Dilara ATASOY, Ayşegül CANSU, Murat KARKUCAK, İlker EYÜBOĞLU

Diagnostic efficacy of routine contrast-enhanced abdominal CT for the assessment of osteoporosis in the Turkish population

Background/aim: This study aimed to evaluate the diagnostic efficacy of vertebral Hounsfield unit (HU) values on routine contrastenhancedabdominal computed tomography (CT) scans for the assessment of osteoporosis using dual-energy X-ray absorptiometry(DXA) T-scores as a reference standard.Materials and methods: A total of 111 consecutive patients who underwent contrast-enhanced abdominal CT examination for anyindication and DXA within a 6-month period were retrospectively analyzed. The CT attenuation values of trabecular bone in HUs weremeasured in axial and sagittal planes from lumbar vertebrae 1–4 (L1–L4). The correlation between the DXA T-scores and HU valuesmeasured on the CT scans was evaluated by Pearson’s correlation test. Areas under the curves (AUCs) were calculated by receiveroperating characteristic analysis for diagnostic proficiency, and threshold values were determined. Paired t-test and Bland–Altman plottest were used to evaluate the correlation between axial and sagittal HU values.Results: There was a strong correlation between the DXA T-scores and HU values of all the lumbar vertebrae (P < 0.001). The highestcorrelation was for the L3 vertebra; L3 was thus chosen for additional analyses. The mean axial and sagittal L3 attenuations were 133.7HU and 131.9 HU, respectively. The axial measurements were not significantly different from the sagittal measurements, with a meandifference of 1.8 HU (P > 0.05). The L3 axial CT attenuation threshold for 90% sensitivity was 170 HU and that for 90% specificity was102 HU for distinguishing osteoporosis from osteopenia and normal bone mineral density (BMD). To distinguish the low BMD groupfrom the normal group, the L3 axial CT attenuation threshold for approximately 90% sensitivity was 102 HU and for 90% specificitywas 165 HU.Conclusion: The HUs derived from routine contrast-enhanced abdominal CT scans can be used for the evaluation of osteoporosis,without additional radiation exposure and cost.

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