Objective To study the predetermination value of multi-slice spiral CT for showing the major blood vessels,bile and pancreatic ducts around normal duodenal papilla before EST.Methods A 16-slice spiral CT was used to perform 28s and 68s enhanced scan for normal structures surrounding duodenal papilla in 30 subjects.Post-processing was done to the raw data with thin-slice maximum intensity projection (TSMIP) and thin-slice average intensity projection (TSAIP),and then the structure of bile and pancreatic ducts,duodenal artery and pancreatic-duodenal conjunction were reconstructed.The reconstructed images were double-blind evaluated.Distances between papilla and upper,front,and behind edge of the pancreatic-duodenal conjunction,situation of the duodenal papilla artery and the distance from the papilla artery end to the papilla were recorded.Results After dual-phase enhanced scan,the post-processing results for the images of the surrounding structure of pancreatic and duodenal papilla were stable and the results of double-blind evaluation were consistent.Image scores of the arteries surrounding duodenal papilla and pancreatic duct at 28th second were significantly higher than those of 68th second,whereas bile duct and the ampulla structure image scores of 68th second were higher.TSMIP of local vascular structure could display anterior-superior pancreatic-duodenal artery (ASPDA) in 93.3％ of the subjects,posterior-superior pancreatic-duodenal artery (PSPDA) in 73.3％,inferior pancreatic-duodenal artery (IPDA) in 73.3％,duodenal-papillary artery (DPA) in 56.7％,bile duct in 96.7％,pancreatic duct in 90.0％ aud pancreatic and duodenal parenchima in 100.0％.The DPAs all started from PSPDA origin and down to papilla,with only 2 cases of 30 (6.7％) reached the upper edge of the duodenal papilla.Others showed arteries turned thin obviously at 12 mm above the papilla; the normal common bile duct can be tracked to the opening of the papilla.The Coronal Oblique TSAIP imaging showed the distance from the duodenal papilla-bile duct ending to the lower edge of the pancreatic-duodeual upper conjunction was 15.7±1.9 mm.Distance from papilla to the front edge of pancreatic-duodenal conjunction was 16.6±3.2 mm and to the behind edge was 1.7±0.4 mm.Distance (depth) from the inner edge of the papilla to the bile-pancreatic conjunction was 8.0±1.7 mm.Conclusion The 3D reconstruction of the Multi-slice spiral enhancement CT Imaging can providc high quality images of relative vascular,bile-pancreatic and obvious surrounding structures to the forthcoming operation.Massive hemorrhage and perforation risks of EST can be evaluated based on the vascular distribution and directions around duodenum and pancreas and the bile duct imaging.

Objective To explore the differences among CT angiography(CTA) at different doses in both lower extremity arteries,and the relationship among volume rendering(VR) image quality,CT number and standard deviation(SD) value.Method CTA in lower extremity artery was performed in 90 patients.The participants were randomly divided into three groups,including a routine group (120 kV,150 mAs),120 kV and 80 mAs group,and 100 kV and 130 mAs group with 30 cases in each group.The images were processed with VR and classified into three degrees,the first class,the second class and the third class,and VR image quality levels of three groups were compared.The receiver operating characteristic curve(ROC) was used to analyze the correlation among VR image quality level,CT number and SD value.Results The percentage of VR image level at the first class was 93.3％ in the routine group,86.6％ in the 120 kV and 80 mAs group and 96.6％ in the 100 kV and 130 mAs group.According to the correlation analysis between the SD value and VR image quality of CTA in lower extremity artery,the area under curve in ROC analysis was 0.9078.According to the correlation analysis between the CT number and VR image quality of CTA in lower extremity artery,the area under curve in ROC analysis was 0.9116.Conclusions The low-dose CAT in lower extremity artery is feasible.Application of 100 kV and 130 mAs could ensure better image quality.

