Efficacy of SPIO-MR Imaging in the Diagnosis of Liver Metastases from Colorectal Carcinomas

Abstract

Aim: To determine whether superparamagnetic iron oxide-enhanced magnetic resonance imaging (SPIO-MRI) could replace intravenous contrast-enhanced spiral CT (iv-CT) and spiral CT during arterial portography (CTAP) combined with spiral CT hepatic angiography (CTHA) in the diagnosis of liver metastases from colorectal carcinomas. Methods: Twenty-six adult patients with liver metastases were studied preoperatively by means of iv-CT, CTAP/CTHA, and SPIO-MRI. Preoperative diagnoses using iv-CT, CTAP/CTHA, and SPIO-MRI were compared with intraoperative and pathological findings in resected specimens. The gold standard for the lesions that were resected was histological examination. Intraoperative findings represented the gold standard for lesions that were not resected. Results: Twenty-six patients were found to have a total number of 43 liver metastases. The sensitivities of iv-CT, CTAP/CTHA, and SPIO-MRI were 74.4, 100, and 90.7%, respectively. SPIO-MRI was significantly superior to iv-CT (p < 0.05). The positive predictive values of iv-CT, CTAP/CTHA, and SPIO-MRI were 97.0, 91.5, and 100%, respectively. CTAP/CTHA yielded four false-positive lesions. In contrast, we detected no false-positive findings using SPIO-MRI. Conclusions: These results suggest that SPIO-MRI might not completely replace CTAP/CTHA, but could replace iv-CT in the diagnosis of liver metastases from colorectal carcinomas. It is thought that SPIO-MRI is a promising imaging modality for diagnosing liver metastases in patients with colorectal carcinoma because of its relatively high sensitivity and extremely high specificity.