RHEUMATOID ARTHRITIS EROSION DETECTION AND MEASUREMENT IN LONGITUDINAL DATASETS USING HIGH-RESOLUTION PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY (HR-PQCT): RELIABILITY EXERCISE-2 (RELEX-2)

Abstract

Background An operational case definition for identification of erosions imaged by HR-pQCT was achieved and tested in a first reliability exercise (RELEX-1) using cross-sectional data. Objectives To test the case definition and define landmarks for measurement of erosion size in 2D in a longitudinal dataset. Methods Patients meeting classification criteria for RA at various stages of disease duration and severity had HR-pQCT scans of the 2nd and 3rd MCP joints at 0 and 12 month timepoints. Standard image acquisition and segmentation was performed for a 2.7 cm scan area. Images are evaluated for erosions at 8 surfaces per joint (ulnar, radial, dorsal, palmar surfaces of the proximal phalanx a..