Computer aided detection of spinal degenerative osteophytes on sodium fluoride PET/CT

Abstract

Osteophytes, a common degenerative change in the spine, are found in 90% of the population over 60 years of age. We have developed an automated system to detect and assess spinal osteophytes on 18F-sodium fluoride (18F-NaF) PET/CT studies.We first segment the cortical shell of the vertebral body and unwrap it to a 2D map. Multiple characteristic features derived from PET/CT images are then projected onto the map. Finally, we adopt a three-tier learning based scheme to compute a confidence map and detect osteophyte sites and clusters. The system was tested on 20 studies (10 training and 10 testing) and achieved 84% sensitivity at 3.8 false positives per case for the training set, and 82% sensitivity at a 4.7 false positive rate for the testing set.