MRI of colorectal cancer liver metastases: comparison of orally administered manganese with intravenously administered gadobenate dimeglumine

Abstract

ObjectivesTo compare the sensitivity of MRI to detect colorectal cancer liver metastases (CRLM) after ingestion of manganese-based contrast agent (CMC-001) with that of a comprehensive intravenous gadobenate dimeglumine protocol, and to assess the safety and acceptability of oral manganese.Methods20 patients suspected of having 1–6 CRLM were included prospectively in this randomised cross-over study. Liver MRI was performed with a one-week interval at 1.5 T and included T1-w VIBE and T2-HASTE, before and after administration of 1.6 g CMC-001 or 0.1 mmol/kg gadobenate dimeglumine. The metastasis-to-liver signal intensity (SI) ratio was calculated. Standard of reference was histopathology after surgery, or combination of other imaging studies and/or follow up. Adverse events (AE) and clinicolaboratory tests were monitored.ResultsOf 44 metastases, 41 were detected after CMC-001 (93%) and 42 after gadobenate dimeglumine (95%). Fifteen false–positive lesions were found after CMC-001 and 2 after gadobenate dimeglumine. The metastasis-to-liver SI ratio was significantly higher after CMC-001 than after gadobenate dimeglumine (0.51 and 0.21 respectively, P < 0.0001). More AE occurred after manganese compared to gadobenate dimeglumine.ConclusionsCMC-001 is as sensitive as an extensive intravenous gadobenate dimeglumine protocol in detecting CRLM. It was relatively well tolerated but had higher rates of gastrointestinal AE.Key Points• Liver MRI after ingestion of manganese is highly sensitive for detecting metastases • High false–positive rate necessitates further evaluation, in some cases • The MR examination time is short • Oral ingestion of manganese seems safe and relatively well tolerated by patients • Manganese compounds may be useful for liver metastasis surveillance after colorectal cancer