Objective To investigate low-field MRU scanning technique to optimize the quality of images.Methods Airis-Ⅱcomfort open 0.3T low-field MR imaging system made by HITACHI company were used in the examination.The quality of images was improved when combining 3D-FSE sequences.Results MRU examination was implemented in all 33 cases and all the cases had distinct images except two.The total diagnostic accuracy was 98.0%.The accuracy of MRU in the detection of the degree and location of ureter obstruction was 100%.Conclusion This study shows that if patients are well-prepared before examination,low-field MR can also produce good MRU images of high quality by using manifold scanning techniques and suitable technical parameters.

Objective To evaluate the diagnostic value of the low field MRCP in obstructive jaundice by comparing its result with that of US and CT. Methods 55 cases of obstruction jaundice patients proved by clinical diagnosis were studied and compared the collected original diagnosis results by low filde MRCP with US and CT.Results Of 55 cases of obstructive jaundice, 30 were cholelithiasis ,21 were tumors and 4 belonged to the other type. The accuracy of MRCP for defining the site of obstruction was 100%. The accuracy for identifying the cause of obstruction was 81.8%.Conclusion The low filde MRCP can accurately define the obstructive site in biliary obstructive disease .When used together with 2D single-shot breath-hold MRCP , T 2WI, T 1WI and 3D-FSE MRCP shows high accuracy and sensitivity in diagnosing obstructive jaundice.

Objective To investigate imaging parameters on low field MRCP and to optimize the quality of images.Methods MRCP in 77 cases were performed using Airis-Ⅱcomfort open 0.3T low field MR imaging system made by HITACHI company.3D-FSE combined with 2D single-shot breath-hold FSE sequences were used.The 3%～5% compound solution of Gd-DTPA was taken to restrain the hige signals from remaining liquid in stomach.Results MRCP examination was succeeded in all 77 cases and the images in all cases but 2 were fine for diagnosis.The total diagnostic accuracy was 79.2%.The accuracy of MRCP in the detection of the degree and location of pancreaticobiliary duct obstruction was 100%. Conclusion The distinct MRCP images can be obtained with low field MR system using combination of several scanning techniques and proper scanning parameters,and also patients have to prepare fully.

Objective To evaluate the diagnostic value of MRI in hepatic echinococcosis.Methods MRI features of 37 cases with hepatic echinococcosis proved by operation and pathology were analysed in comparison with that of CT.Results The hepatic echinococcosis could be divided into five types according to the manifestations of CT and MRI:simple cyst in 8 cases,multiple daughter cyst in 13 cases,ruptured cyst in 7 cases,consolidated and calcified cyst in 4 cases and mixed cyst in 5 cases.Conclusion MRI can clearly show and determine the location,size,form,number and types of hepatic echinococcosis,that are helpful for the plan of operation.

Objective To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) features of intestinal-type and pancreaticobiliary-type invasive adenocarcinomas of the ampullary region (IAARs) and investigate the value of the differential diagnosis.Methods The retrospective cross-sectional study was adopted.The clinicopathological data of 33 patients with IAAR who were admitted to the Lanzhou University Second Hospital (20 patients) and Affiliated Hospital of Ningbo University (13 patients) between September 2013 and August 2015 were collected.The patients underwent plain and enhanced scans of CT and MRI.(1) Observation indictors included tumor size,shape,growth pattern,boundary,internal structure,density and/or signal,style and/or degree of contrast enhancement,changes of bile and/or pancreatic duct,invasion and metastasis.(2) The clinical and imaging features of intestinal-type and pancreaticobiliary-type IAARs were compared.(3) Operation was performed after preoperative examinations,and patients received the postoperative pathological examination and immunohistochemistry.Measurement data with normal distribution were presented as x-±s.Comparison between groups was evaluated with an independent sample t test,and count data were analyzed using the chi-square test.Results (1) Of 33 patients with IAAR,19 received plain scan of CT,including 17 receiving simultaneous enhanced scan of CT.Fourteen patients [9 receiving diffussion-weighted imaging (DWI) sequence of MRI] received plain scan of MRI,including 12 receiving simultaneous enhanced scan of MRI.The maximum diameter of IAAR in 33 patients was (2.8 ± 1.4)cm.Fourteen tumors were round-like or oval shape and 19 tumors were irregular shape.The intracavity type,extracavity type and mixed type of tumors were detected in 24,6 and 3 patients,respectively.There were clear boundary of tumors in 17 patients and fuzzy boundary of tumors in 16 patients.Tumors of 5 patients had appeared necrotic and/or cystic,no hemorrhage or calcification was found in tumors of 33 patients.Density and signal of tumors were homogeneous in 18 patients and inhomogeneous in 15 patients.Of 29 patients receiving enhanced scan of CT or MRI,homogeneous enhancement and inhomogeneous enhancement were respectively detected in 14 and 15 patients,and mild enhancement,moderate enhancement and no enhancement were respectively detected in 15,14 and 0 patients.Tumors of 9 patients in DWI showed slightly high or high signal.Thirty patients had secondary bile duct dilatation (3 with mild dilatation,6 with moderate dilatation and 21 with severe dilatation),and 3 patients had no changes of bile duct.Twenty-six patients had secondary pancreatic duct dilatation and 7 had no changes of pancreatic duct.Sixteen patients had tumor invasion to pancreatic tissues and 7 had lymph node metastases.(2) Of 33 patients with IAAR,19 had intestinal-type IAAR (8 males and 11 females) and 14 had pancreaticobiliary-type IAAR (11 males and 3 females).There was statistically significant difference in the gender between the 2 types of IAAR (x2=4.388,P ＜ 0.05).The intracavity type,extracavity type and mixed type of tumors,clear boundary and fuzzy boundary of tumors,homogeneous and inhomogeneous density and/or signal of tumors,with and without tumor invasion to pancreatic tissues were respectively detected in 17,0,2,13,6,14,5,6,13 patients with intestinal-type IAAR and 7,6,1,4,10,4,10,10,4 patients with pancreaticobiliary-type IAAR,with statistically significant differences between the 2 types of IAAR (x2=9.971,5.125,6.617,5.125,P ＜ 0.05).(3) All the patients underwent surgery and received comprehensive diagnosis and tumor classification after pathological examination and immunohistochemistry.Conclusion There are certain characteristics of CT and MRI in intestinal-type and pancreaticobiliary-type IAARs,and gender,tumor growth pattern,boundary,density and/or signal,tumor invasion to pancreatic tissues have certain reference values for the differential diagnosis of intestinal-type and pancreaticobiliary-type IAARs.

