MRI of the spine: image quality and normal-neoplastic bone marrow contrast at 3 T versus 1.5 T.

Abstract

The objectives of our study were to compare image quality of the spine and visualization of spine abnormalities at 3 T and 1.5 T as well as to evaluate differences in quantitative assessment of normal and neoplastic vertebral bone marrow. One hundred nine MR examinations of the spine were performed at 1.5 T and 3 T in the same patients within a time interval of less than 3 months. Visualization of anatomic and pathologic structures was analyzed by two radiologists. Normal and pathologic bone marrow was assessed on T1-weighted fast spin-echo (FSE) sequences. The signal intensity contrast of neoplastic bone marrow versus normal vertebral bone marrow was measured at 1.5 T versus 3 T. Sensitivity, specificity, and accuracy with 95% CIs were computed to assess the performance of muscle and disk as standards to differentiate between neoplastic and normal bone marrow on T1-weighted sequences at 1.5 T and 3 T. For all anatomic structures evaluated, image quality was rated significantly higher at 3 T than at 1.5 T, with 71.6% of the studies overall being superior at 3 T. The contrast between normal and pathologic bone marrow was significantly larger at 3 T (mean +/- SD, 0.33 +/- 0.13) than at 1.5 T (0.27 +/- 0.11). The highest accuracy was found using muscle signal at 3 T to differentiate between normal and pathologic bone marrow. The use of 3-T MRI improves visualization of anatomic structures in the spine over 1.5-T MRI. As an internal standard on T1-weighted FSE images, skeletal muscle can be used to differentiate between infiltrative and normal bone marrow with higher accuracy at 3 T than at 1.5 T.