stenosis by cardiovascular magnetic resonance imaging: comparison with established routine clinical techniques

    PubMed Central

    Kupfahl, C; Honold, M; Meinhardt, G; Vogelsberg, H; Wagner, A; Mahrholdt, H; Sechtem, U

    2004-01-01

    Objective: To evaluate whether direct planimetry of aortic valve area (AVA) by cardiac magnetic resonance (CMR) imaging is a reliable tool for determining the severity of aortic stenosis compared with transthoracic echocardiography (TTE), transoesophageal echocardiography (TOE), and cardiac catheterisation. Methods: 44 symptomatic patients with severe aortic stenosis were studied. By cardiac catheterisation AVA was calculated by the Gorlin equation. AVA was measured with CMR from steady state free precession (true fast imaging with steady state precession) by planimetry. AVA was also determined from TOE images by planimetry and from TTE images by the continuity equation. Results: Bland-Altman analysis evaluating intraobserver and interobserver variability showed a very small bias for both (−0.016 and 0.019, respectively; n  =  20). Bias and limits of agreement between CMR and TTE were 0.05 (−0.35, 0.44) cm2 (n  =  37), between CMR and TOE 0.02 (−0.39, 0.42) cm2 (n  =  32), and between CMR and cardiac catheterisation 0.09 (−0.30, 0.47) cm2 (n  =  36). The sensitivity and specificity of CMR to detect AVA ⩽ 0.80 cm2 measured by cardiac catheterisation was 78% and 89%, of TOE 70% and 70%, and of TTE 74% and 67%, respectively. Conclusion: CMR planimetry is highly reliable and reproducible. Further, CMR planimetry had the best sensitivity and specificity of all non-invasive methods for detecting severe aortic stenosis in comparison with cardiac catheterisation. Therefore, CMR planimetry of AVA with steady state free precession is a new powerful diagnostic tool, particularly for patients with uncertain or discrepant findings by other modalities. PMID:15253962

  13. Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in Dementias

    PubMed Central

    Hsu, Yuan-Yu; Du, An-Tao; Schuff, Norbert; Weiner, Michael W.

    2007-01-01

    This article reviews recent studies of magnetic resonance imaging and magnetic resonance spectroscopy in dementia, including Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, idiopathic Parkinson's disease, Huntington's disease, and vascular dementia. Magnetic resonance imaging and magnetic resonance spectroscopy can detect structural alteration and biochemical abnormalities in the brain of demented subjects and may help in the differential diagnosis and early detection of affected individuals, monitoring disease progression, and evaluation of therapeutic effect. PMID:11563438

  14. Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  15. Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  16. Magnetic resonance imaging

    SciTech Connect

    Stark, D.D.; Bradley, W.G. Jr.

    1988-01-01

    The authors present a review of magnetic resonance imaging. Many topics are explored from instrumentation, spectroscopy, blood flow and sodium imaging to detailed clinical applications such as the differential diagnosis of multiple sclerosis or adrenal adenoma. The emphasis throughout is on descriptions of normal multiplanar anatomy and pathology as displayed by MRI.

  17. Magnetic resonance imaging and ultrasound evaluation after breast autologous fat grafting combined with platelet-rich plasma.

    PubMed

    Fiaschetti, Valeria; Pistolese, Chiara A; Fornari, Maria; Liberto, Valeria; Cama, Valentina; Gentile, Pietro; Floris, Micol; Floris, Roberto; Cervelli, Valerio; Simonetti, Giovanni

    2013-10-01

    Breast lipofilling is a fairly simple and safe procedure if it is performed by experienced surgeons. The authors evaluated the radiologic findings from 24 breasts (15 women) subjected to a lipofilling procedure (two sessions) for corrective surgery or cosmetic reasons. Mammography, ultrasound, and magnetic resonance imaging were performed before the first lipofilling session (T0) and 12 months after the last session (T12); ultrasound and magnetic resonance imaging were used 3 months after the first session (Ti) and 3 and 6 months after the last session (T3 and T6). Volumetric evaluations were also made through three-dimensional magnetic resonance imaging reconstruction. Ultrasound showed oily cysts in 66.67 percent of the breasts at Ti, 70.83 percent at T3, 62.5 percent at T6, and 45.83 percent at T12, whereas magnetic resonance imaging detected oily cysts in 8.33 percent at Ti and T3 and T6 months and 4.17 percent at T12. At Ti, T3, and T6, the cytosteatonecrotic areas identified on both ultrasound and magnetic resonance imaging were unchanged (8.33 percent), whereas at T12 those cytosteatonecrotic areas were increased on ultrasound (12.5 percent) and even more on the magnetic resonance imaging scans (16.67 percent). The average resorption percentage of injected volume was 15.36 percent at T6 months and 28.23 percent at T12 months. Postlipofilling breast changes can be distinguished from malignant alterations by experienced radiologists and need not interfere with early cancer diagnosis if patients are checked regularly. Moreover, magnetic resonance imaging is very useful for breast volume assessments and for detecting possible changes during longitudinal study. Therapeutic, IV.

  18. Is the subscapularis normal after the open Latarjet procedure? An isokinetic and magnetic resonance imaging evaluation.

    PubMed

    Caubère, Alexandre; Lami, Damien; Boileau, Pascal; Parratte, Sébastien; Ollivier, Matthieu; Argenson, Jean-Noël

    2017-10-01

    The Latarjet procedure is considered to be a violation of the subscapularis muscle. This study evaluated the postoperative status of the subscapularis through isokinetic and magnetic resonance imaging analysis after splitting. We hypothesized that compared with a healthy contralateral shoulder, there would be satisfactory recovery of subscapularis strength at the cost of some fatigability and some mild fatty infiltration. This was a case-control retrospective study of patients who underwent a Latarjet procedure between January 2013 and January 2015. A total of 20 patients were reviewed at 1 year postoperatively. With the patient seated, strength testing of both shoulders was done (concentric, eccentric, and fatigability) with a dynamometer. Trophicity and fatty infiltration were analyzed by magnetic resonance imaging. Strength of the internal rotators (IRs) and external rotators (ERs) of the injured shoulder was significantly lower compared with the healthy shoulder in concentric testing at 180°/s and 60°/s (13% for IR and 20% for E, P < .05) and in eccentric testing at 60°/s (19% for IR and 16% for ER, P < .05). A peak torque ratio (ER/IR) of the operated-on shoulder was maintained. The difference in muscular endurance was significant (P < .001). There was no muscle atrophy and minimal or no fatty infiltration of the subscapularis in any patient. At 1 year after the open Latarjet procedure, isokinetic testing showed a combined strength deficit in both internal and external rotation with a conserved muscle balance. Although no significant subscapularis fatty infiltration or atrophy was noted, there was a significant deficit in endurance compared with the healthy shoulder. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  19. Magnetic resonance imaging diffusion tensor tractography: evaluation of anatomic accuracy of different fiber tracking software packages.

    PubMed

    Feigl, Guenther C; Hiergeist, Wolfgang; Fellner, Claudia; Schebesch, Karl-Michael M; Doenitz, Christian; Finkenzeller, Thomas; Brawanski, Alexander; Schlaier, Juergen

    2014-01-01

    Diffusion tensor imaging (DTI)-based tractography has become an integral part of preoperative diagnostic imaging in many neurosurgical centers, and other nonsurgical specialties depend increasingly on DTI tractography as a diagnostic tool. The aim of this study was to analyze the anatomic accuracy of visualized white matter fiber pathways using different, readily available DTI tractography software programs. Magnetic resonance imaging scans of the head of 20 healthy volunteers were acquired using a Siemens Symphony TIM 1.5T scanner and a 12-channel head array coil. The standard settings of the scans in this study were 12 diffusion directions and 5-mm slices. The fornices were chosen as an anatomic structure for the comparative fiber tracking. Identical data sets were loaded into nine different fiber tracking packages that used different algorithms. The nine software packages and algorithms used were NeuroQLab (modified tensor deflection [TEND] algorithm), Sörensen DTI task card (modified streamline tracking technique algorithm), Siemens DTI module (modified fourth-order Runge-Kutta algorithm), six different software packages from Trackvis (interpolated streamline algorithm, modified FACT algorithm, second-order Runge-Kutta algorithm, Q-ball [FACT algorithm], tensorline algorithm, Q-ball [second-order Runge-Kutta algorithm]), DTI Query (modified streamline tracking technique algorithm), Medinria (modified TEND algorithm), Brainvoyager (modified TEND algorithm), DTI Studio modified FACT algorithm, and the BrainLab DTI module based on the modified Runge-Kutta algorithm. Three examiners (a neuroradiologist, a magnetic resonance imaging physicist, and a neurosurgeon) served as examiners. They were double-blinded with respect to the test subject and the fiber tracking software used in the presented images. Each examiner evaluated 301 images. The examiners were instructed to evaluate screenshots from the different programs based on two main criteria: (i) anatomic

  20. Assessing agreement between preclinical magnetic resonance imaging and histology: An evaluation of their image qualities and quantitative results.

    PubMed

    Elschner, Cindy; Korn, Paula; Hauptstock, Maria; Schulz, Matthias C; Range, Ursula; Jünger, Diana; Scheler, Ulrich

    2017-01-01

    One consequence of demographic change is the increasing demand for biocompatible materials for use in implants and prostheses. This is accompanied by a growing number of experimental animals because the interactions between new biomaterials and its host tissue have to be investigated. To evaluate novel materials and engineered tissues the use of non-destructive imaging modalities have been identified as a strategic priority. This provides the opportunity for studying interactions repeatedly with individual animals, along with the advantages of reduced biological variability and decreased number of laboratory animals. However, histological techniques are still the golden standard in preclinical biomaterial research. The present article demonstrates a detailed method comparison between histology and magnetic resonance imaging. This includes the presentation of their image qualities as well as the detailed statistical analysis for assessing agreement between quantitative measures. Exemplarily, the bony ingrowth of tissue engineered bone substitutes for treatment of a cleft-like maxillary bone defect has been evaluated. By using a graphical concordance analysis the mean difference between MRI results and histomorphometrical measures has been examined. The analysis revealed a slightly but significant bias in the case of the bone volume [Formula: see text] and a clearly significant deviation for the remaining defect width [Formula: see text] But the study although showed a considerable effect of the analyzed section position to the quantitative result. It could be proven, that the bias of the data sets was less originated due to the imaging modalities, but mainly on the evaluation of different slice positions. The article demonstrated that method comparisons not always need the use of an independent animal study, additionally.

  1. Preoperative Magnetic Resonance Imaging Evaluation in Patients with Adolescent Idiopathic Scoliosis

    PubMed Central

    Lee, Choon Sung; Kim, Nam Heun; Noh, Hyun Min; Lee, Mi Young; Yoon, So Jung; Lee, Dong-Ho

    2017-01-01

    Study Design Retrospective case series. Purpose The purpose of this study was to examine the incidence of neural axis abnormalities and the relevant risk factors in patients with adolescent idiopathic scoliosis (AIS). Overview of Literature The use of preoperative magnetic resonance imaging (MRI) to assess the whole spine in patients with idiopathic scoliosis is controversial, and indications for such MRI evaluations have not been definitively established. However, we routinely use whole-spine MRI in patients with scoliosis who are scheduled to undergo surgical correction. Methods A total of 378 consecutive patients with presumed AIS who were admitted for spinal surgery were examined for neural axis abnormalities using MRI. To differentiate patients with normal and abnormal MRI findings, the following clinical parameters were evaluated: age, sex, menarcheal status, rotation angle (using a scoliometer), coronal balance, shoulder height difference, and low back pain. We radiographically evaluated curve type, thoracic or thoracolumbar curve direction, curve magnitude and flexibility, apical vertebral rotation, curve length, coronal balance, sagittal balance, shoulder height difference, thoracic kyphosis, and the Risser sign. Results Neural axis abnormalities were detected in 24 patients (6.3%). Abnormal MRI findings were significantly more common in males than in females and were associated with increased thoracic kyphosis. However, there were no significant differences in terms of the other measured parameters. Conclusions Among the patients with presumed AIS who received preoperative whole-spine MRI, 6.3% had neural axis abnormalities. Males and patients with increased thoracic kyphosis were at a higher risk. PMID:28243367

  2. Evaluation of an Automated Analysis Tool for Prostate Cancer Prediction Using Multiparametric Magnetic Resonance Imaging

    PubMed Central

    Roethke, Matthias C.; Kuru, Timur H.; Mueller-Wolf, Maya B.; Agterhuis, Erik; Edler, Christopher; Hohenfellner, Markus; Schlemmer, Heinz-Peter; Hadaschik, Boris A.

    2016-01-01

    Objective To evaluate the diagnostic performance of an automated analysis tool for the assessment of prostate cancer based on multiparametric magnetic resonance imaging (mpMRI) of the prostate. Methods A fully automated analysis tool was used for a retrospective analysis of mpMRI sets (T2-weighted, T1-weighted dynamic contrast-enhanced, and diffusion-weighted sequences). The software provided a malignancy prediction value for each image pixel, defined as Malignancy Attention Index (MAI) that can be depicted as a colour map overlay on the original images. The malignancy maps were compared to histopathology derived from a combination of MRI-targeted and systematic transperineal MRI/TRUS-fusion biopsies. Results In total, mpMRI data of 45 patients were evaluated. With a sensitivity of 85.7% (with 95% CI of 65.4–95.0), a specificity of 87.5% (with 95% CI of 69.0–95.7) and a diagnostic accuracy of 86.7% (with 95% CI of 73.8–93.8) for detection of prostate cancer, the automated analysis results corresponded well with the reported diagnostic accuracies by human readers based on the PI-RADS system in the current literature. Conclusion The study revealed comparable diagnostic accuracies for the detection of prostate cancer of a user-independent MAI-based automated analysis tool and PI-RADS-scoring-based human reader analysis of mpMRI. Thus, the analysis tool could serve as a detection support system for less experienced readers. The results of the study also suggest the potential of MAI-based analysis for advanced lesion assessments, such as cancer extent and staging prediction. PMID:27454770

  3. Evaluation of the Prostate Bed for Local Recurrence After Radical Prostatectomy Using Endorectal Magnetic Resonance Imaging

    SciTech Connect

    Liauw, Stanley L.; Pitroda, Sean P.; Eggener, Scott E.; Stadler, Walter M.; Pelizzari, Charles A.; Vannier, Michael W.; Oto, Aytek

    2013-02-01

    Purpose: To summarize the results of a 4-year period in which endorectal magnetic resonance imaging (MRI) was considered for all men referred for salvage radiation therapy (RT) at a single academic center; to describe the incidence and location of locally recurrent disease in a contemporary cohort of men with biochemical failure after radical prostatectomy (RP), and to identify prognostic variables associated with MRI findings in order to define which patients may have the highest yield of the study. Methods and Materials: Between 2007 and 2011, 88 men without clinically palpable disease underwent eMRI for detectable prostate-specific antigen (PSA) after RP. The median interval between RP and eMRI was 32 months (interquartile range, 14-57 months), and the median PSA level was 0.30 ng/mL (interquartile range, 0.19-0.72 ng/mL). Magnetic resonance imaging scans consisting of T2-weighted, diffusion-weighted, and dynamic contrast-enhanced imaging were evaluated for features consistent with local recurrence. The prostate bed was scored from 0-4, whereby 0 was definitely normal, 1 probably normal, 2 indeterminate, 3 probably abnormal, and 4 definitely abnormal. Local recurrence was defined as having a score of 3-4. Results: Local recurrence was identified in 21 men (24%). Abnormalities were best appreciated on T2-weighted axial images (90%) as focal hypointense lesions. Recurrence locations were perianastomotic (67%) or retrovesical (33%). The only risk factor associated with local recurrence was PSA; recurrence was seen in 37% of men with PSA >0.3 ng/mL vs 13% if PSA {<=}0.3 ng/mL (P<.01). The median volume of recurrence was 0.26 cm{sup 3} and was directly associated with PSA (r=0.5, P=.02). The correlation between MRI-based tumor volume and PSA was even stronger in men with positive margins (r=0.8, P<.01). Conclusions: Endorectal MRI can define areas of local recurrence after RP in a minority of men without clinical evidence of disease, with yield related to PSA

  4. Paraganglioma of the heart. The value of magnetic resonance imaging in the preoperative evaluation.

    PubMed

    Conti, V R; Saydjari, R; Amparo, E G

    1986-10-01

    Although the 131I-metaiodobenzylguanidine scan has proven reliable in identifying mediastinal paragangliomas, further localization has usually required dynamic computerized tomographic scanning which requires rapid bolus injection of contrast material. In the case presented herein, magnetic resonance imaging provided accurate preoperative localization and added important anatomic detail that was not appreciated with dynamic computerized tomograms or with other studies. Magnetic resonance imaging can accurately localize cardiac paragangliomas without injection of contrast material and may provide more detailed information for better guidance for surgical excision.

  5. Magnetic Resonance Imaging (MRI) Evaluation for Anterior Disc Displacement of the Temporomandibular Joint

    PubMed Central

    Yang, Zhongjun; Wang, Mingguo; Ma, Yingwei; Lai, Qingguo; Tong, Dongdong; Zhang, Fenghe; Dong, Lili

    2017-01-01

    Background Magnetic resonance imaging (MRI) is the criterion standard imaging technique for visualization of the temporomandibular joint (TMJ) region, and is currently considered the optimum modality for comprehensive evaluation in patients with temporomandibular joint disorder (TMD). This study was aimed at finding the value of MRI in pre-clinical diagnosis of TMJ disc displacement. Material/Methods Patients primarily diagnosed as having anterior disc displacement by clinical symptoms and X-ray were selected in the present study. MRI was used to evaluate surrounding anatomical structures and position, as well as morphological and signal intensity change between patients and normal controls. Results Posterior band position was significantly different between the patient group and control group. At the maximum opened-mouth position, the location of disc intermediate zone returned to normal. At closed-mouth position, the thickness of anterior and middle, but not posterior, band increased. The motion range of the condyle in the anterior disc displacement without reduction (ADDWR) patient group was significantly less than the value in the anterior disc displacement with reduction (ADDR) patient group and the control group. Whether at closed-mouth position or maximum opened-mouth position, the exudate volume in the patient group was greater than in the normal group. Conclusions MRI can be successfully used to evaluate multiple morphological changes at different mouth positions of normal volunteers and patients. The disc-condyle relationship can serve as an important indicator in assessing anterior disc displacement, and can be used to distinguish disc displacement with or without reduction. PMID:28176754

  6. Magnetic Resonance Imaging (MRI) Evaluation for Anterior Disc Displacement of the Temporomandibular Joint.

    PubMed

    Yang, Zhongjun; Wang, Mingguo; Ma, Yingwei; Lai, Qingguo; Tong, Dongdong; Zhang, Fenghe; Dong, Lili

    2017-02-08

    BACKGROUND Magnetic resonance imaging (MRI) is the criterion standard imaging technique for visualization of the temporomandibular joint (TMJ) region, and is currently considered the optimum modality for comprehensive evaluation in patients with temporomandibular joint disorder (TMD). This study was aimed at finding the value of MRI in pre-clinical diagnosis of TMJ disc displacement. MATERIAL AND METHODS Patients primarily diagnosed as having anterior disc displacement by clinical symptoms and X-ray were selected in the present study. MRI was used to evaluate surrounding anatomical structures and position, as well as morphological and signal intensity change between patients and normal controls. RESULTS Posterior band position was significantly different between the patient group and control group. At the maximum opened-mouth position, the location of disc intermediate zone returned to normal. At closed-mouth position, the thickness of anterior and middle, but not posterior, band increased. The motion range of the condyle in the anterior disc displacement without reduction (ADDWR) patient group was significantly less than the value in the anterior disc displacement with reduction (ADDR) patient group and the control group. Whether at closed-mouth position or maximum opened-mouth position, the exudate volume in the patient group was greater than in the normal group. CONCLUSIONS MRI can be successfully used to evaluate multiple morphological changes at different mouth positions of normal volunteers and patients. The disc-condyle relationship can serve as an important indicator in assessing anterior disc displacement, and can be used to distinguish disc displacement with or without reduction.

  7. Vulnerable atherosclerotic carotid plaque evaluation by ultrasound, computed tomography angiography, and magnetic resonance imaging: an overview.

    PubMed

    Naim, Cyrille; Douziech, Maxime; Therasse, Eric; Robillard, Pierre; Giroux, Marie-France; Arsenault, Frederic; Cloutier, Guy; Soulez, Gilles

    2014-08-01

    Ischemic syndromes associated with carotid atherosclerotic disease are often related to plaque rupture. The benefit of endarterectomy for high-grade carotid stenosis in symptomatic patients has been established. However, in asymptomatic patients, the benefit of endarterectomy remains equivocal. Current research seeks to risk stratify asymptomatic patients by characterizing vulnerable, rupture-prone atherosclerotic plaques. Plaque composition, biology, and biomechanics are studied by noninvasive imaging techniques such as magnetic resonance imaging, computed tomography, ultrasound, and ultrasound elastography. These techniques are at a developmental stage and have yet to be used in clinical practice. This review will describe noninvasive techniques in ultrasound, magnetic resonance imaging, and computed tomography imaging modalities used to characterize atherosclerotic plaque, and will discuss their potential clinical applications, benefits, and drawbacks. Copyright © 2014 Canadian Association of Radiologists. Published by Elsevier Inc. All rights reserved.

  8. Magnetic resonance imaging used for the evaluation of water presence in wood plastic composite boards exposed to exterior conditions

    Treesearch

    Marek Gnatowski; Rebecca Ibach; Mathew Leung; Grace Sun

    2014-01-01

    Two wood plastic composite (WPC) boards, one experimental and one commercial, were exposed to exterior conditions and evaluated non-destructively using a clinical magnetic resonance imaging (MRI) unit for moisture content (MC) and distribution. The experimental board was exposed in Vancouver, British Columbia, for more than 8 years, and the commercial board was exposed...

  9. Carotid Plaque Evaluation Using Gemstone Spectral Imaging: Comparison with Magnetic Resonance Angiography.

    PubMed

    Shinohara, Yuki; Sakamoto, Makoto; Kuya, Keita; Kishimoto, Junichi; Yamashita, Eijiro; Fujii, Shinya; Kurosaki, Masamichi; Ogawa, Toshihide

    2017-07-01

    The present study compared the applicability of computed tomography carotid plaque imaging using effective Z maps with gemstone spectral imaging (GSI) to that of magnetic resonance plaque imaging using 3-dimensional time-of-flight magnetic resonance angiography. Stenosis was assessed in 18 carotid arteries of 14 patients, and the effective Z values of noncalcified carotid plaques were compared with the signal intensities of magnetic resonance angiography. It was found that the effective Z value of noncalcified carotid plaques was significantly lower for a group with high signal intensity than for a group with low signal intensity on magnetic resonance angiography (P <.001). The area under the receiver operating characteristic curve of effective Z values was .975, and the presumed cutoff effective Z value required to discriminate low and high intensity plaques on magnetic resonance angiography was 7.83. The effective Z value generated by GSI is a useful parameter to detect vulnerable carotid plaque materials. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  10. Evaluation of the reproducibility in the interpretation of magnetic resonance images of the temporomandibular joint

    PubMed Central

    Butzke, K W; Batista Chaves, K D; Dias da Silveira, H E; Dias da Silveira, H L

    2010-01-01

    Objectives The aim was to determine the intra- and interexaminer reproducibility in the interpretation of MRI of the temporomandibular joint among independent observers, with respect to six specific articular characteristics, and to discover which of these had greater and lesser agreement. Methods 30 magnetic resonance examinations of temporomandibular joints of adults were independently interpreted by 9 experienced and trained observers at 2 different times. Observers were divided into three groups according to their specialties: surgeon dentists specialized in temporomandibular dysfunction and orofacial pain, surgeon dentists specialized in radiology and medical doctors specialized in radiology. The reproducibility analysis was carried out using Cohen's kappa coefficient. Results The interexaminer reproducibility ranged from slight to fair. The intraexaminer reproducibility ranged from slight to no agreement. In the interexaminer evaluation, anterior disc displacement without reduction presented greater agreement, whereas change in condylar head shape showed the poorest agreement. In the intraexaminer evaluation, anterior disc displacement without reduction presented slight agreement, whereas, for the other characteristics, no agreement was observed. Conclusion Examiners do not demonstrate reproducibility in the interpretation of MRI of temporomandibular joints. Therefore, more efforts are necessary with respect to understanding the changes that may be detected in these images in terms of diagnosis and appropriate treatment approaches. PMID:20203277

  11. Magnetic resonance imaging versus computed tomography in the evaluation of soft tissue tumors of the extremities

    SciTech Connect

    Chang, A.E.; Matory, Y.L.; Dwyer, A.J.; Hill, S.C.; Girton, M.E.; Steinberg, S.M.; Knop, R.H.; Frank, J.A.; Hyams, D.; Doppman, J.L.

    1987-04-01

    Twenty patients with extremity soft tissue tumors were prospectively evaluated with magnetic resonance imaging (MRI) and computed tomography (CT) scans with subsequent anatomic correlation of surgical findings. MRI and CT had a similar percentage of accuracy in assessing tumor relationship with major neurovascular (80% and 70%, respectively) and skeletal (80% and 75%, respectively) structures. MRI was significantly better than CT in displaying contrast between tumor and muscle when using the T2 weighted spin echo (SE) (p2 less than 0.002) and inversion recovery (IR) (p2 less than 0.005) pulse sequences. MRI and CT were comparable in demonstrating contrast between tumor and fat. The contrast between tumor and vessel was better displayed by MRI compared with CT when using the T1 weighted SE (p2 less than 0.001) and T2 weighted SE (p2 less than 0.001) pulse sequences. T1 and T2 values were measured on fresh tumor and normal tissue samples and were used to predict relative contrast on different MRI pulse sequences using isosignal contour plots. MRI appears to offer several advantages over CT in the evaluation of extremity soft tissue tumors.

  12. Can we evaluate cranial aneurysms on conventional brain magnetic resonance imaging?

    PubMed

    Caliskan, Emine; Pekcevik, Yeliz; Kaya, Adnan

    2016-01-01

    To evaluate the contribution of conventional brain magnetic resonance imaging (MRI) for the determination of intracranial aneurysms. Brain MRI and computed tomography angiography (CTA) of 45 patients (29 women and 16 men; age range, 32-80 years) with aneurysm were analyzed. A comparison was made between brain MRI and CTA based on size and presence of aneurysm. The comparisons between MRI and CTA were investigated through Bland-Altman graphics, receiver operating characteristic curve, and Kappa statistics. Fifty-seven aneurysms were evaluated. Forty-five percent of 57 aneurysms on CTA were detected on conventional brain MRI. A significant correlation was found between CTA and brain MRI in the diagnosis of aneurysm (P < 0.05). In an analysis of the size measurement, a significant correlation was observed between CTA and brain MRI. Seventy-seven percent of aneurysms <4 mm was not detected and the efficiency of MRI in the detection of aneurysms <4 mm was found to be low. Aneurysms can also be appreciated on conventional brain MRI, and vascular structures should be reviewed carefully while analyzing brain MRI.

  13. Evaluation of masticatory activity during unilateral single tooth clenching using muscle functional magnetic resonance imaging.

    PubMed

    Okada, C; Yamaguchi, S; Watanabe, Y; Watanabe, M; Hattori, Y

    2016-08-01

    Masticatory muscle activity during teeth clenching is affected by occlusal pattern. However, few studies have performed simultaneous evaluation of all masticatory activities during teeth clenching under various occlusal conditions. The aim of this study was to use muscle functional magnetic resonance imaging (mfMRI) to evaluate the effects of changes in occlusal point on masticatory activity during single tooth clenching. Changes in mean proton transverse relaxation time (∆T2) as an index of activity in all masticatory muscles during left unilateral clenching at the first molar or first premolar for 1 min were examined in nine healthy volunteers. Bite force was maintained at 40% of the maximum voluntary clenching force. The ∆T2 values of the masseter and lateral pterygoid muscles were analysed separately for superficial and deep layers, and for superior and inferior heads. The ∆T2 values for the ipsilateral deep masseter were significantly lower, and for the superior head of the ipsilateral lateral pterygoid muscles were significantly higher, after left first premolar clenching compared to left first molar clenching. These results quantitatively demonstrate a significant increase in activity of the superior head of the ipsilateral lateral pterygoid muscle and a significant decrease in activity of the ipsilateral deep masseter muscle with forward displacement of the occlusal contact point during unilateral tooth clenching.

  14. Magnetic Resonance Image Evaluation of Temporomandibular Joint Osteophytes: Influence of Clinical Factors and Artrogenics Changes.

    PubMed

    Grossmann, Eduardo; Remedi, Marcelo Pereira; Ferreira, Luciano Ambrosio; Carvalho, Antonio Carlos Pires

    2016-03-01

    This research aims to examine the presence of osteophyte in patients with arthrogenic temporomandibular disorders through magnetic resonance imaging (MRI); to investigate the influence of sex and clinical symptoms in its prevalence; and the position of the osteophytes in the condyle. The study was based on 100 MRI and on reports of patients, which corresponded to the evaluation of 200 joints. Patients of both sexes were aged from 18 to 82 years (average = 49.48) and were subjected to the aforementioned examination from January 2006 to March 2009. The assessment considered the type of disc displacement, the presence of effusion, bone marrow edema, condyle changes, joint noise and pain. The MRI machine used was the GE Signa HDX (General Electric, Milwaukee, WI), with T1 and T2-weighted, 1.5 T magnetic field, sagittal oblique (mouth closed, mouth open) and coronal (mouth closed) imaging, with spherical surface coil and an asymmetric matrix. All images were interpreted by an experienced radiologist. A total of 28% (n = 56) of the temporomandibular joints showed osteophytes on the anterior surface of the mandible. No relationship was found between sex and osteophytes. The authors found a statistically significant difference between osteophytes and disc displacement without reduction (P < 0.001). The presence of osteophytes suggested a possible cause and effect relationship between osteoarthritis and disc displacement without reduction; the osteophyte was always located in the anterior surface of condyle, regardless of the sex variable; no significant difference was found between osteophytes and the main complaints of the patient.

  15. Magnetic resonance imaging and ultrasound evaluation of "healthy" joints in young subjects with severe haemophilia A.

    PubMed

    Di Minno, M N D; Iervolino, S; Soscia, E; Tosetto, A; Coppola, A; Schiavulli, M; Marrone, E; Ruosi, C; Salvatore, M; Di Minno, G

    2013-05-01

    Magnetic resonance imaging (MRI) and ultrasonography (US) are increasingly used in haemophilia A (HA) to detect early joint changes. A total of 40 clinically asymptomatic joints, never involved by bleeding events ["healthy joints" (HJ)], were evaluated by MRI and, in parallel, by US in 20 young subjects with severe HA (22.45 ± 2.72 years old; no history of arthritides, of viral infections or of inhibitors against factor VIII). The same joints were evaluated in 20 matched non-haemophilic (no-HA) subjects (mean age 23.90 ± 2.31 years, P = 0.078 vs. HA subjects). US images were obtained with specific probe positions according to validated procedures. A validated US score and progressive (P-MRI) and additive (A-MRI) MRI scores were employed for data collection and analysis. The US score was higher in HA than in no-HA subjects (3.40 ± 1.72 vs. 0.80 ± 1.10, P < 0.001). Taking into account only moderate/severe alterations, joint effusion was found in 55% of HA and in 5% of no-HA joints (P < 0.001); synovial hypertrophy was found in 20% of HA and in none of the no-HA joints; cartilage erosion was found in 30% of HA and in none of no-HA joints. MRI examinations confirmed these findings and the US score correlated with the A-MRI (r = 0.732, P < 0.001) and with the P-MRI (r = 0.598, P < 0.001) scores. MRI and US data significantly correlated as to effusion (r = 0.819, P = 0.002), synovial hypertrophy (r = 0.633, P = 0.036) and cartilage erosion (r = 0.734, P = 0.010). Despite inherent limitations, joint US examination identified subclinical abnormalities of HJ in young subjects with severe HA.

  16. Cervical external immobilization devices: evaluation of magnetic resonance imaging issues at 3.0 Tesla.

    PubMed

    Diaz, Francis L; Tweardy, Lisa; Shellock, Frank G

    2010-02-15

    Laboratory investigation, ex vivo. Currently, no studies have addressed the magnetic resonance imaging (MRI) issues for cervical external immobilization devices at 3-Tesla. Under certain conditions significant heating may occur, resulting in patient burns. Furthermore, artifacts can be substantial and prevent the diagnostic use of MRI. Therefore, the objective of this investigation was to evaluate MRI issues for 4 different cervical external immobilization devices at 3-Tesla. Excessive heating and substantial artifacts are 2 potential complications associated with performing MRI at 3-Tesla in patients with cervical external immobilization devices. Using ex vivo testing techniques, MRI-related heating and artifacts were evaluated for 4 different cervical devices during MRI at 3-Tesla. Four cervical external immobilization devices (Generation 80, Resolve Ring and Superstructure, Resolve Ring and Jerome Vest/Jerome Superstructure, and the V1 Halo System; Ossur Americas, Aliso Viejo, CA) underwent MRI testing at 3-Tesla. All devices were made from nonmetallic or nonmagnetic materials. Heating was determined using a gelled-saline-filled skull phantom with fluoroptic thermometry probes attached to the skull pins. MRI was performed at 3-Tesla, using a high level of RF energy. Artifacts were assessed at 3-Tesla, using standard cervical imaging techniques. The Generation 80 and V1 Halo devices exhibited substantial temperature rises (11.6 degrees C and 8.5 degrees C, respectively), with "sparking" evident for the Generation 80 during the MRI procedure. Artifacts were problematic for these devices, as well. By comparison, the 2 Resolve Ring-based cervical external immobilization devices showed little or no heating (< or = 0.6 degrees C) and the artifacts were acceptable for diagnostic MRI examinations. The low degree of heating and minor artifacts associated with the Resolve-based cervical external immobilization devices indicated that these products are safe for patients

  17. Preclinical evaluation of implantable cardioverter-defibrillator developed for magnetic resonance imaging use.

    PubMed

    Gold, Michael R; Kanal, Emanuel; Schwitter, Juerg; Sommer, Torsten; Yoon, Hyun; Ellingson, Michael; Landborg, Lynn; Bratten, Tara

    2015-03-01

    Many patients with an implantable cardioverter-defibrillator (ICD) have indications for magnetic resonance imaging (MRI). However, MRI is generally contraindicated in ICD patients because of potential risks from hazardous interactions between the MRI and ICD system. The purpose of this study was to use preclinical computer modeling, animal studies, and bench and scanner testing to demonstrate the safety of an ICD system developed for 1.5-T whole-body MRI. MRI hazards were assessed and mitigated using multiple approaches: design decisions to increase safety and reliability, modeling and simulation to quantify clinical MRI exposure levels, animal studies to quantify the physiologic effects of MRI exposure, and bench testing to evaluate safety margin. Modeling estimated the incidence of a chronic change in pacing capture threshold >0.5 V and 1.0 V to be less than 1 in 160,000 and less than 1 in 1,000,000 cases, respectively. Modeling also estimated the incidence of unintended cardiac stimulation to occur in less than 1 in 1,000,000 cases. Animal studies demonstrated no delay in ventricular fibrillation detection and no reduction in ventricular fibrillation amplitude at clinical MRI exposure levels, even with multiple exposures. Bench and scanner testing demonstrated performance and safety against all other MRI-induced hazards. A preclinical strategy that includes comprehensive computer modeling, animal studies, and bench and scanner testing predicts that an ICD system developed for the magnetic resonance environment is safe and poses very low risks when exposed to 1.5-T normal operating mode whole-body MRI. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  18. Magnetic resonance imaging evaluation of residual tumors in breast cancer after neoadjuvant chemotherapy: surgical implications.

    PubMed

    Zhou, Juan; Li, Gongjie; Sheng, Fugeng; Qiao, Penggang; Zhang, Hongtao; Xing, Xudong

    2016-05-01

    Magnetic resonance imaging (MRI) can be used to guide breast cancer surgery with breast conservation for large tumors with a substantially reduced size after neoadjuvant chemotherapy (NAC). To evaluate the value of dynamic contrast-enhanced MRI (DCE-MRI) for measuring residual tumor size and enhancement patterns following preoperative NAC. Eighty-nine patients with breast cancer underwent breast DCE-MRI; 38 patients (39 lesions) were treated with NAC and examined for residual disease following therapy. Two patients were excluded because surgery had been performed >2 weeks after the final MR examination. Thus, we correlated the DCE-MRI results of 36 patients (37 lesions) with postoperative histopathological findings. Residual disease was confirmed by more enhancement compared to normal glandular tissue at the initial tumor site. Residual tumor size on DCE-MRI was compared with postoperative pathology findings. Tumor enhancement patterns on DCE-MRI were analyzed and correlated with pathological classification. MRI revealed 34 cases of residual tumors, with two false positives and one false negative. Pathological and MR measurements were correlated (r = 0.793). The correlation of mass enhancement size (r = 0.87, n = 14) with pathology and DCE-MRI was higher than for non-mass-like enhancement (NME) (r = 0.735, n = 23). The distribution of pathologic classification was significantly different between different MRI enhancement patterns (P = 0.006). Mass enhancement had higher cellularity than NME. MRI is useful for evaluating residual carcinoma following NAC. Mass enhancement with higher cellularity after NAC can be evaluated more accurately, which is suitable for evaluating lumpectomy. However, other approaches are required for NME, which has lower cellularity. © The Foundation Acta Radiologica 2015.

  19. Gynecologic masses: value of magnetic resonance imaging.

    PubMed

    Hricak, H; Lacey, C; Schriock, E; Fisher, M R; Amparo, E; Dooms, G; Jaffe, R

    1985-09-01

    Forty-two women with gynecologic abnormalities were studied with the use of magnetic resonance imaging. Magnetic resonance imaging correctly assessed the origin of the pelvic mass in all patients. In the evaluation of leiomyoma, magnetic resonance imaging accurately depicted the number, size, and location of the lesion. In the evaluation of endometrial carcinoma, magnetic resonance imaging depicted the location of the lesion, the presence of cervical extension, and the depth of myometrial penetration in the majority of the cases. In the analysis of adnexal cysts, magnetic resonance imaging was sensitive in localizing the lesion and was able to distinguish serous from hemorrhagic fluid. This preliminary report indicates that magnetic resonance imaging may become a valuable imaging modality in the diagnosis of gynecologic abnormalities.

  20. Validation of Supervised Automated Algorithm for Fast Quantitative Evaluation of Organ Motion on Magnetic Resonance Imaging

    SciTech Connect

    Prakash, Varuna; Stainsby, Jeffrey A.; Satkunasingham, Janakan; Craig, Tim; Catton, Charles; Chan, Philip; Dawson, Laura; Hensel, Jennifer; Jaffray, David; Milosevic, Michael; Nichol, Alan; Sussman, Marshall S.; Lockwood, Gina; Menard, Cynthia

    2008-07-15

    Purpose: To validate a correlation coefficient template-matching algorithm applied to the supervised automated quantification of abdominal-pelvic organ motion captured on time-resolved magnetic resonance imaging. Methods and Materials: Magnetic resonance images of 21 patients across four anatomic sites were analyzed. Representative anatomic points of interest were chosen as surrogates for organ motion. The point of interest displacements across each image frame relative to baseline were quantified manually and through the use of a template-matching software tool, termed 'Motiontrack.' Automated and manually acquired displacement measures, as well as the standard deviation of intrafraction motion, were compared for each image frame and for each patient. Results: Discrepancies between the automated and manual displacements of {>=}2 mm were uncommon, ranging in frequency of 0-9.7% (liver and prostate, respectively). The standard deviations of intrafraction motion measured with each method correlated highly (r = 0.99). Considerable interpatient variability in organ motion was demonstrated by a wide range of standard deviations in the liver (1.4-7.5 mm), uterus (1.1-8.4 mm), and prostate gland (0.8-2.7 mm). The automated algorithm performed successfully in all patients but 1 and substantially improved efficiency compared with manual quantification techniques (5 min vs. 60-90 min). Conclusion: Supervised automated quantification of organ motion captured on magnetic resonance imaging using a correlation coefficient template-matching algorithm was efficient, accurate, and may play an important role in off-line adaptive approaches to intrafraction motion management.

  1. Evaluation of Transient Motion During Gadoxetic Acid-Enhanced Multiphasic Liver Magnetic Resonance Imaging Using Free-Breathing Golden-Angle Radial Sparse Parallel Magnetic Resonance Imaging.

    PubMed

    Yoon, Jeong Hee; Lee, Jeong Min; Yu, Mi Hye; Hur, Bo Yun; Grimm, Robert; Block, Kai Tobias; Chandarana, Hersh; Kiefer, Berthold; Son, Yohan

    2017-09-11

    The aims of this study were to observe the pattern of transient motion after gadoxetic acid administration including incidence, onset, and duration, and to evaluate the clinical feasibility of free-breathing gadoxetic acid-enhanced liver magnetic resonance imaging using golden-angle radial sparse parallel (GRASP) imaging with respiratory gating. In this institutional review board-approved prospective study, 59 patients who provided informed consents were analyzed. Free-breathing dynamic T1-weighted images (T1WIs) were obtained using GRASP at 3 T after a standard dose of gadoxetic acid (0.025 mmol/kg) administration at a rate of 1 mL/s, and development of transient motion was monitored, which is defined as a distinctive respiratory frequency alteration of the self-gating MR signals. Early arterial, late arterial, and portal venous phases retrospectively reconstructed with and without respiratory gating and with different temporal resolutions (nongated 13.3-second, gated 13.3-second, gated 6-second T1WI) were evaluated for image quality and motion artifacts. Diagnostic performance in detecting focal liver lesions was compared among the 3 data sets. Transient motion (mean duration, 21.5 ± 13.0 seconds) was observed in 40.0% (23/59) of patients, 73.9% (17/23) of which developed within 15 seconds after gadoxetic acid administration. On late arterial phase, motion artifacts were significantly reduced on gated 13.3-second and 6-second T1WI (3.64 ± 0.34, 3.61 ± 0.36, respectively), compared with nongated 13.3-second T1WI (3.12 ± 0.51, P < 0.0001). Overall, image quality was the highest on gated 13.3-second T1WI (3.76 ± 0.39) followed by gated 6-second and nongated 13.3-second T1WI (3.39 ± 0.55, 2.57 ± 0.57, P < 0.0001). Only gated 6-second T1WI showed significantly higher detection performance than nongated 13.3-second T1WI (figure of merit, 0.69 [0.63-0.76]) vs 0.60 [0.56-0.65], P = 0.004). Transient motion developed in 40% (23/59) of patients shortly after

  2. Magnetic Resonance Imaging to Evaluate Cervical Spinal Cord Injury from Gunshot Wounds from Handguns.

    PubMed

    Slavin, Justin; Beaty, Narlin; Raghavan, Prashant; Sansur, Charles; Aarabi, Bizhan

    2015-12-01

    Patients presenting with gunshot wounds (GSWs) to the neck are difficult to assess because of their injuries are often severe and they are incompletely evaluated by computed tomography (CT) alone. Our institution treats hundreds of patients with GSWs each year and we present our experience using magnetic resonance imaging (MRI) in the evaluation of cervical GSWs. From August 2000 to July 2012, all GSWs to the cervical spine treated at our institution were cataloged. Seventeen patients had 1 or more MRI studies of the cervical spine. Informed consent was obtained before MRI indicating the risks of retained metal fragments in the setting of high magnetic fields. CT scans were obtained before and after MRI to document any possible migration of metal fragments. We documented patients' neurologic examination results before and after MRI and at follow-up. Patients' age range was 18-56 years (mean 29.8 years). Eleven of 17 patients had retained metal fragments seen on CT scan, including 3 patients with fragments within the spinal canal. No patient experienced a decline in neurologic function after MRI. No migration of retained fragments was observed. Fifteen of 17 patients returned for follow-up examinations, with an average follow-up interval of 39.1 weeks (range, 1.3-202.3 weeks; median, 8 weeks). For carefully selected patients, MRI can be an effective tool in assessing GSWs to the neck and it can significantly improve the evaluation and management of this cohort. No patient in our series experienced a complication related to MRI. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Subtypes evaluation of motor dysfunction in Parkinson's disease using neuromelanin-sensitive magnetic resonance imaging.

    PubMed

    Xiang, Yuanyuan; Gong, Tao; Wu, Junwei; Li, Jifeng; Chen, Yan; Wang, Yongxiang; Li, Shan; Cong, Lin; Lin, Youting; Han, Yuxiang; Yin, Ling; Wang, Guangbin; Du, Yifeng

    2017-01-18

    Parkinson's disease (PD) is characterized by the loss of neuromelanin (NM)-containing neurons in the substantia nigra pars compacta (SNc), and it is divided into two motor subtypes: the postural instability gait difficulty (PIGD) and the tremor dominant (TD) subtypes. With NM-sensitive Magnetic Resonance Imaging (NM-MRI), investigators have been able to accurately detect signal attenuation in SNc of PD; however, the difference of NM loss between PIGD and TD subtypes is still unclear. Thus, the aim of this study was to evaluate the differences in NM-MRI between PD motor subtypes. PD patients were classified into PIGD (n=14) and TD groups (n=9); 20 age and sex matched controls were recruited. We compared the signal intensity contrast ratios in medial and lateral regions of the SNc using NM-MRI in PIGD, TD, and controls, respectively. Remarkable signal attenuation was observed in the lateral part of SNc in PD when compared with the controls, and we were able to detect more severe signal attenuation in the medial part of SNc in PIGD patients in comparison with that in the TD group. Also, the medial part of SNc, ipsilateral to the most clinically affected side, showed the highest power to discriminate the PD motor subtypes (AUC, 81%; sensitivity, 71.4%; specificity, 77.8%). Our results indicated a potential diagnostic value of NM-MRI to discriminate the PD motor subtypes, providing new evidence for the neuropathology-based differences between the two subtypes.

  4. Evaluation of expert criteria for preoperative magnetic resonance imaging of newly diagnosed breast cancer.

    PubMed

    Behrendt, Carolyn E; Tumyan, Lusine; Gonser, Laura; Shaw, Sara L; Vora, Lalit; Paz, I Benjamin; Ellenhorn, Joshua D I; Yim, John H

    2014-08-01

    Despite 2 randomized trials reporting no reduction in operations or local recurrence at 1 year, preoperative magnetic resonance imaging (MRI) is increasingly used in diagnostic workup of breast cancer. We evaluated 5 utilization criteria recently proposed by experts. Of women (n = 340) newly diagnosed with unilateral breast cancer who underwent bilateral MRI, most (69.4%) met at least 1 criterion before MRI: mammographic density (44.4%), under consideration for partial breast irradiation (PBI) (19.7%), genetic-familial risk (12.9%), invasive lobular carcinoma (11.8%), and multifocal/multicentric disease (10.6%). MRI detected occult malignant lesion or extension of index lesion in 21.2% of index, 3.3% of contralateral, breasts. No expert criterion was associated with MRI-detected malignant lesion, which associated instead with pre-MRI plan of lumpectomy without PBI (48.2% of subjects): Odds Ratio 3.05, 95% CI 1.57-5.91 (p adjusted for multiple hypothesis testing = 0.007, adjusted for index-vs-contralateral breast and covariates). The expert guidelines were not confirmed by clinical evidence.

  5. Using Magnetic Resonance Imaging to Evaluate Dendritic Cell-Based Vaccination

    PubMed Central

    Ferguson, Peter M.; Slocombe, Angela; Tilley, Richard D.; Hermans, Ian F.

    2013-01-01

    Cancer immunotherapy with antigen-loaded dendritic cell-based vaccines can induce clinical responses in some patients, but further optimization is required to unlock the full potential of this strategy in the clinic. Optimization is dependent on being able to monitor the cellular events that take place once the dendritic cells have been injected in vivo, and to establish whether antigen-specific immune responses to the tumour have been induced. Here we describe the use of magnetic resonance imaging (MRI) as a simple, non-invasive approach to evaluate vaccine success. By loading the dendritic cells with highly magnetic iron nanoparticles it is possible to assess whether the injected cells drain to the lymph nodes. It is also possible to establish whether an antigen-specific response is initiated by assessing migration of successive rounds of antigen-loaded dendritic cells; in the face of a successfully primed cytotoxic response, the bulk of antigen-loaded cells are eradicated on-route to the node, whereas cells without antigen can reach the node unchecked. It is also possible to verify the induction of a vaccine-induced response by simply monitoring increases in draining lymph node size as a consequence of vaccine-induced lymphocyte trapping, which is an antigen-specific response that becomes more pronounced with repeated vaccination. Overall, these MRI techniques can provide useful early feedback on vaccination strategies, and could also be used in decision making to select responders from non-responders early in therapy. PMID:23734246

  6. Magnetic resonance imaging evaluation of meniscoid superior labrum: normal variant or superior labral tear*

    PubMed Central

    Simão, Marcelo Novelino; Vinson, Emily N.; Spritzer, Charles E.

    2016-01-01

    Objective The objective of this study was to determine the incidence of a "meniscoid" superior labrum. Materials and Methods This was a retrospective analysis of 582 magnetic resonance imaging examinations of shoulders. Of those 582 examinations, 110 were excluded, for a variety of reasons, and the final analysis therefore included 472 cases. Consensus readings were performed by three musculoskeletal radiologists using specific criteria to diagnose meniscoid labra. Results A meniscoid superior labrum was identified in 48 (10.2%) of the 472 cases evaluated. Arthroscopic proof was available in 21 cases (43.8%). In 10 (47.6%) of those 21 cases, the operative report did not include the mention a superior labral tear, thus suggesting the presence of a meniscoid labrum. In only one of those cases were there specific comments about a mobile superior labrum (i.e., meniscoid labrum). In the remaining 11 (52.4%), surgical correlation demonstrated superior labral tears. Conclusion A meniscoid superior labrum is not an infrequent finding. Depending upon assumptions and the requirement of surgical proof, the prevalence of a meniscoid superior labrum in this study was between 2.1% (surgically proven) and 4.8% (projected). However, superior labral tears are just as common and are often confused with meniscoid labra. PMID:27777474

  7. Evaluation of efficacy of dexmedetomidine versus propofol for sedation in children undergoing magnetic resonance imaging

    PubMed Central

    Kamal, Kirti; Asthana, Unnati; Bansal, Teena; Dureja, Jagdish; Ahlawat, Geeta; Kapoor, Saloni

    2017-01-01

    Background: A deep level of sedation is required for magnetic resonance imaging (MRI) in children to ensure optimum image quality. The present study was conducted to evaluate the efficacy and safety of dexmedetomidine versus propofol for sedation in children undergoing MRI. Materials and Methods: A total of sixty children aged 2–10 years, having physical status 1 or 2 according to the American Society of Anesthesiologists, undergoing MRI were included in the study. Group D: (n = 30) received injection dexmedetomidine 2 μg/kg for 10 min followed by continuous infusion of 1.0 μg/kg/h. Group P (n = 30) received injection propofol 1 mg/kg bolus followed by continuous infusion of 100 μg/kg/min. Results: The mean time for onset of sedation in Group D was much longer than in Group P (P = 0.000). Mean duration of sedation was comparable in the two groups. The number of patients requiring increased infusion of study drug was significantly higher in Group D (30%) as compared to Group P (16.7%) (P < 0.05). The average recovery time in Group D was much longer than in Group P (P < 0.001). Conclusion: Propofol had an advantage of providing rapid onset of sedation and quicker recovery time. Dexmedetomidine resulted in a better preservation of respiratory rate and oxygen saturation, so it may be more suitable in children who are prone to respiratory depression. Hence, both the drugs could achieve required sedation in children posted for MRI. PMID:28442954

  8. In vitro magnetic resonance imaging evaluation of ossicular implants at 3 T.

    PubMed

    Shellock, Frank G; Meepos, Lauren N; Stapleton, Matthew R; Valencerina, Sam

    2012-07-01

    Ossicular implants made from metallic materials may be acceptable or pose hazards for patients referred for magnetic resonance imaging (MRI) examinations, depending on the outcome of proper MRI testing procedures. Using a 3-T MR system, 2 ossicular implants were tested for magnetic field interactions, heating, and artifacts. Two different ossicular implants (Stainless Steel/Fluoroplastic Sanna-Type Piston [6 mm in length] and the Offset ALTO Total Prosthesis [15 mm in length, titanium/silicone]; Grace Medical, Memphis, TN, USA) were selected for testing, which represented the largest metallic mass and materials with the highest magnetic susceptibilities, with the intent of applying the MRI findings to other ossicular implants. The implants were evaluated at 3-T for magnetic field interactions, heating, and artifacts using standard previously described techniques. Each ossicular implant showed relatively minor magnetic field interactions that will not be associated with movement in situ. Heating was not excessive (highest temperature change, ≤ 1.6°C; background temperature change, 1.5°C). Artifacts, although relatively small, may create issues for diagnostic imaging if the area of interest is in the same area or close to these ossicular implants. The results of this investigation demonstrated that it would be acceptable (i.e., "MR conditional" using current terminology) for patients with these ossicular implants to undergo MRI examinations at 3 T or less. In consideration of the materials and dimensions of the implants that underwent testing, these findings pertain to many other similar ossicular implants from the same manufacturer.

  9. Evaluation of Angiographic and Technical Aspects of Carotid Stenting with Diffusion-Weighted Magnetic Resonance Imaging

    SciTech Connect

    Blasel, Stella Hattingen, Elke; Berkefeld, Joachim; Kurre, Wiebke; Morawe, Gerald; Zanella, Friedhelm; Rochemont, Richard Du Mesnil de

    2009-07-15

    The detection of clinically silent ischemic lesions on postprocedural diffusion-weighted magnetic resonance images has become a preferred method for the description of embolic risks. The purpose of this single-center study was to evaluate whether diffusion-weighted imaging (DWI) could determine material related or technical risk factors of filter-protected carotid stenting. Eighty-four patients with symptomatic severe ({>=}60%) carotid artery stenoses received filter-protected carotid stenting. Standard DWI (b = 1000) was performed within 48 h before and after carotid stenting. The occurrence and load of new postinterventional DWI lesions were assessed. Multivariate analysis was performed to determine risk factors associated with DWI lesions, with emphasis on technical factors such as use of different access devices (guiding catheter method vs. long carotid sheath method), type of stent (open-cell nitinol stent vs. closed-cell Wallstent), and protective device (filters with 80-{mu}m vs. 110-120-{mu}m pore size). Markers for generalized atherosclerosis and for degree and site of stenosis were assessed to allow comparison of adequate risk profiles. Access, protective device, and stent type were not significantly associated with new embolic DWI lesions when we compared patients with equivalent risk profiles (long carotid sheath method 48% [11 of 23] vs. guiding catheter method 44% [27 of 61], Wallstent 47% [15 of 32] vs. nitinol stent 44% [23 of 52], and small pore size filter 61% [11 of 18] vs. large pore size filter 41% [27 of 66]). Single-center DWI studies with a moderate number of cases are inadequate for proper assessment of the embolic risk of technical- or material-related risk factors in carotid stenting. Larger multicenter studies with more cases are needed.

  10. Active control of the volume acquisition noise in functional magnetic resonance imaging: Method and psychoacoustical evaluation

    NASA Astrophysics Data System (ADS)

    Chambers, John; Akeroyd, Michael A.; Summerfield, A. Quentin; Palmer, Alan R.

    2001-12-01

    Functional magnetic resonance imaging (fMRI) provides a noninvasive tool for observing correlates of neural activity in the brain while a subject listens to sound. However, intense acoustic noise is generated in the process of capturing MR images. This noise stimulates the auditory nervous system, limiting the dynamic range available for displaying stimulus-driven activity. The noise is potentially damaging to hearing and is distracting for the subject. In an active noise control (ANC) system, a reference sample of a noise is processed to form a sound which adds destructively with the noise at the listener's ear. We describe an implementation of ANC in the electromagnetically hostile and physically compact MRI scanning environment. First, a prototype system was evaluated psychoacoustically in the laboratory, using the electrical drive to a noise-generating loudspeaker as the reference. This system produced 10-20 dB of subjective noise-reduction between 250 Hz and 1 kHz, and smaller amounts at higher frequencies. The system was modified to operate in a real MR scanner where the reference was obtained by recording the acoustic scanner noise. Objective reduction by 30-40 dB of the most intense component in scanner noises was realized between 500 Hz and 3500 Hz, and subjective reduction of 12 dB and 5 dB in tests at frequencies of 600 Hz and at 1.9 kHz, respectively. Although the benefit of ANC is limited by transmission paths to the cochlea other than air-conduction routes from the auditory meatus, ANC achieves worthwhile attenuation even in the frequency range of maximum bone conduction (1.5-2 kHz). ANC should, therefore, be generally useful during auditory fMRI.

  11. Programmable infusion pump and catheter: evaluation using 3-tesla magnetic resonance imaging.

    PubMed

    Shellock, Frank G; Crivelli, Rocco; Venugopalan, Ramakrishna

    2008-07-01

    Objective.  This study assessed 3-Tesla magnetic resonance imaging (MRI) issues for a programmable infusion pump and associated catheters. Methods.  A programmable infusion pump and associated catheters (MedStream Programmable Infusion Pump, 40 mL; SureStream TI Coil-Reinforced Intraspinal Catheter; SureStream TI Connector; and SureStream Silicone Catheter; Codman and Shurtleff Inc., a Johnson & Johnson Company, Raynham, MA, USA) underwent evaluation for magnetic field interactions (deflection angle and torque), heating (transmit/receive body radiofrequency coil; whole-body averaged specific absorption rate, 3 W/kg for 15 min), functional changes (before and after MRI using eight different MRI conditions), and artifacts (T1-weighted spin-echo and gradient-echo pulse sequences) at 3-Tesla. Results.  The programmable infusion pump and associated catheters exhibited minor magnetic field interactions. Heating was not excessive (≤ 1.9°), especially considering the experimental conditions used for this evaluation (ie, relatively high radiofrequency power/specific absorption rate level and use of a nonperfused phantom). The function of three out of six pumps was temporarily altered by exposures to 3-Tesla MRI conditions. Reset was achieved in each case. Artifacts were relatively large for the pump and minor for the catheter. Conclusions.  The programmable infusion pump and catheters will not pose increased risk to a patient examined using 3-Tesla MRI as long as specific safety guidelines are followed, which includes interrogation of the pump post-MRI to ensure proper settings. Artifacts for the programmable infusion pump may impact the diagnostic use of MRI if the area of interest is in the same area or near the device.

  12. Multidetector Computed Tomography and Magnetic Resonance Imaging Evaluation of Craniovertebral junction Abnormalities

    PubMed Central

    Dhadve, Rajshree U.; Garge, Shaileshkumar S.; Vyas, Pooja D.; Thakker, Nirav R.; Shah, Sonali H.; Jaggi, Sunila T.; Talwar, Inder A.

    2015-01-01

    Background: Craniovertebral junction (CVJ) abnormalities constitute an important group of treatable neurological disorders with diagnostic dilemma. Their precise diagnosis, identification of probable etiology, and pretreatment evaluation significantly affects prognosis and quality of life of patients. Aims: The study was to classify various craniovertebral junction disorders according to their etiology and to define the importance of precise diagnosis for pretreatment evaluation with multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI). Materials and Methods: This is a prospective observational study of 62 patients referred to our department between October 2012 and September 2014. All patients suspected to have a craniovertebral junction disorder were included in the study, from all age groups and both genders. Detailed clinical history was taken. Radiographs of cervical spine were collected if available. All patients were subjected to MDCT and/or MRI. Results: In our study of 62 patients; 39 were males and 23 were females, with male to female ratio of 1.6:1. Most common age group was 2nd -3rd decade (19 patients, 30.64%). Developmental anomalies (33 patients, 53.22%) were the most common etiology group followed by traumatic (10 patients, 16.12%), degenerative (eight patients, 12.90%), infective (four patients, 6.45%), inflammatory and neoplastic (three patients each, 4.8%), and no cause found in one patient. Conclusions: CVJ abnormalities constitute an important group of treatable neurological disorders, especially in certain ethnic groups and are approached with much caution by clinicians. Thus, it is essential that radiologists should be able to make a precise diagnosis of craniovertebral junction abnormalities, classify them into etiological group, and rule out important mimickers on MDCT and/or MRI, as this information ultimately helps determine the management of such abnormalities, prognosis, and quality of life of patients. PMID

  13. Evaluation of a systematic approach to pediatric back pain: the utility of magnetic resonance imaging.

    PubMed

    Ramirez, Norman; Flynn, John M; Hill, Brian W; Serrano, Jose A; Calvo, Carlos E; Bredy, Rafael; Macchiavelli, Raul E

    2015-01-01

    Several studies have suggested that back pain in the majority of pediatric patients does not have an identifiable cause. Many children undergo extensive diagnostic workup that ultimately results in a nonconfirmative diagnosis. The purpose of this study was to (1) describe the prevalence of back pain seen in a pediatric orthopaedic clinic; (2) evaluate the efficacy of a systematic approach dependent on magnetic resonance imaging (MRI) in the diagnosis of pediatric back pain; and (3) analyze sensitivity, specificity, positive predictive value, and negative predictive value of various clinical signs and symptoms. For a 24-month period, all patients that presented with a chief complaint of back pain were prospectively enrolled in this study and evaluated in a systematic approach which utilized MRI for patients with constant pain, night pain, radicular pain, or abnormal neurological examination after an initial history, physical examination, and negative radiographic examination. The prevalence of chief complaint of back pain was 8.6% (261/3042 patients). Of the 261 patients, 34% had an identifiable pathology following the systematic approach. In 8.8% of patients, the diagnosis was established with the history, physical examination, and plain radiographs. MRI yielded a definitive diagnosis in another 25% of patients. It is noteworthy that of the 89 patients with a confirmed pathology, 26% were identified with plain radiographs and 74% with MRI. A systematic approach to diagnose pediatric back pain demonstrated that 34% of pediatric patients that present to an outpatient orthopaedic clinic complaining of back pain will have identifiable pathology. The diagnostic yield increased from 8.8% with the history, physical examination, and plain radiographs to 22% with the TCN Bone Scan to 36% with the use of the MRI. The clinician should be aware that the presences of lumbar pain or constant pain are red flags for the presence of underlying pathology. Level III.

  14. Comparison of postoperative magnetic resonance imaging and second-look arthroscopy for evaluating meniscal allograft transplantation.

