Can the patient with cirrhosis be imaged for hepatocellular carcinoma without gadolinium?: Comparison of combined T2-weighted, T2*-weighted, and diffusion-weighted MRI with gadolinium-enhanced MRI using liver explantation standard.

PURPOSE: This study aimed to evaluate a non-gadolinium-enhanced magnetic resonance imaging (MRI) protocol including T2-weighted, T2*-weighted, and diffusion-weighted MRI sequences for identifying hepatocellular carcinoma (HCC) with liver explantation as the reference standard. Also, a stand-alone pre- and dynamic post-gadolinium-enhanced liver MRI data set was interpreted from the available patient data for relative comparison purposes. MATERIALS AND METHODS: A retrospective review identified 37 appropriately selected liver transplant patients who had had preoperative MRI. Two data sets were created from the MRI studies: (1) non-gadolinium-enhanced (including T2-weighted, T2*-weighted, and diffusion-weighted sequences) and (2) pre- and dynamic post-gadolinium-enhanced (3-dimensional T1-weighted gradient recalled echo) and were presented to 2 independent, blinded observers. A separate blinded observer assessed the pathologic results from liver explantation to establish the reference standard. RESULTS: On explant pathology, 21 of 37 patients had 31 HCC (mean [SD] largest diameter, 19 [9] cm; range, 7-40 mm). Per-lesion sensitivity of non-gadolinium-enhanced MRI for identifying HCC was 52% (reader 1) and 55% (reader 2), and specificity was 90% (reader 1) and 88% (reader 2). Per-lesion sensitivity of the stand-alone pre- and dynamic post-gadolinium-enhanced MRI was 84% (reader 1) and 81% (reader 2), and specificity was 62% (reader 1) and 65% (reader 2). CONCLUSIONS: Non-gadolinium-enhanced MRI had a moderate sensitivity for HCC but had a high specificity. Although non-gadolinium-enhanced MRI cannot be recommended as a primary imaging approach for HCC, the results demonstrate the contribution of non-gadolinium-enhanced sequences to imaging of HCC. A non-gadolinium-enhanced MRI protocol may have a diagnostic value when gadolinium cannot be administered.

Diagnostic accuracy of diffusion-weighted MRI for identifying hepatocellular carcinoma with liver explant correlation.

BACKGROUND: The goal of this study was to use liver explant correlation to assess the diagnostic accuracy of diffusion-weighted (DW)-MRI for hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Thirty-seven patients were retrospectively identified who had undergone liver transplantation and had preoperative, respiratory-triggered, single-shot echo-planar DW-MRI. Two independent blinded observers evaluated the DW-MRI images for HCC and comparison was made with the explanted specimens. RESULTS: By pathology, 29 HCCs (mean largest diameter 2.0 cm; range 0.7-4.0 cm) were identified in 20 patients. Sensitivity and specificity for reader 1 were 55 and 92%, and for reader 2 were 45 and 100%. There was 'substantial' inter-observer agreement (kappa = 0.64). CONCLUSION: DW-MR is not sensitive enough for HCC to be used as a stand-alone sequence, although its high specificity suggests that it is likely valuable as a component of a liver MRI protocol.

Assessment of the diagnostic accuracy of T2*-weighted MR imaging for identifying hepatocellular carcinoma with liver explant correlation.

BACKGROUND: T2*-weighted MRI may represent a novel method for identifying hepatocellular carcinoma (HCC). The goal of this study was to assess the diagnostic accuracy of T2*-weighted MRI for HCC with liver explant correlation. MATERIALS AND METHODS: A retrospective review identified 25 patients who had undergone liver transplantation with pre-operative T2*-weighted MRI. All patients had Child's-Pugh A (9), B (9), or C (7) liver disease with 13 transplanted for liver dysfunction and 12 for HCC. The T2*-weighted images were interpreted by 2 blinded, independent observers and the results compared with the explanted specimens. Sensitivity and specificity of T2*-weighted MRI for the identification of HCC was assessed. RESULTS: By pathology, 16 HCC (mean largest diameter 2.1 cm; range 0.9-3.6 cm) were identified in 14 patients. Reader 1 had a sensitivity of 69% (95% confidence interval 41-88%) and a specificity of 100% (68-100%). Reader 2 had a sensitivity of 56% (31-79%) and a specificity of 100% (68-100%). There was a very good inter-observer agreement (kappa=0.84). CONCLUSION: T2*-weighted MRI had a moderate sensitivity for identifying HCC but had an excellent specificity. A T2*-weighted MR sequence may be a useful component of a liver MRI protocol due to its high specificity for HCC, and may be particularly useful in patients unable to undergo gadolinium enhanced MRI.