Validating the Accuracy of the ‘Measurement of Baby's Head Shape<scp>™</scp>’ Mobile Application

In Japan, positional cranial deformities (PCD) have received limited attention. At present, objective evaluation of the severity of cranial deformity requires specialized equipment and software that are not suitable for screening. The ‘Measurement of a baby's head shape™’ (Japan Medical Company) application quantifies plagiocephaly and brachycephaly using mobile device images. However, the reliability and suitability of this application for screening PCD have yet to be verified. This study aimed to verify the reliability of the application and evaluate its suitability as a screening tool. Using 10 different head models created with a three‐dimensional (3D) printer, a total of 91 medical professionals examined 825 images using a mobile application to determine the severity of plagiocephaly and brachycephaly. Accuracy tests and measurement error factors were statistically analyzed. Regarding measurement error analysis, the shooting angle and distance information were obtained from four QR codes for the pedestal of the head model; the difference between the points specified by the application and design location (true value) was determined in 3D coordinate space. The sensitivity and specificity for plagiocephaly were 0.72 and 0.96, respectively, while for brachycephaly, they were 0.90 and 1.00. No statistically significant correlation was found between measurement errors and factors such as marking inaccuracies or occupational category. The “Measurement of a baby's head shape™” application could be used by medical professionals to perform cranial deformity screening following the measurement method guidelines when imaging is performed. © 2025 The Author(s). IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.