    PubMed

    Kim, Jong-Min; Kim, Jong-Min; Jeon, Byeong-Sam; Lee, Chang-Rack; Lim, Sung-Joon; Kim, Kyung-Ah; Bin, Seong-Il

    2015-05-01

    The aim of this study was to compare the magnetic resonance imaging (MRI) evaluation of transplanted meniscal allograft with second-look arthroscopy and evaluate the sensitivity, specificity, and accuracy of MRI for assessing graft status. From 1996 to 2012, among 290 knees that underwent meniscal allograft transplantation and received follow-up examination for more than 1 year, those knees that underwent second-look arthroscopy were reviewed. Patients with no postoperative MRI and patients with a time gap between postoperative MRI and second-look arthroscopy of more than 3 months were excluded. Anatomically, the meniscus was divided into 3 segments: anterior one-third, mid body, and posterior one-third. Each part of the meniscus was evaluated using both methods. Grade 3 MRI signal intensity was diagnosed as a meniscal tear radiologically. By use of second-look arthroscopy as the standard, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of postoperative MRI were assessed in each segment of the grafts. Twenty knees were retrospectively enrolled. The specificity, PPV, and accuracy for the anterior one-third were lower than those for the mid body and posterior one-third (specificity of 35.3% v 91.7% and 90%, respectively; PPV of 21.4% v 87.5% and 90.9%, respectively; and accuracy of 45% v 90% and 95%, respectively). However, the sensitivity and NPV were similar among the anterior one-third, mid body, and posterior one-third (sensitivity of 100%, 87.5%, and 100%, respectively; and NPV of 100%, 91.7%, and 100%, respectively). There were no significant differences in the comparison between the diagnostic MRI values of lateral grafts and medial grafts. Of 5 cases that showed grade 3 signal at only the anterior one-third section, 60% had no clinical signs. There were no graft tears in any cases. The anterior one-third of grafts showed low specificity, PPV, and accuracy of postoperative MRI compared with the mid

  15. Fascicular Ratio: A New Parameter to Evaluate Peripheral Nerve Pathology on Magnetic Resonance Imaging

    PubMed Central

    Tagliafico, Alberto S.; Tagliafico, Giulio

    2014-01-01

    Abstract The objective of the study was to define and quantitatively evaluate the fascicular ratio (FR) on magnetic resonance imaging (MRI) in patients with peripheral neuropathies compared with healthy controls. Forty control subjects (20 women, 20 men; age, 44.6 ± 13.4 years) and 40 patients with peripheral neuropathy (22 women, 18 men; age, 50.3 ± 10.2 years) were examined with a standard 3T MRI protocol. With customized software (with semiautomatic and automatic interface), the hypointense and hyperintense areas of the peripheral nerves corresponding to fascicular and nonfascicular tissue were examined on T1-weighted sequences. The ratio of fascicular pixels to total pixels was called FR. Correlation with FR calculated on high-resolution ultrasound was performed. The statistical analysis included the Mann–Whitney U test of controls versus patients, the receiver operating characteristic (ROC) analysis, and the subgroup analysis of patients according to etiologies of neuropathy. Intraobserver and interobserver agreement was calculated based on the evaluation made by 3 readers. Finally, a complete automatic evaluation was performed. On MRI, FRs were significantly increased in patients compared with controls (FR, 76.7 ± 15.1 vs 56 ± 12.3; P < 0.0001 for the semiautomatic interface; and FR 66.3 ± 17.5 vs 47.8 ± 18.4; P < 0.0001 for the automatic interface). The increase in FR was caused mainly by an increase in the hypointense part of the nerve. This observation was valid for all causes of neuropathies. ROC analysis found an area under the curve of 0.75 (95% confidence interval, 0.44–0.81) for FR to discriminate neuropathy from control. The correlation coefficient between MRI and ultrasound was significant (r = 0.49; 95% confidence interval for r, 0.21–0.70; P = 0.012). With the semiautomated evaluation, the mean intraobserver agreement was good (K = 0.86). The interobserver agreements were also good (reader 1

  16. Magnetic resonance imaging in the evaluation of partial growth arrest after physeal injuries in children.

    PubMed

    Havránek, P; Lízler, J

    1991-09-01

    The precise delineation of the size, shape, and location of an osseous bridge is a critical step in the management of children who have a partial growth arrest of the epiphyseal plate. Five children between the ages of ten and fourteen years were diagnosed, with the aid of conventional roentgenograms, as having a partial growth arrest. Magnetic resonance-imaging studies were carried out to determine the exact size, shape, and location of the osseous bridge. The information derived from the imaging studies was essential for the determination of the appropriate treatment and for the planning and undertaking of any operative intervention.

  17. Evaluation of Magnetic Resonance Imaging-Compatible Needles and Interactive Sequences for Musculoskeletal Interventions Using an Open High-Field Magnetic Resonance Imaging Scanner

    SciTech Connect

    Wonneberger, Uta; Schnackenburg, Bernhard; Streitparth, Florian Walter, Thula Rump, Jens Teichgraeber, Ulf K. M.

    2010-04-15

    In this article, we study in vitro evaluation of needle artefacts and image quality for musculoskeletal laser-interventions in an open high-field magnetic resonance imaging (MRI) scanner at 1.0T with vertical field orientation. Five commercially available MRI-compatible puncture needles were assessed based on artefact characteristics in a CuSO4 phantom (0.1%) and in human cadaveric lumbar spines. First, six different interventional sequences were evaluated with varying needle orientation to the main magnetic field B0 (0{sup o} to 90{sup o}) in a sequence test. Artefact width, needle-tip error, and contrast-to-noise ratio (CNR) were calculated. Second, a gradient-echo sequence used for thermometric monitoring was assessed and in varying echo times, artefact width, tip error, and signal-to-noise ratio (SNR) were measured. Artefact width and needle-tip error correlated with needle material, instrument orientation to B0, and sequence type. Fast spin-echo sequences produced the smallest needle artefacts for all needles, except for the carbon fibre needle (width <3.5 mm, tip error <2 mm) at 45{sup o} to B0. Overall, the proton density-weighted spin-echo sequences had the best CNR (CNR{sub Muscle/Needle} >16.8). Concerning the thermometric gradient echo sequence, artefacts remained <5 mm, and the SNR reached its maximum at an echo time of 15 ms. If needle materials and sequences are accordingly combined, guidance and monitoring of musculoskeletal laser interventions may be feasible in a vertical magnetic field at 1.0T.

  18. The use of magnetic resonance imaging in evaluating horses with spinal ataxia.

    PubMed

    Mitchell, Colleen W; Nykamp, Stephanie G; Foster, Robert; Cruz, Robert; Montieth, Gabrielle

    2012-01-01

    To determine the accuracy of magnetic resonance imaging for diagnosing cervical stenotic myelopathy in horses, 39 horses with spinal ataxia and 20 control horses underwent clinical and neurologic examinations, cervical radiographs, euthanasia, magnetic resonance (MR) imaging of the cervical spine and necropsy. Twenty-four horses were diagnosed with cervical stenotic myelopathy, 5 with cervical vertebral stenosis, 7 with idiopathic ataxia, 3 horses had other causes of ataxia, and 20 were controls. The MR images were assessed for spinal cord intensity changes, presence of spinal cord compression, spinal cord compression direction, shape of spinal cord, and the presence of synovial cysts, joint mice, and degenerative joint disease. The height, width, and area of the spinal cord, dural tube and vertebral canal were measured. The identification of spinal cord compression on MR images was significantly different in horses with cervical stenotic myelopathy (P < 0.02), but in the cervical stenotic myelopathy group the identification of spinal cord compression on MR images had poor to slight agreement with histopathologic evidence of compression (κ = 0.05). Horses with cervical stenotic myelopathy were more likely to have a T2 hyperintensity in the spinal cord (P < 0.05). Horses with cervical stenotic myelopathy or cervical vertebral stenosis were more likely to have degenerative joint disease than control horses or horses with other or idiopathic ataxia. © 2012 Veterinary Radiology & Ultrasound.

  19. Magnetic Resonance Imaging in the Evaluation of Ductal Carcinoma In Situ

    PubMed Central

    2010-01-01

    Before 2000, breast magnetic resonance imaging (MRI) was considered a relatively poor imaging tool for ductal carcinoma in situ (DCIS), as a high percentage of false-negative magnetic resonance examinations were cases of DCIS. Three specific shifts in breast MRI occurred, which changed this assessment: 1) a shift from high temporal to high spatial imaging, revealing specific morphological features on MRI suspicious for DCIS; 2) a shift from diagnostic studies of patients with cancers identified on mammography to screening studies of high-risk patients, allowing more accurate comparisons of mammography vs MRI in detecting the full spectrum of breast cancers regardless of appearance on mammography; and 3) a shift from emphasis on masses to improved understanding of features of non–mass-like malignant lesions, distinct from benign background parenchymal enhancement patterns. Over the last decade, research has confirmed that of all imaging tools, MRI has the highest sensitivity in detection of DCIS (compared with mammography and ultrasound). Future studies are needed to clarify how best to use this tool for improved patient outcomes. PMID:20956821

  20. Magnetic resonance imaging in the evaluation of ductal carcinoma in situ.

    PubMed

    Lehman, Constance D

    2010-01-01

    Before 2000, breast magnetic resonance imaging (MRI) was considered a relatively poor imaging tool for ductal carcinoma in situ (DCIS), as a high percentage of false-negative magnetic resonance examinations were cases of DCIS. Three specific shifts in breast MRI occurred, which changed this assessment: 1) a shift from high temporal to high spatial imaging, revealing specific morphological features on MRI suspicious for DCIS; 2) a shift from diagnostic studies of patients with cancers identified on mammography to screening studies of high-risk patients, allowing more accurate comparisons of mammography vs MRI in detecting the full spectrum of breast cancers regardless of appearance on mammography; and 3) a shift from emphasis on masses to improved understanding of features of non-mass-like malignant lesions, distinct from benign background parenchymal enhancement patterns. Over the last decade, research has confirmed that of all imaging tools, MRI has the highest sensitivity in detection of DCIS (compared with mammography and ultrasound). Future studies are needed to clarify how best to use this tool for improved patient outcomes.

  1. Mastectomy Flap Thickness and Complications in Nipple-Sparing Mastectomy: Objective Evaluation using Magnetic Resonance Imaging.

    PubMed

    Frey, Jordan D; Salibian, Ara A; Choi, Mihye; Karp, Nolan S

    2017-08-01

    Ischemic complications after nipple-sparing mastectomy (NSM) have been associated with numerous variables. However, the impact of NSM flap thickness has been incompletely evaluated. NSM flap thickness was determined for all NSMs from 2006 to 2016 with available pre- or postoperative breast magnetic resonance imaging (MRIs). Demographics and outcomes were stratified by those with and without ischemic complications. Of 1,037 NSM reconstructions, 420 NSMs had MRI data available, which included 379 preoperative MRIs and 60 postoperative MRIs. Average total preoperative skin/subcutaneous tissue NSM flap thickness was 11.4 mm. Average total postoperative NSM flap thickness was 8.7 mm. NSMs with ischemic complications were found to have significantly thinner overall postoperative NSM flap thickness compared with those without ischemic complications (P = 0.0280). Average overall postoperative NSM flap thickness less than 8.0 mm was found to be an independent predictor of ischemic complications (odds ratio, 6.5263; P = 0.026). In NSMs with both pre- and postoperative MRIs, the overall average postoperative NSM flap thickness was 68.2% of preoperative measurements. Average overall postoperative NSM flap thickness was significantly less than average overall preoperative NSM flap thickness (P < 0.0001). NSMs with ischemic complications were found to have a significantly lower ratio of overall postoperative to preoperative flap thickness (52.0% versus 74.0%; P < 0.0001). Ischemic complications after NSM are significantly associated with thinner postoperative NSM flap thickness. Particularly, NSM flap thickness less than 8.0 mm is a positive independent predictor of ischemic complications. The ratio of postoperative to preoperative NSM flap thickness was significantly lower in reconstructions with ischemic complications.

  2. [Usefulness of magnetic resonance imaging in the evaluation of patellar malalignment].

    PubMed

    Figueroa, D; Novoa, F; Meleán, P; Calvo, R; Vaisman, A; Figueroa, F; Delgado, G

    2014-01-01

    The aim of this study is to evaluate the usefulness of Magnetic Resonance Imaging (MRI) at 20° of knee flexion in patients with patellofemoral pain syndrome (PFPS) caused by suspected patellofemoral malalignment (PFM). Fifty MRIs were performed on 25 patients with PFPS secondary to suspected PFM based on clinical examination, and on 25 patients without PFPS (control group). Measurements were made of tibial tuberosity-trochlear groove distance (TTTG) and modified Laurin, Merchant and trochlear angles. The results were analyzed with ANOVA and Fischer tests. Pearson correlation coefficients were used to analyze differences between PFPS and control cases. Specificity, sensitivity, positive predictive value and negative predictive value for knee pain were documented. Significant differences were observed between PFPS and control groups in TTTG (11.79 mm vs. 9.35 mm; P=.002), Laurin angle (12.17° vs. 15.56°; P=.05), and trochlear angle (139° vs. 130.02°; P=.049). No differences were found between groups as regards the Merchant angle (P=.5). TTTG was 70% predictive of PFPS; however, it was only 53.33% specific, with a sensitivity of 51.61% for PFPS. Laurin angle was 77.78% predictive of PFPS, with a specificity of 92% and a sensitivity of 28%. Trochlear angle was 85.71% predictive of PFPS, with a specificity of 96% and a sensitivity of 24%. MRI can confirm clinically suspected PFPS secondary to malalignment. MRI determination of TTTG, patellar tilt, and trochlear angle correlates positively with clinical diagnosis of PFPS, suggesting that PFPS is caused by subtle malalignment. Copyright © 2013 SECOT. Published by Elsevier Espana. All rights reserved.

  3. Magnetic resonance imaging of the coronary arteries: clinical results from three dimensional evaluation of a respiratory gated technique

    PubMed Central

    van Geuns, R J M; de Bruin, H G; Rensing, B; Wielopolski, P; Hulshoff, M; van Ooijen, P M A; Oudkerk, M; de Feyter, P J

    1999-01-01

    BACKGROUND—Magnetic resonance coronary angiography is challenging because of the motion of the vessels during cardiac contraction and respiration. Additional challenges are the small calibre of the arteries and their complex three dimensional course. Respiratory gating, turboflash acquisition, and volume rendering techniques may meet the necessary requirements for appropriate visualisation.
OBJECTIVE—To determine the diagnostic accuracy of respiratory gated magnetic resonance imaging (MRI) for the detection of significant coronary artery stenoses evaluated with three dimensional postprocessing software.
METHODS—32 patients referred for elective coronary angiography were studied with a retrospective respiratory gated three dimensional gradient echo MRI technique. Resolution was 1.9 × 1.25 × 2 mm. After manual segmentation three dimensional evaluation was performed with a volume rendering technique.
RESULTS—Overall 74% (range 50% to 90%) of the proximal and mid coronary artery segments were visualised with an image quality suitable for further analysis. Sensitivity and specificity for the detection of significant stenoses were 50% and 91%, respectively.
CONCLUSIONS—Volume rendering of respiratory gated MRI techniques allows adequate visualisation of the coronary arteries in patients with a regular breathing pattern. Significant lesions in the major coronary artery branches can be identified with a moderate sensitivity and a high specificity.


Keywords: magnetic resonance imaging; coronary artery disease; coronary angiography; computer assisted image processing PMID:10490571

  4. Advanced techniques in magnetic resonance imaging in the evaluation of the large endolymphatic duct and sac syndrome.

    PubMed

    Harnsberger, H R; Dahlen, R T; Shelton, C; Gray, S D; Parkin, J L

    1995-10-01

    The purpose of this report is to compare temporal bone computed tomography (CT) to high-resolution magnetic resonance (MR) imaging using a novel thin-section fast spin echo (FSE) pulse sequence in identifying and characterizing patients with large vestibular aqueduct syndrome. Sixteen patients with sensorineural hearing loss and a CT diagnosis of large vestibular aqueduct(s) underwent high-resolution fast spin echo magnetic resonance imaging with dual, 3-in phased array receiver coils centered over the external auditory canals. Magnetic resonance imaging parameters included axial and oblique sagittal fast spin echo with an effective slice thickness of 1 mm contiguous. Thirty-eight patients with 76 normal inner ears who underwent MR imaging using this technique had their endolymphatic duct measured. MR alone identified the enlarged endolymphatic sac seen along with the large endolymphatic duct in all cases. Three cases (five inner ears) with enlarged bony vestibular aqueducts on CT showed no evidence of endolymphatic duct or sac enlargement on MR. MR alone identified a single case of mild cochlear anomaly in conjunction with an enlarged endolymphatic duct and sac. In the normal population the size of the normal endolymphatic duct at its midpoint measured from 0.1 to 1.4 mm. Thin-section, high-resolution fast spin echo MR imaging of the inner ear may be superior to CT in the evaluation of patients with the large vestibular aqueduct syndrome.

  5. [Magnetic resonance imaging in the evaluation in utero of Siamese twins].

    PubMed

    Cosson, M; Vinatier, D; Patey, P; Maunoury-Lefebvre, C; Bartkowiak, D; Sault, M C; Monnier, J C

    1990-01-01

    The authors report a case of twins conjoined at the umbilicus and diagnosed by ultrasound after 19 weeks of amenorrhoea in whom an assessment in utero was carried out using magnetic resonance imaging after the patient had been curarized. A review of the literature on this very difficult problem of conjoined twins has given us the possibility to assess the diagnostic measures as well as the prognosis of this pathology. In particular we point out the results that can be obtained using MRI in utero during the second and third trimesters of the pregnancy.

  6. [Evaluation of cardiac tumors by multidetector computed tomography and magnetic resonance imaging].

    PubMed

    Mercado-Guzman, Marcela P; Meléndez-Ramírez, Gabriela; Castillo-Castellon, Francisco; Kimura-Hayama, Eric

    Cardiac tumors, are a rare pathology (0.002-0.3%) in all age groups, however, they have a clinic importance, due the affected organ. They are classified in primary (benign or malignant) and secondary (metastasis) types. Among primary type, mixoma, is the most common benign tumor, and sarcoma represents most of the malignant injuries. Cardiac metastasis are more frequent than primary tumors. Clinic effects of cardiac tumors are unspecific and vary according their location, size and agresivity. The use of Multidetector Computed Tomography (MDCT) and Magnetic Resonance Imaging (MRI) assist on the location, sizing, anatomical relationships and the compromise of adyacents structures, besides, MRI is useful for tissue characterization of the tumor. Due to the previous reasons, studies based on noninvasive cardiovascular imaging, have an important role on the characterization of these lesions and the differential diagnosis among them.

  7. Exploratory use of cardiovascular magnetic resonance imaging in liver transplantation: a one-stop shop for preoperative cardiohepatic evaluation.

    PubMed

    Reddy, Sahadev T; Thai, Ngoc L; Fakhri, Asghar A; Oliva, Jose; Tom, Kusum B; Dishart, Michael K; Doyle, Mark; Yamrozik, June A; Williams, Ronald B; Grant, Saundra B; Poydence, Jacqueline; Shah, Moneal; Singh, Anil; Nathan, Swami; Biederman, Robert W W

    2013-11-15

    Preoperative cardiovascular risk stratification in orthotopic liver transplantation candidates has proven challenging due to limitations of current noninvasive modalities. Additionally, the preoperative workup is logistically cumbersome and expensive given the need for separate cardiac, vascular, and abdominal imaging. We evaluated the feasibility of a "one-stop shop" in a magnetic resonance suite, performing assessment of cardiac structure, function, and viability, along with simultaneous evaluation of thoracoabdominal vasculature and liver anatomy. In this pilot study, patients underwent steady-state free precession sequences and stress cardiac magnetic resonance (CMR), thoracoabdominal magnetic resonance angiography, and abdominal magnetic resonance imaging (MRI) on a standard MRI scanner. Pharmacologic stress was performed using regadenoson, adenosine, or dobutamine. Viability was assessed using late gadolinium enhancement. Over 2 years, 51 of 77 liver transplant candidates (mean age, 56 years; 35% female; mean Model for End-stage Liver Disease score, 10.8; range, 6-40) underwent MRI. All referred patients completed standard dynamic CMR, 98% completed stress CMR, 82% completed late gadolinium enhancement for viability, 94% completed liver MRI, and 88% completed magnetic resonance angiography. The mean duration of the entire study was 72 min, and 45 patients were able to complete the entire examination. Among all 51 patients, 4 required follow-up coronary angiography (3 for evidence of ischemia on perfusion CMR and 1 for postoperative ischemia), and none had flow-limiting coronary disease. Nine proceeded to orthotopic liver transplantation (mean 74 days to transplantation after MRI). There were six ascertained mortalities in the nontransplant group and one death in the transplanted group. Explant pathology confirmed 100% detection/exclusion of hepatocellular carcinoma. No complications during CMR examination were encountered. In this proof-of-concept study, it

  8. SU-E-J-157: Improving the Quality of T2-Weighted 4D Magnetic Resonance Imaging for Clinical Evaluation

    SciTech Connect

    Du, D; Mutic, S; Hu, Y; Caruthers, S; Glide-Hurst, C; Low, D

    2014-06-01

    Purpose: To develop an imaging technique that enables us to acquire T2- weighted 4D Magnetic Resonance Imaging (4DMRI) with sufficient spatial coverage, temporal resolution and spatial resolution for clinical evaluation. Methods: T2-weighed 4DMRI images were acquired from a healthy volunteer using a respiratory amplitude triggered T2-weighted Turbo Spin Echo sequence. 10 respiratory states were used to equally sample the respiratory range based on amplitude (0%, 20%i, 40%i, 60%i, 80%i, 100%, 80%e, 60%e, 40%e and 20%e). To avoid frequent scanning halts, a methodology was devised that split 10 respiratory states into two packages in an interleaved manner and packages were acquired separately. Sixty 3mm sagittal slices at 1.5mm in-plane spatial resolution were acquired to offer good spatial coverage and reasonable spatial resolution. The in-plane field of view was 375mm × 260mm with nominal scan time of 3 minutes 42 seconds. Acquired 2D images at the same respiratory state were combined to form the 3D image set corresponding to that respiratory state and reconstructed in the coronal view to evaluate whether all slices were at the same respiratory state. 3D image sets of 10 respiratory states represented a complete 4D MRI image set. Results: T2-weighted 4DMRI image were acquired in 10 minutes which was within clinical acceptable range. Qualitatively, the acquired MRI images had good image quality for delineation purposes. There were no abrupt position changes in reconstructed coronal images which confirmed that all sagittal slices were in the same respiratory state. Conclusion: We demonstrated it was feasible to acquire T2-weighted 4DMRI image set within a practical amount of time (10 minutes) that had good temporal resolution (10 respiratory states), spatial resolution (1.5mm × 1.5mm × 3.0mm) and spatial coverage (60 slices) for future clinical evaluation.

  9. Cardiovascular Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Pelc, Norbert

    2000-03-01

    Cardiovascular diseases are a major source of morbidity and mortality in the United States. Early detection of disease can often be used to improved outcomes, either through direct interventions (e.g. surgical corrections) or by causing the patient to modify his or her behavior (e.g. smoking cessation or dietary changes). Ideally, the detection process should be noninvasive (i.e. it should not be associated with significant risk). Magnetic Resonance Imaging (MRI) refers to the formation of images by localizing NMR signals, typically from protons in the body. As in other applications of NMR, a homogeneous static magnetic field ( ~0.5 to 4 T) is used to create ``longitudinal" magnetization. A magnetic field rotating at the Larmor frequency (proportional to the static field) excites spins, converting longitudinal magnetization to ``transverse" magnetization and generating a signal. Localization is performed using pulsed gradients in the static field. MRI can produce images of 2-D slices, 3-D volumes, time-resolved images of pseudo-periodic phenomena such as heart function, and even real-time imaging. It is also possible to acquire spatially localized NMR spectra. MRI has a number of advantages, but perhaps the most fundamental is the richness of the contrast mechanisms. Tissues can be differentiated by differences in proton density, NMR properties, and even flow or motion. We also have the ability to introduce substances that alter NMR signals. These contrast agents can be used to enhance vascular structures and measure perfusion. Cardiovascular MRI allows the reliable diagnosis of important conditions. It is possible to image the blood vessel tree, quantitate flow and perfusion, and image cardiac contraction. Fundamentally, the power of MRI as a diagnostic tool stems from the richness of the contrast mechanisms and the flexibility in control of imaging parameters.

  10. Quantitative Evaluation of Mitral Regurgitation Secondary to Mitral Valve Prolapse by Magnetic Resonance Imaging and Echocardiography.

    PubMed

    Le Goffic, Caroline; Toledano, Manuel; Ennezat, Pierre-Vladimir; Binda, Camille; Castel, Anne-Laure; Delelis, François; Graux, Pierre; Tribouilloy, Christophe; Maréchaux, Sylvestre

    2015-11-01

    The present prospective study was designed to evaluate the accuracy of quantitative assessment of mitral regurgitant fraction (MRF) by echocardiography and cardiac magnetic resonance imaging (cMRI) in the modern era using as reference method the blinded multiparametric integrative assessment of mitral regurgitation (MR) severity. 2-Dimensional (2D) and 3-dimensional (3D) MRF by echocardiography (2D echo MRF and 3D echo MRF) were obtained by measuring the difference in left ventricular (LV) total stroke volume (obtained from either 2D or 3D acquisition) and aortic forward stroke volume normalized to LV total stroke volume. MRF was calculated by cMRI using either (1) (LV stroke volume - systolic aortic outflow volume by phase contrast)/LV stroke volume (cMRI MRF [volumetric]) or (2) (mitral inflow volume - systolic aortic outflow volume)/mitral inflow volume (cMRI MRF [phase contrast]). Six patients had 1 + MR, 6 patients had 2 + MR, 12 patients had 3 + MR, and 10 had 4 + MR. A significant correlation was observed between MR grading and 2D echo MRF (r = 0.60, p <0.0001) and 3D echo MRF (r = 0.79, p <0.0001), cMRI MRF (volumetric) (r = 0.87, p <0.0001), and cMRI MRF (phase contrast r = 0.72, p <0.001). The accuracy of MRF for the diagnosis of MR ≥3+ or 4+ was the highest with cMRI MRF (volumetric) (area under the receiver-operating characteristic curve [AUC] = 0.98), followed by 3D echo MRF (AUC = 0.96), 2D echo MRF (AUC = 0.90), and cMRI MRF (phase contrast; AUC = 0.83). In conclusion, MRF by cMRI (volumetric method) and 3D echo MRF had the highest diagnostic value to detect significant MR, whereas the diagnostic value of 2D echo MRF and cMRI MRF (phase contrast) was lower. Hence, the present study suggests that both cMRI (volumetric method) and 3D echo represent best approaches for calculating MRF.

  11. Evaluating Swallowing Muscles Essential for Hyolaryngeal Elevation by Using Muscle Functional Magnetic Resonance Imaging

    SciTech Connect

    Pearson, William G.; Hindson, David F.; Langmore, Susan E.; Zumwalt, Ann C.

    2013-03-01

    Purpose: Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. Methods and Materials: mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Results: Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Conclusions

  12. Evaluating swallowing muscles essential for hyolaryngeal elevation by using muscle functional magnetic resonance imaging.

    PubMed

    Pearson, William G; Hindson, David F; Langmore, Susan E; Zumwalt, Ann C

    2013-03-01

    Reduced hyolaryngeal elevation, a critical event in swallowing, is associated with radiation therapy. Two muscle groups that suspend the hyoid, larynx, and pharynx have been proposed to elevate the hyolaryngeal complex: the suprahyoid and longitudinal pharyngeal muscles. Thought to assist both groups is the thyrohyoid, a muscle intrinsic to the hyolaryngeal complex. Intensity modulated radiation therapy guidelines designed to preserve structures important to swallowing currently exclude the suprahyoid and thyrohyoid muscles. This study used muscle functional magnetic resonance imaging (mfMRI) in normal healthy adults to determine whether both muscle groups are active in swallowing and to test therapeutic exercises thought to be specific to hyolaryngeal elevation. mfMRI data were acquired from 11 healthy subjects before and after normal swallowing and after swallowing exercise regimens (the Mendelsohn maneuver and effortful pitch glide). Whole-muscle transverse relaxation time (T2 signal, measured in milliseconds) profiles of 7 test muscles were used to evaluate the physiologic response of each muscle to each condition. Changes in effect size (using the Cohen d measure) of whole-muscle T2 profiles were used to determine which muscles underlie swallowing and swallowing exercises. Post-swallowing effect size changes (where a d value of >0.20 indicates significant activity during swallowing) for the T2 signal profile of the thyrohyoid was a d value of 0.09; a d value of 0.40 for the mylohyoid, 0.80 for the geniohyoid, 0.04 for the anterior digastric, and 0.25 for the posterior digastric-stylohyoid in the suprahyoid muscle group; and d values of 0.47 for the palatopharyngeus and 0.28 for the stylopharyngeus muscles in the longitudinal pharyngeal muscle group. The Mendelsohn maneuver and effortful pitch glide swallowing exercises showed significant effect size changes for all muscles tested, except for the thyrohyoid. Muscles of both the suprahyoid and the longitudinal

  13. Evaluation of a motion artifacts removal approach on breath-hold cine-magnetic resonance images of hypertrophic cardiomyopathy subjects

    NASA Astrophysics Data System (ADS)

    Betancur, Julián.; Simon, Antoine; Schnell, Frédéric; Donal, Erwan; Hernández, Alfredo; Garreau, Mireille

    2013-11-01

    The acquisition of ECG-gated cine magnetic resonance images of the heart is routinely performed in apnea in order to suppress the motion artifacts caused by breathing. However, many factors including the 2D nature of the acquisition and the use of di erent beats to acquire the multiple-view cine images, cause this kind of artifacts to appear. This paper presents the qualitative evaluation of a method aiming to remove motion artifacts in multipleview cine images acquired on patients with hypertrophic cardiomyopathy diagnosis. The approach uses iconic registration to reduce for in-plane artifacts in long-axis-view image stacks and in-plane and out-of-plane motion artifacts in sort-axis-view image stack. Four similarity measures were evaluated: the normalized correlation, the normalized mutual information, the sum of absolute voxel di erences and the Slomka metric proposed by Slomka et al. The qualitative evaluation assessed the misalignment of di erent anatomical structures of the left ventricle as follows: the misalignment of the interventricular septum and the lateral wall for short-axis-view acquisitions and the misalignment between the short-axis-view image and long-axis-view images. Results showed the correction using the normalized correlation as the most appropriated with an 80% of success.

  14. Radiation-Induced Damage to Microstructure of Parotid Gland: Evaluation Using High-Resolution Magnetic Resonance Imaging

    SciTech Connect

    Kan, Tomoko; Kodani, Kazuhiko; Michimoto, Koichi; Fujii, Shinya; Ogawa, Toshihide

    2010-07-15

    Purpose: To elucidate the radiation-induced damage to the microstructure of the parotid gland using high-resolution magnetic resonance imaging. Methods and Materials: High-resolution magnetic resonance imaging of the parotid gland was performed before radiotherapy (RT) and during the RT period or {<=}3 weeks after RT completion for 12 head-and-neck cancer patients using a 1.5-T scanner with a microscopy coil. The maximal cross-sectional area of the gland was evaluated, and changes in the internal architecture of the gland were assessed both visually and quantitatively. Results: Magnetic resonance images were obtained at a median parotid gland dose of 36 Gy (range, 11-64). According to the quantitative analysis, the maximal cross-sectional area of the gland was reduced, the width of the main duct was narrowed, and the intensity ratio of the main duct lumen to background was significantly decreased after RT (p <.0001). According to the visual assessment, the width of the main duct tended to narrow and the contrast of the duct lumen tended to be decreased, but no significant differences were noted. The visibility of the duct branches was unclear in 10 patients (p = .039), and the septum became dense in 11 patients (p = .006) after RT. Conclusion: High-resolution magnetic resonance imaging is a noninvasive method of evaluating radiation-induced changes to the internal architecture of the parotid gland. Morphologic changes in the irradiated parotid gland were demonstrated during the RT course even when a relatively small dose was delivered to the gland.

  15. Evaluation of congenital heart disease by cine magnetic resonance imaging (MRI)

    SciTech Connect

    Feiglin, D.H.I.; Moodie, D.S.; O'Donnell, J.K.; Go, R.T.; Sterba, R.; MacIntyre, W.J.

    1985-05-01

    The authors studied 11 adult patients (pts) with atrial septal defect (ASD) and 4 adult pts with ventricular septal defect (VSD) using cine magnetic resonance. All studies were performed using a .6T superconducting magnet with ECG gating and electronic axial rotation when appropriate. Repeated multislice image with no change in physiologic delay of the spin echo pulse sequence, but varying the time by offsetting one slice at each imaging stage allowed for an N x N collection of data where N is the number of slices in one collection set and is equal to the number of sets collected. Algebraic manipulation of the T1 weighted images (TE=30mSec TRimaging of the atrial septum than does conventional MRI. Using this technique, the authors have identified both atrial and ventricular septal defects in all pts preoperatively and have noted an intact atrial septum following surgery. Standard MRI produced 4 false positive studies postoperatively because only 1 phase of the cardiac cycle was reviewed. Cine MRI allows better identification of septal defects than standard static acquisitions. The cine technique also provides better definition and delineation of right sided abnormalities which are maximized when viewed in a cardiac major axis obtained by electronic axial rotation.

  16. Evaluation of spatial-encoding-related geometric distortion in magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Hong, Cheol Pyo; Lee, Dong Hoon; Lee, Man Woo; Woo, Youngkeun

    2012-12-01

    This study demonstrated the characteristics of spatial encoding-related geometric distortion in magnetic resonance imaging (MRI) by using a phantom with known physical dimensions to detect geometric distortion in MR scans. The amount of distortion was calculated as the difference between the physical coordinates of control points in the phantom and those of the corresponding points in the distorted MR image of the phantom. The phase and the frequency encoding directions were swapped to acquire a phantom image for movement of a patient table 120 mm to the right and left, allowing comprehensive distortion mapping over the isocentric plane and the entire field of view (FOV) along the spatial encoding. The geometric distortion of phase encoding directions over the entire FOV was small compared to the distortion of frequency encoding directions. The maximum absolute deviations were 28.00 mm and 20.00 mm along the frequency and the phase encoding directions over the entire FOV, respectively. The mean absolute deviations along the frequency and the phase encoding directions were 2.85 mm and 1.97 mm, respectively. Although geometric distortion along the phase encoding axis near the isocenter was small, the distortion increased slightly toward the peripheral regions. The distortion of the phase encoding direction in the peripheral region can be severely affected by the imaging gradient's nonlinearity.

  17. Intrathoracic splenosis: evaluation by superparamagnetic iron oxide-enhanced magnetic resonance imaging and radionuclide scintigraphy.

    PubMed

    Ishibashi, Mana; Tanabe, Yoshio; Miyoshi, Hidenao; Matusue, Eiji; Kaminou, Toshio; Ogawa, Toshihide

    2009-11-01

    Splenosis represents the heterotopic autotransplantation of splenic tissue after either splenic trauma or surgery. Intrathoracic splenosis is a rare condition resulting from concomitant rupture of the spleen and the left hemidiaphragm. We report a case of splenosis in a 41-year-old male patient who had experienced severe thoracoabdominal injury including rupture of the spleen and left hemidiaphragm and post-traumatic splenectomy 20 years previously. Abnormal opacities in the cardiac region were noted on a chest radiograph at an annual checkup. Computed tomography (CT) of the chest demonstrated multiple, well-circumscribed pleura-based nodules at the posterior base of the left hemithorax and the left subdiaphragmatic area. On magnetic resonance imaging (MRI), the lesions were hypointense on T1-weighted images and hyperintense on T2-weighted images. After administration of superparamagnetic iron oxide (SPIO), the lesions showed decreased signal intensity but remained slightly hyperintense relative to liver parenchyma on T2-weighted images. (99m)Tc-labeled Sn colloid scintigraphy revealed multiple areas of increased activity consistent with the lesions on the CT and MRI scans. In addition to the history of splenic trauma and left hemothorax, SPIO-enhanced MRI and radionuclide scintigraphy, which can demonstrate phagocytic ability in the ectopic splenic tissue, were useful for confirming the diagnosis.

  18. AN EVALUATION OF DIFFERENT METHODS FOR MEASURING LATERAL TIBIAL SLOPE USING MAGNETIC RESONANCE IMAGING

    PubMed Central

    Lipps, David B.; Wilson, Annie M.; Ashton-Miller, James A.; Wojtys, Edward M.

    2014-01-01

    Background Since lateral tibial slope (LTS) affects the amount of anterior tibial translation and anterior cruciate ligament (ACL) strain during a dynamic maneuver, accurate measurements of lateral tibial slope may be beneficial in screening individuals at a higher risk for ACL injury. Methods for measuring LTS on magnetic resonance imaging scans of the proximal tibia include the midpoint and circle methods. There are no current studies that have validated different LTS measurements methods using a proximal tibia magnetic resonance imaging scan. Hypothesis We tested the null hypotheses that (1) LTS measurements were independent of the length of tibia imaged using the midpoint method, and (2) LTS measurements calculated from different methods (‘midpoint’, ‘circle’, and ‘full tibia’) would not differ significantly. Study Design Descriptive Laboratory Study Methods Blinded observers measured LTS from 3-Tesla 3D magnetic resonance images from 40 size-matched donors according to one circle method and three midpoint methods. Outcomes were then compared to the full tibial anatomical axis (line connecting the center of two circles fit within the proximal and distal tibia) in 11 donors. Bonferroni-correct paired t-tests (p < 0.005 significant) were used to compare the five methods. Results The circle and full tibia methods had the lowest inter- and intra-observer variability, while the midpoint method with 10 cm tibia was the most variable. The midpoint method with 10cm and 15 cm proximal tibia closely resembled LTS measurements with the full tibia anatomic axis. The circle method, while repeatable, provided smaller numerical LTS measurements than the full tibia and midpoint methods. Conclusions While LTS measurements using the midpoint method can resemble measurements made using the full tibia, the reliability of the midpoint method depends on the length of proximal tibia used. The circle method may be the preferred method for future studies since it was the

  19. The evaluation of arthroscopic remplissage by high-resolution magnetic resonance imaging.

    PubMed

    Park, Min Jung; Garcia, Grant; Malhotra, Amit; Major, Nancy; Tjoumakaris, Fotios P; Kelly, John D

    2012-10-01

    Arthroscopic remplissage is a novel procedure recently advocated for the treatment of large Hill-Sachs lesions with recurrent anterior glenohumeral instability. We have shown previously that infraspinatus tenodesis and Bankart repair reduce the risk of recurrent instability in high-risk patients. The ability to perform this procedure arthroscopically and without the need for bone grafting or an open approach makes this an appealing alternative to more traditional techniques. To evaluate and characterize the postoperative appearance of the remplissage procedure on high-resolution magnetic resonance imaging (MRI) and to correlate these findings to clinical outcome (Western Ontario Shoulder Instability [WOSI] score, range of motion). Case series; Level of evidence, 4. In patients who had undergone arthroscopic remplissage for recurrent glenohumeral instability with large Hill-Sachs defects, images were acquired with a 3-T protocol (and reviewed by 2 musculoskeletal radiologists) with the shoulder in the abduction-external rotation (ABER) and neutral positions at the time of the latest clinical examination. Measured parameters included signal intensity of tissue within the prior defect, signal intensity of the residual infraspinatus, degree of fatty infiltrate and muscle atrophy as a percentage of fat signal versus muscle signal (Goutallier grade), presence of marrow edema, and number of anchors in the defect. Functional scores were obtained with the WOSI questionnaire, and comprehensive range of motion data were recorded with a goniometer. In 11 patients with an average clinical follow-up of 18.0 months (range, 8.8-27.2 months), the average size of the Hill-Sachs deformity was 334.3 mm(3) (range, 93.6-825.1 mm(3)). The percentage of the deformity filled in with tendon was 75% to 100%, and the degree of atrophy was 0% to 25% for all patients studied. No defects were left unfilled. Two patients had granulation tissue filling the lesion, and 3 patients had fibrous tissue

  20. Magnetic Resonance Imaging as an Adjunct to Ultrasound in Evaluating Cesarean Scar Ectopic Pregnancy

    PubMed Central

    Wu, Rebecca; Klein, Michelle A.; Mahboob, Sabrina; Gupta, Mala; Katz, Douglas S.

    2013-01-01

    Cesarean scar pregnancies (CSPs) are a relatively rare form of ectopic pregnancy in which the embryo is implanted within the fibrous scar of a previous cesarean section. A greater number of cases of CSPs are currently being reported as the rates of cesarean section are increasing globally and as detection of scar pregnancy has improved with use of transvaginal ultrasound (TVUS) with color Doppler imaging. Delayed diagnosis and management of this potentially life-threatening condition may result in complications, predominantly uterine rupture and hemorrhage with significant potential maternal morbidity. Diagnosis of a cesarean scar pregnancy (CSP) requires a high index of clinical suspicion, as up to 40% of patients may be asymptomatic. TVUS has a reported sensitivity of 84.6% and has become the imaging examination of choice for diagnosis of a CSP. Magnetic resonance imaging (MRI) has been used in a small number of patients as an adjunct to TVUS. In the present report, MRI is highlighted as a problem-solving tool capable of more precisely identifying the relationship of a CSP to adjacent structures, thereby providing additional information critical to directing appropriate patient management and therapy. PMID:23814688

  1. Magnetic resonance imaging as an adjunct to ultrasound in evaluating cesarean scar ectopic pregnancy.

    PubMed

    Wu, Rebecca; Klein, Michelle A; Mahboob, Sabrina; Gupta, Mala; Katz, Douglas S

    2013-01-01

    Cesarean scar pregnancies (CSPs) are a relatively rare form of ectopic pregnancy in which the embryo is implanted within the fibrous scar of a previous cesarean section. A greater number of cases of CSPs are currently being reported as the rates of cesarean section are increasing globally and as detection of scar pregnancy has improved with use of transvaginal ultrasound (TVUS) with color Doppler imaging. Delayed diagnosis and management of this potentially life-threatening condition may result in complications, predominantly uterine rupture and hemorrhage with significant potential maternal morbidity. Diagnosis of a cesarean scar pregnancy (CSP) requires a high index of clinical suspicion, as up to 40% of patients may be asymptomatic. TVUS has a reported sensitivity of 84.6% and has become the imaging examination of choice for diagnosis of a CSP. Magnetic resonance imaging (MRI) has been used in a small number of patients as an adjunct to TVUS. In the present report, MRI is highlighted as a problem-solving tool capable of more precisely identifying the relationship of a CSP to adjacent structures, thereby providing additional information critical to directing appropriate patient management and therapy.

  2. Preclinical and clinical evaluation of the liver tumor irreversible electroporation by magnetic resonance imaging

    PubMed Central

    Figini, Matteo; Wang, Xifu; Lyu, Tianchu; Su, Zhanliang; Procissi, Daniele; Yaghmai, Vahid; Larson, Andrew C; Zhang, Zhuoli

    2017-01-01

    Irreversible electroporation (IRE) is a relatively new technique for tumor ablation. It has shown promising results in difficult cases where surgery is not recommended and delicate anatomic structures are present near or within the tumor. Currently, liver cancer is one of the most common targets for IRE treatment. Pre-operative and post-operative imaging has a key role in IRE procedures and research studies. Although ultrasound is usually the first choice, especially for intra-operative guidance, magnetic resonance imaging (MRI) plays an important role in the visualization and characterization of tumor before and after IRE in clinical and preclinical studies. However, the appearance of liver lesions after IRE with different MRI sequences has never been systematically investigated, and the most common practice is to limit the acquisition protocol to only contrast-enhanced T1-weighted images. In this work, the role of MRI in clinical and preclinical assessment of hepatic tumors treated with IRE is reviewed and discussed. PMID:28337285

  3. Evaluation of motion and its effect on brain magnetic resonance image quality in children.

    PubMed

    Afacan, Onur; Erem, Burak; Roby, Diona P; Roth, Noam; Roth, Amir; Prabhu, Sanjay P; Warfield, Simon K

    2016-11-01

    Motion artifacts pose significant problems for the acquisition of MR images in pediatric populations. To evaluate temporal motion metrics in MRI scanners and their effect on image quality in pediatric populations in neuroimaging studies. We report results from a large pediatric brain imaging study that shows the effect of motion on MRI quality. We measured motion metrics in 82 pediatric patients, mean age 13.4 years, in a T1-weighted brain MRI scan. As a result of technical difficulties, 5 scans were not included in the subsequent analyses. A radiologist graded the images using a 4-point scale ranging from clinically non-diagnostic because of motion artifacts to no motion artifacts. We used these grades to correlate motion parameters such as maximum motion, mean displacement from a reference point, and motion-free time with image quality. Our results show that both motion-free time (as a ratio of total scan time) and average displacement from a position at a fixed time (when the center of k-space was acquired) were highly correlated with image quality, whereas maximum displacement was not as good a predictor. Among the 77 patients whose motion was measured successfully, 17 had average displacements of greater than 0.5 mm, and 11 of those (14.3%) resulted in non-diagnostic images. Similarly, 14 patients (18.2%) had less than 90% motion-free time, which also resulted in non-diagnostic images. We report results from a large pediatric study to show how children and young adults move in the MRI scanner and the effect that this motion has on image quality. The results will help the motion-correction community in better understanding motion patterns in pediatric populations and how these patterns affect MR image quality.

  4. Evaluation of stress-related anterior lower leg pain with magnetic resonance imaging and intracompartmental pressure measurement.

    PubMed

    Kiuru, Martti J; Mantysaari, Matti J; Pihlajamaki, Harri K; Ahovuo, Juhani A

    2003-01-01

    The purpose of this work was to evaluate stress-related anterior lower leg pain with clinical examination, magnetic resonance imaging, and measurement of anterior tibial compartment pressure findings. All medical data were gathered from 24 conscripts with stress-related anterior lower leg pain. Twenty exhibited bilateral symptoms. In 22 of the 44 cases, the intracompartmental pressure was pathological. Symptoms were exhibited for longer periods by patients with chronic exertional compartment syndrome (CECS) than by other patients (p < 0.01). At rest, magnetic resonance imaging revealed no abnormal findings in the soft tissues of the legs but showed bone abnormalities in 35 symptomatic legs. Thirty-three exhibited bone stress injuries, and two exhibited leg traction periostitis. On magnetic resonance imaging, there was no difference in bone findings between patients with and without CECS (p > 0.05). Stress-related anterior lower leg pain can be related to CECS, bone stress injury, and traction periostitis. Clinical diagnosis is unreliable. CECS and bone stress injury or traction periostitis can occur separately or together.

  5. Partially orthogonal resonators for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R.

    2017-02-01

    Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density.

  6. Partially orthogonal resonators for magnetic resonance imaging

    PubMed Central

    Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R.

    2017-01-01

    Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density. PMID:28186135

  7. Partially orthogonal resonators for magnetic resonance imaging.

    PubMed

    Chacon-Caldera, Jorge; Malzacher, Matthias; Schad, Lothar R

    2017-02-10

    Resonators for signal reception in magnetic resonance are traditionally planar to restrict coil material and avoid coil losses. Here, we present a novel concept to model resonators partially in a plane with maximum sensitivity to the magnetic resonance signal and partially in an orthogonal plane with reduced signal sensitivity. Thus, properties of individual elements in coil arrays can be modified to optimize physical planar space and increase the sensitivity of the overall array. A particular case of the concept is implemented to decrease H-field destructive interferences in planar concentric in-phase arrays. An increase in signal to noise ratio of approximately 20% was achieved with two resonators placed over approximately the same planar area compared to common approaches at a target depth of 10 cm at 3 Tesla. Improved parallel imaging performance of this configuration is also demonstrated. The concept can be further used to increase coil density.

  8. 3-Tesla magnetic resonance imaging evaluation of posterior tibial tendon dysfunction with relevance to clinical staging.

    PubMed

    Chhabra, Avneesh; Soldatos, Theodoros; Chalian, Majid; Faridian-Aragh, Neda; Fritz, Jan; Fayad, Laura M; Carrino, John A; Schon, Lew

    2011-01-01

    The posterior tibial tendon (PTT) is the most important dynamic stabilizer of the medial ankle and longitudinal arch of the foot. PTT dysfunction is a degenerative disorder of the tendon, which secondarily involves multiple ligaments, joint capsules, fascia, articulations, and bony structures of the ankle, hindfoot, midfoot, and forefoot. When the tendon progressively attenuates, the patient develops a painful, progressive collapsed flatfoot or pes planovalgus deformity. This comprehensive review illustrates the 3-Tesla magnetic resonance imaging (3T MRI) features of PTT dysfunction. In addition, the reader will gain knowledge of the expected pathologic findings on MRI, as they are related to clinical staging of PTT dysfunction. Copyright © 2011 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  9. Evaluation by quantitative magnetic resonance imaging of trabecular bone quality in the dentate and edentulous mandible.

    PubMed

    Celenk, Cetin; Celenk, Peruze

    2008-01-01

    To quantify the differences in mandibular trabecular bone quality between edentulous and dentate patients using quantitative magnetic resonance imaging (QMRI). The patients in this study had been referred to our clinic for QMRI examination for various reasons. A total of 40 male patients (18 dentate, 22 edentulous), 45-55 years of age, were examined. Mandibular T2* axial cross-sections were performed following receipt of consent from each patient. T2* relaxation time values (RTVs) were determined in the trabecular area. The mean mandibular T2* RTVs of dentate and edentulous patients were 181 and 182, respectively. There were no significant differences between the two groups (P=0.929) (Student's t-test). Mandibular trabecular bone quality may not be influenced by edentulousness according to QMRI.

  10. Effects of sagittal endplate shape on lumbar segmental mobility as evaluated by kinetic magnetic resonance imaging.

    PubMed

    Li, Yawei; Lord, Elizabeth; Cohen, Yermie; Ruangchainikom, Monchai; Wang, Bing; Lv, Guohua; Wang, Jeffrey C

    2014-08-01

    Retrospective analysis using kinetic magnetic resonance imaging. To investigate relationships between vertebral endplate remodeling, Modic changes, disc degeneration, and lumbar segmental mobility. Previous studies have shown that disc degeneration and vertebral endplate Modic changes are associated with differences in spinal motion, however, the effects of vertebral endplate morphology on lumbar segmental motion have not been fully investigated. A total of 420 patients underwent kinetic magnetic resonance imaging of 2100 lumbar motion segments. Sagittal endplate shapes (concave, flat, irregular), Modic changes (types, 0-3), and disc degeneration (grade, I-V) were assessed along with translational and angular motion of vertebral segments in flexion, extension, and neutral positions. The most common findings were concave endplate shape (63.24%), type 2 Modic change (71.79%), and grade II disc degeneration (40.33%). Flat, irregular endplates were more common at L1-L2, L4-L5, and L5-S1 than L2-L3 and L3-L4. Types 1, 2, and 3 Modic changes increased in frequency according to endplate shape: concave less than flat less than irregular. Type 0 was observed to decrease with the change of endplate shape from flat to concave to irregular. Vertebral levels with irregular endplates had more disc generation than those with flat; levels with flat endplates had significantly more disc degeneration than those with concave. Translational motion of the lumbar segment was greatest at levels with irregular endplates and decreased at those with flat and then concaves endplates. Angular motion was least at levels with irregular endplates and increased at levels with flat, then concave endplates. The degree of pathogenic lumbar segmental motion is associated with remodeling of the sagittal endplate. Endplate remodeling may occur as an adaptation to restrain abnormal movement of the lumbar segment. N/A.

  11. Quantitative evaluation of susceptibility effects caused by dental materials in head magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Strocchi, S.; Ghielmi, M.; Basilico, F.; Macchi, A.; Novario, R.; Ferretti, R.; Binaghi, E.

    2016-03-01

    This work quantitatively evaluates the effects induced by susceptibility characteristics of materials commonly used in dental practice on the quality of head MR images in a clinical 1.5T device. The proposed evaluation procedure measures the image artifacts induced by susceptibility in MR images by providing an index consistent with the global degradation as perceived by the experts. Susceptibility artifacts were evaluated in a near-clinical setup, using a phantom with susceptibility and geometric characteristics similar to that of a human head. We tested different dentist materials, called PAL Keramit, Ti6Al4V-ELI, Keramit NP, ILOR F, Zirconia and used different clinical MR acquisition sequences, such as "classical" SE and fast, gradient, and diffusion sequences. The evaluation is designed as a matching process between reference and artifacts affected images recording the same scene. The extent of the degradation induced by susceptibility is then measured in terms of similarity with the corresponding reference image. The matching process involves a multimodal registration task and the use an adequate similarity index psychophysically validated, based on correlation coefficient. The proposed analyses are integrated within a computer-supported procedure that interactively guides the users in the different phases of the evaluation method. 2-Dimensional and 3-dimensional indexes are used for each material and each acquisition sequence. From these, we drew a ranking of the materials, averaging the results obtained. Zirconia and ILOR F appear to be the best choice from the susceptibility artefacts point of view, followed, in order, by PAL Keramit, Ti6Al4V-ELI and Keramit NP.

  12. Is clinical evaluation alone sufficient for the diagnosis of a Bankart lesion without the use of magnetic resonance imaging?

    PubMed

    Loh, Bryan; Lim, Jason Beng Teck; Tan, Andrew Hwee Chye

    2016-11-01

    Imaging modalities such as magnetic resonance arthrogram (MRA) offer great utility in diagnosing Bankart lesions but they are associated with a high degree of intra and interobserver variability. This study aims to evaluate the diagnostic accuracy of clinical evaluation and imaging modalities in Bankart lesions such as magnetic resonance imaging (MRI) and MRA of the shoulder. Between February 2004 to January 2015, a retrospectively review of the surgical records at a tertiary hospital identified a total of 250 patients treated with a shoulder arthroscopy for Bankart repair. All patients were thoroughly investigated preoperatively in which a detailed history were obtained, relevant physical examinations were performed (Load and Shift/Anterior Apprehension test) and pre-operative radiographs taken. Some patients subsequently underwent either an MRI or an MRA scan if the initial clinical evaluation was equivocal. Anterior Shoulder Apprehension test and the Load and Shift test identified 214 of 227 Bankart tears, with a sensitivity of 94% [95% confidence interval (CI), 90-97%]. MRI correctly identified 23 of 26 Bankart tears, with a sensitivity of 89% (95% CI, 70-98%). Out of the five superior labrum anterior-posterior (SLAP) tears identified on MRI, only three were confirmed during arthroscopic surgery. MRA correctly identified 84 of 89 Bankart tears, for a sensitivity of 94% (95% CI, 87-98%). In our study, we report that clinical evaluation with focused history-taking and anterior apprehension, load and shift clinical examination can diagnose anterior shoulder instability as reliably as MR imaging. For patients with equivocal clinical findings, MR imaging can aid in the diagnosis.

  13. Is clinical evaluation alone sufficient for the diagnosis of a Bankart lesion without the use of magnetic resonance imaging?

    PubMed Central

    Lim, Jason Beng Teck; Tan, Andrew Hwee Chye

    2016-01-01

    Background Imaging modalities such as magnetic resonance arthrogram (MRA) offer great utility in diagnosing Bankart lesions but they are associated with a high degree of intra and interobserver variability. This study aims to evaluate the diagnostic accuracy of clinical evaluation and imaging modalities in Bankart lesions such as magnetic resonance imaging (MRI) and MRA of the shoulder. Methods Between February 2004 to January 2015, a retrospectively review of the surgical records at a tertiary hospital identified a total of 250 patients treated with a shoulder arthroscopy for Bankart repair. All patients were thoroughly investigated preoperatively in which a detailed history were obtained, relevant physical examinations were performed (Load and Shift/Anterior Apprehension test) and pre-operative radiographs taken. Some patients subsequently underwent either an MRI or an MRA scan if the initial clinical evaluation was equivocal. Results Anterior Shoulder Apprehension test and the Load and Shift test identified 214 of 227 Bankart tears, with a sensitivity of 94% [95% confidence interval (CI), 90–97%]. MRI correctly identified 23 of 26 Bankart tears, with a sensitivity of 89% (95% CI, 70–98%). Out of the five superior labrum anterior-posterior (SLAP) tears identified on MRI, only three were confirmed during arthroscopic surgery. MRA correctly identified 84 of 89 Bankart tears, for a sensitivity of 94% (95% CI, 87–98%). Conclusions In our study, we report that clinical evaluation with focused history-taking and anterior apprehension, load and shift clinical examination can diagnose anterior shoulder instability as reliably as MR imaging. For patients with equivocal clinical findings, MR imaging can aid in the diagnosis. PMID:27942510

  14. Endometrium evaluation with high-field (3-Tesla) magnetic resonance imaging in patients submitted to uterine leiomyoma embolization

    PubMed Central

    Jacobs, Monica Amadio Piazza; Nasser, Felipe; Zlotnik, Eduardo; Messina, Marcos de Lorenzo; Baroni, Ronaldo Hueb

    2013-01-01

    ABSTRACT Objective: To evaluate the endometrial alterations related to embolization of uterine arteries for the treatment of symptomatic uterine leiomyomatosis (pelvic pain and/or uterine bleeding) by means of high-field (3-Tesla) magnetic resonance. Methods: This is a longitudinal and prospective study that included 94 patients with a clinical and imaging diagnosis of symptomatic uterine leiomyomatosis, all of them treated by embolization of the uterine arteries. The patients were submitted to evaluations by high-field magnetic resonance of the pelvis before and 6 months after the procedure. Specific evaluations were made of the endometrium on the T2-weighted sequences, and on the T1-weighted sequences before and after the intravenous dynamic infusion of the paramagnetic contrast. In face of these measures, statistical analyses were performed using Student's t test for comparison of the results obtained before and after the procedure. Results: An average increase of 20.9% was noted in the endometrial signal on T2-weighted images obtained after the uterine artery embolization procedure when compared to the pre-procedure evaluation (p=0.0004). In the images obtained with the intravenous infusion of paramagnetic contrast, an average increase of 18.7% was noted in the post-embolization intensity of the endometrial signal, compared to the pre-embolization measure (p<0.035). Conclusion: After embolization of the uterine arteries, there was a significant increase of the endometrial signal on the T2-weighted images and on the post-contrast images, inferring possible edema and increased endometrial flow. Future studies are needed to assess the clinical impact of these findings. PMID:23579745

  15. Magnetic resonance imaging of the cryptorchid testis.

    PubMed

    Landa, H M; Gylys-Morin, V; Mattrey, R F; Krous, H F; Kaplan, G W; Packer, M G

    1987-01-01

    Magnetic resonance imaging was used to evaluate seven patients with undescended testes. In six patients the presence or absence of testicular tissue was predicted correctly prior to surgery. Spermatic cord structures, if present, were accurately visualized in all patients.

  16. Usefulness of quantitative peritumoural perfusion and proton spectroscopic magnetic resonance imaging evaluation in differentiating brain gliomas from solitary brain metastases.

    PubMed

    Sparacia, Gianvincenzo; Gadde, Judith A; Iaia, Alberto; Sparacia, Benedetta; Midiri, Massimo

    2016-06-01

    The purpose of our study was to evaluate whether peritumoural perfusion weighted and proton spectroscopic magnetic resonance imaging can be used in differentiating between primary gliomas and solitary metastases. Ten low-grade gliomas, eight high-grade gliomas and 10 metastases were prospectively evaluated with magnetic resonance imaging, dynamic susceptibility contrast enhanced perfusion imaging and single-voxel proton magnetic resonance spectroscopy before surgical resection or stereotactic biopsy. Maximal relative cerebral blood volume values were calculated drawing three regions of interest of 2 cm(2) in the non-enhancing peritumoural areas. Maximal relative cerebral blood volume values were normalised to that of contralateral normal-appearing white matter. Maximal choline/creatine ratios were calculated from three voxels of 10 cm(3) placed in the peritumoural areas defined as non-enhancing peritumoural white matter surrounding the tumour. The tumour grade presumed with these values was compared to histopathological grading. Differences in the study parameters between groups were assessed using the Mann-Whitney test. A receiver operating characteristic analysis was performed to determine cut-off values. A clear relative cerebral blood volume cut-off value of 1.88 was detected for differentiating low-grade gliomas from high-grade gliomas. A clear relative cerebral blood volume cut-off value of 1.20 was detected for differentiation of metastases from gliomas. The differences in the choline/creatine ratios in the peritumoural regions of high-grade gliomas and of solitary metastasis were statistically significant (P < 0.001) but a clear cut-off value was not found. Our preliminary data support the hypothesis that peritumoural perfusion-weighted imaging can assist in preoperative differentiation between a glioma and a solitary metastasis. © The Author(s) 2016.

  17. Evaluation of papillary muscle function using cardiovascular magnetic resonance imaging in mitral valve prolapse.

    PubMed

    Han, Yuchi; Peters, Dana C; Kissinger, Kraig V; Goddu, Beth; Yeon, Susan B; Manning, Warren J; Nezafat, Reza

    2010-07-15

    Abnormal traction and excursion of the papillary muscle (PM) can be observed in patients with mitral valve prolapse (MVP) and can adversely affect the electrophysiologic stability of the underlying myocardium. Cardiovascular magnetic resonance (CMR) techniques can directly measure the excursion and velocity of PM tips during ventricular systole. In addition, high-resolution late gadolinium enhancement (LGE) CMR imaging allows for visualization of the underlying potentially arrhythmogenic PM fibrosis substrate. We prospectively studied 16 patients with MVP and 9 healthy adult subjects using phase-contrast CMR and cine CMR to assess the PM velocity and excursion. LGE CMR was performed in 13 patients with MVP (81%). The peak PM systolic velocity and maximum PM excursion were significantly increased in those with MVP (12 +/- 5 vs 5 +/- 2 cm/s and 15 +/- 5 vs 2 +/- 3 mm, both p <0.001). Definite PM LGE was found in 6 patients (46%) but the finding did not correlate with PM velocity or excursion. In conclusion, functional CMR imaging demonstrated increased peak PM systolic velocity and excursion distance in patients with MVP. These parameters, however, did not relate to underlying PM fibrosis. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  18. [Clinical features and magnetic resonance imaging evaluation of encephalopathy in high-risk late preterm infants].

    PubMed

    Zhu, Yan; Zhang, Ke; Hu, Lan; Xiao, Mi-Li; Li, Zhi-Hua; Chen, Chao

    2017-05-01

    To investigate the risk factors, clinical features, and magnetic resonance imaging (MRI) changes of encephalopathy in high-risk late preterm infants. Head MRI scan was performed for late preterm infants with high-risk factors for brain injury who were hospitalized between January 2009 and December 2014. The risk factors, clinical features, and head MRI features of encephalopathy in late preterm infants were analyzed. A total of 1 007 late preterm infants underwent MRI scan, among whom 313 (31.1%) had imaging features in accordance with the features of encephalopathy of prematurity. Of all infants, 76.7% had white matter damage. There was no association between the development of encephalopathy and gestational age in late preterm infants, but the detection rate of encephalopathy gradually increased with the increasing birth weight (P<0.05). The logistic regression analysis showed that a history of resuscitation was an independent risk factor for encephalopathy of prematurity (P<0.01). Encephalopathy of prematurity is commonly seen in high-risk late preterm infants, especially white matter damage. A history of resuscitation is an independent risk factor for encephalopathy in late preterm infants.

  19. Design and Evaluation of a Novel Trifluorinated Imaging Agent for Assessment of Bile Acid Transport Using Fluorine Magnetic Resonance Imaging

    PubMed Central

    Vivian, Diana; Cheng, Kunrong; Khurana, Sandeep; Xu, Su; Dawson, Paul A.; Raufman, Jean-Pierre; Polli, James E.

    2014-01-01

    Previously, we developed a trifluorinated bile acid, CA-lys-TFA, with the objective of noninvasively assessing bile acid transport in vivo using 19F magnetic resonance imaging (MRI). CA-lys-TFA was successfully imaged in the mouse gallbladder, but was susceptible to deconjugation in vitro by choloylglycine hydrolase (CGH), a bacterial bile acid deconjugating enzyme found in the terminal ileum and colon. The objective of the present study was to develop a novel trifluorinated bile acid resistant to deconjugation by CGH. CA-sar-TFMA was designed, synthesized, and tested for in vitro transport properties, stability, imaging properties, and its ability to differentially accumulate in the gallbladders of normal mice, compared with mice with known impaired bile acid transport (deficient in the apical sodium-dependent bile acid transporter, ASBT). CA-sar-TFMA was a potent inhibitor and substrate of ASBT and the Na+/taurocholate cotransporting polypeptide. Stability was favorable in all conditions tested, including the presence of CGH. CA-sar-TFMA was successfully imaged and accumulated at 16.1-fold higher concentrations in gallbladders from wild-type mice compared with those from Asbt-deficient mice. Our results support the potential of using MRI with CA-sar-TFMA as a noninvasive method to assess bile acid transport in vivo. PMID:25196788

  20. Functional evaluation of extracardiac ventriculopulmonary conduits and of the right ventricle with magnetic resonance imaging and velocity mapping.

