RESUMO
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.