Bone Mineral Density Derived from Cardiac CT Scans: Using Contrast Enhanced Scans for Opportunistic Screening

Andia Cheneymann; Josephine Therkildsen; Simon Winther; Louise Nissen; Jesper Thygesen; Bente L Langdahl; Ellen-Margrethe Hauge; Morten Bøttcher

doi:10.1016/j.jocd.2023.101441

Bone Mineral Density Derived from Cardiac CT Scans: Using Contrast Enhanced Scans for Opportunistic Screening

J Clin Densitom. 2024 Jan-Mar;27(1):101441. doi: 10.1016/j.jocd.2023.101441. Epub 2023 Nov 3.

Authors

Andia Cheneymann¹, Josephine Therkildsen², Simon Winther¹, Louise Nissen¹, Jesper Thygesen³, Bente L Langdahl⁴, Ellen-Margrethe Hauge², Morten Bøttcher⁵

Affiliations

¹ Department of Cardiology, Gødstrup Hospital, Herning, Denmark.
² Department of Rheumatology, Aarhus University Hospital, Aarhus Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
³ Department of Clinical Engineering, Aarhus University Hospital, Aarhus, Denmark.
⁴ Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Endocrinology, Aarhus University Hospital, Aarhus, Denmark.
⁵ Department of Cardiology, Gødstrup Hospital, Herning, Denmark; Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. Electronic address: morboett@rm.dk.

PMID: 38006641
DOI: 10.1016/j.jocd.2023.101441

Abstract

Purpose: Osteoporosis is under-diagnosed and often co-exists with other diseases. Very low bone mineral density (BMD) indicates risk of osteoporosis and opportunistic screening for low BMD in CT-scans has been suggested. In a non-contrast enhanced thoracic CT scan, the scan-field-of-view includes vertebrae enabling BMD estimation. However, many CT scans are obtained by administration of contrast material. If the impact of contrast enhancement on BMD measurements could be quantified, considerably more patients are eligible for screening.

Methods: This study investigated the impact of intravenous contrast on thoracic BMD measurements in cardiac CT scans pre- and post-contrast, including different contrast trigger levels of 130 and 180 Hounsfield units (HU). BMD was measured using quantitative CT with asynchronous calibration.

Results: In 195 participants undergoing cardiac CT (mean age 57±9 years, 37 % females) contrast increased mean thoracic BMD from 116±33 mg/cm³ (non-enhanced CT) to 130±38 mg/cm³ (contrast-enhanced CT) (p<0.001). Using clinical cut-off values for very low (<80 mg/cm³) and low BMD (<120 mg/cm³) showed that 24 % (47/195 participants) were misclassified when BMD was measured on contrast-enhanced CT-scans. Of the misclassified patients, 6 % (12/195 participants) were categorized as having low BMD despite having very low BMD on the non-enhanced images. Contrast-CT using a higher contrast trigger level showed a significant increase in BMD compared to the lower trigger level (119±32 vs. 135±40 mg/cm³, p<0.01).

Conclusion: For patients undergoing cardiac CT, using contrast-enhanced images to assess BMD entails substantial overestimation. Contrast protocol trigger levels also affect BMD measurements. Adjusting for these factors is needed before contrast-enhanced images can be used clinically.

Mini abstract: Osteoporosis is under-diagnosed. Contrast-enhanced CT made to examine other diseases might be utilized simultaneously for bone mineral density (BMD) screening. These scans, however, likely entails overestimation of BMD due to the effect of contrast. Adjusting for this effect is needed before contrast-enhanced images can be implemented clinically for BMD screening.

Keywords: Bone density; Contrast media; Diagnosis; Osteoporosis; X-Ray computed tomography.

MeSH terms

Absorptiometry, Photon / methods
Aged
Bone Density
Bone Diseases, Metabolic*
Female
Humans
Lumbar Vertebrae / diagnostic imaging
Male
Middle Aged
Osteoporosis* / diagnostic imaging
Retrospective Studies
Tomography, X-Ray Computed / methods