Bone texture by clinical magnetic resonance imaging is directly related to bone tissue maturity by Fourier-transform infrared spectroscopy.

Abstract

Opportunistic screening for osteoporosis using images acquired for other purposes is a burgeoning area that may be of particular utility for the identification of surgical candidates with poor bone health. Texture analysis of clinical MRIs can be used to evaluate the heterogeneity of trabecular bone as a potential metric of bone quality. This cohort study investigated relationships between MRI-based vertebral trabecular bone texture and material properties by Fourier-transform infrared (FTIR) spectroscopy. We hypothesized that texture features from preoperative MRI images would reflect vertebral bone mineralization and collagen properties. In a cohort of 30 postmenopausal women (mean age 65) undergoing spine fusion surgery, T1-weighted MRI images were obtained using standard clinical sequences. A gray-level co-occurrence matrix was used to characterize the distribution and spatial organization of voxel intensities and derive texture features, including inverse difference moment, feature correlation, and contrast. Lumbar vertebral bone biopsies were obtained intraoperatively and analyzed with FTIR spectroscopy to assess composition, including metrics of mineral maturity (acid phosphate and carbonate:phosphate ratio). We found that vertebral trabecular bone texture by MRI was related to directly measured bone material properties: more heterogeneous texture was associated with less mature bone. Women with lower inverse difference moment had higher acid phosphate (r = -0.43, p < .02). Similarly, women with lower feature correlation had higher acid phosphate (r = -0.39, p < .04) and higher carbonate: phosphate (r = -0.47, p < .01). Women with higher contrast had higher acid phosphate (r = 0.381, p < .04). Our results suggest that preoperative MRI texture may predict intraoperative bone properties, specifically FTIR metrics of tissue age that may reflect local remodeling or microdamage repair processes. This finding supports the potential of MRI as a screening tool to identify individuals with abnormal bone quality.