Objective To discuss the diagnostic value of CT and MRI for primary anorectal malignant melanoma(AMM).Methods 5 patients(2 males and 3 females)with AMM confirmed pathologically were analyzed retrospectively,which were examined by CT(n=4)and 1.5T MRI(n=1).Results AMM presented as bulky intraluminal fungating masses without intestinal obstruction(n=4)and irregular rectal wall thickening(n=1).2 cases had perirectal fat infiltration and extended to the presacral space in one case,4 cases had perirectal enlarged lymph nodes and larger than 3 cm in diameter in one case.Nonenhanced CT showed a hypodense lesion and contrast-enhanced CT showed slight enhancement(n=1)and mild enhancement(n=3).The tumor scanned by MRI depicted high intensity on T1WI and low intensity on T2WI,so did the enlarged lymph nodes and bone metastasis.Fat-saturation T1WI significantly improved the extention of tumor and detection of metastasis.Conclusion Bulky intraluminal fungating masses without intestinal obstruction,perirectal fat infiltration and enlarged lymph nodes may be helpful to diagnose AMM.MRI is especially useful in differentiating melanotic AMM from other rectal tumors.

Objective To analyze the value of CT in diagnosing and following-up gastrointestinal stromal tumors(GIST).Methods 117patients with CT examination and histological diagnosis of GIST were retrospectively reviewed.Results 117 patients had 118 GIST.Thelocations of primary tumor were as follows: stomach(n=56),small intestine(n=40),esophagus(n=6),colorectum(n=6),mesentery(n=3),retroperitoneum(n=2) and indefinite origin(n=5).Size of tumor was 1.7~18 cm.Tumors(5 cm) often demonstrated lobulated shape with central low attenuation area and heterogeneous enhancement.There were 17 tumors with bubble,13 with scattered calcifications,12 with metastases of liver.With following-up,23 of 37 were developed local recurrence or hepatic metastases.Conclusion CT is aneffective and useful imaging modality in the diagnosis and follow-up gastrointestinal stromal tumors.

Objectives To analyse the radiological features of dynamic MRI and diffusion weighted imaging for atypical small hepatic hemangiomas (≤2 cm).Methods The MR images of 14 patients with 14 pathologically-confirmed small atypical hepatic hemangiomas were retrospectively analyzed.All these patients underwent MR imaging including plain T1 weighted imaging,T2 weighted imaging,dynamic contrast enhanced scanning,and diffusion weighted imaging.The signal-to-noise ratios of hemangiomas,the portal vein and the aorta,lesion-to-liver contrast-to-noise ratios,ADCs of hemangiomas and the liver,lesion-to-liver signal ratios in DWI were assessed to generalize the MRI features and the key points in differential diagnosis of this type of hepatic hemangioma.Results In dynamic contrast enhanced scanning,the atypical hemangiomas were barely enhanced and they were hypointense most of the time.The lesions might show a faint enhancement in the delayed phase.There were significant differences in the changes in signal-to-noise ratio between hemangiomas and aorta as well as portal vein in all the three phases (P＜0.05).In DWI,the signal intensities and ADCs of the hemangiomas were higher than the liver parenchyma (P＜0.01).Conclusions MRI dynamic contrast enhanced scanning,diffusion weighted imaging and evaluation of the ADCs were important in the diagnosis and differential diagnosis of small atypical hepatic hemangiomas.

