Radiological anatomical measurements of the superficial temporal artery: an interobserver reproducibility study

Purpose: Numerous studies have already reported on the anatomy of the superficial temporal artery (STA) on dissection or imaging, and more specifically on CT angiography. However, few studies have reported on the possible variations that exist between readers in the assessment of certain anatomical parameters. The aim of this study was to investigate the reproducibility of different anatomical measurements of the superficial temporal artery with CT angiography.

Methods: Forty cranial iodine contrast-enhanced CT scans were searched in a retrospective monocentric study. Various anatomical categorical and quantitative measurements (more or less automatic) of the superficial temporal artery were assessed. To evaluate the inter-observer reproducibility of various anatomical measurements of the superficial temporal artery obtained through CT angiography, descriptive statistics, kappa statistics and intraclass correlation coefficients (ICC) were employed.

Results: Eighty STAs were analyzed independently by two readers. The kappa coefficient for determining the mode of STA termination was substantial (kappa = 0.782). The number of loops was mean 0.22 vs. 0.25 (p = 0.981; ICC = 0.701) and the number of kinks was mean 5.68vs5.64 (p = 0.876; ICC = 0.860). No significant difference was found between readers for the determination of the distance of the STA termination to different superficial landmark lines. No significant difference in the orientation angles of the STA and the frontal and parietal branches was found. Semi-automatic measurements of the length of the STA appeared (ICC > 0.7) reproducible whereas semi-automatic measurements (surface, perimeter, short diameter, large diameter) appeared statistically less reproducible (ICC < 0.5). These results must also be interpreted in the light of the spatial resolutions inherent in the CT angiography technique.

Conclusion: The present study provides information concerning the reproducibility of certain anatomical measurements of the superficial temporal artery in CT angiography.