Internal Carotid Artery Angle Research Articles

Factors associated with the laterality of Cardio-Embolic stroke

ObjectiveUnderstanding the lateralization factors, including the anatomic and hemodynamic mechanisms, is essential for diagnosing cardio-embolic stroke. This study aims to investigate the elements, for the first time together, that could affect the laterality of stroke. MethodsWe performed a monocentric retrospective case-control study based on prospective registries of acute ischemic stroke patients in the comprehensive stroke center of the RWTH University hospital of Aachen for three years (June 2018–June 2021). We enrolled 222 patients with cardioembolic stroke (136 left stroke and 86 right stroke) admitted for first-ever acute ischemic stroke with unilateral large vessel occlusion of the anterior circulation. The peak systolic velocity (PSV) asymmetry of middle cerebral artery (MCA) was assessed by doppler as well as internal carotid artery (ICA) angle, aortic arch (AA) branching pattern and anatomy were assessed by CT-Angiography. ResultsWe found that the increasing left ICA angle (p = 0.047), presence of bovine type AA anatomy (p = 0.041) as well as slow PSV of the right MCA with a value of >15% than left (p = 0.005) were the predictors for left stroke lateralization, while the latter was an independent predictor for the left stroke (OR=3.341 [1.415–7.887]). Inter-Rater Reliability ranged from moderate to perfect agreement. ConclusionThe predictors for left stroke lateralization include the higher values of left ICA angle, presence of the bovine type AA and the slow right MCA PSV.

Association between Carotid Bifurcation Angle and Vulnerable Plaque Volume Using Black Blood Magnetic Resonance Imaging.

The morphology of the internal carotid artery (ICA) bifurcation is increasingly being recognized as the cause of atherosclerosis and vulnerable plaque leading to cerebral infarction. In this study, we investigated the relationship between carotid bifurcation angle and carotid plaque volume evaluated using black blood magnetic resonance imaging (BB-MRI). Among the 90 patients who underwent revascularization for atherosclerotic symptomatic carotid stenosis between April 2016 and October 2022 using BB-MRI, carotid plaque was evaluated in 57 patients. Relative overall signal intensity (roSI) was defined as the signal intensity of the plaque on T1-weighted images relative to the signal intensity of the sternocleidomastoid muscle in the same slice as the common carotid bifurcation. Regions showing roSI ≥ 1.0 were defined as plaque, and the plaque volume and relative plaque volume were measured from roSI ≥1.0 to ≥2.0 in 0.1 increments. We calculated the angles between the common carotid artery (CCA) and the ICA and between the CCA and the external carotid artery (ECA) on magnetic resonance angiography. We classified two groups according to carotid bifurcation angles based on the ICA angle: Group A = <35° and Group B = ≥35°. Compared with Group A (n = 42), Group B (n = 15) showed a greater relative plaque volume between roSI ≥ 1.3 and roSI ≥ 1.5. A significant correlation was identified between relative plaque volume with roSI ≥ 1.4 and ICA angle (p = 0.049). Vulnerable plaque was significantly more frequent in the group with an ICA angle of ≥35. Moreover, the ICA angle was significantly greater in patients with a roSI of ≥1.4.

Deep Learning-based Assessment of Internal Carotid Artery Anatomy to Predict Difficult Intracranial Access in Endovascular Recanalization of Acute Ischemic Stroke

BackgroundEndovascular thrombectomy (EVT) duration is an important predictor for neurological outcome. Recently it was shown that an angle of ≤ 90° of the internal carotid artery (ICA) is predictive for longer EVT duration. As manual angle measurement is not trivial and time-consuming, deep learning (DL) could help identifying difficult EVT cases in advance.MethodsWe included 379 CT angiographies (CTA) of patients who underwent EVT between January 2016 and December 2020. Manual segmentation of 121 CTAs was performed for the aortic arch, common carotid artery (CCA) and ICA. These were used to train a nnUNet. The remaining 258 CTAs were segmented using the trained nnUNet with manual verification afterwards. Angles of left and right ICAs were measured resulting in two classes: acute angle ≤ 90° and > 90°. The segmentations together with angle measurements were used to train a convolutional neural network (CNN) determining the ICA angle. The performance was evaluated using Dice scores. The classification was evaluated using AUC and accuracy. Associations of ICA angle and procedural times was explored using median and Whitney‑U test.ResultsMedian EVT duration for cases with ICA angle > 90° was 48 min and with ≤ 90° was 64 min (p = 0.001). Segmentation evaluation showed Dice scores of 0.94 for the aorta and 0.86 for CCA/ICA, respectively. Evaluation of ICA angle determination resulted in an AUC of 0.92 and accuracy of 0.85. ConclusionThe association between ICA angle and EVT duration could be verified and a DL-based method for semi-automatic assessment with the potential for full automation was developed. More anatomical features of interest could be examined in a similar fashion.

