Clinical and Pathological Attributes of Hepatocellular Carcinoma Showing Lack of Restricted Diffusion on Magnetic Resonance Imaging

Abstract

Objective: To correlate non-restricted diffusion magnetic resonance imaging (MRI) patterns of hepatocellular carcinoma (HCC), with histopathology and clinical outcome.Material and Methods: We retrospectively evaluated pre-treatment MRIs showing non-restricted diffusion HCC lesions (≥1-centimeter), excluding lesions with poor quality/non-available diffusion weighted imaging (DWI). Three radiologists evaluated 37 lesions in 27 patients, for: T1-weighted (T1W)/T2-weighted (T2W) characteristics, arterial enhancement, washout on portal venous/delayed phase, capsular enhancement, intralesional fat component and presence of cirrhosis. Histopathological reports were categorized as: well/moderate/poorly differentiated. Kaplan-Meier survival analysis was calculated for clinical outcome.Results: From a total of 37 lesions, 24 lesions had available pathological grading, which revealed well and moderately differentiated equally (12 lesions each). None of the non-restricted diffusion HCCs were poorly differentiated. Thirty-five of the 37 lesions (94.6%) showed arterial enhancement with washout; 34 lesions (91.9%) were T2W hypo-/isointense, 33 esions (89.2%) were T1W iso-/hyperintense, 19 lesions (51.4%) showed capsular enhancement and 8 lesions (21.6%) had intralesional fat. These findings in the well and moderately differentiated groups were not significantly different (p-value 0.178-1.000). Overall mean-survival was 6.972 years (95% confidence interval (CI); 5.3-8.6). The 1-year, overall survival rate was 83.6% and for 3-years was 67.9%. Mean survival of well and moderately differentiated groups were 6.88 and 7.23 years (95% CI 5.7-8.0 and 4.4-10.1), respectively (p-value=0.319).Conclusion: DWI may help to predict histological grading of HCC and clinical outcome. We found that non-restricted diffusion HCCs were histologically well or moderately differentiated, with no significant difference of imaging findings and survival rates between the two groups. No poorly differentiated lesions were seen in our non-restricted HCC cohort.