[Chronic ulcers of the lower limbs: area evaluation by digital photography]

To evaluate results of digital imaging analysis in estimating the areas of chronic ulcers in the lower limbs.

In a prospective study the ulcer areas were estimated by the classic planimetric method, where ulcer perimeters are drawn on a transparent plastic film. Areas were then measured in millimetered paper. These values were considered as gold standards to evaluate standardized digital photographs of ulcers and of drawings for area estimation. A known length of adhesive was placed adjacent to ulcers to estimate the proportion of pixels relative to real millimeters.

Forty two lesions from 20 patients with chronic lower limb ulcers were evaluated. Areas ranged from 0.24 to 101.65cm2. Planimetric measures strongly correlated with photos of the ulcers (R(2)=0.86 p<0.01), however, their correlation with digital photos of the ulcer drawings was even higher (R(2)=0.99 p<0.01).

Standardized digital photography proved to be a quick, precise and non-invasive method to estimate ulcer areas. The evaluation of measurements from drawings of ulcer perimeters should be preferred to direct photographic analysis of the ulcers.