Application Value Of MR Amide Proton Transfer Weighted Imaging In Hepatocellular Carcinoma

Objective:To explore the feasibility of predicting microvascular invasion（MVI）,Ki-67expression and histological grade of hepatocellular carcinoma（HCC）by APTw value derived from MR amide proton transfer-weighted（APTw）imaging,and to compare it with diffusion weighted imaging（DWI）.Methods:160 patients with hepatic mass prospectively undergone upper abdominal MRI including APTw and DWI.According to the pathological results,hepatic cell carcinoma was included in the study.The APTw and ADC values of the lesions were measured on APTw and ADC images,respectively.According to the results of immunohistochemical staining,the proportion of positive cells≤10%was defined as low expression of Ki-67 and>10%was defined as high expression of Ki-67.According to the pathological results and Edmonson-Steiner grading standard,hepatocellular carcinoma was divided into four grades:Ⅰ,Ⅱ,ⅢandⅣ.GradeⅠandⅡwere defined as low grade group,and gradeⅢandⅣwere defined as high grade group.Mann-Whitney U test or independent sample t test were used to analyze the differences of APTw and ADC values between MVI positive and negative group,Ki-67 high and low expression groups,high grade and low grade group.Spearman correlation analysis was used to evaluate the correlation between APTw values,ADC values,maximum tumor diameter and Ki-67 labeling index.Furthermore,the receiver operating characteristic curve（ROC）was used to evaluate the efficacy of APTw and ADC values in the differential diagnosis of hepatocellular carcinoma between MVI positive group and negative group,between Ki-67 high and low expression groups,and between high grade and low grade HCC.The difference of diagnostic performance between APTw and ADC values was compared by De Long testResults:Among 160 patients 56 cases of hepatocellular carcinoma were included in this study.The APTw value of MVI positive group（n=27）was higher than that of MVI negative group（n=29）[（1.68±1.02）%vs.（0.21±1.29）%;P<0.001].The ADC value of MVI positive group was lower than that of MVI negative group[（0.84±0.13）×10^-3mm²/sec vs.（0.92±0.17）×10^-3mm ²/sec,P=0.043].The ADC values of Ki-67 high expression group was higher than that of low expression group[1.57（1.06,1.92）%vs.0.16（-0.67,0.72）%,P<0.001],and the ADC values of Ki-67 high expression group was lower than that of low expression group[0.82（0.75,0.90）×10^-3mm²/sec vs.1.01（0.87,1.10）×10^-3mm²sec.P=0.003].There was a positive correlation between APTw values and Ki-67 index expression（ρ=0.493,P<0.001）,and a negative correlation between ADC values and Ki-67 index expression（ρ=-0.274,P<0.041）.The ADC values of high grade group was higher than that of low grade group[（1.54±1.10）%vs.（0.02±1.25）%;P<0.001].There was no significant difference in APT values between the two groups[（0.86±0.16）×10^-3mm²/sec vs.（0.91±0.16）×10^-3mm²/sec;P=0.256].ROC curve analysis showed that the areas under the curve（AUC）of APTw values and ADC values for distinguishing MVI positive and negative groups were 0.815 and 0.649respectively（P<0.05）.The AUC of APTw values and ADC values to differentiate Ki-67 high expression group and low expression group of hepatocellular carcinoma were 0.845 and 0.755 respectively,and there was no significant difference between them（P>0.05）.The AUC of APTw values in differentiating high-grade and low-grade hepatocellular carcinoma was 0.819.Conclusion:APTw imaging is a valuable image marker to non-invasively evaluate the invasiveness of hepatocellular carcinoma before operation.It is helpful to distinguish between MVI positive or negative,Ki-67 high or low expression,high or low grade.,APTw values were positively correlated with the expression of Ki-67.APTw imaging was superior to DWI in assessing the status of MVI and hepatic carcinoma grading.