Automatic detection and tracking of longitudinal changes of multiple bone metastases from dual energy CT

Early detection and the assessment of changes in bone metastatic cancers can enable clinicians to monitor disease progression and modify treatment to help achieve improved results for patients. However, poor contrast makes detection difficult, and multiple disease sites make tracking of their changes over time difficult. We present a method for automatically detecting and tracking the longitudinal changes in multiple sclerotic bone metastases from Dual Energy Computed Tomography (DECT) images. We employ a multi-stage approach involving (i) bone and marrow extraction, (ii) slice-wise lesion candidate detection and volumetric segmentation, and (iii) aggregation of these 3D candidates. The algorithm achieved 78% agreement with radiologist identified lesions from 10 patients. Longitudinal consistency in the lesion detection computed over 26 scans using Williams' index was 1.02±0.23 using DICE and 1.03±0.30 using Hausdorff metrics. We also present preliminary results for analyzing lesion material composition changes by using a novel representation computed from the DECT images, where clear differences between bone metastases and normal marrow can be seen.