Assessment of the predictability of vertebral fractures in multiple myeloma in dual-layer CT (DLCT) with virtual non-calcium (VNCa) CT images and calculation of virtual calcium-only (VCa) images
Thuy Duong Do, Heidelberg / Germany
Author Block: S. Brandelik1, S. Rahn1, M. Merz2, W. Stiller1, S. Skornitzke1, C. Melzig1, H-U. Kauczor1, T. F. Weber1, T. D. Do1; 1Heidelberg/DE, 2Leipzig/DEPurpose: This study aimed to assess the predictability of vertebral fractures in multiple myeloma in dual-layer CT (DLCT) with virtual non-calcium (VNCa) CT images and the calculation of virtual calcium-only (VCa) images.Methods or Background: 81 patients with plasma cell dyscrasia and whole-body DLCT at the time of diagnosis and follow-up spine imaging were included in the study. Conventional CT images (CI), VNCa images with calcium suppression (CaSupp) indices 25 and 100, and the novel method of calculated VCa images by subtraction of CaSupp100 - CaSupp25 were quantitatively analysed using region-of-interests in the vertebral bodies L1-L5 and all vertebral bodies with fractures on baseline or follow-up imaging. Logistic regression analyses were performed to assess the predictability of imminent spine fractures. For model comparisons, the Akaike information criterion and R² were consulted.Results or Findings: New fractures were seen in 24 patients' follow-up imaging. Predictability of new vertebral fractures was significant for baseline assessment of CT numbers in CI, CaSupp 25 VNCa, and VCa (p=- 01, respectively) with a higher risk for new fractures in case of lower CT numbers in CI and VCa (Odds ratio 0.982 [0.969;0.994], 0.987 [0.978;0.995]) and in case of higher CT numbers in CaSupp 25 (Odds ratio 1.015 [1.006;1.026]). Direct model comparisons implied that CT numbers in CaSupp 25 and VCa might show better fracture prediction than in CI (R2=0.18 both vs. 0.15; AICc=91.95, 91.79 vs. 93.62). Neither age, gender nor pre-existing fractures improved the fracture predictability when included in the calculation.
Conclusion: VNCa and calculated VCa images in DLCT are feasible to predict imminent vertebral fracture risk in MM patients.Limitations: This study was limited by the number of patients.Funding for this study: No funding was received for this study.Has your study been approved by an ethics committee? YesEthics committee - additional information: This retrospective exploratory single-centre study was approved by the local review board (application number: S-348/2019). The need for written informed consent was waived.