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

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 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 MRI features of hepatic neuroendocrine tumors (NET G1,G2) and neuroendocrine carcinomas (NEC G3),as well as to improve the accuracy in hierarchical diagnosis.Methods Twenty patients with histopathologically proven NET and nineteen patients with histopathologically proven NEC were retrospectively analyzed.The morphological and MR signal features were compared.Results The morphological features of vascular invasion (P ＜ 0.05) and lymphadenectasis or necrosis (P ＜ 0.05),as well as the MR signal features on portal phase (P ＜ 0.05) and delayed phase (P ＜0.05) were different between the NET group and the NEC group;contrast to noise ratios (CNR) were also different between the two groups (x2 =5.14,P ＜ 0.05),CNR of the NEC group on both arterial phase (Z =121.75,P ＜ 0.05) and portal phase (Z =139.31,P ＜ 0.05) were significantly lower than the NET group;ROC analysis of CNR demonstrated an area under the curve of 0.729 (P ＜ 0.05) on portal phase,when the optimal cut-off value of-61.38 was used,a sensitivity of 90.0％ and a specificity of 63.2％ can be achieved.Conclusions MRI plays an important role in the hierarchical diagnosis of hepatic neuroendocrine neoplasms.The signs of vascular invasion,lymphadenectasis or necrosis as well as the MR signal features during dynamic enhanced scanning are of great value in differentiating NETs from NECs.

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 evaluate the relationship between the T1 relaxation times using gadoxetic acid-enhanced MRI with the organic anion transporter (OATP) and multi-drug resistance protein (MRP) values on colorectal liver metastasis and around normal liver parenchyma.Methods The perspective study included in fifteen patients with liver metastasis from colorectal cancer,who were confirmed colorectal cancer by colonoscopy,liver metastasis by CT scanning and would be underwent liver metastasis surgery.The lesion on the 15 patients was all single.The patients were performed plain scanning,diffusion weighted imaging and dynamic enhancement MRI examination using gadoxetic acid.Besides,for T1 mapping,a dual flip angle three-dimensional gradient echo sequence was performed before and at 20 minutes after gadoxetic acid administration.The reduction rate of T1 relaxation time (ΔT) (before and after gadoxetic-acid administration) of colorectal liver metastasis and around normal liver parenchyma was calculated.The specimens of hepatic metastases and around normal liver parenchyma were obtained during the colorectal liver metastasis operation.After that,they were analyzed by Western-blot and the values on OATP1,OATP8 and MRP2,MRP3 were recorded.The values on OATP1,OATP8 and MRP2,MRP3 and ΔT on hepatic metastases and around normal liver parenchyma were compared with t analysis.The correlation between the sum of the values (hepatic metastases adding around normal liver parenchyma) on OATPI,OATPS,MRP2,MRP3 with T1 relaxation times were calculated by Spearman.Results The scanning images on colorectal liver metastasis using gadoxetic acid MRI examination were as follows:relatively low signal intensity on T1WI; relatively higher signal intensity on T2WI; showing surrounding moderate enhancement on arterial phase and low signal intensity on portal venous phase,delay phase and hepatobililary phase.The values on OATP1,OATP8,MRP2,MRP3 and AT on the hepatic metastases were(0.21±0.09),(0.34±0.21),(0.41±0.22),(0.26±0.14)ng/ml and (33±9)％,respectively.The values on OATP1,OATP8,MRP2,MRP3 and ΔT around normal liver parenchyma were (0.46±0.24),(0.67±0.35),(0.22±0.13),(0.13±0.06) ng/ml and(68±9)％ (t values were 36.37,58.89,24.56,22.52 and 57.16;P＜0.05).The values on patients on OATP1,OATP8,MRP2 and MRP3 [(0.67±0.31),(1.00±0.37),(0.63±0.23),(0.40±0.13)ng/ml,respectively] showed relationship with the values on patients on ΔT(51±9)％ (r values were 0.491,0.432,-0.414 and-0.371;P values were 0.006,0.017,0.023 and 0.040).Conclusion The sum of the values (the hepatic metastases adding around normal liver parenchyma) on OATP1,OATP8,MRP2 and MRP3 showed correlation with the sum of values on the ΔT using gadoxetie acid-enhanced MRI examination,which explained relationship with the quantity of gadoxetic acid absorbed by hepatocyte and the T1 relaxation time on molecular level.

Objective To investigate the MRI features of hepatic IgG4?related inflammatory pseudotumor (IPT). Methods Nine patients with 11 histopathologically proven IgG4?related hepatic IPTs were retrospectively analyzed. The clinical, morphological and MRI signal features on T1WI, T2WI, dynamic?enhanced, and diffusion?weighted imaging were assessed in detail and correlated with pathological findings. The paired t test was used to compare the ADC values of the tumors and the hepatic tissue. Results Hepatic IgG4?related IPT displayed certain MRI features. The dominant lesions were subcapsularly distributed (n=7) with a clear boundary (n=8), which typically showed hypointensity on T1WI (n=11), mild hyperintensity on T2WI (n=8), progressive (n=5) or persistent (n=4) enhancement pattern. Accompanied signs included delayed capsule?like enhancement (n=6) and central nonenhanced areas (n=7). Two lesions showed atypical wash?out pattern with iso or hypointensity on portal and delayed phases. In diffusion weighted imaging, all lesions were hyperintense, and the mean ADC value of the lesions [(1.42 ± 0.36) × 10?3mm2/s] was mildly lower than that of surrounding liver [(1.55±0.31)×10?3mm2/s], although no statistical differences were found(t=0.78, P=0.46). Conclusions Hepatic IgG4?related IPTs display various MRI manifestations. The lesions normally show progressive enhancement pattern with diffuse homogeneous or heterogeneous hyperintensity, accompanied by delayed capsule?like enhancement and central nonenhanced areas.

