MedWire News: The latest generation of dual-energy X-ray absorptiometry (DXA) imaging is on a par with conventional radiography for the diagnosis of vertebral fractures, Italian researchers report.
Indeed, they say that DXA offers a number of advantages over radiography, while some limitations remain to be overcome.
Guiseppe Guglielmi (University of Foggia) and team compared the diagnostic performance of DXA with standard radiography in 68 consecutive patients (814 verterbrae) admitted with suspected vertebral fractures.
Thirty-eight of the patients were men, the mean age was 58.1 years, mean body index was 25.1 kg/m2, and indications included clinically suspected or diagnosed osteoporosis, chronic corticosteroid treatments, and follow-up after organ transplantations.
Reporting their findings in Bone, Guglielmi et al reveal that there were 40 "true" fractures in 26 patients, giving an incidence of 4.9%.
In all, 25 fractures were considered mild, 12 moderate, and three severe; 26 were wedge-type and 14 were biconcave, with no instances of crush fracture.
Using radiography as the gold standard, lesion-based analysis showed that DXA had a sensitivity, specificity, accuracy (area under the curve), positive predictive value, and negative predictive value of 70.0%, 98.3%, 0.842, 68.3%, and 98.4%, respectively.
In a patient-based analysis, DXA had a sensitivity, specificity, and accuracy of 73.1%, 90.5%, and 0.818, respectively.
Importantly, the experience of the radiologists did not significantly influence the accuracy, sensitivity, or specificity of DXA. However, both sensitivity and specificity were slightly higher for moderate-severe fractures than for mild fractures.
Finally, intra-observer agreement was excellent whereas inter-observer agreement was fair to good.
Guglielmi et al conclude: "Our study confirms that latest improvements in DXA technology allow a very reliable assessment of vertebral fractures and make DXA more competitive with traditional radiographic gold standard.
"Although consistent advantages and attractions are provided by new DXA, few limitations still affect diagnostic performance and need to be overcome."
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