| OBJETIVE: To evaluate the usefulness of postcontrast magnetic resonance imaging with liver specific contrast agent gadobenate dimeglumine(Gd-BOPTA)-enhanced MRI in characterizing the grade of hepatocellular carcinoma(HCC).MATERIALS AND METHODS: This retrospective study reviewed clinical data of 40 patients(a total of 44 lesions) confirmed by pathology for HCC from December 2014 to February 2016. Preoperative Gd-BOPTA enhanced MRI of all these patients were obtained and analyzed, such as measuring signal intensity of lesions(SIles), liver parenchyma around the lesions(SIhep), erector spinae(SImus) and standard deviation of signal intensity of the surrounding noise(SDnoi) on unenhanced T2 WI, unenhanced T1 WI and contrast-enhanced T1WI(in both arterial and hepatobiliary phase), respectively. Contrast-to-noise ratio in each sequence of MRI were separately counted as CNR1((SIles- SIhep)/SDnoi) and CNR2((SIles- SImus)/SDnoi). Patients were pathologically graded according to standard Edmondson-Steiner pathologic grading system and divided into well-differentiated HCC group(3 cases), moderately-differentiated HCC group(26 cases) and poorly-differentiated HCC group(15 cases). Univariate analysis was performed for the related factors in each group, including the age of patients. CNR1 and CNR2 values of patients with different status of hepatic cirrhosis and liver function in each sequence were tested and compared by independent-samples t-test. CNR1 and CNR2 values in each sequence of various differentiated groups were applied to spearman correlation analysis. Receiver operating characteristic(ROC) curves were performed to evaluate the significance in distinguishing moderately-differentiated HCC from poorly-differentiated HCC using CNR1 value of T1 WI in the arterial phase, CNR2 value of T1 WI in the arterial phase and CNR2 value of T1 WI in the hepatobiliary phase, respectively.RESULTS: The average age of the study was 50.77±10.11 years(range from 23 to 73 years)and the average largest diameter was 5.57±3.83 cm( range from 0.7 to 14.5 cm).35 males and 5 females were included with a total of 44 lesions, in which 3 well-differentiated HCCs, 26 moderately-differentiated HCCs and 15 poorly-differentiated HCCs were confirmed.(1) There is no difference of CNR1 and CNR2 values on Gd-BOPTA enhanced MRI among groups of different age, presence of hepatic cirrhosis and hepatic dysfunction.(2) The CNR1 and CNR2 values on T1 WI in the hepatobiliary phase were significantly lower than that on unenhanced T1 WI.(3) The size of lesions, CNR1 value of T1 WI in the arterial phase, CNR2 value of T1 WI in the arterial phase and CNR2 value of T1 WI in the hepatobiliary phase showed an obvious correlation with the degree of differentiation, the correlation coefficients were-0.371,0.435, 0.503 and 0.512, P values were 0.013, 0.003,0.001 and 0.000, respectively.(4) The CNR1 value of T1 WI in the arterial phase, CNR2 value of T1 WI in the arterial phase and CNR2 value of T1 WI in the hepatobiliary phase used to distinguish the moderately-differentiation HCC from poorly-differentiated HCC represented higher diagnostic value with the critical value measured as 9.72, 12.10 and 4.56, respectively. The sensitivity and specificity for identifying the moderately-differentiated HCC from poorly-differentiated HCC were 92.30% versus 46.70%, 96.20% versus 53.30%, and 84.60% versus 60.00%, respectively.CONCLUSION: Gd-BOPTA enhanced liver MRI can be helpful to the pathologic grading of HCC on both qualitative and quantitative analysis, especially the higher lesions signal intensity in hepatobiliary phase compared with erector spinae in the diagnosis of well-differentiated HCC and moderately-differentiated HCC. However, overlaps of Gd-BOPTA enhanced MRI manifestations may even exist among different pathologic grades of HCC. |
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