Objective To study the imaging apperances and the diagnostic value of conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in differentiating histopathological types of small hepatocellular carcinoma (sHCC).Methods 40 sHCC confirmed by histopathology were classified into 4 groups according to their degree of differentiation:well (n=6),well-moderate (n=5),moderate (n=27) and moderate-poor (n =2).All patients received conventional MRI and DWI (1.5T,b =0 and 600 s/mm2) before the operation.The ADC values of the sHCC were measured and compared.Results On T1WI,32 lesions showed hypointensity,4 hyperintensity (well) and 4 isointensity (well-moderate =2,moderate =2).On T2WI,hyperintensity was observed in 39 lesions and isointensity in 1 lesion (well).Steatosis in the sHCC was seen in 17 of 40lesions (17/40,42.5 ％,well=4,well-moderate=1 and moderate=12).A pseudocapsule was seen in 67.5 ％ sHCC (27/40,well=4,well-moderate=3,moderate=18 and moderate-poor=2).32 lesions showed hypervascularity on arterial phase,and 8 lesions showed hypovascularity (well=3,moderate =4,moderate-poor=1).On DWI,37 lesions showed hyperintensity,except for 3 lesions with welldifferentiated sHCC which showed isointensity (50％,3/6).The mean ADC values±S.D.of sHCC in the well,well-moderate,moderate and moderate-poor groups were (1.757 ± 0.337) × 10-3,(1.917±0.574)×103,(1.816±0.545)×103 and (1.723±0.217)×10-3,respectively.There were no significant differences among the 4 groups.Conclusion The imaging appearances of wellmoderate,moderate and moderate-poor sHCC on conventional MRI were classical which make diagnosis easy.Hyperintensity on DWI contributed to diagnosis.However,the imaging appearances of some well-differentiated sHCC were atypical.The lesions could be isointensity or hyperintensity on DWI.The combination of conventional MRI and DWI contributed to better diagnosis of sHCC,especial for atypical sHCC.

BACKGROUNDOrthotopic liver transplantation (OLT) has become the therapeutic option of choice for end-stage liver disease. The aim of this study was to investigate the changes of splenic morphology, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), apparent diffusion coefficient (ADC) values and explore their value in evaluating the therapeutic effects of orthotopic liver transplantation (OLT) on portal hypertension at 1.5 Tesla MRI.

METHODSTwenty patients with portal hypertension undergoing OLT were included in this study. Conventional MRI and diffusion-weighted image (DWI) (b value = 600 s/mm(2)) sequences were applied on each patient before and after OLT, and these patients were referred to as the preoperative and postoperative groups. Twenty healthy individuals were selected as the normal group. After image acquisition, the splenic width (W), thickness (T), length (L), the diameter of the portal vein (PD) and splenic vein (SD) were measured and the splenic volume (V) was calculated. The SNR and CNR were measured on T2WI. The ADC maps were calculated using the b600 in DWIs and the ADC values were measured.

RESULTSCompared with the preoperative group, the splenic V, PD and SD decreased significantly in the postoperative group (P < 0.05). All splenic morphological values were significantly different between preoperative and normal groups (P < 0.05). The splenic L and V were significantly different (P < 0.05) between postoperative and normal groups. The SNR and CNR values were 17.66 ± 4.62 and 13.18 ± 3.12, 11.50 ± 1.64 and 7.44 ± 4.32, 4.24 ± 1.24 and 3.03 ± 2.41 in the preoperative, postoperative and normal groups, respectively. Both SNR and CNR decreased after OLT, but they was still higher than the normal values. The SNR was significantly different between any two groups (P < 0.05). The CNR was significantly different (P < 0.05) between the preoperative and postoperative groups, preoperative and normal groups. The splenic ADC values were (1.339 ± 0.482) × 10(-3) mm(2)/s, (1.120 ± 0.254) × 10(-3) mm(2)/s and (0.997 ± 0.447) × 10(-3) mm(2)/s in the preoperative, postoperative and normal groups, respectively. The difference of ADC values were significant (P < 0.05) between the preoperative and postoperative groups, and the preoperative and normal groups.

CONCLUSIONSOLT is an effective method of treatment for portal hypertension. In addition to dramatically decreasing the splenic V, it can also decrease the splenic SNR, CNR and ADC values in patients with portal hypertension. The changes of splenic SNR, CNR and ADC after OLT may be helpful in providing noninvasive supplementary information in assessing the therapeutic effect of OLT on portal hypertension.

Adult ; Aged ; Female ; Humans ; Hypertension, Portal ; diagnosis ; surgery ; Liver Transplantation ; Magnetic Resonance Imaging ; methods ; Male ; Middle Aged ; Retrospective Studies ; Splenomegaly ; diagnosis ; surgery