Magnetic Resonance Imaging of Focal Lesions of Liver and Spleen Using Gradient-Echo Sequences at 1.5 Tesla: A Comparison with Ultrasound and Sequential Computerized Tomography

1989 ◽  
pp. 1-33
Author(s):  
J. Griebel ◽  
C. F. Hess ◽  
B. Kurtz
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Computerized Tomography ◽  
Resonance Imaging ◽  
Gradient Echo ◽  
Focal Lesions

Morphologic correlate of pathologic Q waves as assessed by gradient-echo magnetic resonance imaging

1994 ◽  
Vol 74 (5) ◽  
pp. 430-434 ◽  
Author(s):  
Frank Michael Baer ◽  
Peter Theissen ◽  
Eberhard Voth ◽  
Christian Alfons Schneider ◽  
Harald Schicha ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
Gradient Echo

scholarly journals Early and late results of carotid endarterectomy: retrospective study of 70 operations

2001 ◽  
Vol 119 (6) ◽  
pp. 206-211 ◽  
Author(s):  
Eduardo Toledo de Aguiar ◽  
Alex Lederman ◽  
Celso Higutchi ◽  
Gerd Schreen
Keyword(s):  
Magnetic Resonance Imaging ◽  
Myocardial Infarction ◽  
Magnetic Resonance ◽  
Carotid Endarterectomy ◽  
Carotid Stenosis ◽  
Computerized Tomography ◽  
Late Results ◽  
Resonance Imaging ◽  
Operative Death ◽  
Tomography Scan

CONTEXT: Indications and results of carotid endarterectomy have been defined from clinical multicentric trials like the European Carotid Surgery Trialists, North-American Symptomatic Carotid Endarterectomy Trial and Asymptomatic Carotid Atherosclerosis Study. The patients included in these trials were highly selected, as were the surgeons performing the operations. Clinical practice is different but the same results should be achieved. OBJECTIVE: To study indications, technique, early and late results, and whether carotid endarterectomy has been performed in accordance with standards defined by multicentric trials. DESIGN: Retrospective case report study. SETTING: A tertiary care private hospital. PARTICIPANTS: 57 patients, on whom 70 carotid endarterectomies were performed over a 10-year period. The median age was 66.4 ± 7.8 years; 43 (75.4%) were male, 41 (71.9%) hypertensive, 36 (63.1%) current smokers and 24 (21.0%) had diabetes. Bilateral carotid stenosis was present in 31 (54.3%) patients, peripheral arterial occlusions in 32 (56.1%) and ischemic cardiopathy in 25 (43.1%). All patients had had angiography and 41 (71.9%) had also had a duplex-scan of neck arteries. Cerebral imaging via computerized tomography scan or magnetic resonance imaging was obtained for 36 patients. Patients were followed up over a period of one to 122 months. MAIN MEASUREMENTS: early and late post-operative death, early and late post-operative stroke, and recurrence of atheroma plaque and symptoms relative to carotid stenosis. RESULTS: There was one post-operative death (1.4%) caused by myocardial infarction and two early strokes (2.8%): a total complication rate of 4.2%. After 3 and 5 years, 95.4% and 81.3% of patients respectively were stroke-free and 72.8% and 67.3% were alive. There were four recurrences and two of them related to stroke. Forty-nine (70%) stenoses operated on were symptomatic. Brain infarction was detected in 59.2% of patients who underwent computerized tomography scan or magnetic resonance imaging. CONCLUSIONS: Carotid endarterectomy was done in accordance with international standards. The most frequent cause of late death was myocardial infarction, and recurrences were related to stroke. Patients should be followed up closely.

scholarly journals Meta-analysis of intravoxel incoherent motion magnetic resonance imaging in differentiating focal lesions of the liver

Medicine ◽  
2018 ◽  
Vol 97 (34) ◽  
pp. e12071 ◽  
Author(s):  
Hongzhen Wu ◽  
Yingying Liang ◽  
Xinqing Jiang ◽  
Xinhua Wei ◽  
Yu Liu ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Meta Analysis ◽  
Intravoxel Incoherent Motion ◽  
Resonance Imaging ◽  
Focal Lesions

scholarly journals High-Resolution CMRO2 Mapping in Rat Cortex: A Multiparametric Approach to Calibration of BOLD Image Contrast at 7 Tesla

2000 ◽  
Vol 20 (5) ◽  
pp. 847-860 ◽  
Author(s):  
Ikuhiro Kida ◽  
Richard P. Kennan ◽  
Douglas L. Rothman ◽  
Kevin L. Behar ◽  
Fahmeed Hyder
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Spin Echo ◽  
7 Tesla ◽  
Relaxation Rates ◽  
Resonance Imaging ◽  
Gradient Echo ◽  
Transverse Relaxation ◽  
Physiologic Parameters ◽  
Spin Echo Sequences

The blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) method, which is sensitive to vascular paramagnetic deoxyhemoglobin, is dependent on regional values of cerebral metabolic rate of oxygen utilization (CMRO2), blood flow (CBF), and volume (CBV). Induced changes in deoxyhemoglobin function as an endogenous contrast agent, which in turn affects the transverse relaxation rates of tissue water that can be measured by gradient-echo and spin-echo sequences in BOLD fMRI. The purpose here was to define the quantitative relation between BOLD signal change and underlying physiologic parameters. To this end, magnetic resonance imaging and spectroscopy methods were used to measure CBF, CMRO2, CBV, and relaxation rates (with gradient-echo and spin-echo sequences) at 7 Tesla in rat sensorimotor cortex, where cerebral activity was altered pharmacologically within the autoregulatory range. The changes in tissue transverse relaxation rates were negatively and linearly correlated with changes in CBF, CMRO2, and CBV. The multiparametric measurements revealed that CBF and CMRO2 are the dominant physiologic parameters that modulate the BOLD fMRI signal, where the ratios of (ΔCMRO2/CMRO2)/(ΔCBF/CBF) and (ΔCBV/CBV)/(ΔCBF/CBF) were 0.86 ± 0.02 and 0.03 ± 0.02, respectively. The calibrated BOLD signals (spatial resolution of 48 μL) from gradient-echo and spin-echo sequences were used to predict changes in CMRO2 using measured changes in CBF, CBV, and transverse relaxation rates. The excellent agreement between measured and predicted values for changes in CMRO2 provides experimental support of the current theory of the BOLD phenomenon. In gradient-echo sequences, BOLD contrast is affected by reversible processes such as static inhomogeneities and slow diffusion, whereas in spin-echo sequences these effects are refocused and are mainly altered by extravascular spin diffusion. This study provides steps by which multiparametric MRI measurements can be used to obtain high-spatial resolution CMRO2 maps.

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