    PubMed

    Holmqvist, C; Oskarsson, G; Ståhlberg, F; Thilén, U; Björkhem, G; Laurin, S

    1999-03-15

    Extracardiac ventriculopulmonary conduits tend to deteriorate over time, developing both obstruction and regurgitation. In this prospective study, magnetic resonance imaging (MRI) was compared with Doppler echocardiography to determine whether MRI improves the noninvasive evaluation of conduit patients. Twenty-five patients (median age 10 years, range 2.5 to 32) were investigated 27 times with Doppler echocardiography and an MRI protocol with spin echo sequences for morphology, velocity mapping, and multislice gradient echo technique for right ventricular volume measuring. Cardiac catheterization data were available in 6 patients. Echocardiography could assess the morphology of the conduits in 6 patients, whereas MRI demonstrated all conduits efficiently. Doppler echocardiography could evaluate the occurrence of regurgitation in 18 patients and could quantify peak velocity in 20 of the patients. A technically adequate MRI velocity mapping was obtained in 25 patients. There was good agreement between MRI and Doppler echocardiography in establishing or not establishing regurgitation, but Doppler echocardiography was less reliable in evaluating the degree of regurgitation. The correlation between peak velocity determined with Doppler and magnetic resonance imaging was r = 0.63 [corrected]. Correlations between catheterization pressure gradients and noninvasive techniques were r = 0.97 for magnetic resonance imaging [corrected] versus catheterization, and r = 0.86 [corrected] for Doppler versus catheterization. MRI can provide complete information on the morphology and function of extracardiac ventriculopulmonary conduits, as well as of the right ventricle. If the results of MRI and echocardiography with Doppler are in agreement, heart catheterization and angiography can be avoided, even in patients considered for conduit replacement.

  1. Magnetic resonance imaging is superior to radiography in evaluating spinal cord trauma in three bald eagles (Haliaeetus leucocephalus).

    PubMed

    Stauber, Erik; Holmes, Shannon; DeGhetto, Darlene L; Finch, Nickol

    2007-09-01

    Three bald eagles (Haliaeetus leucocephalus) found along highways and unable to fly were presented for evaluation. All eagles exhibited sternal recumbency, as well as flaccid hind limb and tail paralysis. Vertebral column and spinal cord trauma were suspected as the cause. One bird died, whereas the remaining 2 birds were stabilized for diagnostic imaging studies. All 3 birds were evaluated by radiography and magnetic resonance imaging (MRI) for diagnosis and for prognosis in the live birds. Radiographic findings in all 3 birds were inconclusive, whereas MRI results showed extensive damage of the spinal cord and vertebral column, precluding functional recovery. The 2 surviving birds were euthanatized. In all birds, MRI assessments correlated well with necropsy and histopathologic findings.

  2. Evaluation of Marrow Perfusion in the Femoral Head by Dynamic Magnetic Resonance Imaging

    PubMed Central

    Tsukamoto, Hiroshi; Kang, Young S.; Jones, Lynne C.; Cova, Maria; Herold, Christian J.; McVeigh, Elliot; Hungerford, David S.; Zerhouni, Elias A.

    2007-01-01

    Rationale and Objectives There is a continuing need for a greater sensitivity of magnetic resonance imaging (MRI) in the diagnosis of avascular necrosis (AVN). Previously, it was demonstrated that a dynamic MRI method, with gadolinium-DTPA (Gd-DTPA) enhancement, can detect acute changes not seen on spin-echo images after arterial occlusion in a dog model. Because venous congestion appears to be a more directly relevant hemodynamic abnormality in a majority of clinical AVN cases, the authors extended the dynamic MRI technique to study changes in venous occlusion. Methods Dynamic MRI of the proximal femur was performed in five adult dogs before and after unilateral ligation of common iliac and lateral circumflex veins. Sixteen sequential gradient-recalled pulse sequence (GRASS) images (time resolution = 45 mseconds, echo time = 9 mseconds, flip angle = 65°) were obtained immediately after a bolus intravenous injection of 0.2 mmol/kg of Gd-DTPA. Simultaneous measurements of regional blood flow were made using the radioactive microsphere method. Results After venous ligation, there was a 25% to 45% decrease in the degree of enhancement compared with preligation values on the ligated side. The decrease in cumulative enhancement (integrated over the entire time course) was statistically significant. The occlusion technique was verified by confirming a statistically significant decrease in blood flow determined by the microsphere method. Conclusions Dynamic Gd-DTPA-enhanced fast MRI technique can detect acute changes in bone marrow perfusion due to venous occlusion. This technique may have applications in the early detection of nontraumatic AVN. PMID:1601616

  3. [Evaluation of the vocal tract during Japanese vowel production in myasthenia gravis using magnetic resonance imaging].

    PubMed

    Kinoshita, Yoshimasa; Yasukouchi, Hideoki; Tsuru, Eichi; Tanaka, Ryuji; Matsushima, Yasuyuki

    2004-10-01

    We report a 65-year-old Japanese female whose primary symptom of myasthenia gravis was related to rhinolalia aperta. The vocal tract during vowel production was evaluated using two-dimensional fast advanced spin echo (2D-FASE) MR images on supine and prone position. Before treatment, MRI on prone position demonstrated anterior shift of the palatine uvula and the tongue during Japanese "a", "u" and "o" production following the gravity, the former suggested the paresis of the sphenosalpingostaphylinus and elevator veli palatini muscle and the latter the paresis of the styloglossal and hypoglossal muscles. After treatment of steroid pulse and immune absorption, 2D-FASE images on prone position revealed the normalized configuration of the tongue and the soft palate during the Japanese five-vowel production. Kinetic MRI may be useful for evaluation of dynamics of the tongue and the soft palate.

  4. Factors associated with false-negative cardiovascular magnetic resonance perfusion studies: A Clinical evaluation of magnetic resonance imaging in coronary artery disease (CE-MARC) substudy.

    PubMed

    Kidambi, Ananth; Sourbron, Steven; Maredia, Neil; Motwani, Manish; Brown, Julia M; Nixon, Jane; Everett, Colin C; Plein, Sven; Greenwood, John P

    2016-03-01

    To examine factors associated with false-negative cardiovascular magnetic resonance (MR) perfusion studies within the large prospective Clinical Evaluation of MR imaging in Coronary artery disease (CE-MARC) study population. Myocardial perfusion MR has excellent diagnostic accuracy to detect coronary heart disease (CHD). However, causes of false-negative MR perfusion studies are not well understood. CE-MARC prospectively recruited patients with suspected CHD and mandated MR, myocardial perfusion scintigraphy, and invasive angiography. This subanalysis identified all patients with significant coronary stenosis by quantitative coronary angiography (QCA) and MR perfusion (1.5T, T1 -weighted gradient echo), using the original blinded image read. We explored patient and imaging characteristics related to false-negative or true-positive MR perfusion results, with reference to QCA. Multivariate regression analysis assessed the likelihood of false-negative MR perfusion according to four characteristics: poor image quality, triple-vessel disease, inadequate hemodynamic response to adenosine, and Duke jeopardy score (angiographic myocardium-at-risk score). In all, 265 (39%) patients had significant angiographic disease (mean age 62, 79% male). Thirty-five (5%) had false-negative and 230 (34%) true-positive MR perfusion. Poor MR perfusion image quality, triple-vessel disease, and inadequate hemodynamic response were similar between false-negative and true-positive groups (odds ratio, OR [95% confidence interval, CI]: 4.1 (0.82-21.0), P = 0.09; 1.2 (0.20-7.1), P = 0.85, and 1.6 (0.65-3.8), P = 0.31, respectively). Mean Duke jeopardy score was significantly lower in the false-negative group (2.6 ± 1.7 vs. 5.4 ± 3.0, OR 0.34 (0.21-0.53), P < 0.0001). False-negative cardiovascular MR perfusion studies are uncommon, and more common in patients with lower angiographic myocardium-at-risk. In CE-MARC, poor image quality, triple-vessel disease, and inadequate

  5. Evaluation of breast cancer chemotherapy efficacy with multifractal spectrum analysis of magnetic resonance image.

    PubMed

    Li, Li; Hu, Wen-yong; Liu, Li-zhi; Pang, Ya-chun; Shao, Yuan-zhi

    2014-01-01

    Multifractal spectrum analysis of dynamic contrast enhanced (DCE) breast MR images was used to establish a new quantitative analysis method for solid tumor blood perfusion and to explore its applicability in evaluating efficacy of breast cancer chemotherapy. Five randomly selected patients suffering from newly diagnosed malignant breast nodule lesions were enrolled in this study, and four of them were treated with neoadjuvant chemotherapy. Their DCE breast MR images were collected before and after treatment. Chemotherapeutic efficacy was analyzed using international response evaluation criteria for solid tumors (RECIST). Sandbox method for statistical number density was employed to measure and calculate multifractal spectra of DCE breast MR images with spatiotemporal characteristics. Multifractal spectral data of malignant lesions before and after chemotherapy were compared. Multifractal spectra of malignant lesions show an asymmetric bell-shape. Chemotherapy efficacy was assessed to be partial remission (PR) for three patients and their multifractal spectral width significantly increased after chemotherapy while to be stable disease (SD) for other patient and of her changed slightly. Multifractal spectral width correlates with blood-supply condition of tumor lesion before and after chemotherapy, providing a potential suitable characteristic parameter for evaluating chemotherapeutic efficacy quantitatively.

  6. Transoral decompression evaluated by cine-mode magnetic resonance imaging: a case of basilar impression accompanied by Chiari malformation.

    PubMed

    Tominaga, T; Koshu, K; Ogawa, A; Yoshimoto, T

    1991-06-01

    Cine-mode magnetic resonance imaging provides simultaneous images of cerebrospinal fluid flow dynamics. A patient with a basilar impression accompanied by a Chiari malformation and von Recklinghausen's disease who underwent transoral decompression is reported. Preoperative cine-mode magnetic resonance imaging visualized an associated obstruction of cerebrospinal fluid pulsatile flow at the level of the foramen magnum. Tonsilar herniation (Chiari I malformation) and hydrocephalus were also present. Postoperatively, the obstruction of cerebrospinal fluid flow was resolved concomitant with the correction of the cervicomedullary angulation. On the basis of observations made by magnetic resonance imaging, the surgical treatment of basilar impression accompanied by Chiari malformation is briefly discussed.

  7. Role of image fusion combining three-dimensional digital subtraction angiography with magnetic resonance imaging in evaluation of unruptured cerebral aneurysms.

    PubMed

    Suzuki, Hidenori; Shimizu, Shigetoshi; Maki, Hiroaki; Maeda, Masayuki; Sakaida, Hiroshi; Trousset, Yves; Taki, Waro

    2007-01-01

    The goal of this study was to evaluate the usefulness of a recently developed image fusion of three-dimensional digital subtraction angiography (3D DSA) and magnetic resonance (MR) images, DSA-MR fusion, in the pre-treatment assessment of cerebral aneurysm. Eighteen patients with 21 unruptured anterior or posterior circulation aneurysms underwent pre-treatment DSA-MR fusion. The authors independently assessed whether DSA-MR fusion images provided any useful additional information compared with analysing 3D DSA and MR images separately, and if this had an impact on the therapeutic decision-making of unruptured aneurysms. DSA-MR fusion images were obtained within 30 minutes for all patients. In 19 of 21 aneurysms, it provided the following additional information to the findings of 3D DSA, MR images or both: the passing course in the brain tissues of perforating arteries near or originating from an aneurysm, and/or the spatial relationship between an aneurysm and an oculomotor nerve. This information from DSA-MR fusion images was useful for diagnosis, therapeutic decision-making and the risk assessment associated with the treatment, as well as patient education regarding cerebral aneurysm. DSA-MR fusion images were useful for the pre-treatment evaluation of unruptured cerebral aneurysms as a supplement to DSA and MR images.

  8. Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement.

    PubMed

    Kebed, Kalie Y; Al Adham, Raed I; Bishu, Kalkidan; Askew, J Wells; Klarich, Kyle W; Araoz, Philip A; Foley, Thomas A; Glockner, James F; Nishimura, Rick A; Anavekar, Nandan S

    2014-09-01

    Apical hypertrophic cardiomyopathy (HC) is an uncommon variant of HC. We sought to characterize cardiac magnetic resonance imaging (MRI) findings among apical HC patients. This was a retrospective review of consecutive patients with a diagnosis of apical HC who underwent cardiac MRI examinations at the Mayo Clinic (Rochester, MN) from August 1999 to October 2011. Clinical and demographic data at the time of cardiac MRI study were abstracted. Cardiac MRI study and 2-dimensional echocardiograms performed within 6 months of the cardiac MRI were reviewed; 96 patients with apical HC underwent cardiac MRI examinations. LV end-diastolic and end-systolic volumes were 130.7 ± 39.1 ml and 44.2 ± 20.9 ml, respectively. Maximum LV thickness was 19 ± 5 mm. Hypertrophy extended beyond the apex into other segments in 57 (59.4%) patients. Obstructive physiology was seen in 12 (12.5%) and was more common in the mixed apical phenotype than the pure apical (19.3 vs 2.6%, p = 0.02). Apical pouches were noted in 39 (40.6%) patients. Late gadolinium enhancement (LGE) was present in 70 (74.5%) patients. LGE was associated with severe symptoms and increased maximal LV wall thickness. In conclusion, cardiac MRI is well suited for studying the apical form of HC because of difficulty imaging the cardiac apex with standard echocardiography. Cardiac MRI is uniquely suited to delineate the presence or absence of an apical pouch and abnormal myocardial LGE that may have implications in the natural history of apical HM. In particular, the presence of abnormal LGE is associated with clinical symptoms and increased wall thickness.

  9. Evaluation of Gastric Volumes: Comparison of 3-D Ultrasound and Magnetic Resonance Imaging.

    PubMed

    Buisman, Wijnand J; Mauritz, Femke A; Westerhuis, Wouter E; Gilja, Odd Helge; van der Zee, David C; van Herwaarden-Lindeboom, Maud Y A

    2016-07-01

    To investigate gastric accommodation, accurate measurements of gastric volumes are necessary. An excellent technique to measure gastric volumes is dynamic magnetic resonance imaging (MRI). Unfortunately, dynamic MRI is expensive and not always available. A new 3-D ultrasound (US) method using a matrix transducer was developed to measure gastric volumes. In this prospective study, 14 healthy volunteers underwent a dynamic MRI and a 3-D US. Gastric volumes were calculated with intra-gastric liquid content and total gastric volume. Mean postprandial liquid gastric content was 397 ± 96.5 mL. Mean volume difference was 1.0 mL with limits of agreement of -8.9 to 10.9 mL. When gastric air was taken into account, mean total gastric volume was 540 ± 115.4 mL SD. Mean volume difference was 2.3 mL with limits of agreement of -21.1 to 26.4 mL. The matrix 3-D US showed excellent agreement with dynamic MRI. Therefore matrix 3-D US is a reliable alternative to measure gastric volumes.

  10. Evaluation of Papillary Muscle Function Using Cardiovascular Magnetic Resonance Imaging in Mitral Valve Prolapse

    PubMed Central

    Han, Yuchi; Peters, Dana C.; Kissinger, Kraig V.; Goddu, Beth; Yeon, Susan B.; Manning, Warren J.; Nezafat, Reza

    2010-01-01

    Abnormal traction and excursion of the papillary muscle (PM) can be observed in patients with mitral valve prolapse (MVP), which may adversely affect the electrophysiological stability of the underlying myocardium. Cardiovascular magnetic resonance (CMR) techniques can directly measure the excursion and velocity of PM tips during ventricular systole. In addition, high resolution late gadolinium enhancement (LGE)-CMR allows for visualization of underlying potentially arrhythmogenic PM fibrosis substrate. We prospectively studied 16 MVP and 9 healthy adult subjects with PC-CMR and cine-CMR to assess PM velocity and excursion. LGE-CMR was performed in 13 (81%) MVP subjects. Peak PM systolic velocity and maximum PM excursion were significantly increased in MVP subjects (12 ± 5 cm/s vs. 5 ± 2 cm/s and 15 ± 5 mm vs. 2 ± 3 mm, both p < 0.001). Definite PM LGE was found in 6 (46%) patients, but did not correlate with PM velocity or excursion. In conclusion, functional CMR imaging demonstrated increased peak PM systolic velocity and excursion distance in MVP patients. These parameters, however, did not relate to underlying PM fibrosis. PMID:20599010

  11. The effects of eccentric velocity on activation of elbow flexors: evaluation by magnetic resonance imaging.

    PubMed

    Kulig, K; Powers, C M; Shellock, F G; Terk, M

    2001-02-01

    To compare magnetic resonance imaging (MRI) signal intensity changes in the primary elbow flexors during two isotonic exercise protocols varying in eccentric velocity and the ratio of eccentric to concentric activity. Twelve men performed two exercise protocols. The right and left arms were randomly assigned to one of two protocols that had the same workload (60% 1RM) and same total time of exercise (144 s) but differed in the velocity and ratio of eccentric to concentric activity (1:1 and 5:1 for the fast and slow protocols, respectively). MRI signal intensity changes were quantified pre- and post-exercises using an inversion recovery sequence with a 1.5T MRI system (TR = 2500 ms, TE = 90 ms, TI = 140 ms). Percent change in MRI signal intensity, rate of perceived exertion (RPE), and delayed onset muscle soreness (DOMS) were recorded and analyzed. The biceps brachii was found to be preferentially recruited during the fast protocol compared with the brachialis, whereas the brachialis was found to be preferentially recruited during the slow protocol (P < 0.05). The fast exercise protocol was perceived as being more strenuous (RPE = 8.3 +/- 2.1) than the slow (RPE = 5.4 +/- 1.5, P < 0.05) and produced DOMS in 58% of the tested subjects. These results suggest that agonists respond to various loading conditions nonhomogeneously. These findings may have implications with respect to exercise prescriptions for specific muscles.

  12. Flexion strength of the toes in the normal foot. An evaluation using magnetic resonance imaging.

    PubMed

    Green, S M; Briggs, P J

    2013-12-01

    Flexion of the toes may be active from muscle contraction or passive from the reversed windlass function of the plantar aponeurosis. The aim of this study was to estimate the flexion moments the muscles of the foot and long digital flexors may be capable of generating and compare these calculations with published data. Magnetic resonance images were used to measure the maximal cross-sectional area of the foot muscles and long digital flexors, along with the radius of curvature of the metatarsal heads. Using known physiological data the maximal flexion moments the muscles may be able to generate at the metatarsophalangeal (MTP) joints were calculated. The methodology overestimates muscle strength and flexion moments at the metatarsophalangeal joints. The calculated maximal flexion moment at the 1st MTP joint is 4.27-6.84 Nm, for the 2nd, 3rd and 4th MTP joints 3.06-4.91 Nm, and the 5th MTP joint 0.47-0.75 Nm. The flexion moments the muscles may generate at the MTP joints do not account for the flexion forces seen in normal walking. Given that maximal strength is not used in normal walking, we conclude that the reversed windlass mechanism of the plantar aponeurosis must be important in normal function of the toes.

  13. Dosimetric evaluation for exposure of patient to a z-gradient coil in magnetic resonance imaging

    SciTech Connect

    Lu Mai; Ueno, Shoogo

    2011-04-01

    In magnetic resonance imaging, time-varied gradient magnetic fields may stimulate nerves and muscles by inducing electric fields and currents in patients, which may potentially cause health problems. In this paper, a realistic z-gradient coil was numerically designed and the exposure level in a 3D real human man model was calculated by using the impedance method. It was found that the z-gradient coil produces a magnetic flux density (B-field) with two regions of good homogeneity along the coil length, separated by a very weak B-field in the middle of the coil. The spatially averaged B-field is 281 times greater than that of the International Commission on Non-Ionizing Radiation Protection's (ICNIRP) reference level. The 1-cm{sup 2}-averaged induced current density in the central nervous system is 87 times greater than that of the ICNIRP's basic restriction. The maximum current density in all of the body tissues is above the nerve stimulation threshold.

  14. Evaluation of peripheral blood basophil activation by means of surface plasmon resonance imaging.

    PubMed

    Yanase, Yuhki; Hiragun, Takaaki; Yanase, Tetsuji; Kawaguchi, Tomoko; Ishii, Kaori; Hide, Michihiro

    2012-02-15

    Basophil activation in response to antigen may represent specificities of type I allergy of individuals and their reactions in the body. We previously demonstrated that surface plasmon resonance (SPR) sensor could detect the activation of human basophils in response to antigens. In this study, we further developed a technique based on SPR imaging (SPRI) system to detect reactions of individual basophils isolated from human blood, and investigated the potential of this sensor as a tool for diagnosis of type I allergy. To detect the change of refractive index (RI) in individual basophils, human basophils were isolated by negative selection with antibodies conjugated with magnetic beads, fixed on a gold film with anti-basophil antibody and stimulated with various antigens under the measurement of SPRI. The sensor could detect the reactions of individual basophils in response to specific antigens as well as non-specific activators. Moreover, the sensor well allocated two spots of basophils on a sensor chip and detected individual reactions to antigen. Thus, the technique developed in this study can visualize the effect of various stimuli or inhibitors on basophils as change of intracellular RI distribution at the single cell level. In combination with a device to rapidly isolate basophils from peripheral blood, this technique may be a useful tool as a high throughput screening system in clinical diagnosis for type I allergy.

  15. Lobar intracerebral haematomas: Neuropathological and 7.0-tesla magnetic resonance imaging evaluation.

    PubMed

    De Reuck, Jacques; Cordonnier, Charlotte; Deramecourt, Vincent; Auger, Florent; Durieux, Nicolas; Leys, Didier; Pasquier, Florence; Maurage, Claude-Alain; Bordet, Regis

    2016-10-15

    The Boston criteria for cerebral amyloid angiopathy (CAA) need validation by neuropathological examination in patients with lobar cerebral haematomas (LCHs). In "vivo" 1.5-tesla magnetic resonance imaging (MRI) is unreliable to detect the age-related signal changes in LCHs. This post-mortem study investigates the validity of the Boston criteria in brains with LCHs and the signal changes during their time course with 7.0-tesla MRI. Seventeen CAA brains including 26 LCHs were compared to 13 non-CAA brains with 14 LCHs. The evolution of the signal changes with time was examined in 25 LCHs with T2 and T2* 7.0-tesla MRI. In the CAA group LCHs were predominantly located in the parieto-occipital lobes. Also white matter changes were more severe with more cortical microinfarcts and cortical microbleeds. On MRI there was a progressive shift of the intensity of the hyposignal from the haematoma core in the acute stage to the boundaries later on. During the residual stage the hyposignal mildly decreased in the boundaries with an increase of the superficial siderosis and haematoma core collapse. Our post-mortem study of LCHs confirms the validity of the Boston criteria for CAA. Also 7.0-tesla MRI allows staging the age of the LCHs. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Optimising magnetic resonance imaging-based evaluation of the ossification of the medial clavicular epiphysis: a multi-centre study.

    PubMed

    Schmidt, S; Henke, C A; Wittschieber, D; Vieth, V; Bajanowski, T; Ramsthaler, F; Püschel, K; Pfeiffer, H; Schmeling, A; Schulz, R

    2016-11-01

    Evaluation of the ossification of the medial clavicular epiphysis plays a key role in forensic age estimation, particularly in determining whether the age of 18 has been attained. A key research objective in the forensic age estimation field at present is to establish non-X-ray methods for investigating the clavicle. This paper looks at the use of magnetic resonance imaging for evaluating the developmental state of the medial clavicular epiphysis. Clavicle specimens obtained from autopsies of 125 female and 270 male subjects aged from 10 to 30 were examined using a 3-T magnetic resonance scanner. One FFE-3D-T1 gradient echo sequence and one 2D-T2 turbo spin echo sequence were acquired. In each case, two investigators undertook a consensual determination of the ossification stage of the medial clavicular epiphysis using recognised classification systems. To determine intra-observer and inter-observer agreement, 80 clavicle specimens were subjected to repeat evaluation. We present statistics relating to the ossification stages. The inclusion of established sub-stages of clavicular ossification offers an additional option for determining whether a subject has attained the age of 18 which is applicable in both sexes. For both sexes, the minimum ages for ossification stages 4 and 5 allow conclusions to be drawn about a subject's age at a point in time lying several years in the past. Magnetic resonance imaging is a valid investigatory procedure for determining the ossification stage of the medial clavicular epiphysis. This paper makes a contribution to expanding the range of methods available for forensic age estimation.

  17. Inter- and intraobserver variability in the postoperative evaluation of transpedicular stabilization: computed tomography versus magnetic resonance imaging.

    PubMed

    Tohtz, Stephan W; Rogalla, Patrick; Taupitz, Matthias; Perka, Carsten; Winkler, Tobias; Putzier, Michael

    2010-04-01

    Computed tomography (CT) represents the state of the art for the postoperative verification of the implant position after transpedicular stabilizations. Magnetic resonance imaging (MRI) has not challenged the CT, yet, because of susceptibility artifacts but would be favorable as a diagnostic tool for its excellent soft-tissue qualities. A study that analyzed if an artifact-reduced MRI could overcome this problem and provide sufficient data for the postoperative assessment was conducted. The study design was a radiologic comparison of CT and MRI techniques evaluating pedicle screw placement after spinal fusion. Fifty consecutive patients were given an MRI and a CT after a transpedicular stabilization surgery. Thirty-eight patients suffered from degenerative spinal disorders; three surgeries had become necessary because of spondylodiscitis, eight patients suffered from metastatic vertebrae destruction, and one patient experienced a fracture. Any contact of a malpositioned pedicle screw with the dura and/or radicular structures was identified as an implant-associated complication and was compared with postoperative clinical patient findings. In total, 338 pedicular screws were analyzed in regard to their intrapedicular position. The double-blind evaluation of MRI and CT data was carried out by two radiologists and two spine surgeons. Accuracy of the CT analysis was calculated based on the interobserver agreement of 100%. Magnetic resonance imaging accuracy was calculated. The interobserver accuracy of the CT data amounted to a median of 89.8% and in the MRI data of 86.7%. Intraobserver comparisons showed a significant difference between CT and magnetic resonance evaluations in one observer (kappa=0.293). In all other observers, the results were concordant with kappa values from kappa=0.328 to kappa=0.702. There was a high degree of agreement regarding the diagnosis of malpositioned pedicle screw and corresponding clinical symptoms between both techniques. The

  18. Functional magnetic resonance imaging.

    PubMed

    Buchbinder, Bradley R

    2016-01-01

    Functional magnetic resonance imaging (fMRI) maps the spatiotemporal distribution of neural activity in the brain under varying cognitive conditions. Since its inception in 1991, blood oxygen level-dependent (BOLD) fMRI has rapidly become a vital methodology in basic and applied neuroscience research. In the clinical realm, it has become an established tool for presurgical functional brain mapping. This chapter has three principal aims. First, we review key physiologic, biophysical, and methodologic principles that underlie BOLD fMRI, regardless of its particular area of application. These principles inform a nuanced interpretation of the BOLD fMRI signal, along with its neurophysiologic significance and pitfalls. Second, we illustrate the clinical application of task-based fMRI to presurgical motor, language, and memory mapping in patients with lesions near eloquent brain areas. Integration of BOLD fMRI and diffusion tensor white-matter tractography provides a road map for presurgical planning and intraoperative navigation that helps to maximize the extent of lesion resection while minimizing the risk of postoperative neurologic deficits. Finally, we highlight several basic principles of resting-state fMRI and its emerging translational clinical applications. Resting-state fMRI represents an important paradigm shift, focusing attention on functional connectivity within intrinsic cognitive networks.

  19. Plain magnetic resonance imaging as an alternative in evaluating inflammation and bowel damage in inflammatory bowel disease--a prospective comparison with conventional magnetic resonance follow-through.

    PubMed

    Jesuratnam-Nielsen, Kayalvily; Løgager, Vibeke B; Rezanavaz-Gheshlagh, Bijan; Munkholm, Pia; Thomsen, Henrik S

    2015-05-01

    To compare prospectively the diagnostic accuracy of magnetic resonance imaging (MRI) without use of contrast medium orally or intravenously (plain MRI) with magnetic resonance follow-through (MRFT) in patients with inflammatory bowel disease (IBD). Plain MRI was carried out in addition to MRFT, to which the patients were referred. All patients underwent both examinations on the same day. For the evaluation, the bowel was divided into nine segments. Two radiologists, blinded to clinical findings, evaluated bowel wall thickness, diffusion weighted imaging (DWI), and other inflammatory changes in each bowel segments. Further, hyperenhancement of the bowel was also evaluated in MRFT. A total of 100 patients (40 males and 60 females; median age: 38.5; range: 19-90) were enrolled; 44 with Crohn's disease (CD), 25 with ulcerative colitis (UC), 24 with IBD unclassified (IBD-U), and 7 had other diagnosis. Sensitivity, specificity, and accuracy in CD ranged 50-86%, 93-94%, and 91-92% for wall thickening and 49-82%, 85-93%, and 84-89% for DWI, respectively. Sensitivity, specificity, and accuracy in UC range 0-40%, 87-100%, and 80-100% for wall thickening and 0-52%, 83-94% and 76-92% for DWI, respectively. The κ values for bowel wall thickening, DWI, and mural hyperenhancement were detected with fair agreement (κ = 0.26-0.39) at both MRI examinations, whereas only bowel wall thickening in MRFT were detected with moderate agreement (κ = 0.47) Conclusion. Plain MRI cannot currently replace MRFT in the workup of patients with IBD. Further research on plain MRI is needed to improve the protocol.

  20. First-pass evaluation of myocardial output during dipyridamole stress using turbo-FLASH magnetic resonance imaging.

    PubMed

    Tello, R; Hartnell, G G; Hill, T C; Cerel, A; Finn, J P; Kamalesh, M; Cohen, M; Lewis, S

    1996-11-01

    This study evaluated the value of dynamically enhanced fast low-angle shot (FLASH) magnetic resonance (MR) imaging in measuring cardiac output with and without dipyridamole pharmacological stress. Ten subjects underwent rest and stress MR imaging. Rest images were acquired using electrocardiogram gated MR (turbo-FLASH: repetition time = 6 mseconds; echo time = 12 mseconds; flip angle = 12 degrees, inversion time = 100) 10 to 45 seconds after intravenous bolus of 0.04 mmol/kg gadolinium (Gd)-DTPA using a Siemens 1.0-tesla Magnetom SP. Stress was induced within the MR imaging scanner with 0.56 mg/kg dipyridamole over 4 minutes with stress MR images obtained after a second bolus of Gd-DTPA in exactly the same position and time intervals. Cardiac output was calculated with a least squares error analysis before and after dipyridamole stress for the left and right ventricles in all 10 patients, and comparison was made with cardiac output by Fick dilution technique during cardiac catheterization in seven patients. This MR analysis methodology shows reasonable correlation (r = 0.953) between left ventricular and right ventricular cardiac output with no effect on cardiac output during immediate dipyridamole stress. Fick dilution studies demonstrated a correlation of 0.96. Turbo-FLASH MR can demonstrate time-activity curves and cardiac output calculations consistent with theoretical predictions.

  1. Reliability measures of functional magnetic resonance imaging in a longitudinal evaluation of mild cognitive impairment.

    PubMed

    Zanto, Theodore P; Pa, Judy; Gazzaley, Adam

    2014-01-01

    As the aging population grows, it has become increasingly important to carefully characterize amnestic mild cognitive impairment (aMCI), a preclinical stage of Alzheimer's disease (AD). Functional magnetic resonance imaging (fMRI) is a valuable tool for monitoring disease progression in selectively vulnerable brain regions associated with AD neuropathology. However, the reliability of fMRI data in longitudinal studies of older adults with aMCI is largely unexplored. To address this, aMCI participants completed two visual working tasks, a Delayed-Recognition task and a One-Back task, on three separate scanning sessions over a three-month period. Test-retest reliability of the fMRI blood oxygen level dependent (BOLD) activity was assessed using an intraclass correlation (ICC) analysis approach. Results indicated that brain regions engaged during the task displayed greater reliability across sessions compared to regions that were not utilized by the task. During task-engagement, differential reliability scores were observed across the brain such that the frontal lobe, medial temporal lobe, and subcortical structures exhibited fair to moderate reliability (ICC=0.3-0.6), while temporal, parietal, and occipital regions exhibited moderate to good reliability (ICC=0.4-0.7). Additionally, reliability across brain regions was more stable when three fMRI sessions were used in the ICC calculation relative to two fMRI sessions. In conclusion, the fMRI BOLD signal is reliable across scanning sessions in this population and thus a useful tool for tracking longitudinal change in observational and interventional studies in aMCI.

  2. Extreme hip motion in professional ballet dancers: dynamic and morphological evaluation based on magnetic resonance imaging.

    PubMed

    Kolo, Frank C; Charbonnier, Caecilia; Pfirrmann, Christian W A; Duc, Sylvain R; Lubbeke, Anne; Duthon, Victoria B; Magnenat-Thalmann, Nadia; Hoffmeyer, Pierre; Menetrey, Jacques; Becker, Christoph D

    2013-05-01

    To determine the prevalence of femoroacetabular impingement (FAI) of the cam or pincer type based on magnetic resonance imaging (MRI) in a group of adult female professional ballet dancers, and to quantify, in vivo, the range of motion (ROM) and congruence of the hip joint in the splits position. Institutional review board approval and informed consent from each volunteer were obtained. Thirty symptomatic or asymptomatic adult female professional ballet dancers (59 hips) and 14 asymptomatic non-dancer adult women (28 hips, control group) were included in the present study. All subjects underwent MRI in the supine position, while, for the dancers, additional images were acquired in the splits position. Labral abnormalities, cartilage lesions, and osseous abnormalities of the acetabular rim were assessed at six positions around the acetabulum. A morphological analysis, consisting of the measurement of the α angle, acetabular depth, and acetabular version, was performed. For the dancers, ROM and congruency of the hip joint in the splits position were measured. Acetabular cartilage lesions greater than 5 mm were significantly more frequent in dancer's hips than in control hips (28.8 vs 7.1%, p = 0.026), and were mostly present at the superior position in dancers. Distribution of labral lesions between the dancers and the control group showed substantially more pronounced labral lesions at the superior, posterosuperior, and anterosuperior positions in dancers (54 lesions in 28 dancer's hips vs 10 lesions in 8 control hips). Herniation pits were found significantly more often (p = 0.002) in dancer's hips (n = 31, 52.5%), 25 of them being located in a superior position. A cam-type morphology was found for one dancer and a retroverted hip was noted for one control. Femoroacetabular subluxations were observed in the splits position (mean: 2.05 mm). The prevalence of typical FAI of the cam or pincer type was low in this selected population of professional ballet

  3. The Emerging Role of Cardiovascular Magnetic Resonance Imaging in the Evaluation of Metabolic Cardiomyopathies.

    PubMed

    Mavrogeni, S; Markousis-Mavrogenis, G; Markussis, V; Kolovou, G

    2015-08-01

    The aim of this review is to discuss the role of Cardiovascular Magnetic Resonance (CMR) in the diagnosis, risk stratification, and follow-up of metabolic cardiomyopathies. The classification of myocardial diseases, proposed by WHO/ISFC task force, distinguished specific cardiomyopathies, caused by metabolic disorders, into 4 types: 1) endocrine disorders, 2) storage or infiltration disorders (amyloidosis, hemochromatosis and familial storage disorders), 3) nutritional disorders (Kwashiorkor, beri-beri, obesity, and alcohol), and 4) diabetic heart. Thyroid disease, pheochromocytoma, and growth hormone excess or deficiency may contribute to usually reversible dilated cardiomyopathy. Glucogen storage diseases can be presented with myopathy, liver, and heart failure. Lysosomal storage diseases can provoke cardiac hypertrophy, mimicking hypertrophic cardiomyopathy and arrhythmias. Hereditary hemochromatosis, an inherited disorder of iron metabolism, leads to tissue iron overload in different organs, including the heart. Cardiac amyloidosis is the result of amyloid deposition in the heart, formed from breakdown of normal or abnormal proteins that leads to increased heart stiffness, restrictive cardiomyopathy, and heart failure. Finally, nutritional disturbances and metabolic diseases, such as Kwashiorkor, beri-beri, obesity, alcohol consumption, and diabetes mellitus may also lead to severe cardiac dysfunction. CMR, through its capability to reliably assess anatomy, function, inflammation, rest-stress myocardial perfusion, myocardial fibrosis, aortic distensibility, iron and/or fat deposition can serve as an excellent tool for early diagnosis of heart involvement, risk stratification, treatment evaluation, and long term follow-up of patients with metabolic cardiomyopathies. © Georg Thieme Verlag KG Stuttgart · New York.

  4. Is magnetic resonance imaging useful in early evaluation of women on neoadjuvant chemotherapy for locally advanced cervical cancer?

    PubMed

    Sala, P; Marchiolè, P; Cittadini, G; Valenzano Menada, M; Moioli, M; Mammoliti, S; Costantini, S

    2012-01-01

    To evaluate the accuracy of magnetic resonance imaging (MRI) in staging cervical tumors after neoadjuvant chemotherapy (NACT). 26 women, affected by locally advanced cervical cancer and triaged for surgery after NACT, were submitted to three cycles of neoadjuvant chemotherapy. All patients were submitted to MRI before and after NACT. We evaluated the MRI sensitivity and specificity in staging cervical tumors after chemotherapy, relating MRI findings after NACT with the pathological findings as the gold standard. In our series, MRI sensitivity was 58.8% and specificity was 66.7%. In our study MRI accuracy after NACT was lower than that of MRI used to stage patients with early cervical cancer scheduled for primary surgery, reported by the literature. MRI false negative cases are the major problem because of the delay in application of an effective therapy in non responders to NACT.

  5. Magnetic resonance imaging-based evaluation of ossification of the medial clavicular epiphysis in forensic age assessment.

    PubMed

    Schmidt, S; Ottow, C; Pfeiffer, H; Heindel, W; Vieth, V; Schmeling, A; Schulz, R

    2017-09-09

    Evaluation of the degree of ossification of the medial clavicular epiphysis plays a crucial role in determining with an adequate degree of probability whether legally relevant age boundaries after the age of 17 have been crossed. In view of the need to avoid unnecessary radiation exposure, establishing non-X-ray methods for investigating the clavicle has long been a key objective in forensic age assessment research. Based on magnetic resonance imaging examinations in a large sample of healthy subjects, the current study for the first time presents statistical measures which allow inferences to be drawn for forensic age assessment in both sexes. We undertook a prospective study of a reference sample of 334 female and 335 male German volunteers aged from 12 to 24 using a 3-T MRI scanner. A 3D FFE (fast field echo) T1-weighted sequence with fat saturation was acquired. To stage ossification of the medial clavicular epiphysis, we used the clavicular ossification staging systems described by Schmeling et al. and Kellinghaus et al. Ossification stage IIIc offers a means in both sexes of demonstrating that the age of 18 has been attained prior to complete ossification of the epiphyseal plate. In both sexes, if a subject has reached ossification stage IV, it can be stated that he or she has attained the age of 21. Magnetic resonance imaging is a valid diagnostic procedure for determining the ossification stage of the medial clavicular epiphysis.

  6. Is there a place for cardiovascular magnetic resonance imaging in the evaluation of cardiovascular involvement in rheumatic diseases?

    PubMed

    Mavrogeni, Sophie; Vassilopoulos, Dimitrios

    2011-12-01

    Cardiovascular magnetic resonance (CMR) is a noninvasive, nonradiating imaging technique, which provides novel information for the evaluation of cardiovascular diseases. Until now it has been successfully used for the evaluation of congenital and acquired heart diseases, cardiac tumors-mass, iron overload, and myocardial fibrosis detection. Recently, its diagnostic capabilities have been extended to the evaluation of myocardial inflammation and myocardial perfusion. Currently, it is considered the gold standard for the evaluation of volumes, mass, ejection fraction of atriums and ventricles, quantification of iron overload in different organs, detection and follow-up of myocardial inflammation, myocardial infarction and its complications, evaluation of the aorta, detection of anomalous coronary arteries, and ectatic or aneurysmatic coronary arteries. All the above applications and mainly the CMR ability to detect myocardial inflammation, perfusion defects, fibrosis, coronary and great arteries aneurysms make it a valuable tool for cardiovascular system assessment, commonly affected during the course of rheumatic diseases. The technique has been already successfully used in the evaluation of vasculitides, systemic lupus erythematosus, myositis, and scleroderma. However, further studies are needed to evaluate its usefulness as a diagnostic and monitoring tool of cardiovascular involvement in rheumatic patients.

  7. Evaluation of Neonatal Lung Volume Growth by Pulmonary Magnetic Resonance Imaging in Patients with Congenital Diaphragmatic Hernia.

    PubMed

    Schopper, Melissa A; Walkup, Laura L; Tkach, Jean A; Higano, Nara S; Lim, Foong Yen; Haberman, Beth; Woods, Jason C; Kingma, Paul S

    2017-09-01

    To evaluate postnatal lung volume in infants with congenital diaphragmatic hernia (CDH) and determine if a compensatory increase in lung volume occurs during the postnatal period. Using a novel pulmonary magnetic resonance imaging method for imaging neonatal lungs, the postnatal lung volumes in infants with CDH were determined and compared with prenatal lung volumes obtained via late gestation magnetic resonance imaging. Infants with left-sided CDH (2 mild, 9 moderate, and 1 severe) were evaluated. The total lung volume increased in all infants, with the contralateral lung increasing faster than the ipsilateral lung (mean ± SD: 4.9 ± 3.0 mL/week vs 3.4 ± 2.1 mL/week, P = .005). In contrast to prenatal studies, the volume of lungs of infants with more severe CDH grew faster than the lungs of infants with more mild CDH (Spearman's ρ=-0.086, P = .01). Although the contralateral lung volume grew faster in both mild and moderate groups, the majority of total lung volume growth in moderate CDH came from increased volume of the ipsilateral lung (42% of total lung volume increase in the moderate group vs 32% of total lung volume increase in the mild group, P = .09). Analysis of multiple clinical variables suggests that increased weight gain was associated with increased compensatory ipsilateral lung volume growth (ρ = 0.57, P = .05). These results suggest a potential for postnatal catch-up growth in infants with pulmonary hypoplasia and suggest that weight gain may increase the volume growth of the more severely affected lung. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Coronary computed tomography and magnetic resonance imaging.

    PubMed

    Kantor, Birgit; Nagel, Eike; Schoenhagen, Paul; Barkhausen, Jörg; Gerber, Thomas C

    2009-04-01

    Cardiac computed tomography and magnetic resonance are relatively new imaging modalities that can exceed the ability of established imaging modalities to detect present pathology or predict patient outcomes. Coronary calcium scoring may be useful in asymptomatic patients at intermediate risk. Computed tomographic coronary angiography is a first-line indication to evaluate congenitally abnormal coronary arteries and, along with stress magnetic resonance myocardial perfusion imaging, is useful in symptomatic patients with nondiagnostic conventional stress tests. Cardiac magnetic resonance is indicated for visualizing cardiac structure and function, and delayed enhancement magnetic resonance is a first-line indication for assessing myocardial viability. Imaging plaque and molecular mechanisms related to plaque rupture holds great promise for the presymptomatic detection of patients at risk for coronary events but is not yet suitable for routine clinical use.

  9. Coronary Computed Tomography and Magnetic Resonance Imaging

    PubMed Central

    Kantor, Birgit; Nagel, Eike; Schoenhagen, Paul; Barkhausen, Jörg; Gerber, Thomas C.

    2009-01-01

    Cardiac computed tomography and magnetic resonance are relatively new imaging modalities that can exceed the ability of established imaging modalities to detect present pathology or predict patient outcomes. Coronary calcium scoring may be useful in asymptomatic patients at intermediate risk. Computed tomographic coronary angiography is a first-line indication to evaluate congenitally abnormal coronary arteries and, along with stress magnetic resonance myocardial perfusion imaging, is useful in symptomatic patients with nondiagnostic conventional stress tests. Cardiac magnetic resonance is indicated for visualizing cardiac structure and function, and delayed enhancement magnetic resonance is a first-line indication for assessing myocardial viability. Imaging plaque and molecular mechanisms related to plaque rupture holds great promise for the presymptomatic detection of patients at risk for coronary events but is not yet suitable for routine clinical use. PMID:19269527

  10. Evaluation of Renal Blood Flow and Oxygenation in CKD Using Magnetic Resonance Imaging.

    PubMed

    Khatir, Dinah S; Pedersen, Michael; Jespersen, Bente; Buus, Niels H

    2015-09-01

    Animal studies suggest that progression of chronic kidney disease (CKD) is related to renal hypoxia. With renal blood supply determining oxygen delivery and sodium absorption being the main contributor to oxygen consumption, we describe the relationship between renal oxygenation, renal artery blood flow, and sodium absorption in patients with CKD and healthy controls. Cross-sectional study. 62 stable patients with CKD stages 3 to 4 (mean age, 61±13 [SD] years) and 24 age- and sex-matched controls. CKD versus control status. Renal artery blood flow, tissue oxygenation (relative changes in deoxyhemoglobin concentration of the renal medulla [MR2*] and cortex [CR2*]), and sodium absorption. Renal artery blood flow was determined by phase-contrast magnetic resonance imaging (MRI); MR2* and CR2* were determined by blood oxygen level-dependent MRI. Ultrafiltered and reabsorbed sodium were determined from measured glomerular filtration rate (mGFR) and 24-hour urine collections. mGFR in patients was 37% that of controls (36±15 vs 97±23 mL/min/1.73 m(2); P < 0.001), and reabsorbed sodium was 37% that of controls (6.9 vs 19.1 mol/24 h; P < 0.001). Single-kidney patient renal artery blood flow was 72% that of controls (319 vs 443 mL/min; P < 0.001). Glomerular filtration fraction was 9% in patients and 18% in controls (P < 0.001). Patients and controls had similar CR2* (13.4 vs 13.3 s(-1)) and medullary MR2* (26.4 vs 26.5 s(-1)) values. Linear regression analysis demonstrated no associations between R2* and renal artery blood flow or sodium absorption. Increasing arterial blood oxygen tension by breathing 100% oxygen had very small effects on CR2*, but reduced MR2* in both groups. Only renal artery blood flow was determined and thus regional perfusion could not be related to CR2* or MR2*. In CKD, reductions of mGFR and reabsorbed sodium are more than double that of renal artery blood flow, whereas cortical and medullary oxygenation are within the range of healthy persons

  11. Evaluation of Epidural and Peripheral Nerve Catheter Heating During Magnetic Resonance Imaging

    PubMed Central

    Owens, Sean; Erturk, M. Arcan; Ouanes, Jean-Pierre P.; Murphy, Jamie D.; Wu, Christopher L.; Bottomley, Paul A.

    2014-01-01

    Background Many epidural and peripheral nerve catheters contain conducting wire that could heat during magnetic resonance imaging (MRI), requiring removal for scanning. Methods We tested 2 each of 6 brands of regional analgesia catheters (from Arrow International, B. Braun Medical, and Smiths Medical/Portex) for exposure to clinical 1.5 and 3 Tesla (T) MRI. Catheters testing as non-magnetic were placed in an epidural configuration in a standard human torso-sized phantom, and an MRI pulse sequence applied at the maximum scanner-allowed radio frequency (RF) specific absorption rate (SAR) for 15 minutes Temperature and SAR exposure were sampled during MRI using multiple fiber-optic temperature sensors. Results Two catheters (the Arrow StimuCath Peripheral Nerve, and Braun Medical Perifix FX Epidural) were found to be magnetic and not tested further. At 3T, exposure of the remaining 3 epidural and 1 peripheral nerve catheter to the scanner’s maximum RF exposure, elicited anomalous heating of 4 to 7°C in 2 Arrow Epidural (MultiPort and Flex-Tip Plus) catheters at the entry points. Temperature increases for the other catheters at 3T and all catheters at 1.5T were ≤1.4°C. When normalized to the body-average FDA guideline SAR of 4W/kg, maximum projected temperature increases were 0.1 to 2.5°C at 1.5T and 0.7 to 2.7°C at 3T, except for the Arrow MultiPort Flex-Tip Plus catheter at 3T whose increase was 14°C. Conclusions Most but not all catheters can be left in place during 1.5T MRI scans. Heating of <3°C during MRI for most catheters is not expected to be injurious. While heating was lower at 1.5T vs 3T, performance differences between products underscore the need for safety testing before performing MRI. PMID:25275576

  12. Magnetic Resonance Imaging (MRI) Safety

    MedlinePlus

    ... Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) Safety What is MRI and how does ... the area being scanned include: Metallic spinal rod Plates, pins, screws, or metal mesh used to repair ...

  13. Advances in breast imaging: magnetic resonance imaging.

    PubMed

    Bartella, Lia; Morris, Elizabeth A

    2006-01-01

    Magnetic resonance imaging (MRI) of the breast is rapidly becoming incorporated into clinical practice. Indications for breast MRI include staging of known breast cancer, monitoring response to chemotherapy, assessing recurrence, problem solving, and high-risk screening. Magnetic resonance spectroscopy is a promising technique that may decrease the number of benign biopsies generated by breast MRI in the clinical setting.

  14. Detection and Evaluation of Renal Injury in Burst Wave Lithotripsy Using Ultrasound and Magnetic Resonance Imaging.

    PubMed

    May, Philip C; Kreider, Wayne; Maxwell, Adam D; Wang, Yak-Nam; Cunitz, Bryan W; Blomgren, Philip M; Johnson, Cynthia D; Park, Joshua S H; Bailey, Michael R; Lee, Donghoon; Harper, Jonathan D; Sorensen, Mathew D

    2017-08-01

    Burst wave lithotripsy (BWL) is a transcutaneous technique with potential to safely and effectively fragment renal stones. Preclinical investigations of BWL require the assessment of potential renal injury. This study evaluates the capabilities of real-time ultrasound and MRI to detect and evaluate BWL injury that was induced in porcine kidneys. Ten kidneys from five female farm pigs were treated with either a 170 or 335 kHz BWL transducer using variable treatment parameters and monitored in real-time with ultrasound. Eight kidneys were perfusion fixed and scanned with a 3-Tesla MRI scanner (T1-weighted, T2-weighted, and susceptibility-weighted imaging), followed by processing via an established histomorphometric technique for injury quantification. In addition, two kidneys were separately evaluated for histologic characterization of injury quality. Observed B-mode hyperechoes on ultrasound consistent with cavitation predicted the presence of BWL-induced renal injury with a sensitivity and specificity of 100% in comparison to the histomorphometric technique. Similarly, MRI detected renal injury with a sensitivity of 90% and specificity of 100% and was able to identify the scale of lesion volumes. The injuries purposefully generated with BWL were histologically similar to those formed by shock wave lithotripsy. BWL-induced renal injury can be detected with a high degree of sensitivity and specificity by real-time ultrasound and post-treatment ex vivo MRI. No injury occurred in this study without cavitation detected on ultrasound. Such capabilities for injury detection and lesion volume quantification on MRI can be used for preclinical testing of BWL.

  15. Utilizing magnetic resonance imaging logs, openhole logs, and sidewall core analyses to evaluate shaly sands for water-free production

    SciTech Connect

    Taylor, D.A.; Morganti, J.K.; White, H.J. ); Noblett, B.R. )

    1996-01-01

    Nuclear magnetic resonance (NMR) logging using the new C Series Magnetic Resonance Imaging Log (MRIL) system is rapidly enhancing formation evaluation throughout the industry. By measuring irreducible water saturations, permeabilities, and effective porosities, MRIL data can help petrophysicists evaluate low-resistivity pays. In these environments, conventional openhole logs may not define all of the pay intervals. The MRIL system can also reduce the number of unnecessary completions in zones of potentially high water cut. MRIL tool theory and log presentations used with conventional logs and sidewall cores are presented along with field examples. Scanning electron microscope (SEM) analysis shows good correlation of varying grain size in sandstones with the T2 distribution and bulk volume irreducible water determined from the MRIL measurements. Analysis of each new well drilled in the study area shows how water-free production zones were defined. Because the MRIL data were not recorded on one of the wells, predictions from the conventional logs and the MRIL data collected on the other two wells were used to estimate productive zones in the first well. Discussion of additional formation characteristics, completion procedures, actual production, and predicted producibility of the shaly sands is presented. Integrated methodologies resulted in the perforation of 3 new wells for a gross initial potential of 690 BOPD and 0 BWPD.

  16. Utilizing magnetic resonance imaging logs, openhole logs, and sidewall core analyses to evaluate shaly sands for water-free production

    SciTech Connect

    Taylor, D.A.; Morganti, J.K.; White, H.J.; Noblett, B.R.

    1996-12-31

    Nuclear magnetic resonance (NMR) logging using the new C Series Magnetic Resonance Imaging Log (MRIL) system is rapidly enhancing formation evaluation throughout the industry. By measuring irreducible water saturations, permeabilities, and effective porosities, MRIL data can help petrophysicists evaluate low-resistivity pays. In these environments, conventional openhole logs may not define all of the pay intervals. The MRIL system can also reduce the number of unnecessary completions in zones of potentially high water cut. MRIL tool theory and log presentations used with conventional logs and sidewall cores are presented along with field examples. Scanning electron microscope (SEM) analysis shows good correlation of varying grain size in sandstones with the T2 distribution and bulk volume irreducible water determined from the MRIL measurements. Analysis of each new well drilled in the study area shows how water-free production zones were defined. Because the MRIL data were not recorded on one of the wells, predictions from the conventional logs and the MRIL data collected on the other two wells were used to estimate productive zones in the first well. Discussion of additional formation characteristics, completion procedures, actual production, and predicted producibility of the shaly sands is presented. Integrated methodologies resulted in the perforation of 3 new wells for a gross initial potential of 690 BOPD and 0 BWPD.

  17. A comparison of magnetic resonance imaging with electrodiagnostic findings in the evaluation of clinical radiculopathy: a cross-sectional study.

    PubMed

    Reza Soltani, Zahra; Sajadi, Simin; Tavana, Behrooz

    2014-04-01

    The aim of this study was to evaluate the agreement of magnetic resonance imaging and electrodiagnostic studies by comparing their findings in patients with clinically suspected radiculopathy. The agreements between these two procedures and clinical findings were also examined. In a 2-year cross-sectional study, a total of 114 patients with clinically suspected cervical or lumbosacral radiculopathy were included. The total agreements between clinical with MRI and EDX findings were 72 and 52%, respectively while their agreements were similar in group definite (89 vs. 82%). The agreement between EDX and MRI was 59.6 in total and 49% with respect to clinical findings. This study further supports that these two methods are complementary in general. It is reasonable to add EDX when there is discrepancy between MRI and clinical findings or when MRI neurologic findings are not visible.

  18. Detection and Evaluation of Early Breast Cancer via Magnetic Resonance Imaging: Studies of Mouse Models and Clinical Implementation

    DTIC Science & Technology

    2007-03-01

    5 Feb 2007 4 . TITLE AND SUBTITLE 5a. CONTRACT NUMBER Detection and Evaluation of Early Breast Cancer via Magnetic Resonance Imaging: Studies of...Page Introduction…………………………………………………………….………..….. 4 Body………………………………………………………………………………….. 5 Key Research Accomplishments...11 Appendices…………………………………………………………………………… 12 4 INTRODUCTION Women diagnosed with breast cancer today have significantly better

  19. Adalimumab markedly improves enthesitis in patients with psoriatic arthritis: Evaluation with a magnetic resonance imaging scoring system.

    PubMed

    Yanaba, Koichi; Sadaoka, Akari; Yonenaga, Takenori; Saeki, Hidehisa; Umezawa, Yoshinori; Tojo, Shinjiro; Ito, Toshihiro; Kikuchi, Sota; Fukuda, Kunihiko; Nakagawa, Hidemi

    2015-12-01

    Psoriatic arthritis (PsA), a seronegative arthropathy, may often result in progressive joint damage without treatment, leading to disability and impaired quality of life. Early therapeutic intervention of PsA is therefore crucial before the development of irreversible joint damage. Because psoriatic skin lesions generally precede the onset of PsA, dermatologists occupy an important position in treating patients with early PsA. This study aimed to evaluate the efficacy of adalimumab in treating joint disease in patients with PsA, using the PsA magnetic resonance imaging scoring system (PsAMRIS). Five adult Japanese male patients with active PsA were treated with adalimumab. Magnetic resonance imaging was obtained at baseline and 8-32 weeks with 2-3 time points following adalimumab treatment and assessed using PsAMRIS. Adalimumab treatment markedly improved clinical symptoms and disease activities of joint disease, which was confirmed by the reduction of PsAMRIS scores in all patients. Bone marrow edema and periarticular inflammation, reflecting the presence of enthesitis, were dramatically improved at week 8, while improvement of synovitis and flexor tenosynovitis was observed later, at week 24 or 32. However, bone erosion was not improved by adalimumab treatment during the follow-up period. These results indicate that adalimumab treatment is associated with dramatic improvement of enthesitis in patients with PsA, whereas bone erosion may be resistant to such treatment. PsAMRIS appears to be useful for the evaluation of treatment efficacy in PsA.

  20. Evaluation of magnetic resonance imaging issues for a wirelessly powered lead used for epidural, spinal cord stimulation.

    PubMed

    Shellock, Frank G; Audet-Griffin, Annabelle J

    2014-06-01

    The objective of this investigation was to evaluate magnetic resonance imaging (MRI) issues (magnetic field interactions, MRI-related heating, and artifacts) for a wirelessly powered lead used for spinal cord stimulation (SCS). A newly developed, wirelessly powered lead (Freedom-4, Stimwave Technologies Inc., Scottsdale, AZ, USA) underwent evaluation for magnetic field interactions (translational attraction and torque) at 3 Tesla, MRI-related heating at 1.5 Tesla/64 MHz and 3 Tesla/128 MHz, and artifacts at 3 Tesla using standardized techniques. MRI-related heating tests were conducted by placing the lead in a gelled-saline-filled phantom and performing MRI procedures using relatively high levels of radiofrequency energy. Artifacts were characterized using T1-weighted, spin echo (SE), and gradient echo (GRE) pulse sequences. The lead exhibited minor magnetic field interactions (2 degree deflection angle and no torque). Heating was not substantial under 1.5 Tesla/64 MHz (highest temperature change, 2.3°C) and 3 Tesla/128 MHz (highest temperature change, 2.2°C) MRI conditions. Artifacts were moderate in size relative to the size and shape of the lead. These findings demonstrated that it is acceptable for a patient with this wirelessly powered lead used for SCS to undergo MRI under the conditions utilized in this investigation and according to other necessary guidelines. Artifacts seen on magnetic resonance images may pose possible problems if the area of interest is in the same area or close to this lead. © 2013 International Neuromodulation Society.

  1. Preclinical evaluation of biodegradable macromolecular contrast agents for magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Feng, Yi

    Macromolecular contrast agents have been shown to be superior to small molecular weight contrast agents for MRI in blood pool imaging, tumor diagnosis and grading. However, none has been approved by the FDA because they circulate in the bloodstream much longer than small molecular weight contrast agents and result in high tissue accumulation of toxic Gd(III) ions. Biodegradable macromolecular contrast agents (BMCA) were invented to alleviate the toxic accumulation. They have a cleavable disulfide bond based backbone that can be degraded in vivo and excreted out of the body via renal filtration. Furthermore, the side chain of the backbone can be modified to achieve various degradation rates. Three BMCA, (Gd-DTPA)-cystamine copolymers (GDCC), Gd-DTPA cystine copolymers (GDCP), and Gd-DTPA cystine diethyl ester copolymers (GDCEP), were evaluated as blood pool contrast agents in a rat model. They have excellent blood pool enhancement, preferred pharmacokinetics, and only minimal long-term tissue retention of toxic Gd(III) ions. GDCC and GDCP, the lead agents with desired degradation rates, with molecular weights of 20 KDa and 70 KDa, were chosen for dynamic contrast enhanced MRI (DCE-MRI) to differentiate human prostate tumor models of different malignancy and growth rates. GDCC and GDCP could differentiate these tumor models, providing more accurate estimations of plasma volume, flow leakage rate, and permeability surface area product than a small molecular weight contrast agent Gd-DTPA-BMA when compared to the prototype macromolecular contrast agent albumin-Gd-DTPA. GDCC was favored for its neutral charge side chain and reasonable uptake rate by the tumors. GDCC with a molecular weight of 40 KDa (GDCC-40, above the renal filtration cutoff size) was used to assess the efficacy of two photothermal therapies (interstitial and indocyanine green enhanced). GDCC-40 provided excellent tumor enhancement shortly after its injection. Acute tumor response (4 hr) after therapies

  2. Magnetic resonance imaging of the cirrhotic liver: diagnosis of hepatocellular carcinoma and evaluation of response to treatment - Part 1

    PubMed Central

    Ramalho, Miguel; Matos, António P.; AlObaidy, Mamdoh; Velloni, Fernanda; Altun, Ersan; Semelka, Richard C.

    2017-01-01

    Magnetic resonance imaging (MRI) is the modern gold standard for the noninvasive evaluation of the cirrhotic liver. The combination of arterial phase hyperenhancement and delayed wash-out allows a definitive diagnosis of hepatocellular carcinoma (HCC) in patients with liver cirrhosis or chronic liver disease, without the requirement for confirmatory biopsy. That pattern is highly specific and has been endorsed in Western and Asian diagnostic guidelines. However, the sensitivity of the combination is relatively low for small HCCs. In this two-part review paper, we will address MRI of the cirrhotic liver. In this first part, we provide a brief background on liver cirrhosis and HCC, followed by descriptions of imaging surveillance of liver cirrhosis and the diagnostic performance of the different imaging modalities used in clinical settings. We then describe some of the requirements for the basic MRI technique, as well as the standard MRI protocol, and provide a detailed description of the appearance of various types of hepatocellular nodules encountered in the setting of the carcinogenic pathway in the cirrhotic liver, ranging from regenerative nodules to HCC. PMID:28298731

  3. Evaluation of Neoadjuvant Chemotherapy Response with Dynamic Contrast Enhanced Breast Magnetic Resonance Imaging in Locally Advanced Invasive Breast Cancer

    PubMed Central

    Gezer, Naciye Sinem; Orbay, Özge; Balcı, Pınar; Durak, Merih Guray; Demirkan, Binnaz; Saydam, Serdar

    2014-01-01

    Objective The reliability of traditional methods such as physical examination, ultrasonography (US) and mammography is limited in determining the type of treatment response in patients with neoadjuvant chemotherapy (NAC) application for locally advanced breast cancer (LABC). Dynamic contrast-enhanced magnetic resonance imaging (MRI) is gaining popularity in the evaluation of NAC response. This study aimed to compare NAC response as determined by dynamic contrast-enhanced breast MRI in patients with LABC to histopathology that is the gold standard; and evaluate the compatibility of MRI, mammography and US with response types. Materials and Methods The US, mammography and MRI findings of 38 patients who received NAC with a diagnosis of locally advanced breast cancer and surgical treatment were retrospectively analyzed and compared to histopathology results. Type of response to treatment was determined according to the “Criteria in Solid Tumors Response Evolution 1.1” by mammography, US and MRI criteria. The relationship between response types as defined by all three imaging modalities and histopathology were evaluated, and the correlation of response type as detected by MRI and pathological response and histopathological type of breast cancer was further determined. For statistical analysis, the chi-square, paired t test, correlation and kappa tests were used. Results There is a statistical moderate positive correlation between response type according to pathology and MRI (kappa: 0.63). There was a weak correlation between response type according to mammography or US and according to pathology (kappa: 0.2). When the distribution of treatment response by MRI is stratified according to histopathological types, partial response was higher in all histopathological types similar to the type of pathologic response. When compared with pathology MRI detected treatment response accurately in 84.2% of the patients. Conclusion Dynamic contrast-enhanced breast MRI appears to

  4. Acute oedema in the evaluation of microvascular reperfusion and myocardial salvage in reperfused myocardial infarction with cardiac magnetic resonance imaging.

