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

Abstract

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

Methods: 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.

Results: 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).

Conclusions: 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.