Assessment of manual and automated intracranial artery diameter measurements

Automated quantification of intracranial artery morphology facilitates the identification of risk predictors for aneurysm development, as well as the detection of aneurysms. One established risk factor is the diameter of intracranial arteries which are arranged in a circulatory anastomosis, called the Circle of Willis (CoW). In this work, we assessed the performance of manual and automated measurement of intracranial artery diameters. Au- tomated measurements were obtained using a full-width-at-half-maximum (FWHM) approach. We investigated intra-and inter-rater variability, and compared manual to automatically obtained diameter measurements. The displacement error of manual measurement was assessed as another source of intra-rater variation. We used Bland–Altman plots and intra-class correlation coefficient (ICC) for analysis. Overall, the assessment revealed acceptable variation in intra- and inter-rater variability with no proportional bias. The median displacement error for repeated manual measurements (intra-rater) was 0.55 mm (IQR 0.24 – 1.06 mm). Good agreement was found between manual and automated measurements, with an ICC value of 0.76 (p<0.05, Pearson). These findings have implications for future assessment of intracranial artery diameters.