Objective To study the imaging findings of unexpected splenic autotransplantation after splenectomy and to improve diagnostic accuracy of splenic autotransplantation.Methods The findings of 10 patients with splenic autotransplantation confirmed by histology in our hospital were retrospectively reviewed.In 7 patients CT and plain and dynamic enhanced MRI scanning were carried out,and in 2 of them 99mTc-DRBC scanning were also done.In 3 patients,plain and dynamic enhanced CT scannings were done.Results (1) Multiple lesions were detected in 7 patients and a single lesion in 3 patients.The masses were round and oval.The nodules were in the splenic fossa in 9 patients,in the pancreatic tail in 4 patients,in the right liver in 2 patients and in other of parts of the abdominal cavity in 2 patients.These nodules varied in size and 94.6％ showed a maximum diameter of less than 3 cm; (2) The findings on CT and MR:all the nodules were homogeneous with soft tissue density.There was no cystic degeneration,necrosis and calcification.In one patient with a nodule in the pancreatic tail,there was a slightly short T1 and short T2 signals.Other nodules showed long T1 and long T2 signals.All the signals from the nodules were homogeneous and their outlines were clear.In a patient with a nodule in the right liver,the blood supply came from the abdominal aorta.There was a surrounding thin layer of low-density ring which showed long T1 and long T2 signals.The enhanced features on CT and MR were similar.The nodules showed homogeneous or inhomogeneous enhancement in the arterial phase,with continuous homogeneous enhancement in the portal venous phase,with an obvious decline in the delayed phase;(3) The findings of 18 F-FDG PET:The nodules had obvious increase in FDG uptake.Conclusions In patients with a history of splenic trauma or splenectomy,abdominal nodules with multiple,homogeneous density or signal,clear outline,enhanced features similar to spleen,splenic autotransplantation should be considered.99mTc-DRBC scanning is helpful in the diagnosis of splenic autotransplantation.

Objective To discuss the MSCT diagnosis and differential diagnosis of primary ureteral carcinoma and non-specific u-reteritis.Methods The pre-contrast and three-phase post-contrast MSCT scans were performed in a group of 12 patients with prima-ry ureteral carcinoma and 5 patients with non-specific ureteritis confirmed by pathology.The MPR,CPR,CTU images were genera-ted from raw data.The MSCT image feature of the primary ureteral carcinoma and non-specific ureteritis were observed respective-ly.Results ①1 2 cases of primary ureteral carcinoma pathologically diagnosed as transitional cell carcinoma,The manifestations of MSCT:9 cases (9/12)showed irregular thickened wall and eccentricity lumen stenosis,5 cases had soft tissue mass in lumen,3 ca-ses (3/12)showed irregular thickened wall and central lumen stenosis.The lesions lumen was significant stenosis,edges and broken ends were irregular.②The non-specific ureteritis manifestations of MSCT:1 case (1/5)showed irregular thickened wall and eccen-trical lumen stenosis;3 cases (3/5)showed irregular thickened wall and central lumen stenosis,and the edge of obstruction was rel-atively smooth.1 case (1/5)prompted hydronephrosis and hydroureter.The lesions lumen was still relatively smooth,had no sig-nificant thickening.③On non-enhanced CT,primary ureteral carcinoma attenuation was equal to the non-specific ureteritis (P>0.05).The degree of enhancement was higher than non-specific ureteritis during all enhanced phases (All P<0.05).Conclusion Main performance characteristics of primary ureteral carcinoma and non-specific ureteritis can both cause the ureteral wall thickening in different appearances and degrees.The MSCT enhanced scan with varies images processing techniques such as MPR,CPR and CTU showed some clinical application potentiality in both diseases diagnosis and discrimination.

Retrospective analysis of multi-slice computed tomography (MSCT) manifestations were conducted for 8 cases of pathologically confirmed primary pulmonary sarcomatoid carcinoma.And the relevant literature was also reviewed.The lesion sites were right upper lobe (n =5),lower lobe (n =2) and left upper lobe (n =1).One case was difficult to distinguish because of its huge mass and the remainder was all peripheral.With pseudocapsule (n =4),coarse calcification (n =1),hilar & mediastinal node metastasis (n =2) and cavity (n =1).The manifestations included extensive lung alveolar septal thickening & ground glass (n =1) and massive deep leaf & glitches (n =2).The scans were non-enhanced alone (n =1) and non-enhanced & enhanced (n =7).Six cases had shaped enhancement while another 5 uneven thickness of annular enhancement.And 4 cases had floating-ice change.Primary pulmonary sarcomatoid carcinoma is common in subpleural lung lobe.And the floating-ice sign is valuable in the diagnosis of sarcomatoid carcinoma.