Semin Musculoskelet Radiol 2019; 23(S 01): S1-S6
DOI: 10.1055/s-0039-1687703
Scientific Presentations and Posters
Georg Thieme Verlag KG Stuttgart · New York

Accurate Opportunistic Vertebral Bone Mineral Density Measurements Based on Phantomless Routine Contrast-Enhanced Dual-Layer Spectral CT

Ferdinand Roski
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Johannes Hammel
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
4   Chair of Biomedical Physics & Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
,
Kai Mei
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Thomas Baum
2   Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Jan S. Kirschke
2   Department of Neuroradiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Daniela Pfeiffer
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Ernst J. Rummeny
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Peter B. Noël
3   Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, U.S.A.
,
Klaus Woertler
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Alexandra S. Gersing
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
,
Benedikt J. Schwaiger
1   Department of Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany
› Author Affiliations
Further Information

Publication History

Publication Date:
28 March 2019 (online)

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Objectives: To assess the value of opportunistic hydroxyapatite (HA)-specific vertebral bone mineral density (BMD) measurements derived from contrast-enhanced phantomless dual-layer spectral computed tomography (DLCT) examinations.

Methods: On DLCT examinations of 133 patients (63 ± 16 years; 32% women), volumes of interest were placed in three thoracolumbar vertebral bodies. Hounsfield unit (HU) and HA-specific BMD values for noncontrast-enhanced (NE), arterial (AR), and portal venous (PV) phases were extracted from conventional and virtual monoenergetic images (50 and 200 keV). HU and iodine densities were also measured in the abdominal aorta (AA), inferior vena cava, and vena portae (VP) on each CT phase. Multivariable linear regression models with forward selection were used to identify optimal conversion equations to convert density measurements in AR and PV phases to HA-specific BMD measurements (cBMD) in NE as a reference standard.

Results: AR-BMD (mean ± SD: 115.15 ± 48.36 mg/mL) and PV-BMD (128.21 ± 47.32 mg/mL) showed significant correlations (r = 0.994 and r = 0.989; p < 0.001 for each correlation) but a low agreement with NE-BMD (105.68 ± 46.83 mg/ml). Linear regression models using NE-BMD as a criterion variable revealed an R2 adj = 0.991 for AR and an R2 adj = 0.986 for PV. Vessel iodine concentrations (ICs) were identified as significant covariates [AR: VP-IC, R2change (R2c) = 0.003 (p < 0.001), AA-IC, R2c = 0.000 (p < 0.05); PV: AA-IC, R2c = 0.007 (p < 0.001), VP-IC, R2c = 0.002 (p < 0.001)] and were included in phase-specific conversion equations [AR: cBMD = − 1.212 + 0.981*(AR-BMD) − 1.861*(VP-IC) − 0.262*(AA-IC); PV: cBMD = − 4.181 + 0.986*(PV-BMD) − 1.323*(AA-IC) − 1.694*(VP-IC)].

Conclusion: Converted HA-specific BMD measurements in arterial and portal venous phases adjusted for iodine concentrations obtained from abdominal vessels showed a high agreement with HA-specific BMD from non-enhanced CT, suggesting their potential value for a reliable assessment of BMD using routine contrast-enhanced DLCT examinations.