Exploring bone density analysis on routine CT scans as a tool for opportunistic osteoporosis screening

Area of Science:

• Radiology
• Intensive Care Medicine
• Bone Metabolism

Background:

• Decreased bone density is a concern for intensive care unit (ICU) patients.
• Screening for osteoporosis in critically ill patients is challenging.
• Computed tomography (CT) scans are routinely performed in ICUs.

Purpose of the Study:

• To evaluate CT-based bone density analysis of the 12th thoracic vertebra (Th12) as a screening tool for reduced bone density in ICU patients.
• To determine the prevalence of low bone density in COVID-19 patients admitted to the ICU.
• To assess the impact of prolonged ICU stays on bone density.

Main Methods:

• Retrospective analysis of 118 CT scans from 38 COVID-19 patients admitted to the ICU.
• Bone density was measured at the Th12 level using Hounsfield Units (HU).
• Interobserver variability and the effect of contrast administration were assessed.

Main Results:

• Good interobserver agreement was observed (Intraclass Correlation Coefficient [ICC] = 0.93).
• Contrast enhancement slightly increased bone density measurements (+7.5 HU).
• 37% of patients exhibited bone density <140 HU, indicative of osteoporosis.
• No significant difference in bone density was found between admission and follow-up scans (≥21 days).

Conclusions:

• Vertebral CT-based bone density analysis is a feasible method for screening ICU patients for decreased bone density.
• A high prevalence of low bone density was identified in the studied COVID-19 ICU cohort.
• Long-term ICU stay did not significantly alter bone density in this patient group.