Objective To investigate clinical value of dual-source CT angiography (DSCTA)in diagnosis and following-up obser-vation after endovascular exclusion (EVE)of Stanford type B aortic dissection (AD).Methods 63 cases with type B aortic dissection were diagnosed by DSCTA,and 24 cases among these cases underwent EVE were following-up observed by DSCTA.Imaging recon-struction and analysis were finished at special workstation.All CT findings of dissection were carefully observed in every case,CT values of true and false lumens were measured at arterial-phase.The length and the width of proximal neck,and the maximum di-ameter of AD were measured in those cases that initial crevasse located at aortic arch or proximal descending thoracic aorta.The out-comes and complications of 24 cases underwent EVE were focused.Results The extension of dissection,the site of crevasse,mor-phological features of true and false lumens and tearing intimal flap,and involving main branches of aorta were accurately shown by DSCTA.Average CT value of true lumen was higher than false lumen at arterial-phase in all cases (P=0.000).In 60 cases that ini-tial crevasse located at aortic arch or proximal descending thoracic aorta,the length and the width of proximal neck of dissection changed from 0.3 cm to 9.6 cm(average 3.4 cm)and from 2.3 cm to 3.8 cm(average 2.9 cm)respectively,and the maximum di-ameter of AD was between 3.1 cm and 9.0 cm(average 5.3 cm).AD after EVE did not unceasingly enlarge in all 24 cases,false lu-men shrinked in 1 1 cases,thrombus in false lumen added in most cases,stent endoleaking were observed in 1 1 cases.Conclusion DSCTA with convenient,effective and non-invasive advantages,is one of important imaging methods in diagnosis and following-up observation after EVE of type B aortic dissection.

Objective To review the CT appearances and important differential diagnoses of various primary and secondary mesenteric neoplasms.Methods By describing the mesenteric anatiomy and major routes for the dissemination of metastatic mesenteric tumors, the article presents both the common and rare types of various primary and secondary mesenteric neoplasms, and addresses the characteristic CT appearances and important aspects of the differential diagnosis.Results CT study, especially the multi-slice spiral CT (MSCT), along with the clinical history and other related information, can nicely depict various mesenteric tumors and well differentiate them from infectious, inflammatory or vascular processes affecting the mesentery.Conclusion CT is the imaging method of choice for the evaluation of tumors of small bowel mesentery.

Objective To review the various imaging modalities and their appropriate applications in the preoperative evaluation of both donors and recipients in liver transplantation (LT). Methods All the relevant literatures were reviewed. Different kinds of imaging modalities have been used in potential LT donors and recipients to assess the volume, the parenchyma and the vasculature of the liver, the biliary system, and the extrahepatic region of the upper abdomen and beyond. The techniques, the imaging findings, and the merits and shortcomings of various imaging modalities were presented.Results Traditional imaging techniques are still of valuable, while CT can provide rich and accurate information. "One-stop" comprehensive MR examination is emerging as the method of choice for the preoperative evaluation LT recipients and donors. Conclusion Each imaging method has its merits and limitations. Those imaging methods which can provide accurate and comprehensive information are likely to have better application future.

Objective To analyze MR imaging findings of avascular necrosis of the femoral head(ANFH)with low-field MR unit.Methods MRI appearances of 35 cases of ANFH confirmed by clinical or pathology were analysed.Results There were 56 hips with "line sign" in 35 cases(58 hips)including "single line sign" in 18 femoral heads and "double line sign" in 38,and there were 2 hips without "line sign".Twenty-six femoral heads had marrow edema.According to Mitchell's grade:there were 15 hips in A grade,21 hips in B grade,13 hips in C grade and 9 hips in D Grade.Conclusion Low-feild MR imaging is of significant value in diagnosing ANFH early.

Objective To investigate the diagnostic value of low-field MR imaging in lumbar disc degeneration with end-plate osteochondritis. Methods Imaging data of 504 patients with lumbar disc degeneration diagnosed by MRI were retrospectively analyzed. Among these cases, the total of 330 end-plate osteochondritis in 148 patients was found. According to MR signal findings of end-plate and it's adjacent vertebra, the lesions were classified as 4 types. Results 330 end-plates were involved in 148 patients,including type I in 68(20.6%),type II in 53(16.1%),type III in 174(52.7%) and type IV in 35(10.6%).Among all 148 patients,the end-plates at one lumbar disc,two disci and over three disci involved in 98(66.2%),42(28.4%) and 8(5.4%),respectively.The lesions were usually found in the lower lumbar vertebra.Conclusion MR imaging could accurately show the end-plate osteochondritis and degenerative lumbar disc.

Objective To investigate the CT imaging features of pancreatic fatty replacement and its clinical significance. Methods Three patients with pancreatic fatty replacement detected by CT were retrospectively analyzed. CT examination included plain scan and contrast-enhanced scanning at the arterial and portal venous phases. The shape, size, density, pancreatic lobulation and interlobular spaces, course of the pancreatic duct were carefully observed. The clinic and laboratory data were also analyzed to determine the clinical significance of pancreatic fatty replacement. Results ①Imaging features: Two patients had complete fatty replacement involving the entire pancreas, another one had most fatty replacement sparing the posterior aspect of head and tail. Two patients had regular configuration of pancreas. The size of pancreas was slightly enlarged in 2 patients. Lobular atrophy and widening of interlobular spaces were present in all 3 patients. The pancreatic duct was normal in 3 patients. ②Clinic findings: Chronic diarrhea was present in 3 patients. Two patiens had diabetes (one had chronic cholangitis with choledochal lithiasis), another one had small stone in the common bile duct. Serum lipase was low in 3 patients, of which one had low serum amylase. Conclusion Pancreatic fatty replacement demonstrates certain characteristic CT appearances, and is usually associated with disturbances of both the endocrine and exocrine functions of the pancreas.