Objective To explore the feasibility and reasonable of low-dose scan on abdominal angiography in 64-slice spiral helical CT. Methods Phantom test: at 120 KV and from 200 mAs to 30 mAs at an interval of 10 mAs in each image acquisition, it was measured standard deviation (SD) of CT number, high contrast resolution and low contrast resolution, and then analyzed the relationship between the three parameters and the mAs values. Three mAs values were chosen to undertake clinical analysis.Clinical analysis: 90 randomly selected objects with abdominal angiography were divided into three groups,scanning with above three mAs values.Measurement of the SD value at the plain scan images was performed and the enhanced low-dose scan images were used post-processing with three-dimensional volume reconstruction (VR). The VR images were classified into three grades (excellent, moderate, bad) with the blind evaluation of three CT radiologists. The quality-correlation analysis was used between the standard deviation (SD) values of plain scan image and abdominal angiography VR image. Results According to the quality-correlation analysis between the standard deviation (SD) value of plain scan image and abdominal angiography VR image, the area under curve in receiver-operated characteristic (ROC) analysis was 0.921, 0.906 and 0.893 in each three group, respectively. Conclusions The low-dose scan of abdominal angiography is feasible. 80mAs can ensure better image quality. The enhanced scan probably can use 60mAs when the SD value is less than 5.78 in the plain scan; but when the SD value of plain scan is greater than 11.8, the enhanced scan is used best 100 mAs or higher.

OBJECTIVE: To analyze the dynamic changes of chest CT images of patients with corona virus disease-19 (COVID-19). METHODS: Fifty-two cases of COVID-19 were admitted in the First Affiliated Hospital of Zhejiang University School of Medicine. The consecutive chest CT scans were followed up for all patients with an average of 4 scans performed per patient during the hospitalization. The shortest interval between each scan was 2 days and the longest was 7 days. The shape, number and distribution of lung shadows, as well as the characteristics of the lesions on the CT images were reviewed. RESULTS: The obvious shadows infiltrating the lungs were shown on CT images in 50 cases, for other 2 cases there was no abnormal changes in the lungs during the first CT examination. Ground-glass opacities (GGO) were found in 48 cases (92.3%), and 19 cases (36.5%) had patchy consolidation and sub-consolidation, which were accompanied with air bronchi sign in 17 cases (32.7%). Forty one cases (78.8%) showed a thickened leaflet interval, 4 cases (7.6%) had a small number of fibrous stripes. During hospitalization, GGO lesions in COVID-19 patients gradually became rare, the fibrous strip shadows increased and it became the most common imaging manifestation. The lesions rapidly progressed in 39 cases (75.0%) within 6-9 days after admission. On days 10-14 of admission, the lesions distinctly resolved in 40 cases (76.9%). CONCLUSIONS The chest CT images of patients with COVID-19 have certain characteristics with dynamic changes, which are of value for monitoring disease progress and clinical treatment.

OBJECTIVE: To analyze the dynamic changes of chest CT images of patients with coronavirus disease 2019 (COVID-19). METHODS: Fifty-two cases of COVID-19 were admitted in the First Affiliated Hospital of Zhejiang University School of Medicine. The consecutive chest CT scans were followed up for all patients with an average of 4 scans performed per patient during the hospitalization. The shortest interval between each scan was 2 days and the longest was 7 days. The shape, number and distribution of lung shadows, as well as the characteristics of the lesions on the CT images were reviewed. RESULTS: The obvious shadows infiltrating the lungs were shown on CT images in 50 cases, for other 2 cases there was no abnormal changes in the lungs during the first CT examination. Ground-glass opacities (GGO) were found in 48 cases (92.3%), and 19 cases (36.5%) had patchy consolidation and sub-consolidation, which were accompanied with air bronchi sign in 17 cases (32.7%). Forty one cases (78.8%) showed a thickened leaflet interval, 4 cases (7.6%) had a small number of fibrous stripes. During hospitalization, GGO lesions in COVID-19 patients gradually became rare,the fibrous strip shadows increased and it became the most common imaging manifestation. The lesions rapidly progressed in 39 cases (75.0%) within 6-9 days after admission. On days 10-14 of admission, the lesions distinctly resolved in 40 cases (76.9%). CONCLUSIONS The chest CT images of patients with COVID-19 have certain characteristics with dynamic changes, which are of value for monitoring disease progress and clinical treatment.
Betacoronavirus ; isolation & purification ; China ; Coronavirus Infections ; diagnostic imaging ; pathology ; Disease Progression ; Humans ; Pandemics ; Pneumonia, Viral ; diagnostic imaging ; pathology ; Tomography, X-Ray Computed