Objective To explore the diagnostic value of dual syringe and dual-channel direct multi-slice computed tomography venography(MSCTV) for lower extremity deep venous obstructive disease.Methods 100 patients highly suspected deep vein thrombosis by clinic wereunderwent dual syringe and dual-channel direct MSCTV.The original data processed with technology of subtraction,and put into workstation and reconstructed with maximum intensity projection(MIP),multiplanar reformation(MPR) and volume rendering (VR).Images of deep venous obstructive lesions were analysed and graded.All patients were underwent DSA in one week.Results Direct MSCTV showed that the reconstructed images and the vascular contrast were very clear.In the evaluation of deep venous,excellent proportion was 95 ％ for the inferior vena cava,94 ％ for the common iliac vein,95 ％ for the external iliac vein,95.5 ％ for the femoral vein,96.5％ for the popliteal vein and 92 ％ for the low leg vein.Direct MSCTV displayed complete and regular vein in 8 normal patients,92 cases displayed different parts and different degrees of thrombosis.On original axial images,eccentric filling defect of vascular were showed (there were 64 multiple vein occlusion cases and 28 solitary obstruction cases).The occlusion locations in deep venous were as following:3 in the inferior vena cava,67 in the common iliac vein,28 in the external iliac vein,50 in the femoral vein,26 in the popliteal vein,89 in the anterior tibial vein,35 in the posterior tibial vein and 5 in the peroneal vein.There were 7 normal patients and 93 patients with different parts and different degrees of thrombosis.Conclusion Direct MSCTV can accurately show deep vein thrombosis,which image is clear and reliable for displaying the scope and extent of lesions of the vascular and whether the collateral circulation established.Direct MSCTV has a significant clinical value in diagnosing the thrombotic disease of deep vein obstructive lesions.

Objective To compare the bone mineral density and age-related bone loss rate of thoracic and lumbar vertebrae using quantitative CT(QCT),and to explore the feasibility of measuring bone density and bone loss rate using thoracic QCT.Methods A total of 708 patients who underwent full abdominal CT scans due to trauma,acute abdominal disease,and health examination from March 2022 to March 2023 were selected.The average BMD of T10 to L3 vertebral bodies were measured using quantitative CT software.The subjects were divided into several age groups according to the age of every 10 years.The average bone density and the age-related annual rate of bone density loss of the thoracic and lumbar vertebrae for each group were computed,the correlation analysis between thoracic and lumbar BMD and age was conducted using Pearson correlation analysis.Results The peak BMD for both males and females was in the 20 to 29 years age group.After the age of 30,the bone density of the thoracic and lumbar vertebrae began to decrease to varying degrees.For females aged 80 to 89,the cumulative bone loss rate for the thoracic and lumbar vertebrae was 60.61%and 61.34%,respectively,while for males,it was 44.45%and 49.35%,respectively.The BMD of the thoracic and lumbar vertebrae in both males and females showed a negative correlation with age(P<0.01).There was a significant positive correlation between the bone mineral density of the thoracic and lumbar vertebrae(for males,r = 0.96;for females,r = 0.98;P<0.01).Conclusion Both thoracic and lumbar QCT accurately displayed BMD and bone loss in different age groups,and thoracic QCT could be used as a method for evaluating and monitoring bone loss.