| Part Ⅰ.Optimization of one-stop imaging image quality fordual-source CT coronary angiography and resting-state myocardialperfusionBACKGROUND: Beam hardening artefact(BHA)is one of the common artifacts in CT imaging,which behaves similarly to myocardial ischemia in terms of myocardial perfusion,both of which are striped perfusion defects,thus affecting the judgment of myocardial activity.Noise-optimized virtual monoenergetic imaging(VMI+)reconstruction and iterative beam hardening correction(IBHC)algorithms in dual-source CT are good at optimizing images and mitigating BHA.OBJECTIVE: To investigate the optimal combination of scanning parameters for image quality optimization by VMI+ reconstruction with IBHC algorithm in dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging.METHODS: A retrospective analysis of 44 subjects who underwent 3rd generation Siemens dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging at our hospital between December 2021 and March 2023.The background noise,signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR)and BHA of the selected regions were compared and analyzed using multiple VMI+ reconstructions,VMI+ reconstructions combined with IBHC algorithm and 120 KV mixed energy reconstructed images.RESULTS: Using VMI+ reconstruction to increase the Ke V value can reduce the background noise,improve the SNR and CNR values,and thus improve the overall image quality,and the BHA is cut off at 100 Ke V and reaches the lowest value there.The combined IBHC algorithm reconstruction can significantly improve the background noise and HBA,but has no improvement on SNR and CNR values.Conclusion: In dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging,VMI+ images can reduce myocardial perfusion image noise and improve SNR and CNR values compared with 120 KV mixed energy mode imaging,and VMI+ images combined with IBHC algorithm reconstruction can significantly improve background noise and HBA,but not SNR and CNR values.Part Ⅱ Preliminary study of dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging to measureiodine content in normal human left ventricular myocardiumBackground: Dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging,which can produce two sets of images of coronary computed tomography angiography(CCTA)and myocardial perfusion imaging(MPI)in one scan,is a hot topic of current research.However,the current evaluation of MPI mainly relies on the experience of the reader and lacks objective evaluation criteria;therefore,the quantitative analysis of myocardial iodine values is particularly important for myocardial activity assessment.OBJECTIVE: To investigate the normal values of myocardial iodine content in the left ventricle of normal subjects in dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging and the variation of myocardial iodine between segments.METHODS: Thirty-eight healthy adult subjects undergoing 3rd generation Siemens dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging in our hospital between December 2021 and March 2023 were retrospectively analyzed.According to the American Heart Association’s standard myocardial 17 segmentation method,the iodine content and normalized iodine concentration(NIC)values of the left ventricular myocardium were measured separately in different segments using post-processing software,and the segmental changes in the iodine content and NIC values of the left ventricular myocardium were analyzed.RESULTS:(1)The mean LV myocardial iodine content of enrolled healthy adults was 2.19±0.82 mg/ml and LV myocardial NIC value was 0.13±0.05;the myocardial iodine content of each segment of LV myocardium from 1 to 17 was2.09±0.60,2.50±0.93,2.56±0.97,2.20±0.78,2.41±1.04 2.29±0.87,1.93±0.62,2.44±0.85,2.64±0.79,2.18±0.75,2.30±0.77,2.18±0.84,1.80±0.60,2.06±0.65,2.05±0.56,2.13±0.71,and 1.41±0.68 mg/ml,respectively;NIC values were 0.13±0.04,0.15±0.05,0.15±0.05,0.13±0.05,0.14±0.05,0.14±0.04,0.11±0.03,0.15±0.04,0.16±0.04,0.13±0.05,0.14±0.04,0.13±0.05,0.10± 0.03,0.13±0.04,0.12±0.03,0.13±0.04,and 0.09±0.04.(2)The differences in myocardial iodine content and NIC values between myocardial segments 1-17 were statistically significant(P<0.05 or P<0.001),with segment 17 having the lowest iodine and NIC values.CONCLUSION: The mean myocardial iodine content of the left ventricle in healthy subjects in this study was 2.19 ± 0.82 mg/ml,and the mean NIC value of the left ventricle myocardium was 0.13 ± 0.05,with the apical myocardium having the lowest iodine content and NIC value,with statistically significant differences in iodine content and NIC value between segments(P < 0.05 or P < 0.001).Part Ⅲ Accuracy of dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging for the diagnosisof stenosis due to coronary calcified plaqueBACKGROUND: Coronary computed tomography angiography(CCTA)has become the test of choice for the diagnosis of coronary artery disease(CAD)because of its noninvasive technical operation and its high sensitivity and negative predictive value for the diagnosis of coronary stenosis.However,when extensive calcified plaques are present in coronary arteries,they tend to appear magnified on CCTA images due to the effect of beam sclerosis artifacts(BHA)and flooding artifacts,which can easily overestimate the severity of coronary stenosis and lead to false-positive results.To address the influence of calcified plaque on the determination of coronary stenosis,virtual monoenergetic imaging(VMI)reconstruction with dual-source CT has been shown to be a more effective method.OBJECTIVE: To evaluate the accuracy of CCTA images by VMI reconstruction in dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging for the diagnosis of coronary stenosis due to calcified plaque,using invasive coronary angiography(ICA)as a control.METHODS: We retrospectively analyzed 19 adult subjects with suspected or confirmed coronary artery disease who underwent 3rd generation Siemens dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging at our hospital between December 2021 and March 2023,and who underwent ICA within 1 month before and after.Coronary stenosis ≥50% was judged as positive according to lumen area,and the sensitivity,specificity,positive predictive value,negative predictive value and accuracy of this scan imaging for the diagnosis of coronary stenosis due to calcified plaque by VMI reconstruction with different Ke V values were analyzed using the area under the subject receiving operating characteristic(ROC)analysis area under curve(AUC)as the main performance evaluation index,using ICA as the gold standard.RESULTS: Using ICA as the gold standard:(1)the sensitivity,specificity,positive predictive value,negative predictive value and accuracy of diagnosing coronary artery stenosis at 50 Ke V,70 Ke V,90 Ke V,110 Ke V and 130 Ke V were97%,42%,68.1%,91.7%,72.8%(50 Ke V);97%,61.5%,76.2%,94.10%,and 81.40%(70 Ke V);90.9%,69.2%,78.9%,85.7%,and 81.4%(90 Ke V);90.9%,73.1%,81.1%,86.3%,and 83.1%(110 Ke V)and 84.8%,80.8%,84.8%,80.8%,and 83.1%(130Ke V).(2)The area under the curve(AUC)for diagnosing coronary stenosis due to calcified plaque using subject receiving operating characteristic(ROC)curve analysis was 0.696,0.793,0.801,0.820,and 0.828 for 50 ke V,70 Ke V,90 Ke V,110 Ke V,and 130 Ke V,respectively.CONCLUSION: For patients with CAD characterized by coronary stenosis due to calcified plaque,dual-source CT coronary angiography and resting-state myocardial perfusion one-stop imaging showed reduced coronary calcified plaque induced flooding artifacts and BHA and clearer calcification under VMI reconstruction with higher Ke V,thus improving the accuracy of stenosis determination. |
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