    PubMed

    Phrommintikul, Arintaya; Abdel-Aty, Hassan; Schulz-Menger, Jeanette; Friedrich, Matthias G; Taylor, Andrew J

    2010-06-01

    The accurate measurement of myocardial salvage is critical to the ongoing refinement of reperfusion strategies in acute myocardial infarction (AMI). Cardiac magnetic resonance imaging (CMR) can define the area at risk in AMI by the presence of myocardial oedema, identified by high signal intensity on T(2)-weighted imaging with a short inversion time inversion-recovery (STIR) sequence. In addition, myocardial necrosis can be identified with CMR delayed contrast enhanced imaging. In this prospective study we examined the relationship of acute oedema and necrosis with impaired microvascular reperfusion. We also evaluated acute oedema as a marker of the area at risk in AMI, for the purposes of documenting myocardial salvage. CMR was performed on 15 patients with (AMI), within 24h of successful percutaneous coronary intervention (PCI). Left ventricular (LV) systolic dysfunction was defined by a systolic thickening <40% (severe <20%). Microvascular reperfusion was evaluated during the acute phase of contrast wash-in. CMR was repeated 3 months post-PCI to evaluate recovery of LV function and final infarct size. Myocardial salvage was defined as the percentage of the area at risk that was not infarcted on follow up CMR. There was a significant correlation between impaired microvascular reperfusion and the extent of segmental oedema (R=0.363, P<0.01), but not myocardial necrosis (R=0.110, P>0.5). The extent of myocardial salvage correlated with recovery of systolic function (R=0.241, P<0.05), which was strongest in LV segments with severely reduced systolic function (R=0.422, P<0.01). In acutely reperfused AMI, oedema can be used to identify the area at risk for the purpose of calculating myocardial salvage. The correlation between myocardial oedema and reperfusion status suggests a pathological role of acute oedema in the impairment of microvascular reperfusion. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  5. Evaluation of Soft Tissue Sarcoma Response to Preoperative Chemoradiotherapy Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

    PubMed Central

    Huang, Wei; Beckett, Brooke R.; Tudorica, Alina; Meyer, Janelle M.; Afzal, Aneela; Chen, Yiyi; Mansoor, Atiya; Hayden, James B.; Doung, Yee-Cheen; Hung, Arthur Y.; Holtorf, Megan L.; Aston, Torrie J.; Ryan, Christopher W.

    2016-01-01

    This study aims to assess the utility of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters in comparison with imaging tumor size for early prediction and evaluation of soft tissue sarcoma response to preoperative chemoradiotherapy. In total, 20 patients with intermediate- to high-grade soft tissue sarcomas received either a phase I trial regimen of sorafenib + chemoradiotherapy (n = 8) or chemoradiotherapy only (n = 12), and underwent DCE-MRI at baseline, after 2 weeks of treatment with sorafenib or after the first chemotherapy cycle, and after therapy completion. MRI tumor size in the longest diameter (LD) was measured according to the RECIST (Response Evaluation Criteria In Solid Tumors) guidelines. Pharmacokinetic analyses of DCE-MRI data were performed using the Shutter-Speed model. After only 2 weeks of treatment with sorafenib or after 1 chemotherapy cycle, Ktrans (rate constant for plasma/interstitium contrast agent transfer) and its percent change were good early predictors of optimal versus suboptimal pathological response with univariate logistic regression C statistics values of 0.90 and 0.80, respectively, whereas RECIST LD percent change was only a fair predictor (C = 0.72). Post-therapy Ktrans, ve (extravascular and extracellular volume fraction), and kep (intravasation rate constant), not RECIST LD, were excellent (C > 0.90) markers of therapy response. Several DCE-MRI parameters before, during, and after therapy showed significant (P < .05) correlations with percent necrosis of resected tumor specimens. In conclusion, absolute values and percent changes of quantitative DCE-MRI parameters provide better early prediction and evaluation of the pathological response of soft tissue sarcoma to preoperative chemoradiotherapy than the conventional measurement of imaging tumor size change. PMID:28066805

  6. Clinical Evaluation and Magnetic Resonance Imaging Assessment of Intradiscal Methylene Blue Injection for the Treatment of Discogenic Low Back Pain.

    PubMed

    Zhang, XiaoJun; Hao, Jie; Hu, Zhenming; Yang, HaiTao

    2016-01-01

    Low back pain is a common worldwide health problem and has a significant socioeconomic impact on public health. Internal disc disruption has been considered as the most common cause of low back pain. Various therapies, including interbody fusion, disc replacement, injection therapies, and thermal annular procedures have been utilized for the treatment of discogenic low back pain. Recently, a new method of intradiscal methylene blue injection has been introduced to treat discogenic low back pain, but the clinical outcomes are controversial. To investigate the clinical outcomes and magnetic resonance imaging changes of intradiscal methylene blue injection for the treatment of discogenic low back pain. Observational study. An interventional low back pain management practice in a university hospital. A total of 33 patients were selected to be treated with intradiscal methylene blue injection. The clinical outcomes were evaluated by numeric rating scale and Oswestry Disability Index at pretreatment, one month, 3, 6, and 12 months after treatment. The magnetic resonance imaging changes of involved intervertebral discs were assessed by apparent diffusion coefficient and T2 values at pretreatment, 3, 6, and 12 months after treatment. All of the patients got a follow-up period up to 12 months. The mean numeric rating scale scores at pretreatment, one month, 3, 6, and 12 months after treatment were 6.54, 2.98, 3.23, 3.66, and 4.72, respectively. There was a minimum of 2 points reduction at one month, 3, and 6 months after treatment, but less than 2 points reduction at 12 months. There was at least 50% improvement on the Oswestry Disability Index at one month, 3, and 6 months after treatment, but not at 12 months. The mean apparent diffusion coefficient and T2 value were significantly higher at 6 and12 months after treatment compared to pretreatment, but there was no significant difference between pretreatment and 3 months after treatment. This is an observational study with

  7. Optically detected magnetic resonance imaging

    SciTech Connect

    Blank, Aharon; Shapiro, Guy; Fischer, Ran; London, Paz; Gershoni, David

    2015-01-19

    Optically detected magnetic resonance provides ultrasensitive means to detect and image a small number of electron and nuclear spins, down to the single spin level with nanoscale resolution. Despite the significant recent progress in this field, it has never been combined with the power of pulsed magnetic resonance imaging techniques. Here, we demonstrate how these two methodologies can be integrated using short pulsed magnetic field gradients to spatially encode the sample. This result in what we denote as an 'optically detected magnetic resonance imaging' technique. It offers the advantage that the image is acquired in parallel from all parts of the sample, with well-defined three-dimensional point-spread function, and without any loss of spectroscopic information. In addition, this approach may be used in the future for parallel but yet spatially selective efficient addressing and manipulation of the spins in the sample. Such capabilities are of fundamental importance in the field of quantum spin-based devices and sensors.

  8. Advances in Magnetic Resonance Imaging

    NASA Astrophysics Data System (ADS)

    Price, R. R.

    1996-05-01

    Nuclear Magnetic Resonance (NMR) Imaging, now more commonly referred to as Magnetic Resonance Imaging (MRI), developed into an important clinical modality between the years of 1978 and 1985. In 1945 it was demonstrated independently by Bloch(F. Bloch, The Principle of Nuclear Induction, Nobel Lectures in Physics: 1946-1962 New York, Elsevier Science Publishing Co., Inc. 1964.) and Purcell(E.M. Purcell, Research in Nuclear Magnetism, Nobel Lectures in Physics: 1946-1962, New York. Elsevier Science Publishing Co., Inc. 1964.) that magnetic nuclei in a sample when placed in a static magnetic field exhibit a characteristic resonance frequency which is proportional to the field strength and unique to nuclei of the same type and same environment. The net magnetization of the sample when irradiated by an RF wave at the resonance frequency could thus be manipulated to produce an induced "NMR signal" in a conducting loop placed near the sample. In the early 1970's, methods were developed whereby the NMR signal could be spatially encoded in both frequency and phase by means of superimposed linear magnetic field gradients to produce NMR images. NMR image contrast is a function of nuclear concentration and magnetic relaxation times (T1 and T2). MRI became the first medical imaging modality to provide both high resolution and high contrast images of soft tissue. Current clinical MRI systems produce images of the distribution of ^1H nuclei (primarily water) within the body. Other biologically important nuclei (^13C, ^23N, ^31P), as well as the imaging of hyperpolarized inert gases (^3He, ^129Xe) are under investigation. Recent developments in ^1H-MRI have included chemical shift imaging (hydrogen containing metabolites), blood flow imaging (MR angiography), ultra high-speed imaging (Echo Planar), and imaging of brain function based upon magnetic susceptibility differences resulting from blood oxygenation changes during brain activity.

  9. Dissociations between behavioural and functional magnetic resonance imaging-based evaluations of cognitive function after brain injury

    PubMed Central

    Bardin, Jonathan C.; Fins, Joseph J.; Katz, Douglas I.; Hersh, Jennifer; Heier, Linda A.; Tabelow, Karsten; Dyke, Jonathan P.; Ballon, Douglas J.; Schiff, Nicholas D.

    2011-01-01

    Functional neuroimaging methods hold promise for the identification of cognitive function and communication capacity in some severely brain-injured patients who may not retain sufficient motor function to demonstrate their abilities. We studied seven severely brain-injured patients and a control group of 14 subjects using a novel hierarchical functional magnetic resonance imaging assessment utilizing mental imagery responses. Whereas the control group showed consistent and accurate (for communication) blood-oxygen-level-dependent responses without exception, the brain-injured subjects showed a wide variation in the correlation of blood-oxygen-level-dependent responses and overt behavioural responses. Specifically, the brain-injured subjects dissociated bedside and functional magnetic resonance imaging-based command following and communication capabilities. These observations reveal significant challenges in developing validated functional magnetic resonance imaging-based methods for clinical use and raise interesting questions about underlying brain function assayed using these methods in brain-injured subjects. PMID:21354974

  10. Dissociations between behavioural and functional magnetic resonance imaging-based evaluations of cognitive function after brain injury.

    PubMed

    Bardin, Jonathan C; Fins, Joseph J; Katz, Douglas I; Hersh, Jennifer; Heier, Linda A; Tabelow, Karsten; Dyke, Jonathan P; Ballon, Douglas J; Schiff, Nicholas D; Voss, Henning U

    2011-03-01

    Functional neuroimaging methods hold promise for the identification of cognitive function and communication capacity in some severely brain-injured patients who may not retain sufficient motor function to demonstrate their abilities. We studied seven severely brain-injured patients and a control group of 14 subjects using a novel hierarchical functional magnetic resonance imaging assessment utilizing mental imagery responses. Whereas the control group showed consistent and accurate (for communication) blood-oxygen-level-dependent responses without exception, the brain-injured subjects showed a wide variation in the correlation of blood-oxygen-level-dependent responses and overt behavioural responses. Specifically, the brain-injured subjects dissociated bedside and functional magnetic resonance imaging-based command following and communication capabilities. These observations reveal significant challenges in developing validated functional magnetic resonance imaging-based methods for clinical use and raise interesting questions about underlying brain function assayed using these methods in brain-injured subjects.

  11. Evaluation of encephalic ventricular volume from the magnetic resonance imaging scans of thirty-eight human subjects.

    PubMed

    Cramer, G D; Allen, D J; DiDio, L J; Potvin, W; Brinker, R

    1990-01-01

    Accurate volume determination of the encephalic ventricles is of importance in several clinical conditions, including Alzheimer's presenile dementia, schizophrenia, and benign intracranial hypertension. Previous studies have investigated the accuracy with which magnetic resonance imaging (MRI) can be used in clinical practice to evaluate the encephalic ventricles. However, adequate evaluation of pathological conditions depends on a sufficient amount of morphometric data from normal subjects. To begin establishing this data base for "normal" subjects, we evaluated the MRI scans of 38 subjects found to have no apparent pathology and calculated the ventricular volume in each case by using methods previously developed in our laboratory. The results were then compared with published volumes determined from studies that used either ventricular casts or computerized tomographic scans. The average total ventricular volume for all 38 subjects was 17.4 cm3, while that for males was 16.3 cm3 and that for females was 18.0 cm3. A small but significant correlation was found between age of subject and ventricular volume, with ventricular size increasing with age.

  12. Can glenoid wear be accurately assessed using x-ray imaging? Evaluating agreement of x-ray and magnetic resonance imaging (MRI) Walch classification.

    PubMed

    Kopka, Michaela; Fourman, Mitchell; Soni, Ashish; Cordle, Andrew C; Lin, Albert

    2017-09-01

    The Walch classification is the most recognized means of assessing glenoid wear in preoperative planning for shoulder arthroplasty. This classification relies on advanced imaging, which is more expensive and less practical than plain radiographs. The purpose of this study was to determine whether the Walch classification could be accurately applied to x-ray images compared with magnetic resonance imaging (MRI) as the gold standard. We hypothesized that x-ray images cannot adequately replace advanced imaging in the evaluation of glenoid wear. Preoperative axillary x-ray images and MRI scans of 50 patients assessed for shoulder arthroplasty were independently reviewed by 5 raters. Glenoid wear was individually classified according to the Walch classification using each imaging modality. The raters then collectively reviewed the MRI scans and assigned a consensus classification to serve as the gold standard. The κ coefficient was used to determine interobserver agreement for x-ray images and independent MRI reads, as well as the agreement between x-ray images and consensus MRI. The inter-rater agreement for x-ray images and MRIs was "moderate" (κ = 0.42 and κ = 0.47, respectively) for the 5-category Walch classification (A1, A2, B1, B2, C) and "moderate" (κ = 0.54 and κ = 0.59, respectively) for the 3-category Walch classification (A, B, C). The agreement between x-ray images and consensus MRI was much lower: "fair-to-moderate" (κ = 0.21-0.51) for the 5-category and "moderate" (κ = 0.36-0.60) for the 3-category Walch classification. The inter-rater agreement between x-ray images and consensus MRI is "fair-to-moderate." This is lower than the previously reported reliability of the Walch classification using computed tomography scans. Accordingly, x-ray images are inferior to advanced imaging when assessing glenoid wear. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights

  13. Evaluation of low back pain with low field open magnetic resonance imaging scanner in rural hospital of Southern India

    PubMed Central

    Shrinuvasan, Sadhanandham; Chidambaram, Ranganathan

    2016-01-01

    Background: Low back pain (LBP) is the most common symptom which is associated with limitation of normal activities and work-related disability. Imaging techniques are often essential in making the correct diagnosis for prompt management. Plain Radiography though remain a first imaging modality, magnetic resonance imaging (MRI) due to its inherent softtissue contrast resolution and lack of ionizing radiation remains invaluable modality in the evaluation of LBP. Aim: To find the common causes of LBP in different age groups and the role of MRI in detecting the spectrum of various pathological findings. Materials and Methods: This is a prospective study done in the Department of Radiodiagnosis during a period of 2 years from July 2013 to July 2015. The study population includes all the cases referred to our department with complaints of LBP. Patients with ferromagnetic metallic implants and uncooperative cases were excluded. HITACHI 0.4 Tesla open MRI machine was used for imaging. Results and Conclusion: This study involved a total of 235 cases. There were 121 males and 114 females. The age of the patient ranged from 21 to 68 years with an average of 41.3 years. Back pain was commonly observed in the third to fifth decade. The common causes for back pain are disc herniations (disc bulge – 35.3%, disc protrusion – 39.6%, disc extrusion – 7.2%) accounting to 82.1%, followed by normal study (10.2%), vertebral collapse (traumatic – 2.1%, osteoporotic – 1.7%), infections (2.1%), and neoplasm (1.7%). MRI provides valuable information regarding the underlying causes of LBP, especially in disc and marrow pathology. PMID:27365953

  14. The role of magnetic resonance imaging in the evaluation of transfusional iron overload in myelodysplastic syndromes

    PubMed Central

    Petrou, Emmanouil; Mavrogeni, Sophie; Karali, Vasiliki; Kolovou, Genovefa; Kyrtsonis, Marie-Christine; Sfikakis, Petros P.; Panayiotidis, Panayiotis

    2015-01-01

    Myelodysplastic syndromes represent a group of heterogeneous hematopoietic neoplasms derived from an abnormal multipotent progenitor cell, characterized by a hyperproliferative bone marrow, dysplasia of the cellular hemopoietic elements and ineffective erythropoiesis. Anemia is a common finding in myelodysplastic syndrome patients, and blood transfusions are the only therapeutic option in approximately 40% of cases. The most serious side effect of regular blood transfusion is iron overload. Currently, cardiovascular magnetic resonance using T2 is routinely used to identify patients with myocardial iron overload and to guide chelation therapy, tailored to prevent iron toxicity in the heart. This is a major validated non-invasive measure of myocardial iron overloading and is superior to surrogates such as serum ferritin, liver iron, ventricular ejection fraction and tissue Doppler parameters. The indication for iron chelation therapy in myelodysplastic syndrome patients is currently controversial. However, cardiovascular magnetic resonance may offer an excellent non-invasive, diagnostic tool for iron overload assessment in myelodysplastic syndromes. Further studies are needed to establish the precise indications of chelation therapy and the clinical implications of this treatment on survival in myelodysplastic syndromes. PMID:26190429

  15. Evaluation of Right Ventricular Systolic Function in Chagas Disease Using Cardiac Magnetic Resonance Imaging.

    PubMed

    Moreira, Henrique T; Volpe, Gustavo J; Marin-Neto, José A; Ambale-Venkatesh, Bharath; Nwabuo, Chike C; Trad, Henrique S; Romano, Minna M D; Pazin-Filho, Antonio; Maciel, Benedito C; Lima, João A C; Schmidt, André

    2017-03-01

    Right ventricular (RV) impairment is postulated to be responsible for prominent systemic congestion in Chagas disease. However, occurrence of primary RV dysfunction in Chagas disease remains controversial. We aimed to study RV systolic function in patients with Chagas disease using cardiac magnetic resonance. This cross-sectional study included 158 individuals with chronic Chagas disease who underwent cardiac magnetic resonance. RV systolic dysfunction was defined as reduced RV ejection fraction based on predefined cutoffs accounting for age and sex. Multivariable logistic regression was used to verify the relationship of RV systolic dysfunction with age, sex, functional class, use of medications for heart failure, atrial fibrillation, and left ventricular systolic dysfunction. Mean age was 54±13 years, 51.2% men. RV systolic dysfunction was identified in 58 (37%) individuals. Although usually associated with reduced left ventricular ejection fraction, isolated RV systolic dysfunction was found in 7 (4.4%) patients, 2 of them in early stages of Chagas disease. Presence of RV dysfunction was not significantly different in patients with indeterminate/digestive form of Chagas disease (35.7%) compared with those with Chagas cardiomyopathy (36.8%) (P=1.000). In chronic Chagas disease, RV systolic dysfunction is more commonly associated with left ventricular systolic dysfunction, although isolated and early RV dysfunction can also be identified. © 2017 American Heart Association, Inc.

  16. Application of a compact magnetic resonance imaging system for toxicologic pathology: evaluation of lithium-pilocarpine-induced rat brain lesions.

    PubMed

    Taketa, Yoshikazu; Shiotani, Motohiro; Tsuru, Yoshiharu; Kotani, Sadaharu; Osada, Yoshihide; Fukushima, Tatsuto; Inomata, Akira; Hosokawa, Satoru

    2015-10-01

    Magnetic resonance imaging (MRI) is a useful noninvasive tool used to detect lesions in clinical and veterinary medicine. The present study evaluated the suitability of a new easy-to-use compact MRI platform (M2 permanent magnet system, Aspect Imaging, Shoham, Israel) for assisting with preclinical toxicologic pathology examination of lesions in the rat brain. In order to induce brain lesions, male Sprague-Dawley rats were treated once with lithium chloride (127 mg/kg, intraperitoneal [i.p.]) followed by pilocarpine (30 mg/kg, i.p.). One week after dosing, the perfused, fixed brains were collected, analyzed by the MRI system and examined histopathologically. MRI of the brain of treated rats revealed areas of high T1 and middle to low T2 signals, when compared with the controls, in the piriform cortex, lateral thalamic nucleus, posterior paraventricular thalamic nucleus and posterior hypothalamic nucleus of the cerebrum. The altered MRI signal areas were consistent with well-circumscribed foci of neuronal cell degeneration/necrosis accompanied by glial cell proliferation. The present data demonstrated that quick analysis of fixed organs by the MRI system can detect the presence and location of toxicologic lesions and provide useful temporal information for selection of appropriate sections for histopathologic examination before routine slide preparation, especially in complex and functionally heterogeneous organs such as the brain.

  17. Evaluation of left ventricular scar identification from contrast enhanced magnetic resonance imaging for guidance of ventricular catheter ablation therapy

    NASA Astrophysics Data System (ADS)

    Rettmann, M. E.; Lehmann, H. I.; Johnson, S. B.; Packer, D. L.

    2016-03-01

    Patients with ventricular arrhythmias typically exhibit myocardial scarring, which is believed to be an important anatomic substrate for reentrant circuits, thereby making these regions a key target in catheter ablation therapy. In ablation therapy, a catheter is guided into the left ventricle and radiofrequency energy is delivered into the tissue to interrupt arrhythmic electrical pathways. Low bipolar voltage regions are typically localized during the procedure through point-by-point construction of an electroanatomic map by sampling the endocardial surface with the ablation catheter and are used as a surrogate for myocardial scar. This process is time consuming, requires significant skill, and has the potential to miss low voltage sites. This has led to efforts to quantify myocardial scar preoperatively using delayed, contrast-enhanced MRI. In this paper, we evaluate the utility of left ventricular scar identification from delayed contrast enhanced magnetic resonance imaging for guidance of catheter ablation of ventricular arrhythmias. Myocardial infarcts were created in three canines followed by a delayed, contrast enhanced MRI scan and electroanatomic mapping. The left ventricle and myocardial scar is segmented from preoperative MRI images and sampled points from the procedural electroanatomical map are registered to the segmented endocardial surface. Sampled points with low bipolar voltage points visually align with the segmented scar regions. This work demonstrates the potential utility of using preoperative delayed, enhanced MRI to identify myocardial scarring for guidance of ventricular catheter ablation therapy.

  18. Magnetic Resonance Imaging (MRI)

    MedlinePlus

    ... an image. Repeated exposure can be harmful.An MRI scan takes longer to perform (30 to 60 minutes, ... a treatment plan.Depending on your symptoms, an MRI will scan a specific portion of your body to diagnose: ...

  19. Quantitative magnetic resonance imaging evaluation of the olfactory system in Kallmann syndrome: correlation with a clinical smell test.

    PubMed

    Koenigkam-Santos, Marcel; Santos, Antonio Carlos; Versiani, Beatriz R; Diniz, Paula Rejane B; Junior, Jorge Elias; de Castro, Margaret

    2011-01-01

    To measure olfactory bulbs and sulci using dedicated magnetic resonance imaging (MRI) sequences and specific measurement tools in Kallmann syndrome (KS) patients with a well-established genotype and phenotype, as well as correlate MRI findings with a clinical smell test. MRI was performed in 21 patients with KS and 16 healthy volunteers; olfactory dysfunction was assessed using the Smell Identification Test (UPSIT), a qualitative suprathreshold olfaction test. Coronal turbo spin echo T2-weighted and volumetric T1-weighted gradient echo sequences were acquired in a 1.5T system. ImageJ software was used to obtain olfactory bulb volumes and olfactory sulcus depths and lengths. Data were analyzed with SPSS 15.0 and the Kappa index was used to evaluate the agreement between the UPSIT and MRI. The UPSIT showed 14 patients with anosmia and 6 with moderate hyposmia. Eighteen patients (85%) presented altered rhinencephalon structures in the MRI. Sixteen patients (76%) presented olfactory bulb aplasia (14/16 bilaterally), and these patients presented a total of 16 aplastic sulci. There was moderate agreement between the MRI quantitative evaluation and the UPSIT (overall Kappa = 0.55), but when considering the presence of aplastic bulbs and anosmia, we found almost perfect agreement (Kappa = 0.87). Three patients had normal rhinencephalon structures, including one with a KAL1 gene mutation. Olfactory bulb and sulcus aplasia were the most common findings in KS patients. We objectively demonstrated agreement between MRI findings and the smell test, especially the presence of bulb aplasia and anosmia. Therefore, our findings help ascertain MRI accuracy in the diagnosis of KS, differentiating patients with hypogonadotropic hypogonadism with an apparently normal or difficult to evaluate sense of smell. Copyright © 2011 S. Karger AG, Basel.

  20. Evaluation of Parkinson's disease by neuromelanin-sensitive magnetic resonance imaging and (123)I-FP-CIT SPECT.

    PubMed

    Kuya, Keita; Ogawa, Toshihide; Shinohara, Yuki; Ishibashi, Mana; Fujii, Shinya; Mukuda, Naoko; Tanabe, Yoshio

    2017-01-01

    Background Both neuromelanin-sensitive magnetic resonance imaging (NmMRI) and (123)I-FP-CIT single photon emission computed tomography (SPECT) (DaTSCAN) assist the diagnosis of Parkinson's disease (PD). However, there have been few studies investigating a correlation between them. Purpose To correlate the utility of NmMRI and DaTSCAN and to evaluate the relationship between both imaging findings and the Unified PD rating scale part III (UPDRS III) score for the diagnosis and management of PD. Material and Methods Seventeen patients with PD who underwent both NmMRI and DaTSCAN were included. We measured the volume of the neuromelanin-positive substantia nigra pars compacta (SNc volume) on NmMRI and measured the specific binding ratio (SBR) on DaTSCAN. The asymmetry index (AI) of the SNc volume and SBR were also calculated. We evaluated the relationship between the UPDRS III score and the SNc volume and SBR, respectively. Results The SNc volume showed a significant correlation with the SBR. The AIs of them also showed a significant correlation. Both the mean of the bilateral SBR and the mean of the bilateral SNc volume showed significant negative correlations with the UPDRS III score. However, the correlation between the SBR and the UPDRS III score was stronger than that between the SNc volume and the UPDRS III score. Conclusion Both NmMRI and DaTSCAN are helpful for PD diagnosis. However, we conclude that DaTSCAN is more suitable for the evaluation of the clinical motor severity and would be more useful for the management of PD patients than NmMRI.

  1. Quantitative comparison and evaluation of software packages for assessment of abdominal adipose tissue distribution by magnetic resonance imaging.

    PubMed

    Bonekamp, S; Ghosh, P; Crawford, S; Solga, S F; Horska, A; Brancati, F L; Diehl, A M; Smith, S; Clark, J M

    2008-01-01

    To examine five available software packages for the assessment of abdominal adipose tissue with magnetic resonance imaging, compare their features and assess the reliability of measurement results. Feature evaluation and test-retest reliability of softwares (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision) used in manual, semi-automated or automated segmentation of abdominal adipose tissue. A random sample of 15 obese adults with type 2 diabetes. Axial T1-weighted spin echo images centered at vertebral bodies of L2-L3 were acquired at 1.5 T. Five software packages were evaluated (NIHImage, SliceOmatic, Analyze, HippoFat and EasyVision), comparing manual, semi-automated and automated segmentation approaches. Images were segmented into cross-sectional area (CSA), and the areas of visceral (VAT) and subcutaneous adipose tissue (SAT). Ease of learning and use and the design of the graphical user interface (GUI) were rated. Intra-observer accuracy and agreement between the software packages were calculated using intra-class correlation. Intra-class correlation coefficient was used to obtain test-retest reliability. Three of the five evaluated programs offered a semi-automated technique to segment the images based on histogram values or a user-defined threshold. One software package allowed manual delineation only. One fully automated program demonstrated the drawbacks of uncritical automated processing. The semi-automated approaches reduced variability and measurement error, and improved reproducibility. There was no significant difference in the intra-observer agreement in SAT and CSA. The VAT measurements showed significantly lower test-retest reliability. There were some differences between the software packages in qualitative aspects, such as user friendliness. Four out of five packages provided essentially the same results with respect to the inter- and intra-rater reproducibility. Our results using SliceOmatic, Analyze or NIHImage were comparable and could

  2. Relationship between the medial elbow adduction moment during pitching and ulnar collateral ligament appearance during magnetic resonance imaging evaluation.

    PubMed

    Hurd, Wendy J; Kaufman, Kenton R; Murthy, Naveen S

    2011-06-01

    Medial elbow distraction during pitching as the primary mechanism contributing to adaptations in ulnar collateral ligament (UCL) appearance during magnetic resonance imaging (MRI) evaluation has not been established. Uninjured high school-aged pitchers with unilateral adaptations of the UCL exhibit a higher peak internal elbow adduction moment than those without UCL adaptations. Cohort study (Prevalence); Level of evidence, 2. Twenty uninjured, asymptomatic high school-aged pitchers underwent bilateral elbow MRI examinations. Three-dimensional motion analysis testing was performed to collect throwing arm biomechanics as participants pitched from an indoor mound. Nonparametric tests were performed to compare peak internal elbow adduction moment in uninjured participants with and without adaptations in UCL appearance and to determine the nature of the relationship between the peak internal adduction moment and UCL appearance. Uninjured participants with UCL thickening exhibited a higher peak internal elbow adduction moment of 53.3 ± 6.8 N·m compared with uninjured participants without adaptations in UCL appearance, 38.8 ± 10.9 N·m (P = .05), as higher moments were correlated with ligament thickening (correlation coefficient, 0.45) (P = .02). This study establishes the association between medial elbow distraction captured by the internal adduction moment during pitching and UCL adaptations visible during MRI evaluation.

  3. Relationship Between the Medial Elbow Adduction Moment During Pitching and Ulnar Collateral Ligament Appearance During Magnetic Resonance Imaging Evaluation

    PubMed Central

    Hurd, Wendy J.; Kaufman, Kenton R.; Murthy, Naveen S.

    2014-01-01

    Background Medial elbow distraction during pitching as the primary mechanism contributing to adaptations in ulnar collateral ligament (UCL) appearance during magnetic resonance imaging (MRI) evaluation has not been established. Hypothesis Uninjured high school–aged pitchers with unilateral adaptations of the UCL exhibit a higher peak internal elbow adduction moment than those without UCL adaptations. Study Design Cohort study (Prevalence); Level of evidence, 2. Methods Twenty uninjured, asymptomatic high school–aged pitchers underwent bilateral elbow MRI examinations. Three-dimensional motion analysis testing was performed to collect throwing arm biomechanics as participants pitched from an indoor mound. Nonparametric tests were performed to compare peak internal elbow adduction moment in uninjured participants with and without adaptations in UCL appearance and to determine the nature of the relationship between the peak internal adduction moment and UCL appearance. Results Uninjured participants with UCL thickening exhibited a higher peak internal elbow adduction moment of 53.3 ± 6.8 N·m compared with uninjured participants without adaptations in UCL appearance, 38.8 ± 10.9 N·m (P = .05), as higher moments were correlated with ligament thickening (correlation coefficient, 0.45) (P = .02). Conclusion This study establishes the association between medial elbow distraction captured by the internal adduction moment during pitching and UCL adaptations visible during MRI evaluation. PMID:21335342

  4. Performance of multiparametric magnetic resonance imaging in the evaluation and management of clinically low-risk prostate cancer

    PubMed Central

    Dianat, Seyed Saeid; Carter, H. Ballentine; Macura, Katarzyna J.

    2014-01-01

    Objective The purpose of this article is to review the multiparametric magnetic resonance imaging (mMRI) of the prostate and MR-guided prostate biopsy, and their role in the evaluation and management of men with low-risk prostate cancer. Methods We performed a literature review based on the MEDLINE database search for publications on the role of mMRI (a) in detection and localization of prostate cancer, prediction of tumor aggressiveness and progression and (b) in guiding targeted prostate biopsy. Results The mMRI, particularly diffusion-weighted imaging with T2-weighted imaging, is a useful tool for tumor localization in low-risk prostate cancer as it can detect lesions that are more likely missed on extended biopsy schemes and can identify clinically significant disease requiring definitive treatment. The MR-guided biopsy of the most suspicious lesions enables more accurate and safer approach to guide enrollment into the active surveillance program. However, the MR-guided biopsy is complex. The fusion of MRI data with transrectal ultrasound for the purpose of biopsy provides a more feasible technique with documented accurate sampling. Conclusion Although the mMRI is not routinely used for risk stratification and prognostic assessment in prostate cancer, it can provide valuable information to guide management of men with low-risk disease. Incorporation of mMRI into the workup and monitoring of patients with low-risk prostate cancer can help discriminate clinically significant disease from indolent disease. Targeted biopsy of MR-suspicious lesions enables accurate sampling of potentially aggressive tumors that may affect outcomes. PMID:23787297

  5. Comparison of magnetic resonance imaging (MRI) and contrast-enhanced ultrasound (CEUS) in the evaluation of unclear solid renal lesions.

    PubMed

    Rübenthaler, J; Paprottka, K; Marcon, J; Hameister, E; Hoffmann, K; Joiko, N; Reiser, M; Clevert, D A

    2016-01-01

    To compare the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) and magnetic resonance imaging (MRI) in the evaluation of unclear renal lesions to the histopathological outcome. A total of 36 patients with a single unclear solid renal lesion with initial imaging studies between 2005 and 2015 were included. CEUS and MRI were used for determining malignancy or benignancy and initial findings were correlated with the histopathological outcome. Out of the 36 renal masses a total of 28 lesions were malignant (77.8%) and 8 were found to be benign (22.2%). Diagnostic accuracy was testes by using the histopathological diagnosis as the gold standard. CEUS showed a sensitivity of 96.4%, a specificity of 100.0%, a positive predictive value (PPV) of 100.0% and a negative predictive value (NPV) of 88,9%. MRI showed a sensitivity of 96.4%, a specificity of 75.0%, a PPV of 93.1% and a NPV of 85.7%. Out of the 28 malignant lesions a total of 18 clear cell renal carcinomas, 6 papillary renal cell carcinomas and 4 other malignant lesions, e.g. metastases, were diagnosed. Out of the 8 benign lesions a total 3 angiomyolipomas, 2 oncocytomas, 1 benign renal cyst and 2 other benign lesions, e.g. renal adenomas were diagnosed. Using CEUS, 1 lesion was falsely identified as benign. Using MRI, 2 lesions were falsely identified as benign and 1 lesion was falsely identified as malignant. CEUS is an useful method which can be additionally used to clinically differentiate between malignant and benign renal lesions. CEUS shows a comparable sensitivity, specificity, PPV and NPV to MRI. In daily clinical routine, patients with contraindications for other imaging modalities can particularly benefit using this method.

  6. Cavity- and waveguide-resonators in electron paramagnetic resonance, nuclear magnetic resonance, and magnetic resonance imaging.

    PubMed

    Webb, Andrew

    2014-11-01

    Cavity resonators are widely used in electron paramagnetic resonance, very high field magnetic resonance microimaging and also in high field human imaging. The basic principles and designs of different forms of cavity resonators including rectangular, cylindrical, re-entrant, cavity magnetrons, toroidal cavities and dielectric resonators are reviewed. Applications in EPR and MRI are summarized, and finally the topic of traveling wave MRI using the magnet bore as a waveguide is discussed.

  7. Experimental evaluation of electrical conductivity imaging of anisotropic brain tissues using a combination of diffusion tensor imaging and magnetic resonance electrical impedance tomography

    NASA Astrophysics Data System (ADS)

    Sajib, Saurav Z. K.; Jeong, Woo Chul; Kyung, Eun Jung; Kim, Hyun Bum; Oh, Tong In; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2016-06-01

    Anisotropy of biological tissues is a low-frequency phenomenon that is associated with the function and structure of cell membranes. Imaging of anisotropic conductivity has potential for the analysis of interactions between electromagnetic fields and biological systems, such as the prediction of current pathways in electrical stimulation therapy. To improve application to the clinical environment, precise approaches are required to understand the exact responses inside the human body subjected to the stimulated currents. In this study, we experimentally evaluate the anisotropic conductivity tensor distribution of canine brain tissues, using a recently developed diffusion tensor-magnetic resonance electrical impedance tomography method. At low frequency, electrical conductivity of the biological tissues can be expressed as a product of the mobility and concentration of ions in the extracellular space. From diffusion tensor images of the brain, we can obtain directional information on diffusive movements of water molecules, which correspond to the mobility of ions. The position dependent scale factor, which provides information on ion concentration, was successfully calculated from the magnetic flux density, to obtain the equivalent conductivity tensor. By combining the information from both techniques, we can finally reconstruct the anisotropic conductivity tensor images of brain tissues. The reconstructed conductivity images better demonstrate the enhanced signal intensity in strongly anisotropic brain regions, compared with those resulting from previous methods using a global scale factor.

  8. Experimental evaluation of electrical conductivity imaging of anisotropic brain tissues using a combination of diffusion tensor imaging and magnetic resonance electrical impedance tomography

    SciTech Connect

    Sajib, Saurav Z. K.; Jeong, Woo Chul; Oh, Tong In; Kim, Hyung Joong E-mail: ejwoo@khu.ac.kr; Woo, Eung Je E-mail: ejwoo@khu.ac.kr; Kyung, Eun Jung; Kim, Hyun Bum; Kwon, Oh In

    2016-06-15

    Anisotropy of biological tissues is a low-frequency phenomenon that is associated with the function and structure of cell membranes. Imaging of anisotropic conductivity has potential for the analysis of interactions between electromagnetic fields and biological systems, such as the prediction of current pathways in electrical stimulation therapy. To improve application to the clinical environment, precise approaches are required to understand the exact responses inside the human body subjected to the stimulated currents. In this study, we experimentally evaluate the anisotropic conductivity tensor distribution of canine brain tissues, using a recently developed diffusion tensor-magnetic resonance electrical impedance tomography method. At low frequency, electrical conductivity of the biological tissues can be expressed as a product of the mobility and concentration of ions in the extracellular space. From diffusion tensor images of the brain, we can obtain directional information on diffusive movements of water molecules, which correspond to the mobility of ions. The position dependent scale factor, which provides information on ion concentration, was successfully calculated from the magnetic flux density, to obtain the equivalent conductivity tensor. By combining the information from both techniques, we can finally reconstruct the anisotropic conductivity tensor images of brain tissues. The reconstructed conductivity images better demonstrate the enhanced signal intensity in strongly anisotropic brain regions, compared with those resulting from previous methods using a global scale factor.

  9. Evaluation of magnetic resonance imaging abnormalities in juvenile onset neuropsychiatric systemic lupus erythematosus.

    PubMed

    Al-Obaidi, M; Saunders, D; Brown, S; Ramsden, L; Martin, N; Moraitis, E; Pilkington, C A; Brogan, P A; Eleftheriou, D

    2016-10-01

    The aim of this study was to describe the abnormalities identified with conventional MRI in children with neuropsychiatric systemic lupus erythematosus (NPSLE). This was single-centre (Great Ormond Street Hospital, London) retrospective case series of patients with juvenile NPSLE seen in 2003-2013. Brain MR images of the first episode of active NPSLE were reviewed. All patients fulfilled the 1999 ACR case definitions for NPSLE syndromes. Presenting neuropsychiatric manifestations, immunological findings and treatment are reported. Results are expressed as median and ranges or percentages. Fisher's exact test was used to identify clinical predictors of abnormal MRI. A total of 27 patients (22 females), median age 11 years (4-15), were identified. Presenting clinical symptoms included the following: headaches (85.1 %), mood disorder/depression (62.9 %), seizures (22.2 %), acute psychosis (18.5 %), cognitive dysfunction (14.8 %), movement disorder (14.8 %), acute confusional state (14.8 %), aseptic meningitis (7.4 %), demyelinating syndrome (3.7 %), myelopathy (3.7 %), dysautonomia (3.7 %) and cranial neuropathy (3.7 %). The principal MR findings were as follows: (1) absence of MRI abnormalities despite signs and symptoms of active NPSLE (59 %); (2) basilar artery territory infarction (3 %); (3) focal white matter hyperintensities on T2-weighted imaging (33 %); (4) cortical grey matter lesions (3 %); and (5) brain atrophy (18.5 %). The presence of an anxiety disorder strongly associated with abnormal MRI findings (p = 0.008). In over half the children with NPSLE, no conventional MRI abnormalities were observed; white matter hyperintensities were the most commonly described abnormalities. Improved MR techniques coupled with other alternative diagnostic imaging modalities may improve the detection rate of brain involvement in juvenile NPSLE.

  10. Evaluation of Variable Density and Data-Driven K-Space Undersampling for Compressed Sensing Magnetic Resonance Imaging.

    PubMed

    Zijlstra, Frank; Viergever, Max A; Seevinck, Peter R

    2016-06-01

    The aim of this study was to investigate the influence of variable density and data-driven k-space undersampling patterns on reconstruction quality for compressed sensing (CS) magnetic resonance imaging to provide recommendations on how to avoid suboptimal CS reconstructions. First, we investigated the influence of randomness and sampling density on the reconstruction quality when using random variable density and variable density Poisson disk undersampling. Compressed sensing reconstructions on 1 knee and 2 brain data sets were compared with fully sampled data sets and reconstruction errors were measured. Sampling coherence was evaluated on the undersampling patterns to investigate whether there was a relation between this coherence measure and reconstruction error.Second, we investigated whether data-driven undersampling methods could improve reconstruction quality when 1 or more fully sampled scans are available as a training set. We implemented 3 different data-driven undersampling methods: (1) Monte Carlo optimization of variable density and variable density Poisson disk undersampling, (2) calculating sampling probabilities directly from the k-space power spectra of the training data, and (3) iterative design of undersampling patterns based on CS reconstruction errors in k-space.Two cross-validation experiments were set up using retrospective undersampling to evaluate the 3 data-driven methods and the influence of the size of the training set. Furthermore, in an experiment that included prospective under sampling, we show the practical applicability of 2 of the data-driven methods. Compressed sensing reconstruction quality was measured with both the normalized root-mean-square error metric and the mean structural similarity index measure. Different optimal variable sampling densities were found for each of the data sets, showing that the optimal sampling density is data dependent. Choosing a sampling density other than the optimal density decreased

  11. Pediatric Body Magnetic Resonance Imaging.

    PubMed

    Kandasamy, Devasenathipathy; Goyal, Ankur; Sharma, Raju; Gupta, Arun Kumar

    2016-09-01

    Magnetic resonance imaging (MRI) is a radiation-free imaging modality with excellent contrast resolution and multiplanar capabilities. Since ionizing radiation is an important concern in the pediatric population, MRI serves as a useful alternative to computed tomography (CT) and also provides additional clues to diagnosis, not discernible on other investigations. Magnetic resonance cholangiopancreatography (MRCP), urography, angiography, enterography, dynamic multiphasic imaging and diffusion-weighted imaging provide wealth of information. The main limitations include, long scan time, need for sedation/anesthesia, cost and lack of widespread availability. With the emergence of newer sequences and variety of contrast agents, MRI has become a robust modality and may serve as a one-stop shop for both anatomical and functional information.

  12. Enhanced Long-Term Brain Magnetic Resonance Imaging Evaluation of Children with Sickle Cell Disease after Hematopoietic Cell Transplantation.

    PubMed

    Green, Nancy S; Bhatia, Monica; Griffith, Erica Y; Qureshi, Mahvish; Briamonte, Courtney; Savone, Mirko; Sands, Stephen; Lee, Margaret T; Lignelli, Angela; Brickman, Adam M

    2017-04-01

    Progressive neurovasculopathy in children with sickle cell disease (SCD) results in decreased cognitive function and quality of life (QoL). Hematopoietic cell transplantation (HCT) is believed to halt progression of neurovasculopathy. Quantitative analysis of T2-weighted fluid attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) for white matter hyperintensity (WMH) burden provides a meaningful estimate of small vessel cerebrovascular disease. We asked if quantitative analysis of WMH could complement standardized clinical assessment of MRI/magnetic resonance angiography (MRA) for assessing SCD central nervous system vasculopathy before and after HCT. Retrospective longitudinal clinical examination of scheduled annual MRI/MRA and quantitative analysis of WMH were performed before and 1 to 7 years after HCT at scheduled annual intervals, along with QoL measurements, in children who had engrafted after HCT. Of 18 patients alive and persistently engrafted (median age, 9.1 years), pretransplantation MRI demonstrated that 9 and 5 had sickle-related stroke and/or small infarcts, respectively. Patients were divided into WMH severity tertiles based on pretransplantation WMH volumes. MRI and WMH were assessed 1 to 7 years after HCT. MRI/MRA and WMH volume were stable or slightly better in 17 of 18 patients. By parent- and self-report, post-HCT QoL improved for children in the lowest WMH tertile significantly more than in the other groups. Based on this single-institution retrospective sample, we report that WMH appears to quantitatively support MRI-based findings that HCT stabilizes long-term small and large vessel cerebrovascular changes and is associated with the degree of improved QoL. While confirmation in larger prospective studies and evaluation by neurocognitive testing are needed, these findings suggest that WMH is a useful biomarker of neurovasculopathy after transplantation for SCD.

  13. Coronary magnetic resonance imaging.

    PubMed

    Manning, Warren J; Nezafat, Reza; Appelbaum, Evan; Danias, Peter G; Hauser, Thomas H; Yeon, Susan B

    2007-02-01

    This article highlights the technical challenges and general imaging strategies for coronary MRI. This is followed by a review of the clinical results for the assessment of anomalous CAD, coronary artery aneurysms, native vessel integrity, and coronary artery bypass graft disease using the more commonly applied MRI methods. It concludes with a brief discussion of the advantages/disadvantages and clinical results comparing coronary MRI with multidetector CT (MDCT) coronary angiography.

  14. MAGNETIC RESONANCE IMAGING OF THE HIP FOR THE EVALUATION OF FEMOROACETABULAR IMPINGEMENT; PAST, PRESENT, AND FUTURE

    PubMed Central

    Riley, Geoffrey M.; McWalter, Emily J.; Stevens, Kathryn J.; Safran, Marc R.; Lattanzi, Riccardo; Gold, Garry E.

    2014-01-01

    The concept of femoroacetabular impingement (FAI) has, in a relatively short time, come to the forefront of orthopedic imaging. In just a few short years MRI findings that were in the past ascribed to degenerative change, normal variation, or other pathologies must now be described and included in radiology reports, as they have been shown, or are suspected to be related to, FAI. Crucial questions have come up in this time, including: what is the relationship of bony morphology to subsequent cartilage and labral damage, and most importantly, how is this morphology related to the development of osteoarthritis? In this review we attempt to place a historical perspective on the controversy, provide guidelines for interpretation of MRI examinations of patients with suspected FAI, and offer a glimpse into the future of MRI of this complex condition. PMID:25155435

  15. Low field magnetic resonance imaging

    DOEpatents

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  16. Stereological evaluation of the volume and volume fraction of newborns' brain compartment and brain in magnetic resonance images.

    PubMed

    Nisari, Mehtap; Ertekin, Tolga; Ozçelik, Ozlem; Cınar, Serife; Doğanay, Selim; Acer, Niyazi

    2012-11-01

    Brain development in early life is thought to be critical period in neurodevelopmental disorder. Knowledge relating to this period is currently quite limited. This study aimed to evaluate the volume relation of total brain (TB), cerebrum, cerebellum and bulbus+pons by the use of Archimedes' principle and stereological (point-counting) method and after that to compare these approaches with each other in newborns. This study was carried out on five newborn cadavers mean weighing 2.220 ± 1.056 g with no signs of neuropathology. The mean (±SD) age of the subjects was 39.7 (±1.5) weeks. The volume and volume fraction of the total brain, cerebrum, cerebellum and bulbus+pons were determined on magnetic resonance (MR) images using the point-counting approach of stereological methods and by the use of fluid displacement technique. The mean (±SD) TB, cerebrum, cerebellum and bulbus+pons volumes by fluid displacement were 271.48 ± 78.3, 256.6 ± 71.8, 12.16 ± 6.1 and 2.72 ± 1.6 cm3, respectively. By the Cavalieri principle (point-counting) using sagittal MRIs, they were 262.01 ± 74.9, 248.11 ± 68.03, 11.68 ± 6.1 and 2.21 ± 1.13 cm3, respectively. The mean (± SD) volumes by point-counting technique using axial MR images were 288.06 ± 88.5, 275.2 ± 83.1, 19.75 ± 5.3 and 2.11 ± 0.7 cm3, respectively. There were no differences between the fluid displacement and point-counting (using axial and sagittal images) for all structures (p > 0.05). This study presents the basic data for studies relative to newborn's brain volume fractions according to two methods. Stereological (point-counting) estimation may be accepted a beneficial and new tool for neurological evaluation in vivo research of the brain. Based on these techniques we introduce here, the clinician may evaluate the growth of the brain in a more efficient and precise manner.

  17. Magnetic Resonance Imaging of Spinal Emergencies.

    PubMed

    Kawakyu-O'Connor, Daniel; Bordia, Ritu; Nicola, Refky

    2016-05-01

    Magnetic resonance (MR) imaging of the spine is increasingly being used in the evaluation of spinal emergencies because it is highly sensitive and specific in the diagnosis of acute conditions of the spine. The prompt and accurate recognition allows for appropriate medical and surgical intervention. This article reviews the MR imaging features of common emergent conditions, such as spinal trauma, acute disc herniation, infection, and tumors. In addition, we describe common MR imaging sequences, discuss challenges encountered in emergency imaging of the spine, and illustrate multiple mimics of acute conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Evaluation of magnetic resonance imaging issues for implantable microfabricated magnetic actuators.

    PubMed

    Lee, Hyowon; Xu, Qing; Shellock, Frank G; Bergsneider, Marvin; Judy, Jack W

    2014-02-01

    The mechanical robustness of microfabricated torsional magnetic actuators in withstanding the strong static fields (7 T) and time-varying field gradients (17 T/m) produced by an MR system was studied in this investigation. The static and dynamic mechanical characteristics of 30 devices were quantitatively measured before and after exposure to both strong uniform and non-uniform magnetic fields. The results showed no statistically significant change in both the static and dynamic mechanical performance, which mitigate concerns about the mechanical stability of these devices in association with MR systems under the conditions used for this assessment. The MR-induced heating was also measured in a 3-T/128-MHz MR system. The results showed a minimal increase (1.6 °C) in temperature due to the presence of the magnetic microactuator array. Finally, the size of the MR-image artifacts created by the magnetic microdevices were quantified. The signal loss caused by the devices was approximately four times greater than the size of the device.

  19. Evaluation of efficacy of transcatheter arterial chemoembolization for hepatocellular carcinoma using magnetic resonance diffusion-weighted imaging

    PubMed Central

    Wu, Xiao-Ming; Wang, Jun-Feng; Ji, Jian-Song; Chen, Ming-Gao; Song, Jian-Gang

    2017-01-01

    Although the efficacy of transcatheter arterial chemoembolization (TACE) has been recommended as first-line therapy for nonsurgical patients with hepatocellular carcinoma (HCC), it is difficult to accurately predict the efficacy of TACE. Therefore, this study evaluated the efficacy of TACE for HCC using magnetic resonance (MR) diffusion-weighted imaging (DWI). A total of 84 HCC patients who received initial TACE were selected and assigned to the stable group (n=39) and the progressive group (n=45). Before TACE treatment, a contrast-enhanced MR scan and DWI (b=300, 600, and 800 s/mm2) were performed on all patients. The modified response evaluation criteria in solid tumors were used for evaluation of tumor response. Receiver operating characteristic curve was employed to predict the value of apparent diffusion coefficient (ADC) for TACE efficacy. The ADC values of HCC patients in the progressive group were higher than those in the stable group at different b-values (b=300, 600, and 800 s/mm2) before TACE treatment. The area under the curve of ADC values with b-values of 300, 600, and 800 s/mm2 were 0.693, 0.724, and 0.746; the threshold values were 1.94×10−3 mm2/s, 1.28×10−3 mm2/s, and 1.20×10−3 mm2/s; the sensitivity values were 55.6%, 77.8%, and 73.3%; and the specificity values were 82.1%, 61.5%, and 71.8%, respectively. Our findings indicate that the ADC values of MR-DWI may accurately predict the efficacy of TACE in the treatment of HCC patients. PMID:28352195

  20. Noninvasive evaluation of global and regional left ventricular function using computed tomography and magnetic resonance imaging: a meta-analysis.

    PubMed

    Kaniewska, Malwina; Schuetz, Georg M; Willun, Steffen; Schlattmann, Peter; Dewey, Marc

    2017-04-01

    To compare the diagnostic accuracy of computed tomography (CT) in the assessment of global and regional left ventricular (LV) function with magnetic resonance imaging (MRI). MEDLINE, EMBASE and ISI Web of Science were systematically reviewed. Evaluation included: ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and left ventricular mass (LVM). Differences between modalities were analysed using limits of agreement (LoA). Publication bias was measured by Egger's regression test. Heterogeneity was evaluated using Cochran's Q test and Higgins I(2) statistic. In the presence of heterogeneity the DerSimonian-Laird method was used for estimation of heterogeneity variance. Fifty-three studies including 1,814 patients were identified. The mean difference between CT and MRI was -0.56 % (LoA, -11.6-10.5 %) for EF, 2.62 ml (-34.1-39.3 ml) for EDV and 1.61 ml (-22.4-25.7 ml) for ESV, 3.21 ml (-21.8-28.3 ml) for SV and 0.13 g (-28.2-28.4 g) for LVM. CT detected wall motion abnormalities on a per-segment basis with 90 % sensitivity and 97 % specificity. CT is accurate for assessing global LV function parameters but the limits of agreement versus MRI are moderately wide, while wall motion deficits are detected with high accuracy. • CT helps to assess patients with coronary artery disease (CAD). • MRI is the reference standard for evaluation of left ventricular function. • CT provides accurate assessment of global left ventricular function.

  1. Diffusion-Weighted Magnetic Resonance Imaging to Evaluate Major Salivary Gland Function Before and After Radiotherapy

    SciTech Connect

    Dirix, Piet Keyzer, Frederik de; Vandecaveye, Vincent; Stroobants, Sigrid; Hermans, Robert; Nuyts, Sandra

    2008-08-01

    Purpose: To evaluate diffusion-weighted (DW)-MRI as a noninvasive tool to investigate major salivary gland function before and after radiotherapy (RT) for head and neck cancer (HNC). Methods and Materials: DW-MRI was performed in 8 HNC patients before and after parotid-sparing RT (mean dose to the contralateral parotid gland <26 Gy). A DW sequence was performed once at rest and then repeated continuously during salivary stimulation. Apparent diffusion coefficient (ADC) maps for both parotid and submandibular glands were calculated. Findings were compared with salivary gland scintigraphy. Results: Before RT, the mean ADC value at rest was significantly lower in the parotid than in the submandibular glands. During the first 5 min of stimulation, the ADC value of the salivary glands showed a decrease, followed by a steady increase until a peak ADC, significantly higher than the baseline value, was reached after a median of 17 min. The baseline ADC value at rest was significantly higher after RT than before RT in the nonspared salivary glands but not in the spared parotid glands. In the contralateral parotid glands, the same response was seen as before RT. This pattern was completely lost in the nonspared glands. These results corresponded with remaining or loss of salivary function, respectively, as confirmed by salivary gland scintigraphy. Conclusions: Diffusion-weighted-MRI allows noninvasive evaluation of functional changes in the major salivary glands after RT and is a promising tool for investigating radiation-induced xerostomia.

  2. A comparison of endoscopic ultrasound, magnetic resonance imaging, and exam under anesthesia for evaluation of Crohn's perianal fistulas.

    PubMed

    Schwartz, D A; Wiersema, M J; Dudiak, K M; Fletcher, J G; Clain, J E; Tremaine, W J; Zinsmeister, A R; Norton, I D; Boardman, L A; Devine, R M; Wolff, B G; Young-Fadok, T M; Diehl, N N; Pemberton, J H; Sandborn, W J

    2001-11-01

    To determine accuracy of endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI) for evaluation of Crohn's disease perianal fistulas. Thirty-four patients with suspected Crohn's disease perianal fistulas were prospectively enrolled in a blinded study comparing EUS, MRI, and examination under anesthesia (EUA). Fistulas were classified according to Parks' criteria, and a consensus gold standard was determined for each patient. Acceptable accuracy was defined as agreement with the consensus gold standard for > or =85% of patients. Three patients did not undergo MRI; 1 did not undergo EUS or EUA; and consensus could not be reached for 1. Thirty-two patients had 39 fistulas (20 trans-sphincteric, 5 extra-sphincteric, 6 recto-vaginal, 8 others) and 13 abscesses. The accuracy of all 3 modalities was > or =85%: EUS 29 of 32 (91%, confidence interval [CI] 75%-98%), MRI 26 of 30 (87%, CI 69%-96%), and EUA 29 of 32 (91%, CI 75%-98%). Accuracy was 100% when any 2 tests were combined. EUS, MRI, and EUA are accurate tests for determining fistula anatomy in patients with perianal Crohn's disease. The optimal approach may be combining any 2 of the 3 methods.

  3. Shoulder motion during tennis serve: dynamic and radiological evaluation based on motion capture and magnetic resonance imaging.

    PubMed

    Charbonnier, Caecilia; Chagué, Sylvain; Kolo, Frank C; Lädermann, Alexandre

    2015-08-01

    Rotator cuff and labral lesions in tennis players could be related to posterosuperior internal impingement or subacromial impingement during tennis serve. However, it is unknown which of these impingements are responsible for the lesions found in the tennis player's shoulder. Moreover, there is a lack of validated noninvasive methods and dynamic studies to ascertain impingement during motion. Ten intermediate or ex-professional tennis players were motion captured with an optical tracking system while performing tennis serves. The resulting computed motions were applied to patient-specific shoulder joints' 3D models based on magnetic resonance imaging (MRI) data. During motion simulation, impingements were detected and located using computer-assisted techniques. An MRI examination was also performed to evaluate the prevalence of shoulder lesions and to determine their relevance with the simulation findings. Simulation showed that internal impingement was frequently observed compared to subacromial impingement when serving. The computed zones of internal impingement were mainly located in the posterosuperior or superior region of the glenoid. These findings were relevant with respect to radiologically diagnosed damaged zones in the rotator cuff and glenoid labrum. Tennis players presented frequent radiographic signs of structural lesions that seem to be mainly related to posterosuperior internal impingement due to repetitive abnormal motion contacts. The present study indicates that the practice of tennis serve could lead with time to cartilage/tendon hyper compression, which could be damageable for the glenohumeral joint.

  4. Diagnostic value of gadobenate dimeglumine-enhanced hepatocyte-phase magnetic resonance imaging in evaluating hepatic fibrosis and hepatitis

    PubMed Central

    Li, Xiu-Mei; Chen, Zhu; Xiao, En-Hua; Shang, Quan-Liang; Ma, Cong

    2017-01-01

    AIM To evaluate the diagnostic value of gadobenate dimeglumine (Gd-BOPTA)-enhanced hepatocyte-phase magnetic resonance imaging (MRI) in evaluating hepatic fibrosis and hepatitis. METHODS Hepatocyte-phase images of Gd-BOPTA-enhanced MRI were retrospectively evaluated in 76 patients with chronic liver disease. These patients were classified into five groups according to either the histopathological fibrosis stage (S0-S4) or the histopathological hepatitis grade (G0-G4). The relative enhancement ratio (RE) of the liver parenchyma in the T1-vibe sequence was calculated by measuring the signal intensity before (SI pre) and 90 min after (SI post) intravenous injection of Gd-BOPTA using the following formula: RE = (SI post - SI pre)/SI pre. One-way analysis of variance was used to compare the difference between the relative RE in the hepatocyte phase (REh) and the stage of hepatic fibrosis and the grade of hepatitis. Pearson’s product-moment correlation analysis was used to evaluate the relationship between the REh and the levels of serologic liver functional parameters. RESULTS According to histopathological hepatic fibrosis stage, the 76 patients were classified into five groups: 16 in S0, 15 in S1, 21 in S2, 9 in S3, and 15 in S4 group. According to histopathological hepatitis grade, the 76 patients were also classified into five groups: 0 in G0, 44 in G1, 22 in G2, 8 in G3, and 2 in G3 group. With regard to the stage of hepatic fibrosis, REh showed significant differences between the S2 and S3 groups and between the S2 and S4 groups (P < 0.05), but no significant difference was observed between the other groups. With regard to the grade of hepatitis, REh showed significant differences between the G1 and G2 groups and between the G1 and G4 groups (P < 0.05), but no significant difference was observed between the other groups. Increased REh showed correlations with decreased serum levels of TB, ALT and AST (P < 0.05). CONCLUSION To some extent, measuring the REh using

  5. Evaluation of novel genetic algorithm generated schemes for positron emission tomography (PET)/magnetic resonance imaging (MRI) image fusion.

    PubMed

    Baum, K G; Schmidt, E; Rafferty, K; Krol, A; Helguera, María

    2011-12-01

    The use and benefits of a multimodality approach in the context of breast cancer imaging are discussed. Fusion techniques that allow multiple images to be viewed simultaneously are discussed. Many of these fusion techniques rely on the use of color tables. A genetic algorithm that generates color tables that have desired properties such as satisfying the order principle, the rows, and columns principle, have perceivable uniformity and have maximum contrast is introduced. The generated 2D color tables can be used for displaying fused datasets. The advantage the proposed method has over other techniques is the ability to consider a much larger set of possible color tables, ensuring that the best one is found. We asked radiologists to perform a set of tasks reading fused PET/MRI breast images obtained using eight different fusion techniques. This preliminary study clearly demonstrates the need and benefit of a joint display by estimating the inaccuracies incurred when using a side-by-side display. The study suggests that the color tables generated by the genetic algorithm are good choices for fusing MR and PET images. It is interesting to note that popular techniques such as the Fire/Gray and techniques based on the HSV color space, which are prevalent in the literature and clinical practice, appear to give poorer performance.

  6. Basic T1 Perfusion magnetic resonance imaging evaluation of the therapeutic effect of neoadjuvant chemotherapy in locally advanced cervical cancer.

    PubMed

    Fu, Chun; Feng, Xiaoyan; Bian, Dujun; Du, Wanping; Wang, Xiangquan; Zhao, Yan

    2013-09-01

    The objective of this study was to evaluate the dynamic changes of blood perfusion coinciding with tumor regression after neoadjuvant chemotherapy (NACT) in locally advanced cervical cancer (LACC). Thirty patients with LACC received conventional 3.0-T magnetic resonance imaging and perfusion-weighted imaging scans at 3 different times (before NACT, 2 weeks after the first NACT, and 2 weeks after the second NACT). Characteristics of time-intensity diagrams and patterns of blood perfusion maps according to the parameter of area under the curve (AUC) were observed. Eight perfusion parameters were compared among 3 time points at 2 different chemotherapy-sensitive groups by the software of Basic T1 Perfusion. The effective chemotherapy rate was 73.3% (22/30). The characteristic of time-intensity diagrams in cervical cancer was a rapid onset with plateau. There were 3 patterns of AUC perfusion maps. The common perfusion map was rich blood supply type in the effective chemotherapy group and peripheral blood supply type in the ineffective chemotherapy group. Four parameter values (relative enhancement, maximum enhancement, wash-in rate, and AUC) were significantly reduced 2 weeks after the second NACT than those before the therapy (P = 0.000; P = 0.009; P = 0.011; and P = 0.000) in the effective chemotherapy group, especially the value of relative enhancement 2 weeks after the first NACT, was obviously decreased compared to that before the therapy (P = 0.042). The value of time to peak 2 weeks after the second NACT was significantly longer than that before the therapy in the effective chemotherapy group (P = 0.001). There were no obvious changes of blood perfusion parameters among the 3 different times in the ineffective chemotherapy group. Tumor blood perfusion has obviously decreased after effective NACT in the treatment of LACC.

  7. Evaluation of aqueductal cerebrospinal fluid flow dynamics with phase-contrast cine magnetic resonance imaging in normal pediatric cases.

