Bone marrow fat quantification of osteoporotic vertebral compression fractures: comparison of multi-voxel proton MR spectroscopy and chemical-shift gradient-echo MR imaging

Abstract

Background Only a few studies have used in/opposed phase method for a quantitative evaluation of fat fraction in the spine. Purpose To compare multivoxel proton MR spectroscopy and chemical-shift gradient-echo MR imaging for bone marrow fat quantification in vertebral compression fractures (VCF). Material and Methods Vertebral marrow fat quantification in fifteen patients was measured at 3.0-T. Multi-voxel proton spectroscopy (MRS) and in/opposed-phase MR imaging using a fat map build with a triple-echo gradient-echo sequence was used. All the patients had benign vertebral collapse. Bone marrow fat content was evaluated by both techniques in compressed (acute or chronic) and in non-compressed vertebrae. Results The percentage of fat fraction measured by the triple-echo sequence was well correlated with those calculated by MRS ( r2 = 0.85; P < 10−4). There was a significant decrease of fat fraction in acute VCF versus both chronic VCF ( P < 10−9) and non-fractured vertebrae ( P < 10−7). There was no significant difference in fat fraction evaluated by both techniques between non-fractured vertebrae and chronic VCF. Conclusion We have validated the in/opposed phase method compared with MRS for vertebral bone marrow fat quantification. The fat mapping using a triple-echo gradient-echo sequence allows distinguishing acute and chronic benign VCF.