AIM:To assess the value of computed tomography duringarterial portography (CTAP) in portal vein-vena cava shunt,and analysis of the episode risk in encephalopathy.METHODS:Twenty-nine patients with portal-systemicencephalopathy due to portal hypertension were classifiedby West Haven method into grade Ⅰ(29 cases),gradeⅡ(16 cases),grade Ⅲ(10 cases),grade Ⅳ( 4 cases).Allthe patients were scanned by spiral-CT.Plane scans,arteryphase and portal vein phase enhancement scans wereperformed,and the source images were thinly reconstructedto 1.25 mm.We reconstructed the celiac trunk,portal vein,inferior vena cava and their branches and subjected themto three-dimensional vessel analysis by volume rendering(VR) technique and multiplanar volume reconstruction(MPVR) technique.The blood vessel reconstructiontechnique was used to evaluate the scope and extent ofportal vein-vena cava shunt,portal vein emboli and thefistula of hepatic artery- portal vein.The relationshipbetween the episode risk of portal-systemic encephalopathyand the scope and extent of portal vein-vena cava shunt,portal vein emboli and fistula of hepatic artery- portal veinwas studied.RESULTS:The three-dimensional vessel reconstructiontechnique of spiral-CT could display celiac trunk,portal vein,inferior vena cava and their branches at any planes andangles and the scope and extent of portal vein-vena cavashunt,portal vein emboli and the fistula of hepatic artery- portalvein.In twenty-nine patients with portal-systemicencephalopathy,grade Ⅰ accounted for 89.7% esophagealvarices,86.2% paragastric varices;grade Ⅱ accounted for68.75% cirsomphalos,56.25% paraesophageal varices,62.5% retroperitoneal varices and 81.25% dilated azygosvein;grade Ⅲ accounted for 80% cirsomphalos,60%paraesophageal varices,70% retroperitoneal varices,90%dilated azygos vein,and part of the patients in grades Ⅱand Ⅲ had portal vein emboli and fistula of hepatic artery-portal vein;grade Ⅳ accounted for 75% dilated left renalvein,50% paragallbladder varices,all the patients had fistulaof hepatic artery- portal vein. CONCLUSION:The three-dimensional vessel reconstructiontechnique of spiral-CT can clearly display celiac trunk,portalvein,inferior vena cava and their branches at any planesand angles and the scope and extent of portal vein-venacava shunt.The technique is valuable for evaluating theepisode risk in portal-systemic encephalopathy. AIM: To assess the value of computed tomography during arterial portography (CTAP) in portal vein-vena cava shunt, and analysis of the episode risk in encephalopathy. METHODS: Twenty-nine patients with portal-systemicencephalopathy due to portal hypertension were classified by West Haven method Grade Ⅰ (29 cases), grade Ⅱ (16 cases), grade Ⅲ (10 cases), grade Ⅳ (4 cases). All patients were scanned by spiral-CT. Plane scans, arteryphase and portal vein phase enhancement scans were performed, and the source images were thinly reconstructed to 1.25 mm. We reconstructed the celiac trunk, portal vein, inferior vena cava and their branches and subjected themto three-dimensional vessel analysis by volume rendering (VR) technique and multiplanar volume reconstruction (MPVR) technique. The blood vessel reconstructiontechnique was used to evaluate the scope and extent ofportal vein-vena cava shunt, portal vein emboli and thefistula of hepatic artery- portal vein.The relationshipbetween the episode risk of portal-systemic encephalopathy and the scope and extent of portal vein-vena cava shunt, portal vein emboli and fistula of hepatic artery-portal veinwas studied .RESULTS: The three-dimensional vessel reconstruction technique of spiral-CT could display celiac trunk, portal vein, inferior vena cava and their branches at any planes and angles and the scope and extent of portal vein-vena cavashunt, portal vein emboli and the fistula of hepatic artery- portalvein. twenty-nine patients with portal-systemicencephalopathy, grade I accounted for 89.7% esophageal varices , Grade II accounted for 68.75% cirsomphalos, 56.25% paraperophageal varices, 62.5% retroperitoneal varices and 81.25% dilated azygosvein; grade III accounted for 80% cirsomphalos, 60% paraesophageal varices, dilated azygos vein, and part of the patients in grades Ⅱ and Ⅲ had portal vein emboli and fistula of hepatic artery-portal vein; grade Ⅳ accounted for 75% dilated left renalvein , 50% paragallbladdeCONVENTION: The three-dimensional vessel reconstruction technique of spiral-CT can clearly display celiac trunk, portal vein, inferior vena cava and their branches at any planes and angles and the scope and extent of portal vein-venacava shunt.The technique is valuable for evaluating the episode risk in portal-systemic encephalopathy.