In a clinimetric analysis, 3D stereophotogrammetry was found to be reliable and valid for measuring scar volume in clinical research

Objectives Volume is an important feature in the evaluation of hypertrophic scars and keloids. Three-dimensional (3D) stereophotogrammetry is a noninvasive technique for the measurement of scar volume. This study evaluated the reliability and validity of 3D stereophotogrammetry for measuring scar volume. Study Design and Setting To evaluate reliability, 51 scars were photographed by two observers. Interobserver reliability was assessed by the intraclass correlation coefficient (ICC), and the measurement error was expressed as limits of agreement (LoA). To assess validity, 60 simulated (clay) scars were measured by 3D stereophotogrammetry and subsequently weighed (gold standard). The correlation of volumes obtained by both measures was calculated by a concordance correlation coefficient (CCC), and the measurement error was expressed as a 95% prediction interval. Results The ICC was 0.99, corresponding to a high correlation of measurements between two observers, although the LoA were relatively wide. The correlation between 3D stereophotogrammetry and the gold standard was also high, with a CCC of 0.97. Again, the plot of the differences and LoA showed moderate agreement for the validity. Conclusion Three-dimensional stereophotogrammetry is suitable for the use in clinical research but not for the follow-up of the individual patient.