A Three-Dimensional Deep Convolutional Neural Network for Automatic Segmentation and Diameter Measurement of Type B Aortic Dissection

Objective@#To provide an automatic method for segmentation and diameter measurement of type B aortic dissection (TBAD). @*Materials and Methods@#Aortic computed tomography angiographic images from 139 patients with TBAD were consecutively collected. We implemented a deep learning method based on a three-dimensional (3D) deep convolutional neural (CNN) network, which realizes automatic segmentation and measurement of the entire aorta (EA), true lumen (TL), and false lumen (FL). The accuracy, stability, and measurement time were compared between deep learning and manual methods. The intra- and inter-observer reproducibility of the manual method was also evaluated. @*Results@#The mean dice coefficient scores were 0.958, 0.961, and 0.932 for EA, TL, and FL, respectively. There was a linear relationship between the reference standard and measurement by the manual and deep learning method (r = 0.964 and 0.991, respectively). The average measurement error of the deep learning method was less than that of the manual method (EA, 1.64% vs. 4.13%; TL, 2.46% vs. 11.67%; FL, 2.50% vs. 8.02%). Bland-Altman plots revealed that the deviations of the diameters between the deep learning method and the reference standard were -0.042 mm (-3.412 to 3.330 mm), -0.376 mm (-3.328 to 2.577 mm), and 0.026 mm (-3.040 to 3.092 mm) for EA, TL, and FL, respectively. For the manual method, the corresponding deviations were -0.166 mm (-1.419 to 1.086 mm), -0.050 mm (-0.970 to 1.070 mm), and -0.085 mm (-1.010 to 0.084 mm). Intra- and inter-observer differences were found in measurements with the manual method, but not with the deep learning method. The measurement time with the deep learning method was markedly shorter than with the manual method (21.7 ± 1.1 vs. 82.5 ± 16.1 minutes, p < 0.001). @*Conclusion@#The performance of efficient segmentation and diameter measurement of TBADs based on the 3D deep CNN was both accurate and stable. This method is promising for evaluating aortic morphology automatically and alleviating the workload of radiologists in the near future.

The reproducibility of left ventricular strain measured by CT and its agreement with speckle tracking echocardiography / 中华放射学杂志

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.

A study of simple congenital coronary artery anomalies based on a large-sample coronary CT angiography / 中华放射学杂志

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.

Latent classes of resilience and their stress difference of medical students / 中国实用护理杂志

Objective@#To explore the classification characteristics of medical students resilience, and psychological stress difference of each latent class.@*Methods@#A total of 500 medical students from a medical university majoring in five-year clinical in Liaoning province were investigated by using the general questionnaire, the resilience scale and the Chinese college students stress scale.@*Results@#Three latent classes model of resilience in medical students was supported, including "low tenacity group" (32.7%), "general resilience group" (32.1%) and "tenacity-strength group" (35.2%). In Logistic regression analysis, the proportion of students whose majors met their interests in the general resilience group (OR=3.796) and the tenacity-strength group (OR=7.556) was larger. There were significant differences in psychological stress scores between different latent classes (P<0.01).@*Conclusions@#Medical students′ resilience has obvious classification characteristics, and there were different distributions in different latent classes of whose majors meet their interests. Researchers and teachers should pay more attention to the students who have less resilience and whose majors are not in accordance with their own interests, develop their professional interest, and improve psychological stress through appropriate intervention methods.

Analysis of risk factors related to death in type A aortic intramural hematoma with conservative therapy / 中华放射学杂志

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.

Latent classes of resilience and their stress difference of medical students / 中国实用护理杂志

Objective:To explore the classification characteristics of medical students resilience, and psychological stress difference of each latent class.Methods:A total of 500 medical students from a medical university majoring in five-year clinical in Liaoning province were investigated by using the general questionnaire, the resilience scale and the Chinese college students stress scale.Results:Three latent classes model of resilience in medical students was supported, including "low tenacity group" (32.7%), "general resilience group" (32.1%) and "tenacity-strength group" (35.2%). In Logistic regression analysis, the proportion of students whose majors met their interests in the general resilience group ( OR=3.796) and the tenacity-strength group ( OR=7.556) was larger. There were significant differences in psychological stress scores between different latent classes ( P<0.01). Conclusions:Medical students′ resilience has obvious classification characteristics, and there were different distributions in different latent classes of whose majors meet their interests. Researchers and teachers should pay more attention to the students who have less resilience and whose majors are not in accordance with their own interests, develop their professional interest, and improve psychological stress through appropriate intervention methods.

Feasibility study on iodine flow rate injection protocol to achieve consistent image quality in coronary CT angiography / 中华放射学杂志

