Opportunistic Screening for Low Bone Mineral Density in Routine Computed Tomography Scans: A Brazilian Validation...

Area of Science:

• Radiology
• Osteoporosis Research
• Public Health

Background:

• Osteoporotic fractures pose a significant global health burden, leading to mortality, reduced quality of life, and high healthcare expenses.
• A critical gap exists in osteoporosis screening, with most fracture patients never formally assessed for the condition.
• Opportunistic screening via conventional computed tomography (CT) offers a potential solution to identify individuals with low bone mass.

Purpose of the Study:

• To validate the use of conventional CT scans for opportunistic screening of osteopenia and osteoporosis in Brazilian patients.
• To assess the correlation between CT attenuation values and bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA).

Main Methods:

• Retrospective analysis of 491 patients who underwent both unenhanced CT and DXA scans within six months.
• Measurement of mean CT attenuation in the first lumbar vertebra (L1) across different planes.
• Establishment of potential thresholds for low BMD using receiver operating characteristic (ROC) analysis.

Main Results:

• Significantly lower mean L1 CT attenuation was observed in osteopenic and osteoporotic patients (p < 0.001).
• Strong positive linear correlations were found between DXA T-scores and L1 CT attenuation values (p < 0.001).
• An average L1 sagittal plane attenuation ≤ 100 Hounsfield Units (HU) identified low BMD with 96.3% specificity and 96% positive predictive value. An L1 sagittal plane attenuation > 180 HU showed 97.6% sensitivity and 94.9% negative predictive value for osteoporosis. Patients with L1 sagittal attenuation ≤ 100 HU had a significantly higher prevalence of vertebral fractures (prevalence ratio: 8.67; p < 0.001).

Conclusions:

• Routine CT scans can serve as a cost-effective, radiation-free tool for opportunistic screening of probable low bone density in Brazilian patients.
• Opportunistic CT screening complements, but does not replace, formal bone mineral density assessment.
• This approach helps identify patients who could benefit from further evaluation and management of osteoporosis.