Assessment of risk of osteoporosis : use of ultrasound measurements
Ultrasound has been suggested as a possible tool for assessing those at risk of osteoporosis. It not only measures density, but also a structural element of the bone, which has yet to be quantified fully. Precision was examined, and was found to have a similar precision to that of the hip scan dual energy x-ray absorptiometry (DXA), with DXA of the spine having a superior precision. Ultrasound as a screening tool at the menopause was also examined, showing that the two methods are identifying different people to be at risk. However a significant correlation of around 0.3 was found between the two machines with around 12.5% of the variation in ultrasound being accounted for by density. Ultrasound was examined in patients with hip, Colles' an vertebral fractures versus controls. This showed ultrasound to be as good as DXA for discriminating hip and Colles fracture. However for vertebral fractures in females DXA of the spine is superior. For men neither DXA nor ultrasound can discriminate well. Perimenopausal women were followed up to prospective fractures. It was found that none of the measurements had a superior predictive ability, although it was found that DXA spine seemed to be best, with a combination of ultrasound and DXA hip also proving to have a good predictive ability. Elderly patients with hip fractures were also examined in a prospective study to determine which technique to predict those patients who suffered a second hip fracture in a 2 year follow-up period. Again no significant differences were found in the predictive ability of ultrasound and DXA. Overall ultrasound seems as good a discriminator/predictor of those at risk of osteoporosis. Further work is required to improve precision in the ultrasound equipment. More study is also needed to determine and quantify exactly the parameters that ultrasound measures.