Evaluation of CT images
The Hounsfield units (HU) were measured in the DDFT (Fig. 1) and medial and lateral palmar digital arteries (Fig. 2) at the following sites: the upper level of the proximal sesamoid bone (1); the lower level of the proximal sesamoid bone (2); the middle level of the metacarpal bone (3); the level of the metacarpophalangeal joint (4). The region of interest (ROI) was manually drawn marginally for adjusting the size of the DDFT and arteries at the sites of interest. All the CT images were evaluated using a soft tissue algorithm (WW, 120 HU; WL, 400 HU), and reconstruction was performed with a 2 mm slice thickness and interval.