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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 explore current status of scanning protocol and radiation dose of coronary CT angiography (CCTA) in China from 2017 to 2018.Methods:Cluster sampling was conducted according to the number and distribution of tertiary and secondary hospitals in provinces across the country, and 75 hospitals (30 secondary hospitals and 45 tertiary hospitals) were finally included. The patients who underwent CCTA from October 2017 to May 2018 were systematically sampled, and 1 312 patients were finally included. Patients were divided into two groups according to the level of hospital. Basic clinical characteristics were collected, including age, sex, height, weight, CT scanning equipment, scanning parameters, scanning model, post-processing scheme and radiation dose. Wilcoxon rank sum test, χ 2 tes were used in statistical analysis. Radiation dose was compared between different tube voltage, scanning model and post-processing solutions groups. Results:The ratio of employing low tube voltage (≤100 kV) was 35.4% (464/1 312). The rate of using low tube voltage in different weight groups (<60, 60-90,>90 kg) were 45.0%(126/280), 39.6%(256/647), 33.3%(8/24) in tertiary hospitals respectively, and 27.8%(25/90), 18.5%(49/265), 0(0/6) in secondary hospitals respectively. The rate of using low tube voltage in different weight groups (<60, 60-90,>90 kg) was significantly higher in tertiary hospitals than in secondary hospitals (χ2=34.25, 51.05, 207.05, P<0.001). Prospective electrocardiogram triggering model was used in 38.5% (505/1 312) of the patients. Application rate of iterative reconstruction was 82.5% (1 082/1 312). Among the patients who applied iterative reconstruction, tube voltage of 120 kV and above was used in 58.8% (636/1 082) of the patients. The effective radiation dose (ED) of CCTA was 11.84 (6.33, 16.66) mSv. The ED of CCTA examination in tertiary hospitals was slightly lower than that of secondary hospitals ( Z=-5.73, P<0.001). The ED of CCTA examination using prospective electrocardiogram triggering model was lower than that of retrospective electrocardiogram triggering model ( Z=-15.76, P<0.001). The ED of CCTA examination with iterative reconstruction [11.76 (6.94, 17.58) mSv] was slightly lower than those without iterative reconstruction ( Z=-3.45, P=0.004). Conclusions:The problems were focused on tube voltage fixation, low application proportion of low tube voltage and prospective electrocardiogram triggered protocol, and nonstandard application of iterative reconstruction technology during CCTA examination in the investigated hospitals. The nonstandard scanning protocol was an important causation of high ED in CCTA examination. Although the scanning standardization degree of tertiary hospitals was higher than that of secondary hospitals, but it still did not meet the guidelines.
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Objective:To investigate the impact on image quality of a new deep learning image reconstruction (DLIR) algorithm in dynamic CT myocardial perfusion imaging (CTP) and to explore whether the algorithm affects the quantification of myocardial blood flow (MBF) in swine.Methods:Dynamic CTP imaging was performed in five anesthetized domestic swine [body weight (58.6±1.9) kg], at both rest and stress state. The tube voltages were fixed at 100 kV, and the low-dose and high-dose scanning tube currents were set as 150 mA and 300 mA, respectively. The low-dose (LD) scan data were reconstructed with filtered back projection (FBP) and three different DLIR strengths (low, medium, and high). High-dose (HD) scan data were reconstructed with filtered back projection (FBP) only. Subjective (5-point scale) image quality was evaluated, and objective evaluations included image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) was performed. Linear regression was used to test the linear trend between DLIR algorithm strength and image quality. Data sets normality was determined by the Shapiro-Wilk test. Comparisons between groups were performed using Student′s t test for normally distributed data or the Wilcoxon rank-sum test for non-normally distributed data. Results:The mean effective radiation dose was 7.2 and 3.8 mSv for the HD protocol and the LD protocol, respectively, with statistically significant difference found between two protocols ( t=282.50, P<0.001). The image noise of the images obtained at LD protocol gradually decreased and the image SNR and CNR gradually increased with DLIR algorithm strength increased ( F=60.10,35.87,41.41; P for trend were all<0.001). As for DLIR-high strength (LD) and FBP (HD) images, the image noise values were (31.7±3.1) and (38.2±1.2) HU; SNR were 16.6±2.0 and 13.8±0.8; CNR were 14.5±1.7, 11.6±0.9, respectively, with significant differences found between two groups ( t=5.70, 4.15, 5.68; all P<0.05). The subjective scores of DLIR-high strength (LD) and FBP (HD) images were significantly different (4.8±0.4 and 4.2±0.6, Z=2.12, P<0.05). No significant differences were found between the MBF calculated from FBP (LD) and from DLIR-high strength (LD), with the values as (81.3±17.3) ml·100 ml -1·min -1 vs. (79.9±18.3)ml·100 ml -1·min -1 at rest state; and (99.4±24.9)ml·100 ml -1·min -1 vs. (100.7±27.3) ml·100 ml -1·min -1 at stress state ( t=1.10, 0.89; P>0.05). Conclusion:DLIR-high strength can improve image quality of myocardial CTP in swine, and can reduce radiation dose without influencing the MBF calculation.