Objective To investigate the feasibility of using a specific iodine delivery rate in coronary computed tomography angiography(CCTA) to obtain high and uniform image quality in patients with different body weight, according to the latest guideline of contrast medium injection protocol. Methods A total of 159 consecutive patients who had undergone CCTA for ruling out coronary heart disease were prospectively enrolled and divided into five subgroups according to body weight: ≤60, 60-70, 70-80, 80-90,>90 kg, the former three subgroups were scanned using 100 kV tube voltage, the latter two subgroups were scanned using 120 kV tube voltage. All patients were injected with the contrast agent of which concentration was 370 mgI/ml, using a specific iodine delivery rate (1.0, 1.2, 1.4, 2.0 and 2.2 mgI/s, respectively). The Shapiro?Wilk test was performed to assess the normality of data distribution, including the CT attenuations in the aortic root, proximal left anterior descending artery, the distal segments of the right coronary artery, signal?to?noise ratio (SNR), contrast?to?noise ratio (CNR) and subjective image quality scores. Parameters accorded with normal distribution were compared by analysis of variance (ANOVA). Results There were no statistical differences in the CT attenuations (HU) of the aortic root (368.7±32.4, 356.7±30.8, 366.0±34.6, 360.7±25.0, 352.3±28.4, respectively, F=1.541, P=0.19); This was also true for the proximal segments of the left anterior descending arteries and the distal segments of right coronary arteries (all P>0.05). Also, there were no statistical differences of SD, CNR and SNR in neither the proximal part of the left anterior descending coronary arteries nor the distal right coronary arteries in these five groups (all P>0.05); There were no statistical differences in subjective scores of each group (3.91±0.23, 3.83±0.30, 3.94± 0.21, 3.90±0.27, 3.95±0.20, respectively, F=1.202, P=0.36). Conclusion For patients undergoing CCTA with different body weights, using guideline introduced iodine delivery rate injection protocol of contrast medium could achieve consistent vascular enhancement with satisfied image quality. This protocol is promising to make personalized and standardized CCTA possibly.

Application of low tube voltage combined with low iodine load iso?osmolar contrast in CT angiography for thanscatheter aortic valve replacement planning / 中华放射学杂志

Objective To investigate the feasibility, image quality, and safety of low?tube?voltage, low iodine load iso?osmolar contrast comprehensive cardiac and aortoiliac CT angiography (CTA) for transcatheter aortic valve replacement (TAVR) planning. Methods Ninety?eight consecutive TAVR candidates prospectively underwent combined contrast?enhanced CTA of the aortic root complex and vascular access route. Patients were assigned to group A (2nd generation dual?source CT, 100 kV, contrast 270 mgI/ml iodixanol) or group B (2nd generation dual?source CT, 120 kV, contrast 370 mgI/ml). Mean vascular attenuation, noise, signal?to?noise ratio (SNR), and contrast?to?noise ratio (CNR) of aorta including aortic root, aortic arch, descending aorta at level of diaphragm, abdominal aorta at level of renal artery and femoral artery were compared. Patient creatinine levels before the examination of CTA and during follow?up (24—48 h) were measured. Results The image quality score of aortic root and whole aorta was (4.2±0.7) and (4.3±0.4) respectively in experimental group, (4.3±0.6) and (4.3±0.3) in control group. No significant difference in subjective image quality score between two groups including aortic root image and whole aorta image (t=-0.130,-0.155,P=0.694, 0.822). The image noise of aortic root and femoral artery were higher in experimental group than that in control group (P<0.05). Radiation dose in experimental group was higher than that in control group [(6.1 ± 0.4) vs. (8.0 ± 0.4) mSv, t=-9.253, P=0.001]. There were no significant changes in creatinine levels among groups during the follow?up. Conclusion TAVR candidates can be safely and effectively evaluated by a comprehensive CTA protocol with low iodine load iso?osmolar contrast using low?tube?voltage acquisition.

Comparison of aortic valve dysfunction and ascending aorta dimension between patients with different bicuspid aortic valve morphology / 中华心血管病杂志

Objective@#To compare the characteristics of aortic valve dysfunction and ascending aorta dimension in patients with different bicuspid aortic valve (BAV) morphology.@*Methods@#A total of 197 patients who underwent aortic valve replacement between April 2014 and March 2015 and were diagnosed with BAV by pathology were included, and their clinical data were retrospectively analyzed. Patients were divided into raphe+ group(109 cases) and raphe- group(88 cases) according to the presence or absence of raphe, and L-R group(fusion of left and right cusp, 125 cases) and L/R-N group(fusion of left or right and noncoronary cusp, 72 cases) according to fusion type of the cusps. The characteristics of aortic valve dysfunction and ascending aorta dimension in patients with different BAV morphology were compared.@*Results@#(1) Aortic stenosis incidence was lower in raphe+ group than in raphe- group(22.9%(25/109) vs. 69.3%(61/88), P<0.001). Aortic regurgitation incidence was higher in raphe+ group than in raphe- group (61.5%(67/109) vs. 22.7%(20/88), P<0.001). Incidence of type 1 of aortic root dilation was higher in raphe+ group than in raphe- group (23.9%(26/109)vs.10.2%(9/88), P=0.024). (2) Aortic stenosis incidence was lower in L-R group than in L/R-N group(29.6%(37/125) vs. 68.1%(49/72), P<0.001). Aortic regurgitation incidence was higher in L-R group than in L/R-N group (59.2%(74/125) vs. 18.1%(13/72), P<0.001). Incidence of type 3 of aortic root dilation was lower in L-R group than in L/R-N group(10.4%(13/125) vs. 37.5%(27/72), P=0.006). (3) Aortic stenosis incidence was lower in L-R patients than in L/R-N patients(15.1%(13/86)vs. 52.2%(12/23), P=0.001), and aortic regurgitation incidence was higher in L-R patients than in L/R-N patients in raphe+ group(73.3%(63/86)vs. 17.4%(4/23), P<0.001).@*Conclusion@#There is significant difference in the type of valvular dysfunction and ascending aorta dilatation in patients with different morphological characteristics of BAV.