Internal carotid artery position to characterize risk for vessel injury in pediatric intraoral trauma.

The internal carotid artery (ICA) lies in close anatomic proximity to the oropharynx and is at risk for injury in the instance of intraoral trauma. The objectives of this study are to describe the position of the ICA relative to the oropharynx and identify patient risk factors related to its position. A total of 100 patients aged 12 months to 7 years 11 months who received computed tomography (CT) of the neck were randomly selected. The position of the ICA was determined by measuring its angular location relative to the center of the oropharynx (ICA angle) and the shortest distance from the oropharyngeal surface (OP-ICA distance). Indication for imaging was controlled for in all reported data. Patient age was related to ICA angles on both the left (F=8.06; P=0.01; η2=0.08, 95% CI: 0.01-0.19) and right (F=18.62; P<0.001; η2=0.17, 95% CI: 0.05-0.29). Patient weight also was related to ICA angles on both the left (F=7.08; P=0.01; η2=0.07, 95% CI: 0.01-0.18) and right (F=11.86; P<0.001; η2=0.11, 95% CI: 0.02-0.24). Patient age was related to the left OP-ICA distance (F=7.36; P=0.01; η2=0.07, 95% CI: 0.01-0.19), as was patient weight (F=4.82; P=0.03; η2=0.05, 95% CI: 0.00-0.15). Across all measurements, no significant relationship was identified between ICA position and other patient variables, including sex and race/ethnicity. The ICA of younger patients and those with lower body weight may be located more medially within the neck and closer to the oropharyngeal surface. This vessel position may place these children at greater anatomic susceptibility for ICA injury in the event of intraoral trauma.

Clinical Implications of Internal Carotid Arterial Tortuosity in Patients with White Matter Hyperintensities

AbstractBackgroundWhite matter hyperintensities (WMHs) are observed frequently on MRI in elderly and associated with cognitive dysfunction. Many studies focused on intracranial small vessel disease (SVD), however, few studies linked WMHs with changes of extracranial large feeding arteries. We aimed to investigate the effects of internal carotid artery (ICA) tortuosity changes through quantitative MR Angiography.MethodFifty‐seven patients (age: 72.98±5.62; 32 females/25 males) with WMHs were included. WMHs lesions were semi‐automatically segmented on FLAIR images. ICAs were segmented on the TOF images to generate tortuosity quantitative metrics, including tortuosity index (TI), inflection count metric (ICM), and ICA angle (Figure 1). According to the Fazekas scores, patients were categorized into mild, moderate and severe groups as summarized in Table 1. One‐way ANOVA analyses were applied to reveal the difference of averaged bilateral ICAs' tortuosity measurements. Pearson's correlation coefficients were calculated to quantitatively investigate the relationship between tortuosity and volumes of lesions that are apart from the ventricle in subcortical white matter, i.e., deep white matter lesions (DWMLs), as well as the lesions attached with the ventricular system, i.e., periventricular white matter lesions (PVWMLs).ResultPatients with higher Fazekas scores have higher TI and ICM, indicating higher tortuosity (Figure 2). The correlation results showed that TI and ICM were positively correlated with DWMLs volumes (r = 0.33, P&lt; 0.05; r = 0.4, P&lt; 0.01), however, they did not show associations with PVWMLs. While there's no correlation between averaged bilateral ICA angles and DWMLs or PVWMLs, we found significant correlations between left ICA angles and DWML volumes on left brain (r =0.56, P &lt; 0.005) as well as between right ICA angles and DWML volumes on right brain (r = 0.49, P &lt; 0.05) (Figure 3).ConclusionTortuosity measurements derived from TOF images showed that subjects with higher degree of ICA tortuosity had higher lesion volumes of DWMLs not PVWMLs, indicating DWMLs may have different etiologies such as ischemic origin. The findings also highlight the importance of ICA angle as a risk factor for WMHs development which might be associated with the local hemodynamic shear stress at the bulb, where the ICA plaques are often developed.

