An automated measurement of head circumference using CT scans: An application in children with head abnormalities

Manual measurement of head circumference has been a widely adopted method of neurodevelopmental evaluation in both clinical and research settings. Here, we propose a method that uses axial slices of computerized tomography (CT) scans to detect the largest outer margin for measurement. Our method can both complement conventional tape measurements or be applied as a standalone tool, especially in the context of retrospective big data analysis. We applied our algorithm in a set of 74 head CT scans obtained from individual children (8,5 ± 14,1 months old). The method proved to be concordant ( ICC [ 2 , k ] = 0.99 ) , consistent ( ICC [ 3 , k ] = 1), and showed a correlation of 0.988 compared to obtaining manual head circumferences by specialists. Our method is a reliable alternative to conventional manual measurements of head circumference. It can be readily applied in macrocephaly and microcephaly screening studies and in growth reference charts for syndromes related to head alterations. • We propose a automated pipeline for measuring head circumference (HC) directly from axial CT slices using only open-source tools. • The method includes a robust preprocessing strategy, including head alignment through rigid registration, slice selection filtering and adaptive contour extraction based on Hounsfield Unit thresholds. • We validate the proposed method on a heterogeneous pediatric dataset (n = 74) that includes both normocephalic and abnormal HC cases (microcephaly and macrocephaly), with images acquired from four distinct clinical centers with varying CT protocols and qualities. • The measure considers computed tomography imaging, which is an accessible technique in developing countries, where microcephalies of endemic etiologies are recurrent. • We provide dual validation of our method: (i) against manual measurements by two board-certified neuroradiologists using CT scans, and (ii) against head circumference measured clinically using a non-stretchable tape by an experienced pediatrician. • HC measurements obtained with our method showed high agreement, consistency, and correlation in comparison with manual HC measurements obtained by neuroradiologists, by using a head measuring tape and across consecutive evaluations. • We demonstrate the method's utility for retrospective clinical and public health applications, particularly in settings where CT scans are available but manual HC data is missing or unreliable.