Objective To elevate the clini cal value of different MR pulse sequences in the diagnose of anal fistula. Methods Fifteen cases with clinically suspected anal fistula were included in this study. MR pulse sequences included spin echo T 1WI, turbo inversion recovery magnitude (TIRM), fast low-angle shot image (FLASH), non-enhancement and enhancement subtraction and coronary reconstructing. The display rate of internal fistula, extra fistula, and the branch of fistula canales was compared in three kinds of sequences. Results Perianal abscess was found in 1 case. 24 different kinds of anal fistula were revealed in the other 14 patients. Ten of them were complicated with perianal abscess, and 8 of them complicated with complex multi-branch fistula. The display rate of 3D-FLASH sequence was much higher than those of T 1WI and TIRM in all cases. Conclusion 3D-FLASH sequence is a sensitive method to diagnose the anal fistula and it can reduce the examination time.

Pancreatic cystic lesions are being recognized increasingly due to the development of computed tomography and magnetic resonance imaging.Differential diagnosis between pseudocysts and cystic tumors is the key point for pancreatic cystic lesions.Patients with pancreatic pseudocysts generally have a history of acute or chronic pancreatitis,whereas patients with cystic tumors did not have such a history.Some pancreatic cystic lesions did not have typical imaging presentations,and they were difficult to be diagnosed.Pancreatic cystic lesions could be divided into unilocular cysts,microcystic lesions,macrocystic lesions and cysts with a solid component according to the presentations under computed tomography and magnetic resonance imaging.This typing system is helpful for the diagnosis and differential diagnosis of pancreatic cystic tumors,as well as for the guidance of therapy.

Objective To discuss the technique′s characteristics, manifestation, clinical application, and limit in normal and abnormal pediatric airway by using CTVB (CT virtual bronchoscopy) in comparison with FOB (fiberoptic bronchoscopy). Methods Spiral scans were performed by a GE Hispeed spiral scanner in 113 pediatric chests The reformed images of 45 patients were transported to a workstation by which 3 D reconstructions were performed with a software named Navigator and CTVB was generated Results Bronchi were manifested 100% in grades Ⅰ-Ⅲ, 46 7% and 13 3% were revealed in grade Ⅳ and V with CTVB, respectively FOB can only enter grade Ⅰ-Ⅲ bronchi, only 62 2% of the lobar bronchi can be manifested by FOB The findings of CTVB were stenosis ( n =34), occlusion ( n =11), and mass ( n =16) Only 3 radiotransparent foreign bodies and 2 inflammatory emboli were misdiagnosed as tumors, the rest was consistent with FOB Conclusion CTVB is an important supplement to conventional CT, CTVB can detect intraluminal space occupying lesions and occlusions or stenosises caused by all kinds of causes,but lack specificity CTVB can fly through the occlusions or stenosises of the lumen and enter the distal bronchi, thus can make up for the disadvantages of FOB It can′t make the diagnosis independently and must join together the CT primitive the diagram resemble or rebuild the diagram resemble proceeds to synthesize the analysis

