Abdominal CT comparable to DXA for osteoporosis screening
A new study published this week found that abdominal CT scans could be a feasible option for bone density screenings, as the modality achieved results comparable to those yielded by traditional DXA scans.
For the study, researchers measured bone mineral density (BMD) using axial CT attenuation at L1 and compared those results with L1 DXA T-scores. For the 407 participants, L1 density derived from CT scans was found to have significant correlation with L1 DXA T-scores.
Current practice involves screening age-eligible patients for fracture risk using DXA scans that measure BMD of different body regions—most commonly the femoral neck and lumbar spine. But the experts pointed out that by the time patients reach the age when they become eligible for screening, many of them might already have developed irreversible bone fragility.
However, a screening opportunity is presented when individuals undergo abdominal CT scans for other various indications.
“This method involves BMD estimation in Hounsfield units (HU) at bony landmarks,” corresponding author H. Abbouchie, of the Department of Radiology at Austin Health in Australia, and co-authors write. “The first lumbar vertebra (L1) has been studied widely, with evidence that L1 density measured on CT correlates with lowest reported central DXA readings.”
For the study, researchers retrospectively compared BMD measurements on patients who underwent both an abdominal CT scan and a DXA scan within a 12-month period. Sensitivity, specificity, area under the curve (AUC), and odds ratio (OR) were calculated for a total of 407 patients, 11.8% of whom were diagnosed with osteoporosis.
Outside of the correlation between measurements of both men and women obtained from both modalities, the researchers also identified HU thresholds that could reliably rule out osteoporosis. For women, a threshold of 190 HU decreased the probability of osteoporosis, garnering a negative predictive value (NPV) of 94.4% in the study. For all participants, a threshold of 180 HU was found to have a 96.2% NPV and served as a reliably rule out osteoporosis.
“As yet, this technique has not been clinically implemented locally, manually nor automated with software. In a practical clinical setting, L1 attenuation measurements can be calculated automatically and documented with abdominal CT reports using artificial intelligence algorithms without additional time or effort from reporting radiologists,” the authors wrote before noting that this technique is cost-friendly and convenient for patients.
The full study can be viewed in Clinical Radiology.
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.