Vertebrae adjacent to spinal bone lesion are inconsistent reference markers: A magnetic resonance spectroscopic viewpoint

Purpose: To ascertain the suitability of vertebrae adjacent to spinal bone lesions as a signal intensity reference on MRI. and compare the MR spectroscopic appearance of vertebral body compression fractures due to malignant tumor infiltration, bone weakening (e.g., osteoporosis), and/or minor trauma. Materials and Methods: Twenty-five patients with spinal compression fractures underwent routine spinal MRI with an additional H-1 MRS study protocol to assess the percent fat fraction of the compressed vertebrae as well as the adjacent bony environment. Peak areas for water and total lipid were calculated from short-TE single-voxel H-1 MR spectra using the LCModcl analyzing tool. Results: There were consistent water-only patterns in the fractured vertebra suggesting either near complete marrow replacement by malignant tissue or local edematous fluid/ hemorrhage within the marrow spaces. However, the adjacent vertebrae showed a wide range of patterns from a dominant lipid signal to the inverse of a pronounced water level. These results far exceed the normal variation expected based on age and sex. Conclusion: The results suggest that the adjacent vertebrae may not be an accurate reference, especially in diffusion-weighted imaging (DWI), because of the large difference between the two compartments. Furthermore, in the case of gradient-echo measurements, the in-phase vs. opposed-phase effects are significant.