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Objective:To investigate the reproducibility of left ventricular strain assessed by CT feature tracking(CT-FT) and its correlation and agreement with speckle tracking echocardiography (STE).Methods:Thirty outpatients with suspected coronary heart disease who underwent whole cardiac cycle coronary CTA and transthoracic echocardiography within one week were prospectively enrolled in November 2019. Left ventricular volume and strain parameters were measured by CT-FT and STE, including left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), global longitudinal strain(GLS), global radial strain (GRS),and global circumferential strain(GCS). GLS included endocardial global longitudinal strain (EndoGLS) and myocardial global longitudinal strain (MyoGLS), GCS included endocardial global circumferential strain (EndoGCS) and myocardial global circumferential strain (MyoGCS). ICC was used to evaluate intra-and inter-observer differences in strain measured by CT-FT. The differences of measurements between CT-FT and STE were compared by paired-samples t test. Pearson correlation coefficient was used to analyze the correlation between CT-FT and STE measurements. Agreement between measurements of two modalities was assessed by Bland-Altman analysis. Results:There was a good consistency in EDV, ESV, EF, EndoGLS, MyoGLS, GRS, EndoGCS and MyoGCS measured by CT-FT between intra-and inter-observer (ICC was 0.775-0.964, P<0.001). There was no significant difference in EF measured by CT-FT and STE [(60.27±8.70) % and (61.22±5.64) %, P=0.443]. EndoGLS, MyoGLS, GRS and MyoGCS measured by CT-FT were (-20.47±4.01)%, (-18.06±3.75)%, (73.90±20.58) % and (-18.48±3.65)%, respectively, while the strain measured by STE were (-18.97±3.33)%, (-16.49±2.60)%, (18.56±3.06)% and (-20.26±4.45)%, respectively. The differences were statistically significant between CT-FT and STE ( t=-2.367, -2.945, 12.161, 2.459, P<0.05). The EndoGCS measured by CT-FT and STE were (-27.78±6.66)% and (-29.18±7.24)%, respectively, with no statistical significance ( P=0.223).The correlation coefficients of EndoGLS, MyoGLS, GRS, EndoGCS and MyoGCS measured by CT-FT and STE were 0.566, 0.629, 0.509, 0.606 and 0.539, respectively ( P<0.05). The average difference of EndoGLS, MyoGLS, GRS, EndoGCS and MyoGCS measured by CT-FT and STE was -1.5%, -1.6%, 55.3%, 1.4% and 1.8%, respectively, with 95% limits of agreement was -8.3%-5.3%, -7.3%-4.2%, 18.1%-92.5%, -10.7%-13.6% and -6.0%-9.5%, respectively. Conclusions:The left ventricular global strain evaluated by CT-FT was feasible, and the agreement of global strain between CT-FT and STE was good but not interchangeable. CT can be an alternative method for "one-stop" evaluation of cardiac anatomy and function in patients with poor echogenic windows and contraindications for MRI.
