MRI-based abnormalities in young adults at risk of adverse bone health due to childhood-onset metabolic & endocrine conditions.

Objective Traditional methods of bone densitometry may not provide a comprehensive assessment of bone health. We aimed to assess bone micro-architecture and bone marrow adiposity ( BMA) by MRI in adults with osteogenesis imperfecta ( OI) and endocrinopathy including GH deficiency and/or hypogonadism. Measurements High-resolution micro- MRI images were acquired at the tibia using 3T MRI to calculate parameters of bone micro-architecture in seven adults with OI and 10 adults with endocrinopathies. MR Spectroscopy was performed in participants to calculate vertebral BMA, which was expressed as percentage fat fraction (% FF). Lumbar spine DXA was performed to assess bone mineral density. The MRI data were compared with a group of 22 healthy adults who were divided into two age-matched control groups. Results Intra-operator repeatability was high, with an average CoV of 1% for micro- MRI and 2·5% for MRS. The ratio of apparent bone volume to total volume (app BV/ TV) in the endocrinopathy and OI groups was lower than in age-matched control groups ( P = 0·003 and P = 0·008 respectively). A weak association between DXA BMD and app BV/ TV was also observed ( r = 0·5, P = 0·045). % FF was higher in the endocrinopathy group than in the age-matched control group ( P = 0·005), but no difference in % FF was observed between the OI group and their age-matched control group ( P = 0·26). Conclusions MRI provides valuable detailed information on the micro-architecture and adiposity of bones and is capable of showing clear differences in bone parameters in a range of clinical conditions associated with abnormal bone health. [ABSTRACT FROM AUTHOR]