Digital Imaging
Research Objectives:
The purpose of this study was to determine the ability of physicians to track the progress of patients’ acne using digital images taken by the patients themselves.
Drivers:
Technology offers new ways to deliver care to dermatology patients. Digital images and clinical information can be transferred from patient to clinician over the Internet allowing asynchronous, remote assessment. Acne patients are well-suited to this approach given that they are generally technologically able, require ongoing follow-up but have a non-malignant condition. The ability of physicians to assess acne severity using such images, however, has not been validated.
Study Overview:
20 subjects were recruited from an ongoing clinical study into facial acne. Each patient had 5 study visits, at 6 weekly intervals. At each visit, sets of three images (front and both sides) were obtained. Half of the subjects were asked to take their own images, following a brief training session. The remaining 10 subjects had all images taken by study staff. In total 300 images were included in this analysis. All images were assessed by two dermatologists using 4 validated acne assessment measures: the Acne Lesion Count, Leed’s Assessment Score, Investigator’s Global Assessment, and a Forced choice evaluation. In addition, a non-medical photographer rated the quality of the images using the Q-index. All assessors were blinded to the time-point of the image and to who had taken the image.
Results:
The mean age of participants was 26 years old (SD 5.84, range 16-40) and the majority (90%) were female. Image Quality differed between subjects taking their own photos at home compared to study staff taking the photos of subjects in the office. The mean (SD) quality of images taken by subjects was 1.77 (1.31) compared to 2.5 (1.27) for study staff. Despite a low image quality, the raters were able to assess over 86% of the images for every acne assessment measure. Intra-rater reliability estimates for the two raters were highest for the Lesion Counts and Investigator Global Assessment. Inter-rater agreement for the different assessment measures was highest for Lesion Counts. There was low agreement between the two raters for the Forced Choice (40%).
The majority of digital images allowed an assessment of acne severity to be made. Patients appear able to self-image although their images may be of lower quality than those obtained in clinic. High Inter-rater agreement on acne lesion counts, using digital images, is consistent with in-person agreement rates reported in the literature. This indicates that remote management of acne may be a practical management strategy for dermatologists.