Objective: Fat-saturation pulse sequences offer important potential advantages for depiction of bone marrow lesions on MR images. The objectives of this study were to evaluate the relative conspicuousness of bone marrow lesions on images obtained by using two of the most widely available fat-suppression techniques, short-TI inversion recovery (STIR) and fat-saturation T2-weighted imaging, and to analyze the effect of these methods on image quality. In addition, we sought to determine if either or both of these sequences provide significant advantages relative 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 [TR/TE/TI]), and fat-saturation T2-weighted (2500/20-70) MR images were obtained with a 1.5-T system in 34 consecutive 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 extent of the lesion, image uniformity, motion artifacts, and overall image quality. In addition, lesion contrast on these sequences was compared quantitatively by using percentage contrast measurements.
Results: Lesions were qualitatively equally conspicuous with all four pulse sequences. Quantitative measurements indicated that lesions were more conspicuous on fat-saturation T2-weighted and STIR images than on T1-weighted 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 T2-weighted, and STIR sequences all provide a high degree of sensitivity for depiction of most types of bone marrow abnormalities. Although the conspicuousness of lesions is similar on fat-saturation T2-weighted and STIR images, the former sequence has several practical advantages, including acquisition of more slices per unit time and improved tissue specificity. The combination of T1-weighted and either fat-saturation T2-weighted or STIR images is highly effective for the evaluation of bone marrow lesions.