MR-IMAGING OF BONE-MARROW LESIONS - RELATIVE CONSPICUOUSNESS ON T1-WEIGHTED, FAT-SUPPRESSED T2-WEIGHTED, AND STIR IMAGES

OBJECTIVE. Fat-saturation pulse sequences offer important potential ad vantages for depiction of bone marrow lesions on MR images. The object ives of this study were to evaluate the relative conspicuousness of bo ne marrow lesions on images obtained by using two of the most widely a vailable fat-suppression techniques, short-TI inversion recovery (STIR ) and fat-saturation TP-weighted imaging, and to analyze the effect of these methods on image quality. In addition, we sought to determine i f either or both of these sequences provide significant advantages rel ative to conventional T1-weighted spin-echo images for the evaluation of bone marrow lesions. SUBJECTS AND METHODS. T1-weighted (600/15 [TR/ TE]), STIR (2500/20/160 [TW TE/TI]), and fat-saturation TS-weighted (2 500/20-70) MR images were obtained with a 1.5-T system in 34 consecuti ve patients with suspected bone marrow lesions. The conspicuousness of 36 lesions was evaluated subjectively by three radiologists, who also evaluated the MR images for how well they showed margination and exte nt of the lesion, image uniformity, motion artifacts, and overall imag e quality. In addition, lesion contrast on these sequences was compare d quantitatively by using percentage contrast measurements. RESULTS. L esions were qualitatively equally conspicuous with all four pulse sequ ences. Quantitative measurements indicated that lesions were more cons picuous on fat-saturation T2-weighted and STIR images than on T1-weigh ted images (p<.001). Differences between the first two sequences were not significant. Factors related to image quality, including reduction in motion artifacts and image uniformity, were generally superior on T1-weighted images. CONCLUSION. T1-weighted, fat-saturation TS-weighte d, and STIR sequences all provide a high degree of sensitivity for dep iction of most types of bone marrow abnormalities. Although the conspi cuousness of lesions is similar on fat-saturaton TS-weighted and STIR images, the former sequence has several practical advantages, includin g acquisition of more slices per unit time and improved tissue specifi city. The combination of TI-weighted and either fat-saturation TS-weig hted or STIR images is highly effective for the evaluation of bone mar row lesions.