Diagnosis of colorectal hepatic metastases: Contrast-enhanced ultrasonography versus contrast-enhanced computed tomography versus superparamagnetic iron oxide-enhanced magnetic resonance imaging with diffusion-weighted imaging

Purpose To compare the diagnostic accuracy of contrast-enhanced ultrasonography (CE-US), contrast-enhanced CT (CE-CT), and superparamagnetic iron oxide-enhanced MRI (SPIO-MRI) with diffusion-weighted imaging (DWI) in the evaluation of colorectal hepatic metastases. Materials and Methods Thirty-six patients with colorectal cancers were prospectively enrolled and retrospectively evaluated. Of the 86 metastases identified, 16 were confirmed histologically and the remaining 70 were confirmed by follow-up imaging. CE-CT and SPIO-MRI + DWI were independently evaluated by two readers, whereas CE-US was evaluated by consensus reading of two different readers. Area under receiver operating characteristic curve (Az), sensitivities, and positive predictive values (PPVs) were calculated and compared. Results For both readers, SPIO-MRI+DWI had significantly greater Az (0.879 and 0.904) and sensitivity (78% and 87%) for all lesions compared with CE-CT (0.779 and 0.793; 59% and 59%) and CE-US (0.811; 69%), and significantly greater Az (0.783 and 0.837) and sensitivity (56% and 73%) for lesions ≤1 cm compared with CE-CT (0.562 and 0.601; 20% and 22%) and CE-US (0.66; 37%). For lesions >1 cm, there was no significant difference in Az, sensitivity and PPV between all the image sets. Conclusion SPIO-MRI with DWI was the most reliable modality for evaluation of liver metastases particularly for lesions ≤1 cm. J. Magn. Reson. Imaging 2010;32:1132–1140. © 2010 Wiley-Liss, Inc.