Objective To study the manual control respiratory rhythm trigger acquisition (MCRRTA)technology in improving image quality and shortening acquisition time of the low-field MRCP scan.Methods 40 patients underwent MRCP scans using both automatic respiratory rhythm trigger acquisition (ARRTA)and MCRRTA,and the acquisition time and image quality were also ana-lyzed.Results The acquisition time of MRCP using ARRTA and MCRRTA were 675.13 ± 35.89 s and 546.38 ± 30.61 s respec-tively,exhibiting significant differences using the paired sample t-test (t=13.85,P=0.000).In ARRTA group,the scores of the image quality were 4 in 11 cases (11/40,27.5%);3 in 18 cases (18/40,45.0%);2 in 10 cases (10/40,25.0%);and 1 in only 1 case (1/40,2.5%),respectively.In MCRRTA group,the scores of the image quality were 4 in 25 cases (25/40,65.5%);3 in 10 cases (10/40,25.0%);2 in 5 cases (5/40,12.5%);and no case with 1 score (0/40,0%),respectively.The differences in image quality between two groups were statistically significant using the wilcoxon rank sum test (Z=-3.036,P=0.002).Conclusion MCRRTA technology in low-field MRCP scans can improve significantly image quality and shorten examination time.

Because X-ray digital tomosynthesis (DTS) imaging principle is different from that of CT, DTS has better spatial resolution than that of CT in sagittal and coronal planes, and since DTS is reconstructed to generate"layer" images, its power in the aspect of distinguishing 3D tissue structures is superior to that of general X-ray photography, so DTS can provide 3D information for clinical diagnosis; its radiation dose is markedly lower than that of CT. In recent years, DTS has made progress in the application of skeletal system imaging; the research progress and the possible direction of future application of DTS in bone fracture diagnosis, fracture healing estimation, vertebral bone quality assessment and fracture risk prediction, joint dislocation diagnosis, bone erosion evaluation and postoperative arthroplasty assessment were summarized.

Objective To investigate the diagnostic value of digital tomosynthesis in Schatzker classification of tibial plateau fractures.Methods A total of 43 patients with tibial plateau fractures who had underwent injured knee joints coronal tomosynthesis examinations and as well as digital radiography (DR) examinations including anteroposterior and lateral positions before the surgery were selected from January to June 2015.The imaging evaluation was performed by two diagnostic radiologists independently.Each radiologist consecutively performed Schatzker classification of the DR and tomosynthesis images of the knees of each patient.The consistent Schatzker classification results were finally given,while the inconsistent classification results were discussed.Recording the reading results of two methods and comparing the classification results of two methods with the subsequent intra-operative classification results,evaluating their consistency.Results Twenty-eight patients were included with 14 males and 14 females.The age ranged from 25 to 76 years old with an average of 48.5 years.Fifteen patients were excluded due to combined injuries and the low quality of imaging.Schatzker classification of tibial plateau fractures was performed with DR images,19 cases of fracture classification results were consistent with intra-operative classification,and 9 cases were inconsistent.Twenty-six cases of fracture classification results were consistent with intra-operative classification based on tomosynthesis images but 2 cases with inconsistent results.Intra-operative findings for each fracture were used as the gold standard for classification.The accuracy of the Schatzker classification for tibial plateau fractures were 68％ and 93％ in the two imaging techniques with significant difference (x2=5.143,P=0.016),respectively.The classification results of two imaging methods in 2 patients were both inconsistent with intra-operative classification.The fracture severity of 6 patients was underestimated when using DR images for interpretation,while 1 patient had a missed diagnosis of the lateral tibial plateau collapsed fracture.The consistency between the classification results of DR images as well as classification results of tomosynthesis images and intra-operative typing were moderately and highly consistent,respectively (Kappa coefficient were 0.604 and 0.908,respectively).Conclusion Schatzker classification of tibial plateau fractures was performed with DR images,the lateral tibial plateau collapsed fracture and the lateral plateau splitting fracture could be easily missed or misdiagnosed.However,tomosynthesis imaging could provide a higher accuracy.

