7 Tesla MRI of bone microarchitecture discriminates between women without and with fragility fractures who do not differ by bone mineral density

Abstract

Osteoporosis is a disease of poor bone quality. Bone mineral density (BMD) has limited ability to discriminate between subjects without and with poor bone quality, and assessment of bone microarchitecture may have added value in this regard. Our goals were to use 7 T MRI to: (1) quantify and compare distal femur bone microarchitecture in women without and with poor bone quality (defined clinically by presence of fragility fractures); and (2) determine whether microarchitectural parameters could be used to discriminate between these two groups. This study had institutional review board approval, and we obtained written informed consent from all subjects. We used a 28-channel knee coil to image the distal femur of 31 subjects with fragility fractures and 25 controls without fracture on a 7 T MRI scanner using a 3-D fast low angle shot sequence (0.234 mm × 0.234 mm × 1 mm, parallel imaging factor = 2, acquisition time = 7 min 9 s). We applied digital topological analysis to quantify parameters of bone microarchitecture. All subjects also underwent standard clinical BMD assessment in the hip and spine. Compared to controls, fracture cases demonstrated lower bone volume fraction and markers of trabecular number, plate-like structure, and plate-to-rod ratio, and higher markers of trabecular isolation, rod disruption, and network resorption (p < 0.05 for all). There were no differences in hip or spine BMD T-scores between groups (p > 0.05). In receiver-operating-characteristics analyses, microarchitectural parameters could discriminate cases and controls (AUC = 0.66–0.73, p < 0.05). Hip and spine BMD T-scores could not discriminate cases and controls (AUC = 0.58–0.64, p ≥ 0.08). We conclude that 7 T MRI can detect bone microarchitectural deterioration in women with fragility fractures who do not differ by BMD. Microarchitectural parameters might some day be used as an additional tool to detect patients with poor bone quality who cannot be detected by dual-energy X-ray absorptiometry (DXA).

Daily parathyroid hormone administration enhances bone turnover and preserves bone structure after severe immobilization-induced bone loss

“…; Chang et al. ). These effects of PTH on bone formation and bone structure and architecture are consistent with those reported under other hindlimb unloading conditions (Ma et al.…”

Effects of a 12-Month Supervised, Community-Based, Multimodal Exercise Program Followed by a 6-Month Research-to-Practice Transition on Bone Mineral Density, Trabecular Microarchitecture, and Physical Function in Older Adults: A Randomized Controlled Trial

“…In addition, this assessment was limited to the proximal femur and distal tibia, which are not common fracture sites. However, there is some evidence the MRI‐derived bone microarchitectural parameters at these sites differs between women with fragility fractures and controls . Fourth, detailed information was not recorded on the number of training sessions supervised by the exercise trainers nor the exercise progressions during the final 6‐month transition.…”

Tissue-Level Mechanical Properties of Bone Contributing to Fracture Risk

“…Nonetheless, the clinical importance of tissue to fracture resistance is apparent from the literature on predictors of fracture risk as well as genetic diseases affecting bone matrix (e.g., osteogenesis imperfecta) or mineralization (e.g., hypophosphatasia). As determined by high-resolution, peripheral quantitative computed-tomography (HR-pQCT) or micro-magnetic resonance imaging (μMRI), measurements of cortical thickness, cross-sectional area, volumetric bone mineral density (vBMD), porosity, and trabecular bone volume fraction acquired at distal sites significantly differ between individuals with osteoporotic fractures and those without fractures [3–5]. However, there is overlap in all structural and architectural measurements of bone between these two groups such that there is no one bone property – including the gold-standard areal bone mineral density (aBMD) [6] – that unequivocally predicts fracture risk.…”