EFFECTS OF AMI-25 ON LIVER VESSELS AND TUMORS ON T1-WEIGHTED TURBO-FIELD-ECHO IMAGES - IMPLICATIONS FOR TUMOR CHARACTERIZATION

This study was devoted to tumor differentiation in liver MR T1-weighte d imaging with superparamagnetic iron oxide (SPIO), Twenty-one patient s with 40 liver lesions were studied at 1.5 T. Before and at least 45 minutes after SP1O administration, turbo-field-echo (TFE) T1-weighted, TFE T1 x T2-weighted (MXT), and fat-suppressed turbo-spin-echo Ta-we ighted images were acquired, A quantitative analysis was performed bli ndly. On TFE T1-weighted images, the signal enhancement was -33% +/- 1 2 for the liver, -24% +/- 2 for adenomas and focal nodular hyperplasia , +60% +/- 33 for the hemangiomas; metastases and cyst enhancement wer e not significant. After SPIO on TFE T1-weighted images, the hemangiom a-to-liver signal ratio (149% +/- 18) was definitely higher than the m ean metastasis-to-liver signal ratio (90% +/- 16). This T1-related dif ferentiation ability lacked dramatically on TFE MXT images and, in one case, was reduced on post-SPIO TFE T1-weighted images by a long imagi ng delay after SPIO administration (2 hours).