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Objective:To explore the impact of coronary CT angiography (CCTA) image quality and related factors on the diagnostic performance of CT-derived fractional flow reserve (CT-FFR).Methods:Based on the CT-FFR CHINA trial, the prospective multicenter trial enrolled patients with suspected coronary artery disease who underwent CCTA, CT-FFR and FFR measurement. The subjective and objective assessments of CCTA image were performed on a per-vessel level. The objective assessments included the enhancement degree of coronary artery, the signal-to-noise ratio (SNR) of the aortic root. We used χ 2 test and DeLong test to compare the diagnostic performance of CT-FFR with FFR as the reference standard in different subjective groups (non-artifact vs. artifact), enhancement degree of coronary artery groups (≤400 vs. 401-500 vs.>500 HU), SNR of the aortic root groups (≤16.9 vs.>16.9), body mass index (BMI) groups (<25 kg/m 2 vs.≥25 kg/m 2) and heart rate groups (<75 bpm vs.≥75 bpm). FFR and CT-FFR values≤0.80 was identified as myocardial ischemia. Results:The study enrolled 317 patients with 366 vessels. All target vessels in CCTA images were successfully analyzed by CT-FFR. The accuracy, sensitivity, specificity, positive predictive value, negative predictive value and AUC of the non-artifact group were 90.45%, 86.75%, 93.10%, 90.00%, 90.76% and 0.928, respectively, and those of the artifact group were 83.23%, 87.21%, 79.01%, 81.52%, 85.33% and 0.869, respectively. The differences in accuracy and specificity were statistically significant (χ 2=4.23, P=0.040; χ 2=8.55, P=0.003). The diagnostic efficacy of CT-FFR had no statistically significant differences among different objective groups (all P>0.05). Conclusions:The artifact of CCTA image has an effect on CT-FFR in the diagnosis of myocardial ischemia. The degree of vascular enhancement, SNR, BMI, and heart rate have no significant effect on the diagnostic performance of CT-FFR.
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Objective:To probe the diagnostic performance of the combined evaluation of stenosis and plaque characteristics based on coronary computed tomography angiography (CCTA) in identification of myocardial ischemic lesions, using the invasive coronary angiography (ICA)-based fractional flow reserve (FFR) as the gold standard.Methods:From November 2018 to March 2020, the patients with suspected or known coronary artery disease and scheduled for ICA at 5 clinical trials centers were enrolled in this study. All the patients underwent CCTA, ICA and FFR in turn in one week. The luminal stenosis and plaque characteristics were measured and assessed including plaque burden, volume ratios of calcification and non-calcification, lesion length and CT vulnerable features. All culprit vessels were divided into FFR≤0.8 and FFR>0.8 groups, and the parameters of plaque characteristics were compared. The correlation of ischemic lesions with CCTA stenosis and plaque characteristics was analyzed by the logistic regression analysis. The ROC curve was used to evaluate the sensitivity and specificity of CCTA stenosis rate and plaque characteristics, meanwhile the area under curve (AUC) of each parameter was compared by Delong test.Results:Three hundred and sixty-six culprit vessels in 317 patients were analyzed in this study (169 vessels in ischemia group and 197 in nonischemia group). The plaque burden [34.3% (30.3%, 38.8%) vs. 32.4% (28.5%, 37.9%); Z=-2.622, P=0.009], proportion of CT vulnerable features [26.9% (45/169) vs.11.7% (23/197); χ 2=15.311, P<0.001] and lesion length [22.1 (14.4, 35.0) mm vs. 17.6 (11.0, 26.0) mm; Z=-4.388, P<0.001] in FFR≤0.8 group were higher than those in FFR>0.8 group. The results of logistic regression analysis revealed that CCTA stenosis, lesion length, and CT vulnerable features were significant predictors for myocardial ischemia (OR values: 3.794, 2.461, 1.027; P<0.001, P=0.002, P=0.002). The diagnostic performance of CCTA ≥50% stenosis alone in identification of ischemic lesions was low (AUC=0.625). When it combined high-risk plaque characteristics and lesion length, the AUC was improved to 0.714 with a statistical significance. Conclusions:CCTA stenosis, lesion length, and CT vulnerable features are major predictors in identification of myocardial ischemic lesions, and the combination will significantly improve the diagnostic performance of CCTA ≥50% stenosis.
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Objective To study the role of pulmonary angiography with 16-detector row spiral CT in the diagnosis of pulmonary embolism (PE).Methods Forty-nine patients suspected of having pulmonary embolism were examined prospectively with 16-detector row spiral CT pulmonary angiography.Contrast enhanced 3-mm section thickness was used to scan the entire chest and the raw data were used to perform the reconstruction with 1-mm section thickness and multiplanar reformation (MPR).The axial images of 3-mm,1-mm section thickness,and MPR were compared.Results PE were diagnosed in 42 of 49 patients,and 352 branches were detected,including 8 left or right main pulmonary arteries,96 lobar arteries,132 segmental vessels,and 116 subsegmental arteries.For displaying the emboli in main pulmonary arteries and lobar arteries,the results of the images with 3-mm,1-mm section thicknesses and MPR were identical.But 1-mm-thick section yielded higher rate of detecting emboli in segmental and subsegmental pulmonary arteries compared with 3-mm-thick sections,and there was significant difference statistically (P0.05).Conclusion 16-detector row spiral CT pulmonary angiography is non-invasive,fast,and highly sensitive for PE,and it should be the modality of choice for the diagnosis of PE.
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Objective To explore the value of CT venography (CTV) in diagnosis of cerebral venous sinus thrombosis (CVST) . Methods 16 patients with CVST were examined by CTV. 2D and 3D vascular images were reconstructed through workstation. Results Filling-defect was seen as "empty triangle sign" on the axial image.Multiple CVST were displayed in 11 patients,among them,8 cases involved superior sagittal sinus,3 cases involved lateral sinus. Single CVST was displayed in 5 patients,2 cases involved superior sagittal simes,2 cases involved straight sinus,1 case involved inferior sagittal sinus. The irregular narrowing or occlusion of the sinus and dilation of the branch of vein were observed in all 16 patients on 2D or 3D images. Hydrocephalus, cerebral infarction and cerebral hemorrhage were seen in 11 cases, 6 cases and 4 cases respectively. Conclusion CTV is a sensitive and distinctive technique in diagnosing CVST.