Manganese-enhanced MRI predicts the histological grade of hepatocellular carcinoma in potential surgical candidates

Abstract

To evaluate the role of manganese-enhanced magnetic resonance (Mn-MRI) in predicting tumour differentiation prior to liver transplant or resection for hepatocellular carcinoma (HCC). The inclusion criteria were patients with HCC who underwent Mn-MRI prior to transplantation or resection from 2001-2008. T1-weighted MRI images were acquired at 0 and 24h after manganese dipyridoxal diphosphate (MnDPDP) intravenous contrast medium and reviewed prospectively. Manganese retention at 24h was correlated with tumour differentiation and disease-free survival. Eighty-six patients underwent Mn-MRI (transplantation 60, resection 26); 114/125 lesions (91%) that were arterialised as evidenced at computed tomography (CT) and had manganese uptake on MRI were HCC. There were 11 false positives (9%) that were regenerative nodules. Ten of fourteen non-manganese-retaining HCC (71%) were poorly differentiated, compared with only 13/114 manganese-retaining HCC (11%) (p<0.0001). Sensitivity, specificity, positive and negative predictive values of non-retention of MnDPDP in predicting poorly differentiated tumours were 0.43, 0.96, 0.71 and 0.88. Median disease-free survival of patients with non-manganese-retaining HCC was less than for patients with manganese-retaining HCC (14±5 months versus 39±3 months, log rank p=0.025). Non-manganese-retaining HCCs are likely to be poorly differentiated and have a poor prognosis. Manganese-enhanced MRI appears to have a role in preoperative assessment of HCC and warrants further evaluation.