ACCURACY OF VERTEBRAL FRACTURE ASSESSMENT BY DUAL-ENERGY X-RAY ABSORPTIOMETRY USING GE IDXA COMPARED TO CONVENTIONAL RADIOGRAPHY

26 subjects (9.5%) had multiple vertebral fractures detected by SQ Rx technique and 28 subjects (10.2%) by iDXA . Considering radiological SQ assessment as the gold standard, iDXA sensitivity was 87% and the specificity was 96% (Positive Predictive Value 88%; Objective: This prospective investigation was carried out in order to evaluate the accuracy of vertebral fracture assessment by dual-energy X-ray absorptiometry using GE iDXA device (GE Medical Systems Lunar, Madison, WI, USA) compared to conventional radiography.Subjects and Methods: We enrolled 273 subjects (207 females and 68 males, age range 28-85 years) consecutively studied at our Mineral Metabolism Centre, which were undergoing a spine vertebral X-ray evaluation. Lateral images of the spine, from T4 to L4, by both conventional X-ray and iDXA device, were acquired in each subject on the same day, after informed consent was obtained. The radiographs were evaluated by an experienced skeletal radiologist (D.D.), using the semiquantitative (SQ) method. The iDXA images were evaluated by a trained operator using a specific software (enCORE).Results: By means of SQ radiological technique, we evaluated 3515 (99%) of the 3549 available vertebrae, and identified 151 vertebral deformities (101 mild and 50 moderate or severe). By means of iDXA we visualized 3405 (96%) vertebrae and identified 150 vertebral deformities (100 mild and 50 moderate or severe). Ninety-two subjects (33.7% of the total sample) were identified as having vertebral fractures by SQ Rx technique and eighty-seven subjects (31.9%) fractured were recognized by iDXA (χ2 = n.s.). A single fracture was detected in 66 patients (24.2%) by conventional radiographs and in 59 subjects (21.6%) by iDXA; Negative Predictive Value 97%). Agreement between radiographs and iDXA was 96% with a kappa statistic of 0.91 (confidence interval 0.82-0.96).Conclusions: According to the results obtained, iDXA and SQ radiological technique demonstrated good agreement in classifying vertebrae as normal or deformed. Therefore, since iDXA performs spine images with good resolution and lower dose, it proves to be useful in the clinical evaluation of patients at risk of osteoporosis or for the selection of patients for osteoporosis-related clinical trials.