Low Unsaturated Fatty Acids Level in the Vertebral Bone Marrow of Postmenopausal Osteoporosis: A Pilot 2D iDQC-MRS on 3.0 T Study.

BACKGROUND: Unsaturated fatty acids (UFAs) of bone marrow play a critical role in osteoporosis. However, it is difficult to resolve the UFA, especially in the presence of trabecular bone, using conventional magnetic resonance spectroscopy (MRS) methods.

PURPOSE: To preliminarily compare the bone marrow fatty acids (FAs) composition in the presence of trabecular bone of postmenopausal osteoporosis (PMOP) and healthy controls (HC).

STUDY TYPE: Prospective.

SUBJECTS: Total thirty-six postmenopausal women were recruited with CT-confirmed PMOP (n = 19) and HC (n = 17).

FIELD STRENGTH/SEQUENCES: A 3 T scanner. Localized 2D intermolecular double-quantum coherence-based MRS (iDQC-MRS).

ASSESSMENT: In addition to the conventional water and fat peaks, another four crossing peaks of the FAs were well resolved from the L4 vertebral bone marrow using iDQC-MRS technique: allylic methylene (2.0 ppm), terminal methylene (2.2 ppm), diallylic methylene (2.7 ppm), and olefinic (5.3 ppm). The monounsaturated fatty acids (MOFA) and polyunsaturated fatty acids (PUFAs) were then calculated.

STATISTICAL TESTS: Differences between PMOP and HC were investigated using the analysis of a t-test, and the relationships were investigated using regression analysis.

RESULTS: MOFAs and PUFAs fractions were significantly lower in the PMOP group compared to the HC group. In contrast, the saturated FAs fraction is significantly higher in the PMOP group. Additionally, decreased PUFAs, MOFAs were moderately negatively correlated with the volumetric bone mineral density (vBMD) in the PMOP group. Furthermore, increased SFAs in PMOP were strongly associated with vBMD.

DATA CONCLUSION: Using spectra resolution enhanced 2D iDQC-MRS technique, we observed low unsaturated FAs levels in the vertebral bone marrow of the PMOP patients. The reduced unsaturated FAs levels in PMOP may be associated with dysfunction of the balance between osteoblastogenesis and osteoclastogenesis.

LEVEL OF EVIDENCE: 2: 1.