Focal hepatic lesions: comparative MR imaging at 0.5 and 1.5 T.

Twenty-nine patients with known or suspected malignancy were studied with identical T1-weighted (spin echo [SE] and inversion recovery [IR]) and T2-weighted SE magnetic resonance (MR) imaging at 0.5 and 1.5 T to evaluate the relative sensitivities of these sequences for detecting focal hepatic lesions. At 0.5 T, 98 lesions were detected with the IR sequence, 86 with the T1-weighted SE sequence, and 96 with the T2-weighted sequence. At 1.5 T, 93 lesions were detected with the IR sequence, 70 with the T1-weighted SE sequence, and 99 with the T2-weighted sequence. Although the lack of pathologic correlation precluded establishment of true sensitivity and specificity rates, data showed that magnetic field strength resulted in no significant difference for detecting focal hepatic lesions. No single sequence was shown to be significantly superior, although the T1-weighted SE sequence at 1.5 T was significantly inferior to the other sequences for detecting focal hepatic lesions. T1-weighted SE imaging at 0.5 T was significantly inferior to T1-weighted IR and T2-weighted imaging at both magnetic field strengths for detecting focal lesions in the left lobe of the liver. The authors conclude that T1-weighted IR and T2-weighted sequences alone will result in optimal MR imaging for the detection of focal hepatic lesions at 0.5 and 1.5 T.