CLINICAL-EVALUATION OF SPINE MORPHOMETRIC X-RAY ABSORPTIOMETRY

A new method for vertebral height measurements, morphometric X-ray abs orptiometry (MXA) based on dual-energy X-ray absorptiometry, has been proposed. This technique overcomes some limitations of morphometric ra diography (MRX): the effective radiation dose is low, some sources of geometric distortion are eliminated, such as dependence on patient pos ition, magnification gradient, and the effect of scoliosis is minimize d. The purpose of this study was to compare morphometric parameters ob tained by both methods (MXA and MRX), and to evaluate the agreement be tween morphometric evaluations and qualitative reading for vertebral f racture diagnosis. The evaluation was performed with an Hologic QDR 20 00 device in 67 women without vertebral fractures and 31 women with ve rtebral fractures (according to a qualitative assessment). The reprodu cibility of the image analysis was <4% and comparable to MRX. The esti mated bias between the two methods was on average 10 mm, and was a fun ction of the vertebral height, according to the Bland and Altman metho d. The agreement between MXA and other methods for vertebral fracture diagnosis was poor for the thoracic level above T7, due to a lack of r esolution and rib interposition. Agreement was also low for T10, due t o the motion of the diaphragm muscle. MXA cannot currently be used for the diagnosis of thoracic vertebral fracture in clinical practice. Te chnological improvements are necessary to make this promising method u seful as a screening tool to evaluate the presence of thoracic vertebr al fractures.