Summary: A study shows photon-counting detector CT can effectively derive T-scores, serving as a potential tool for opportunistic bone density screening with high concordance to dual-energy X-ray absorptiometry results.
Key Takeaways
- Photon-counting detector CT can effectively derive area bone mineral density values and T-scores, showing potential as a screening tool for low bone mass and osteoporosis.
- The study demonstrated a high concordance (0.90) between T-scores derived from photon-counting CT and dual-energy X-ray absorptiometry (DXA) results.
- Photon-counting CT accurately classified 90.2% of patients as having normal or abnormal bone mass compared to DXA standards.
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An accepted manuscript in the American Journal of Roentgenology (AJR) reports that photon-counting detector (PCD) CT spectral localizers have clinical utility for deriving area bone mineral density (aBMD) values and T-scores.
Addressing low adherence to dual-energy X-ray absorptiometry (DXA) screening guidelines, “the T-score derived from PCD-CT spectral localizers may serve as an opportunistic screening tool for low bone mass and osteoporosis,” says senior author Francis I. Baffour, MD, 2024 AJR Melvin M. Figley Fellow, from Mayo Clinic’s radiology department in Rochester, Minn.
This prospective AJR study included patients aged 18 and older who had clinically indicated lumbar spine CTs between October 2023 and February 2024, as well as DXA scans within 13 months before or after the CT. Patients underwent lumbar spine CT with PCD, generating spectral localizer images.
Bone Mass Classification vs. DXA
Baffour’s team used regions of interest (ROIs) on lumbar vertebrae and background soft tissues for material decomposition, deriving areal densities and lumbar spine aBMD values, which were converted into T-scores classified as normal (≥-1) or abnormal (<-1) bone mass. These were compared with DXA-derived values.
The results showed a mean DXA T-score of 0.39±1.64 and a mean PCD-CT T-score of 0.28±1.77 (p=.29). The concordance correlation coefficient between DXA and PCD-CT T-scores was 0.90. PCD-CT accurately classified 90.2% of patients (46/51) as normal or abnormal in bone mass compared to DXA.
Featured image: 68-year-old woman who underwent clinically indicated CT of lumbar spine due to persistent low back pain, despite more than 6 weeks of conservative therapy.