    PubMed

    Öztürk, Mehmet; Sığırcı, Ahmet; Ünlü, Serkan

    This study aimed to determine differences according to age groups and gender in the parameters of aqueductal cerebrospinal fluid (CSF) flow in childhood using phase-contrast cine magnetic resonance imaging (MRI) method. This prospective study included 47 boys and 36 girls for a total of 83 healthy children. The cases were divided into three groups depending on age as infants (1-12 months), children (12-120 months), and adolescents (120-204 months). To quantitatively evaluate CSF flow, images in the transverse plane were taken at the cerebral aqueduct level using the phase-contrast MR angiography technique in a 1.5-T MR unit. Peak and average velocity (cm/s), cranial direction, caudal direction and net volume (ml), and aqueduct area (mm(2)) were calculated. To assess differences between the groups, a one-way analysis of variance and least significant difference tests were used. A statistically significant difference was determined between children and adolescents in peak velocity and caudal direction volume (P=.012 and P=.039, respectively) and between infants and children in cranial direction volume (P=.036). Peak velocity, cranial direction, and net volume were higher in boys (P=.050, P=.016, and P=.029, respectively). There were no differences by age and gender in the aqueduct area. In conclusion, this study determined the normal values for the CSF flow parameters of velocity, volume, and aqueduct area using phase-contrast MRI in healthy children. Velocity and volume parameters varied according to age and sex and were not affected in the aqueductal area. Published by Elsevier Inc.

  8. Pre- and postoperative evaluation of partial anomalous pulmonary venous return: by 3-dimensional cardiovascular magnetic resonance imaging and cardiovascular computed tomography.

    PubMed

    Crestanello, Juan A; Daniels, Curt; Franco, Veronica; Raman, Subha V

    2010-01-01

    The pre- and postoperative evaluation of anomalous pulmonary venous return usually requires multiple invasive and noninvasive tests in order to obtain complete anatomic and functional data. Conversely, in a single setting, either cardiovascular magnetic resonance imaging or cardiovascular computed tomography can sufficiently reveal this information in adult patients. Herein, we present the cases of 2 patients with partial anomalous pulmonary venous return who underwent preoperative and postoperative evaluation by either method alone, and we discuss the benefits and limitations of each technique.

  9. Evaluation of ventricular geometry and performance in congenital heart disease utilizing magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Fogel, Mark A.

    1994-05-01

    We have recently embarked on a systematic evaluation of the regional and global mechanical processes of the systemic, morphologic right ventricle (RV) which is in either a single or dual chambered circulation as well as single left ventricles (LV). An MRI tagging technique which lays down 2 sets of parallel stripes perpendicular to each other on the myocardium as well as standard cine MRI were utilized. Finite strain analysis was applied to the grid lines to derive principle strains and the motion of the intersection points were tracked through systole to determine regional radial shortening and twist. Cine sequences were used to derive the various parameters of ventricular geometry and performance as well as visualizing flow profiles in the aorta. We noted a marked decrease in vol, EF, and CO in the Fontan group of patients when compared to other surgical subgroups. It is hypothesized that atrial stiffening by surgical placement of baffles may contribute to the observed changes in ventricular mechanics. Aortic flow profiles in the reconstructed aorta were noted to be heterogenous across the aortic diameter.

  10. Interventional Cardiovascular Magnetic Resonance Imaging

    PubMed Central

    Saikus, Christina E.; Lederman, Robert J.

    2010-01-01

    Cardiovascular magnetic resonance (CMR) combines excellent soft-tissue contrast, multiplanar views, and dynamic imaging of cardiac function without ionizing radiation exposure. Interventional cardiovascular magnetic resonance (iCMR) leverages these features to enhance conventional interventional procedures or to enable novel ones. Although still awaiting clinical deployment, this young field has tremendous potential. We survey promising clinical applications for iCMR. Next, we discuss the technologies that allow CMR-guided interventions and, finally, what still needs to be done to bring them to the clinic. PMID:19909937

  11. Development and evaluation of an algorithm for the computer-assisted segmentation of the human hypothalamus on 7-Tesla magnetic resonance images.

    PubMed

    Schindler, Stephanie; Schönknecht, Peter; Schmidt, Laura; Anwander, Alfred; Strauß, Maria; Trampel, Robert; Bazin, Pierre-Louis; Möller, Harald E; Hegerl, Ulrich; Turner, Robert; Geyer, Stefan

    2013-01-01

    Post mortem studies have shown volume changes of the hypothalamus in psychiatric patients. With 7T magnetic resonance imaging this effect can now be investigated in vivo in detail. To benefit from the sub-millimeter resolution requires an improved segmentation procedure. The traditional anatomical landmarks of the hypothalamus were refined using 7T T1-weighted magnetic resonance images. A detailed segmentation algorithm (unilateral hypothalamus) was developed for colour-coded, histogram-matched images, and evaluated in a sample of 10 subjects. Test-retest and inter-rater reliabilities were estimated in terms of intraclass-correlation coefficients (ICC) and Dice's coefficient (DC). The computer-assisted segmentation algorithm ensured test-retest reliabilities of ICC≥.97 (DC≥96.8) and inter-rater reliabilities of ICC≥.94 (DC = 95.2). There were no significant volume differences between the segmentation runs, raters, and hemispheres. The estimated volumes of the hypothalamus lie within the range of previous histological and neuroimaging results. We present a computer-assisted algorithm for the manual segmentation of the human hypothalamus using T1-weighted 7T magnetic resonance imaging. Providing very high test-retest and inter-rater reliabilities, it outperforms former procedures established at 1.5T and 3T magnetic resonance images and thus can serve as a gold standard for future automated procedures.

  12. Development and Evaluation of an Algorithm for the Computer-Assisted Segmentation of the Human Hypothalamus on 7-Tesla Magnetic Resonance Images

    PubMed Central

    Schmidt, Laura; Anwander, Alfred; Strauß, Maria; Trampel, Robert; Bazin, Pierre-Louis; Möller, Harald E.; Hegerl, Ulrich; Turner, Robert; Geyer, Stefan

    2013-01-01

    Post mortem studies have shown volume changes of the hypothalamus in psychiatric patients. With 7T magnetic resonance imaging this effect can now be investigated in vivo in detail. To benefit from the sub-millimeter resolution requires an improved segmentation procedure. The traditional anatomical landmarks of the hypothalamus were refined using 7T T1-weighted magnetic resonance images. A detailed segmentation algorithm (unilateral hypothalamus) was developed for colour-coded, histogram-matched images, and evaluated in a sample of 10 subjects. Test-retest and inter-rater reliabilities were estimated in terms of intraclass-correlation coefficients (ICC) and Dice's coefficient (DC). The computer-assisted segmentation algorithm ensured test-retest reliabilities of ICC≥.97 (DC≥96.8) and inter-rater reliabilities of ICC≥.94 (DC = 95.2). There were no significant volume differences between the segmentation runs, raters, and hemispheres. The estimated volumes of the hypothalamus lie within the range of previous histological and neuroimaging results. We present a computer-assisted algorithm for the manual segmentation of the human hypothalamus using T1-weighted 7T magnetic resonance imaging. Providing very high test-retest and inter-rater reliabilities, it outperforms former procedures established at 1.5T and 3T magnetic resonance images and thus can serve as a gold standard for future automated procedures. PMID:23935821

  13. [Magnetic resonance imaging and pathological evaluation of vacuum sealing drainage efficacy of early treated limb gunshot].

    PubMed

    Li, Ronggang; Liu, Xingyan; Chen, Keming; Ye, Jianjun; Gao, Mingxuan; Ge, Baofeng; Wang, Yong; Xiong, Faming; Liang, Jianping

    2010-03-01

    Gunshot wound spreads to the surrounding tissues and organs, it is difficult to debride and easy to infect. The conventional treatment is thorough, extensive debridement, fully open drainage, which often causes normal tissue damage and complications. To evaluate the effectiveness of vacuum sealing drainage (VSD) treating the penetrating wound in porcine extremity by MRI and pathological methods so as to provide theoretical basis for future clinical use. Eight healthy adult pigs, weighing (45 +/- 5) kg, were selected. Eight pairs of hind limb penetrating wounds (16 wounds) were made by using Chinese-made 95-type rifle at 25 meters distance, which were randomly divided into experimental group (left side, n=8) and the control group (right side, n=8). After debriding and disinfecting the penetrating wounds at 6 hours after injury, wounds were treated with VSD in experimental group. The ballistics exports of the wounds were covered with single-layer gauze and imports were directly sutured and covered with sterile gauze in control group. The trajectory and the general condition of the adjacent skin were observed. MRI and histological observation were taken at 5, 24, 48, and 72 hours after injury, bacterial counting analysis was done at 0, 12, 24, 48, and 72 hours after injury. The aperture of the trajectory exit and entry were (5.00 +/- 2.50) cm and (0.30 +/- 0.15) cm immediately after injury. The wound surface was clean, rosy without leakage and swelling after 72 hours in experimental group; wound and adjacent tissue were swelling obviously, pus, muscle necrosis and exfoliative tissue was observed, and deep defect cavity at the trajectory exit could be seen in control group. MRI showed that pairs of linear low signal in T1WI and T2WI was seen in trajectory of experimental group at 5 hours after injury, and signal in T1WI gradually increased at disrupted area and tissue deformation area at 24, 48, and 72 hours; in control group, low signal in T1WI was observed at 5 hours

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

    MedlinePlus

    ... to 2-Year-Old Magnetic Resonance Imaging (MRI): Brain KidsHealth > For Parents > Magnetic Resonance Imaging (MRI): Brain ... child may be given headphones to listen to music or earplugs to block the noise, and will ...

  15. Magnetic Resonance Imaging of Electrolysis.

    PubMed Central

    Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris

    2015-01-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research. PMID:25659942

  16. Magnetic Resonance Imaging of Electrolysis.

    NASA Astrophysics Data System (ADS)

    Meir, Arie; Hjouj, Mohammad; Rubinsky, Liel; Rubinsky, Boris

    2015-02-01

    This study explores the hypothesis that Magnetic Resonance Imaging (MRI) can image the process of electrolysis by detecting pH fronts. The study has relevance to real time control of cell ablation with electrolysis. To investigate the hypothesis we compare the following MR imaging sequences: T1 weighted, T2 weighted and Proton Density (PD), with optical images acquired using pH-sensitive dyes embedded in a physiological saline agar solution phantom treated with electrolysis and discrete measurements with a pH microprobe. We further demonstrate the biological relevance of our work using a bacterial E. Coli model, grown on the phantom. The results demonstrate the ability of MRI to image electrolysis produced pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E. Coli model grown on the phantom. The results are promising and invite further experimental research.

  17. Evaluation of the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer, according to the American College of Radiology criteria

    PubMed Central

    Boaventura, Camila Silva; Rodrigues, Daniel Padilha; Silva, Olimpio Antonio Cornehl; Beltrani, Fabrício Henrique; de Melo, Rayssa Araruna Bezerra; Bitencourt, Almir Galvão Vieira; Mendes, Gustavo Gomes; Chojniak, Rubens

    2017-01-01

    Objective To evaluate the indications for performing magnetic resonance imaging of the female pelvis at a referral center for cancer. Materials and Methods This was a retrospective, single-center study, conducted by reviewing medical records and imaging reports. We included 1060 female patients who underwent magnetic resonance imaging of the pelvis at a cancer center between January 2013 and June 2014. The indications for performing the examination were classified according to the American College of Radiology (ACR) criteria. Results The mean age of the patients was 52.6 ± 14.8 years, and 49.8% were perimenopausal or postmenopausal. The majority (63.9%) had a history of cancer, which was gynecologic in 29.5% and nongynecologic in 34.4%. Of the patients evaluated, 44.0% had clinical complaints, the most common being pelvic pain (in 11.5%) and bleeding (in 9.8%), and 34.7% of patients had previously had abnormal findings on ultrasound. Most (76.7%) of the patients met the criteria for undergoing magnetic resonance imaging, according to the ACR guidelines. The main indications were evaluation of tumor recurrence after surgical resection (in 25.9%); detection and staging of gynecologic neoplasms (in 23.3%); and evaluation of pelvic pain or of a mass (in 17.1%). Conclusion In the majority of the cases evaluated, magnetic resonance imaging was clearly indicated according to the ACR criteria. The main indication was local recurrence after surgical treatment of pelvic malignancies, which is consistent with the routine protocols at cancer centers. PMID:28298725

  18. Comparative performance evaluation of automated segmentation methods of hippocampus from magnetic resonance images of temporal lobe epilepsy patients

    PubMed Central

    Hosseini, Mohammad-Parsa; Nazem-Zadeh, Mohammad-Reza; Pompili, Dario; Jafari-Khouzani, Kourosh; Elisevich, Kost; Soltanian-Zadeh, Hamid

    2016-01-01

    Purpose: Segmentation of the hippocampus from magnetic resonance (MR) images is a key task in the evaluation of mesial temporal lobe epilepsy (mTLE) patients. Several automated algorithms have been proposed although manual segmentation remains the benchmark. Choosing a reliable algorithm is problematic since structural definition pertaining to multiple edges, missing and fuzzy boundaries, and shape changes varies among mTLE subjects. Lack of statistical references and guidance for quantifying the reliability and reproducibility of automated techniques has further detracted from automated approaches. The purpose of this study was to develop a systematic and statistical approach using a large dataset for the evaluation of automated methods and establish a method that would achieve results better approximating those attained by manual tracing in the epileptogenic hippocampus. Methods: A template database of 195 (81 males, 114 females; age range 32–67 yr, mean 49.16 yr) MR images of mTLE patients was used in this study. Hippocampal segmentation was accomplished manually and by two well-known tools (FreeSurfer and hammer) and two previously published methods developed at their institution [Automatic brain structure segmentation (ABSS) and LocalInfo]. To establish which method was better performing for mTLE cases, several voxel-based, distance-based, and volume-based performance metrics were considered. Statistical validations of the results using automated techniques were compared with the results of benchmark manual segmentation. Extracted metrics were analyzed to find the method that provided a more similar result relative to the benchmark. Results: Among the four automated methods, ABSS generated the most accurate results. For this method, the Dice coefficient was 5.13%, 14.10%, and 16.67% higher, Hausdorff was 22.65%, 86.73%, and 69.58% lower, precision was 4.94%, −4.94%, and 12.35% higher, and the root mean square (RMS) was 19.05%, 61.90%, and 65.08% lower than

  19. Evaluation of diagnostic utility of multidetector computed tomography and magnetic resonance imaging in blunt pancreatic trauma: a prospective study.

    PubMed

    Panda, Ananya; Kumar, Atin; Gamanagatti, Shivanand; Bhalla, Ashu Seith; Sharma, Raju; Kumar, Subodh; Mishra, Biplab

    2015-04-01

    Blunt pancreatic trauma is an uncommon injury with high morbidity and mortality. Retrospective analyses of computed tomography (CT) performance report CT to have variable sensitivity in diagnosing pancreatic injury. Both a prospective analysis of multidetector CT (MDCT) performance and diagnostic utility of magnetic resonance imaging (MRI) in acute blunt pancreatic injury remain unexplored. To prospectively evaluate the utility of MDCT with MRI correlation in patients with blunt pancreatic trauma using intraoperative findings as the gold standard for analysis. The contrast-enhanced CT (CECT) scans of patients admitted with blunt abdominal trauma were prospectively evaluated for CT signs of pancreatic injury. Patients detected to have pancreatic injury on CT were assigned a CT grade of injury according to American Association for Surgery of Trauma classification. MRI was performed in patients not undergoing immediate laparotomy and MRI grade independent of CT grade was assigned. Surgical grade was taken as gold standard and accuracy of CT and MRI for grading pancreatic injury and pancreatic ductal injury (PDI) was calculated. A quantitative and qualitative comparison of MRI was also done with CT to determine the performance of MRI in acute pancreatic injury. Thirty out of 1198 patients with blunt trauma abdomen were detected to have pancreatic injury on CT, which was surgically confirmed in 24 patients. Seventeen underwent MRI and surgical correlation was available in 14 patients. CT and MRI correctly identified the grade of pancreatic injury in 91.7% (22/24) and 92.86% (13/14) patients, respectively. Both CT and MRI correctly identified PDI in 18/19 and 11/12 patients, respectively, with good inter-modality agreement of 88.9% (kappa value of 0.78). MRI also qualitatively added to the information provided by CT and increased diagnostic confidence in 58.8% of patients. MDCT performs well in grading pancreatic injury and evaluating pancreatic ductal injury. MRI is

  20. Synthesis and Evaluation of GdIII-Based Magnetic Resonance Contrast Agents for Molecular Imaging of Prostate-Specific Membrane Antigen**

    PubMed Central

    Ngen, Ethel J.; Rotz, Matthew W.; Kakkad, Samata; Lisok, Ala; Pracitto, Richard; Pullambhatla, Mrudula; Chen, Zhengping; Shah, Tariq; Artemov, Dmitri; Meade, Thomas J.; Bhujwalla, Zaver M.; Pomper, Martin G.

    2016-01-01

    Magnetic resonance (MR) imaging is advantageous because it concurrently provides anatomic, functional, and molecular information. MR molecular imaging can combine the high spatial resolution of this established clinical modality with molecular profiling in vivo. However, as a result of the intrinsically low sensitivity of MR imaging, high local concentrations of biological targets are required to generate discernable MR contrast. We hypothesize that the prostate-specific membrane antigen (PSMA), an attractive target for imaging and therapy of prostate cancer, could serve as a suitable biomarker for MR-based molecular imaging. We have synthesized three new high-affinity, low-molecular-weight GdIII-based PSMA-targeted contrast agents containing one to three GdIII chelates per molecule. We evaluated the relaxometric properties of these agents in solution, in prostate cancer cells, and in an in vivo experimental model to demonstrate the feasibility of PSMA-based MR molecular imaging. PMID:26212031

  1. Basics of magnetic resonance imaging

    SciTech Connect

    Oldendorf, W.; Oldendorf, W. Jr.

    1988-01-01

    Beginning with the behavior of a compass needle in a magnetic field, this text uses analogies from everyday experience to explain the phenomenon of nuclear magnetic resonance and how it is used for imaging. Using a minimum of scientific abbreviations and symbols, the basics of tissue visualization and characterization are presented. A description of the various types of magnets and scanners is followed by the practical advantages and limitations of MRI relative to x-ray CT scanning.

  2. Fast fetal magnetic resonance imaging.

    PubMed

    Sandrasegaran, Kumaresan; Lall, Chandana; Aisen, Alex A; Rajesh, Arumugam; Cohen, Mervyn D

    2005-01-01

    Fetal magnetic resonance imaging (MRI) can be used as a problem-solving tool when ultrasonic findings are equivocal. The role of fetal MRI has increased as obstetricians become aware of its potential and in utero therapy for anomalies becomes increasingly sophisticated. In this pictorial essay, we present a wide range of anomalies diagnosed or confirmed using MRI and discuss findings that help in the differential diagnosis.

  3. Magnetic resonance imaging of the elbow.

    PubMed

    Stevens, Kathryn J

    2010-05-01

    Elbow pain is frequently encountered in clinical practice and can result in significant morbidity, particularly in athletes. Magnetic resonance imaging (MRI) is an excellent diagnostic imaging tool for the evaluation of soft tissue and osteochondral pathology around the elbow. Recent advances in magnetic field strength and coil design have lead to improved spatial resolution and superior soft tissue contrast, making it ideal for visualization of complex joint anatomy. This article describes the normal imaging appearances of anatomy around the elbow and reviews commonly occurring ligamentous, myotendinous, neural, and bursal pathology around the elbow.

  4. Nerves on magnetic resonance imaging.

    PubMed Central

    Collins, J. D.; Shaver, M. L.; Batra, P.; Brown, K.

    1989-01-01

    Nerves are often visualized on magnetic resonance imaging (MRI) studies of the soft tissues on the chest and shoulder girdle. To learn the reasons for the contrast between the nerves and adjacent tissues, the authors obtained a fresh specimen containing part of the brachial plexus nerves from the left axilla and compared MRI with x-ray projections and photomicrographs of histologic sections. The results suggest that the high signals from the nerves stand out in contrast to the low signals from their rich vascular supply. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6A Figure 6B Figure 7 PMID:2733051

  5. Evaluation of the reproducibility of a protocol for the pharmacokinetic study of breast tumors by dynamic magnetic resonance imaging.

    PubMed

    Etxano, J; García-Lallana Valbuena, A; Antón Ibáñez, I; Elizalde, A; Pina, L; García-Foncillas, J; Boni, V

    2015-01-01

    To evaluate the reproducibility of a protocol for dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the pharmacokinetic study of breast tumors. We carried out this prospective study from October 2009 through December 2009. We studied 12 patients with stage ii-iii invasive breast cancer without prior treatment. Our center's research ethics committee approved the study. The 12 patients underwent on two consecutive days DCE-MRI with a high temporal resolution protocol (21 acquisitions/minute). The data obtained in an ROI traced around the largest diameter of the tumor (ROI 1) and in another ROI traced around the area of the lesion's highest K(trans) intensity (ROI 2) were analyzed separately. We used parametric and nonparametric statistical tests to study the reproducibility and concordance of the principal pharmacokinetic variables (K(trans), Kep, Ve and AUC90). The correlations were very high (r>.80; P<.01) for all the variables for ROI 1 and high (r=.70-.80; P<.01) for all the variables for ROI 2, with the exception of Ve both in ROI 1 (r=.44; P=.07) and in ROI 2 (r=.13; P=.235). There were no statistically significant differences between the two studies in the values obtained for K(trans), Kep and AUC90 (P>.05 for each), but there was a statistically significant difference between the two studies in the values obtained for Ve in ROI 2 (P=.008). The high temporal resolution protocol for DCE-MRI used at out center is very reproducible for the principal pharmacokinetic constants of breast. Copyright © 2012 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  6. Use of a radio frequency shield during 1.5 and 3.0 Tesla magnetic resonance imaging: experimental evaluation

    PubMed Central

    Favazza, Christopher P; King, Deirdre M; Edmonson, Heidi A; Felmlee, Joel P; Rossman, Phillip J; Hangiandreou, Nicholas J; Watson, Robert E; Gorny, Krzysztof R

    2014-01-01

    Radiofrequency (RF) shields have been recently developed for the purpose of shielding portions of the patient’s body during magnetic resonance imaging (MRI) examinations. We present an experimental evaluation of a commercially available RF shield in the MRI environment. All tests were performed on 1.5 T and 3.0 T clinical MRI scanners. The tests were repeated with and without the RF shield present in the bore, for comparison. Effects of the shield, placed within the scanner bore, on the RF fields generated by the scanner were measured directly using tuned pick-up coils. Attenuation, by as much as 35 dB, of RF field power was found inside the RF shield. These results were supported by temperature measurements of metallic leads placed inside the shield, in which no measurable RF heating was found. In addition, there was a small, simultaneous detectable increase (∼1 dB) of RF power just outside the edges of the shield. For these particular scanners, the autocalibrated RF power levels were reduced for scan locations prescribed just outside the edges of the shield, which corresponded with estimations based on the pick-up coil measurements. Additionally, no significant heating during MRI scanning was observed on the shield surface. The impact of the RF shield on the RF fields inside the magnet bore is likely to be dependent on the particular model of the RF shield or the MRI scanner. These results suggest that the RF shield could be a valuable tool for clinical MRI practices. PMID:25378957

  7. Multidimensionally encoded magnetic resonance imaging.

    PubMed

    Lin, Fa-Hsuan

    2013-07-01

    Magnetic resonance imaging (MRI) typically achieves spatial encoding by measuring the projection of a q-dimensional object over q-dimensional spatial bases created by linear spatial encoding magnetic fields (SEMs). Recently, imaging strategies using nonlinear SEMs have demonstrated potential advantages for reconstructing images with higher spatiotemporal resolution and reducing peripheral nerve stimulation. In practice, nonlinear SEMs and linear SEMs can be used jointly to further improve the image reconstruction performance. Here, we propose the multidimensionally encoded (MDE) MRI to map a q-dimensional object onto a p-dimensional encoding space where p > q. MDE MRI is a theoretical framework linking imaging strategies using linear and nonlinear SEMs. Using a system of eight surface SEM coils with an eight-channel radiofrequency coil array, we demonstrate the five-dimensional MDE MRI for a two-dimensional object as a further generalization of PatLoc imaging and O-space imaging. We also present a method of optimizing spatial bases in MDE MRI. Results show that MDE MRI with a higher dimensional encoding space can reconstruct images more efficiently and with a smaller reconstruction error when the k-space sampling distribution and the number of samples are controlled. Copyright © 2012 Wiley Periodicals, Inc.

  8. Magnetic Resonance Imaging Features of Solitary Hypothalamitis.

    PubMed

    Zhang, Hua; Wang, Jing; Wu, Yue; Tang, Ying; Tao, Ran; Ye, Hongying; Yao, Zhenwei

    The study aimed to characterize magnetic resonance imaging (MRI) findings of solitary hypothalamitis and evaluate their clinical value in diagnosis. Magnetic resonance imaging scans, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and contrast-enhanced T1-weighted sequences, of 8 biopsy-proven hypothalamitis lesions were retrospectively analyzed along with MRI features including size, shape, signal intensity, enhancement pattern, correlation with adjacent tissues, and changes in infundibular stalk and sella turcica. Of 8 patients, 5 were diagnosed with lymphoplasmacytic proliferative inflammation, 2 with Langerhans cell histocytosis, and 1 with Rosai-Dorfman disease. Solitary hypothalamitis predominantly demonstrated mild hypointensity/isointensity in T1WI and mild hyperintensity in T2-weighted imaging. In contrast-enhanced T1WI, all lesions showed heterogeneous but primarily peripheral enhancement patterns. Seven cases showed the polygon sign. In T1WI, the normal high signal intensity of neurohypophysis was absent from all patients, with no infundibular stalk thickening. Seven patients presented with optic chiasma edema, and 5 with edema-like changes along the optic tract (OTE), but most showed no visual impairment (n = 7). Magnetic resonance imaging, particularly postcontrast MRI, is the optimal modality for assessment of hypothalamic lesions. Peripheral enhancement with polygon sign and optic tract or chiasm edema without visual impairment are highly suggestive of hypothalamitis.

  9. A birdcage resonator for intracavitary MR imaging.

    PubMed

    Merchant, T E; Ballon, D; Koutcher, J A; Miodownik, S; Schwartz, L; Minsky, B D

    1993-01-01

    An intracavitary probe for magnetic resonance imaging of the pelvis has been developed that takes advantage of the "inside-out" spatial characteristics of a birdcage resonator. The probe consists of an eight-leg, birdcage resonator in a low-pass configuration operating in receive-only mode. The resonator circuit is mounted on a solid rod, is encased in Teflon, and has been used to obtain detailed images of pelvic anatomy in a male canine. The approximate cylindrical symmetry of the external sensitivity profile of this type of circuit, employed in an intracavitary application, demonstrates the potential superiority of this type of probe design over single-loop intracavitary coils. Axial, coronal, and sagittal MR images, obtained with 8 and 16 cm fields of view, are presented to illustrate the advantages of this type of intracavitary probe compared with conventional body-coil images. The prototype described in this report has been designed for clinical use in human subjects and is currently undergoing testing to determine its efficacy in the evaluation of rectal, prostate, and gynecologic pathology.

  10. Controlled drug release from an ocular implant: an evaluation using dynamic three-dimensional magnetic resonance imaging.

    PubMed

    Kim, Hyuncheol; Robinson, Michael R; Lizak, Martin J; Tansey, Ginger; Lutz, Robert J; Yuan, Peng; Wang, Nam S; Csaky, Karl G

    2004-08-01

    The ability of an episcleral implant at the equator of the eye to deliver drugs to the posterior segment was evaluated, using a sustained-release implant containing gadolinium-DTPA (Gd-DTPA). The movement of this drug surrogate was assessed with magnetic resonance imaging (MRI) in the rabbit eye. The results were compared with a similar implant placed in the vitreous cavity through a scleral incision at the equator. Polymer-based implants releasing Gd-DTPA were manufactured and placed in the subconjunctival space on the episclera or in the vitreous cavity in live rabbit eyes (in vivo) and in freshly enucleated eyes (ex vivo). Release rates of implants in vitro were also determined. Dynamic three-dimensional MRI was performed using a 4.7-Tesla MRI system for 8 hours. MR images were developed and analyzed on computer. Episcleral implants in vivo delivered a mean total of 2.7 microg Gd-DTPA into the vitreous, representing only 0.12% of the total amount of compound released from the implant in vitro. No Gd-DTPA was detected in the posterior segment of the eye. Ex vivo, the Gd-DTPA concentration in the vitreous was 30 times higher. In vivo eyes with intravitreal implants placed at the equator delivered Gd-DTPA throughout the vitreous cavity and posterior segment. Compartmental analysis of the ocular drug distribution from an episcleral implant showed that the elimination rate constant of Gd-DTPA from the subconjunctival space into the episcleral veins and conjunctival lymphatics was 3-log units higher than the transport rate constant for Gd-DTPA movement into the vitreous. In vivo, episcleral implants at the equator of the eye did not deliver a significant amount of Gd-DTPA into the vitreous, and no compound was identified in the posterior segment. A 30-fold increase in vitreous Gd-DTPA concentration occurred in the enucleated eyes, suggesting that there are significant barriers to the movement of drugs from the episcleral space into the vitreous in vivo. Dynamic three

  11. Functional cortical reorganization after low-frequency repetitive transcranial magnetic stimulation plus intensive occupational therapy for upper limb hemiparesis: evaluation by functional magnetic resonance imaging in poststroke patients.

    PubMed

    Yamada, Naoki; Kakuda, Wataru; Senoo, Atsushi; Kondo, Takahiro; Mitani, Sugao; Shimizu, Masato; Abo, Masahiro

    2013-08-01

    Low-frequency repetitive transcranial magnetic stimulation of the nonlesional hemisphere combined with occupational therapy significantly improves motor function of the affected upper limb in poststroke hemiparetic patients, but the recovery mechanism remains unclear. To investigate the recovery mechanism using functional magnetic resonance imaging. Forty-seven poststroke hemiparetic patients were hospitalized to receive 12 sessions of 40-min low-frequency repetitive transcranial magnetic stimulation over the nonlesional hemisphere and daily occupational therapy for 15 days. Motor function was evaluated with the Fugl-Meyer Assessment and Wolf Motor Function Test. The functional magnetic resonance imaging with motor tasks was performed at admission and discharge. The laterality index of activated voxel number in Brodmann areas 4 and 6 on functional magnetic resonance imaging was calculated (laterality index range of -1 to +1). Patients were divided into two groups based on functional magnetic resonance imaging findings before the intervention: group 1: patients who showed bilateral activation (n = 27); group 2: patients with unilateral activation (n = 20). Treatment resulted in improvement in Fugl-Meyer Assessment and Wolf Motor Function Test in the two groups (P < 0·01). The treatment also resulted in a significant increase in laterality index in group 1 (P < 0·05), suggesting a shift in activated voxels to the lesional hemisphere. Patients of group 2 showed a significant increase in lesional hemisphere activation (P < 0·05). The results of serial functional magnetic resonance imaging indicated that our proposed treatment can induce functional cortical reorganization, leading to motor functional recovery of the affected upper limb. Especially, it seems that neural activation in the lesional hemisphere plays an important role in such recovery in poststroke hemiparetic patients. © 2013 The Authors. International Journal of Stroke © 2013 World

  12. Magnetic resonance imaging in medicine

    NASA Astrophysics Data System (ADS)

    Keevil, Stephen F.

    2001-11-01

    Over the past twenty years, magnetic resonance imaging (MRI) has become one of the most important imaging modalities available to clinical medicine. It offers great technical flexibility, and is free of the hazards associated with ionizing radiation. In addition to its role as a routine imaging technique with a growing range of clinical applications, the pace of development in MRI methodology remains high, and new ideas with significant potential emerge on a regular basis. MRI is a prime example of the spin-off benefits of basic science, and is an area of medicine in which physical science continues to play a major role, both in supporting clinical applications and in developing new techniques. This article presents a brief history of MRI and an overview of the underlying physics, followed by a short survey of current and emerging clinical applications.

  13. Evaluation of Tricuspid Annular Plane Systolic Excursion Measured with Cardiac Magnetic Resonance Imaging in Pediatric Patients with Tetralogy of Fallot

    PubMed Central

    Soslow, Jonathan H.; Usoro, Emem; Wang, Li; Parra, David A.

    2015-01-01

    Background Aneurysmal dilation of the right ventricular outflow tract complicates assessment of right ventricular function in patients with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is commonly used to estimate ejection fraction. We hypothesized that tricuspid annular plane systolic excursion measured by cardiac magnetic resonance imaging approximates global and segmental right ventricular function, specifically right ventricular sinus ejection fraction, in pediatric patients with repaired tetralogy of Fallot. Methods Tricuspid annular plane systolic excursion was measured retrospectively on cardiac magnetic resonance images in 54 patients with repaired tetralogy of Fallot. Values were compared with right ventricular global, sinus, and infundibular ejection fractions. Tricuspid annular plane systolic excursion was: 1) indexed to body surface area, 2) converted into a fractional value, and 3) converted into published pediatric Z-scores. Results Tricuspid annular plane systolic excursion measurements had good agreement between observers. Right ventricular ejection fraction did not correlate with the absolute or indexed tricuspid annular plane systolic excursion and correlated weakly with fractional tricuspid annular plane systolic excursion (r=0.41 and p=0.002). Segmental right ventricular function did not appreciably improve correlation with any of the tricuspid annular plane systolic excursion measures. Pediatric Z-scores were unable to differentiate patients with normal and abnormal right ventricular function. Conclusions Tricuspid annular plane systolic excursion measured on cardiac magnetic resonance imaging correlates poorly with global and segmental right ventricular ejection fraction in pediatric patients with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is an unreliable approximation of right ventricular function in this patient population. PMID:26279488

  14. Design and Evaluation of a Planar Single-Channel Shim Coil for a Permanent Magnetic Resonance Imaging Magnet

    NASA Astrophysics Data System (ADS)

    Tamada, Daiki; Terada, Yasuhiko; Kose, Katsumi

    2011-06-01

    We propose a straightforward method of designing a planar single-channel shim coil for magnetic resonance imaging (MRI) using a narrow-gap permanent magnet. The design method is based on the superposition of the current densities produced by planar second-order shim coil elements and optimization of the coefficients used for the superposition. The magnetic field homogeneity was improved from 13 to 3.3 ppm (root mean square) in the central spherical area (diameter = 18 mm), revealing that the planar single-channel shim coil is a useful device for narrow-gap permanent MRI magnets.

  15. Evaluation of the efficacy of neoadjuvant chemotherapy for breast cancer using diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging.

    PubMed

    Xu, H D; Zhang, Y Q

    2017-01-01

    This study aims to investigate the predictive values of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in evaluating the efficacy of neoadjuvant chemotherapy (NAC) for breast cancer. Between September 2011 and December 2014, a total of 174 patients with locally advanced breast cancer treated with NAC were selected for this study. Conventional CT and MRI examinations (DWI and DCE-MRI) were performed in all patients before NAC (T0), after the first course (T1) and after the whole course (T2) of NAC. According to the response evaluation criteria in solid tumors (RECIST), patients were divided into the effective [complete response (CR) + partial response (PR)] and ineffective groups [stable disease (SD) + disease progression (DP)]. The Apparent diffusion coefficient (ADC), maximum tumor diameter, the early-phase enhancement rate (Ee), maximal enhanced rate of tumor (E max), maximal linear slope (S max), maximal excretion rate (E wash), signal intensity (SI), maximal signal rise velocity (V max) and area under the curve (AUC) of Cho before and after NAC were calculated. Receiver operating characteristic (ROC) curve was drawn and the AUC of change rate of ADC values and semi-quantitative parameter were utilized to analyze the diagnostic performance of them for evaluating the efficacy of NAC for breast cancer. There were 135 patients in the effective group, with 52 cases of CR and 83 cases of PR; 39 patients were in the ineffective group, with 14 cases of PD and 25 cases of SD. The effective rate of NAC for breast cancer was 77.6%. The ADC values of the two groups significantly increased but the maximum tumor diameter, E e, E max, S max, E wash and AUC of Cho greatly decreased. The effective group had higher ADC values, its change rate and tumor regression rate than the ineffective group. However, the maximum tumor diameter, E e, E max, S max, E wash, AUC of Cho, SI and V max in the effective group were remarkably lower

  16. Evaluation of different magnetic resonance imaging contrast materials to be used as dummy markers in image-guided brachytherapy for gynecologic malignancies*

    PubMed Central

    Sales, Camila Pessoa; Carvalho, Heloisa de Andrade; Taverna, Khallil Chaim; Pastorello, Bruno Fraccini; Rubo, Rodrigo Augusto; Borgonovi, Arthur Felipe; Stuart, Silvia Radwanski; Rodrigues, Laura Natal

    2016-01-01

    Objective To identify a contrast material that could be used as a dummy marker for magnetic resonance imaging. Materials and Methods Magnetic resonance images were acquired with six different catheter-filling materials-water, glucose 50%, saline, olive oil, glycerin, and copper sulfate (CuSO4) water solution (2.08 g/L)-inserted into compatible computed tomography/magnetic resonance imaging ring applicators placed in a phantom made of gelatin and CuSO4. The best contrast media were tested in four patients with the applicators in place. Results In T2-weighted sequences, the best contrast was achieved with the CuSO4-filled catheters, followed by saline- and glycerin-filled catheters, which presented poor visualization. In addition (also in T2-weighted sequences), CuSO4 presented better contrast when tested in the phantom than when tested in the patients, in which it provided some contrast but with poor identification of the first dwell position, mainly in the ring. Conclusion We found CuSO4 to be the best solution for visualization of the applicator channels, mainly in T2-weighted images in vitro, although the materials tested presented low signal intensity in the images obtained in vivo, as well as poor precision in determining the first dwell position. PMID:27403016

  17. An evaluation of JPEG and JPEG 2000 irreversible compression algorithms applied to neurologic computed tomography and magnetic resonance images. Joint Photographic Experts Group.

    PubMed

    Savcenko, V; Erickson, B J; Persons, K R; Campeau, N G; Huston, J; Wood, C P; Schreiner, S A

    2000-05-01

    We performed visual comparison of 200 head magnetic resonance (MR) and 200 head computed tomography (CT) images compressed at two levels using standard Joint Photographic Experts Group (JPEG) irreversible compression and a preliminary version of the JPEG 2000 irreversible algorithm. Blinded evaluations by neuroradiologists compared original versus either JPEG or JPEG 2000. We found that this version of JPEG 2000 did not perform as well as the current JPEG for head CTs, but for MR images, JPEG 2000 performed as well or better. Around 7:1 compression ratio seemed to be a conservative point where there was no perceptible difference.

  18. Maximum intensity projection with magnetic resonance imaging for evaluating synovitis of the hand in rheumatoid arthritis: comparison with clinical and ultrasound findings.

    PubMed

    Taniguchi, Daigo; Tokunaga, Daisaku; Oda, Ryo; Fujiwara, Hiroyoshi; Ikeda, Takumi; Ikoma, Kazuya; Kishida, Aiko; Yamasaki, Tetsuro; Kawahito, Yutaka; Seno, Takahiro; Ito, Hirotoshi; Kubo, Toshikazu

    2014-07-01

    Magnetic resonance imaging (MRI) with maximum intensity projection (MIP) is used to evaluate the hand in rheumatoid arthritis (RA). MIP yields clear visualization of synovitis over the entirety of the bilateral hands with a single image. In this study, we assessed synovitis with MIP images, clinical findings, and power Doppler (PD) findings to examine the clinical usefulness of MIP images for RA in the hand. Thirty RA patients were assessed for swelling and tenderness in the joints included in the DAS28, and both contrast-enhanced MRI for bilateral hands and ultrasonography for bilateral wrist and metacarpophalangeal (MCP) joints were performed. Articular synovitis was scored in MIP images, and the scores were compared with those for PD. The agreement on synovitis between MIP and conventional MR images was excellent. Palpation showed low sensitivity and high specificity compared with both MIP and PD images. There were joints that were positive in MIP images only, but there were no joints that were positive in PD images only. A statistically significant correlation between the scores of MIP and PD images was found. Furthermore, the agreement between grade 2 on MIP images and positive on PD images was 0.87 (κ = 0.73) for the wrist and 0.92 (κ = 0.57) for MCP joints. Using MIP images together with palpation makes detailed evaluation of synovitis of the hand in RA easy. MIP images may predict further joint damage, since they allow semiquantitative estimation of the degree of thickening of the synovial membrane.

  19. Magnetic resonance imaging of optic nerve

    PubMed Central

    Gala, Foram

    2015-01-01

    Optic nerves are the second pair of cranial nerves and are unique as they represent an extension of the central nervous system. Apart from clinical and ophthalmoscopic evaluation, imaging, especially magnetic resonance imaging (MRI), plays an important role in the complete evaluation of optic nerve and the entire visual pathway. In this pictorial essay, the authors describe segmental anatomy of the optic nerve and review the imaging findings of various conditions affecting the optic nerves. MRI allows excellent depiction of the intricate anatomy of optic nerves due to its excellent soft tissue contrast without exposure to ionizing radiation, better delineation of the entire visual pathway, and accurate evaluation of associated intracranial pathologies. PMID:26752822

  20. Evaluation of suspected soft tissue lesion in the prostate bed after radical prostatectomy using 3T multiparametric magnetic resonance imaging.

    PubMed

    Cha, Dongik; Kim, Chan Kyo; Park, Sung Yoon; Park, Jung Jae; Park, Byung Kwan

    2015-05-01

    To investigate the usefulness of multiparametric MR imaging (mp-MRI) at 3T for evaluating suspected soft tissue lesion in the prostate bed after radical prostatectomy (RP). Forty-three patients with biochemical recurrence (BCR) who received RP underwent mp-MRI at 3T with a phased-array coil, including T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI) and dynamic contrast-enhanced imaging (DCE-MRI) and were enrolled in this study. All patients with BCR had a suspected soft tissue lesion in the prostate bed, followed by transrectal ultrasound-guided biopsy. As a control group, 14 consecutive patients without BCR who received RP were also enrolled. Two experienced radiologists independently analyzed four different imaging datasets. For predicting local recurrence, the specificity, accuracy and area under the curve for both readers were significantly greater on all combined imaging datasets than on T2WI alone (P<0.05). The sensitivity of all combined imaging datasets in both readers was not statistically different with T2WI alone (P>0.05), except for combined T2WI and DWI. Inter-reader agreements for the four different imaging datasets were moderate. DCE-MRI or DWI in combination with T2WI at 3T with a phased-array coil appears to be more useful than T2WI alone in evaluating suspected soft tissue lesion of the prostate bed after RP. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Feasibility of magnetic resonance electrical impedance tomography (MREIT) conductivity imaging to evaluate brain abscess lesion: in vivo canine model.

    PubMed

    Oh, Tong In; Jeong, Woo Chul; McEwan, Alistair; Park, Hee Myung; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2013-07-01

    To show the feasibility of magnetic resonance electrical impedance tomography (MREIT) conductivity imaging in terms of its capability to provide new contrast information of abscess lesion and characterize time-course variations before and after the induction of brain abscess. Brain abscess was induced in healthy beagles by a direct inoculation method using Staphylococcus pseudintermedius. After the induction, four electrodes were attached on the head and the dog was placed inside the magnetic resonance imaging (MRI) bore. Using a current source, we injected a current of amplitude 5 mA and a pulse width of 81 msec. A multi-echo ICNE pulse sequence was used to obtain the magnetic flux density (Bz ) data. The relative conductivity contrast ratios (rCCR, %) of abscess lesion were significantly changed by the postinduction time (P < 0.01). The rCCRs of central abscess lesions were higher than the surrounding area at 6, 12, and 18 hours (P < 0.01). Over 12 hours, the relationship between the induction time and rCCR showed a positive correlation followed by a negative correlation (P < 0.01). We performed in vivo disease model animal experiments to validate the MREIT technique providing conductivity information of tissues in situ to be utilized in clinical applications. Copyright © 2012 Wiley Periodicals, Inc.

  2. Functional magnetic resonance imaging evaluation of brain function reorganization in cerebral stroke patients after constraint-induced movement therapy.

    PubMed

    Zhao, Jun; Zhang, Tong; Xu, Jianmin; Wang, Mingli; Zhao, Shengjie

    2012-05-25

    In this study, stroke patients received constraint-induced movement therapy for 3 weeks. Before and after constraint-induced movement therapy, the flexibility of their upper limbs on the affected side was assessed using the Wolf motor function test, and daily use of their affected limbs was assessed using the movement activities log, and cerebral functional reorganization was assessed by functional magnetic resonance imaging. The Wolf motor function test score and the movement activities log quantity and quality scores were significantly increased, while action performance time in the Wolf motor function test was significantly decreased after constraint-induced movement therapy. By functional magnetic resonance imaging examination, only scattered activation points were visible on the affected side before therapy. In contrast, the volume of the activated area was increased after therapy. The activation volume in the sensorimotor area was significantly different before and after therapy, and the activation area increased and appeared adjusted. In addition to the activated area around the lesions being decreased, there were also some new activated areas, including the supplementary movement area, premotor area and the ipsilateral sensorimotor area. Our findings indicate that constraint-induced movement therapy significantly improves the movement ability and daily use of the affected upper limbs in stroke patients and promotes cerebral functional reorganization.

  3. Uterus and ovaries in girls and young women with Turner syndrome evaluated by ultrasound and magnetic resonance imaging.

    PubMed

    Cleemann, Line; Holm, Kirsten; Fallentin, Eva; Skouby, Svend Oluf; Smedegaard, Heidi; Møller, Nini; Borch-Christensen, Hanne; Jeppesen, Eva Mosfeldt; Wieslander, Steen Bo; Andersson, Anna-Maria; Cohen, Arieh; Højbjerg Gravholt, Claus

    2011-06-01

    To determine uterine and ovarian size in Turner syndrome (TS) and to compare uterine and ovarian size evaluated by transabdominal ultrasound (US) and magnetic resonance imaging (MRI) in girls with TS and two groups of controls. A cross-sectional study. Forty-one girls with TS (17·0 ± 3·3 years, range 11·2-24·9 years), 50 healthy age-matched controls (16·9 ± 3·2 years, range 12·5-25·0 years) and 107 Tanner-stage-matched controls (15·0 ± 3·2 years, range 10·1-24·2). Uterine and ovarian volume by US and MRI. Ovaries were detected in 37% in TS by US and in 55% in TS by MRI (P = 0·1). Total ovarian volume was lower in TS compared to both groups of controls (TS vs C-US: median 1·1 ml (range 0·1-29·3) vs 11·52 ml (1·9-77·9), P = 0·001, TS vs C-MRI: 1·0 ml (0·1-34·2) vs 13·2 ml (2·4-30·1), P < 0·0005). Mean difference in total ovarian volume measured by MRI and US in patients with TS was 2·3 ± 3·8 ml (P = 0·01). Mean uterine volume by MRI was lower in TS compared to controls (29·5 ± 25·1 vs 54·3 ± 23·3 ml, P < 0·0005). Uterine volume by US was lower in TS at Tanner stage B5 compared to controls (TS vs C: 33·6 ± 18·2 vs 50·2 ± 18·0 ml, P = 0·007). A larger ovarian volume was detected by MRI in TS compared to US. This finding is important with the advancements of performing ovarian biopsies for cryopreservation and later reimplantation. Mean uterine volumes by MRI and US in fully matured TS were lower compared to controls despite appropriate hormonal replacement therapy in TS. © 2011 Blackwell Publishing Ltd.

  4. Evaluation of Bound and Pore Water in Cortical Bone Using Ultrashort Echo Time (UTE) Magnetic Resonance Imaging

    PubMed Central

    Shao, Hongda; D'Lima, Darryl; Bydder, Graeme M; Wu, Zhihong; Du, Jiang

    2015-01-01

    Bone water exists in different states with the majority bound to the organic matrix and to mineral, and a smaller fraction in ‘free’ form in the pores of cortical bone. In this study we aimed to develop and evaluate ultrashort echo time (UTE) magnetic resonance imaging (MRI) techniques for assessment of T2*, T1 and concentration of collagen-bound and pore water in cortical bone using a 3T clinical whole-body scanner. UTE MRI together with an isotope study using tritiated and distilled water (THO-H2O) exchange as well as gravimetrical analysis were performed on ten sectioned bovine bone samples. In addition, 32 human cortical bone samples were prepared for comparison between pore water concentration measured with UTE MRI and cortical porosity derived from micro computed tomography (μCT). A short T2* of 0.27 ± 0.03 ms and T1 of 116±6 ms were observed for collagen-bound water in bovine bone. A longer T2* of 1.84 ± 0.52 ms and T1 of 527±28 ms were observed for pore water in bovine bone. UTE MRI measurements showed a pore water concentration of 4.7-5.3% by volume and collagen-bound water concentration of 15.7-17.9% in bovine bone. THO-H2O exchange studies showed a pore water concentration of 5.9 ± 0.6% and collagen-bound water concentration of 18.1 ± 2.1% in bovine bone. Gravimetrical analysis showed a pore water concentration of 6.3 ± 0.8% and collagen-bound water concentration of 19.2 ± 3.6% in bovine bone. A mineral water concentration of 9.5 ± 0.6% was derived in bovine bone with the THO-H2O exchange study. UTE measured pore water concentration is highly correlated (R2 = 0.72, P < 0.0001) with μCT porosity in the human cortical bone study. Both bovine and human bone studies suggest that UTE sequences could reliably measure collagen-bound and pore water concentration in cortical bone using a clinical scanner. PMID:26527298

  5. Evaluation of the Prostate Imaging Reporting and Data System for Magnetic Resonance Imaging Diagnosis of Prostate Cancer in Patients with Prostate-specific Antigen <20 ng/ml

    PubMed Central

    Wang, Xuan; Wang, Jian-Ye; Li, Chun-Mei; Zhang, Ya-Qun; Wang, Jian-Long; Wan, Ben; Zhang, Wei; Chen, Min; Li, Sa-Ying; Wan, Gang; Liu, Ming

    2016-01-01

    Background: The European Society of Urogenital Radiology has built the Prostate Imaging Reporting and Data System (PI-RADS) for standardizing the diagnosis of prostate cancer (PCa). This study evaluated the PI-RADS diagnosis method in patients with prostate-specific antigen (PSA) <20 ng/ml. Methods: A total of 133 patients with PSA <20 ng/ml were prospectively recruited. T2-weighted (T2WI) and diffusion-weighted (DWI) magnetic resonance images of the prostate were acquired before a 12-core transrectal prostate biopsy. Each patient's peripheral zone was divided into six regions on the images; each region corresponded to two of the 12 biopsy cores. T2WI, DWI, and T2WI + DWI scores were computed according to PI-RADS. The diagnostic accuracy of the PI-RADS score was evaluated using histopathology of prostate biopsies as the reference standard. Results: PCa was histologically diagnosed in 169 (21.2%) regions. Increased PI-RADS score correlated positively with increased cancer detection rate. The cancer detection rate for scores 1 to 5 was 2.8%, 15.0%, 34.6%, 52.6%, and 88.9%, respectively, using T2WI and 12.0%, 20.2%, 48.0%, 85.7%, and 93.3%, respectively, using DWI. For T2WI + DWI, the cancer detection rate was 1.5% (score 2), 13.5% (scores 3–4), 41.3% (scores 5–6), 75.9% (scores 7–8), and 92.3% (scores 9–10). The area under the curve for cancer detection was 0.700 (T2WI), 0.735 (DWI) and 0.749 (T2WI + DWI). The sensitivity and specificity were 53.8% and 89.2%, respectively, when using scores 5–6 as the cutoff value for T2WI + DWI. Conclusions: The PI-RADS score correlates with the PCa detection rate in patients with PSA <20 ng/ml. The summed score of T2WI + DWI has the highest accuracy in detection of PCa. However, the sensitivity should be further improved. PMID:27270538

  6. Advanced MR imaging techniques in the evaluation of nonenhancing gliomas: perfusion-weighted imaging compared with proton magnetic resonance spectroscopy and tumor grade.

    PubMed

    Sahin, Neslin; Melhem, Elias R; Wang, Sumei; Krejza, Jaroslaw; Poptani, Harish; Chawla, Sanjeev; Verma, Gaurav

    2013-10-01

    A significant number of nonenhancing (NE) gliomas are reported to be malignant. The purpose of this study was to compare the value of advanced MR imaging techniques, including T2*-dynamic susceptibility contrast PWI (DSC-PWI) and proton magnetic resonance spectroscopy ((1)HMRS) in the evaluation of NE gliomas. Twenty patients with NE gliomas underwent MRI including DSC-PWI and (1)HMRS. The relative CBV (rCBV) measurements were obtained from regions of maximum perfusion. The peak ratios of choline/creatine (Cho/Cr) and myo-inositol/creatine (mIns/Cr) were measured at a TE of 30 ms. Demographic features, tumor volumes, and PWI- and (1)HMRS-derived measures were compared between low-grade gliomas (LGGs) and high-grade gliomas (HGGs). In addition, the association of initial rCBV ratio with tumor progression was evaluated in LGGs. No significant difference was noted in age, sex or tumor size between LGGs and HGGs. Cho/Cr ratios were significantly higher in HGGs (1.7±0.63) than in LGGs (1.2±0.38). The receiver operating characteristic analysis demonstrated that a Cho/Cr ratio with a cutoff value of 1.3 could differentiate between LGG and HGG with a specificity of 100% and a sensitivity of 71.4%. There was no significant difference in the rCBV ratio and the mIns/Cr ratio between LGG and HGG. However, higher rCBV ratios were observed with more rapid progressions in LGGs. The results imply that Cho/Cr ratios are useful in distinguishing NE LGG from HGG and can be helpful in preoperative grading and biopsy guidance. On the other hand, rCBV ratios do not help in the distinction.

  7. [Presurgical functional magnetic resonance imaging].

    PubMed

    Stippich, C

    2010-02-01

    Functional magnetic resonance imaging (fMRI) is an important and novel neuroimaging modality for patients with brain tumors. By non-invasive measurement, localization and lateralization of brain activiation, most importantly of motor and speech function, fMRI facilitates the selection of the most appropriate and sparing treatment and function-preserving surgery. Prerequisites for the diagnostic use of fMRI are the application of dedicated clinical imaging protocols and standardization of the respective imaging procedures. The combination with diffusion tensor imaging (DTI) also enables tracking and visualization of important fiber bundles such as the pyramidal tract and the arcuate fascicle. These multimodal MR data can be implemented in computer systems for functional neuronavigation or radiation treatment. The practicability, accuracy and reliability of presurgical fMRI have been validated by large numbers of published data. However, fMRI cannot be considered as a fully established modality of diagnostic neuroimaging due to the lack of guidelines of the responsible medical associations as well as the lack of medical certification of important hardware and software components. This article reviews the current research in the field and provides practical information relevant for presurgical fMRI.

  8. Near field imaging with resonant cavity lens.

    PubMed

    Li, Guixin; Li, Jensen; Tam, H L; Chan, C T; Cheah, K W

    2010-02-01

    We showed that a Ag-SiO(2)-Ag Fabry-Pérot cavity can be used in near-field imaging based on omnidirectional resonance tunneling. The omnidirectional resonance was experimentally demonstrated in the Ag-SiO(2)-Ag resonant cavity working at a wavelength of 365 nm. The resonant cavity lens with high transmittance and high image fidelity was fabricated using standard photolithography method. Grating source with 190 nm line resolution was imaged through the resonant cavity lens with a total thickness of 128 nm.

  9. Chest magnetic resonance imaging: a protocol suggestion*

    PubMed Central

    Hochhegger, Bruno; de Souza, Vinícius Valério Silveira; Marchiori, Edson; Irion, Klaus Loureiro; Souza Jr., Arthur Soares; Elias Junior, Jorge; Rodrigues, Rosana Souza; Barreto, Miriam Menna; Escuissato, Dante Luiz; Mançano, Alexandre Dias; Araujo Neto, César Augusto; Guimarães, Marcos Duarte; Nin, Carlos Schuler; Santos, Marcel Koenigkam; Silva, Jorge Luiz Pereira e

    2015-01-01

    In the recent years, with the development of ultrafast sequences, magnetic resonance imaging (MRI) has been established as a valuable diagnostic modality in body imaging. Because of improvements in speed and image quality, MRI is now ready for routine clinical use also in the study of pulmonary diseases. The main advantage of MRI of the lungs is its unique combination of morphological and functional assessment in a single imaging session. In this article, the authors review most technical aspects and suggest a protocol for performing chest MRI. The authors also describe the three major clinical indications for MRI of the lungs: staging of lung tumors; evaluation of pulmonary vascular diseases; and investigation of pulmonary abnormalities in patients who should not be exposed to radiation. PMID:26811555

  10. Evaluation of reperfused myocardial infarction by low-dose multidetector computed tomography using prospective electrocardiography (ECG)-triggering: comparison with magnetic resonance imaging.

    PubMed

    Gweon, Hye Mi; Kim, Sang Jin; Kim, Tae Hoon; Lee, Sang Min; Hong, Yoo Jin; Rim, Se-Joong; Hong, Bum Ki; Min, Phil Ki; Yoon, Young Won; Kwon, Hyuck Moon

    2010-09-01

    To evaluate the potential of prospective electrocardiography (ECG)- gated 64-slice multidetector computed tomography (MDCT) for evaluation of myocardial enhancement, infarct size, and stent patency after percutaneous coronary intervention (PCI) with stenting in patients with myocardial infarction. Seventeen patients who were admitted with acute myocardial infarction were examined with prospective ECG-gated 64-slice cardiac MDCT and magnetic resonance (MR) imaging after reperfusion using PCI with stenting. Cardiac MDCT was performed with two different phases: arterial and delayed phases. We evaluated the stent patency on the arterial phase, and nonviable myocardium on the delayed phase of computed tomography (CT) image, and they were compared with the results from the delayed MR images. Total mean radiation dose was 7.7 +/- 0.5 mSv on the two phases of CT images. All patients except one showed good patency of the stent at the culprit lesion on the arterial phase CT images. All patients had hyperenhanced area on the delayed phase CT images, which correlated well with those on the delayed phase MR images, with a mean difference of 1.6% (20 +/- 10% vs. 22 +/- 10%, r = 0.935, p = 0.10). Delayed MR images had a better contrast-to-noise ratio (CNR) than delayed CT images (27.1 +/- 17.8% vs. 4.3 +/- 2.1%, p < 0.001). Prospective ECG-gated 64-slice MDCT provides the potential to evaluate myocardial viability on delayed phase as well as for stent patency on arterial phase with an acceptable radiation dose after PCI with stenting in patients with myocardial infarction.

  11. Rare bilateral C6 spondylolysis and spondylolisthesis in an adolescent athlete: evaluation with magnetic resonance imaging and multidetector computerized tomography.

    PubMed

    Amin, Mohammed F; Mollano, Anthony V; Weinstein, Stuart L; El-Khoury, George Y

    2006-10-01

    Case report. To show a rare case of cervical spondylolysis and spondylolisthesis secondary to bilateral stress fractures at the pedicle laminar junction of C6 in a 16-year-old athlete playing high school baseball. The patient presented with 3 months of neck pain and intermittent right arm radicular symptoms. Plain radiographs and multidetector computerized tomography (CT) of the cervical spines. Plain radiographs revealed loss of lower cervical lordosis. Multidetector CT indicated bilateral C6 spondylolysis. Magnetic resonance imaging showed bilateral marrow edema at the pedicle laminar junction of C6. Treatment included placing his neck in a Philadelphia collar for 6 weeks. Follow-up CT revealed progression of healing. Early diagnosis and appropriate management of these cases are important to promote healing.

  12. Rationale and design of the carotid plaque in human for all evaluations with aggressive rosuvastatin therapy (CHALLENGER trial): evaluation by magnetic resonance imaging.

    PubMed

    Miyauchi, Katsumi; Takaya, Norihide; Hirose, Takahisa; Ikeda, Fuki; Kawamori, Ryuzo; Ohishi, Hidenori; Yoshida, Kensaku; Yamamoto, Munetaka; Arai, Hajime; Urabe, Takao; Hattori, Nobutaka; Suzuki, Michimasa; Maehara, Tadayuki; Sase, Kazuhiro; Hatsukami, Thomas S; Yuan, Chun; Daida, Hiroyuki

    2009-01-01

    Intensive lipid-lowering therapy with statins reduces levels of low-density lipoprotein (LDL)-cholesterol (C) and improves plaque volume and composition in patients with cardiovascular disease. Furthermore, rosuvastatin ameliorated carotid stenosis in the ASTEROID study, and altered the composition of plaques in a predominantly Caucasian study population in the ORION study. However, it is not known whether statin therapy achieves similar quantitative improvement in carotid artery plaque in other ethnic groups. Fifty patients with hypercholesterolemia (LDL-C >or=120 mg/dl) and a maximum carotid intima-media thickness >or=1.8 mm will be enrolled and treated with rosuvastatin at a dose of 5 mg/day for 96 weeks. The primary endpoints will be the percent change of carotid plaque volume and the change in plaque composition after 96 weeks of treatment, as evaluated by magnetic resonance imaging. The CHALLENGER study will provide a noninvasive assessment of the changes in carotid plaque volume and composition achieved by reduction of LDL levels in Japanese patients with carotid stenosis on long-term rosuvastatin therapy.

  13. Off-resonance frequency filtered magnetic resonance imaging.

    PubMed

    Medic, Jure; Tomazic, Saso

    2010-05-01

    One of the main problems with rapid magnetic resonance imaging (MRI) techniques is the artifacts that result from off-resonance effects. The proposed off-resonance frequency filtered MRI (OFF-MRI) method focuses on the elimination of off-resonance components from the image of the observed object. To maintain imaging speed and simultaneously achieve good frequency selectivity, MRI is divided into two steps: signal acquisition and post-processing. After the preliminary phase in which we determine imaging parameters, MRI takes place; the signal from the same object is successively acquired M times. As a result, we obtain M partial signals in k-space, from which we form the image of the observed object in the post-processing phase, after signal acquisition has been completed. This paper demonstrates that with proper selection of acquisition parameters and weighting coefficients in the post-processing phase, OFF-MRI is equivalent to filtering the signal by finite impulse response filter of length M. It is shown that with M successive acquisitions M-1 off-resonance components can be eliminated (filtered-out) from images, and therefore, only two acquisitions are needed to eliminate one off-resonance components. On the other hand, with OFF-MRI, it is also possible to form the image of an arbitrary off-resonance component by eliminating all other off-resonance components, including the on-resonance component. The proposed OFF-MRI method is suitable for MRI where rapid acquisition is required and elimination of off-resonance components can improve reliability of measurements. 2010 Elsevier Inc. All rights reserved.

  14. Colloidal amphiphile self-assembly particles composed of gadolinium oleate and myverol: evaluation as contrast agents for magnetic resonance imaging.

    PubMed

    Liu, Guozhen; Conn, Charlotte E; Waddington, Lynne J; Mudie, Stephen T; Drummond, Calum J

    2010-02-16

    Gadolinium oleate has been added at various concentrations to a Myverol inverse bicontinuous cubic phase forming system, and the potential of these systems as magnetic resonance imaging (MRI) contrast agents has been investigated. Differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), and cryo-transmission electron microscopy (cryo-TEM) measurements on the Gd oleate/Myverol systems indicate that Gd oleate is at least partially incorporated within the cubic phase of Myverol. However, at Gd oleate concentrations greater than 1 wt %, partial phase separation of the system may occur with the formation of a Gd-oleate-rich lamellar phase as well as the cubic phase. Bulk Gd oleate/Myverol mixtures can be dispersed into stable colloidal dispersions. SAXS and cryo-TEM measurements on these dispersions indicate that the presence of Gd oleate in the Myverol system prevents the formation of cubosomes from the bulk cubic phase. Instead, the dispersion consists of putative Gd-oleate-rich nonswelling lamellar nanoparticles as well as colloidal particles lacking ordered internal structure. In vitro studies on these dispersions demonstrated that the relaxivity of select Gd oleate/Myverol systems is much higher than that of pure Gd oleate, exemplifying the promise of this system type for magnetic resonance imaging. The highest water proton relaxivities (r(1) = 34.2 mM(-1) s(-1) and r(2) = 27.3 mM(-1) s(-1) at 20 MHz and room temperature) were obtained at a Gd oleate loading concentration of 1 wt %, with a subsequent decrease in relaxivity with increasing Gd oleate concentration. These maximum relaxivities compare favorably with the relaxivities for the commercial contrast agent, Magnevist (r(1) = 4.91 mM(-1) s(-1) and r(2) = 6.26 mM(-1) s(-1) at 20 MHz and room temperature).

