The normal internal carotid artery: a computed tomography angiographic study

Morphometry of the Entire Internal Carotid Artery on CT Angiography

Background and Objectives: Knowledge of the internal carotid artery’s (ICA) morphometric features is influential in outlining surgical and minimally invasive procedures in the neurovascular field. Many studies have shown divisive numbers regarding the ICA’s caliber, with the measuring point of the artery sometimes differing. This study presents ICA dimensions based on computed tomography angiography in each of its seven segments as per Bouthillier’s classification, correlating vascular dimensions with anthropometric parameters. Materials and Methods: A thorough CT angiography analysis was performed on 70 patients with internal carotid vessels unaffected by atherosclerotic disease. The extracranial part of the ICA was measured in four locations—carotid bulb, post-bulbar dilation, at its cervical midpoint, and below its entrance into the carotid foramen. Single landmarks were used for measurements in the intracranial segments. ICA length was assessed in the neck region and also in the cranial cavity. Craniometric measurements were performed on sagittal and coronal CT reconstructions. Patient height was taken into consideration. Results: The largest ICA portion is near its origin in the carotid sinus area (7.59 ± 1.00 mm), with a steep decline in caliber following its extracranial course. Distal ICA presented values somewhat similar to its proximal intracranial segment diameters (4.67 ± 0.47 mm). Dimensions of the ICA in the intracranial segments start from a value of 4.53 ± 0.47 mm and decrease by approximately 40% when reaching the origin of the middle cerebral artery (2.71 ± 0.37 mm), showing a marked decrease in caliber after the emergence of the most critical collateral artery, the ophthalmic branch. The length of the ICA varies between genders, with the male ICA being about 10 mm longer in total length than female ICA; this difference is also correlated with patient height and skull dimensions. Conclusions: Both intra- and extracranial ICA have variable dimensions and length related to gender and anthropometric parameters, with no significant differences obtained concerning side or age.

Inner diameters of the normal carotid arteries measured using three-dimensional digital subtraction catheter angiography: a retrospective analysis

Purpose

To obtain normal ranges for the inner diameters of the carotid arteries.

Methods

This retrospective analysis included consecutive patients with disease-free carotid arteries who had undergone 3D-DSA at two hospitals in Nanning, Guangxi, between March 2013 and March 2018. Demographic and clinical characteristics, including Essen Stroke Risk Score (ESRS), were extracted from the medical records. The 3D-DSA data were used to calculate the inner diameters of the carotid arteries.

Results

The analysis included 1182 patients (837 males) aged 58.81 ± 11.02 years. The inner diameters of the proximal carotid sinus (CS), CS bulge, distal CS, and common carotid artery (CCA) were larger on the right than on the left (P < 0.05). The inner diameters of the proximal CS, CS bulge, distal CS, and CCA on both sides were larger for males than females (P < 0.05). The inner diameters of the proximal CS, CS bulge, and distal CS on both sides were smaller for patients aged > 65 years than for patients aged ≤ 55 years (P < 0.05). Right CCA inner diameter did not vary with age, whereas left CCA inner diameter was larger for patients aged > 55 years than for patients aged ≤ 45 years (P < 0.05). The inner diameters of the proximal CS, CS bulge, and distal CS on both sides were smaller for patients with ESRS ≥ 3 than those with ESRS < 3 (P < 0.05).

Conclusion

This study provides reference values for the internal diameters of normal carotid arteries. Carotid artery diameters varied with side, sex, and age.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02328-z.

Warfarin Treatment Is Associated to Increased Internal Carotid Artery Calcification

Background: Long-term treatment with the vitamin K antagonist warfarin is widely used for the prevention of venous thrombosis and thromboembolism. However, vitamin K antagonists may promote arterial calcification, a phenomenon that has been previously studied in coronary and peripheral arteries, but not in extracranial carotid arteries. In this observational cohort study, we investigated whether warfarin treatment is associated with calcification of atherosclerotic carotid arteries.

Methods: Overall, 500 consecutive patients underwent carotid endarterectomy, 82 of whom had received long-term warfarin therapy. The extent of calcification was assessed with preoperative computed tomography angiography, and both macroscopic morphological grading and microscopic histological examination of each excised carotid plaque were performed after carotid endarterectomy.

Results: Compared with non-users, warfarin users had significantly more computed tomography angiography-detectable vascular calcification in the common carotid arteries (odds ratio 2.64, 95% confidence interval 1.51–4.63, P < 0.001) and even more calcification in the internal carotid arteries near the bifurcation (odds ratio 18.27, 95% confidence interval 2.53–2323, P < 0.001). Histological analysis revealed that the intramural calcified area in plaques from warfarin users was significantly larger than in plaques from non-users (95% confidence interval 3.36–13.56, P = 0.0018).

Conclusions: Long-lasting warfarin anticoagulation associated with increased calcification of carotid atherosclerotic plaques, particularly in locations known to be the predilection sites of stroke-causing plaques. The clinical significance of this novel finding warrants further investigations.

[Ct-angiography in assessment of critical occlusive carotid artery disease]

BACKGROUND

Occlusive carotid artery disease is still one of the major causes of ischemic stroke in the world. Progression of severe carotid stenosis may lead to critical stenosis and vascular occlusion. Nevertheless, there is still no pure definition of the concept of critical occlusive carotid artery disease.

OBJECTIVE

To define the role of CT-angiography in assessment of critical occlusive carotid artery disease.

MATERIAL AND METHODS

We analyzed data of 405 patients who underwent preoperative precise assessment of carotid arteries and subsequent surgical treatment for the period from 2016 to 2019. Contrast-enhanced CT-angiography (Philips Ict scanner, 256 slices) was made after previous ultrasound. Contrast agent injection rate was 4-5 ml/sec. CT angiography data were assessed according to a specialized protocol.

RESULTS

Critical occlusive carotid artery disease was observed in 128 (31.6%) cases including critical stenosis (24.94%), near-occlusion (5.92%) and local occlusion (0.74%). Critical stenosis was characterized by local narrowing ≥90% and normal diameter of distal arterial segment. In case of near-occlusion, local critical stenosis was accompanied by narrowing of distal arterial segment. In case of local occlusion, distal collateral supply of internal carotid artery occurred through atypically originating ascending pharyngeal artery. Patients with near-occlusion and local occlusion of internal carotid artery had no signs of ICA hypoplasia and intracranial stenoses. All elements of circle of Willis were observed in 70% of patients.

CONCLUSION

State of distal segment of internal carotid artery can be considered as a differential diagnostic criterion for critical occlusive carotid disease variants. CT-angiography provides all necessary data and can be recommended for precise preoperative assessment.

An unusual variation of carotid-vertebrobasilar arteries: An anatomical case report

BACKGROUND AND PURPOSE

Having no obvious clinical symptoms and signs, it is difficult to find head and neck vascular variations without the aid of vascular imaging techniques.

SUMMARY OF CASE

A 66-year-old female patient underwent head and neck computed tomographic angiography examination. Her computed tomographic angiography examination revealed that the internal carotid artery directly migrated to the ophthalmic artery. Brain blood supply is provided by the vertebrobasilar artery independently.

CONCLUSION

To the best of the author's knowledge, this is a very rare anatomical vascular variation of the head and neck found by computed tomographic angiography.