ObjectiveTo explore the best measurement of waist circumference related with intra-abdominal fat volume evaluated by CT scan.MethodsHeight,weight,and hip circumference were measured among 147 subjects aged over 18 years old.Waist circumference was measured at 3 different levels:the upper brim of the iliac crest ( WC1 ),the midpoint between costal brim and iliac crest ( WC2 ),and the umbilicus ( WC3 ).The intra-abdominal fat volume was evaluated by CT scan.ResultsIntra-abdominal fat volume was significantly higher in men than in women [ ( 1 236.0±608.4 vs 931.0±665.0)cm3,P＜0.01 ].Correlation analysis showed that WC1 ( r =0.634),WC2( r=0.677),and WC3 (r =0.712)were positively correlated with intra-abdominal fat volume ( all P＜0.01 ).Partial correlation analysis adjusted by gender,weight,or body mass index showed that the correlation of intra-abdominal fat volume with WC3 ( r were 0.488 and 0.432) was better than that with WC1( r were 0.347 and 0.293 ) and WC2 ( r were 0.424 and 0.365 ).Multiple linear stepwise regression analysis demonstrated that WC2 and WC3 were independently associated with intra-abdominal fat volume and WC3 was the strongest impact factor (β =0.270,R2c =0.504,P＜0.01 ).ConclusionsWaist circumference is a simple anthropometric measurement parameter reflecting the degree of intraabdominal fat accumulation.All three different measurements of waist circumference may reflect intra-abdominal fat volume,while waist circumference at umbilical level is the best among them.

Objective To evaluate the difference of image quality and lesion detection between Gd+-EOB-DTPA with Gd+-DTPA-enhanced MRI in cases of hepatocellular carcinoma (HCC).Methods A total of 21 HCC patients underwent both Gd+-EOB-DTPA and Gd+-DTPA-enhanced MRI examination,comparing the difference between the two agents using the value of lesion display quality index,sensitivity,specificity,positive and negative predictive value,diagnosis accuracy and CNR.Results There were 25 lesions on the 21 HCC patients with 9 lesions ＜ 1.0 cm.24 lesions showed hypointensity and 1 lesion showed isointensity on hepatobiliary phase with Gd+-EOB-DTPA-enhanced MRI.15 lesions showed hypointensity,5 lesions showed isointensity and 5 lesions showed hyperintensity on portal venous phase with Gd+-DTPA-enhanced MRI.The value of lesion (in particular for the lesion ＜ 1.0 cm)display quality index,sensitivity,specificity,positive and negative predictive value,diagnosis accuracy on Gd+-EOB-DTPA-enhanced MRI and Gd+-DTPA-enhanced MRI were 17scors,89％,89％,89％,89％ and 12 scors,33％,33％,33％,67％ respectively.CNR on hepatobiliary phase with Gd+-EOB-DTPA-enhanced MRI was 639.35.CNR on arterial phase and portal venous phase with Gd+-DTPA-enhanced MRI were 225.25 and 93.25 respectively.The data showed that Gd+-EOB-DTPA-enhanced MRI was better than that of Gd+-DTPA-enhanced MRI.Conclusions Gd+-EOB-DTPA-enhanced MRI displays lesions (especially for lesions ＜ 1.0 cm) better compared with Gd+-DTPA-enhanced MRI increasing the diagnostic accuracy of small HCC.

Objective To compare the MR features of small hepatocellular carcinoma (sHCC) and small intrahepatic mass-forming cholangiocarcinoma (sIMCC) (≤ 3 cm) and improve the accuracy in diagnosis.Methods Imaging studies of 318 patients with 351 sHCCs and 42 patients with 47 sIMCCs were retrospectively reviewed.Signal intensity on T2WI and on each phase of dynamic enhanced imaging,enhancement patterns,and accompanying findings of the two groups were compared by qualitative and quantitative studies.The qualitative imaging features of tumors were compared by the x2 test and the Fisher exact test,and the statistically significant variables obtained from univariate analysis were used to conduct multivariate stepwise logistic regression analysis.Enhancement pattern between sHCCs with elevated AFP and normal AFP were assessed by thex2 test.Results Multivariate analysis indicated that signal features of enhancement pattern and the accompanying findings of tumor capsule and hepatic capsule retraction were key predictors in differentiating sHCC from sIMCC:Wash-out pattern (276/351) with enhanced tumor capsule (275/351) highly indicated sHCC,while progressive enhancement pattern (27/47) with hepatic capsule retraction (8/47) indicated the diagnosis of sIMCC (P ＜ 0.01).Compared with sHCC with normal AFP,atypical patterns as progressive (n =4) and stable enhancement (n =32) were more commonIy seen in lesions with elevated AFP,dynamic enhancement pattern was different between the two subgroups (x2 =8.241,P ＜ 0.05).Conclusions Enhancement patterns and the accompanying tumor capsule and hepatic capsule retraction were the most important predictors in differentiating sHCC from sIMCC.In addition,enhancement pattern was relatively more typical in sHCCs with normal AFP which provided valuable information in diagnosis for clinicians.