Objective To investigate the features of computed tomography (CT) and magnetic resonance imaging (MRI) on pancreatic neuroendocrine tumors (pNENs).Methods The retrospective and descriptive study was adopted.The clinicopathological data of 33 patients with pNENs who were admitted to the Tongji Hospital of Tongji Medical School of Huazhong University of Science and Technology between May 2012 and February 2016 were collected.All the patients underwent plain and enhanced scans of CT and MRI.Observation indicators:(1) overall imaging findings and pathological results of pNENs,(2) imaging findings of functional pNENs,(3) imaging findings of non-functional pNENs.Main analysis indicators included tumor diameter,location,boundary,density,cystic degeneration,enhancement,signal,calcification,with or without pancreaticobiliary duct dilation,with or without surrounding tissues invasion,lymph node and distant organ metastases.Results (1) Overall imaging findings and pathological results of pNENs:of 33 patinets with pNENs,24 underwent CT examination,3 underwent MRI examination and 6 underwent CT and MRI examinations.Tumors of 33 patients were solitary with a diameter of 0.6-16.0 cm.Ten,1,13 and 9 tumors were respectively located at the head of pancreas,uncinate process of pancreas,body of pancreas and tail of pancreas.Thirty-three patients were diagnosed as pNENs by pathological examination,including 20 with functional pNENs (insulinoma) and 13 with non-functional pNENs,and G1,G2 and G3 were respectively detected in 24,7 and 2 patients.The coincidence rate between preoperative CT or MRI examination and pathological examination was 90.9％ (30/33).One,1 and 1 patients were misdiagnosed as pancreatic cancer,enlargement of peripancreatic lymph nodes and duodenal gastrointestinal stromal tumor,respectively.(2) Imaging findings of functional pNENs:tumor diameter of 20 patients with functional pNENs was 0.6-3.0 cm with an average diameter of 1.5 cm.Fòur,10 and 6 tumors were respectively located at the head of pancreas,body of pancreas and tail of pancreas.Of 20 patients with functional pNENs,tumors of 19 patients showed clear boundary and 1 showed unclear boundary,and tumors of 18 patients had uniform density and 2 had uneven density with cystic degeneration,without the occurrence of calcification.Of 20 patients undergoing dynamic enhanced scans,tumors of 19 patients demonstrated obvious enhancement in arterial phase and slightly obvious enhancement or were equal to normal pancreatic tissues in portal vein phase and lag phase,and tumor of 1 patient demonstrated slight enhancement in arterial phase and was equal to or less than normal pancreatic tissues in portal vein phase and lag phase.Tumors in 3 patients undergoing MRI scans were manifested as hypointensity on T1-weighted imaging (T1WI),hyperintensity on T2WI and hyperintensity on DWI (b =1 000 s/m2),with clear imaging.Of 20 patients,1 was accompanied with atrophy of pancreatic tissues at distal tumor,pancreatic duct dilatation,multiple retention cyst and enlargement of lymph nodes around the hepatic artery.(3) Imaging findings of non-functional pNENs:tumor diameter of 13 patients with non-functional pNENs was 1.5-16.0 cm with an average diameter of 5.0 cm.Six,1,3 and 3 tumors were respectively located at the head of pancreas,uncinate process of pancreas,body of pancreas and tail of pancreas.Of 13 patients with non-functional pNENs,tumors of 11 patients showed clear boundary and 2 showed unclear boundary,tumors of 3 patients had uniform density and 10 had uneven density with cystic degeneration,and tumors of 2 patients had calcification.Of 13 patients undergoing dynamic enhanced scans,tumors of 12 patients demonstrated obvious enhancement in arterial phase,continuous enhancement in portal vein phase and lag phase and less obvious enhancement at cystic degeneration area,with marked enlargement of supplying arteries and draining veins in partial tumors.Tumor of 1 patient demonstrated slight enhancement,and its enhancement was slightly less than normal pancreatic tissues in arterial phase,portal vein phase and lag phase,with unclear boundary.Results of MRI scans in 6 patients showed that tumors of 4 patients were manifested as hypointensity on T1WI,slight hyperintensity or mixed signal on T2WI and hyperintensity on DWI (b =1 000 s/m2),and tumors of 2 patients were manifested as hypointensity on T1WI,hypointensity on T2WI and hyperintensity on DWI (b =800 s/m2).Of 13 patients with non-functional pNENs,4 had pancreaticobiliary duct dilation and 7 had local tissues invasion or distant organ metastasis (4 with liver metastasis,1 with peripanereatic lymph node metastasis,1 with liver and peripancreatic lymph node metastases and 1 with liver metastasis combined with splenic venous and arterial invasion),including 1 in G1,4 in G2 and 2 in G3.Of 5 patients with tumor diameter ＞ 5.0 cm,4 were complicated with liver or lymph node metastases.Conclusions CT and MRI features of pNENs have a certain characteristics.For functional pNENs,benign and solid tumor is common,with clear boundary and smaller diameter.For non-functional pNENs,tumor size is bigger and cystic necrosis occurs within the tumor,with various enhancements.