Internal Carotid Artery Angle Variations are Poorly Explained by Vascular Risk Factors: The Northern Manhattan Study

ObjectivesThe internal carotid artery (ICA) angle of origin may contribute to atherogenesis by altered hemodynamics. We aim to determine the contribution of vascular risk factors and arterial wall changes to ICA angle variations. MethodsWe analyzed 1,065 stroke-free participants from the population-based Northern Manhattan Study who underwent B-mode ultrasound (mean age 68.7±8.9 years; 59% women). ICA angle was estimated at the intersection between the common carotid artery and the ICA center line projections. Narrower external angles translating into greater carotid bifurcation bending were considered unfavorable. Linear regression models were fitted to assess the relationship between ICA angle and demographics, vascular risk factors, and arterial wall changes including carotid intima-media thickness (cIMT) and plaque presence. ResultsICA angles were narrower on the left compared to the right side (153±15.4 degrees versus 161.4±12.7 degrees, p<0.01). Mean cIMT was 0.9±0.1 mm and 54.3% had at least one plaque. ICA angle was not associated with cIMT or plaque presence. Unfavorable left and right ICA angles were associated with advanced age (per 10-year increase β=-1.6; p=0.01, and -1.3; p=0.03, respectively) and being Black participant (β=-4.6; p<0.01 and -2.9; p=0.04, respectively), while unfavorable left ICA angle was associated with being female (β=-2.8; p=0.03) and increased diastolic blood pressure (per 10 mmHg increase β=-2.1; p<0.01). Overall, studied factors explained less than 10% of the variance in ICA angle (left R2=0.07; right R2=0.05). ConclusionOnly a small portion of ICA angle variation were explained by demographics, vascular risk factors and arterial wall changes. Whether ICA angle is determined by other environmental or genetic factors, and is an independent risk factor for atherogenesis, requires further investigation.

Relationship Between Carotid Artery Angle and Plaque Morphology in Acute Cerebral Infarction Patients.

Background:High-resolution magnetic resonance imaging (HRMRI) can be used to clearly distinguish the luminal structure of the carotid artery (CA); measure the lumen, vessel wall, and total blood vessel area; and accurately describe the morphologic features of plaques.Methods:This study used HRMRI to investigate the relationship between geometric features and volume and composition of carotid atherosclerotic plaques. Patients (n=81) who had experienced acute cerebral infarction (CI) within 7±3 days before admission to the Neurology Department of Beijing Tiantan Hospital between November 2011 and June 2012 were enrolled in the study. CA HRMRI was performed to analyze the geometry and morphology of plaques in 160 blood vessels.Results:The median left and right internal carotid artery angles (ICAAs) were 32.79 and 31.00 degrees, respectively. Aside from the nonplanar external CA angle, plaque volume and angles did not differ significantly between the left and right sides. Age (B=3.77; P=0.03) and nonplanar ICAA (B=4.70; P=0.01) were predictors of left but not right carotid plaque volume. ICAA and bifurcation angle did not predict plaque volume.Conclusions:In this study, CA morphology in acute stroke patients is not associated with plaque volume or composition, but age and nonplanar ICAA can predict left carotid plaque volume.

Evaluation of Plaque Vulnerability via Combination of Hemodynamic Analysis and Simultaneous Non-Contrast Angiography and Intraplaque Hemorrhage (SNAP) Sequence for Carotid Intraplaque Hemorrhage.