Objective To describe the characteristic MR appearances in hepatocellular carcinoma after radiofrequency ablation (RFA) during follow-up studies. Methods MR images of 110 patients with hepatocellular carcinoma after RFA ,which were categorized into 3 MR examination intervals ( ≤48 h, 1-6 m, ＞6 m), were analyzed retrospectively. The sequential changes of MR images were assessed and compared using Chi-square test. Results All RFA areas of 110 patients typically exhibited hyperintensity on GRE-T1 WI and hypointensity on TSE-T2 WI with fat suppression within 48 h after ablation. Subsequently,the signal intensities of the RFA areas decreased on GRE-T1 WI which showed significant differences after 6 months( P ＜0. 015 ). On GRE-T1 WI , RFA lesions were hyperintense in 72, iso-or hypo-intense in 4 at 1-6 months and hyperintense in 60, iso-or hypo-intense in 17 after 6 months. On TSE-T2 WI, 65 RFA lesions were hypointense, 11 isointense at 1-6 months and 47 were hypointense, 30 isointense after 6 months. The increased intensity on TSE-T2 WI showed significant differences after 6 months( P ＜ 0. 015 ).On contrast-enhanced MR images, RFA lesions showed peripheral rim of enhancement within 48 h and exhibited a tendency to show no enhancement ( n = 37 at 16 months and n = 63 after 6 months ) with significant differences between MR examination intervals( P ＜ 0. 015 ). In 6 patients with residual tumor or local tumor progression, nodular lesions were found at the periphery of the RFA. These nodular lesions showed moderate to marked enhancement as well as hypointense signal on GRE-T1WI, and moderate hyperintense signal on TSE-T2WI. Conclusion MR imaging could depict the characteristics of coagulative necrosis of tumor, residual tumor or local tumor progression in patients with hepatocellular carcinoma after RFA therapy.

Objective To evaluate the value of multi-slice CT(MSCT)classification in the assessment of the hilar cholangiocarcinoma resectahility.Methods Thirty patients with surgically and histopathologically proved hilar cholangiocarcinomas who underwent preoperative MSCT and were diagnosed correctly were included in present study.Transverse images and reconstructed MPR images were reviewed for Bismuth-Corlette classification and morphological classification of hilar cholangiocarcinoma.Thcn MSCT classification was compared with findings of surgery and histopathology.Curative resectabilty of different types according to Bismuth-Corlette classification and morphological classification were analyzed with chi-square test.Results In 30 cases,the numbers of Type Ⅰ,Ⅱ,Ⅲa,Ⅲb and Ⅳ according to BismuthCorlette classification were 1,3,4,5 and 17.Seventeen patients underwent curative resections,among which 1,2,1,4 and 9 belonged to Type Ⅰ,Ⅱ,Ⅲa,Ⅲb and Ⅳ respectively.However,there was no significant difference in curative resectability among different types of Bismuth-Corlette classification(X2=0.9875.P＞0.05).In present study,the accuracy of MSCT in Bismuth-Corlette classification reached 86.7%(26/30).The numbers of periducatal infiltrating,mass forming and intraductal growing type were 13,13 and 4,while 6,8 and 3 cases of each type underwent curative resections.There was no significant difference in curative resectability among different types of morphological classification(X2=1.2583,P＞0.05).The accuracy of MSCT in morphological classification was 100%(30/30)in this study group.Conclusion MSCT can make accurate diagnosis of Bismuth-Corlette classification and morphological classification.which is helpful in preoperative respectability assessment of hilar cholangiocarcinoma.