Objective To study the value of magnetic resonance diffusion tensor imaging(MR-DTI) in evaluating the severity of liver cirrhosis.Methods Seventeen patients with Child A liver fibrosis (age=35.0+11.8 years,14 males and 3 females),12 with Child B(age=44.7+14.0 years,5 males and 7 females) and 8 with Child C(age=48.7+7.6 years,3 males and 5 females) were recruited.All patients had clinical data and serum makers in full.Fifty normal controls (age=35.2+14.2,28 males and 22 females) were also recruited.Diffusion tensor imaging(DTI) was performed in all subjects using a GE Propeller HD 1.5T MR scanner by employing a spin echo single-shot EPI(echo planar imaging) sequence.Average diffusion coefficient(DCave) and fractional anisotropy(FA) maps were generated from each P articipants DTI scan using AW 4.2 functool software.All the statistic analysis was performed in SPSS 13.0 , and P value of less than 0.05 was deemed to be significant . Results DCave values were 1.54±0.25 ,1.33±0.18 ,1.02±0.12 ,0.66±0.27 in control group and Child A , B , C respectively , the FA values were 0.46±0.10, 0.42±0.08, 0.56±0.05,0.71±0.41 in control group and Child A, B, C respectively. Significantly low DCave and changed FA in liver fibrosis group were found(P< 0. 05). Among the four groups, significant differences were found in DCave values and FA values(P<0.05) except control group VS Child A group in FA values(P=0.54).Conclusion MR-DTI is relevant to the severity of liver cirrhosis, and may be a useful tool for evaluating the severity of liver cirrhosis.

Objective To investigate the detection rate and diagnostic value of multi-slice spiral CT scan in detecting fish bone impaction in the esophagus.Methods Experimental group: 30 fresh water fish bones from three variety classes were divided into three groups with length of(23.36±0.15), (28.51±0.07) and (30.89±0.10) mm, and diameter of (4.49±0.31), (1.78±0.09) and (0.49±0.07) mm.The fish bones were put into esophagus models in three different types including parallel, perpendicular and oblique.MSCT with axial scan combined with three dimensional reconstruction technique and plain X-ray film (CR and DR) were used to examine the model.The relations of the number and rate of fish bones were compared between MSCT and X-ray film.Clinical group: MSCT imaging were performed in 20 cases proved by esophageal endoscope or clinical operation, among which 11 cases received plain X-ray film (CR and DR), 15 cases received Barium-soaked cotton and 17 cases received endoscope.Paired Chi-square test was used to compare the differences of detection of fishbone by the different ways.Results In experimental group: All the 90 cases(100%) fish bones of three different species were clearly revealed on MSCT image; only 60 cases(66.7%) fish bones were revealed by plain X-ray film(CR and DR).The number and rate of fish bones detected by MSCT was higher than that of plain X-ray film (CR and DR) (X2=28.03, P < 0.01).In clinical group: 20 cases were made right diagnosis by MSCT, and the location and size of fish bone in the esophagus, the surrounding and complications of esophagus could be clearly demonstrated on MSCT image.Two cases detected by plain X-ray film(CR and DR) ;9 cases detected by Barium-soaked cotton;14 cases detected by endoscopy.The number and rate of fish bones detected by MSCT was higher than that of plain Xray film (CR and DR) (X2=7.11, P < 0.05) and Barium-soaked cotton (X2=4.17, P < 0.05).Conclusions The sensitivity and detection rate of fish bone with MSCT was high and could evaluate the surrounding and complications of the esophagus.MSCT could be used as the first examination of impacted fish bones in the esophagus.