The purpose of this study was to assess the vulnerability of plaque using a combination of simultaneous non-contrast angiography, intraplaque hemorrhage (SNAP) sequence, and local hemodynamic analysis in an intraplaque hemorrhage (IPH), and to evaluate the association between morphological and hemodynamic factors and IPH by comparing the IPH (presence of IPH) and non-IPH (plaque with absence of IPH) groups. In total, 27 IPH patients and 27 non-IPH patients were involved in this study, and baseline characteristics were collected. For morphological factors, diameters, and areas of the internal carotid artery (ICA), external carotid artery, and common carotid artery were measured, and bifurcation angle (α) and ICA angle (β) were also measured for comparison between the IPH group and non-IPH group. For hemodynamic factors, time-averaged wall shear stress (WSS), minimum WSS, maximum WSS, and oscillatory shear index were calculated using computational fluid dynamics (CFD) simulations. For the qualitative analysis, cross-sectional images with analyzed WSS and SNAP sequences were combined to precisely assess local hemodynamics. Bifurcation angle (α) was significantly different between the IPH and non-IPH groups (39.47 degrees vs. 47.60 degrees, p = 0.041). Significantly higher time-averaged WSS, minimum WSS, and maximum WSS were observed in the IPH group compared to the non-IPH group. In the IPH group, when using the combined analysis with SNAP sequences and WSS, the WSS of the region with IPH was significantly higher than the region without IPH (2.32 vs. 1.21 Pa, p = 0.005). A smaller bifurcation angle (α) and higher time-averaged WSS, minimum WSS, and maximum WSS were associated with IPH. The combined analysis of SNAP sequences and WSS might help to evaluate the risk of carotid IPH.

Abstract P647: Variations in the Internal Carotid Artery Angle of Origin Are Poorly Explained by Vascular Risk Factors

Background: Internal carotid artery (ICA) angle of origin is considered a contributor to atherogenesis because of its influence on hemodynamics. It is controversial if ICA angle variations are causal or consequential to carotid atherosclerosis or vascular risk factors. We aim to determine whether vascular risk factors underly ICA angle interindividual variations. Methods: The study included 1,111 stroke-free participants of the population-based Northern Manhattan Study (NOMAS) who underwent ICA angle estimation using B-mode carotid ultrasound (mean age 68.7±8.9 years; 41% were men, 60% Hispanic, 21% Black, and 18% White). Multivariable linear regression models were fit to assess the relationship of ICA angle to vascular risk factors. Results: ICA angle was significantly wider on the left compared to the right (26.6 ±15.5 degrees versus 18.6 ±12.9 degrees; p&lt;0.001). In multivariate analyses, left ICA angle was correlated with age (B=0.07; p=0.03), female sex (B=0.09; p=0.004), Black race (B=0.11; p=0.02), and diastolic blood pressure (B=0.16; p&lt;0.001), whereas right ICA angle was positively correlated with body mass index (B=0.07; p=0.04) and physical inactivity (B=0.08; p=0.02), and inversely correlated with low-density lipoprotein level (B=-0.1; p=0.004). Overall, these factors explained less than 5% of ICA angle variance (R 2 =0.0399 on the left; R 2 =0.0197 on the right). Conclusion: ICA angle variations are poorly explained by vascular risk factors at the population level. Our results suggest ICA angle is an independent feature that may predispose to atherogenesis.

Endovascular Treatment for Lateral Wall Paraclinoid Aneurysms and the Influence of Internal Carotid Artery Angle.

Lateral wall paraclinoid aneurysms (LPA) are a rare type of aneurysm located on the lesser curve side of the internal carotid artery (ICA) bend, at the level of the anterior clinoid process. The objective of this study was to assess the influence of flexion of the ICA on the morphology of aneurysms and outcome of endovascular treatment. Between 2003 and 2018, we treated 643 cases of unruptured paraclinoid aneurysms with endovascular therapy in our institution. Of those cases, aneurysms projecting laterally on preoperative angiography were defined as LPA. The degree of bending of the ICA (ICA angle) was measured and statistically analyzed in relation to the aneurysm characteristics and the occlusion status after treatment. In all, 43 aneurysms were identified. ICA angle was positively correlated with the maximum dome size of the aneurysm (P <0.01) and the aspect ratio (P <0.01), and negatively correlated with the volume coil embolization ratio (P <0.01). Complete occlusion (CO) was achieved in 23 cases (53.5%) immediately after treatment, and in 35 cases (81.4%) at follow-up. The mean ICA angle in the incomplete occlusion group was significantly larger than in the CO group (P = 0.01). Larger ICA angle resulted in recurrence, whereas smaller ICA angle was more likely to obtain progressive thrombosis (P = 0.02). Endovascular treatment for LPA was safe and effective. The degree of flexion of the ICA may contribute to the level of hemodynamic stress on the aneurysm, its morphology, and the embolization effect.