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Objective:To investigate the classification and prevalence of simple congenital coronary artery anomalies (CCAA) in Chinese in a large samples of coronary CT angiography (CCTA), and briefly summarize the CT characteristics of "malignant" anomalies.Methods:The data of patients who had undergone CCTA from July 2009 to January 2017 and were diagnosed as simple CCAA were analyzed retrospectively. CCAA were classified according to the origination, number of orifices and termination, and the prevalence of various CCAA was statistically analyzed. Anomalous origin of coronary artery included the origin of coronary artery from the opposite coronary sinus, the non-coronary sinus, the aorta or around the primary sinus, the pulmonary artery, and left circumflex artery originated from the diagonal branch. Abnormal number of orifices included single coronary artery (SCA), right coronary artery and conus branch arising separately, and left anterior descending branch and circumflex branch arising separately. Abnormal termination was coronary artery fistula (CAF). Anomalous origin of coronary artery from the opposite sinus, anomalous origin of the coronary artery from the pulmonary artery, SCA, and multiple or large CAFs were defined as"malignant"anomalies.Results:Among 165 133 patients, 2 148(1.301%) had coronary anomalies, including 1 302 (0.789%) of origin anomalies, 298 (0.181%) of abnormal number of orifices and 548 (0.332%) of abnormal termination. There were 700 cases (0.424%) with coronary artery rising from the opposite sinus, 179 of which had opening or proximal lumen stenosis due to compression, 7 of which had subendocardial myocardial ischemia or infarction on CCTA without coronary artery disease (CAD). The coronary arteries originated from posterior sinus, the aorta or around the primary sinus were found in 48 cases (0.029%), 531 cases(0.322%), respectively. Coronary artery originating from pulmonary artery was detected in 20 cases (0.012%), all of which were left main trunk originating from pulmonary artery, showed tortuous dilation of coronary arteries. Five cases showed obvious subendocardial myocardial ischemia or infarction without CAD. SCA, right coronary artery and conus branch arising separately, left anterior descending branch and circumflex artery arising separately were detected in 102 (0.062%), 53 (0.032%) and 143 (0.087%) cases respectively. Only 1 of 102 cases with SCA showed myocardial ischemia without CAD. A total of 548 cases (0.332%) were diagnosed as CAF, of which the coronary-pulmonary fistula was most common with a highest prevalence of 0.277% (458 cases). Coronary artery-atrial fistula and coronary artery-ventricular fistula were detected in 22 (0.013%) and 60 (0.036%) cases. There were 6 cases (0.004%) of coronary artery-coronary venous fistula and 2 cases (0.001%) of coronary artery-superior vena cava fistula.Conclusions:The occurrence of CCAA is not uncommon, among which anomalous origin of coronary artery is the most common, and special attention should be paid to "malignant"anomalies.
