MR-based proton density fat fraction (PDFF) of the vertebral bone marrow differentiates between patients with and without osteoporotic vertebral fractures

• Published in: Osteoporosis international Vol. 33; no. 2; pp. 487 - 496
• Main Authors: Gassert, F. T., Kufner, A., Gassert, F. G., Leonhardt, Y., Kronthaler, S., Schwaiger, B. J., Boehm, C., Makowski, M. R., Kirschke, J. S., Baum, T., Karampinos, D. C., Gersing, A. S.
• Format: Journal Article
• Language: English
• Published: London Springer London 01-02-2022; Springer Nature B.V
• Subjects: Biomarkers; Bone Density; Bone imaging; Bone marrow; Bone Marrow - diagnostic imaging; Bone mineral density; Cancellous bone; Computed tomography; Endocrinology; Energy; Female; Fractures; Humans; Lumbar Vertebrae - diagnostic imaging; Magnetic Resonance Imaging; Male; Medicine; Medicine & Public Health; Original; Original Article; Orthopedics; Osteoporosis; Osteoporotic Fractures - diagnostic imaging; Osteoporotic Fractures - etiology; Protons; Regression analysis; Rheumatology; Spinal Fractures - diagnostic imaging; Spinal Fractures - etiology; Spine (lumbar); Vertebrae; magnetic resonance imaging; spine; osteoporosis; bone marrow
• ISSN: 0937-941X; 1433-2965
• DOI: 10.1007/s00198-021-06147-3

Summary
The bone marrow proton density fat fraction (PDFF) assessed with MRI enables the differentiation between osteoporotic/osteopenic patients with and without vertebral fractures. Therefore, PDFF may be a potentially useful biomarker for bone fragility assessment.
Introduction
To evaluate whether magnetic resonance imaging (MRI)-based proton density fat fraction (PDFF) of vertebral bone marrow can differentiate between osteoporotic/osteopenic patients with and without vertebral fractures.
Methods
Of the 52 study patients, 32 presented with vertebral fractures of the lumbar spine (66.4 ± 14.4 years, 62.5% women; acute low-energy osteoporotic/osteopenic vertebral fractures,
N
 = 25; acute high-energy traumatic vertebral fractures,
N
 = 7). These patients were frequency matched for age and sex to patients without vertebral fractures (
N
 = 20, 69.3 ± 10.1 years, 70.0% women). Trabecular bone mineral density (BMD) values were derived from quantitative computed tomography. Chemical shift encoding-based water-fat MRI of the lumbar spine was performed, and PDFF maps were calculated. Associations between fracture status and PDFF were assessed using multivariable linear regression models.
Results
Over all patients, mean PDFF and trabecular BMD correlated significantly (
r
 =  − 0.51,
P
 < 0.001). In the osteoporotic/osteopenic group, those patients with osteoporotic/osteopenic fractures had a significantly higher PDFF than those without osteoporotic fractures after adjusting for age, sex, weight, height, and trabecular BMD (adjusted mean difference [95% confidence interval], 20.8% [10.4%, 30.7%];
P
 < 0.001), although trabecular BMD values showed no significant difference between the subgroups (
P
 = 0.63). For the differentiation of patients with and without vertebral fractures in the osteoporotic/osteopenic subgroup using mean PDFF, an area under the receiver operating characteristic (ROC) curve (AUC) of 0.88 (
P
 = 0.006) was assessed. When evaluating all patients with vertebral fractures, those with high-energy traumatic fractures had a significantly lower PDFF than those with low-energy osteoporotic/osteopenic vertebral fractures (
P
 < 0.001).
Conclusion
MR-based PDFF enables the differentiation between osteoporotic/osteopenic patients with and without vertebral fractures, suggesting the use of PDFF as a potential biomarker for bone fragility.