Preoperative assessment of liver metastasis originating from colorectal carcinoma: is super paramagnetic iron oxide particles-magnetic resonance imaging (SPIO-MRI) useful for screening?

ABSTRACT

BACKGROUND/AIMS: Recently, early detection of liver tumors has been possible with improvement of various imaging techniques, and practical selection of imaging is clinically necessary to distinguish metastatic liver carcinoma (MLC) from colorectal carcinoma. METHODOLOGY: We retrospectively examined the diagnostic accuracy of enhanced computed tomography (eCT) and super paramagnetic iron oxide particles magnetic resonance imaging (SPIO-MRI) for 110 MLC lesions in 47 patients who underwent hepatic resection at a single Japanese cancer institute between 2000 and 2006. Sensitivity and positive predictive value (PPV) of both imaging techniques in comparison with resected specimens were analyzed. Fourteen cases were synchronous liver metastasis, which were resected simultaneously. RESULTS: On a per patient basis, both eCT and SPIO-MRI showed a sensitivity of 85.1% (40 of 47 patients) and PPV was 100%, respectively. On a per lesion basis, a sensitivity of SPIO-MRI (98/110 lesions; 89%) tended to be higher than that of eCT (92 of 110 lesions; 84%), but not statistically different (p=0.32). PPV of SPIO-MRI (98 of 99 lesions; 99%) was not different from that of eCT (92 of 93; 99%). Twelve lesions in 7 patients that were not detected by both imaging methods were small lesions. PPV for liver cyst and non-timorous lesions was 99% by both imaging methods. Two liver cysts could be clearly diagnosed by SPIO-MRI only. CONCLUSIONS: We found no superiority of diagnosis with SPIO-MRI, which may not be conceptually useful for preoperative screening for MLC from colorectal carcinomas. SPIO-MRI may be useful to detect non-cancerous lesions as an adjuvant diagnostic tool with eCT.