Objective To investigate the value of MR perfusion parameters and ADC in the diagnosis of pancreatic cancer and pancreatic mass at 3.0 T MR. Methods Twenty healthy volunteers and 25 patients with pancreatic cancers proven by pathological results underwent MR PWI at a 3.0 T scanner. A two-compartment model was used to quantify Ktrans, Kep and Ve in the pancreatic cancer, adjacent pancreatic tissue, distal inflammatory pancreatic tissue and normal pancreatic tissue. All parameters among different tissues were analyzed and compared with ANONA. Fifteen normal volunteers and 58 patients, including 30 patients with pancreatic cancer (proven histopathologically), 9 patients with pancreatitis pseudotumor (4 patients proven by histopathological results, 5 patients proven by follow-up after treatment), 9 patients with solid pseudopapillary tumor of pancreas (SPTP, proven histopathologically) and 10 patients with pancreatic neuroendocrine tumor (PET, proven by histopathology), underwent respiratory-triggered DWI on 3.0 T. ADC values of normal pancreas and all types of pancreatic lesions were statistically analyzed and compared with ANONA. ROC curve was used to analyze the diagnostic power of ADC value. Results Ktrans of pancreatic cancer, adjacent pancreatic tissue, distal inflammatory pancreatic tissue and normal pancreatic tissue were (1.66±1.25), (3.77±2.67),(1.16±0.94) and (2.69±1.46)/min respectively(F=8.160, P＜0.01). LSD test showed that Ktrans in the pancreatic cancer was statistically lower than that in normal pancreas (P=0.011)and adjacent pancreatic tissue(P=0.002). Kep of pancreatic cancer, adjacent pancreatic tissue, distal inflammatory pancreatic tissue and normal pancreatic tissue were (2.53±1.55), (5.64±2.64), (1.70±0.91) and (4.28±1.64)/min respectively(F=4.544, P＜0.01). LSD test revealed that Kep in pancreatic cancer was statistically lower than that in normal pancreatic tissue (P=0.035)and adjacent pancreatic tissue(P=0.041). The median of Ve among the pancreatic cancer, adjacent pancreatic tissue, distal inflammatory pancreatic tissue and normal pancreatic tissue were 0.926, 0.839, 0.798 and 0.659 respectively (χ2=12.040,P＜0.01). Ve in pancreatic cancer was statistically higher than that in normal pancreatic tissue (P=0.002). ADC values of the pancreatic cancer, pancreatitis pseudotumor, SPTP, PET and normal pancreas were(1.57±0.26)×10-3,(1.19±0.15)×10-3,(1.05±0.35)×10-3,(1.62±0.41)×10-3 and (1.82±0.25)×10-3 mm2/s(F=21.681, P＜0.01). LSD test showed there were significant statistical differences in ADC values among pancreatic cancer, pancreatitis pseudotumor and normal pancreatic tissue (P＜0.01). ROC curve disclosed that the sensitivity, specificity, positive predictive value and negative predictive value were 86.7%, 88.9%, 96.3% and 66.7% respectively, when ADC≥1.33×10-3 mm2/s was used as a cutoff value for differential diagnosis of PDCA from MLP. The sensitivity, specificity, positive predictive value and negative predictive value were 77.8%, 100.0%, 100.0% and 83.3% respectively when ADC≤1.25×10-3 mm2/s was used as a cutoff value for differential diagnosis of SPTP from PET. Conclusion Compared to normal pancreatic tissue, pancreatic cancer usually had a lower Ktrans, Kep and larger Ve. ADC values from respiratory-triggered DWI were well related to histopathological features of pancreatic entities and may be helpful in the differential diagnosis.

Gadolinium DTPA ; Humans ; Magnetic Resonance Imaging ; Non-alcoholic Fatty Liver Disease