Infant nutritional status evaluation is a basic experimental skill in the experimental teaching of nutrition and food hygiene. The construction of this virtual simulation experiment can solve the problems of activeness and poor coordination of infants and young children in the actual operation of the experiment. And based on the application of this virtual simulation project, the experimental teaching method of preventive medicine was explored. This experiment adopted online and offline mixed teaching method, which enriches teaching measures and strengthens the standardized process of infant nutritional status evaluation. After 3 semesters of practice from spring 2018 to spring 2020, the proportion of students who achieved excellent grades was 30.09% (34/113), 56.02% (279/498) and 66.79% (1 080/1 617), respectively, which increased significantly year by year ( Ptrend < 0.001). Among all the 2 228 students, 1 983 students (89%) believed that this experimental teaching could better cultivate the ability of autonomous learning. Through the study of virtual simulation experiments, students have improved their subjective initiative, and laid a foundation for the improvement of students' overall quality and the requirements of school elite education.

OBJECTIVE: To investigate the correlation between the stenosis degree of superior mesenteric artery (SMA) and each artery within the scope of aorto-iliac artery in patients with lower extremity atherosclerotic occlusive disease (LEAOD). METHODS: Images of 70 patients who had undergone the aorta-iliac-femoral arteries CT angiography (CTA) examination and had a definite diagnosis of LEAOD due to intermittent claudication or resting pain admitted to Tianjin Hospital from January to December in 2017 were enrolled. The arteries in the aorta as well as iliac were surface-reconstructed, which were analyzed by advanced vascular analysis (AVA) combined with the original images, including SMA trunk, abdominal aorta (AA), left and right common iliac artery (LCIA, RCIA), left and right internal iliac artery (LIIA, RIIA), left and right external iliac artery (LEIA, REIA). The normal reference plane and the maximal stenosis plane were selected, and the stenosis rate of each artery in the reconstruction range was automatically calculated with software. The patient's imaging data were divided into groups with two methods: (1) according to the degree of SMA stenosis, the patients were divided into group I (stenosis degree ≤70%) and group II (stenosis degree > 70%); (2) LEAOD patients with different gender were respectively divided into three groups: middle-aged group (45-59 years old), pre-elderly group (60-74 years old) and elderly group (75-89 years old). The comparison between the stenosis degree of SMA and each artery within the scope of aorto-iliac artery was analyzed with Pearson simple correlation analysis. RESULTS: The incidence of SMA stenosis in all LEAOD patients was 100%. Correlation analysis showed that there was no correlation between the stenosis degree of SMA and AA, LCIA, RCIA, LIIA, RIIA, LEIA, or REIA in group I (n = 64) and group II (n = 6), respectively (r value was -0.021, 0.023, 0.023, -0.137, 0.182, -0.113, 0.141, respectively, in group I, and it was 0.020, -0.560, 0.010, 0.306, -0.204, -0.381, 0.393, respectively, in group II, all P > 0.05). In 52 male patients, there was no correlation between the stenosis degree of SMA and AA, LCIA, RCIA, LIIA, RIIA, LEIA, or REIA in middle-aged group (n = 16), pre-elderly group (n = 27) and elderly group (n = 9), respectively (r value was -0.032, 0.024, 0.324, 0.146, 0.312, 0.008, 0.344, respectively, in middle-aged group, it was -0.108, -0.116, -0.040, -0.249, -0.082, -0.052, 0.096, respectively, in pre-elderly group, and it was 0.182, 0.311, 0.400, 0.360, 0.688, 0.498, 0.406, respectively, in elderly group, all P > 0.05). In 18 female patients, there was also no correlation between the stenosis degree of SMA and above each artery within the scope of aorto-iliac artery in pre-elderly group (n = 11) and elderly group (n = 6), respectively (the r value was -0.170, 0.040, -0.019, 0.152, 0.508, 0.042, 0.456, respectively, in pre-elderly group, and it was -0.660, 0.008, -0.055, -0.056, -0.213, 0.344, 0.011, respectively, in elderly group, all P > 0.05). The correlation in middle-aged group was not analyzed because there was only 1 patient. CONCLUSIONS Although the atherosclerotic changes in LEAOD patients can affect SMA and aorto-iliac artery at the same time, there was no correlation between the stenosis degree of SMA and each artery within the scope of aorto-iliac artery which may due to the differences in the histological structure and hemodynamics among different arteries. SMA atherosclerotic stenosis and occlusion is a relatively independent disease process for LEAOD.
Aged ; Aged, 80 and over ; Computed Tomography Angiography ; Constriction, Pathologic ; Female ; Humans ; Iliac Artery ; Lower Extremity ; Male ; Mesenteric Artery, Superior ; Middle Aged

