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Objective To explore the feasibility of delineation of the atherosclerotic plaque in carotid artery using compressed sensing three dimensional motion-sensitized driven equilibrium prepared rapid gradient echo (CS-3D MERGE) technique. Methods Twenty-three patients who underwent carotid endarterectomy (CEA) were enrolled prospectively. In all patients, bilateral carotid arteries were scanned by CS-3D MERGE and contrast-enhanced MR angiography (MRA) simultaneously. Image quality of CS-3D MERGE images was scored. Images from the CS-3D MERGE sequence and contrast-enhanced MRA were used to measure the carotid stenosis, which were divided into four groups:normal group, mild stenosis group, moderate stenosis group, and severe stenosis group. The results were compared between the two methods. And images from the CS-3D MERGE sequence were compared with corresponding histology in identifying major plaque components including lipid rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and calcification (CA). Spearman rank correlation coefficient was used to compare the correlation between the CS-3D MERGE sequence and contrast-enhanced MRA in measuring the carotid stenosis. Agreement was tested comparing images from the CS-3D MERGE sequence with corresponding histology in identifying major plaque components including lipid-rich necrotic core, intraplaque hemorrhage, and calcification. Results Twenty-three CEA patients finished bilateral CS-3D MERGE scanning successfully. Image quality was 3.16±0.25. There was an excellent correlation between CS-3D MERGE and MRA in measuring stenosis (r=0.95, P<0.01). The agreement between CS-3D MERGE and histological results for LRNC detection was 76.2% (16/21). It was less sensitive for IPH detection (71.4%, 15/21). CS-3D MERGE identified all CA accurately (100.0%, 21/21). Sensitivity and specificity were 86.6% (13/15) and 50.0% (3/6) for LRNC, 73.3% (11/15) and 66.6% (4/6) for IPH, 100.0% for CA respectively(16/16, 5/5). Conclusion CS-3D MERGE, a single sequence, can be used to quantify carotid stenosis and plaque components conveniently.
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PurposeTo determine the feasibility and accuracy of dual source CT (DSCT) in assessing myocardial delayed-enhancement and left ventricular wall thickness of hypertrophic cardiomyopathy (HCM) in comparison with cardiac magnetic resonance (CMR).Materials and MethodsEighty patients with HCM confirmed by clinical diagnosis were enrolled in the study. DSCT images and CMR images were acquired at the arterial and lag phases. According to 17-segment model provided by American Heart Association, the left ventricular wall thickness and location of delayed-enhancement were verified, and the correlation of these two methods were analyzed in terms of the diagnosis of myocardial delayed enhancement (MDE).Results1360 myocardial segments for 80 patients were assessed. The left ventricular wall thickness determined by DSCT was significantly correlated with MR results (r=0.88,P<0.01). DSCT and MDE showed substantial agreement on per-patient (n=74,Kappa=0.751,P<0.05) and per-segment (n=1238, Kappa=0.746,P<0.01) levels. For dense myocardial delayed enhancement, CT findings were significantly correlated with those of CMR (r=0.89, P<0.01), but CT scan slightly underestimated the lesion scope of fibrosis. Bland-Altman analysis showed that CT and MRI were different in measuring the lesion volume of myocardial delayed enhancement (mean standard deviation was 2.71%).ConclusionThe cardiac CT examination provides comprehensive information in coronary artery and myocardial assessment, and MDE-DSCT is also effective in the diagnosis of myocardial fibrosis in HCM since it can be used in assessing myocardial fibrosis.
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Objective To investigate the feasibility and accuracy of enhanced magnetic resonance pulmonary perfusion imaging(MRPP) in the diagnosis and follow-up of pulmonary embolism(PE). Methods Sixty patients suspected of PE underwent MRPP. Twenty-seven patients also underwent radionuclide perfusion imaging. 22 patients repeated MRPP examination after 3 day to 1 month anticoagulation or thrombolytic therapy. The feasibility and accuracy of MRPP in the diagnosis and follow-up of PE were evaluated according to the transformation rate of signal (TROS), time-signal curve and some parameters of main pulmonary artery(such as peak value of flow,mean flow velocity and flow rate). The t test and rank sum test were used for the statistics. Results MRPP showed a high agreement with radionuclide perfusion imaging. TROS was (2. 86 ± 2. 48 ) vs ( 6. 72 ± 2. 54) ( t = 3. 370, P ＜ 0. 01 ), the peak time was ( 13.98 ±5.60) vs ( 12. 33 ± 3.63 ) s ( t = 3. 930, P ＜ 0. 01 ), the peak value of main pulmonary blood flow was (60.39 ± 15. 17) vs (69.93±13.22) cm/s(t=2.930, P＜0. 01) and mean flow velocity (11.68±5.46) vs ( 13.54 ± 4. 18 ) cm/s ( t = 2. 380, P ＜ 0. 05 ) before and after anticoagulation or thrombolytic therapy. The flow rate per unit was (80. 57 ± 24. 87) vs ( 85.48 ± 11.81 ) ml/s ( t = 0. 86,P ＞ 0. 05 ) . Conclusion MRPP shows a high agreement with radionuclide perfusion imaging and is a useful method for the diagnosis and follow-up of PE.
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The anaerobic threshold (AT) and maximal oxygen uptake (VO_(2max)) are both important physiological foundation of the aerobic capacity for athletes. The purpose of this study was to evaluate the cross-country skiers' aerobic capacity comprehensively and to provide useful information for selecting and training skiers by using the AT and VO_(2max). The results showed that there were significant differences between men's VO_(2max) (4.4L/min, 69.09 ml/kg. min and VO_(2AT) (2.89 L/min) and women's (3.071/min, 55.33 ml/min for VO_(2max) and 2.03 L/min for VO_(2AT), respectively) (p