Background/Purpose: A major obstacle to the treatment of osteoporosis and prevention of fractures is that many at-risk patients are never screened. Dual energy x-ray absorptiometry (DXA) measurements of bone mineral density, the gold standard for diagnosis of osteoporosis, are only performed in a minority of patients. Therefore, opportunistic methods using imaging obtained for other clinical purposes are needed to foster identification and treatment. The aim of this pilot study was to investigate textural analysis of MRI scans of the lumbar spine (LS) as a measure of bone quality. We hypothesized: 1) similar to trabecular bone score (TBS) derived from DXA, textural analysis of MRI would provide an assessment of bone quality based upon trabecular (Tb) bone distribution and 2) Tb bone heterogeneity measured by MRI texture analysis would be higher in those with a history of fragility fracture compared to healthy controls.

Methods: In this study, we analyzed LS MRI scans of 30 patients. Cases (n=15) were postmenopausal women with a radiographically confirmed fragility fracture. Controls (n=15) were healthy women aged 25-35 years. Tb bone from the lumbar vertebrae was segmented to create regions of interest (ROIs). Fractured or previously instrumented vertebrae were excluded. A gray level co-occurrence matrix (GLCM) was then created to quantify the distribution and spatial organization of pixels within the Tb bone ROI. Heterogeneity in Tb bone texture was assessed by the following independent parameters, both globally as well as in anatomic directions: contrast (variability), entropy (disorder) and angular second moment (homogeneity) [figure]. Texture measures were compared using the Wilcoxon rank-sum test.

Results: Measures of Tb bone heterogeneity were worse in fracture patients, who had 139% higher contrast, 14% higher entropy and 60% lower angular second moment compared to controls (all p< 0.05). Contrast was the measure that most effectively discriminated between groups: fracture patients had 128-161% higher values in the vertical, horizontal, diagonal and through planes (all p< 0.05).

Conclusion: In summary, textural analysis of Tb bone discriminated between patients with known osteoporotic fractures and controls. Our results demonstrate the feasibility of applying this technique to MRI to evaluate Tb bone quality. Further investigation is required to validate this promising methodology, which has the potential to greatly expand the number of patients screened for skeletal fragility. 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/mri-based-textural-analysis-of-trabecular-bone-a-novel-method-for-the-opportunistic-screening-of-bone-quality/