Utility of R2* obtained from T2*-weighted imaging in differentiating hepatocellular carcinomas from cavernous hemangiomas of the liver.

PURPOSE:To evaluate the feasibility of applying R2* values to differentiate hepatocellular carcinomas (HCC) from cavernous hemangiomas of the liver (CHL). MATERIALS AND METHODS:This retrospective study was approved by the participating Institutional Review Board and written informed consent for all subjects were obtained. Seventy-three patients with 79 pathologically identified HCCs and 65 patients with 91 clinically or pathologically identified CHLs were enrolled in this study. All subjects underwent a breath-hold multi-echo T2* weighted MR imaging on a 1.5 T clinical MR scanner. R2* values from HCC and CHL groups were compared using the Mann-Whitney non-parametric U test. A cut-off value of R2* was evaluated with receiver operator characteristic (ROC) analysis. RESULTS:The mean R2* value was 23.32 ± 12.23 Hz (95% confidence interval [CI]: 20.58 Hz, 26.06 Hz) for the HCC group, and 3.66 ± 2.37 Hz (95% CI: 3.17 Hz, 4.15 Hz) for the CHL group. The mean R2* value for HCC was significantly higher than that of CHL (p<0.001). A threshold of 9.48 Hz for the minimum R2* value in the diagnosis of HCC resulted in a sensitivity of 96.20% (76 out of 79 patients), and a specificity of 97.80% (89 out of 91 patients). The positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy for HCC were 97.44% (76 out of 78 patients), 96.74% (89 out of 92 patients) and 97.06% (165 out of 170 patients), respectively. The AUC for differentiation between these two groups was 0.994 (95% CI: 0.980, 1.000). CONCLUSIONS:R2* is a significant MRI biomarker to differentiate HCC from CHL with satisfying sensitivity and specificity.