Using image J to document healing in ulcers of the foot in diabetes

The aim of the study was to assess the reliability of measuring the cross-sectional area of diabetic foot ulcers using Image J software. The inter- and intra-rater reliability of ulcer area measures were assessed using digital images of acetate tracings of ulcers of the foot affecting 31 participants in an off-loading randomised trial. Observations were made independently by five specialist podiatrists, one of whom was experienced in the use of Image J software and educated the other four in a single session. The mean (+/- SD) of the mean cross-sectional areas of the 31 ulcers determined independently by the five observers was 1386.7 (+/- 22.7) mm(2). The correlation between all pairs of observers was > 0.99 (P < 0.001). There was no significant difference overall between the five observers (ANOVA F1.538; P = 0.165) and no difference between any two (paired samples test t = -0.787-1.396; P >= 0.088). The correlation between the areas determined by two observers on two occasions separated by not less than 1 week was very high (0.997 and 0.999; P < 0.001 and < 0.001, respectively). The inter- and intra-reliability of the Image J software is very high, with no evidence of a difference either between or within observers. This technique should be considered for both research and clinical use in order to document changes in ulcer area.