Image acquisition and processing. After immobilizing a subject's wrist and hand in a fixation splint (a), two scans are obtained from opposite view points and the scans are merged to create a three-dimensional (3D) model (b). Using the model, the center of a predefined region of interest (ROI) is selected and defined by the green box. Both wrist and metacarpalphalangeal (MCP) ROI boxes are shown. The ROIs can be isolated and the volume between the base of the ROI and the surface can be directly calculated using Rapidform software. The wrist is shown as an example (c). The distance in millimeters from the base of the ROI to the surface can be depicted as a color map in which blue represents a greater, and red a lesser, distance in millimeters from the base (d). In a similar manner, ROIs defining the wrist and MCP are selected from thermograms (e) and used to calculate the heat distribution index.
Spalding et al. Arthritis Research & Therapy 2008 10:R10 doi:10.1186/ar2360