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Contrast-enhanced MR angiography utilizing parallel acquisition techniques in renal artery stenosis detection
Slanina, Martin ; Žižka, Jan (advisor) ; Vymazal, Josef (referee) ; Ferda, Jiří (referee)
Contrast-enhanced MR angiography utilizing parallel acquisition techniques in renal artery stenosis detection Objective: The aim of our study was to assess the diagnostic value of contrast- enhanced MR angiography (MRA) utilizing parallel acquisition techniques in the detection of renal artery stenosis (RAS). Material and Methods: 81 hypertensive subjects with suspected RAS were examined on a 1.5 T MR system with body array coil. Bolus tracking was used to monitor the arrival of contrast agent to the abdominal aorta. The MRA sequence parameters were as follows: TR 3.7 ms; TE 1.2 ms; flip angle 25ř; acquisition time 18 s; voxel size 1.1 mm × 1.0 mm × 1.1 mm; centric k-space sampling; parallel acquisition techniques with acceleration factor of 2 (GRAPPA). Renal artery stenosis of 60% and more was considered hemodynamically significant. The results of MRA were compared to digital subtraction angiography serving as a standard of reference. Results: Sensitivity, specificity, positive predictive value and negative predictive value of MRA in the detection of hemodynamically significant RAS were 91%, 96%, 94% and 94%, respectively. Prevalence of RAS was 41% in our study population. Conclusion: Contrast-enhanced MRA with high spatial resolution offers sufficient sensitivity and specificity for screening of...
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Coronary atherosclerosis imaging using CT coronary angiography in patients with high risk of coronary heart disease
Baxa, Jan ; Ferda, Jiří (advisor) ; Vymazal, Josef (referee) ; Mechl, Marek (referee)
Coronary atherosclerosis imaging using CT coronary angiography in patients with high risk of coronary heart disease Coronary heart disease (CHD) belongs to most frequent disorders and in industrial countries is responsible for most deaths in population. The costs of treatment of the clinical manifested CHD are high, so there is tendency to detect this disease in early phase and ideally before development of clinical symptoms. Aim of our study was to evaluate the value of coronary CT angiography (CCTA) in detecting of coronary atherosclerosis in early (preclinical) phase. Our goals were estimation of prevalence of atherosclerosis in group, influence of main risk factors on grade and character of atherosclerotic changes. In follow-up we concerned on occurrence of cardiac events. 205 patients with increased cardiovascular risk underwent CCTA using dual-source CT. Coronary findings were analyzed by character of atherosclerotic changes and degree of event. stenosis. Statistical evaluation of influence of risk factors was made using the odds ratio. The statistically important differences were tested between subgroup of type 2 diabetics and non-diabetics. All patients were under follow-up for two years. Overall prevalence of atherosclerosis in analyzed group was 73 %, calcified lesions were found in 63.9 %...
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