Objective Establish rabbit VX2 soft tissue tumor model,and treat it with percutaneous ethanol injection(PEI)under the guidance of magnetic resonance imaging.Make ready for the therapeutic evaluation with functional magnetic resonance imaging. Methods Fifteen healthy New Zealand white rabbits were included in this study.0.2 mL tumor tissue suspensions were injected into the rabbits’posterior limb.14 days later,all rabbits were underwent conventional MRI examination.PET were performed to all the tumors under the guidance of MRI in the next day of the examination.T2 WI was used as guidance and monitoring means.MR com-patible puncture needle with lateral hole was stabed into the lesion center,and inj ected anhydrous ethanol according to the volume of tumors’diameter (1 mL/cm )slowly.the tumors signal characteristics,morphological feature and pathological feature were ob-served pre and post-operation.Results All of the 1 5 rabbits were established soft tissue tumor model successfully;the success rate is 100%.The tumors were oval or round,3-4 cm in diam.MRI scanning showed low signal on T1 WI and high signal on T2 WI be-fore PEI.PEI was performed to all the tumors under the guidance of MR successfully with 3.5 mL ethanol injected into the tumors in average.T2 WI could monitor the ethanol in dispersion and distribution within the tumors clearly.Histologically,tumors were composed of large,uniform,oval/round cells arranged in solid nests which was intensive in the periphery of tumors.Necrosis tissue was apparent in the center of the tumors.10 days after operation,most tissue in the periphery of tumors was coagulative necrosis , only a few tumor cells left.Ranges of necrosis in the tumors center were obviously increased compared with pre-operation.Conclusion Rabbit VX2 tumor of soft tissue model is suitable for the therapeutic evaluation of tumor .It is an animal model which has the characteristic of simple to operate and high rate of suc-cessful.MR T2 WI can monitor the ethanol in dispersion and distribution within the tumors clearly.It is a good guidance and monitoring imaging method of tumor ablation.

Objective To evaluate the image quality and the diagnostic value of low radiation,low dose and isotonic low concentration iodine contrast pulmonary computed tomography angiography (CTPA) protocol in pulmonary embolism.Methods Eighty patients with clinic ally suspected pulmonary embolism and BMI＜28 kg/m2 underwent pulmonary CTA on a 64-MDCT scanner (GE Discovery CT750 HD).Eighty patients were divided into two groups (group A:n=40,80 kV,Auto mA,20 ml 270 mg I/ml,60％FBP+40％ ASIR; group B:n=40,120 kV,Auto mA,40 ml 370 mg I/ml,100％FBP).Image quality was assessed,using a five-point scoring scale.Intraarterial density was measured in the common pulmonary artery trunk,the main right and left pulmonary arteries,lobar arteries,and then the average CT value was calculated.Image quality score,Average CT value,noise,SNR,CNR,CTDIvol and DLP were compared between the two groups using t-test.The occurrence rate of the superior vena cava iodine contrast agent sclerosis artifacts and the positive rate of pulmonary embolism were compared between the two groups,using Chi-square test.Results PE was found in 33 patients (14 in group A,19 in group B),and there was no difference of the positive rate of PE between two groups (35.0％ vs 47.5％,x2=1.289,P＞0.05).Overall 4-6 pulmonary artery branches were clearly displayed in all the cases.The image quality scores for two groups were 3.9±0.6 and 4.0 ± 0.7,respectively.There was no statistical difference between two groups (t=0.632,P＞0.05).The superior vena cava iodine contrast agent sclerosis artifacts were reduced in group A (28 cases vs.36 cases,x 2=10.362,P＜0.01).The average CT value and noise in group A [(426.8 ± 84.8),(14.9 ± 1.5)HU,respectively] was higher than those in group B [(359.4±75.3),(7.4± 1.4)HU,respectively],which was statistically significant(t=3.758,22.848,respectively; P＜0.01).However,the SNR (28.8 ±6.3)and CNR (24.5±6.1) in group A were lower than those in group B(SNR 50.4± 14.7,CNR 42.9± 13.8).There was statistically significant difference between two groups (t=8.522,7.669,respectively; P＜0.01 both).The CTDIvol[(3.3±0.3)mGy]and DLP[(101.4± 11.9)mGy· cm] in group A were significantly lower than those in group B [CTDI vol (9.6±0.6)mGy,DLP (328.5 ± 37.3)mGy· cm].The difference between two groups was statistically significant(t=56.393,36.675,respectively,P＜0.01 both).Conclusions The low radiation,low dose and isotonic low concentration iodine contrast CTPA protocol shows pulmonary artery branches of 4-6 levels,reduces radiation exposure and contrast media volume compared with the conventional pulmonary CTA,and achieves the same positive rate of PE in comparison of the conventional CTPA.It can meet the clinical needs.