Objective: To investigate the correlation between the stenosis degree of superior mesenteric artery (SMA) and each artery within the scope of aorto-iliac artery in patients with lower extremity atherosclerotic occlusive disease (LEAOD). Methods: Images of 70 patients who had undergone the aorta-iliac-femoral arteries CT angiography (CTA) examination and had a definite diagnosis of LEAOD due to intermittent claudication or resting pain admitted to Tianjin Hospital from January to December in 2017 were enrolled. The arteries in the aorta as well as iliac were surface-reconstructed, which were analyzed by advanced vascular analysis (AVA) combined with the original images, including SMA trunk, abdominal aorta (AA), left and right common iliac artery (LCIA, RCIA), left and right internal iliac artery (LIIA, RIIA), left and right external iliac artery (LEIA, REIA). The normal reference plane and the maximal stenosis plane were selected, and the stenosis rate of each artery in the reconstruction range was automatically calculated with software. The patient's imaging data were divided into groups with two methods: ① according to the degree of SMA stenosis, the patients were divided into group Ⅰ (stenosis degree ≤70%) and groupⅡ (stenosis degree > 70%); ② LEAOD patients with different gender were respectively divided into three groups: middle-aged group (45-59 years old), pre-elderly group (60-74 years old) and elderly group (75-89 years old). The comparison between the stenosis degree of SMA and each artery within the scope of aorto-iliac artery was analyzed with Pearson simple correlation analysis. Results: The incidence of SMA stenosis in all LEAOD patients was 100%. Correlation analysis showed that there was no correlation between the stenosis degree of SMA and AA, LCIA, RCIA, LIIA, RIIA, LEIA, or REIA in group Ⅰ (n = 64) and group Ⅱ (n = 6), respectively (r value was -0.021, 0.023, 0.023, -0.137, 0.182, -0.113, 0.141, respectively, in group Ⅰ, and it was 0.020, -0.560, 0.010, 0.306, -0.204, -0.381, 0.393, respectively, in group Ⅱ, all P > 0.05). In 52 male patients, there was no correlation between the stenosis degree of SMA and AA, LCIA, RCIA, LIIA, RIIA, LEIA, or REIA in middle-aged group (n = 16), pre-elderly group (n = 27) and elderly group (n = 9), respectively (r value was -0.032, 0.024, 0.324, 0.146, 0.312, 0.008, 0.344, respectively, in middle-aged group, it was -0.108, -0.116, -0.040, -0.249, -0.082, -0.052, 0.096, respectively, in pre-elderly group, and it was 0.182, 0.311, 0.400, 0.360, 0.688, 0.498, 0.406, respectively, in elderly group, all P > 0.05). In 18 female patients, there was also no correlation between the stenosis degree of SMA and above each artery within the scope of aorto-iliac artery in pre-elderly group (n = 11) and elderly group (n = 6), respectively (the r value was -0.170, 0.040, -0.019, 0.152, 0.508, 0.042, 0.456, respectively, in pre-elderly group, and it was -0.660, 0.008, -0.055, -0.056, -0.213, 0.344, 0.011, respectively, in elderly group, all P > 0.05). The correlation in middle-aged group was not analyzed because there was only 1 patient. Conclusions Although the atherosclerotic changes in LEAOD patients can affect SMA and aorto-iliac artery at the same time, there was no correlation between the stenosis degree of SMA and each artery within the scope of aorto-iliac artery which may due to the differences in the histological structure and hemodynamics among different arteries. SMA atherosclerotic stenosis and occlusion is a relatively independent disease process for LEAOD.