Purpose: To evaluate the T1 effect of superparamagnetic iron oxide (SPIO) in MR imaging of focal hepatic lesions.
Methods: 21 patients with 34 liver lesions (18 benign) were examined before and immediately after infusion of SPIO particles (Endorem) with a T1-weighted GRE- and SE sequence and a double echo SE sequence at 1.5T. Changes of lesion signal intensity and contrast-to-noise (C/N) ratio were measured in addition to a qualitative analysis of changes in liver vessel signal.
Results: In all cases a marked increase of liver vessel signal intensity was observed on T1-weighted images after SPIO infusion. In contrast to malignant lesions, haemangiomas and adenomas showed significant signal changes (p < 0.05) on T1-and T2-weighted images. Highest signal changes were achieved for haemangiomas on T1-GRE images (+80%) followed by T1-SE (+41%) and T2-SE (-42%). Malignant liver lesions exhibited highest C/Ns on T2-weighted postcontrast images.
Conclusion: The T1-effect of Endorem offers no benefits in respect of detectability of malignant liver lesions. However, it is helpful in characterising haemangiomas and their differentiation from liver tumours.