Laser scanning as a tool for assessment of HIV-related facial lipoatrophy: evaluation of accuracy and reproducibility.

BACKGROUND

Facial lipoatrophy (LA) is a common complication of highly active antiretroviral therapy (HAART). Research into causes and treatment of facial LA is hindered by the lack of an objective measurement tool.

OBJECTIVE

To evaluate the accuracy and reproducibility of three-dimensional laser scanning (LS) for estimating cheek volume changes.

METHODS

Paired laser scans were performed and the images superimposed using commercial software. The volume difference between images was computed within a circle of radius 25 mm placed in a standardized position over the cheek area. Accuracy was tested by scanning before and after known volumes of plasticine (0.5--5 mL) were applied to the cheek area of a mannequin to simulate volume change. Reproducibility was tested by repeated scanning of the mannequin with and without 2 mL of plasticine, and repeated scanning of 10 healthy subjects over the course of 1 week.

RESULTS

The mean difference between actual and estimated volume change was small across the range of volumes tested [mean difference 0.08 mL; 95% confidence interval (CI)-0.36 to 0.20 mL). The coefficient of variation for repeated measurements of 2-mL volume change was 5.8%. The intraclass correlation coefficient for scan-to-scan variability was 0.812 (95% CI 0.515--0.947) and for day-to-day variability it was 0.764 (95% CI 0.332--0.935). Conclusions LS is an accurate and reproducible method for estimating cheek volume changes. It may be useful as an objective tool for assessment of facial LA in clinical research studies.