Rapid study assessment in follow-up whole-body computed tomography in patients with multiple myeloma using a dedicated bone subtraction software

M.M. Sieren, F. Brenne, A. Hering, H. Kienapfel, N. Gebauer, T.H. Oechtering, A. Fürschke, F. Wegner, E. Stahlberg, S. Heldmann, J. Barkhausen and A. Frydrychowicz

European Radiology



Objectives The diagnostic reading of follow-up low-dose whole-body computed tomography (WBCT) examinations in patients with multiple myeloma (MM) is a demanding process. This study aimed to evaluate the diagnostic accuracy and benefit of a novel software program providing rapid-subtraction maps for bone lesion change detection. Methods Sixty patients (66 years +- 10 years) receiving 120 WBCT examinations for follow-up evaluation of MM bone disease were identified from our imaging archive. The median follow-up time was 292 days (range 200-641 days). Subtraction maps were calculated from 2-mm CT images using a nonlinear deformation algorithm. Reading time, correctly assessed lesions, and disease classification were compared to a standard reading software program. De novo clinical reading by a senior radiologist served as the reference standard. Statistics included Wilcoxon rank-sum test, Cohen's kappa coefficient, and calculation of sensitivity, specificity, positive/negative predictive value, and accuracy. Results Calculation time for subtraction maps was 84 s +- 24 s. Both readers reported exams faster using subtraction maps (reader A, 438 s +- 133 s; reader B, 1049 s +- 438 s) compared to PACS software (reader A, 534 s +- 156 s; reader B, 1486 s +- 587 s; p < 0.01). The course of disease was correctly classified by both methods in all patients. Sensitivity for lesion detection in subtraction maps/conventional reading was 92%/80% for reader A and 88%/76% for reader B. Specificity was 98%/100% for reader A and 95%/96% for reader B. Conclusion A software program for the rapid-subtraction map calculation of follow-up WBCT scans has been successfully tested and seems suited for application in clinical routine. Subtraction maps significantly facilitated reading of WBCTs by reducing reading time and increasing sensitivity.