  15. Magnetic resonance imaging of the temporomandibular joint.

    PubMed

    Hayt, M W; Abrahams, J J; Blair, J

    2000-04-01

    The spectrum of disease that affects the temporomandibular joint (TMJ) can be varied. To differentiate among the diseases that cause pain and dysfunction, an intimate knowledge of the anatomy, physiology, and pathology of this region is necessary. Due to the joint's complex anatomy and relationship to the skin, it has been difficult to image in the past. Magnetic resonance imaging is ideally suited for visualizing TMJ because of its superb contrast resolution when imaging soft tissues. Magnetic resonance imaging allows simultaneous bilateral visualization of both joints. The ability to noninvasively resolve anatomic detail can be performed easily and quickly using magnetic resonance imaging. The development of magnetic resonance imaging has greatly aided the diagnosis of TMJ disorders. An understanding of TMJ anatomy and pathogenesis of TMJ pain is crucial for interpretation of magnetic resonance imaging and subsequent treatment.

  16. Magnetic resonance imaging: Principles and applications

    SciTech Connect

    Kean, D.; Smith, M.

    1986-01-01

    This text covers the physics underlying magnetic resonance (MR) imaging; pulse sequences; image production; equipment; aspects of clinical imaging; and the imaging of the head and neck, thorax, abdomen and pelvis, and musculoskeletal system; and MR imaging. The book provides about 150 examples of MR images that give an overview of the pathologic conditions imaged. There is a discussion of the physics of MR imaging and also on the spin echo.

  17. Evaluation of the WARP-turbo spin echo sequence for 3 Tesla magnetic resonance imaging of stifle joints in dogs with stainless steel tibial plateau leveling osteotomy implants.

    PubMed

    Simpler, Renee E; Kerwin, Sharon C; Eichelberger, Bunita M; Wall, Corey R; Thompson, James A; Padua, Abraham; Purdy, David; Griffin, John F

    2014-01-01

    Susceptibility artifacts caused by ferromagnetic implants compromise magnetic resonance imaging (MRI) of the canine stifle after tibial plateau leveling osteotomy (TPLO) procedures. The WARP-turbo spin echo sequence is being developed to mitigate artifacts and utilizes slice encoding for metal artifact reduction. The aim of the current study was to evaluate the WARP-turbo spin echo sequence for imaging post TPLO canine stifle joints. Proton density weighted images of 19 canine cadaver limbs were made post TPLO using a 3 Tesla MRI scanner. Susceptibility artifact sizes were recorded and compared for WARP vs. conventional turbo spin echo sequences. Three evaluators graded depiction quality for the tibial tuberosity, medial and lateral menisci, tibial osteotomy, and caudal cruciate ligament as sufficient or insufficient to make a diagnosis. Artifacts were subjectively smaller and local structures were better depicted in WARP-turbo spin echo images. Signal void area was also reduced by 75% (sagittal) and 49% (dorsal) in WARP vs. conventional turbo spin echo images. Evaluators were significantly more likely to grade local anatomy depiction as adequate for making a diagnosis in WARP-turbo spin echo images in the sagittal but not dorsal plane. The proportion of image sets with anatomic structure depiction graded adequate to make a diagnosis ranged from 28 to 68% in sagittal WARP-turbo spin echo images compared to 0-19% in turbo spin echo images. Findings indicated that the WARP-turbo spin echo sequence reduces the severity of susceptibility artifacts in canine stifle joints post TPLO. However, variable depiction of local anatomy warrants further refinement of the technique.

  18. Functional Magnetic Resonance Imaging Methods

    PubMed Central

    Chen, Jingyuan E.; Glover, Gary H.

    2015-01-01

    Since its inception in 1992, Functional Magnetic Resonance Imaging (fMRI) has become an indispensible tool for studying cognition in both the healthy and dysfunctional brain. FMRI monitors changes in the oxygenation of brain tissue resulting from altered metabolism consequent to a task-based evoked neural response or from spontaneous fluctuations in neural activity in the absence of conscious mentation (the “resting state”). Task-based studies have revealed neural correlates of a large number of important cognitive processes, while fMRI studies performed in the resting state have demonstrated brain-wide networks that result from brain regions with synchronized, apparently spontaneous activity. In this article, we review the methods used to acquire and analyze fMRI signals. PMID:26248581

  19. Synthesis and systematic evaluation of dark resonance energy transfer (DRET)-based library and its application in cell imaging.

    PubMed

    Su, Dongdong; Teoh, Chai Lean; Kang, Nam-Young; Yu, Xiaotong; Sahu, Srikanta; Chang, Young-Tae

    2015-03-01

    In this paper, we report a new strategy for constructing a dye library with large Stokes shifts. By coupling a dark donor with BODIPY acceptors of tunable high quantum yield, a novel dark resonance energy transfer (DRET)-based library, named BNM, has been synthesized. Upon excitation of the dark donor (BDN) at 490 nm, the absorbed energy is transferred to the acceptor (BDM) with high efficiency, which was tunable in a broad range from 557 nm to 716 nm, with a high quantum yield of up to 0.8. It is noteworthy to mention that the majority of the non-radiative energy loss of the donor was converted into the acceptor's fluorescence output with a minimum leak of donor emission. Fluorescence imaging tested in live cells showed that the BNM compounds are cell-permeable and can also be employed for live-cell imaging. This is a new library which can be excited through a dark donor allowing for strong fluorescence emission in a wide range of wavelengths. Thus, the BNM library is well suited for high-throughput screening or multiplex experiments in biological applications by using a single laser excitation source. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. [Evaluation of left ventricular function with a 16-slice multidetector tomograph (MDCT-16): correlation with cardiovascular magnetic resonance imaging].

    PubMed

    de la Peña-Almaguer, Erasmo; Azpiri López, José Ramón; González-Camid, Felipe de Jesús; Ponce de León, Enrique; Flores-Ramírez, Ramiro; Zamarripa, Rafael; Loera, Javier; Rodríguez, Daniel; González Quijano, Rafael; Azpiri-Magallanes, Marcela; Jaramillo Estrada, Samuel; Assad Morell, José Luis

    2005-01-01

    The evaluation of Left ventricular function has both prognostic as well as therapeutic implications in patients with heart disease. Non-invasive coronary angiography with computed tomography using 16 slices (MDCT-16) allows to obtain images of the coronary anatomy due to its high spatial and temporal resolution, and also, to obtain data regarding Left ventricular function. The objective of this study was to correlate the use of MDCT-16 for the evaluation of the Left ventricular parameters using MRI as the Standard of reference. MRI: Se A 1.5 Tesla GE CvI Scanner optimized for cardiovascular applications was used. Using an ECG gated steady state fast precession sequence (SSFP, Thickness 10 mm, Flip Angle 45, FOV 36 cm. NEX 1, Frequency 256, Phase 128, Partial FOV 0.75, 16VPS), 6 to 8 short axis images of from base to apex of the left ventricle were obtained. Tomography: Using a 16 slice Multidetector tomograph (GE Lightspeed) and using ECG synchronization, images of the heart were obtained after the administration of 80 mls. of no-ionic contrast. The images were reconstructed off-line to obtain from 6 to 8 slices in a similar fashion to that of MR. Both studies were independently analyzed by 2 operators who obtained the ventricular function data. Linear correlation and a Paired T Student test was used to analyze the data and was considered significant when p < 0.05. 20 consecutive patients were evaluated with MDCT-16 and MRI, 18 males, mean age 52 +/- 15 years. There was no significant difference among the measurements for cardiac CT and MRI of the end-diastolic volume (EDV) and end-sistolic volume (ESV), stroke volume (SV), LV Mass or LV ejection fraction (LVEF). This results show a high correlation among the clinically relevant ventricular function parameters evaluated by cardiovascular CT and MRI. This findings suggest that ventricular function can be successfully evaluated along with the coronary anatomy using MDCT-16.

  1. Pocket atlas of cranial magnetic resonance imaging

    SciTech Connect

    Haughton, V.M.; Daniels, D.L.

    1986-01-01

    This atlas illustrates normal cerebral anatomy in magnetic resonance images. From their studies in cerebral anatomy utilizing cryomicrotome and other techniques, the authors selected more than 100 high-resolution images that represent the most clinically useful scans.

  2. Magnetic Resonance Imaging Allows the Evaluation of Tissue Damage and Regeneration in a Mouse Model of Critical Limb Ischemia.

    PubMed

    Zaccagnini, Germana; Palmisano, Anna; Canu, Tamara; Maimone, Biagina; Lo Russo, Francesco M; Ambrogi, Federico; Gaetano, Carlo; De Cobelli, Francesco; Del Maschio, Alessandro; Esposito, Antonio; Martelli, Fabio

    2015-01-01

    Magnetic resonance imaging (MRI) provides non-invasive, repetitive measures in the same individual, allowing the study of a physio-pathological event over time. In this study, we tested the performance of 7 Tesla multi-parametric MRI to monitor the dynamic changes of mouse skeletal muscle injury and regeneration upon acute ischemia induced by femoral artery dissection. T2-mapping (T2 relaxation time), diffusion-tensor imaging (Fractional Anisotropy) and perfusion by Dynamic Contrast-Enhanced MRI (K-trans) were measured and imaging results were correlated with histological morphometric analysis in both Gastrocnemius and Tibialis anterior muscles. We found that tissue damage positively correlated with T2-relaxation time, while myofiber regeneration and capillary density positively correlated with Fractional Anisotropy. Interestingly, K-trans positively correlated with capillary density. Accordingly, repeated MRI measurements between day 1 and day 28 after surgery in ischemic muscles showed that: 1) T2-relaxation time rapidly increased upon ischemia and then gradually declined, returning almost to basal level in the last phases of the regeneration process; 2) Fractional Anisotropy dropped upon ischemic damage induction and then recovered along with muscle regeneration and neoangiogenesis; 3) K-trans reached a minimum upon ischemia, then progressively recovered. Overall, Gastrocnemius and Tibialis anterior muscles displayed similar patterns of MRI parameters dynamic, with more marked responses and less variability in Tibialis anterior. We conclude that MRI provides quantitative information about both tissue damage after ischemia and the subsequent vascular and muscle regeneration, accounting for the differences between subjects and, within the same individual, between different muscles.

  3. Magnetic resonance image guided brachytherapy.

    PubMed

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

    2014-07-01

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

  4. Magnetic resonance imaging of radiation optic neuropathy

    SciTech Connect

    Zimmerman, C.F.; Schatz, N.J.; Glaser, J.S. )

    1990-10-15

    Three patients with delayed radiation optic neuropathy after radiation therapy for parasellar neoplasms underwent magnetic resonance imaging. The affected optic nerves and chiasms showed enlargement and focal gadopentetate dimeglumine enhancement. The magnetic resonance imaging technique effectively detected and defined anterior visual pathway changes of radionecrosis and excluded the clinical possibility of visual loss because of tumor recurrence.

  5. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    ERIC Educational Resources Information Center

    Pine, Daniel S.; Guyer, Amanda E.; Leibenluft, Ellen; Peterson, Bradley S.; Gerber, Andrew

    2008-01-01

    The use of functional magnetic resonance imaging in investigating pediatric anxiety disorders is studied. Functional magnetic resonance imaging can be utilized in demonstrating parallels between the neural architecture of difference in anxiety of humans and the neural architecture of attention-orienting behavior in nonhuman primates or rodents.…

  6. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    ERIC Educational Resources Information Center

    Pine, Daniel S.; Guyer, Amanda E.; Leibenluft, Ellen; Peterson, Bradley S.; Gerber, Andrew

    2008-01-01

    The use of functional magnetic resonance imaging in investigating pediatric anxiety disorders is studied. Functional magnetic resonance imaging can be utilized in demonstrating parallels between the neural architecture of difference in anxiety of humans and the neural architecture of attention-orienting behavior in nonhuman primates or rodents.…

  7. Prostate Cancer: The Role of Multiparametric Magnetic Resonance Imaging.

    PubMed

    Dias, João Lopes; Pina, João Magalhães; João, Raquel; Fialho, Joana; Carmo, Sandra; Leal, Cecília; Bilhim, Tiago; Marques, Rui Mateus; Pinheiro, Luís Campos

    2015-01-01

    Multiparametric magnetic resonance imaging has been increasingly used for detection, localization and staging of prostate cancer over the last years. It combines high-resolution T2 weighted-imaging and at least two functional techniques, which include dynamic contrast-enhanced magnetic resonance imaging, diffusion-weighted imaging, and magnetic resonance imaging spectroscopy. Although the combined use of a pelvic phased-array and an endorectal coil is considered the state-of-the-art for magnetic resonance imaging evaluation of prostate cancer, endorectal coil is only absolute mandatory for magnetic resonance imaging spectroscopy at 1.5 T. Sensitivity and specificity levels in cancer detection and localization have been improving with functional technique implementation, compared to T2 weighted-imaging alone. It has been particularly useful to evaluate patients with abnormal PSA and negative biopsy. Moreover, the information added by the functional techniques may correlate to cancer aggressiveness and therefore be useful to select patients for focal radiotherapy, prostate sparing surgery, focal ablative therapy and active surveillance. However, more studies are needed to compare the functional techniques and understand the advantages and disadvantages of each one. This article reviews the basic principles of prostatic mp-magnetic resonance imaging, emphasizing its role on detection, staging and active surveillance of prostate cancer.

  8. Magnetic resonance imaging of the nasopharynx

    SciTech Connect

    Dillon, W.P.; Mills, C.M.; Kjos, B.; DeGroot, J.; Brant-Zawadzki, M.

    1984-09-01

    Thirty subjects with normal nasopharyngeal anatomy and 12 patients with a variety of abnormalities were examined with computed tomography (CT) and magnetic resonance imaging (MR), using a prototype 0.35-T superconducting system. MR was superior to CT for display of both superficial and deep nasopharyngeal soft tissues in all 30 normal subjects and 10 of the 12 abnormal patients. MR was also superior to CT in distinguishing tumor from soft tissues and more sensitive to carotid sheath adenopathy. Bones, calcification, and subtle abnormalities at the base of the skull were shown better by CT. The specificity of MR and its ability to differentiate nodal metastases from reactive lymphadenopathy require further evaluation.

  9. Feasibility of 3.0 T diffusion-weighted nuclear magnetic resonance imaging in the evaluation of functional recovery of rats with complete spinal cord injury

    PubMed Central

    Zhang, Duo; Li, Xiao-hui; Zhai, Xu; He, Xi-jing

    2015-01-01

    Diffusion tensor imaging is a sensitive way to reflect axonal necrosis and degeneration, glial cell regeneration and demyelination following spinal cord injury, and to display microstructure changes in the spinal cord in vivo. Diffusion tensor imaging technology is a sensitive method to diagnose spinal cord injury; fiber tractography visualizes the white matter fibers, and directly displays the structural integrity and resultant damage of the fiber bundle. At present, diffusion tensor imaging is restricted to brain examinations, and is rarely applied in the evaluation of spinal cord injury. This study aimed to explore the fractional anisotropy and apparent diffusion coefficient of diffusion tensor magnetic resonance imaging and the feasibility of diffusion tensor tractography in the evaluation of complete spinal cord injury in rats. The results showed that the average combined scores were obviously decreased after spinal cord transection in rats, and then began to increase over time. The fractional anisotropy scores after spinal cord transection in rats were significantly lower than those in normal rats (P < 0.05); the apparent diffusion coefficient was significantly increased compared with the normal group (P < 0.05). Following spinal cord transection, fractional anisotropy scores were negatively correlated with apparent diffusion coefficient values (r = –0.856, P < 0.01), and positively correlated with the average combined scores (r = 0.943, P < 0.01), while apparent diffusion coefficient values had a negative correlation with the average combined scores (r = –0.949, P < 0.01). Experimental findings suggest that, as a non-invasive examination, diffusion tensor magnetic resonance imaging can provide qualitative and quantitative information about spinal cord injury. The fractional anisotropy score and apparent diffusion coefficient have a good correlation with the average combined scores, which reflect functional recovery after spinal cord injury. PMID:25878589

  10. Hypertrophic changes of the teres minor muscle in rotator cuff tears: quantitative evaluation by magnetic resonance imaging.

    PubMed

    Kikukawa, Kenshi; Ide, Junji; Kikuchi, Ken; Morita, Makoto; Mizuta, Hiroshi; Ogata, Hiroomi

    2014-12-01

    Few reports have assessed the teres minor (TM) muscle in rotator cuff tears. This study aimed to quantitatively analyze the morphologic changes of the TM muscle in patients with or without rotator cuff tears by magnetic resonance imaging (MRI). This retrospective study consisted of 279 subjects classified on the basis of interpretations of conventional MRI observations into 6 groups: no cuff tear; partial-thickness supraspinatus (SSP) tear; full-thickness SSP tear; SSP and subscapularis tears; SSP and infraspinatus (ISP) tears; and SSP, ISP, and subscapularis tears. With use of ImageJ software (National Institutes of Health, Bethesda, MD, USA) for oblique sagittal MRI, we measured the areas of ISP, TM, and anatomic external rotation (ISP + TM) muscles on the most lateral side in which the scapular spine was in contact with the scapular body. The occupational ratios of the TM muscle area to the anatomic external rotation muscle area were calculated. Ratios above the maximum of the 95% confidence intervals of the occupational ratio in the no-tear group were defined as hypertrophy of the TM muscle. Occupational ratios of the TM muscle in the no-tear group followed a normal distribution, and ratios >0.288 were defined as hypertrophic. Hypertrophic changes of the TM muscle were confirmed in rotator cuff tears involving the ISP tendon. A negative correlation was found between the occupational ratios of TM and ISP (P < .001). The TM muscle appeared hypertrophic in rotator cuff tears involving the ISP, and the progression of ISP muscle atrophy seemed to induce the development of this compensatory hypertrophy. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  11. Value of diffusion-weighted imaging when added to magnetic resonance enterographic evaluation of Crohn disease in children.

    PubMed

    Shenoy-Bhangle, Anuradha S; Nimkin, Katherine; Aranson, Thomas; Gee, Michael S

    2016-01-01

    MR enterography is increasingly utilized for noninvasive evaluation of disease activity in young patients with Crohn disease and has great impact on clinical management. Diffusion-weighted imaging (DWI) is a rapid MR imaging technique that measures molecular diffusion of water and is sensitive to the inflammatory process; however, its value to MR enterography has not been rigorously evaluated. To determine whether the addition of DWI to MR enterography is helpful in evaluating Crohn disease activity in young patients when compared to a histological reference. In this single-institution retrospective study, we searched an imaging database for the period January 2010 to December 2012 to identify patients age 19 years and younger who had MR enterography with diffusion-weighted imaging (DWI). We used an electronic medical record search to identify those who had MR enterography and colonoscopy performed within 28 days of each other. All MR enterography scans were performed on a 1.5-T or 3-T clinical MR scanner with phased-array torso coil configuration using standard pulse sequences as well as axial DWI with b values of 50, 400 and 800. Bowel segments were evaluated for disease activity based on standard MR enterography sequences; in addition, segmental apparent diffusion coefficient (ADC) values were calculated based on DWI. Histological reference for disease activity was based on assessment for mucosal inflammatory changes on endoscopic biopsy. MR enterography and DWI evaluation were performed in a blinded fashion with respect to histological results. We included imaging of 78 bowel segments from 27 patients (mean age 14.5 ± 3.02 years) with known Crohn disease in the study. The mean ADC for bowel segments with active disease was 1.56 ± 0.7 × 10(3) mm(2)/s compared with 2.58 ± 1.4 × 10(3) mm(2)/s for segments without active disease, a difference that was statistically significant (P < 0.01, Student's t-test). Using a threshold value of 2

  12. Evaluating the Role of Reduced Oxygen Saturation and Vascular Damage in Traumatic Brain Injury Using Magnetic Resonance Perfusion-Weighted Imaging and Susceptibility-Weighted Imaging and Mapping.

    PubMed

    Kou, Zhifeng; Ye, Yongquan; Haacke, Ewart Mark

    2015-10-01

    The cerebral vasculature, along with neurons and axons, is vulnerable to biomechanical insult during traumatic brain injury (TBI). Trauma-induced vascular injury is still an underinvestigated area in TBI research. Cerebral blood flow and metabolism could be important future treatment targets in neural critical care. Magnetic resonance imaging offers a number of key methods to probe vascular injury and its relationship with traumatic hemorrhage, perfusion deficits, venous blood oxygen saturation changes, and resultant tissue damage. They make it possible to image the hemodynamics of the brain, monitor regional damage, and potentially show changes induced in the brain's function not only acutely but also longitudinally following treatment. These methods have recently been used to show that even mild TBI (mTBI) subjects can have vascular abnormalities, and thus they provide a major step forward in better diagnosing mTBI patients.

  13. Evaluation of the susceptibility artifacts and tissue injury caused by implanted microchips in dogs on 1.5 T magnetic resonance imaging.

    PubMed

    Saito, Miyoko; Ono, Shin; Kayanuma, Hideki; Honnami, Muneki; Muto, Makoto; Une, Yumi

    2010-05-01

    Performing magnetic resonance imaging (MRI) in patients with a metallic implant raises concern over the potential complications, including susceptibility artifacts, implant migration, and heat injury. The purpose of this study was to investigate these complications in dogs with implanted microchips by evaluating MR images and the histopathological changes after 1.5 Tesla (T) MRI. Five dogs underwent microchip implantation in the cervicothoracic area. One month later, the area was imaged using 1.5T MRI in three dogs. The microchips were removed surgically together with the surrounding tissue in all dogs. There was significant signal loss and image distortion over a wide range around the area where the microchip was implanted. This change was consistent with susceptibility artifacts, which rendered the affected area including the spinal cord undiagnostic. The artifact was more extensive in T2*-weighted images (gradient-echo) and less extensive in proton density-weighted images (fast spin-echo with short echo time). Histopathologically, all microchips were well-encapsulated with granulation tissue, and there were no evidence of migration of microchips. Cell debris and a moderate number of degenerated cells with fibrin were seen in the inner layer of the granulation tissue in each dog that underwent MRI. These changes were very subtle and did not seem to be clinically significant. The results of this study suggest that, in 1.5T MRI, susceptibility artifacts produced by implanted microchips can be marked, although the dogs with implants appeared to be scanned safely.

  14. Cancer imaging: novel concepts in clinical magnetic resonance imaging.

    PubMed

    Kwee, T C; Takahara, T; Klomp, D W J; Luijten, P R

    2010-08-01

    Cancer is a major public health problem in the Western world. Imaging is of crucial importance in oncology, because it may reduce cancer-related morbidity and mortality. To improve tumour evaluation, there is a need for functional imaging modalities that go beyond gross assessment of anatomical abnormalities and allow visualization and quantification of biochemical processes in vivo. Magnetic resonance imaging (MRI) not only provides anatomical information, but also offers a wide range of functional sequences that may aid the evaluation of cancerous lesions. Furthermore, MRI provides the opportunity to guide and monitor anticancer therapies noninvasively. The aim of this review is to highlight some of the most promising developments of MRI in the functional assessment of cancer and the guidance and monitoring of (novel) anticancer therapies.

  15. COMPARISON OF NONCONTRAST COMPUTED TOMOGRAPHY AND HIGH-FIELD MAGNETIC RESONANCE IMAGING IN THE EVALUATION OF GREAT DANES WITH CERVICAL SPONDYLOMYELOPATHY

    PubMed Central

    Martin-Vaquero, Paula; Da Costa, Ronaldo C.; Drost, Wm Tod

    2014-01-01

    Computed tomography (CT) provides excellent bony detail, whereas magnetic resonance (MR) imaging is superior in evaluating the neural structures. The purpose of this prospective study was to assess interobserver and intermethod agreement in the evaluation of cervical vertebral column morphology and lesion severity in Great Danes with cervical spondylomyelopathy by use of noncontrast CT and high-field MR imaging. Fifteen client-owned affected Great Danes were enrolled. All dogs underwent noncontrast CT under sedation and MR imaging under general anesthesia of the cervical vertebral column. Three observers independently evaluated the images to determine the main site of spinal cord compression, direction and cause of the compression, articular process joint characteristics, and presence of foraminal stenosis. Overall intermethod agreement, intermethod agreement for each observer, overall interobserver agreement, and interobserver agreement between pairs of observers were calculated by use of kappa (κ) statistics. The highest overall intermethod agreements were obtained for the main site of compression and direction of compression with substantial agreements (κ = 0.65 and 0.62, respectively), whereas the lowest was obtained for right-sided foraminal stenosis (κ = 0.39, fair agreement). For both imaging techniques, the highest and lowest interobserver agreements were recorded for the main site of compression and degree of articular joint proliferation, respectively. While different observers frequently agree on the main site of compression using both imaging techniques, there is considerable variation between modalities and among observers when assessing articular process characteristics and foraminal stenosis. Caution should be exerted when comparing image interpretations from multiple observers. PMID:24547789

  16. Complete spontaneous regression of giant focal nodular hyperplasia of the liver: Magnetic resonance imaging evaluation with hepatobiliary contrast media.

    PubMed

    Mamone, Giuseppe; Caruso, Settimo; Cortis, Kelvin; Miraglia, Roberto

    2016-12-21

    Focal nodular hyperplasia (FNH) of the liver is a benign lesion occurring in 0.6%-3% of the general population that probably reflects a local hyperplastic response of hepatocytes to a vascular abnormality. Most lesions are diagnosed incidentally and the natural history of the disease remains largely unknown. It has been shown that most FNH remain stable, or even regress, over a long follow-up period. We present a patient with FNH of the liver who was followed up for 7 years. A 26-year-old woman with a 5-year history of oral contraceptive use was referred to our hospital in February 2005 for further examination of a liver tumour. The diagnosis of FNH was made using magnetic resonance (MR) imaging with hepatospecific contrast media; this technique allows a correct diagnosis, in particular distinguishing FNH from hepatic adenoma, avoiding an invasive procedure such as the lesion biopsy. After 7-year from the diagnosis, we observed the complete spontaneous regression of the lesion by enhanced MR scanning. In this patient, discontinuation of oral contraceptive use and two childbirths may have influenced the natural history of FNH. To our knowledge, in the English literature there is no report illustrating a complete regression of giant FNH but only studies of decreasing in size. The present case suggests that a young patient with giant FNH should be managed conservatively rather than by resection, because FNH has the potential for spontaneous regression.

  17. Imaging of the hip joint. Computed tomography versus magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Lang, P.; Genant, H. K.; Jergesen, H. E.; Murray, W. R.

    1992-01-01

    The authors reviewed the applications and limitations of computed tomography (CT) and magnetic resonance (MR) imaging in the assessment of the most common hip disorders. Magnetic resonance imaging is the most sensitive technique in detecting osteonecrosis of the femoral head. Magnetic resonance reflects the histologic changes associated with osteonecrosis very well, which may ultimately help to improve staging. Computed tomography can more accurately identify subchondral fractures than MR imaging and thus remains important for staging. In congenital dysplasia of the hip, the position of the nonossified femoral head in children less than six months of age can only be inferred by indirect signs on CT. Magnetic resonance imaging demonstrates the cartilaginous femoral head directly without ionizing radiation. Computed tomography remains the imaging modality of choice for evaluating fractures of the hip joint. In some patients, MR imaging demonstrates the fracture even when it is not apparent on radiography. In neoplasm, CT provides better assessment of calcification, ossification, and periosteal reaction than MR imaging. Magnetic resonance imaging, however, represents the most accurate imaging modality for evaluating intramedullary and soft-tissue extent of the tumor and identifying involvement of neurovascular bundles. Magnetic resonance imaging can also be used to monitor response to chemotherapy. In osteoarthrosis and rheumatoid arthritis of the hip, both CT and MR provide more detailed assessment of the severity of disease than conventional radiography because of their tomographic nature. Magnetic resonance imaging is unique in evaluating cartilage degeneration and loss, and in demonstrating soft-tissue alterations such as inflammatory synovial proliferation.

  18. Imaging of the hip joint. Computed tomography versus magnetic resonance imaging

    NASA Technical Reports Server (NTRS)

    Lang, P.; Genant, H. K.; Jergesen, H. E.; Murray, W. R.

    1992-01-01

    The authors reviewed the applications and limitations of computed tomography (CT) and magnetic resonance (MR) imaging in the assessment of the most common hip disorders. Magnetic resonance imaging is the most sensitive technique in detecting osteonecrosis of the femoral head. Magnetic resonance reflects the histologic changes associated with osteonecrosis very well, which may ultimately help to improve staging. Computed tomography can more accurately identify subchondral fractures than MR imaging and thus remains important for staging. In congenital dysplasia of the hip, the position of the nonossified femoral head in children less than six months of age can only be inferred by indirect signs on CT. Magnetic resonance imaging demonstrates the cartilaginous femoral head directly without ionizing radiation. Computed tomography remains the imaging modality of choice for evaluating fractures of the hip joint. In some patients, MR imaging demonstrates the fracture even when it is not apparent on radiography. In neoplasm, CT provides better assessment of calcification, ossification, and periosteal reaction than MR imaging. Magnetic resonance imaging, however, represents the most accurate imaging modality for evaluating intramedullary and soft-tissue extent of the tumor and identifying involvement of neurovascular bundles. Magnetic resonance imaging can also be used to monitor response to chemotherapy. In osteoarthrosis and rheumatoid arthritis of the hip, both CT and MR provide more detailed assessment of the severity of disease than conventional radiography because of their tomographic nature. Magnetic resonance imaging is unique in evaluating cartilage degeneration and loss, and in demonstrating soft-tissue alterations such as inflammatory synovial proliferation.

  19. Quantitative Evaluation of Growth Plates around the Knees of Adolescent Soccer Players by Diffusion-Weighted Magnetic Resonance Imaging

    PubMed Central

    Krajnc, Zmago; Rupreht, Mitja; Drobnič, Matej

    2015-01-01

    Purpose. To quantitatively evaluate growth plates around the knees in adolescent soccer players utilizing the diffusion-weighted MR imaging (DWI). Methods. The knees and adjacent growth plates of eleven 14-year-old male soccer players were evaluated by MRI before (end of season's summer break) and after two months of intense soccer training. MRI evaluation was conducted in coronal plane by PD-FSE and DWI. All images were screened for any major pathological changes. Later, central growth plate surface area (CGPSA) was measured and the apparent diffusion coefficient (ADC) values were calculated in two most central coronal slices divided into four regions: distal femur medial (DFM), distal femur lateral (DFL), proximal tibia medial (PTM), and proximal tibia lateral (PTL). Results. No gross pathology was diagnosed on MRI. CGPSA was not significantly reduced: DFM 278 versus 272, DFL 265 versus 261, PTM 193 versus 192, and PTL 214 versus 210. ADC decrease was statistically significant only for PTM: DFM 1.27 versus 1.22, DFL 1.37 versus 1.34, PTM 1.13 versus 1.03 (p = 0.003), and PTL 1.28 versus 1.22. Conclusions. DWI measurements indicate increased cellularity in growth plates around knees in footballers most prominent in PTM after intense training. No detectable differences on a standard PD-FSE sequence were observed. PMID:26693482

  20. Prenatal three-dimensional ultrasound and magnetic resonance imaging evaluation of a fetal oral tumor in preparation for the ex-utero intrapartum treatment (EXIT) procedure.

    PubMed

    Shih, J C; Hsu, W C; Chou, H C; Peng, S S; Chen, L K; Chang, Y L; Hsieh, F J

    2005-01-01

    Recent attempts at predelivery management of obstructed fetal airways have focused on the EXIT (ex-utero intrapartum treatment) procedure, which allows sufficient time to secure the fetal airway through preservation of uteroplacental gas exchange. We report a fetus with an exophytic oral tumor noted at 34 weeks of gestation. In this case, three-dimensional (3D) ultrasound allowed a complete and interactive evaluation of the tumor and related facial anatomy, and confirmed that access to the fetal airway was unlikely during delivery. Fetal magnetic resonance imaging (MRI) further demonstrated that the tumor originated in the nasopharynx and obstructed the upper airway. Both imaging results led to a final decision to offer an EXIT procedure for the neonate. At 36 weeks' gestation, a successful EXIT procedure was performed to reduce the risk of respiratory distress immediately after birth. This report highlights the value of 3D ultrasound and MRI as essential prerequisites for optimization of the triage process in selecting EXIT candidates.

  1. Magnetic resonance imaging of thyroid nodules

    SciTech Connect

    Kroop, S.A.; Margouleff, D.; Stein, H.L.; Zanzi, I.; Susin, M.; Goldman, M.A.

    1985-05-01

    The capacity of Magnetic Resonance (MR) imaging to characterize the nature of palpable thyroid nodules was prospectively evaluated in 9 patients. Seven nodules were nonfunctioning and 2 showed function on radio-iodine Nuclear Medicine (NM) scans. Each patient underwent high-resolution real time ultrasound (US) examination followed by MR imaging with a 0.6 Tesla superconducting whole body coil utilizing T/sub 1/ and T/sub 2/ weighted inversion recovery and spin-echo pulse sequences in coronal, transverse and sagittal planes. All NM, US and MR studies were evaluated independently by each of two physicians. Diagnoses were established by surgical pathology (n=7) or by radiologic and clinical correlation (n=2). There were 3 cases of solitary adenoma, 4 cases of adenomatous goiter, 1 case of papillary carcinoma and 1 case of epidermoid carcinoma. Lesions demonstrated variable signal intensity on T/sub 1/ weighted images. All lesions demonstrated nonspecific increased signal intensity on T/sub 2/ weighted images. One malignancy was correctly diagnosed by the identification of adjacent cervical lymph nodes of increased signal intensity and another by demonstration of tracheal invasion on MR images, both not visible by other imaging modalities. Regions of hemorrhage and cystic degeneration as well as additional non-palpable thyroid nodules could be detected on MR images. Vascular displacement, tracheal compression and deviation, and substernal thyroid extension were also well demonstrated. The findings suggest that qualitative assessment of MR signal intensity alone cannot reliably differentiate benign from malignant thyroid lesions, but that MR images can provide other useful information to aid in this differentiation.

  2. Image fusion for dynamic contrast enhanced magnetic resonance imaging

    PubMed Central

    Twellmann, Thorsten; Saalbach, Axel; Gerstung, Olaf; Leach, Martin O; Nattkemper, Tim W

    2004-01-01

    Background Multivariate imaging techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been shown to provide valuable information for medical diagnosis. Even though these techniques provide new information, integrating and evaluating the much wider range of information is a challenging task for the human observer. This task may be assisted with the use of image fusion algorithms. Methods In this paper, image fusion based on Kernel Principal Component Analysis (KPCA) is proposed for the first time. It is demonstrated that a priori knowledge about the data domain can be easily incorporated into the parametrisation of the KPCA, leading to task-oriented visualisations of the multivariate data. The results of the fusion process are compared with those of the well-known and established standard linear Principal Component Analysis (PCA) by means of temporal sequences of 3D MRI volumes from six patients who took part in a breast cancer screening study. Results The PCA and KPCA algorithms are able to integrate information from a sequence of MRI volumes into informative gray value or colour images. By incorporating a priori knowledge, the fusion process can be automated and optimised in order to visualise suspicious lesions with high contrast to normal tissue. Conclusion Our machine learning based image fusion approach maps the full signal space of a temporal DCE-MRI sequence to a single meaningful visualisation with good tissue/lesion contrast and thus supports the radiologist during manual image evaluation. PMID:15494072

  3. Evaluation of serial changes on computed tomography and magnetic resonance imaging after implantation of carmustine wafers in patients with malignant gliomas for differential diagnosis of tumor recurrence.

    PubMed

    Ohue, Shiro; Kohno, Shohei; Inoue, Akihiro; Yamashita, Daisuke; Suehiro, Satoshi; Seno, Toshimoto; Kumon, Yoshiaki; Kikuchi, Keiichi; Ohnishi, Takanori

    2016-01-01

    Carmustine wafers are approved for localized treatment of malignant glioma. In this study, overall changes in computed tomography (CT) and magnetic resonance (MR) images of malignant glioma patients treated with carmustine wafer implantation were evaluated. The subjects were 25 patients undergoing craniotomy for malignant glioma resection and carmustine wafer implantation. Changes in the appearance of wafers, the resection cavity, and the adjacent parenchyma on CT and MR imaging were evaluated retrospectively. On CT, the wafers changed from an initially high-dense to an iso-dense appearance. All MR studies showed a low-intense wafer within 2 days. The wafers changed to a high- or iso-intense appearance on fluid attenuated inversion recovery and T1-weighted imaging, whereas they changed to an iso- to low-intense appearance on T2-weighted imaging. Gas in the cavity increased gradually after surgery, achieved a peak at 1 week postoperatively, and then disappeared in 1-3 months. Increased volume of the resection cavity was observed in 48% of patients. Regarding changes in the adjacent parenchyma, obvious contrast enhancement at the wall of the resection cavity was seen in 91% of cases at 1 month, but this disappeared gradually. Edema around the resection cavity was increased in 7 patients (28%), of whom only two experienced symptoms due to edema. We conclude that these radiological changes after carmustine wafer implantation should be carefully followed up, because these changes can easily be mistaken for infectious disease or recurrent tumors.

  4. Evaluation of oxidative stress in the brain of a transgenic mouse model of Alzheimer disease by in vivo electron paramagnetic resonance imaging.

    PubMed

    Matsumura, Akihiro; Emoto, Miho C; Suzuki, Syuuichirou; Iwahara, Naotoshi; Hisahara, Shin; Kawamata, Jun; Suzuki, Hiromi; Yamauchi, Ayano; Sato-Akaba, Hideo; Fujii, Hirotada G; Shimohama, Shun

    2015-08-01

    Alzheimer disease (AD) is a neurodegenerative disease clinically characterized by progressive cognitive dysfunction. Deposition of amyloid-β (Aβ) peptides is the most important pathophysiological hallmark of AD. Oxidative stress induced by reactive oxygen species is prominent in AD, and several reports suggest the relationship between a change in redox status and AD pathology containing progressive Aβ deposition, the activation of glial cells, and mitochondrial dysfunction. Therefore, we performed immunohistochemical analysis using a transgenic mouse model of AD (APdE9) and evaluated the activity of superoxide dismutase in brain tissue homogenates of APdE9 mice in vitro. Together with those analyses, in vivo changes in redox status with age in both wild-type (WT) and APdE9 mouse brains were measured noninvasively by three-dimensional electron paramagnetic resonance (EPR) imaging using nitroxide (3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-yloxy) as a redox-sensitive probe. Both methods found similar changes in redox status with age, and in particular a significant change in redox status in the hippocampus was observed noninvasively by EPR imaging between APdE9 mice and age-matched WT mice from 9 to 18 months of age. EPR imaging clearly visualized the accelerated change in redox status of APdE9 mouse brain compared with WT. The evaluation of the redox status in the brain of AD model rodents by EPR imaging should be useful for diagnostic study of AD.

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

    MedlinePlus

    ... If You Have Questions en español Resonancia magnética: columna lumbar What It Is Magnetic resonance imaging (MRI) ... MORE ON THIS TOPIC Magnetic Resonance Imaging (MRI): Cervical Spine Lumbar Puncture (Spinal Tap) Magnetic Resonance Imaging ( ...

  6. Nuclear magnetic resonance imaging of the spine

    SciTech Connect

    Modic, M.T.; Weinstein, M.A.; Pavlicek, W.; Starnes, D.L.; Duchesneau, P.M.; Boumphrey, F.; Hardy, R.J. Jr.

    1984-01-01

    Forty subjects were examined to determine the accuracy and clinical usefulness of nuclear magnetic resonance (NMR) examination of the spine. The NMR images were compared with plain radiographs, high-resolution computed tomograms, and myelograms. The study included 15 patients with normal spinal cord anatomy and 25 patients whose pathological conditions included canal stenosis, herniated discs, metastatic tumors, primary cord tumor, trauma, Chiari malformations, syringomyelia, and developmental disorders. Saturation recovery images were best in differentiating between soft tissue and cerebrospinal fluid. NMR was excellent for the evaluation of the foramen magnum region and is presently the modality of choice for the diagnosis of syringomyelia and Chiari malformation. NMR was accurate in diagnosing spinal cord trauma and spinal canal block.

  7. Evaluating the role of Magnetic Resonance Imaging post Neoadjuvant Therapy for Breast Cancer in the NEONAB trial.

    PubMed

    Murphy, Caitlin; Mukaro, Violet; Tobler, Robert; Asher, Rebecca; Gibbs, Emma; West, Linda; Giuffre, Bruno; Baron-Hay, Sally; Khasraw, Mustafa

    2017-09-04

    Magnetic Resonance Imaging (MRI) accuracy after neoadjuvant systemic therapy (NST) for breast cancer varies according to hormone receptor (HR), human epidermal growth factor receptor type-2 (HER2) subtype and Ki67 proliferation index. Whether MRI accuracy varies by genomic signatures is unknown. We examined accuracy of MRI in the NEONAB trial (Clinicaltrials.gov #: NCT01830244). Patients with stage II-III breast cancer received sequential epirubicin, cyclophosphamide and nab-paclitaxel and trastuzumab if HER2+. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated to assess utility of preoperative MRI to predict pathological complete response (pCR). Bland-Altman plots were used to assess agreement between MRI and pathological assessment of residual disease. MRI correctly predicted pCR in 64.1% of the cohort. Sensitivity and specificity were 52% and 78%, PPV 73% and NPV 58%. MRI predicted pCR most accurately in HER2-positive patients; sensitivity 58%, specificity 100%, PPV 100% and NPV 38%. MRI had higher PPV and NPV in tumours with Ki67 ≥ 15% than tumours with Ki67 < 15%, 75% versus 50% and 57.5% versus 50% respectively. In this study, MRI underestimated residual tumour size by 1.65mm (limits of agreement: 43.07mm-39.77mm). MRI appears more accurate for predicting pCR in HER2+ disease than other subtypes and in cancers with Ki67 ≥15% compared to those with Ki67 <15%. Accuracy of MRI in our HR+, RS ≥ 25 cohort is comparable to previous reports of unselected HR+ disease. MRI post-NST should be interpreted in conjunction with HER2 status and Ki67 index of the primary. This article is protected by copyright. All rights reserved.

  8. Pretreatment Evaluation of Microcirculation by Dynamic Contrast-Enhanced Magnetic Resonance Imaging Predicts Survival in Primary Rectal Cancer Patients

    SciTech Connect

    DeVries, Alexander Friedrich; Piringer, Gudrun; Kremser, Christian; Judmaier, Werner; Saely, Christoph Hubert; Lukas, Peter; Öfner, Dietmar

    2014-12-01

    Purpose: To investigate the prognostic value of the perfusion index (PI), a microcirculatory parameter estimated from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), which integrates information on both flow and permeability, to predict overall survival and disease-free survival in patients with primary rectal cancer. Methods and Materials: A total of 83 patients with stage cT3 rectal cancer requiring neoadjuvant chemoradiation were investigated with DCE-MRI before start of therapy. Contrast-enhanced dynamic T{sub 1} mapping was obtained, and a simple data analysis strategy based on the calculation of the maximum slope of the tissue concentration–time curve divided by the maximum of the arterial input function was used as a measure of tumor microcirculation (PI), which integrates information on both flow and permeability. Results: In 39 patients (47.0%), T downstaging (ypT0-2) was observed. During a mean (±SD) follow-up period of 71 ± 29 months, 58 patients (69.9%) survived, and disease-free survival was achieved in 45 patients (54.2%). The mean PI (PImean) averaged over the group of nonresponders was significantly higher than for responders. Additionally, higher PImean in age- and gender-adjusted analyses was strongly predictive of therapy nonresponse. Most importantly, PImean strongly and significantly predicted disease-free survival (unadjusted hazard ratio [HR], 1.85 [ 95% confidence interval, 1.35-2.54; P<.001)]; HR adjusted for age and sex, 1.81 [1.30-2.51]; P<.001) as well as overall survival (unadjusted HR 1.42 [1.02-1.99], P=.040; HR adjusted for age and sex, 1.43 [1.03-1.98]; P=.034). Conclusions: This analysis identifies PImean as a novel biomarker that is predictive for therapy response, disease-free survival, and overall survival in patients with primary locally advanced rectal cancer.

  9. Multiparametric magnetic resonance imaging vs. standard care in men being evaluated for prostate cancer: a randomized study.

    PubMed

    Panebianco, Valeria; Barchetti, Flavio; Sciarra, Alessandro; Ciardi, Antonio; Indino, Elena Lucia; Papalia, Rocco; Gallucci, Michele; Tombolini, Vincenzo; Gentile, Vincenzo; Catalano, Carlo

    2015-01-01

    To assess whether the proportion of men with clinically significant prostate cancer (PCa) is higher among men randomized to multiparametric magnetic resonance imaging (mp-MRI)/biopsy vs. those randomized to transrectal ultrasound (TRUS)-guided biopsy. In total, 1,140 patients with symptoms highly suggestive of PCa were enrolled and divided in 2 groups of 570 patients to follow 2 different diagnostic algorithms. Group A underwent a TRUS-guided random biopsy. Group B underwent an mp-MRI and a TRUS-guided targeted+random biopsy. The accuracy of mp-MRI in the diagnosis of PCa was calculated using prostatectomy as the standard of reference. In group A, PCa was detected in 215 patients. The remaining 355 patients underwent an mp-MRI: the findings were positive in 208 and unremarkable in 147 patients. After the second random+targeted biopsy, PCa was detected in 186 of the 208 patients. In group B, 440 patients had positive findings on mp-MRI, and PCa was detected in 417 at first biopsy; 130 group B patients had unremarkable findings on both mp-MRI and biopsy. In the 130 group B patients with unremarkable findings on mp-MRI and biopsy, a PCa Gleason score of 6 or precancerous lesions were detected after saturation biopsy. mp-MRI showed an accuracy of 97% for the diagnosis of PCa. The proportion of men with clinically significant PCa is higher among those randomized to mp-MRI/biopsy vs. those randomized to TRUS-guided biopsy; moreover, mp-MRI is a very reliable tool to identify patients to schedule in active surveillance. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Dynamic contrast-enhanced magnetic resonance imaging: fundamentals and application to the evaluation of the peripheral perfusion

    PubMed Central

    Gordon, Yaron; Partovi, Sasan; Müller-Eschner, Matthias; Amarteifio, Erick; Bäuerle, Tobias; Weber, Marc-André; Kauczor, Hans-Ulrich

    2014-01-01

    Introduction The ability to ascertain information pertaining to peripheral perfusion through the analysis of tissues’ temporal reaction to the inflow of contrast agent (CA) was first recognized in the early 1990’s. Similar to other functional magnetic resonance imaging (MRI) techniques such as arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) MRI, dynamic contrast-enhanced MRI (DCE-MRI) was at first restricted to studies of the brain. Over the last two decades the spectrum of ailments, which have been studied with DCE-MRI, has been extensively broadened and has come to include pathologies of the heart notably infarction, stroke and further cerebral afflictions, a wide range of neoplasms with an emphasis on antiangiogenic treatment and early detection, as well as investigations of the peripheral vascular and musculoskeletal systems. Applications to peripheral perfusion DCE-MRI possesses an unparalleled capacity to quantitatively measure not only perfusion but also other diverse microvascular parameters such as vessel permeability and fluid volume fractions. More over the method is capable of not only assessing blood flowing through an organ, but in contrast to other noninvasive methods, the actual tissue perfusion. These unique features have recently found growing application in the study of the peripheral vascular system and most notably in the diagnosis and treatment of peripheral arterial occlusive disease (PAOD). Review outline The first part of this review will elucidate the fundamentals of data acquisition and interpretation of DCE-MRI, two areas that often remain baffling to the clinical and investigating physician because of their complexity. The second part will discuss developments and exciting perspectives of DCE-MRI regarding the assessment of perfusion in the extremities. Emerging clinical applications of DCE-MRI will be reviewed with a special focus on investigation of physiology and pathophysiology of the microvascular and

  11. Cavernous and inferior petrosal sinus sampling and dynamic magnetic resonance imaging in the preoperative evaluation of Cushing's disease.

    PubMed

    Potts, Matthew B; Shah, Jugal K; Molinaro, Annette M; Blevins, Lewis S; Tyrrell, J Blake; Kunwar, Sandeep; Dowd, Christopher F; Hetts, Steven W; Aghi, Manish K

    2014-02-01

    The surgical management of Cushing's disease is often complicated by difficulties detecting corticotropic adenomas. Various diagnostic modalities are used when conventional magnetic resonance imaging (MRI) is negative or inconclusive. We sought to analyze our use of two such modalities in the surgical management of Cushing's disease: (1) cavernous/inferior petrosal sinus sampling (central venous sampling, CVS) for adrenocorticotropic hormone and (2) dynamic MRI (dMRI). We conducted a single-center, retrospective review of all patients with Cushing's disease treated by a single neurosurgeon with endonasal transsphenoidal surgery. Accuracy of adenoma localization with CVS and dMRI was analyzed. Ninety-one consecutive patients were included. Pathology confirmed an adenoma in 66. Preoperative dMRI and CVS were performed in 40 and 37 patients, respectively, with 20 undergoing both studies. Surgical pathology was positive for adenoma in 31 dMRI patients, 25 CVS patients, and 13 who underwent both. Among patients with pathology confirming an adenoma, dMRI identified a lesion in 96.8% and correctly lateralized the lesion in 89.7%, while CVS correctly lateralized in 52.2-65.2% (depending on location of sampling). Among patients with both studies, dMRI and CVS correctly lateralized in 76.9 and 61.5-69.2%, respectively. Accuracy of CVS improved if only patients with symmetric venous drainage were considered. In this mixed population of Cushing's disease patients, dMRI was more accurate than CVS at localizing adenomas, supporting the use of advance MRI techniques in the work-up of Cushing's disease. CVS, however, remains an important tool in the workup of Cushing's syndrome.

  12. Cavity resonator coil for high field magnetic resonance imaging.

    PubMed

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

    2007-01-01

    A variant coil of the high frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. This coil design is similar to the popular birdcage coil but it has the advantage that it can be easily built following the physical principles of the cavity resonators [1]. The equivalent circuit approach was used to compute the resonant frequency of this coil design, and compared the results with those frequency values obtained with theory. A transceiver coil composed of 4 cavities with a rod length of 4.5 cm, and a resonant frequency of 170.29 MHz was built. Phantom images were then acquired to test its viability using standard imaging sequences. The theory facilitates its development for high frequency MRI applications of animal models.

  13. Stepped Impedance Resonators for High Field Magnetic Resonance Imaging

    PubMed Central

    Akgun, Can E.; DelaBarre, Lance; Yoo, Hyoungsuk; Sohn, Sung-Min; Snyder, Carl J.; Adriany, Gregor; Ugurbil, Kamil; Gopinath, Anand; Vaughan, J. Thomas

    2014-01-01

    Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high field magnetic resonance imaging (MRI). In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) multi-element transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections referred to as stepped impedance resonators (SIRs) is investigated. Single element simulation results in free space and in a phantom at 7 tesla (298 MHz) demonstrate the rationale and feasibility of the SIR design strategy. Simulation and image results at 7 tesla in a phantom and human head illustrate the improvements in transmit magnetic field, as well as, RF efficiency (transmit magnetic field versus SAR) when two different SIR designs are incorporated in 8-element volume coil configurations and compared to a volume coil consisting of microstrip elements. PMID:23508243

  14. Stepped impedance resonators for high-field magnetic resonance imaging.

    PubMed

    Akgun, Can E; DelaBarre, Lance; Yoo, Hyoungsuk; Sohn, Sung-Min; Snyder, Carl J; Adriany, Gregor; Ugurbil, Kamil; Gopinath, Anand; Vaughan, J Thomas

    2014-02-01

    Multi-element volume radio-frequency (RF) coils are an integral aspect of the growing field of high-field magnetic resonance imaging. In these systems, a popular volume coil of choice has become the transverse electromagnetic (TEM) transceiver coil consisting of microstrip resonators. In this paper, to further advance this design approach, a new microstrip resonator strategy in which the transmission line is segmented into alternating impedance sections, referred to as stepped impedance resonators (SIRs), is investigated. Single-element simulation results in free space and in a phantom at 7 T (298 MHz) demonstrate the rationale and feasibility of the SIR design strategy. Simulation and image results at 7 T in a phantom and human head illustrate the improvements in a transmit magnetic field, as well as RF efficiency (transmit magnetic field versus specific absorption rate) when two different SIR designs are incorporated in 8-element volume coil configurations and compared to a volume coil consisting of microstrip elements.

  15. Evaluation of biocompatible alginate- and deferoxamine-coated ternary composites for magnetic resonance imaging and gene delivery into glioblastoma cells

    PubMed Central

    Sham, Kathy W. Y.; Chak, Chun-Pong; Lai, Josie M. Y.; Lee, Siu-Fung

    2015-01-01

    Background This paper describes comparative studies in cytotoxicities, magnetic resonance imaging (MRI), and gene delivery into glioblastoma U87MG or U138MG cells with ternary composites that are consist of superparamagnetic iron oxide (SPIO) nanoparticles (NPs) (size: 8-10 nm) with different surface coatings, circular plasmid DNA (pDNA) (~4 kb) equipped with fluorescent/luminescent probe, and branched polyethylenimine (25 kDa, PDI 2.5). Methods Three types of SPIO-NPs were used, including: (I) naked iron oxide NPs with Fe-OH surface group (Bare-NP); (II) iron oxide NPs with a coating of alginate (Alg-NPs); and (III) iron oxide NPs with a coating of deferoxamine (Def-NPs). By tuning the polyethylenimine (PEI)/NP ratios and with a fixed DNA amount, different ternary composites were employed for NP/gene transfection into glioblastoma U87MG or U138MG cells, which were then characterized by Prussian blue staining, in vitro MRI, green fluorescence protein (GFP) fluorescence and luciferase assay. Results Among the composites prepared, 0.2 ng PEI/0.5 µg DNA/1.0 µg Bare-NP ternary composite possessed the best cellular uptake efficiency of NP to the cytoplasm, following the trend Bare-NP > Alg-NP > Def-NP. This observation was consistent to the MRI assessments with in vitro T2 relaxivity (r2) values of 46.0, 35.5, and 23.7 s−1·µM−1·Fe, respectively. For cellular uptake efficiency of the pDNA, all variations of PEI/NP ratios of the composites did not yield significant differences. However, cellular uptake efficiencies of pDNA in the ternary composites in U138MG cells were generally higher than that of U87MG cells by an order of magnitude. Exceptionally, the ternary composite 0.2 ng PEI/0.5 µg DNA/1.0 µg Bare-NP possessed a lowered luciferase activity RLU for gene expression in U138MG cells. A total of 0.2 ng PEI/0.5 µg DNA/0.1 µg Bare-NP would be uptaken to the cell nucleus with the highest luciferase activity. A working concentration range of PEI with at least

  16. Evaluation of biocompatible alginate- and deferoxamine-coated ternary composites for magnetic resonance imaging and gene delivery into glioblastoma cells.

    PubMed

    Leung, Ken Cham-Fai; Sham, Kathy W Y; Chak, Chun-Pong; Lai, Josie M Y; Lee, Siu-Fung; Wáng, Yì-Xiáng J; Cheng, Christopher H K

    2015-06-01

    This paper describes comparative studies in cytotoxicities, magnetic resonance imaging (MRI), and gene delivery into glioblastoma U87MG or U138MG cells with ternary composites that are consist of superparamagnetic iron oxide (SPIO) nanoparticles (NPs) (size: 8-10 nm) with different surface coatings, circular plasmid DNA (pDNA) (~4 kb) equipped with fluorescent/luminescent probe, and branched polyethylenimine (25 kDa, PDI 2.5). Three types of SPIO-NPs were used, including: (I) naked iron oxide NPs with Fe-OH surface group (Bare-NP); (II) iron oxide NPs with a coating of alginate (Alg-NPs); and (III) iron oxide NPs with a coating of deferoxamine (Def-NPs). By tuning the polyethylenimine (PEI)/NP ratios and with a fixed DNA amount, different ternary composites were employed for NP/gene transfection into glioblastoma U87MG or U138MG cells, which were then characterized by Prussian blue staining, in vitro MRI, green fluorescence protein (GFP) fluorescence and luciferase assay. Among the composites prepared, 0.2 ng PEI/0.5 µg DNA/1.0 µg Bare-NP ternary composite possessed the best cellular uptake efficiency of NP to the cytoplasm, following the trend Bare-NP > Alg-NP > Def-NP. This observation was consistent to the MRI assessments with in vitro T 2 relaxivity (r 2) values of 46.0, 35.5, and 23.7 s(-1)·µM(-1)·Fe, respectively. For cellular uptake efficiency of the pDNA, all variations of PEI/NP ratios of the composites did not yield significant differences. However, cellular uptake efficiencies of pDNA in the ternary composites in U138MG cells were generally higher than that of U87MG cells by an order of magnitude. Exceptionally, the ternary composite 0.2 ng PEI/0.5 µg DNA/1.0 µg Bare-NP possessed a lowered luciferase activity RLU for gene expression in U138MG cells. A total of 0.2 ng PEI/0.5 µg DNA/0.1 µg Bare-NP would be uptaken to the cell nucleus with the highest luciferase activity. A working concentration range of PEI with at least 15% higher cell

  17. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOEpatents

    Engelstad, B.L.; Raymond, K.N.; Huberty, J.P.; White, D.L.

    1991-04-23

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided. No Drawings

  18. Imaging agents for in vivo magnetic resonance and scintigraphic imaging

    DOEpatents

    Engelstad, Barry L.; Raymond, Kenneth N.; Huberty, John P.; White, David L.

    1991-01-01

    Methods are provided for in vivo magnetic resonance imaging and/or scintigraphic imaging of a subject using chelated transition metal and lanthanide metal complexes. Novel ligands for these complexes are provided.

  19. Magnetic resonance imaging of female urethral and periurethral disorders.

    PubMed

    Surabhi, Venkateswar Rao; Menias, Christine O; George, Verghese; Siegel, Cary Lynn; Prasad, Srinivasa R

    2013-11-01

    This article reviews the normal anatomy of the female urethra, magnetic resonance (MR) imaging techniques, and the role of MR imaging in the evaluation of diverse urethral and periurethral diseases. Salient MR imaging findings of common and uncommon cystic urethral lesions (urethral diverticulum, Skene cyst, and vaginal cysts), and masses (urethral carcinoma, leiomyoma, melanoma, fibroepithelial polyp, caruncle, and mucosal prolapse) are presented. The evolving role of dynamic MR in the evaluation of stress urinary incontinence is reviewed.

  20. Correlation Between Magnetic Resonance Imaging-Based Evaluation of Extramural Vascular Invasion and Prognostic Parameters of T3 Stage Rectal Cancer.

    PubMed

    Yu, Jing; Huang, Dong-Ya; Xu, Hui-Xin; Li, Yang; Xu, Qing

    2016-01-01

    The aim of this study was to analyze the correlation between magnetic resonance imaging-based extramural vascular invasion (EMVI) and the prognostic clinical and histological parameters of stage T3 rectal cancers. Eighty-six patients with T3 stage rectal cancer who received surgical resection without neoadjuvant therapy were included. Magnetic resonance imaging-based EMVI scores were determined. Correlations between the scores and pretreatment carcinoembryonic antigen levels, tumor differentiation grade, nodal stage, and vascular endothelial growth factor expression were analyzed using Spearman rank coefficient analysis. Magnetic resonance imaging-based EMVI scores were statistically different (P = 0.001) between histological nodal stages (N0 vs N1 vs N2). Correlations were found between magnetic resonance imaging-based EMVI scores and tumor histological grade (rs = 0.227, P = 0.035), histological nodal stage (rs = 0.524, P < 0.001), and vascular endothelial growth factor expression (rs = 0.422; P = 0.016). Magnetic resonance imaging-based EMVI score is correlated with prognostic parameters of T3 stage rectal cancers and has the potential to become an imaging biomarker of tumor aggressiveness. Magnetic resonance imaging-based EMVI may be useful in helping the multidisciplinary team to stratify T3 rectal cancer patients for neoadjuvant therapies.

  1. Magnetic resonance imaging of diabetic foot complications

    PubMed Central

    Low, Keynes TA; Peh, Wilfred CG

    2015-01-01

    This pictorial review aims to illustrate the various manifestations of the diabetic foot on magnetic resonance (MR) imaging. The utility of MR imaging and its imaging features in the diagnosis of pedal osteomyelitis are illustrated. There is often difficulty encountered in distinguishing osteomyelitis from neuroarthropathy, both clinically and on imaging. By providing an accurate diagnosis based on imaging, the radiologist plays a significant role in the management of patients with complications of diabetic foot. PMID:25640096

  2. Response evaluation of the neck in oropharyngeal cancer: Value of magnetic resonance imaging and influence of p16 in selecting patients for post-radiotherapy neck dissection.

    PubMed

    Lilja-Fischer, Jacob K; Jensen, Kenneth; Eskildsen, Helle W; Fink-Jensen, Vibeke; Nielsen, Viveque E

    2015-01-01

    Residual neck disease after radiotherapy in advanced oropharyngeal squamous cell carcinoma (OPSCC) is associated with increased mortality, and some patients may benefit from post-radiotherapy neck dissection (PRND). The aim of the present study was to assess the value of magnetic resonance imaging (MRI) and other clinical characteristics in selecting patients for PRND. Retrospective cohort study. Consecutive patients with N+ OPSCC were included. Medical records, pathology reports and imaging reports were reviewed. Pre- and post-therapeutic imaging was re-evaluated. A total of 100 consecutive patients from a three-year period were included. Neck response was evaluated with MRI two months after treatment. Sixty patients were suspicious for residual neck disease, and were offered surgery; seven of these patients had histologic evidence of carcinoma. Cumulative neck failure after three years was 14% (8.4-24%), and did not differ significantly among patients with positive compared to negative MRI (radiologist's initial description; p = 0.47, log-rank test). Applying neck failure as gold standard, sensitivity and specificity of MRI was 69% and 41%, respectively; positive and negative predictive value was 15% and 90%. Patients with p16 + disease had significantly larger lymph nodes after treatment, and imaging based on lymph node size resulted in many false positives. Analysis of receiver operating characteristic curves in 191 individual lymph nodes showed that a short axis ≥ 10 mm should be classified as suspicious. Furthermore, T-stage and p16-status were associated with increased risk of neck recurrence. Salvage was successful in four patients with early detected nodal recurrence. These results suggest that lymph node size, T-stage and p16 status could be used in selecting patients for PRND in OPSCC. Yet, early anatomical imaging may be inappropriate for evaluating neck response in patients with p16 + disease as enlarged lymph nodes often do not indicate residual

  3. Tools for cardiovascular magnetic resonance imaging

    PubMed Central

    Krishnamurthy, Ramkumar; Cheong, Benjamin

    2014-01-01

    In less than fifteen years, as a non-invasive imaging option, cardiovascular MR has grown from a being a mere curiosity to becoming a widely used clinical tool for evaluating cardiovascular disease. Cardiovascular magnetic resonance imaging (CMRI) is now routinely used to study myocardial structure, cardiac function, macro vascular blood flow, myocardial perfusion, and myocardial viability. For someone entering the field of cardiac MR, this rapid pace of development in the field of CMRI might make it difficult to identify a cohesive starting point. In this brief review, we have attempted to summarize the key cardiovascular imaging techniques that have found widespread clinical acceptance. In particular, we describe the essential cardiac and respiratory gating techniques that form the backbone of all cardiovascular imaging methods. It is followed by four sections that discuss: (I) the gradient echo techniques that are used to assess ventricular function; (II) black-blood turbo spin echo (SE) methods used for morphologic assessment of the heart; (III) phase-contrast based techniques for the assessment of blood flow; and (IV) CMR methods for the assessment of myocardial ischemia and viability. In each section, we briefly summarize technical considerations relevant to the clinical use of these techniques, followed by practical information for its clinical implementation. In each of those four areas, CMRI is considered either as the benchmark imaging modality against which the diagnostic performance of other imaging modalities are compared against, or provides a complementary capability to existing imaging techniques. We have deliberately avoided including cutting-edge CMR imaging techniques practiced at few academic centers, and restricted our discussion to methods that are widely used and are likely to be available in a clinical setting. Our hope is that this review would propel an interested reader toward more comprehensive reviews in the literature. PMID:24834409

  4. Magnetic Resonance Imaging of the Knee

    PubMed Central

    Hash, Thomas W.

