Improved contrast for myeloma focal lesions with T2-weighted Dixon images compared to T1-weighted images

Abstract

PurposeThe purpose of this study was twofold. First, to compare the contrast between spinal multiple myeloma (MM) focal lesions and surrounding bone marrow obtained on T2-weighted Dixon fat-only MR images to that obtained on T1-weighted spin-echo images. Second, to search for correlation between bone marrow fat fraction assessed by T2-weighted Dixon sequence and International Myeloma Working Group myeloma defining events. Materials and methodsA total of 39 patients with 112 focal MM lesions were included. There were 25 men and 14 women with a mean age of 68.8±9.8 [SD] years (range: 49-88 years). Contrast between focal MM lesions and surrounding bone marrow was calculated on T1-weighted spin-echo and T2-weighted Dixon (including water-only and fat-only) images. Contrast between focal MM lesions and bone marrow was compared using ANOVA and post-hoc Tukey tests. Correlation between bone marrow fat fraction and myeloma defining events was assessed using Spearman's correlation test. ResultsMM lesion contrast was greater on T2-weighted Dixon (F (2;93)=35.10) than on T1-weighted images (P<0.0001). Greatest MM lesion contrast was achieved with T2-weighted Dixon fat-only (0.63±0.21 [SD]; range: 0.06–0.91) compared to T2-weighted Dixon water-only (0.45±0.20 [SD]; range: 0.07–0.8) (P=0.0003) and T1-weighted (0.23±0.19 [SD]; range: 0.04–0.87) (P<0.0001) images. There were no significant correlations between myeloma defining events and fat fraction. ConclusionT2-weighted Dixon fat-only images provide greater contrast between MM lesions and adjacent bone marrow than T1-weighted images. The usefulness of a T1-weighted sequence associated to a T2-weighted Dixon sequence has to be determined.