Objective To explore the utility of ADC histogram analysisin differentiation of clear cell renal cell carcinoma(ccRCC)and non-clear cell renal cell carcinoma(non-ccRCC)with r-Fov DWI. Methods Sixty-six renal tumors(46 patients with 47 ccRCCs and 18 patients with 19 non-ccRCCs)in 64 patients, who underwent preoperative routine renal MRI sequences and r-FOV DWI, were retrospectively evaluated. The whole-lesion ADC values derived from histogram anlysis(including ADC mean, ADC median, ADC_5th, ADC_25th, ADC_75th, ADC_95th, skew and kurtosis)were measured for each patient. All parameters between ccRCC and non-ccRCC were compared by using the Student's t test or Mann-Whitney U test. ROC analysis was used to assess the diagnostic performance of ADC histogram in distinguishing the two groups. Results The postive skewness of ADC histograms were mostly seen in the non-ccRCC group, while the negtative skewness were present in the majority of ccRCCs. The skewness was significantly higher in non-ccRCCs than those of ccRCCs(P<0.05). Mean ADC, median ADC, 5th percentile ADC, 25th percentile ADC, 75th percentile ADC and 95th percentile ADC(all P<0.05)were significantly lower in non-ccRCC . There was no significant difference of Kurtosis between two groups(P>0.05). 75th percentile ADC achieved the highest AUC(0.987)in differentiating ccRCC and non-ccRCC, whena cutoff value was 1.81× 10-3 mm2/s. The sensitivity and specificity were 100.0％and 94.7％. Conclusion ADC histograms of r-FOV DWI may be helpful to differentiate ccRCC from non-ccRCC, and the diagnostic accuracy of 75th percentile ADC is highest.

Objective MRI manifestations of infiltrative renal pelvis carcinoma were analyzed and evaluated,to improve its diagnostic accuracy. Methods MRI features of 21 cases of infiltrative renal pelvis carcinoma confirmed pathologically were analyzed retrospectively.All patients underwent plain MRI scan and DWI examination,3 cases underwent PWI examination.Results The center of lesions for all cases were located in the renal collection system,with no change of the renal contour.Most lesions were presented as low signal intensity on T1 WI and slightly low signal intensity on T2 WI,and heterogeneous signal intensity were showed on T1 WI and T2 WI in 5 cases.All lesions were presented as high signal intensity on DWI.After contrast enhancement,mild and moderate enhanced lesions were demonstrated in 3 cases.Renal arteries were wrapped by renal pelvis carcinoma on renal AMRA in 3 cases.4 patients were accompanied with venous tumor thrombus and 1 1 patients with retroperitoneal lymph node metastasis.Adrenal gland metastases were showed in 3 cases.1 case was accompanied with ureter urothelial carcinoma,and 2 cases with bladder carcinomas.Conclusion MRI has a multi-parameter imaging capability and high resolution of soft tissue,and can clearly show the boundary of lesions and surroundings.MRI plays an important role in the diagnosis and differential diagnosis of infiltrative renal pelvis carcinoma.