    2013-01-01

    Context: Magnetic resonance imaging (MRI) affords high-resolution visualization of the soft tissue structures (menisci, ligaments, cartilage, etc) and bone marrow of the knee. Evidence Acquisition: Pertinent clinical and research articles in the orthopaedic and radiology literature over the past 30 years using PubMed. Results: Ligament tears can be accurately assessed with MRI, but distinguishing partial tears from ruptures of the anterior cruciate ligament (ACL) can be challenging. Determining the extent of a partial tear is often extremely difficult to accurately assess. The status of the posterolateral corner structures, menisci, and cartilage can be accurately evaluated, although limitations in the evaluation of certain structures exist. Patellofemoral joint, marrow, tibiofibular joint, and synovial pathology can supplement physical examination findings and provide definitive diagnosis. Conclusions: MRI provides an accurate noninvasive assessment of knee pathology. PMID:24381701

  5. Four-dimensional magnetic resonance imaging for the determination of tumour movement and its evaluation using a dynamic porcine lung phantom.

    PubMed

    Remmert, G; Biederer, J; Lohberger, F; Fabel, M; Hartmann, G H

    2007-09-21

    A method of four-dimensional (4D) magnetic resonance imaging (MRI) has been implemented and evaluated. It consists of retrospective sorting and slice stacking of two-dimensional (2D) images using an external signal for motion monitoring of the object to be imaged. The presented method aims to determine the tumour trajectories based on a signal that is appropriate for monitoring the movement of the target volume during radiotherapy such that the radiation delivery can be adapted to the movement. For evaluation of the 4D-MRI method, it has been applied to a dynamic lung phantom, which exhibits periodic respiratory movement of a porcine heart-lung explant with artificial pulmonary nodules. Anatomic changes of the lung phantom caused by respiratory motion have been quantified, revealing hysteresis. The results demonstrate the feasibility of the presented method of 4D-MRI. In particular, it enables the determination of trajectories of periodically moving objects with an uncertainty in the order of 1 mm.

  6. NOTE: Four-dimensional magnetic resonance imaging for the determination of tumour movement and its evaluation using a dynamic porcine lung phantom

    NASA Astrophysics Data System (ADS)

    Remmert, G.; Biederer, J.; Lohberger, F.; Fabel, M.; Hartmann, G. H.

    2007-09-01

    A method of four-dimensional (4D) magnetic resonance imaging (MRI) has been implemented and evaluated. It consists of retrospective sorting and slice stacking of two-dimensional (2D) images using an external signal for motion monitoring of the object to be imaged. The presented method aims to determine the tumour trajectories based on a signal that is appropriate for monitoring the movement of the target volume during radiotherapy such that the radiation delivery can be adapted to the movement. For evaluation of the 4D-MRI method, it has been applied to a dynamic lung phantom, which exhibits periodic respiratory movement of a porcine heart-lung explant with artificial pulmonary nodules. Anatomic changes of the lung phantom caused by respiratory motion have been quantified, revealing hysteresis. The results demonstrate the feasibility of the presented method of 4D-MRI. In particular, it enables the determination of trajectories of periodically moving objects with an uncertainty in the order of 1 mm.

  7. Evaluation of the Iron(iii) Complex of the 3,5 - Derivative of Catechol as AN Organ-Selective Magnetic Resonance Imaging Contrast Agent.

    NASA Astrophysics Data System (ADS)

    Sayed, M. Gary

    The iron (III) diethylsulfonamide derivative of catechol (Fe(III)-DESAC) is a new target selective magnetic resonance imaging contrast agent based on the second-sphere interaction mechanism. It is a highly stable tris-complex that was chemically characterized for potential use as a magnetopharmaceutical. The contrast agent was evaluated for gross toxicity and biodistribution in a Fisher 344 rat model. The agent showed no significant acute toxicity at low doses. At a higher dose, 0.15 mmol/kg, the contrast agent exhibited toxic effects in test animals. No signs of abnormal behavior or chronic toxicity was noted. Biodistribution studies revealed increased uptake by the liver parenchyma and the kidneys suggesting combined hepatobiliary and renal excretion. Its potential as a magnetopharmaceutical was evaluated using a GE Signa MRI scanner at 0.1 mmol/kg doses in phantom and an animal model. Relaxivity measurements resulted in R_1 and R_2 relaxivity values of 2.47 mM^{ -1} sec^{-1} and 3.16 mM^{-1} sec ^{-1}, respectively. T _1-weighted MR images showed 63% increase in the liver image values and 99% increase in the kidney values. This contrast enhancement was approximately 75% greater in the healthy parenchyma compared to the imbedded mammary adenocarcinoma.

  8. Role of Dynamic Magnetic Resonance Imaging in the Evaluation of Tumor Response to Preoperative Concurrent Radiochemotherapy for Large Breast Cancers: A Prospective Phase II Study

    SciTech Connect

    Bollet, Marc A. Thibault, Fabienne; Bouillon, Kim; Meunier, Martine; Sigal-Zafrani, Brigitte; Savignoni, Alexia; Dieras, Veronique; Nos, Claude; Salmon, Remy; Fourquet, Alain

    2007-09-01

    Purpose: To evaluate the accuracy of clinical examination and of three imaging modalities (ultrasound [US] scan, mammography, and magnetic resonance imaging [MRI]) to assess the tumor response of breast cancer to a preoperative regimen of concurrent radiochemotherapy for large breast cancers, using pathologic data as the reference. Methods and Materials: Sixty women were accrued. Treatment consisted of 4 cycles of (5-fluorouracil-vinorelbine) chemotherapy with, starting with the second cycle of chemotherapy, locoregional radiotherapy to the breast and the internal mammary and supraclavicular and infraclavicular lymph nodes. Breast surgery and axillary lymph node dissection were subsequently performed. Breast imaging assessments were performed both before chemotherapy and preoperatively. Results: The correlation coefficients between tumor dimension at imaging and pathology were statistically significant for US scan (r = 0.4; p = 0.006) and MRI (r = 0.4; p = 0.004) but not for clinical examination (r 0.2; p = 0.16) or mammography (r = -0.15; p = 0.31). Furthermore, the area under the receiver operating characteristic curve for MRI was 0.81, compared with 0.67 for US scan. At the optimal threshold score, MRI performed with 81% sensitivity and 75% specificity. Conclusion: Compared with clinical examination, US scan, or mammography, MRI substantially improved the prediction of pathologic tumor response to preoperative concurrent radiochemotherapy for large breast cancers.

  9. The Utility of Adding Magnetic Resonance Imaging to Computed Tomography Alone in the Evaluation of Cervical Spine Injury: A Propensity Matched Analysis.

    PubMed

    Schoenfeld, Andrew J; Tobert, Daniel G; Le, Hai V; Leonard, Dana A; Yau, Allan L; Rajan, Prashant; Cho, Charles H; Kang, James D; Bono, Christopher M; Harris, Mitchel B

    2017-06-19

    Adult patients who received CT alone or CT-MRI for the evaluation of cervical OBJECTIVE.: To evaluate the utility of CT-MRI in the diagnosis of cervical spine injury using propensity matched techniques. The optimal evaluation (computed tomography [CT] alone vs CT and magnetic resonance imaging [MRI]) for patients with suspected cervical spine injury in the setting of blunt trauma remains controversial. The primary outcome was the identification of a cervical spine injury, with decision for surgery and change in management considered secondarily. A propensity score was developed based on the likelihood of receiving evaluation with CT-MRI and this score was used to balance the cohorts and develop two groups of patients around whom there was a degree of clinical equipoise in terms of the imaging protocol. Logistic regression was used to evaluate for significant differences in injury detection in patients evaluated with CT alone as compared to those receiving CT-MRI. Between 2007-2014 8,060 patients were evaluated using CT and 693 with CT-MRI. Following propensity score matching, each cohort contained 668 patients. There were no significant differences between the two groups in baseline characteristics. The odds of identifying a cervical spine injury were significantly higher in the CT-MRI group, even after adjusting for prior injury recognition on CT (OR 2.6; 95% CI 1.7, 4.0; p < 0.001). However, only 53/668 patients (8%) in the CT-MRI group had injuries identified on MRI not previously recognized by CT. Only a minority of these patients (n = 5/668, 1%) necessitated surgical intervention. In this propensity matched cohort, the addition of MRI to CT alone identified missed injuries at a rate of 8%. Only a minority of these were serious enough to warrant surgery. This speaks against the standard addition of MRI to CT-alone protocols in cervical spine evaluation after trauma. 3.

  10. Detection of atherosclerosis via magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Alexander, Andrew L.; Pytlewski, Victor T.; Brown, Michael F.; Gmitro, Arthur F.

    1992-08-01

    Magnetic resonance imaging (MRI) of atherosclerotic lipids using a stimulated-echo diffusion- weighted (STED) sequence is demonstrated. The STED sequence exploits the large difference in diffusion between lipid (primarily cholesteryl ester) and water. The optimization of the STED sequence is discussed. The results of lipid imaging are corroborated with nuclear magnetic resonance (NMR) spectroscopy. This technique is non-invasive, and therefore, it is potentially useful in following the progression of the disease in animal models and in humans.

  11. Magnetic resonance image segmentation using semi-automated software for quantification of knee articular cartilage—initial evaluation of a technique for paired scans

    PubMed Central

    Brem, M. H.; Lang, P. K.; Neumann, G.; Schlechtweg, P. M.; Schneider, E.; Jackson, R.; Yu, J.; Eaton, C. B.; Hennig, F. F.; Yoshioka, H.; Pappas, G.; Duryea, J.

    2010-01-01

    Purpose Software-based image analysis is important for studies of cartilage changes in knee osteoarthritis (OA). This study describes an evaluation of a semi-automated cartilage segmentation software tool capable of quantifying paired images for potential use in longitudinal studies of knee OA. We describe the methodology behind the analysis and demonstrate its use by determination of test–retest analysis precision of duplicate knee magnetic resonance imaging (MRI) data sets. Methods Test–retest knee MR images of 12 subjects with a range of knee health were evaluated from the Osteoarthritis Initiative (OAI) pilot MR study. Each subject was removed from the magnet between the two scans. The 3D DESS (sagittal, 0.456 mm×0.365 mm, 0.7 mm slice thickness, TR 16.5 ms, TE 4.7 ms) images were obtained on a 3-T Siemens Trio MR system with a USA Instruments quadrature transmit–receive extremity coil. Segmentation of one 3D-image series was first performed and then the corresponding retest series was segmented by viewing both image series concurrently in two adjacent windows. After manual registration of the series, the first segmentation cartilage outline served as an initial estimate for the second segmentation. We evaluated morphometric measures of the bone and cartilage surface area (tAB and AC), cartilage volume (VC), and mean thickness (ThC.me) for medial/lateral tibia (MT/LT), total femur (F) and patella (P). Test–retest reproducibility was assessed using the root-mean square coefficient of variation (RMS CV%). Results For the paired analyses, RMS CV % ranged from 0.9% to 1.2% for VC, from 0.3% to 0.7% for AC, from 0.6% to 2.7% for tAB and 0.8% to 1.5% for ThC.me. Conclusion Paired image analysis improved the measurement precision of cartilage segmentation. Our results are in agreement with other publications supporting the use of paired analysis for longitudinal studies of knee OA. PMID:19252907

  12. Magnetic resonance image segmentation using semi-automated software for quantification of knee articular cartilage---initial evaluation of a technique for paired scans.

    PubMed

    Brem, M H; Lang, P K; Neumann, G; Schlechtweg, P M; Schneider, E; Jackson, R; Yu, J; Eaton, C B; Hennig, F F; Yoshioka, H; Pappas, G; Duryea, J

    2009-05-01

    Software-based image analysis is important for studies of cartilage changes in knee osteoarthritis (OA). This study describes an evaluation of a semi-automated cartilage segmentation software tool capable of quantifying paired images for potential use in longitudinal studies of knee OA. We describe the methodology behind the analysis and demonstrate its use by determination of test-retest analysis precision of duplicate knee magnetic resonance imaging (MRI) data sets. Test-retest knee MR images of 12 subjects with a range of knee health were evaluated from the Osteoarthritis Initiative (OAI) pilot MR study. Each subject was removed from the magnet between the two scans. The 3D DESS (sagittal, 0.456 mm x 0.365 mm, 0.7 mm slice thickness, TR 16.5 ms, TE 4.7 ms) images were obtained on a 3-T Siemens Trio MR system with a USA Instruments quadrature transmit-receive extremity coil. Segmentation of one 3D-image series was first performed and then the corresponding retest series was segmented by viewing both image series concurrently in two adjacent windows. After manual registration of the series, the first segmentation cartilage outline served as an initial estimate for the second segmentation. We evaluated morphometric measures of the bone and cartilage surface area (tAB and AC), cartilage volume (VC), and mean thickness (ThC.me) for medial/lateral tibia (MT/LT), total femur (F) and patella (P). Test-retest reproducibility was assessed using the root-mean square coefficient of variation (RMS CV%). For the paired analyses, RMS CV % ranged from 0.9% to 1.2% for VC, from 0.3% to 0.7% for AC, from 0.6% to 2.7% for tAB and 0.8% to 1.5% for ThC.me. Paired image analysis improved the measurement precision of cartilage segmentation. Our results are in agreement with other publications supporting the use of paired analysis for longitudinal studies of knee OA.

  13. Magnetic resonance imaging evaluation after implantation of a titanium cervical disc prosthesis: a comparison of 1.5 and 3 Tesla magnet strength.

    PubMed

    Sundseth, Jarle; Jacobsen, Eva A; Kolstad, Frode; Nygaard, Oystein P; Zwart, John A; Hol, Per K

    2013-10-01

    Cervical disc prostheses induce significant amount of artifact in magnetic resonance imaging which may complicate radiologic follow-up after surgery. The purpose of this study was to investigate as to what extent the artifact, induced by the frequently used Discover(®) cervical disc prosthesis, impedes interpretation of the MR images at operated and adjacent levels in 1.5 and 3 Tesla MR. Ten subsequent patients were investigated in both 1.5 and 3 Tesla MR with standard image sequences one year following anterior cervical discectomy with arthroplasty. Two neuroradiologists evaluated the images by consensus. Emphasis was made on signal changes in medulla at all levels and visualization of root canals at operated and adjacent levels. A "blur artifact ratio" was calculated and defined as the height of the artifact on T1 sagittal images related to the operated level. The artifacts induced in 1.5 and 3 Tesla MR were of entirely different character and evaluation of the spinal cord at operated level was impossible in both magnets. Artifacts also made the root canals difficult to assess at operated level and more pronounced in the 3 Tesla MR. At the adjacent levels however, the spinal cord and root canals were completely visualized in all patients. The "blur artifact" induced at operated level was also more pronounced in the 3 Tesla MR. The artifact induced by the Discover(®) titanium disc prosthesis in both 1.5 and 3 Tesla MR, makes interpretation of the spinal cord impossible and visualization of the root canals difficult at operated level. Adjusting the MR sequences to produce the least amount of artifact is important.

  14. Evaluating Prostate Cancer Using Fractional Tissue Composition of Radical Prostatectomy Specimens and Pre-Operative Diffusional Kurtosis Magnetic Resonance Imaging

    PubMed Central

    Lawrence, Edward M.; Warren, Anne Y.; Priest, Andrew N.; Barrett, Tristan; Goldman, Debra A.; Gill, Andrew B.

    2016-01-01

    Background Evaluating tissue heterogeneity using non-invasive imaging could potentially improve prostate cancer assessment and treatment. Methods 20 patients with intermediate/high-risk prostate cancer underwent diffusion kurtosis imaging, including calculation of apparent diffusion (Dapp) and kurtosis (Kapp), prior to radical prostatectomy. Whole-mount tissue composition was quantified into: cellularity, luminal space, and fibromuscular stroma. Peripheral zone tumors were subdivided according to Gleason score. Results Peripheral zone tumors had increased cellularity (p<0.0001), decreased fibromuscular stroma (p<0.05) and decreased luminal space (p<0.0001). Gleason score ≥4+3 tumors had significantly increased cellularity and decreased fibromuscular stroma compared to Gleason score ≤3+4 (p<0.05). In tumors, there was a significant positive correlation between median Kapp and cellularity (ρ = 0.50; p<0.05), and a negative correlation with fibromuscular stroma (ρ = -0.45; p<0.05). In normal tissue, median Dapp had a significant positive correlation with luminal space (ρ = 0.65; p<0.05) and a negative correlation with cellularity (ρ = -0.49; p<0.05). Median Kapp and Dapp varied significantly between tumor and normal tissue (p<0.0001), but only median Kapp was significantly different between Gleason score ≥4+3 and ≤3+4 (p<0.05). Conclusions Peripheral zone tumors have increased cellular heterogeneity which is reflected in mean Kapp, while normal prostate has a more homogeneous luminal space and cellularity better represented by Dapp. PMID:27467064

  15. Magnetic resonance imaging in glenohumeral instability

    PubMed Central

    Jana, Manisha; Gamanagatti, Shivanand

    2011-01-01

    The glenohumeral joint is the most commonly dislocated joint of the body and anterior instability is the most common type of shoulder instability. Magnetic resonance (MR) imaging, and more recently, MR arthrography, have become the essential investigation modalities of glenohumeral instability, especially for pre-procedure evaluation before arthroscopic surgery. Injuries associated with glenohumeral instability are variable, and can involve the bones, the labor-ligamentous components, or the rotator cuff. Anterior instability is associated with injuries of the anterior labrum and the anterior band of the inferior glenohumeral ligament, in the form of Bankart lesion and its variants; whereas posterior instability is associated with reverse Bankart and reverse Hill-Sachs lesion. Multidirectional instability often has no labral pathology on imaging but shows specific osseous changes such as increased chondrolabral retroversion. This article reviews the relevant anatomy in brief, the MR imaging technique and the arthrographic technique, and describes the MR findings in each type of instability as well as common imaging pitfalls. PMID:22007285

  16. Magnetic resonance imaging of navicular bursa adhesions.

    PubMed

    Holowinski, Maureen E; Solano, Mauricio; Maranda, Louise; García-López, José M

    2012-01-01

    Adhesions occur in the navicular bursa between the deep digital flexor tendon (DDFT) and other structures. Our objectives were to describe the appearance of navicular bursa adhesions on high-field magnetic resonance (MR) images, to compare these findings to findings at navicular bursoscopy, and to determine the prevalence of lesions in the remainder of the podotrochlear apparatus. Sixteen forelimbs from 14 horses that underwent MR imaging and navicular bursoscopy were evaluated. Adhesions were considered type 1 when characterized by a discontinuity in the navicular bursa fluid signal between two structures, type 2 when the navicular bursa fluid signal was disrupted and ill-defined tissue was present between two structures, and type 3 when the fluid signal was disrupted and well-defined tissue was present between two structures. Twenty-six adhesions were suspected on MR images and nineteen were visualized at surgery. The positive predictive value was 50% for type 1 adhesions, 67% for type 2 adhesions, and 100% for type 3 adhesions. Additional lesions were detected in the navicular bursa in 15 limbs, the DDFT in 13, the navicular bone in 15, the collateral sesamoidean ligaments in 9, and the distal sesamoidean impar ligament in 8. A discontinuity in the navicular bursa fluid signal with well-defined tissue between two structures detected on high-field MR images is diagnostic for a navicular bursa adhesion. Additional lesions in the podotrochlear apparatus are common in horses with navicular bursa adhesions. © 2012 Veterinary Radiology & Ultrasound.

  17. Apparatus for investigating resonance with application to magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Murphy, Sytil; Jones, Dyan L.; Gross, Josh; Zollman, Dean

    2015-11-01

    Resonance is typically studied in the context of either a pendulum or a mass on a spring. We have developed an apparatus that enables beginning students to investigate resonant behavior of changing magnetic fields, in addition to the properties of the magnetic field due to a wire and the superposition of magnetic fields. In this resonant system, a compass oscillates at a frequency determined by the compass's physical properties and an external magnetic field. While the analysis is mathematically similar to that of the pendulum, this apparatus has an advantage that the magnetic field is easily controlled, while it is difficult to control the strength of gravity. This apparatus has been incorporated into a teaching module on magnetic resonance imaging.

  18. Magnetic resonance imaging of the fetal brain.

    PubMed

    Tee, L Mf; Kan, E Yl; Cheung, J Cy; Leung, W C

    2016-06-01

    This review covers the recent literature on fetal brain magnetic resonance imaging, with emphasis on techniques, advances, common indications, and safety. We conducted a search of MEDLINE for articles published after 2010. The search terms used were "(fetal OR foetal OR fetus OR foetus) AND (MR OR MRI OR [magnetic resonance]) AND (brain OR cerebral)". Consensus statements from major authorities were also included. As a result, 44 relevant articles were included and formed the basis of this review. One major challenge is fetal motion that is largely overcome by ultra-fast sequences. Currently, single-shot fast spin-echo T2-weighted imaging remains the mainstay for motion resistance and anatomical delineation. Recently, a snap-shot inversion recovery sequence has enabled robust T1-weighted images to be obtained, which is previously a challenge for standard gradient-echo acquisitions. Fetal diffusion-weighted imaging, diffusion tensor imaging, and magnetic resonance spectroscopy are also being developed. With multiplanar capabilities, superior contrast resolution and field of view, magnetic resonance imaging does not have the limitations of sonography, and can provide additional important information. Common indications include ventriculomegaly, callosum and posterior fossa abnormalities, and twin complications. There are safety concerns about magnetic resonance-induced heating and acoustic damage but current literature showed no conclusive evidence of deleterious fetal effects. The American College of Radiology guideline states that pregnant patients can be accepted to undergo magnetic resonance imaging at any stage of pregnancy if risk-benefit ratio to patients warrants that the study be performed. Magnetic resonance imaging of the fetal brain is a safe and powerful adjunct to sonography in prenatal diagnosis. It can provide additional information that aids clinical management, prognostication, and counselling.

  19. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.

    ERIC Educational Resources Information Center

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-01-01

    Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

  20. Simple and Inexpensive Classroom Demonstrations of Nuclear Magnetic Resonance and Magnetic Resonance Imaging.

    ERIC Educational Resources Information Center

    Olson, Joel A.; Nordell, Karen J.; Chesnik, Marla A.; Landis, Clark R.; Ellis, Arthur B.; Rzchowski, M. S.; Condren, S. Michael; Lisensky, George C.

    2000-01-01

    Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

  1. Methodologies for semiquantitative evaluation of hip osteoarthritis by magnetic resonance imaging: approaches based on the whole organ and focused on active lesions.

    PubMed

    Jaremko, Jacob L; Lambert, Robert G W; Zubler, Veronika; Weber, Ulrich; Loeuille, Damien; Roemer, Frank W; Cibere, Jolanda; Pianta, Marcus; Gracey, David; Conaghan, Philip; Ostergaard, Mikkel; Maksymowych, Walter P

    2014-02-01

    As a wider variety of therapeutic options for osteoarthritis (OA) becomes available, there is an increasing need to objectively evaluate disease severity on magnetic resonance imaging (MRI). This is more technically challenging at the hip than at the knee, and as a result, few systematic scoring systems exist. The OMERACT (Outcome Measures in Rheumatology) filter of truth, discrimination, and feasibility can be used to validate image-based scoring systems. Our objective was (1) to review the imaging features relevant to the assessment of severity and progression of hip OA; and (2) to review currently used methods to grade these features in existing hip OA scoring systems. A systematic literature review was conducted. MEDLINE keyword search was performed for features of arthropathy (such as hip + bone marrow edema or lesion, synovitis, cyst, effusion, cartilage, etc.) and scoring system (hip + OA + MRI + score or grade), with a secondary manual search for additional references in the retrieved publications. Findings relevant to the severity of hip OA include imaging markers associated with inflammation (bone marrow lesion, synovitis, effusion), structural damage (cartilage loss, osteophytes, subchondral cysts, labral tears), and predisposing geometric factors (hip dysplasia, femoral-acetabular impingement). Two approaches to the semiquantitative assessment of hip OA are represented by Hip OA MRI Scoring System (HOAMS), a comprehensive whole organ assessment of nearly all findings, and the Hip Inflammation MRI Scoring System (HIMRISS), which selectively scores only active lesions (bone marrow lesion, synovitis/effusion). Validation is presently confined to limited assessment of reliability. Two methods for semiquantitative assessment of hip OA on MRI have been described and validation according to the OMERACT Filter is limited to evaluation of reliability.

  2. Basic principles of magnetic resonance imaging.

    PubMed

    McGowan, Joseph C

    2008-11-01

    Magnetic resonance (MR) imaging has become the dominant clinical imaging modality with widespread, primarily noninvasive, applicability throughout the body and across many disease processes. The flexibility of MR imaging enables the development of purpose-built optimized applications. Concurrent developments in digital image processing, microprocessor power, storage, and computer-aided design have spurred and enabled further growth in capability. Although MR imaging may be viewed as "mature" in some respects, the field is rich with new proposals and applications that hold great promise for future research health care uses. This article delineates the basic principles of MR imaging and illuminates specific applications.

  3. Magnetic resonance imaging of semicircular canals.

    PubMed Central

    Sbarbati, A; Leclercq, F; Zancanaro, C; Antonakis, K

    1992-01-01

    The present paper reports the results of the first investigation of the semicircular canals in a living, small animal by means of high spatial resolution magnetic resonance imaging. This procedure is noninvasive and allows identification of the endolymphatic and perilymphatic spaces yielding a morphology quite consistent with direct anatomical examination. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:1506290

  4. Magnetic Resonance Imaging in Biomedical Engineering

    NASA Astrophysics Data System (ADS)

    Kaśpar, Jan; Hána, Karel; Smrčka, Pavel; Brada, Jiří; Beneš, Jiří; Šunka, Pavel

    2007-11-01

    The basic principles of magnetic resonance imaging covering physical principles and basic imaging techniques will be presented as a strong tool in biomedical engineering. Several applications of MRI in biomedical research practiced at the MRI laboratory of the FBMI CTU including other laboratory instruments and activities are introduced.

  5. Brain Morphometry Using Anatomical Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Bansal, Ravi; Gerber, Andrew J.; Peterson, Bradley S.

    2008-01-01

    The efficacy of anatomical magnetic resonance imaging (MRI) in studying the morphological features of various regions of the brain is described, also providing the steps used in the processing and studying of the images. The ability to correlate these features with several clinical and psychological measures can help in using anatomical MRI to…

  6. Brain Morphometry Using Anatomical Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Bansal, Ravi; Gerber, Andrew J.; Peterson, Bradley S.

    2008-01-01

    The efficacy of anatomical magnetic resonance imaging (MRI) in studying the morphological features of various regions of the brain is described, also providing the steps used in the processing and studying of the images. The ability to correlate these features with several clinical and psychological measures can help in using anatomical MRI to…

  7. An evaluation of the left-brain vs. right-brain hypothesis with resting state functional connectivity magnetic resonance imaging.

    PubMed

    Nielsen, Jared A; Zielinski, Brandon A; Ferguson, Michael A; Lainhart, Janet E; Anderson, Jeffrey S

    2013-01-01

    Lateralized brain regions subserve functions such as language and visuospatial processing. It has been conjectured that individuals may be left-brain dominant or right-brain dominant based on personality and cognitive style, but neuroimaging data has not provided clear evidence whether such phenotypic differences in the strength of left-dominant or right-dominant networks exist. We evaluated whether strongly lateralized connections covaried within the same individuals. Data were analyzed from publicly available resting state scans for 1011 individuals between the ages of 7 and 29. For each subject, functional lateralization was measured for each pair of 7266 regions covering the gray matter at 5-mm resolution as a difference in correlation before and after inverting images across the midsagittal plane. The difference in gray matter density between homotopic coordinates was used as a regressor to reduce the effect of structural asymmetries on functional lateralization. Nine left- and 11 right-lateralized hubs were identified as peaks in the degree map from the graph of significantly lateralized connections. The left-lateralized hubs included regions from the default mode network (medial prefrontal cortex, posterior cingulate cortex, and temporoparietal junction) and language regions (e.g., Broca Area and Wernicke Area), whereas the right-lateralized hubs included regions from the attention control network (e.g., lateral intraparietal sulcus, anterior insula, area MT, and frontal eye fields). Left- and right-lateralized hubs formed two separable networks of mutually lateralized regions. Connections involving only left- or only right-lateralized hubs showed positive correlation across subjects, but only for connections sharing a node. Lateralization of brain connections appears to be a local rather than global property of brain networks, and our data are not consistent with a whole-brain phenotype of greater "left-brained" or greater "right-brained" network strength

  8. Incremental cancer detection using breast ultrasonography versus breast magnetic resonance imaging in the evaluation of newly diagnosed breast cancer patients

    PubMed Central

    Plaxco, Jeri S; Wei, Wei; Huo, Lei; Candelaria, Rosalind P; Kuerer, Henry M; Yang, Wei T

    2016-01-01

    Objective: To compare the incremental cancer detection rate (ICDR) using bilateral whole-breast ultrasonography (BWBUS) vs dynamic contrast-enhanced MRI in patients with primary breast cancer. Methods: A retrospective database search in a single institution identified 259 patients with breast cancer diagnosed from January 2011 to August 2014 who underwent mammography, BWBUS and MRI before surgery. Patient characteristics, tumour characteristics and lesions seen on each imaging modality were recorded. The sensitivity, specificity and accuracy for each modality were calculated. ICDRs according to index tumour histology and receptor status were also evaluated. The effect of additional cancer detection on surgical planning was obtained from the medical records. Results: A total of 266 additional lesions beyond 273 index malignancies were seen on at least 1 modality, of which 121 (45%) lesions were malignant and 145 (55%) lesions were benign. MRI was significantly more sensitive than BWBUS (p = 0.01), while BWBUS was significantly more accurate and specific than MRI (p < 0.0001). Compared with mammography, the ICDRs using BWBUS and MRI were significantly higher for oestrogen receptor-positive and triple-negative cancers, but not for human epidermal growth factor receptor 2-positive cancers. 22 additional malignant lesions in 18 patients were seen on MRI only. Surgical planning remained unchanged in 8 (44%) of those 18 patients. Conclusion: MRI was more sensitive than BWBUS, while BWBUS was more accurate and specific than MRI. MRI-detected additional malignant lesions did not change surgical planning in almost half of these patients. Advances in knowledge: BWBUS may be a cost-effective and practical tool in breast cancer staging. PMID:27384241

  9. An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging

    PubMed Central

    Nielsen, Jared A.; Zielinski, Brandon A.; Ferguson, Michael A.; Lainhart, Janet E.; Anderson, Jeffrey S.

    2013-01-01

    Lateralized brain regions subserve functions such as language and visuospatial processing. It has been conjectured that individuals may be left-brain dominant or right-brain dominant based on personality and cognitive style, but neuroimaging data has not provided clear evidence whether such phenotypic differences in the strength of left-dominant or right-dominant networks exist. We evaluated whether strongly lateralized connections covaried within the same individuals. Data were analyzed from publicly available resting state scans for 1011 individuals between the ages of 7 and 29. For each subject, functional lateralization was measured for each pair of 7266 regions covering the gray matter at 5-mm resolution as a difference in correlation before and after inverting images across the midsagittal plane. The difference in gray matter density between homotopic coordinates was used as a regressor to reduce the effect of structural asymmetries on functional lateralization. Nine left- and 11 right-lateralized hubs were identified as peaks in the degree map from the graph of significantly lateralized connections. The left-lateralized hubs included regions from the default mode network (medial prefrontal cortex, posterior cingulate cortex, and temporoparietal junction) and language regions (e.g., Broca Area and Wernicke Area), whereas the right-lateralized hubs included regions from the attention control network (e.g., lateral intraparietal sulcus, anterior insula, area MT, and frontal eye fields). Left- and right-lateralized hubs formed two separable networks of mutually lateralized regions. Connections involving only left- or only right-lateralized hubs showed positive correlation across subjects, but only for connections sharing a node. Lateralization of brain connections appears to be a local rather than global property of brain networks, and our data are not consistent with a whole-brain phenotype of greater “left-brained” or greater “right-brained” network

  10. EVALUATION OF MAGNETIC RESONANCE IMAGING GUIDELINES FOR DIFFERENTIATION BETWEEN THORACOLUMBAR INTERVERTEBRAL DISK EXTRUSIONS AND INTERVERTEBRAL DISK PROTRUSIONS IN DOGS.

    PubMed

    De Decker, Steven; Gomes, Sergio A; Packer, Rowena Ma; Kenny, Patrick J; Beltran, Elsa; Parzefall, Birgit; Fenn, Joe; Nair, Devi; Nye, George; Volk, Holger A

    2016-09-01

    Four MRI variables have recently been suggested to be independently associated with a diagnosis of thoracolumbar intervertebral disk extrusion or protrusion. Midline intervertebral disk herniation, and partial intervertebral disk degeneration were associated with intervertebral disk protrusion, while presence of a single intervertebral disk herniation and disk material dispersed beyond the boundaries of the intervertebral disk space were associated with intervertebral disk extrusion. The aim of this retrospective, cross-sectional study was to determine whether using these MRI variables improves differentiation between thoracolumbar intervertebral disk extrusions and protrusions. Eighty large breed dogs with surgically confirmed thoracolumbar intervertebral disk extrusions or protrusions were included. Randomized MRI studies were presented on two occasions to six blinded observers, which were divided into three experience categories. During the first assessment, observers made a presumptive diagnosis of thoracolumbar intervertebral disk extrusion or protrusion without guidelines. During the second assessment they were asked to make a presumptive diagnosis with the aid of guidelines. Agreement was evaluated by Kappa-statistics. Diagnostic accuracy significantly improved from 70.8 to 79.6% and interobserver agreement for making a diagnosis of intervertebral disk extrusion or intervertebral disk protrusion improved from fair (κ = 0.27) to moderate (κ = 0.41) after using the proposed guidelines. Diagnostic accuracy was significantly influenced by degree of observer experience. Intraobserver agreement for the assessed variables ranged from fair to excellent and interobserver agreement ranged from fair to moderate. The results of this study suggest that the proposed imaging guidelines can aid in differentiating thoracolumbar intervertebral disk extrusions from protrusions. © 2016 American College of Veterinary Radiology.

  11. Incremental cancer detection using breast ultrasonography versus breast magnetic resonance imaging in the evaluation of newly diagnosed breast cancer patients.

    PubMed

    He, Hongying; Plaxco, Jeri S; Wei, Wei; Huo, Lei; Candelaria, Rosalind P; Kuerer, Henry M; Yang, Wei T

    2016-09-01

    To compare the incremental cancer detection rate (ICDR) using bilateral whole-breast ultrasonography (BWBUS) vs dynamic contrast-enhanced MRI in patients with primary breast cancer. A retrospective database search in a single institution identified 259 patients with breast cancer diagnosed from January 2011 to August 2014 who underwent mammography, BWBUS and MRI before surgery. Patient characteristics, tumour characteristics and lesions seen on each imaging modality were recorded. The sensitivity, specificity and accuracy for each modality were calculated. ICDRs according to index tumour histology and receptor status were also evaluated. The effect of additional cancer detection on surgical planning was obtained from the medical records. A total of 266 additional lesions beyond 273 index malignancies were seen on at least 1 modality, of which 121 (45%) lesions were malignant and 145 (55%) lesions were benign. MRI was significantly more sensitive than BWBUS (p = 0.01), while BWBUS was significantly more accurate and specific than MRI (p < 0.0001). Compared with mammography, the ICDRs using BWBUS and MRI were significantly higher for oestrogen receptor-positive and triple-negative cancers, but not for human epidermal growth factor receptor 2-positive cancers. 22 additional malignant lesions in 18 patients were seen on MRI only. Surgical planning remained unchanged in 8 (44%) of those 18 patients. MRI was more sensitive than BWBUS, while BWBUS was more accurate and specific than MRI. MRI-detected additional malignant lesions did not change surgical planning in almost half of these patients. BWBUS may be a cost-effective and practical tool in breast cancer staging.

  12. Accuracy of computer-aided ultrasound as compared with magnetic resonance imaging in the evaluation of nonalcoholic fatty liver disease in obese and eutrophic adolescents*

    PubMed Central

    do Nascimento, José Hermes Ribas; Soder, Ricardo Bernardi; Epifanio, Matias; Baldisserotto, Matteo

    2015-01-01

    Objective To compare the accuracy of computer-aided ultrasound (US) and magnetic resonance imaging (MRI) by means of hepatorenal gradient analysis in the evaluation of nonalcoholic fatty liver disease (NAFLD) in adolescents. Materials and Methods This prospective, cross-sectional study evaluated 50 adolescents (aged 11–17 years), including 24 obese and 26 eutrophic individuals. All adolescents underwent computer-aided US, MRI, laboratory tests, and anthropometric evaluation. Sensitivity, specificity, positive and negative predictive values and accuracy were evaluated for both imaging methods, with subsequent generation of the receiver operating characteristic (ROC) curve and calculation of the area under the ROC curve to determine the most appropriate cutoff point for the hepatorenal gradient in order to predict the degree of steatosis, utilizing MRI results as the gold-standard. Results The obese group included 29.2% girls and 70.8% boys, and the eutrophic group, 69.2% girls and 30.8% boys. The prevalence of NAFLD corresponded to 19.2% for the eutrophic group and 83% for the obese group. The ROC curve generated for the hepatorenal gradient with a cutoff point of 13 presented 100% sensitivity and 100% specificity. As the same cutoff point was considered for the eutrophic group, false-positive results were observed in 9.5% of cases (90.5% specificity) and false-negative results in 0% (100% sensitivity). Conclusion Computer-aided US with hepatorenal gradient calculation is a simple and noninvasive technique for semiquantitative evaluation of hepatic echogenicity and could be useful in the follow-up of adolescents with NAFLD, population screening for this disease as well as for clinical studies. PMID:26379321

  13. Magnetic Resonance Image Wavelet Enhancer

    DTIC Science & Technology

    2001-10-25

    1Departamento de Ingenieria Electrica , UAM Iztapalapa, Mexico−DF, 09340, Mexico email:arog@xanum.uam.mx. Magnetic Resonance Centre, School of Physics...Number Task Number Work Unit Number Performing Organization Name(s) and Address(es) Departamento de Ingenieria Electrica , UAM Iztapalapa, Mexico-DF

  14. Mayer-Rokitansky-Kuster-Hauser syndrome diagnosed by magnetic resonance imaging. Role of imaging to identify and evaluate the uncommon variation in development of the female genital tract.

    PubMed

    Fiaschetti, Valeria; Taglieri, Amedeo; Gisone, Vito; Coco, Irene; Simonetti, Giovanni

    2012-04-01

    Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is a spectrum of Müllerian duct anomalies characterized by congenital aplasia of the uterus and of the upper part (2/3) of the vagina, in young women presenting otherwise with normal endocrine status. The ovaries and fallopian tubes are present. It is one of the most common causes of primary amenorrhea and affects at least 1 out of 4500 women. Its penetrance varies, as does the involvement of other organ systems and itcan be isolated (type I) or associated with other malformations (type II). The MRKH syndrome usually remains undetected until the patient presents with primary amenorrhea despite normal development of secondary sexual characteristics, so imaging evaluation can demonstrate in one setting, non invasively, the anomalies in development of genital tract. We report a case of MRKH syndrome in a 16-year-old woman who presented with primary amenorrhea, stressing the role and benefit of imaging in the differential diagnosis.

  15. Mayer-Rokitansky-Kuster-Hauser Syndrome diagnosed by Magnetic Resonance Imaging. Role of Imaging to identify and evaluate the uncommon variation in development of the female genital tract

    PubMed Central

    Fiaschetti, Valeria; Taglieri, Amedeo; Gisone, Vito; Coco, Irene; Simonetti, Giovanni

    2012-01-01

    Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is a spectrum of Müllerian duct anomalies characterized by congenital aplasia of the uterus and of the upper part (2/3) of the vagina, in young women presenting otherwise with normal endocrine status. The ovaries and fallopian tubes are present. It is one of the most common causes of primary amenorrhea and affects at least 1 out of 4500 women. Its penetrance varies, as does the involvement of other organ systems and itcan be isolated (type I) or associated with other malformations (type II). The MRKH syndrome usually remains undetected until the patient presents with primary amenorrhea despite normal development of secondary sexual characteristics, so imaging evaluation can demonstrate in one setting, non invasively, the anomalies in development of genital tract. We report a case of MRKH syndrome in a 16-year-old woman who presented with primary amenorrhea, stressing the role and benefit of imaging in the differential diagnosis. PMID:22690292

  16. Computationally efficient magnetic resonance imaging based surface contact modeling as a tool to evaluate joint injuries and outcomes of surgical interventions compared to finite element modeling.

    PubMed

    Johnson, Joshua E; Lee, Phil; McIff, Terence E; Toby, E Bruce; Fischer, Kenneth J

    2014-04-01

    Joint injuries and the resulting posttraumatic osteoarthritis (OA) are a significant problem. There is still a need for tools to evaluate joint injuries, their effect on joint mechanics, and the relationship between altered mechanics and OA. Better understanding of injuries and their relationship to OA may aid in the development or refinement of treatment methods. This may be partially achieved by monitoring changes in joint mechanics that are a direct consequence of injury. Techniques such as image-based finite element modeling can provide in vivo joint mechanics data but can also be laborious and computationally expensive. Alternate modeling techniques that can provide similar results in a computationally efficient manner are an attractive prospect. It is likely possible to estimate risk of OA due to injury from surface contact mechanics data alone. The objective of this study was to compare joint contact mechanics from image-based surface contact modeling (SCM) and finite element modeling (FEM) in normal, injured (scapholunate ligament tear), and surgically repaired radiocarpal joints. Since FEM is accepted as the gold standard to evaluate joint contact stresses, our assumption was that results obtained using this method would accurately represent the true value. Magnetic resonance images (MRI) of the normal, injured, and postoperative wrists of three subjects were acquired when relaxed and during functional grasp. Surface and volumetric models of the radiolunate and radioscaphoid articulations were constructed from the relaxed images for SCM and FEM analyses, respectively. Kinematic boundary conditions were acquired from image registration between the relaxed and grasp images. For the SCM technique, a linear contact relationship was used to estimate contact outcomes based on interactions of the rigid articular surfaces in contact. For FEM, a pressure-overclosure relationship was used to estimate outcomes based on deformable body contact interactions. The SCM

  17. Tutte polynomial in functional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    García-Castillón, Marlly V.

    2015-09-01

    Methods of graph theory are applied to the processing of functional magnetic resonance images. Specifically the Tutte polynomial is used to analyze such kind of images. Functional Magnetic Resonance Imaging provide us connectivity networks in the brain which are represented by graphs and the Tutte polynomial will be applied. The problem of computing the Tutte polynomial for a given graph is #P-hard even for planar graphs. For a practical application the maple packages "GraphTheory" and "SpecialGraphs" will be used. We will consider certain diagram which is depicting functional connectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The Tutte polynomial for the resulting neural networks will be computed and some numerical invariants for such network will be obtained. Our results show that the Tutte polynomial is a powerful tool to analyze and characterize the networks obtained from functional magnetic resonance imaging.

  18. Magnetic resonance imaging of the body

    SciTech Connect

    Higgins, C.B.; Hricak, H.

    1987-01-01

    This text provides reference to magnetic resonance imaging (MRI) of the body. Beginning with explanatory chapters on the physics, instrumentation, and interpretation of MRI, it proceeds to the normal anatomy of the neck, thorax, abdomen, and pelvis. Other chapters cover magnetic resonance imaging of blood flow, the larynx, the lymph nodes, and the spine, as well as MRI in obstetrics. The text features detailed coverage of magnetic resonance imaging of numerous disorders and disease states, including neck disease, thoracic disease; breast disease; congenital and acquired heart disease; vascular disease; diseases of the liver, pancreas, and spleen; diseases of the kidney, adrenals, and retroperitoneum; diseases of the male and female pelvis; and musculoskeletal diseases. Chapters on the biological and environmental hazards of MRI, the current clinical status of MRI in comparison to other imaging modalities, and economic considerations are also included.

  19. Magnetic resonance imaging of benign prostatic hyperplasia.

    PubMed

    Guneyli, Serkan; Ward, Emily; Thomas, Stephen; Yousuf, Ambereen Nehal; Trilisky, Igor; Peng, Yahui; Antic, Tatjana; Oto, Aytekin

    2016-01-01

    Benign prostatic hyperplasia (BPH) is a common condition in middle-aged and older men and negatively affects the quality of life. An ultrasound classification for BPH based on a previous pathologic classification was reported, and the types of BPH were classified according to different enlargement locations in the prostate. Afterwards, this classification was demonstrated using magnetic resonance imaging (MRI). The classification of BPH is important, as patients with different types of BPH can have different symptoms and treatment options. BPH types on MRI are as follows: type 0, an equal to or less than 25 cm3 prostate showing little or no zonal enlargements; type 1, bilateral transition zone (TZ) enlargement; type 2, retrourethral enlargement; type 3, bilateral TZ and retrourethral enlargement; type 4, pedunculated enlargement; type 5, pedunculated with bilateral TZ and/or retrourethral enlargement; type 6, subtrigonal or ectopic enlargement; type 7, other combinations of enlargements. We retrospectively evaluated MRI images of BPH patients who were histologically diagnosed and presented the different types of BPH on MRI. MRI, with its advantage of multiplanar imaging and superior soft tissue contrast resolution, can be used in BPH patients for differentiation of BPH from prostate cancer, estimation of zonal and entire prostatic volumes, determination of the stromal/glandular ratio, detection of the enlargement locations, and classification of BPH types which may be potentially helpful in choosing the optimal treatment.

  20. Magnetic resonance imaging of benign prostatic hyperplasia

    PubMed Central

    Guneyli, Serkan; Ward, Emily; Thomas, Stephen; Yousuf, Ambereen Nehal; Trilisky, Igor; Peng, Yahui; Antic, Tatjana; Oto, Aytekin

    2016-01-01

    Benign prostatic hyperplasia (BPH) is a common condition in middle-aged and older men and negatively affects the quality of life. An ultrasound classification for BPH based on a previous pathologic classification was reported, and the types of BPH were classified according to different enlargement locations in the prostate. Afterwards, this classification was demonstrated using magnetic resonance imaging (MRI). The classification of BPH is important, as patients with different types of BPH can have different symptoms and treatment options. BPH types on MRI are as follows: type 0, an equal to or less than 25 cm3 prostate showing little or no zonal enlargements; type 1, bilateral transition zone (TZ) enlargement; type 2, retrourethral enlargement; type 3, bilateral TZ and retrourethral enlargement; type 4, pedunculated enlargement; type 5, pedunculated with bilateral TZ and/or retrourethral enlargement; type 6, subtrigonal or ectopic enlargement; type 7, other combinations of enlargements. We retrospectively evaluated MRI images of BPH patients who were histologically diagnosed and presented the different types of BPH on MRI. MRI, with its advantage of multiplanar imaging and superior soft tissue contrast resolution, can be used in BPH patients for differentiation of BPH from prostate cancer, estimation of zonal and entire prostatic volumes, determination of the stromal/glandular ratio, detection of the enlargement locations, and classification of BPH types which may be potentially helpful in choosing the optimal treatment. PMID:27015442

  1. Intra voxel analysis in magnetic resonance imaging.

    PubMed

    Ambrosanio, Michele; Baselice, Fabio; Ferraioli, Giampaolo; Lenti, Flavia; Pascazio, Vito

    2017-04-01

    A technique for analyzing the composition of each voxel, in the magnetic resonance imaging (MRI) framework, is presented. By combining different acquisitions, a novel methodology, called intra voxel analysis (IVA), for the detection of multiple tissues and the estimation of their spin-spin relaxation times is proposed. The methodology exploits the sparse Bayesian learning (SBL) approach in order to solve a highly underdetermined problem imposing the solution sparsity. IVA, developed for spin echo imaging sequence, can be easily extended to any acquisition scheme. For validating the approach, simulated and real data sets are considered. Monte Carlo simulations have been implemented for evaluating the performances of IVA compared to methods existing in literature. Two clinical datasets acquired with a 3T scanner have been considered for validating the approach. With respect to other approaches presented in literature, IVA has proved to be more effective in the voxel composition analysis, in particular in the case of few acquired images. Results are interesting and very promising: IVA is expected to have a remarkable impact on the research community and on the diagnostic field. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Fetal magnetic resonance imaging in obstetric practice.

    PubMed

    Köşüş, Aydın; Köşüş, Nermin; Usluoğulları, Betül; Duran, Müzeyyen; Turhan, Nilgün Öztürk; Tekşam, Mehmet

    2011-01-01

    Ultrasonography (USG) is the primary imaging method for prenatal diagnosis of fetal abnormalities since its discovery. Although it is the primary method of fetal imaging, it cannot provide sufficient information about the fetus in some conditions such as maternal obesity, oligohydramnios and engagement of the fetal head. At this stage, magnetic resonance imaging (MRI) facilitates examination by providing more specific information. The need and importance of fetal MRI applications further increased by the intrauterine surgery which is currently gaining popularity. Some advantages of fetal MRI over USG are the good texture of contrast, a greater study area and visualization of the lesion and neighbourhood relations, independence of the operators. Also it is not affected by maternal obesity and severe oligohydramnios. However, MRI is inadequate in detecting fetal limb and cardiac abnormalities when compared to USG. MRI is not used routinely in pregnancy. It is used in situations where nonionizing imaging methods are inadequate or ionizing radiation is required in pregnant women. It is not recommended during the first trimester. Contrast agent (Godalinium) is not used during pregnancy. It is believed that MRI is not harmful to the fetus, although the biological risk of MRI application is not known. MRI technique is superior to USG in the detection of corpus callosum dysgenesis, third-trimester evaluation of posterior fossa malformations, bilateral renal agenesis, diaphragmatic hernia and assessment of lung maturation. Especially, it is the method of choice for evaluation of central nervous system (CNS) abnormalities. Fetal MRI has a complementary role with USG. It provides important information for prenatal diagnosis, increases diagnostic accuracy, and in turn affects the prenatal treatment, prenatal interventions and birth plan.

  3. Use of Magnetic Resonance in the Evaluation of Cranial Trauma.

    PubMed

    Altmeyer, Wilson; Steven, Andrew; Gutierrez, Juan

    2016-05-01

    MR imaging is an extremely useful tool in the evaluation of traumatic brain injury in the emergency department. Although CT still plays the dominant role in urgent patient triage, MR imaging's impact on traumatic brain injury imaging continues to expand. MR imaging has shown superiority to CT for certain traumatic processes, such as diffuse axonal injury, cerebral contusion, and infarction. Magnetic resonance angiography and magnetic resonance venography allow emergent vascular imaging for patients that should avoid ionizing radiation or intravenous contrast. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Evaluating local lymph node metastasis with magnetic resonance imaging, endoluminal ultrasound and computed tomography in rectal cancer: a meta-analysis.

    PubMed

    Li, X-T; Sun, Y-S; Tang, L; Cao, K; Zhang, X-Y

    2015-06-01

    Magnetic resonance imaging (MRI), endorectal ultrasound (EUS) and computed tomography (CT) are commonly used to evaluate lymph node (LN) metastasis for rectal cancer, but there is no agreement on which form of imaging is most accurate. The study aimed to review systematically the diagnostic performance of the three imaging modalities. The PubMed, Cochrane Library and EMBASE databases were systematically searched for English and Chinese language studies evaluating the diagnostic accuracy of MRI, EUS and/or CT for evaluating LN metastasis. Papers published before 31 December 2013 were included in the search. Subject-level data were included. Diagnostic odds ratios were calculated for each modality and summary receiver operating characteristic curves were constructed using hierarchical regression models. The performance of the three modalities was compared. The analysis included data from 123 studies evaluating LN metastasis. The sensitivity and specificity in patients having no chemoradiotherapy were 0.77 and 0.76 for MRI, 0.57 and 0.80 for EUS and 0.79 and 0.76 for CT. The three modalities showed similar accuracy (P = 0.39). MRI showed higher accuracy than EUS for patients who received neoadjuvant therapy (P = 0.04). MRI at a field strength > 1.5 T yielded better performance than EUS (P = 0.03) and similar performance to CT (P = 0.17). High resolution MRI showed similar diagnostic accuracy to EUS (P = 0.18) and CT (P = 0.16). MRI, EUS and CT show similar accuracy but none could provide reliable evaluation for LN metastasis. MRI rather than EUS is recommended for LN evaluation after neoadjuvant therapy. MRI at a field strength of 3.0 T is the recommended method for MRI examination. But high resolution MRI does not improve the diagnostic performance in evaluating LN metastasis. Colorectal Disease © 2015 The Association of Coloproctology of Great Britain and Ireland.

  5. Magnetic resonance image enhancement using stochastic resonance in Fourier domain.

    PubMed

    Rallabandi, V P Subramanyam; Roy, Prasun Kumar

    2010-11-01

    In general, low-field MRI scanners such as the 0.5- and 1-T ones produce images that are poor in quality. The motivation of this study was to lessen the noise and enhance the signal such that the image quality is improved. Here, we propose a new approach using stochastic resonance (SR)-based transform in Fourier space for the enhancement of magnetic resonance images of brain lesions, by utilizing an optimized level of Gaussian fluctuation that maximizes signal-to-noise ratio (SNR). We acquired the T1-weighted MR image of the brain in DICOM format. We processed the original MR image using the proposed SR procedure. We then tested our approach on about 60 patients of different age groups with different lesions, such as arteriovenous malformation, benign lesion and malignant tumor, and illustrated the image enhancement by using just-noticeable difference visually as well as by utilizing the relative enhancement factor quantitatively. Our method can restore the original image from noisy image and optimally enhance the edges or boundaries of the tissues, clarify indistinct structural brain lesions without producing ringing artifacts, as well as delineate the edematous area, active tumor zone, lesion heterogeneity or morphology, and vascular abnormality. The proposed technique improves the enhancement factor better than the conventional techniques like the Wiener- and wavelet-based procedures. The proposed method can readily enhance the image fusing a unique constructive interaction of noise and signal, and enables improved diagnosis over conventional methods. The approach well illustrates the novel potential of using a small amount of Gaussian noise to improve the image quality. Copyright © 2010 Elsevier Inc. All rights reserved.

  6. Magnetic resonance imaging measurement of iron overload

    PubMed Central

    Wood, John C.

    2010-01-01

    Purpose of review To highlight recent advances in magnetic resonance imaging estimation of somatic iron overload. This review will discuss the need and principles of magnetic resonance imaging-based iron measurements, the validation of liver and cardiac iron measurements, and the key institutional requirements for implementation. Recent findings Magnetic resonance imaging assessment of liver and cardiac iron has achieved critical levels of availability, utility, and validity to serve as the primary endpoint of clinical trials. Calibration curves for the magnetic resonance imaging parameters R2 and R2* (or their reciprocals, T2 and T2*) have been developed for the liver and the heart. Interscanner variability for these techniques has proven to be on the order of 5–7%. Summary Magnetic resonance imaging assessment of tissue iron is becoming increasingly important in the management of transfusional iron load because it is noninvasive, relatively widely available and offers a window into presymptomatic organ dysfunction. The techniques are highly reproducible within and across machines and have been chemically validated in the liver and the heart. These techniques will become the standard of care as industry begins to support the acquisition and postprocessing software. PMID:17414205

  7. Magnetic resonance imaging of skeletal muscle.

    PubMed

    Koltzenburg, Martin; Yousry, Tarek

    2007-10-01

    Clinical investigations of neuromuscular diseases routinely involve genetic, neurophysiological, biochemical and histopathological methods. More recently, various magnetic resonance imaging techniques have become available and extended the differential diagnostic possibilities. Using magnetic resonance imaging it is now possible to quantify muscle volume in selected body regions and measure wasting and exercise-induced muscle hypertrophy. Evidence is forthcoming that many hereditary myopathies are characterized by distinct patterns of muscle degeneration and this helps in selecting other relevant genetic and biochemical investigations. With diffusion-weighted tensor imaging it is possible to identify the microstructure of normal and diseased muscles. Arterial spin labelling is an emerging non-invasive tool to assess blood-flow changes in individual muscles. Magnetic resonance spectroscopy now provides an exciting opportunity to visualize metabolic changes and the pathophysiologically relevant cellular perturbations in muscle channelopathies affecting the muscle-specific sodium-channel isoform Na(v)1.4. Magnetic resonance imaging supplements investigations for the differential diagnosis of neuromuscular diseases. An advantage over routine neurophysiological or histopathological methods is that they are operator-independent, non-invasive and painless. Magnetic resonance imaging also has the advantage of providing a lasting detailed topographical picture of regional variations and allows robust measurements of muscle volume and various functional parameters.

  8. Correlation of Magnetic Resonance Imaging Tumor Volume with Histopathology

    PubMed Central

    Turkbey, Baris; Mani, Haresh; Aras, Omer; Rastinehad, Ardeshir R.; Shah, Vijay; Bernardo, Marcelino; Pohida, Thomas; Daar, Dagane; Benjamin, Compton; McKinney, Yolanda L.; Linehan, W. Marston; Wood, Bradford J.; Merino, Maria J.; Choyke, Peter L.; Pinto, Peter A.

    2017-01-01

    Purpose The biology of prostate cancer may be influenced by the index lesion. The definition of index lesion volume is important for appropriate decision making, especially for image guided focal treatment. We determined the accuracy of magnetic resonance imaging for determining index tumor volume compared with volumes derived from histopathology. Materials and Methods We evaluated 135 patients (mean age 59.3 years) with a mean prostate specific antigen of 6.74 ng/dl who underwent multiparametric 3T endorectal coil magnetic resonance imaging of the prostate and subsequent radical prostatectomy. Index tumor volume was determined prospectively and independently by magnetic resonance imaging and histopathology. The ellipsoid formula was applied to determine histopathology tumor volume, whereas manual tumor segmentation was used to determine magnetic resonance tumor volume. Histopathology tumor volume was correlated with age and prostate specific antigen whereas magnetic resonance tumor volume involved Pearson correlation and linear regression methods. In addition, the predictive power of magnetic resonance tumor volume, prostate specific antigen and age for estimating histopathology tumor volume (greater than 0.5 cm3) was assessed by ROC analysis. The same analysis was also conducted for the 1.15 shrinkage factor corrected histopathology data set. Results There was a positive correlation between histopathology tumor volume and magnetic resonance tumor volume (Pearson coefficient 0.633, p <0.0001), but a weak correlation between prostate specific antigen and histopathology tumor volume (Pearson coefficient 0.237, p=0.003). On linear regression analysis histopathology tumor volume and magnetic resonance tumor volume were correlated (r2=0.401, p <0.00001). On ROC analysis AUC values for magnetic resonance tumor volume, prostate specific antigen and age in estimating tumors larger than 0.5 cm3 at histopathology were 0.949 (p <0.0000001), 0.685 (p=0.001) and 0.627 (p=0

  9. Correlation of magnetic resonance imaging tumor volume with histopathology.

    PubMed

    Turkbey, Baris; Mani, Haresh; Aras, Omer; Rastinehad, Ardeshir R; Shah, Vijay; Bernardo, Marcelino; Pohida, Thomas; Daar, Dagane; Benjamin, Compton; McKinney, Yolanda L; Linehan, W Marston; Wood, Bradford J; Merino, Maria J; Choyke, Peter L; Pinto, Peter A

    2012-10-01

    The biology of prostate cancer may be influenced by the index lesion. The definition of index lesion volume is important for appropriate decision making, especially for image guided focal treatment. We determined the accuracy of magnetic resonance imaging for determining index tumor volume compared with volumes derived from histopathology. We evaluated 135 patients (mean age 59.3 years) with a mean prostate specific antigen of 6.74 ng/dl who underwent multiparametric 3T endorectal coil magnetic resonance imaging of the prostate and subsequent radical prostatectomy. Index tumor volume was determined prospectively and independently by magnetic resonance imaging and histopathology. The ellipsoid formula was applied to determine histopathology tumor volume, whereas manual tumor segmentation was used to determine magnetic resonance tumor volume. Histopathology tumor volume was correlated with age and prostate specific antigen whereas magnetic resonance tumor volume involved Pearson correlation and linear regression methods. In addition, the predictive power of magnetic resonance tumor volume, prostate specific antigen and age for estimating histopathology tumor volume (greater than 0.5 cm(3)) was assessed by ROC analysis. The same analysis was also conducted for the 1.15 shrinkage factor corrected histopathology data set. There was a positive correlation between histopathology tumor volume and magnetic resonance tumor volume (Pearson coefficient 0.633, p <0.0001), but a weak correlation between prostate specific antigen and histopathology tumor volume (Pearson coefficient 0.237, p = 0.003). On linear regression analysis histopathology tumor volume and magnetic resonance tumor volume were correlated (r(2) = 0.401, p <0.00001). On ROC analysis AUC values for magnetic resonance tumor volume, prostate specific antigen and age in estimating tumors larger than 0.5 cm(3) at histopathology were 0.949 (p <0.0000001), 0.685 (p = 0.001) and 0.627 (p = 0.02), respectively. Similar

  10. Magnetic Resonance Imaging of the Retina

    PubMed Central

    Duong, Timothy Q.; Muir, Eric R.

    2010-01-01

    This paper reviews recent developments in high-resolution magnetic resonance imaging (MRI) and its application to image anatomy, physiology, and function in the retina of animals. It describes technical issues and solutions in performing retinal MRI, anatomical MRI, blood oxygenation level-dependent functional MRI (fMRI), and blood-flow MRI both of normal retinas and of retinal degeneration. MRI offers unique advantages over existing retinal imaging techniques, including the ability to image multiple layers without depth limitation and to provide multiple clinically relevant data in a single setting. Retinal MRI has the potential to complement existing retinal imaging techniques. PMID:19763752

  11. Does Magnetic Resonance Imaging Improve the Predictive Performance of a Validated Clinical Prediction Rule Developed to Evaluate Surgical Outcome in Patients With Degenerative Cervical Myelopathy?

    PubMed

    Nouri, Aria; Tetreault, Lindsay; Côté, Pierre; Zamorano, Juan J; Dalzell, Kristian; Fehlings, Michael G

    2015-07-15

    Ambispective study. To determine whether MRI parameters improve the predictive performance of a validated clinical prediction rule used to assess functional outcomes in surgical patients with DCM. Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord dysfunction in the elderly worldwide. A clinical prediction rule was developed to discriminate between patients with mild myelopathy postoperatively (mJOA ≥ 16) and those with substantial residual neurological impairment (mJOA < 16). Recently, a separate magnetic resonance imaging (MRI)-based prediction model was created. However, a model exploring the combined predictive value of imaging and clinical variables does not exist. One hundred and fourteen patients with MRIs were examined from a cohort of 278 patients enrolled in the AOSpine CSM-North America Study. Ninety-nine patients had complete preoperative imaging and postoperative outcome data. MRIs were evaluated for the presence/absence of signal change on T2- and T1-weighted images. Quantitative analysis of the T2 signal change was conducted and maximum canal compromise and cord compression were calculated. The added predictive performance of each MRI parameter to the clinical model was evaluated using receiver operator characteristic curves. The model developed on our subsample yielded an area under the receiver operator curve (AUC) of 0.811 (95% CI: 0.726-0.896). The addition of imaging variables did not significantly improve the predictive performance. Small improvements in prediction were obtained when sagittal extent of T2 hyperintensity (AUC: 0.826, 95% CI: 0.743-0.908, 1.35% increase) or Wang ratio (AUC: 0.823, 95% CI: 0.739-0.907, 1.21%) was added. Anatomic characteristics, such as maximum canal compromise and maximum cord compression, did not improve the discriminative ability of the clinical prediction model. In our sample of surgical patients, with clinical and image-evidence of DCM, MRI parameters do not significantly add to

  12. Evaluation of the correlation between disc displacements and degenerative bone changes of the temporomandibular joint by means of magnetic resonance images.

