The normal internal carotid artery: a computed tomography angiographic study.

Area of Science:

• Vascular imaging
• Radiology
• Cerebrovascular anatomy

Background:

• Systematic computed tomography angiographic (CTA) studies on internal carotid artery (ICA) luminal diameter (LD) variation are limited.
• Understanding normal intra-individual LD variability is key for detecting subtle carotid collapses.
• Consistent contralateral LD measurements can aid in stenosis estimation when ipsilateral data is compromised.

Purpose of the Study:

• To investigate the intra-individual variation of normal internal carotid artery (ICA) luminal diameters (LDs).
• To establish a baseline for normal LD variability in the ICA.
• To assess the potential of using contralateral measurements for stenosis evaluation.

Main Methods:

• Retrospective analysis of multidetector high-speed CTAs from 104 patients under 40 without carotid pathology.
• Independent bilateral measurements of common carotid artery (CCA) and ICA LDs by two observers.
• Paired t-test analysis of side-to-side LD differences using averaged measurements.

Main Results:

• No significant side-to-side differences were found in ICA or CCA LDs.
• Mean ICA LD difference in females was 0.03 mm (95% CI: -0.04, 0.11) with a standard deviation of 0.4 mm.
• Mean ICA LD difference in males was 0.02 mm (95% CI: -0.07, 0.11) with a standard deviation of 0.4 mm. No ICA agenesis was detected.

Conclusions:

• The intrinsic intra-individual variation in normal internal carotid artery (ICA) luminal diameter (LD) is minimal.
• This uniformity provides a basis for identifying subtle pathological side-to-side variations.
• Findings support the use of contralateral ICA LD as a reference in specific clinical scenarios.