Objective To investigate multi-slice spiral CT manifestations and its diagnostic value of extragastrointestinal stromal tumor(EGIST).Methods CT data in 19 patients with EGIST proved pathologically were retrospectively reviewed.Results Of the 19 cases,the lesions located in reteoperitoneum in 8 cases,adrenal,greater omentum,omentum and mesentery in one case respectively,mesentery in 4 cases,and abdominal cavity in 4 cases.2 cases were benign,4 cases were potential malignant,and 13 cases were malignant.The size of tumors ranged 4.1～35 cm.The tumors were round or oval in 5 cases,lobulated in 5 cases and irregular in 9 cases.The tumors in 4 cases were uniform density on plain CT scans,1 case of uniform and moderate enhancement,1 case of non-uniform enhancement,2 cases of apparent enhancement as ring on contrast-enhanced CT scans;15 cases showed unhomogeneous density,on contrast-enhanced scans,moderate or remarkable enhancement was seen in the parenchyma of the tumor,while no enhancement was revealed in the necrosis and cystic areas of the tumors.Conclusion EGIST have certain imaging characteristics and MSCT was valuable in diagnosing and differential diagnosing EGIST.

Purpose To investigate the MSCT diagnosis and differential diagnosis of rare pancreatic tumors.Materials and Methods The MSCT features were analysied respectively of 31 cases with pancreatic tumors confirmed by surgery and pathology.Results There were serous cystadenoma in 7 cases,mucinous cystadenoma in 9 cases,mucinous cystadenocarcinoma in 1 case,solid-pseudopapillary tumor in 8 cases,islet cell tumor in 4 cases,carcinoid tumor in 1 case and intraductal papillary adenocarcinoma 1 case.The MSCT appearances were different each other.Conclusion MSCT is very helpful in diagnosis and differential diagnosis for the rare pancreatic tumors.

Objective To investigate the value of distinguishing small clear cell renal cell carcinoma and high-attenuation renal cysts by applying unenhanced CT value and homogeneity of the esions.Methods Retrospective analysis of 38 cases of small renal cell carcinoma confirmed by operation and pathology and 58 cases of high-attenuation renal cyst that were confirmed by enhanced CT,and measured CT value and homogeneity of each mass,and did statistical analysis for corresponding datas.Results The CT value of small clear cell renal cell carcinoma was (35.5±10.1)HU (range 20-60.3 HU).The CT value of high-attenuation renal cysts was (70±1 5.2)HU (range 29-95 HU).Difference of the two groups had statistical significance (P <0.001).For high-attenuation re-nal cysts,uniform density often can be seen(47 cases,81.03%).For small clear cell renal cell carcinoma,uneven density often can be seen (29 cases,76.32%).Difference of the two groups had statistical significance (P <0.001).When optimal cut-off of CT value determined by ROC was 5 1.5 HU,the sensitivity and specificity were 89.7% and 92.1%,respectively.Conclusion Unenhanced CT may be helpful in distinguishing small clear cell renal cell carcinoma and high-attenuation renal cysts,which can provide reasona-ble suggestions on the next identification examinations.

Objective Toexplore the findings of bile flow artifacts (BFA)on MR cholangiopancreatography(MRCP). MethodsEighty five patients with normal common bile duct (CBD)and 95 patients with dilated CBD who had MRCP examination were studied retrospectively. Findings of BFA on original thin images of MRCP were recorded. Date were tested by Chi-square test and Spearman ceefficient of rank correlation analysis. ResultsThe rate of BFA in CBD with normal group was 38. 8％ ( 33/85 ), in dilated group was 83.2％ (79/95), there was statistically significant difference between them( x2 ＝ 37. 512,P ＝ 0. 000). BFA was not observed when the diameter of CBD was no more than 4 mm. BFA was partly observed when the diameter of CBD was 4 mm ＜ ψ≤ 8 mm, single- string sign was predominant findings (52.6％ ,30/57 ). Three-string sign was predominant findings in CBD with slight-dilated group ( 85.7％,36/42). Multi-string sign was predominant findings in CBD with medium-dilated group (84. 6％, 22/26 ).There was statistically significant difference between each groups ( x2 ＝ 284. 561, P ＝ 0. 000 ).BFA had different manifestations with CBD of different diameter, there was relative between them ( r ＝ 0. 553, P ＝0. 000). ConclusionBFA can occur in CBD with normal diameter. CBD with dilated group has higher rate of BFA than CBD with normal diameter. Manifestations of BFA are relative with the diameter of CBD.

Objective To investigate the imaging characteristics of autoimmune pancreatitis (AIP)and its diagnostic value.Methods Imaging examinations and clinical data of 13 patients with AIP were reviewed retrospectively.Results All patients had enlargement of pancreas either diffusely ( n =11 ) or focally in pancreatic head ( n =2 ).The swollen pancreas was of homogeneous density on CT scan ( n =13 ),hypointense on T1-weighted images and mildly hyperintense on T2-weighted images in 4 patients.It was demonstrated as mild enhancement on artery phase of dynamic imaging and progressive enhancement on portal and delayed phase images.Capsule-like enhanced rim was presented around the pancreas in 9 patients.Stricture or obliteration of the common bile duct located in pancreatic head was found in 10 patients accompanied by intrahepatic bile duct dilation.Pancreatic duct was invisible on axial images in 11 cases.Among the 6 patients underwent MRCP,it was showed diffuse and irregular narrowing of the main pancreatic duct and stricture of common bile duct located in pancreatic head in 4 cases.ERCP showed diffuse and irregular narrowing of the main pancreatic duct in 7 cases.Extra-pancreatic lesion included veins around pancreas involvement in 8 cases;multiple low density renal lesions in 6 cases; retroperitoneal fibrosis in 2 cases; stricture of hilar duct,interstitial lung disease and ankylosing spondylitis in 1 case,respectively.Conclusions AIP shows some characteristic imaging features,and imaging examinations play an important role in the diagnosis of AIP.Recognition of extra-pancreatic lesions aids in the correct diagnosis of AIP.