    PubMed

    Dias, Isabela Maddalena; Coelho, Patrícia Rocha; Picorelli Assis, Neuza Maria Souza; Pereira Leite, Fabiola Pessôa; Devito, Karina Lopes

    2012-09-01

    The aim was to evaluate the correlation between disc displacements and degenerative bone changes in magnetic resonance images (MRI) of 112 patients of both genders, with signs and symptoms of temporomandibular disorder. For this purpose, a calibrated examiner evaluated 224 MRI by assigning scores for the displacement of the disc and degenerative bone changes. Disc displacement was found in 58.42% of the temporomandibular joints (TMJs) evaluated. Anterior displacement of the disc with reduction was the most common, occurring in 67.18% cases of joints with disc displacement. Degenerative bone changes were observed in 53.94% of the TMJs analysed. There was significant correlation between disc displacement with reduction and condylar flattening, disc displacement without reduction and condylar flattening, disc displacement without reduction, and associated degenerative bone changes (flattening and erosion, flattening, osteophyte and erosion; flattening and osteophytes, erosion and sclerosis, flattening and sclerosis, flattening, osteophytes and sclerosis). The correlation between advanced cases of disc displacement and the occurrence of degenerative bone changes emphasises the importance of MRI for an accurate diagnosis and development of an appropriate treatment plan and in cases in which clinical examination is not sufficient for these purposes. Copyright © 2012 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Real-time balanced turbo field echo cine-magnetic resonance imaging evaluation of tongue movements during deglutition in subjects with anterior open bite.

    PubMed

    Akin, Erol; Sayin, Mehmet Ozgür; Karaçay, Seniz; Bulakbaşi, Nail

    2006-01-01

    The aim of this study was to evaluate tongue movements in subjects with anterior dental open bites during deglutition by using real-time balanced turbo field echo cine-magnetic resonance imaging. The study included 28 subjects. Two groups were formed according to the presence of anterior open bite (at least 2 mm). The open-bite group (OBG) consisted of 18 patients (14 girls, 4 boys) with a mean age of 14.5 +/- 2.7 years. The control group (CG) consisted of 10 patients (5 girls, 5 boys) with a mean age of 14.5 +/- 2.6 years. We evaluated deglutition during 3 stages: oral (stage 1), pharyngeal (stage 2), and esophageal stage (3). Results indicated that (1) in the OBG, from stage 2 to stage 3, the anterior portion of the tongue dorsum was elevated [corrected] whereas its midportion was lowered [corrected]; (2) in the CG, its posterior portion was lowered [corrected] from stage 2 to stage 3; (3) in the CG, the tongue tip was positioned more posteriorly [corrected] at stage 2 than at stage 1; (4) in the OBG, the tongue tip moved more anteriorly in all stages of deglutition than in the CG. Compensatory tongue functions occur in patients with anterior dental open bites. Dynamic MRI is a promising tool for evaluating swallowing patterns in these patients.

  14. Evaluation of a laminin-alginate biomaterial, adipocytes, and adipocyte-derived stem cells interaction in animal autologous fat grafting model using 7-Tesla magnetic resonance imaging.

    PubMed

    Chen, Yo-Shen; Hsueh, Yu-Sheng; Chen, Yen-Yu; Lo, Cheng-Yu; Tai, Hao-Chih; Lin, Feng-Huei

    2017-01-01

    Biomaterials are often added to autologous fat grafts both as supporting matrices for the grafted adipocytes and as cell carrier for adipose-derived stem cells (ADSCs). This in vivo study used an autologous fat graft model to test a lamininalginate biomaterial, adipocytes, and ADSCs in immune-competent rats. We transplanted different combinations of shredded autologous adipose tissue [designated "A" for adipose tissue]), laminin-alginate beads [designated "B" for bead], and ADSCs [designated "C" for cell]) into the backs of 15 Sprague-Dawley rats. Group A received only adipocytes, Group B received only laminin-alginate beads, Group AB received adipocytes mixed with laminin-alginate beads, Group BC received laminin-alginate beads encapsulating ADSCs, and Group ABC received adipocytes and laminin-alginate beads containing ADSCs. Seven-tesla magnetic resonance imaging was used to evaluate the rats at the 1st, 6th, and 12th weeks after transplantation. At the 12th week, the rats were sacrificed and the implanted materials were retrieved for gross examination and histological evaluation. The results based on MRI, gross evaluation, and histological data all showed that implants in Group ABC had better resorption of the biomaterial, improved survival of the grafted adipocytes, and adipogenic differentiation of ADSCs. Volume retention of grafts in Group ABC (89%) was also significantly greater than those in Group A (58%) (p < 0.01). Our findings support that the combination of shredded adipose tissue with ADSCs in laminin-alginate beads provided the best overall outcome.

  15. Detection of early osteoarthritis in the centrodistal joints of Icelandic horses: Evaluation of radiography and low-field magnetic resonance imaging.

    PubMed

    Ley, C J; Björnsdóttir, S; Ekman, S; Boyde, A; Hansson, K

    2016-01-01

    Validated noninvasive detection methods for early osteoarthritis (OA) are required for OA prevention and early intervention treatment strategies. To evaluate radiography and low-field magnetic resonance imaging (MRI) for the detection of early stage OA osteochondral lesions in equine centrodistal joints using microscopy as the reference standard. Prospective imaging of live horses and imaging and microscopy of cadaver tarsal joints. Centrodistal (distal intertarsal) joints of 38 Icelandic research horses aged 27-29 months were radiographed. Horses were subjected to euthanasia approximately 2 months later and cadaver joints examined with low-field MRI. Osteochondral joint specimens were classified as negative or positive for OA using light microscopy histology or scanning electron microscopy. Radiographs and MRIs were evaluated for osteochondral lesions and results compared with microscopy. Forty-two joints were classified OA positive with microscopy. Associations were detected between microscopic OA and the radiography lesion categories; mineralisation front defect (P<0.0001), joint margin lesion (P<0.0001), central osteophyte (P = 0.03) and the low-field MRI lesion categories; mineralisation front defect (P = 0.01), joint margin lesion (P = 0.02) and articular cartilage lesion (P = 0.0003). The most frequent lesion category detected in microscopic OA positive joints was the mineralisation front defect in radiographs (28/42 OA positive joints, specificity 97%, sensitivity 67%). No significant differences were detected between the sensitivity and specificity of radiography and low-field MRI pooled lesion categories, but radiography was often superior when individual lesion categories were compared. Early stage centrodistal joint OA changes may be detected with radiography and low-field MRI. Detection of mineralisation front defects in radiographs may be a useful screening method for detection of early OA in centrodistal joints of young Icelandic horses. © 2015 EVJ

  16. [Detection and evaluation of cartilage defects in the canine stifle joint - an ex vivo study using high-field magnetic resonance imaging].

    PubMed

    Flatz, K M; Glaser, C; Flatz, W H; Reiser, M F; Matis, U

    2014-01-01

    The aim of our study was to implement and test an imaging protocol for the detection and evaluation of standardised cartilage defects using high-field magnetic resonance imaging (MRI) and to determine its limitations. A total of 84 cartilage defects were created in the femoral condyles of euthanized dogs with a minimum body mass of 25 kg. The cartilage defects had a depth of 0.3 to 1.0 mm and a diameter of 1 to 5 mm. T1-FLASH-3D-WE-sequences with an isotropic voxel size of 0.5 x 0.5 x 0.5 mm and an anisotropic voxel size of 0.3 x 0.3 x 0.8 mm were used. In addition to quantitative evaluation of the cartilage defects, the sig- nal intensities, signal-to-noise ratios and contrast-to-noise ratios of the cartilage were determined. Of special interest were the limita- tions in identifying and delineating the standardised cartilage defects. With the anisotropic voxel size, more cartilage defects were detectable. Our results demonstrated that cartilage defects as small as 3.0 mm in diameter and 0.4 mm in depth were reliably detected using anisotropic settings. Cartilage defects below this size were not reliably detected. We found that for optimal delineation of the joint cartilage and associated defects, a higher in-plane resolution with a larger slice thickness should be used, corresponding to the anisotropic settings employed in this study. For the delineation of larger cartilage defects, both the anisotropic and isotropic imaging methods can be used.

  17. Intra-individual comparison of different gadolinium-based contrast agents in the quantitative evaluation of C6 glioma with dynamic contrast-enhanced magnetic resonance imaging.

    PubMed

    Li, Ying; Liu, Gang; Lou, Xin; Chen, Zhiye; Ma, Lin

    2017-01-01

    This experiment aimed to compare the ionic (Gadodiamide, Gd-DTPA-BMA) and non-ionic (Gadopentetate dimeglumine, Gd-DTPA) gadolinium-based contrast agents (GBCA) in the quantitative evaluation of C6 glioma with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A C6 glioma model was established in 12 Wistar rats, and magnetic resonance (MR) scans were performed six days after tumor implantation. Imaging was performed using a 3.0-T MR scanner with a 7-inch handmade circular coil. Pre-contrast T1 mapping and dynamic contrast-enhanced T1WI after a bolus injection (0.2 mL s(-1)) of GBCA at 0.4 mmol kg(-1) were performed. Each rat received two DCE-MRI scans, 24 h apart. The first and second scans were performed using Gd-DTPA-BMA and Gd-DTPA, respectively. Image data were processed using the Patlak model. Both K (trans) and V p maps were generated. Tumors were manually segmented on all 3D K (trans) and V p maps. Pixel counts and mean values were recorded for use in a paired t-test. Three radiologists independently performed the tumor segmentation and value calculation. The agreements from different observers were subjective to the intra-class correlation coefficient (ICC). Readers demonstrated that the pixel counts of tumors in K (trans) maps were higher with Gd-DTPA-BMA than with Gd-DTPA (P<0.001, all readers). Although the K (trans) values were higher with Gd-DTPA-BMA than with Gd-DTPA, there was no statistical significance (P>0.05, all readers). The pixel counts of tumors in V p maps, as well as V p values, showed no obvious difference between the two agents (P>0.05, all readers). Excellent interobserver measurement reproducibility and reliability were demonstrated in the ICC tests. The Gd-DTPA-BMA contrast agent had significantly higher pixel counts of glioma in the K (trans) maps, and an increased tendency for average K (trans) values, indicating that DCE-MRI with Gd-DTPA-BMA may be more suitable and sensitive for the evaluation of glioma.

  18. Myocardial blood flow quantification for evaluation of coronary artery disease by positron emission tomography, cardiac magnetic resonance imaging, and computed tomography.

    PubMed

    Waller, Alfonso H; Blankstein, Ron; Kwong, Raymond Y; Di Carli, Marcelo F

    2014-05-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging, and computed tomography, and its emerging clinical applications.

  19. Myocardial Blood Flow Quantification for Evaluation of Coronary Artery Disease by Positron Emission Tomography, Cardiac Magnetic Resonance Imaging, and Computed Tomography

    PubMed Central

    Waller, Alfonso H.; Blankstein, Ron; Kwong, Raymond Y.; Di Carli, Marcelo F.

    2014-01-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging and computed tomography, and its emerging clinical applications. PMID:24718671

  20. Pituitary magnetic resonance imaging in Cushing's disease.

    PubMed

    Vitale, Giovanni; Tortora, Fabio; Baldelli, Roberto; Cocchiara, Francesco; Paragliola, Rosa Maria; Sbardella, Emilia; Simeoli, Chiara; Caranci, Ferdinando; Pivonello, Rosario; Colao, Annamaria

    2017-03-01

    Adrenocorticotropin-secreting pituitary tumor represents about 10 % of pituitary adenomas and at the time of diagnosis most of them are microadenomas. Transsphenoidal surgery is the first-line treatment of Cushing's disease and accurate localization of the tumor within the gland is essential for selectively removing the lesion and preserving normal pituitary function. Magnetic resonance imaging is the best imaging modality for the detection of pituitary tumors, but adrenocorticotropin-secreting pituitary microadenomas are not correctly identified in 30-50 % of cases, because of their size, location, and enhancing characteristics. Several recent studies were performed with the purpose of better localizing the adrenocorticotropin-secreting microadenomas through the use in magnetic resonance imaging of specific sequences, reduced contrast medium dose and high-field technology. Therefore, an improved imaging technique for pituitary disease is mandatory in the suspect of Cushing's disease. The aims of this paper are to present an overview of pituitary magnetic resonance imaging in the diagnosis of Cushing's disease and to provide a magnetic resonance imaging protocol to be followed in case of suspicion adrenocorticotropin-secreting pituitary adenoma.

  1. Pharmacologic Effects of Cannabidiol on Acute Reperfused Myocardial Infarction in Rabbits: Evaluated With 3.0T Cardiac Magnetic Resonance Imaging and Histopathology.

    PubMed

    Feng, Yuanbo; Chen, Feng; Yin, Ting; Xia, Qian; Liu, Yewei; Huang, Gang; Zhang, Jian; Oyen, Raymond; Ni, Yicheng

    2015-10-01

    Cannabidiol (CBD) has anti-inflammatory effects. We explored its therapeutic effects on cardiac ischemia-reperfusion injury with an experimental imaging platform. Reperfused acute myocardial infarction (AMI) was induced in rabbits with a 90-minute coronary artery occlusion followed by 24-hour reperfusion. Before reperfusion, rabbits received 2 intravenous doses of 100 μg/kg CBD (n = 10) or vehicle (control, n = 10). Evans blue was intravenously injected for later detection of the AMI core. Cardiac magnetic resonance imaging was performed to evaluate cardiac morphology and function. After euthanasia, blood troponin I (cTnI) was assessed, and the heart was excised and infused with multifunctional red iodized oil dye. The heart was sliced for digital radiography to quantify the perfusion density rate, area at risk (AAR), and myocardial salvage index, followed by histomorphologic staining. Compared with controls, CBD treatment improved systolic wall thickening (P < 0.05), significantly increased blood flow in the AAR (P < 0.05), significantly decreased microvascular obstruction (P < 0.05), increased the perfusion density rate by 1.7-fold, lowered the AMI core/AAR ratio (P < 0.05), and increased the myocardial salvage index (P < 0.05). These improvements were associated with reductions in serum cTnI, cardiac leukocyte infiltration, and myocellular apoptosis (P < 0.05). Thus, CBD therapy reduced AMI size and facilitated restoration of left ventricular function. We demonstrated that this experimental platform has potential theragnostic utility.

  2. Dual-single photon emission computed tomography and contrast-enhanced magnetic resonance imaging to evaluate dissimilar features of apical hypertrophic cardiomyopathy.

    PubMed

    Okayama, Satoshi; Kawata, Hiroyuki; Sung, Ji Hee; Okada, Sadanori; Nishida, Taku; Onoue, Kenji; Soeda, Tsunenari; Uemura, Shiro; Saito, Yoshihiko

    2010-01-01

    Apical hypertrophic cardiomyopathy (HCM) is an uncommon variant of HCM characterized by hypertrophy located in the left ventricular apex that occurs at a rate of about 30% in the Japanese population. Although the prognosis of most patients with apical HCM is relatively benign, it can be poor if apical left ventricular aneurysms develop. However, the mechanism of aneurysmal formation is unclear. We describe two patients with apical HCM and dissimilar findings in 201Thallous chloride ((201)TlCl) and (123)I-betamethyl-p-iodophenyl-pentadecanoic acid ((123)I-BMIPP) dual single-photon emission computed tomography (dual-SPECT), but no myocardial fibrosis on contrast-enhanced magnetic resonance images (MRI). One had apparently normal myocardial perfusion and metabolism, whereas the other had exercise-induced myocardial ischemia and impaired myocardial metabolism. These findings indicated that even apical HCM without myocardial fibrosis is pathophysiologically heterogeneous. Apical HCM has been evaluated by either dual-SPECT or cardiac MRI, but not by both. Thus, a combination of imaging modalities is apparently essential for elucidating the pathophysiology of apical HCM. These dissimilar findings in dual-SPECT might be important in identifying patients with apical HCM who are at high risk of forming aneurysms.

  3. Evaluating middle cerebral artery atherosclerotic lesions in acute ischemic stroke using magnetic resonance T1-weighted 3-dimensional vessel wall imaging.

    PubMed

    Natori, Tatsunori; Sasaki, Makoto; Miyoshi, Mitsuharu; Ohba, Hideki; Katsura, Noriyuki; Yamaguchi, Mao; Narumi, Shinsuke; Kabasawa, Hiroyuki; Kudo, Kohsuke; Ito, Kenji; Terayama, Yasuo

    2014-04-01

    Atherosclerotic lesions in intracranial arteries are a leading cause of ischemic stroke. Magnetic resonance angiography (MRA) is often used to assess atherosclerotic changes by detecting luminal narrowing, whereas it cannot directly visualize atherosclerotic lesions. Here, we used a 3-dimensional vessel wall imaging (3D-VWI) technique to evaluate intracranial arterial wall changes in acute stroke. Eighteen consecutive patients with acute noncardioembolic stroke in the middle cerebral artery (MCA) territory who were prospectively examined with a 1.5-T magnetic resonance scanner were studied. T1-weighted (T1-W) 3D-VWI was obtained using a flow-sensitized 3D fast-spin echo technique. Wall thickening of MCA that suggests atherosclerotic plaques was visually evaluated and the contrast ratio (CR) of signal intensity of the lesions to that of the corpus callosum was calculated and compared with stenotic changes by MRA. Wall thickenings of the MCA ipsilateral and contralateral to the lesion were observed in almost all patients on 3D-VWI (94.4% and 94.4%, respectively), whereas MRA showed stenotic changes of 50% only in 1 patient (5.9%; P < .001). The CR of the thickened wall in the ipsilateral MCA was significantly higher than that in the contralateral MCA (median, .53 and .45, respectively; P = .028), suggesting of unstable plaques consisting of hemorrhage or lipid. The T1-W 3D-VWI can provide direct visualization of atherosclerotic lesions of the intracranial arteries in stroke patients, and it can detect signal change suggestive of unstable plaque. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  4. Magnetic resonance imaging in neurocysticercosis.

    PubMed

    Hernández, Rosa Delia Delgado; Durán, Bernando Boleaga; Lujambio, Perla Salgado

    2014-06-01

    Cysticercosis in one of the most common parasitic infections in the central nervous system. The complex and unpredictable nature of the host immune reaction against cysticercosis as well as the pleomorphism of your injuries make the disease neurocysticercosis interesting and fascinating to study. Imaging studies play an important role in the diagnosis of this disease. Advanced imaging techniques have improved detection and visualization of scolex cysts extraparenchymal spaces.

  5. Evaluation of engraftment of superparamagnetic iron oxide-labeled mesenchymal stem cells using three-dimensional reconstruction of magnetic resonance imaging in photothrombotic cerebral infarction models of rats.

    PubMed

    Shim, Jaehyun; Kwak, Byung Kook; Jung, Jisung; Park, Serah

    2015-01-01

    To evaluate engraftment by visualizing the location of human bone marrow-derived mesenchymal stem cells (hBM-MSCs) three-dimensionally in photothrombotic cerebral infarction (PTCI) models of rats. Magnetic resonance imaging (MRI) of an agarose block containing superparamagnetic iron oxide (SPIO)-labeled hBM-MSCs was performed using a 3.0-T MRI, T2-(T2WI), T2(*)-(T2(*)WI), and susceptibility-weighted images (SWI). PTCI was induced in 6 rats, and 2.5 × 10(5) SPIO-labeled hBM-MSCs were infused through the ipsilateral internal carotid artery (ICA group) or tail vein (IV group). MRI was performed on days 1, 3, 7, and 14 after stem cell injection. Dark signal regions were confirmed using histology. Three-dimensional MRI reconstruction was performed using the clinical workflow solution to evaluate the engraftment of hBM-MSCs. Volumetric analysis of the engraftment was also performed. The volumes of SPIO-labeled hBM-MSCs in the phantom MRI were 129.3, 68.4, and 25.9 µL using SWI, T2(*)WI, and T2WI, respectively. SPIO-labeled hBM-MSCs appeared on day 1 after injection, encircling the cerebral infarction from the ventral side. Dark signal regions matched iron positive cells and human origin (positive) cells. The volume of the engraftment was larger in the ICA group on days 1, 3, and 7, after stem cell injection (p < 0.05 on SWI). SWI was the most sensitive MRI pulse sequence (p < 0.05). The volume of infarction decreased until day 14. The engraftment of SPIO-labeled hBM-MSCs can be visualized and evaluated three-dimensionally in PTCI models of rats. The engraftment volume was larger in the ICA group than IV group on early stage within one week.

  6. Magnetic resonance imaging of skeletal muscle disease.

    PubMed

    Damon, Bruce M; Li, Ke; Bryant, Nathan D

    2016-01-01

    Neuromuscular diseases often exhibit a temporally varying, spatially heterogeneous, and multifaceted pathology. The goals of this chapter are to describe and evaluate the use of quantitative magnetic resonance imaging (MRI) methods to characterize muscle pathology. The following criteria are used for this evaluation: objective measurement of continuously distributed variables; clear and well-understood relationship to the pathology of interest; sensitivity to improvement or worsening of clinical status; and the measurement properties of accuracy and precision. Two major classes of MRI methods meet all of these criteria: (1) MRI methods for measuring muscle contractile volume or cross-sectional area by combining structural MRI and quantitative fat-water MRI; and (2) an MRI method for characterizing the edema caused by inflammation, the measurement of the transverse relaxation time constant (T2). These methods are evaluated with respect to the four criteria listed above and examples from neuromuscular disorders are provided. Finally, these methods are summarized and synthesized and recommendations for additional quantitative MRI developments are made.

  7. Granular convection observed by magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Ehrichs, E. E.; Jaeger, H. M.; Karczmar, Greg S.; Knight, James B.; Kuperman, Vadim Yu.; Nagel, Sidney R.

    1995-03-01

    Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here.

  8. Granular convection observed by magnetic resonance imaging

    SciTech Connect

    Ehrichs, E.E.; Jaeger, H.M.; Knight, J.B.; Nagel, S.R.; Karczmar, G.S.; Kuperman, V.Yu.

    1995-03-17

    Vibrations in a granular material can spontaneously produce convection rolls reminiscent of those seen in fluids. Magnetic resonance imaging provides a sensitive and noninvasive probe for the detection of these convection currents, which have otherwise been difficult to observe. A magnetic resonance imaging study of convection in a column of poppy seeds yielded data about the detailed shape of the convection rolls and the depth dependence of the convection velocity. The velocity was found to decrease exponentially with depth; a simple model for this behavior is presented here. 31 refs., 4 figs.

  9. Magnetic resonance imaging of pelvic endometriosis.

    PubMed

    Méndez Fernández, R; Barrera Ortega, J

    Endometriosis is common in women of reproductive age; it can cause pelvic pain and infertility. It is important to diagnose endometriosis and to thoroughly evaluate its extension, especially when surgical treatment is being considered. Magnetic resonance imaging (MRI) with careful examination technique and interpretation enables more accurate and complete diagnosis and staging than ultrasonography, especially in cases of deep pelvic endometriosis. Furthermore, MRI can identify implants in sites that can be difficult to access in endoscopic or laparoscopic explorations. In this article, we describe the appropriate MRI protocol for the study of pelvic endometriosis and the MRI signs of pelvic organ involvement. It is necessary to know the subtle findings and to look for them so we can ensure that they are not overlooked. We describe clinical grading systems for endometriosis and review the diagnostic efficacy of MRI in comparison with other imaging techniques and surgery. Copyright © 2017 SERAM. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. Wernicke encephalopathy with atypical magnetic resonance imaging.

    PubMed

    Liou, Kuang-Chung; Kuo, Shu-Fan; Chen, Lu-An

    2012-11-01

    Wernicke encephalopathy (WE) is a medical emergency caused by thiamine (vitamin B1) deficiency. Typical clinical manifestations are mental change, ataxia, and ocular abnormalities. Wernicke encephalopathy is an important differential diagnosis in all patients with acute mental change. However, the disorder is greatly underdiagnosed. Clinical suspicion, detailed history taking, and neurologic evaluations are important for early diagnosis. Magnetic resonance imaging (MRI) is currently considered the diagnostic method of choice. Typical MRI findings of WE are symmetrical involvement of medial thalamus, mammillary body, and periaqueductal gray matter. Prompt thiamine supplement is important in avoiding unfavorable outcomes. Here, we report a case of alcoholic WE with typical clinical presentation but with atypical MRI. Axial fluid-attenuated inversion recovery images showing symmetrical hyperintensity lesions in dentate nuclei of cerebellum, olivary bodies, and dorsal pons. Although atypical MRI findings are more common in nonalcoholic WE, it can also occur in alcoholic WE. This article is aimed to highlight the potential pitfalls in diagnosing acute mental change, the importance of clinical suspicion, and early treatment in WE.

  11. Magnetic resonance imaging in Mexico

    NASA Astrophysics Data System (ADS)

    Rodriguez, A. O.; Rojas, R.; Barrios, F. A.

    2001-10-01

    MR imaging has experienced an important growth worldwide and in particular in the USA and Japan. This imaging technique has also shown an important rise in the number of MR imagers in Mexico. However, the development of MRI has followed a typical way of Latin American countries, which is very different from the path shown in the industrialised countries. Despite the fact that Mexico was one the very first countries to install and operate MR imagers in the world, it still lacks of qualified clinical and technical personnel. Since the first MR scanner started to operate, the number of units has grown at a moderate space that now sums up approximately 60 system installed nationwide. Nevertheless, there are no official records of the number of MR units operating, physicians and technicians involved in this imaging modality. The MRI market is dominated by two important companies: General Electric (approximately 51%) and Siemens (approximately 17.5%), the rest is shared by other five companies. According to the field intensity, medium-field systems (0.5 Tesla) represent 60% while a further 35% are 1.0 T or higher. Almost all of these units are in private hospitals and clinics: there is no high-field MR imagers in any public hospital. Because the political changes in the country, a new public plan for health care is still in the process and will be published soon this year. This plan will be determined by the new Congress. North American Free Trade Agreement (NAFTA) and president Fox. Experience acquired in the past shows that the demand for qualified professionals will grow in the new future. Therefore, systematic training of clinical and technical professionals will be in high demand to meet the needs of this technique. The National University (UNAM) and the Metropolitan University (UAM-Iztapalapa) are collaborating with diverse clinical groups in private facilities to create a systematic training program and carry out research and development in MRI

  12. Simultaneous PET/MRI with (13)C magnetic resonance spectroscopic imaging (hyperPET): phantom-based evaluation of PET quantification.

    PubMed

    Hansen, Adam E; Andersen, Flemming L; Henriksen, Sarah T; Vignaud, Alexandre; Ardenkjaer-Larsen, Jan H; Højgaard, Liselotte; Kjaer, Andreas; Klausen, Thomas L

    2016-12-01

    Integrated PET/MRI with hyperpolarized (13)C magnetic resonance spectroscopic imaging ((13)C-MRSI) offers simultaneous, dual-modality metabolic imaging. A prerequisite for the use of simultaneous imaging is the absence of interference between the two modalities. This has been documented for a clinical whole-body system using simultaneous (1)H-MRI and PET but never for (13)C-MRSI and PET. Here, the feasibility of simultaneous PET and (13)C-MRSI as well as hyperpolarized (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is evaluated using phantom experiments. Combined PET and (13)C-MRSI phantoms including a NEMA [(18)F]-FDG phantom, (13)C-acetate and (13)C-urea sources, and hyperpolarized (13)C-pyruvate were imaged repeatedly with PET and/or (13)C-MRSI. Measurements evaluated for interference effects included PET activity values in the largest sphere and a background region; total number of PET trues; and (13)C-MRSI signal-to-noise ratio (SNR) for urea and acetate phantoms. Differences between measurement conditions were evaluated using t tests. PET and (13)C-MRSI data acquisition could be performed simultaneously without any discernible artifacts. The average difference in PET activity between acquisitions with and without simultaneous (13)C-MRSI was 0.83 (largest sphere) and -0.76 % (background). The average difference in net trues was -0.01 %. The average difference in (13)C-MRSI SNR between acquisitions with and without simultaneous PET ranged from -2.28 to 1.21 % for all phantoms and measurement conditions. No differences were significant. The system was capable of (13)C-MRSI of hyperpolarized (13)C-pyruvate. Simultaneous PET and (13)C-MRSI in an integrated whole-body PET/MRI hybrid scanner is feasible. Phantom experiments showed that possible interference effects introduced by acquiring data from the two modalities simultaneously are small and non-significant. Further experiments can now investigate the benefits of simultaneous PET and

  13. An Audit to Evaluate the Image Quality of Magnetic Resonance of Knee at Radiology Department of a Tertiary Care Hospital.

    PubMed

    Mansoor, Ali; Ramzan, Amaila; Chaudhary, Aamer Nadeem

    2017-04-01

    light of recommendations of ACR. Aclinical audit. Department of Radiology, Jinnah Hospital, Lahore, from August 2015 to February 2016. Scans of 20 patients who underwent MRI of knee in August 2015 were studied retrospectively to assess the quality of images obtained in the first audit. Based on the findings of this audit, recommendations were made and re audit was done 6 months later in February 2016 to look for improvement in local practice. In the first audit, images were acquired in all the three necessary planes and the sagittal and coronal images had appropriate slice thickness, interslice gap as well as adequate anatomical coverage in all the patients. However, FOV (field of view) was appropriately set in 66% of cases in axial plane, 5% in sagittal plane, and 0% in coronal plane. Also, the anatomical coverage was not upto the mark in axial plane with 13 studies (66%) having adequate superior coverage, and 16 cases (80%) having recommended inferior anatomical coverage. The re audit performed 6 months later showed improvement with 100% compliance to standards. The first audit showed many shortcomings in acquiring of MRI data in patients undergoing knee MRI with FOV requiring a decrease in all planes and anatomical coverage increase in axial plane. These recommendations were made in departmental meetings and re-audit was done after 6 months. This second audit showed 100 % compliance.

  14. Evaluate the early changes of myocardial fibers in rhesus monkey during sub-acute stage of myocardial infarction using diffusion tensor magnetic resonance imaging.

    PubMed

    Wang, Yuqing; Cai, Wei; Wang, Lei; Xia, Rui

    2016-05-01

    The deterioration of cardiac mechanical function starts from the micro-alterations in the myocardial fibers after myocardial infarction (MI) due to the heart beats derived from the systole and diastole of the myocardial fibers. So, we want to evaluate quantitatively the early changes of myocardial fibers in rhesus monkey during sub-acute MI stage. Three fixed hearts with infarction after left anterior descending coronary artery ligation for 7days and eight age-matched intact controls were scanned by ex-vivo diffusion tensor magnetic resonance imaging (DT-MRI) to measure apparent diffusion coefficient (ADC), fractional anisotropy (FA) and helix angle (HA). In comparison with healthy controls, FA and transmural range of HA in MI regions showed a significant reduction whereas ADC showed a significant increment (p<0.01). The double-helix myocardial fibers shifted further to left-handed helix around the infarcted and adjacent myocardium but shifted further to right-handed helix in remote myocardium. HA is sensitive to evaluate quantitatively the early changes of myocardial fibers in sub-acute MI rhesus monkeys. The myocardial fibers in normal monkeys are similar to those in normal humans, suggesting that early changes of myocardial fibers in sub-acute MI monkeys can contribute to more accurately understand those in patients suffering sub-acute MI. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. The utility of magnetic resonance imaging in addition to computed tomography scans in the evaluation of cervical spine injuries: a study of obtunded blunt trauma patients.

    PubMed

    Lau, Bernard Puang Huh; Hey, Hwee Weng Dennis; Lau, Eugene Tze-Chun; Nee, Pei Yi; Tan, Kimberly-Anne; Tan, Wah Tze

    2017-10-09

    Evidence guiding the use of CT and MRI scans in blunt trauma patients who are obtunded remains controversial. This study aims to determine and predict if computed tomography (CT) scans alone can be performed without risking oversight of substantial injuries found on follow-up magnetic resonance imaging (MRI). This is a retrospective cohort study of 63 blunt trauma patients with a Glasgow Coma Scale of < 8. Data were collated from electronic medical records and included patient demographics, premorbid mobility, mechanism of injury, suspected level of injury and neurological examination findings. Patients were urgently evaluated using CT scans, followed by non-contrast MRI scans within 48 h of admission. The accuracy of CT scan was evaluated using MRI as a reference. Adjusted multivariable analysis was also performed to identify predictors for findings detected on MRI but not on CT. The mean age of patients was 42.3 years and 90.5% were males. CT scans had a high specificity of 100% and sensitivity of 87.2%. Predictors of MRI abnormalities include females, patients with relatively milder mechanisms of injury, patients with suspected thoracic spine injury, and CT scan findings of facet dislocation and intracranial haemorrhage. There was no predictor for spinal cord oedema. MRI should be performed in the presence of the aforementioned predictive factors and in the presence of neurological deficits. Otherwise, patients can be treated medically without the fear of missing a substantial cervical injury.

  16. Utilizing magnetic resonance imaging logs, open hole logs and sidewall core analyses to evaluate shaly sands for water-free production

    SciTech Connect

    Taylor, D.; Morganti, J.; White, H.

    1995-06-01

    NMR logging using the new C series Magnetic Resonance Imaging Logging (MRIL){trademark} is rapidly enhancing formation evaluation throughout the industry. By measuring irreducible water saturations, permeability and effective porosities, MRIL data can help petrophysicists evaluate low resistivity pays. In these instances, conventional open hole logs may not define all of the pay intervals. MRIL can also minimize unnecessary completions in zones of potentially high water-cut. This case study will briefly discuss MRIL tool theory and log presentations used with the conventional logs and sidewall cores. SEM analysis will show a good correlation of varying grain size sands with the T{sub 2} distribution and bulk volume irreducible from MRIL. Discussions of each well in the study area will show how water-free production zones were defined. Because the MRIL data was not recorded on one of the wells, the advanced petrophysical program HORIZON was used to predict the MRIL bulk volume irreducible and effective porosity to estimate productive zones. Discussion of additional formation characteristics, completion procedures, actual production and predicted producibility of the shaly sands will be presented.

  17. Are cardiac magnetic resonance imaging and radionuclide ventriculography good options against echocardiography for evaluation of anthracycline induced chronic cardiotoxicity in childhood cancer survivors?

    PubMed

    Basar, Evic Zeynep; Corapcioglu, Funda; Babaoglu, Kadir; Anik, Yonca; Gorur Daglioz, Gozde; Dedeoglu, Reyhan

    2014-04-01

    Anthracyclines are widely used for the treatment of solid tumors in pediatric oncology. However, their uses may be limited by progressive chronic cardiotoxicity related to the cumulative dosage. The aims of this study are to compare diagnostic techniques and prepare an algorithm for diagnosis of anthracycline induced chronic cardiotoxicity. The patients were evaluated according to age, sex, time elapsed since the last dose of anthracycline treatment, presence of cardiovascular symptoms, follow-up duration, type of anthracycline, cumulative anthracycline dose, and concomitant mediastinal radiation therapy. Late subclinical cardiotoxicity was detected by history, physical examination, electrocardiography (ECG), Holter monitor, echocardiography (ECHO), radionuclide ventriculography (MUGA), and cardiac magnetic resonance imaging (MRI). Thirty-seven male and 19 female patients with a median age of 11.2 ± 4.6 (range, 3.5-22.0) years were included in the study. Patients were grouped according to cumulative anthracycline doses. Subclinical cardiac dysfunction was detected in 20 patients by at least one of ECHO, MRI or MUGA after anthracycline chemotherapy. We revealed that other than ECHO, MRI and MUGA have high clinical importance for evaluating subclinical late cardiac complications in children treated with anthracyclines.

  18. Review: Magnetic resonance imaging techniques in ophthalmology

    PubMed Central

    Fagan, Andrew J.

    2012-01-01

    Imaging the eye with magnetic resonance imaging (MRI) has proved difficult due to the eye’s propensity to move involuntarily over typical imaging timescales, obscuring the fine structure in the eye due to the resulting motion artifacts. However, advances in MRI technology help to mitigate such drawbacks, enabling the acquisition of high spatiotemporal resolution images with a variety of contrast mechanisms. This review aims to classify the MRI techniques used to date in clinical and preclinical ophthalmologic studies, describing the qualitative and quantitative information that may be extracted and how this may inform on ocular pathophysiology. PMID:23112569

  19. Optimal magnetic resonance imaging of the brain.

    PubMed

    Robertson, Ian

    2011-01-01

    Quality magnetic resonance (MR) imaging is complex and requires optimization of many technical factors. The most important factors are: magnet field and gradient strengths, coil selection, receiver bandwidth, field of view and image matrix size, number of excitations, slice thickness, image weighting and contrast, imaging planes and the direction of the phase, and frequency gradients. The ability to augment a standard MR study with additional sequences, and the need to ensure the completed study is comprehensive and robust must be balanced against the time the patient spends under anesthesia in the magnet.

  20. Magnetic Resonance Imaging (MRI) -- Head

    MedlinePlus

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

  1. Evaluation of the translational and rotational forces acting on a highly ferromagnetic orthopedic spinal implant in magnetic resonance imaging.

    PubMed

    McComb, Christie; Allan, David; Condon, Barrie

    2009-02-01

    To assess the translational and rotational forces acting on a highly ferromagnetic orthopedic spinal implant in 1.5T and 3.0T magnetic resonance (MR) systems. The translational forces and rotational forces, or torques, acting on the implant were measured using existing methods and assessed using the guidelines produced by the American Society for Testing and Materials (ASTM). The measured translational forces were many times greater than for any other orthopedic implant previously recorded in the literature and, based on deflection angle criteria, would be considered unsafe in both MR systems. However, due to the rigid fixation of orthopedic implants in bone, implant migration is considered highly unlikely. Several constituent components of the implant were subjected to large torques, in some cases an order of magnitude greater than the corresponding torque due to gravity. However, the counterbalancing effect of the configuration of the combined implant results in a net torque that is less than the torque due to gravity. The translational and rotational forces acting on the implant in both 1.5T and 3.0T MR systems are substantial, but based on theoretical considerations are unlikely to result in implant migration or rotation.

  2. Coronary Microembolization with Normal Epicardial Coronary Arteries and No Visible Infarcts on Nitrobluetetrazolium Chloride-Stained Specimens: Evaluation with Cardiac Magnetic Resonance Imaging in a Swine Model

    PubMed Central

    Jin, Hang; Yun, Hong; Ma, Jianying; Chen, Zhangwei; Chang, Shufu

    2016-01-01

    Objective To assess magnetic resonance imaging (MRI) features of coronary microembolization in a swine model induced by small-sized microemboli, which may cause microinfarcts invisible to the naked eye. Materials and Methods Eleven pigs underwent intracoronary injection of small-sized microspheres (42 µm) and catheter coronary angiography was obtained before and after microembolization. Cardiac MRI and measurement of cardiac troponin T (cTnT) were performed at baseline, 6 hours, and 1 week after microembolization. Postmortem evaluation was performed after completion of the imaging studies. Results Coronary angiography pre- and post-microembolization revealed normal epicardial coronary arteries. Systolic wall thickening of the microembolized regions decreased significantly from 42.6 ± 2.0% at baseline to 20.3 ± 2.3% at 6 hours and 31.5 ± 2.1% at 1 week after coronary microembolization (p < 0.001 for both). First-pass perfusion defect was visualized at 6 hours but the extent was largely decreased at 1 week. Delayed contrast enhancement MRI (DE-MRI) demonstrated hyperenhancement within the target area at 6 hours but not at 1 week. The microinfarcts on gross specimen stained with nitrobluetetrazolium chloride were invisible to the naked eye and only detectable microscopically. Increased cTnT was observed at 6 hours and 1 week after microembolization. Conclusion Coronary microembolization induced by a certain load of small-sized microemboli may result in microinfarcts invisible to the naked eye with normal epicardial coronary arteries. MRI features of myocardial impairment secondary to such microembolization include the decline in left ventricular function and myocardial perfusion at cine and first-pass perfusion imaging, and transient hyperenhancement at DE-MRI. PMID:26798220

  3. Magnetic resonance imaging based morphologic evaluation of the pineal gland for suspected pineoblastoma in retinoblastoma patients and age-matched controls.

    PubMed

    Pham, Thi Thai Hien; Siebert, Eberhard; Asbach, Patrick; Willerding, Gregor; Erb-Eigner, Katharina

    2015-12-15

    The purpose of this study was to evaluate the morphologic magnetic resonance imaging (MRI) characteristics of the pineal gland in retinoblastoma (Rb) patients without and with pineoblastoma in comparison to age-matched controls to improve early identification of pineoblastomas (trilateral retinoblastoma, TRb). 80 patients with retinoblastoma and 80 age-matched controls who had undergone brain MRI were included in this retrospective institutional review board approved cohort study. Two readers analyzed the following MR characteristics of the pineal gland: signal intensity on T1- and T2-weighted images, enhancement pattern, delineation of the gland, presence of cystic component, size of pineal gland and size of pineal cysts, respectively. A third reader assessed all images for the presence or absence of pineoblastoma. 3 patients were positive (TRb cohort) and 77 negative for pineoblastoma (non-TRb cohort). The mean maximum diameter of the pineal gland was 6.4mm in Rb patients and 6.3mm in age-matched controls. The mean volume of the pineal gland in Rb patients was 93.1mm(3) and was 87.6mm(3) in age-matched controls. Considering all available MRI scans the mean maximum diameter of the pineal gland in TRb patients was 11.2mm and the mean volume in TRb patients was 453.3mm(3). The third reader identified pineoblastomas with a sensitivity of 100% (3 of 3) and a specificity of 94% (72 of 77). Our non-TRb patients did not show significant differences in the size of the pineal gland and pineal gland cysts compared to age-matched controls. The presented data can serve as a reference for the volume of normal pineal glands and pineal cysts in the diagnostic work-up of Rb patients with suspected pineoblastoma. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. RETROSPECTIVE STUDY EVALUATING ASSOCIATIONS BETWEEN MIDLINE BRAIN SHIFT ON MAGNETIC RESONANCE IMAGING AND SURVIVAL IN DOGS DIAGNOSED WITH MENINGOENCEPHALITIS OF UNKNOWN ETIOLOGY.

    PubMed

    Oliphant, Bonnie J; Barnes Heller, Heidi L; White, Jennifer M

    2017-01-01

    Difficulty has been encountered when trying to identify ante mortem prognostic indicators for dogs with meningoencephalitis of unknown etiology (MUE). Identifying MRI imaging parameters associated with prognosis may impact treatment decision-making for clinician and owner. Our hypotheses for this retrospective cohort study are that dogs diagnosed with MUE that had midline shift on brain MRI would have a poorer survival compared to dogs without midline shift; and that younger age, lower weight, and low cerebrospinal fluid (CSF) cell count would be correlated with improved survival. Medical records were reviewed from two institutions. Inclusion criteria included: clinical signs referable to intracranial disease, brain MRI at presentation, abnormal CSF analysis, and negative infectious disease testing. Magnetic resonance imaging scans were evaluated for midline shift using the T2-weighted transverse image at the interthalamic adhesion and at the site of maximal deviation. Fifty-two dogs met the inclusion criteria. Median midline deviation was 0.12 cm. Median survival for dogs with no shift was 906 days and with shift was 84 days. Survival was not significantly different between groups (P = 0.11). This remained true when correcting for age (P = 0.22) and CSF TNCC (total nucleated cell count) (P = 0.12). Age at the time of diagnosis (P = 0.02) and CSF TNCC (P = 0.03) were significantly associated with survival. Cerebrospinal fluid protein value (P = 0.84) and weight (P = 0.82) were not significantly associated with survival. In this study of 52 dogs with MUE, MRI evidence of midline brain shift between 0.04 and 0.3 cm at the level of the interthalamic adhesion was not associated with shorter survival. © 2016 American College of Veterinary Radiology.

  5. Terbium-based time-gated Förster resonance energy transfer imaging for evaluating protein-protein interactions on cell membranes.

    PubMed

    Lindén, Stina; Singh, Manish Kumar; Wegner, K David; Regairaz, Marie; Dautry, François; Treussart, François; Hildebrandt, Niko

    2015-03-21

    Fluorescence imaging of cells and subcellular compartments is an essential tool to investigate biological processes and to evaluate the development and progression of diseases. In particular, protein-protein interactions can be monitored by Förster resonance energy transfer (FRET) between two proximal fluorophores that are attached to specific recognition biomolecules such as antibodies. We investigated the membrane expression of E- and N-cadherins in three different cell lines used as model systems to study epithelial to mesenchymal transition (EMT) and a possible detection of circulating tumour cells (CTCs). EMT is a key process in cancer metastasis, during which epithelial markers (such as E-cadherin) are down-regulated in the primary tumour whereas mesenchymal markers (such as N-cadherin) are up-regulated, leading to enhanced cell motility, intravasation, and appearance of CTCs. Various FRET donor-acceptor pairs and protein recognition strategies were utilized, in which Lumi4-Tb terbium complexes (Tb) and different organic dyes were conjugated to several distinct E- and N-cadherin-specific antibodies. Pulsed excitation of Tb at low repetition rates (100 Hz) and time-gated (TG) imaging of both the Tb-donor and the dye-acceptor photoluminescence (PL) allowed efficient detection of the EMT markers as well as FRET in the case of sufficient donor-acceptor proximity. Efficient FRET was observed only between two E-cadherin-specific antibodies and further experiments indicated that these antibodies recognized the same E-cadherin molecule, suggesting a limited accessibility of cadherins when they are clustered at adherens junctions. The investigated Tb-to-dye FRET systems provided reduced photobleaching compared to the AlexaFluor 488-568 donor-acceptor pair. Our results demonstrate the applicability and advantages of Tb-based TG FRET for efficient and stable imaging of antibody-antibody interactions on different cell lines. They also reveal the limitations of

  6. Dapsone improves functional deficit and diminishes brain damage evaluated by 3-Tesla magnetic resonance image after transient cerebral ischemia and reperfusion in rats.

    PubMed

    Diaz-Ruiz, Araceli; Roldan-Valadez, Ernesto; Ortiz-Plata, Alma; Mondragón-Lozano, Rodrigo; Heras-Romero, Yessica; Mendez-Armenta, Marisela; Osorio-Rico, Laura; Nava-Ruiz, Concepción; Ríos, Camilo

    2016-09-01

    Stroke is a frequent cause of death and the first of disability in the world population. We have shown that dapsone acts as an antioxidant, antiinflammatory and antiapoptotic agent after brain Ischemia reperfusion (I/R) in rats; however, its therapeutic efficacy, measured by imaging has not been characterized. In this context, the aim of this study was to evaluate the neuroprotective effect of dapsone by magnetic resonance imaging (MRI) and to correlate imaging markers with motor function and oxidative stress after transient cerebral ischemia and reperfusion (I/R). We used male rats throughout the experiment. Functional deficit after I/R was assessed by using Longa scale. The area of brain tissue damage was measured by histology. The nuclear factor erythroid 2-related factor 2 (Nrf-2) and the amount of reactive oxygen species (ROS) were measured as biomarkers of oxidative stress. Finally, difussion tensor MRI was employed to measure the fractional anisotropy (FA), as a MRI marker of the pathophysiologic brain status. Results showed a better functional recovery and less damaged tissue in animals treated with dapsone vs control group. The values of FA were higher in animals receiving treatment, indicating a better preservation of brain structure. At early stages of the damage, dapsone was able to reduce both oxidative markers (Nrf-2 and ROS). Our findings provide new evidence for the efficacy of dapsone when administered during the acute phase after I/R and that quantitative sequences of MRI are useful for characterizing its potential therapeutic benefits after stroke. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Magnetic resonance imaging in inflammatory rheumatoid diseases.

    PubMed

    Sudoł-Szopińska, Iwona; Mróz, Joanna; Ostrowska, Monika; Kwiatkowska, Brygida

    2016-01-01

    Magnetic resonance (MR) is used more and more frequently to diagnose changes in the musculoskeletal system in the course of rheumatic diseases, at their initial assessment, for treatment monitoring and for identification of complications. The article presents the history of magnetic resonance imaging, the basic principles underlying its operation as well as types of magnets, coils and MRI protocols used in the diagnostic process of rheumatic diseases. It enumerates advantages and disadvantages of individual MRI scanners. The principles of MRI coil operation are explained, and the sequences used for MR image analysis are described, particularly in terms of their application in rheumatology, including T1-, T2-, PD-weighted, STIR/TIRM and contrast-enhanced T1-weighted images. Furthermore, views on the need to use contrast agents to optimise diagnosis, particularly in synovitis-like changes, are presented. Finally, methods for the assessment of MR images are listed, including the semi-quantitative method by RAMRIS and quantitative dynamic examination.

  8. Three-dimensional contrast enhanced ultrasound score and dynamic contrast-enhanced magnetic resonance imaging score in evaluating breast tumor angiogenesis: correlation with biological factors.

    PubMed

    Jia, Wan-Ru; Chai, Wei-Min; Tang, Lei; Wang, Yi; Fei, Xiao-Chun; Han, Bao-San; Chen, Man

    2014-07-01

    To explore the clinical value of three-dimensional contrast enhanced ultrasound (3D-CEUS) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) score systems in evaluating breast tumor angiogenesis by comparing their diagnostic efficacy and correlation with biological factors. 3D-CEUS was performed in 183 patients with breast tumors by Esaote Mylab90 with SonoVue (Bracco, Italy), DCE-MRI was performed on a dedicated breast magnetic resonance imaging (DBMRI) system (Aurora Dedicated Breast MRI Systems, USA) with a dedicated breast coil. 3D-CEUS and DCE-MRI score systems were created based on tumor perfusion and vascular characteristics. Microvessel density (MVD), vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMP-2, MMP-9) expression were measured by immunohistochemistry. Pathological results showed 35 benign and 148 malignant breast tumors. MVD (P=0.000, r=0.76), VEGF (P=0.000, r=0.55), MMP-2 (P=0.000, r=0.39) and MMP-9 (P=0.000, r=0.41) expression were all significantly different between benignity and malignancy. Regarding 3D-CEUS 4 points as cutoff value, the sensitivity, specificity and accuracy were 85.1%, 94.3% and 86.9%, respectively, and correlated well with MVD (P=0.000, r=0.50), VEGF (P=0.000, r=0.50), MMP-2 (P=0.000, r=0.50) and MMP-9 (P=0.000, r=0.66). Taking DCE-MRI 5 points as cutoff value, the sensitivity, specificity and accuracy were 86.5%, 94.3% and 88.0%, respectively and also correlated well with MVD (P=0.000, r=0.52), VEGF (P=0.000, r=0.44), MMP-2 (P=0.000, r=0.42) and MMP-9 (P=0.000, r=0.35). 3D-CEUS score system displays inspiring diagnostic performance and good agreement with DCE-MRI scoring. Moreover, both score systems correlate well with MVD, VEGF, MMP-2 and MMP-9 expression, and thus have great potentials in tumor angiogenesis evaluation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  9. Improving magnetic resonance imaging (MRI) examinations: Development and evaluation of an intervention to reduce movement in scanners and facilitate scan completion.

    PubMed

    Powell, Rachael; Ahmad, Mahadir; Gilbert, Fiona J; Brian, David; Johnston, Marie

    2015-09-01

    The movement of patients in magnetic resonance imaging (MRI) scanners results in motion artefacts which impair image quality. Non-completion of scans leads to delay in diagnosis and increased costs. This study aimed to develop and evaluate an intervention to enable patients to stay still in MRI scanners (reducing motion artefacts) and to enhance scan completion. Successful scan outcome was deemed to be completing the scan with no motion artefacts. Previous research indicated self-efficacy to predict successful scan outcome, and interviews with patients identified a need for procedural and sensory information to facilitate successful scan behaviour. A DVD intervention was developed which targeted self-efficacy and included procedural and sensory information. It was successfully piloted with 10 patients and then evaluated in a randomized controlled trial compared with the standard hospital information leaflet (intervention group N = 41; control group N = 42). The clinic radiographer, who was blind to group allocation, rated MRI scans for motion artefact and recorded whether the participant completed the scan; participants completed MRI self-efficacy and anxiety measures. Only one participant reported not finding the DVD useful. Thirty-five participants in the intervention group and 23 in the control group completed scans and had no motion artefacts, χ(2) (1, 83) = 7.84, p < .001 (relative risk of an unsatisfactory outcome in the control group/intervention group = 3.09). The intervention effect was mediated by self-efficacy. The DVD intervention was efficacious and warrants further research to examine generalizability. © 2015 The British Psychological Society.

  10. Magnetic resonance imaging for prostate cancer clinical application

    PubMed Central

    Li, Bing; Du, Yong; Huang, Yayong; Meng, Jun; Xiao, Dongmei

    2013-01-01

    As prostate cancer is a biologically heterogeneous disease for which a variety of treatment options are available, the major objective of prostate cancer imaging is to achieve more precise disease characterization. In clinical practice, magnetic resonance imaging (MRI) is one of the imaging tools for the evaluation of prostate cancer, the fusion of MRI or dynamic contrast-enhanced MRI (DCE-MRI) with magnetic resonance spectroscopic imaging (MRSI) is improving the evaluation of cancer location, size, and extent, while providing an indication of tumor aggressiveness. This review summarizes the role of MRI in the application of prostate cancer and describes molecular MRI techniques (including MRSI and DCE-MRI) for aiding prostate cancer management. PMID:23592906

  11. Fetal Cerebral Magnetic Resonance Imaging Beyond Morphology.

    PubMed

    Jakab, András; Pogledic, Ivana; Schwartz, Ernst; Gruber, Gerlinde; Mitter, Christian; Brugger, Peter C; Langs, Georg; Schöpf, Veronika; Kasprian, Gregor; Prayer, Daniela

    2015-12-01

    The recent technological advancement of fast magnetic resonance imaging (MRI) sequences allowed the inclusion of diffusion tensor imaging, functional MRI, and proton MR spectroscopy in prenatal imaging protocols. These methods provide information beyond morphology and hold the key to improving several fields of human neuroscience and clinical diagnostics. Our review introduces the fundamental works that enabled these imaging techniques, and also highlights the most recent contributions to this emerging field of prenatal diagnostics, such as the structural and functional connectomic approach. We introduce the advanced image processing approaches that are extensively used to tackle fetal or maternal movement-related image artifacts, and which are necessary for the optimal interpretation of such imaging data. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. A Correlative Classification Study of Schizophrenic Patients with Results of Clinical Evaluation and Structural Magnetic Resonance Images

    PubMed Central

    Chu, Wen-Lin; Jian, Bo-Lin; Hsu, Chih-Yao

    2016-01-01

    Patients with schizophrenia suffer from symptoms such as hallucination and delusion. There are currently a number of publications that discuss the treatment, diagnosis, prognosis, and damage in schizophrenia. This study utilized joint independent component analysis to process the images of GMV and WMV and incorporated the Wisconsin card sorting test (WCST) and the positive and negative syndrome scale (PANSS) to examine the correlation of obtained brain characteristics. We also used PANSS score to classify schizophrenic patients into acute and subacute cases, to analyze the brain structure differences. Finally, we used brain structure images and the error rate of the WCST as eigenvalues in support vector machine learning and classification. The results of this study showed that the frontal and temporal lobes of a normal brain are more apparent than those of a schizophrenia brain. The highest level of classification recognition reached 91.575%, indicating that the WCST error rate and characteristic changes in brain structure volume can be used to effectively distinguish schizophrenia and normal brains. Similarly, this result confirmed that the WCST and brain structure volume are correlated with the differences between schizophrenia and normal participants. PMID:27843197

  13. Characterisation and evaluation of paramagnetic fluorine labelled glycol chitosan conjugates for (19)F and (1)H magnetic resonance imaging.

    PubMed

    De Luca, Elena; Harvey, Peter; Chalmers, Kirsten H; Mishra, Anurag; Senanayake, P Kanthi; Wilson, J Ian; Botta, Mauro; Fekete, Marianna; Blamire, Andrew M; Parker, David

    2014-02-01

    Medium molecular weight glycol chitosan conjugates have been prepared, linked by an amide bond to paramagnetic Gd(III), Ho(III) and Dy(III) macrocyclic complexes in which a trifluoromethyl reporter group is located 6.5 Å from the paramagnetic centre. The faster relaxation of the observed nucleus allows modified pulse sequences to be used with shorter acquisition times. The polydisperse materials have been characterised by gel permeation chromatography, revealing an average molecular weight on the order of 13,800 (Gd), 14,600 (Dy) and 16,200 (Ho), consistent with the presence of 8.5, 9.5 and 13 complexes, respectively. The gadolinium conjugate was prepared for both a q = 1 monoamide tricarboxylate conjugate (r1p 11.2 mM(-1) s(-1), 310 K, 1.4 T) and a q = 0 triphosphinate system, and conventional contrast-enhanced proton MRI studies at 7 T were undertaken in mice bearing an HT-29 or an HCT-116 colorectal tumour xenograft (17 μmol/kg). Enhanced contrast was observed following injection in the tail vein in tumour tissue, with uptake also evident in the liver and kidney with a tumour-to-liver ratio of 2:1 at 13 min, and large amounts in the kidney and bladder consistent with predominant renal clearance. Parallel experiments observing the (19)F resonance in the holmium conjugate complex using a surface coil did not succeed owing to its high R2 value (750 Hz, 7 T). However, the fluorine signal in the dysprosium triphosphinate chitosan conjugate [R1/R2 = 0.6 and R1 = 145 Hz (7 T)] was sharper and could be observed in vivo at -65.7 ppm, following intravenous tail vein injection of a dose of 34 μmol/kg.

  14. Comparison of cardiovascular magnetic resonance and single-photon emission computed tomography in women with suspected coronary artery disease from the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC) Trial.

    PubMed

    Greenwood, John P; Motwani, Manish; Maredia, Neil; Brown, Julia M; Everett, Colin C; Nixon, Jane; Bijsterveld, Petra; Dickinson, Catherine J; Ball, Stephen G; Plein, Sven

    2014-03-11

    Coronary artery disease is the leading cause of death in women, and underdiagnosis contributes to the high mortality. This study compared the sex-specific diagnostic performance of cardiovascular magnetic resonance (CMR) and single-photon emission computed tomography (SPECT). A total of 235 women and 393 men with suspected angina underwent CMR, SPECT, and x-ray angiography as part of the Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease (CE-MARC) study. CMR comprised adenosine stress/rest perfusion, cine imaging, late gadolinium enhancement, and magnetic resonance coronary angiography. Gated adenosine stress/rest SPECT was performed with (99m)Tc-tetrofosmin. For CMR, the sensitivity in women and men was similar (88.7% versus 85.6%; P=0.57), as was the specificity (83.5% versus 82.8%; P=0.86). For SPECT, the sensitivity was significantly worse in women than in men (50.9% versus 70.8%; P=0.007), but the specificities were similar (84.1% versus 81.3%; P=0.48). The sensitivity in both the female and male groups was significantly higher with CMR than SPECT (P<0.0001 for both), but the specificity was similar (P=0.77 and P=1.00, respectively). For perfusion-only components, CMR outperformed SPECT in women (area under the curve, 0.90 versus 0.67; P<0.0001) and in men (area under the curve, 0.89 versus 0.74; P<0.0001). Diagnostic accuracy was similar in both sexes with perfusion CMR (P=1.00) but was significantly worse in women with SPECT (P<0.0001). In both sexes, CMR has greater sensitivity than SPECT. Unlike SPECT, there are no significant sex differences in the diagnostic performance of CMR. These findings, plus an absence of ionizing radiation exposure, mean that CMR should be more widely adopted in women with suspected coronary artery disease. http://www.controlled-trials.com. Unique identifier: ISRCTN77246133.

  15. Neurosurgical uses for intraprocedural magnetic resonance imaging.

    PubMed

    Mutchnick, Ian S; Moriarty, Thomas M

    2005-10-01

    Neurosurgical procedures demand precision, and efforts to create accurate neurosurgical navigation have been central to the profession through its history. Magnetic resonance image (MRI)-guided navigation offers the possibility of real-time, image-based stereotactic information for the neurosurgeon, which makes possible a number of diagnostic and therapeutic procedures. This article will review both current options for intraoperative MRI operative suite arrangements and the current therapeutic/diagnostic uses of intraoperative MRI.

  16. Role of magnetic resonance imaging in musculoskeletal trauma.

    PubMed

    Ahn, Joong Mo; El-Khoury, Georges Y

    2007-06-01

    The unique ability of magnetic resonance (MR) imaging to visualize injuries of bone, cartilage, bone marrow, and supporting soft tissue structure makes it ideally suited for the evaluation of musculoskeletal trauma. Magnetic resonance imaging also offers exquisitely detailed anatomical information on the musculoskeletal system. The widespread availability of MR imaging and the constantly improving technology make it the imaging modality of choice for the patients with a musculoskeletal trauma. This review discusses the role and applications of MR imaging for musculoskeletal trauma. It covers traumatic conditions of the musculoskeletal system, including hemarthrosis, lipohemarthrosis, stress fracture, occult fractures, cartilage injuries, the muscle and tendon trauma, avulsion injuries, extensor mechanism injuries, and traumatic conditions of joints.

  17. Cartilage imaging in children: current indications, magnetic resonance imaging techniques, and imaging findings.

    PubMed

    Ho-Fung, Victor M; Jaramillo, Diego

    2013-07-01

    Evaluation of hyaline cartilage in pediatric patients requires in-depth understanding of normal physiologic changes in the developing skeleton. Magnetic resonance (MR) imaging is a powerful tool for morphologic and functional imaging of the cartilage. In this review article, current imaging indications for cartilage evaluation pertinent to the pediatric population are described. In particular, novel surgical techniques for cartilage repair and MR classification of cartilage injuries are summarized. The authors also provide a review of the normal anatomy and a concise description of the advances in quantitative cartilage imaging (ie, T2 mapping, delayed gadolinium-enhanced MR imaging of cartilage, and T1rho). Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Magnetic resonance acoustic radiation force imaging.

    PubMed

    McDannold, Nathan; Maier, Stephan E

    2008-08-01

    Acoustic radiation force impulse imaging is an elastography method developed for ultrasound imaging that maps displacements produced by focused ultrasound pulses systematically applied to different locations. The resulting images are "stiffness weighted" and yield information about local mechanical tissue properties. Here, the feasibility of magnetic resonance acoustic radiation force imaging (MR-ARFI) was tested. Quasistatic MR elastography was used to measure focal displacements using a one-dimensional MRI pulse sequence. A 1.63 or 1.5 MHz transducer supplied ultrasound pulses which were triggered by the magnetic resonance imaging hardware to occur before a displacement-encoding gradient. Displacements in and around the focus were mapped in a tissue-mimicking phantom and in an ex vivo bovine kidney. They were readily observed and increased linearly with acoustic power in the phantom (R2=0.99). At higher acoustic power levels, the displacement substantially increased and was associated with irreversible changes in the phantom. At these levels, transverse displacement components could also be detected. Displacements in the kidney were also observed and increased after thermal ablation. While the measurements need validation, the authors have demonstrated the feasibility of detecting small displacements induced by low-power ultrasound pulses using an efficient magnetic resonance imaging pulse sequence that is compatible with tracking of a dynamically steered ultrasound focal spot, and that the displacement increases wi