Quantitative 31P magnetic resonance imaging on pathologic rat bones by ZTE at 7T.

BACKGROUND: Osteoporosis is characterized by low bone mineral density (BMD), which predisposes individuals to frequent fragility fractures. Quantitative BMD measurements can potentially help distinguish bone pathologies and allow clinicians to provide disease-relieving therapies. Our group has developed non-invasive and non-ionizing magnetic resonance imaging (MRI) techniques to measure bone mineral density quantitatively. Dual-energy X-ray Absorptiometry (DXA) is a clinically approved non-invasive modality to diagnose osteoporosis but has associated disadvantages and limitations. PURPOSE: Evaluate the clinical feasibility of phosphorus (31P) MRI as a non-invasive and non-ionizing medical diagnostic tool to compute bone mineral density to help differentiate between different metabolic bone diseases. MATERIALS AND METHODS: Fifteen ex-vivo rat bones in three groups [control, ovariectomized (osteoporosis), and vitamin-D deficient (osteomalacia - hypo-mineralized) were scanned to compute BMD. A double-tuned (1H/31P) transmit-receive single RF coil was custom-designed and in-house-built with a better filling factor and strong radiofrequency (B1) field to acquire solid-state 31P MR images from rat femurs with an optimum signal-to-noise ratio (SNR). Micro-computed tomography (µCT) and gold-standard gravimetric analyses were performed to compare and validate MRI-derived bone mineral densities. RESULTS: Three-dimensional 31P MR images of rat bones were obtained with a zero-echo-time (ZTE) sequence with 468 µm spatial resolution and 12-17 SNR on a Bruker 7 T Biospec having multinuclear capability. BMD was measured quantitatively on cortical and trabecular bones with a known standard reference. A strong positive correlation (R = 0.99) and a slope close to 1 in phantom measurements indicate that the densities measured by 31P ZTE MRI are close to the physical densities in computing quantitative BMD. The 31P NMR properties (resonance linewidth of 4 kHz and T1 of 67 s) of ex-vivo rat bones were measured, and 31P ZTE imaging parameters were optimized. The BMD results obtained from MRI are in good agreement with µCT and gravimetry results. CONCLUSION: Quantitative measurements of BMD on ex-vivo rat femurs were successfully conducted on a 7 T preclinical scanner. This study suggests that quantitative measurements of BMD are feasible on humans in clinical MRI with suitable hardware, RF coils, and pulse sequences with optimized parameters within an acceptable scan time since human femurs are approximately ten times larger than rat femurs. As MRI provides quantitative in-vivo data, various systemic musculoskeletal conditions can be diagnosed potentially in humans.

Multivitamins and risk of fragility hip fracture: a systematic review and meta-analysis.

PURPOSE: Hip fracture is a severe complication of osteoporosis and is associated with a significant healthcare burden worldwide. This meta-analysis explores the association between combined multivitamin use and hip fracture risk. Our results provide more patient-centered insight into the impact of supplement use on osteoporosis outcomes. METHODS: We searched three online databases in August 2019 and included studies that reported on multivitamin use in patients with osteoporotic hip fractures. The inclusion criteria were (1) adult patients with osteoporotic hip fractures, (2) availability of full-text articles in English, and (3) at least 1 year of follow-up. No suitable randomized controlled trials could be identified for inclusion in the analysis. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). RESULTS: Eight studies containing 80,148 subjects in total were included in this study. Among these, 4237 cases of fragility hip fracture were reported. The average age was 69±5.3 years, and 21% of subjects were male. Multivitamin use was found to be significantly associated with a lower risk of sustaining a fragility hip fracture (OR 0.49, 95%CI: 0.32-0.77). The Begg and Mazumdar test and funnel plot indicated that no significant publication bias was present. CONCLUSION: Combined multivitamins are amongst the most widely used supplements and are often preferred over single vitamins. Our meta-analysis indicates that multivitamin use is significantly protective against osteoporotic hip fracture. In the future, randomized controlled trials should be performed to establish multivitamins as effective preventative measures for this injury.