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

Scientific Reports, vol. 14, pp. 18359

Abstract

The primary aim of this study was to evaluate computed tomography (CT)-based bone density analysis at the level of thoracic vertebra 12 (Th12) as a screening method for decreased bone density in patients admitted to the intensive care unit (ICU). Interobserver variability was analyzed. Secondary aims were to assess the prevalence of CT-based low bone density upon ICU admission in a cohort of COVID-19 patients and to assess the potential effect of long-term ICU stay on bone density in these patients. Retrospective single-center cohort study. ICU of the Leiden University Medical Center (LUMC), the Netherlands. Patients admitted to the ICU of the LUMC between March 1st, 2020 and February 1st, 2022 with a diagnosis of COVID-19, and a length of ICU stay of ≥ 21 days. In the included patients both baseline chest CT scans (obtained upon ICU admission) and follow-up chest CT scans (obtained ≥ 21 days after ICU admission) were available for analysis. A total of 118 CT scans in 38 patients were analyzed. There was a good interobserver variability, with an overall mean absolute difference (between measurements of three observers) of 9.7 Hounsfield Units (HU) and an intraclass correlation coefficient (ICC) of 0.93 (95% CI 0.88-0.96). The effect of intravenous contrast administration on bone density measurements was small (+ 7.5 HU (95% CI 3.4-11.5 HU)) higher in contrast enhanced CT images compared to non contrast enhanced CT images). Thirty-seven percent of patients had a bone density < 140 HU, suggestive of osteoporosis. No significant difference was found between bone density upon ICU admission and bone density at follow-up (≥ 21 days after ICU admission). Vertebral CT-based bone density analysis using routine CT scans is an easily applicable method to identify ICU patients with decreased bone density, which could enable enrollment in osteoporosis prevention programs. A high prevalence of low bone density was found in our cohort of ICU patients. There were no changes observed in bone density between baseline and follow-up measurements.

Authors 6

1. Nadia A. du Fossé Aachen Department of Intensive Care

   Leiden University Medical Center

   Affiliation as printed

   Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands

2. Willem Grootjans Aachen Department of Radiology, Leiden University Medical Center

   Leiden University Medical Center

   Affiliation as printed

   Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands

3. Natasha M. Appelman‐Dijkstra Aachen Department of Internal Medicine Center for Bone Quality

   Leiden University Medical Center

   Affiliation as printed

   Department of Internal Medicine, Center for Bone Quality, Leiden University Medical Center, Leiden, The Netherlands

4. Carlos V. Elzo Kraemer Aachen Department of Intensive Care

   Leiden University Medical Center

   Affiliation as printed

   Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands

5. David J. van Westerloo Aachen Department of Intensive Care

   Leiden University Medical Center

   Affiliation as printed

   Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands

6. Evert de Jonge corresponding Aachen Department of Intensive Care

   Leiden University Medical Center

   Affiliation as printed

   Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands. e.dejonge@lumc.nl

   Department of Intensive Care, Leiden University Medical Center, Leiden, The Netherlands