Objective By using multi detector row spiral CT (MDCT), to investigate the CT imaging features of inflammatory diseases in retroperitoneal space with correlation of radiological anatomy.Methods The clinical and laboratory dada of 30 patients with proven inflammatory diseases of retroperitoneal space were collected. All patients underwent MDCT plain scanning and portal venous acquisition. CT imaging data generated at portal venous phase were processed with coronal, sagittal and oblique multi planar reformation (MPR) technique.Results Acute pancreatitis and various types of renal infection were the two main sources of retroperitoneal inflammation. Depending on the specific anatomic locations, retroperitoneal inflammation of different subspaces demonstrated characteristic imaging features. Spreading of inflammatory process across subspaces was also quite common.Conclusion MDCT is the imaging method of choice to depict comprehensively and clearly the inflammatory diseases of various retroperitoneal spaces.

Objective To evaluate the clinical value of magnetic resonance cholangiopancreatography (MRCP) in diagnosis of extrahepatic bile duct obstruction. Methods MRCP images of 42 patients presented clinically with obstructive jaundice were retrospectively reviewed to assess the lumen morphological abnormalities of benign versus malignant bile duct obstructions, with clinical pathological correlation. Results The bile duct of the 30 cases of benign biliary obstruction presented regular and symmetric dilation, gradual tapering,regular thickening and had a “beak like” tip. The accuracy of MRCP for evaluating the site and the etiology of the benign biliary obstruction were 100%(30/30) and 97%(29/30) respectively. The bile duct of the 12 cases of malignant biliary obstruction presented irregular and asymmetric dilation,abrupt narrowing or iterruption,irregular thickening and had “dual duct sign”. The accuracy of MRCP for evaluating the site and the etiology of the malignant biliary obstruction were 100%(12/12) and 92%(11/12) respectively. Conclusion MRCP is the noninvasive technique of choice with excellent accuracy for the evaluation of obstructive biliary pathology.

Objective To evaluate the value of MR imaging with a contrast enhanced multi phasic isotropic volumetric interpolated breath hold examination (VIBE) in diagnosis of primary liver carcinoma. Methods Thirty two consecutive patients with surgical pathologically confirmed 42 foci of primary carcinoma of liver underwent comprehensive MR examination of the upper abdomen, routine two dimensional (2D) T1WI and T2WI images were acquired before administration of Gd DTPA for contrast enhancement. Then, contrast enhanced multi phasic VIBE was acquired followed by 2D T1WI images. The lesion appearances on hepatic arterial, portal venous and equilibrium phases of VIBE sequence were carefully observed along with delineation of hepatic arterial and portal venous structures. The lesion detection rates and lesion characterization ability were compared among various MR sequences. Results 33(78.6%), 30(71.4%), 38(90.5%) and 42(100%) foci were displayed respectively on T2WI, non enhanced T1WI, enhanced T1WI and enhanced 3D VIBE images ( P

Objective To investigate the value of multiple sequential MRI in the differential diagnosis of vater ampulla carcinoma (VPC).Methods MRI data of 53 patients with VPC confirmed by surgery and pathology were analyzed retrospectively,which included 17ampullary carcinomas,15 pancreatic head carcinomas,10 duodenal papillary carcinomas and 11 distal common bile duct carcinomas.All patients underwent routine MRI plain scan,MRCP and multi-phase dynamic enhancement scan for the upper abdomen.The morphological characteristics and model of multi-phase dynamic enhancement of the tumor,and the morphological changes of pancreaticobiliary duct were focused,and relevant data were also measured.Results The differences of tumor size,central location,and signal homogeneity among the four different histological types showed statistical significance(P＜0.05),and their patterns of multi-phase dynamic enhancement also had differences.Double-segment sign was most found in VPC (26/53),four-segment sign was easy showed in pancreatic head carcinoma (8/15)and three-segment sign in distal common bile duct carcinoma (8/11).Beak sign was common seen in ampullary carcinoma(10/17),rat-tail sign was easy discovered in pancreatic head carcinoma (7/15) and truncated sign in distal common bile duct carcinoma(10/11).Diameter of major pancreatic duct in pancreatic head carcinoma was maximum and minimum in distal common bile duct carcinoma,and their difference had statistical significance(P＜0.05).Distance between obstructive end of bile common duct and major papilla of duodenum,and between obstructive end of major pancreatic duct and major papilla of duodenum as well as the pancreaticobiliary conjunction angle in pancreatic head carcinoma and distal common bile duct carcinoma were greater than that in ampullary carcinoma and duodenal papillary carcinoma.Conclusion MRI can prominently demonstrate various imaging characteristics of VPC with different histological origins.It is very valuable in the differential diagnosis of VPC with different histological types by comprehensive analysis of these findings.