Fig. 1.

HR-pQCT image processing pipeline as published previously [26] and as now applied to the MCP 2 joint of a 55-year-old man who was diagnosed with HH at age 47. a Original coronal HR-pQCT image of the MCP 2 joint. Note the beak-like osteophyte at the metacarpal head (arrow). Figure 1 b, binarized image. After semi-automated contouring of the metacarpal bone and the adjacent proximal phalanx, the mineralized bone structure of both bones was automatically segmented from the grayscale image c Periosteal surface bone masks and the joint space mask d (in green) and e (in white) were then generated using several morphological image processing techniques. The joint space mask was then used to calculate all joint space related morphological parameters f Note the locally reduced joint space width as color-coded by dark green