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Objective:To explore the quantitative characteristics and vulnerable features on coronary CT angiography (CCTA) of coronary atherosclerotic plaques according to age-based classification.Methods:A total of 2 660 consecutive out-patient patients after screening for exclusion criteria were enrolled in a single-center prospective cohort study from January to December of 2017 in Fuwai Hospital. They were all suspected with coronary heart disease and referred for CCTA examinations. There were 5 078 main branches of coronary artery with atherosclerosis plaque. 2 660 patients and 5 078 branches were individually divided into five groups according to their age: ≤40, 41-50, 51-60, 61-70, >70-year-old group. The plaque burden and volume percentage of fibrous, lipid and calcified components of plaques were measured, as well as the incidence of CT vulnerable signs. Chi-square test and rank sum test were used to compare the differences of baseline data and the distribution characteristics of the above imaging parameters in different age groups. The correlation between routine risk factors of coronary heart disease and vulnerable plaque of CT was also analyzed by logistic regression.Results:The characteristics of each plaque component of age-based groups were different. The main component of coronary plaques in all age groups was fibrous and the proportion was 83.33% (75.42%, 91.60%), 81.51% (74.44%, 89.07%), 81.85% (74.88%, 88.88%), 82.33% (74.03%, 89.20%),80.99% (73.43%, 88.19%) (χ 2=9.775, P=0.044) respectively. The calcification volume percentage of plaque increased significantly with aging: 1.10% (0, 5.53%),1.19% (0, 7.58%), 2.29% (0, 10.45%), 3.97% (0, 14.25%), 6.84% (0.40%, 17.55%) (χ 2=146.719, P<0.001); the lipid volume percentage first increased and then decreased with aging, and the value was highest in 40-50-year-old group: 10.94% (5.71%, 19.31%), 12.18% (5.81%, 19.56%), 10.48% (4.83%, 17.14%), 8.14% (3.23%, 15.11%), 7.20% (2.44%, 13.68%) (χ 2=137.470, P<0.001).The results of CT vulnerable characteristics of plaques showed that the incidence of positive remodeling and low-attenuation plaque sign and also the percentage of vulnerable plaque identified by CT all first increased and then decreased, also reached the maximum at 41-50 years old (73.9%, 91.9%, 73.4%) (χ 2=8.678, 3.970, 21.577; P=0.07, P<0.001, P<0.001). Age and sex (male) were independent risk factors for vulnerable plaques identified by CT according to logistic regression analysis. The proportion of CT vulnerable plaques decreased with age (regression coefficient was-0.08). However, the percentage of CT vulnerable plaque in male was higher than that in female patients (regression coefficient was 0.188). Conclusions:The plaque burden increased with age. The lipid volume percentage and incidence of vulnerable plaques identified by CT both increased firstly and then decreased with the highest values in 40-50-year-old group.
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Objective:To explore risk factors of death in type A intramural hematoma (IMH) patients with conservative therapy and provide important information for clinical risks stratification and decisions-making.Methods:This retrospectively study enrolled 130 patients diagnosed with type A IMH in the first CT examination at Fuwai Hospital of Chinese Academy of Medical Sciences and only received conservative therapy between September 2009 and June 2018. Baseline clinical and CT characteristics were recorded. All patients enrolled were followed up. The endpoint was aortic disease-related death, patients were divided into endpoint group and non-endpoint group according to whether or not an endpoint event occurs. Difference between two groups of normally distributed continuous variables, non-normally distributed continuous variables and categorical variables were tested by independent sample t test, Mann-Whitney U test and chi-square test or Fisher′s exact test, respectively. Independent risk factors related to outcomes were assessed with Cox regression analysis and survival analysis. Results:In baseline CT data, the mean value of the maximum aortic diameter (MAD) was (49.2±6.9) mm, and the median value of the maximum hematoma thickness (MTH) was 11.0 (8.5, 13.2) mm. There were 56 and 30 patients with ulcer-like projection (ULP) and intramural blood pool (IBP), respectively, which including 36 patients with ULP of ascending aorta, 51 patients with pericardial effusion and 50 patients with pleural effusion. During a median follow-up time of 1 050 (242, 1 949) days, 26 patients experienced aortic disease-related death. Compared with non-endpoint group patients, patients who experienced aortic disease-related death showed older age and larger MAD( t=2.363, 3.640, P=0.020,<0.001), higher proportion of aortic atherosclerosis, ULP and pericardial effusion (χ 2=5.275, 6.596, 9.325, P=0.022, 0.010, 0.002).In Cox regression multivariate analysis shows that aortic atherosclerosis [hazard ratio (HR)=3.48, P=0.043], ULP (HR=2.66, P=0.019) and pericardial effusion (HR=2.49, P=0.030) were independent risk factors for aortic disease-related death. Conclusions:Aortic atherosclerosis, ULP and pericardial effusion are independent predictors of subsequent aortic disease-related death for type A IMH patients with conservative therapy, identifying these risk factors is helpful for further risk stratification and decisions-making.