Objective To explore the effect on image quality and scanning time by changing parameters and using different scan-ning technique for the clinical application of axial FLAIR pulse sequence.Methods Seven different sets of parameters of T2-FLAIR Pulse Sequences were performed on thirty patients at a 3.0 T MR scanner.Group A was scanned with a routine sequence for refer-ence.Group B,reducing the matrix to 128.Group C,increasing the turbo factor parameter to 24.Group D,setting the contatena-tion to 1.Group E setting the Accel.factor PE to 4.Group F,using a BLADE-FLAIR sequence.Group G,using a HASTE-FLAIR sequence.The SNRs of all images were statistically analyzed by ANOVA among 7 sequences.The image quality of all images was statistically analyzed by Kruskal-Wallis test among 7 sequences.Results The SNR of seven groups of images were 54.69 ±8.12, 1 57.57±25.61,44.56±7.37,38.48 ± 9.32,44.1 9 ±8.79,45.60 ± 6.92,105.20 ± 18.25,respectively(F = 266.368,P =0.000). The scores of image quality were 3.87±0.09,2.50±0.12,3.72±0.1 6,3.10±0.10,1.88±0.10,3.92±0.07,2.08±0.10,re-spectively and the differences among groups were statistically significant(χ2 =1 93.361,P =0.000).Conclusion Suitable turto factor and BLADE technique can be the best option for FLAIR sequence in the head.HASTE-FLAIR sequence can act as the secondary op-tion for the uncooperative patients.

Objective To improve the purifying method of Jo-1 antigen from rabbit thymus used for detection of anti-Jo-1 antibody by dot-blotting immunoassay(DB).Methods The rabbit thymus glands were cut into pieces,homogenized and extracted by PBS.Total protein was precipitated by acetone to get acetone powder(RTAP).The RTAP was solved in PBS and separated by an by anti-Jo-1 IgG affinity column.Results 5～7 g RTAP was obtained from 100g rabbit thymus glands.There was 19%～24% of protein in RTAP.Jo-1 antigen was enriched around 1900 folds through affinity chromatography,with 2.5% recovery of antigenic activity.In this preparation,there were several bands on SDS-PAGE,but only one band about 50 ku,reacted with anti-Jo-1 antisera on immunoblotting.Dot-blotting also showed that the antigen only reacted with Jo-1 antisera.The purified Jo-1 antigen was not stable for long time,but the antigenic activity could maintain for a long time when there was MgCl2 in the solution.Conclusion Affinity chromatography was a simple and easy method for purifying Jo-1 antigen from rabbit thymus.The antigen purified by affinity chromatography could meet the requirement for detecting Jo-1 antibody bydot-blotting.

Objective To investigate imaging characteristics of multistep hepatocarcinogenesis in cirrhotic livers on susceptibility-weighted imaging (SWI).Methods Seventy-three patients with 83 nodules in cirrhotic livers underwent hepatic MR imaging with SWI.Two radiologists reviewed MR images by consensus.Imaging characteristics of dysplastic nodules (DN),DN with malignant foci and hepatocellular carcinoma (HCC) were evaluated.Prussian blue staining was performed for semiquantification of hepatic iron content and above cirrhosis-associated nodules.Results Positive iron staining of background liver parenchyma was found in 69 of 73 patients and 4 HCC patients showed iron-negative staining of background liver parenchyma.Nine DNs appeared as hypointensity or isointensity with pathologically confirmed similar (n =7) or slightly decreased (n =2) iron deposition compared with background liver parenchyma.SWI detected 14 of 15 DNs with malignant foci.Seven patients appeared as homogeneous hyperintensity and 1 patient appeared as heterogeneous hyperintensity due to intratumoral hemorrhages.The remaining 6 patients demonstrated as nodule-in-nodule appearance with iron deposition in all background nodules,iron deposition with grade 1 in one internal HCC foci,and iron-free in 5 internal HCC foci.The remaining 50 patients with hepatic iron deposition had 55 HCC lesions.Three HCC lesions had iron deposition with grade 1 to 2 and the remaining 52 HCC lesions were pathologically iron-resistant.HCC appeared as hyperintensity compared with siderotic surrounding liver parenchyma.However,HCCs with diameter larger than 3 cm usually demonstrated heterogeneous hyperintensity due to intratumoral hemorrhage.Conclusions SWI could accurately demonstrate dynamic iron depletion on multistep hepatocarcinogenesis in cirrhotic livers.On SWI images,DNs appear as hypointensity due to siderosis and malignant nodules appear as hyperintensity due to iron depletion.