Atherosclerotic plaque locations may be related to different ischemic lesion patterns

BackgroundAtherosclerosis of the internal carotid artery (ICA) is an important cause of ischemic stroke. Artery-to-artery embolism is the major stroke mechanism in patients with atherosclerotic carotid disease. This study hypothesized that the atherosclerotic ICA geometry and plaque location would be associated with lesion pattern in patients with acute ischemic stroke.MethodsIschemic stroke patients with symptomatic proximal ICA disease (> 50% diameter stenosis) were enrolled. The carotid plaque location was divided into high-apical and low-body types. The geometric parameters of the ICA (angles between arteries) were measured, and ischemic lesion patterns were classified according to the number, location, and size of the lesions. Factors associated with plaque location and lesion pattern, dichotomized by size, were investigated.ResultsOf the 93 acute ischemic stroke patients enrolled, 31 had high-apical and 62 had low-body plaques. Hyperlipidemia was more prevalent and the common carotid artery (CCA)-ICA angle was wider (167.7 ± 10.4° vs 162.3 ± 9.8°, p = 0.019) in patients with low-body than high-apical plaques. Low-body plaques were more frequently associated with small scattered or cortical lesions (54.8% vs. 32.3%, p = 0.040), whereas high-apical plaques were more frequently associated with large lesions having additional lesions (38.7% vs. 11.3%, p = 0.002). The presence of low-body plaques (odds ratio: 3.106, 95% confidence interval: 1.105–8.728, p = 0.032) was independently associated with the small lesion-only pattern.ConclusionsLow-body plaques are more frequently associated with small scattered lesions, whereas high-apical plaques are more frequently associated with large lesions having additional lesions. A wide CCA-ICA angle is associated with low-body plaque of the carotid artery.

Surgical Management of Posterior Communicating Artery Aneurysms in the Presence of a Low-Coursing Internal Carotid Artery and Narrowed Retrocarotid Window

Anatomical variations of the course of the internal carotid artery (ICA) may complicate surgical clipping of posterior communicating artery (PCoA) aneurysms by narrowing the retrocarotid window. We evaluated the efficacy of the periclinoid surgical maneuvers for expanding the retrocarotid window and analyzed computed tomography angiography (CTA) data from patients with PCoA aneurysms to define parameters for low-coursing ICAs. Using cadaveric specimens, standard pterional craniotomies were fashioned and extradural or intradural periclinoid surgical maneuvers-cutting of the meningo-orbital band, anterior clinoidectomy, and cutting of the distal dural ring (DDR)-were performed, and their relative advantages for expanding the retrocarotid window were assessed. Additionally, preoperative CTA data from 24 patients with PCoA aneurysms used to calculate the angles of the ICA relative to the skull base. Periclinoid maneuvers, especially the anterior clinoidectomy, provided additional exposure of the retrocarotid space. Cutting of the DDR allowed for partial mobilization of the ICA and widened the retrocarotid surgical window, enhancing maneuverability. The anterior clinoidectomy with cutting of the DDR allowed for enhanced exposure of the medial, middle, and posterolateral aspects of the retrocarotid space. Cutting the anterior petroclinoid fold and mobilizing cranial nerve III provided wide exposure of the lateral aspect of retrocarotid space. When clipping PCoA aneurysms in the presence of normal-coursing ICAs (approximately ≥30° ICA angle), a standard pterional craniotomy with anterior clinoidectomy and cutting of the DDR allows for substantial expansion of the retrocarotid window.

Expansive carotid artery remodeling: possible marker of vulnerable plaque.

Accumulated findings in the pathophysiology of atherosclerosis have demonstrated that not only luminal narrowing but also plaque characteristics influence the risk of future ischemic events. The morphology of the carotid artery (CA) changes in response to atherosclerotic development by expansive remodeling (ER), the clinical significance of which remains unclear. This study aimed to define associations between ER and local risk factors, including CA geometry and traditional systemic risk factors for ischemic events, to determine whether ER could serve as a clinical marker of carotid vulnerable plaque. The authors retrospectively analyzed 66 patients with CA stenosis who were scheduled to undergo carotid endarterectomy or CA stenting. They calculated ER ratios in the internal CA (ICA) from long-axis MR images and as the maximal distance between the lumen and the outer borders of the plaque perpendicular to the axis of the ICA/the maximal luminal diameter of the distal ICA at a region unaffected by atherosclerosis. Relative overall signal intensity (roSI) was calculated to assess intraplaque hemorrhage and defined as the signal intensity of plaque on an axial T1-weighted image with maximal stenosis relative to that of the adjacent sternocleidomastoid muscle. The authors evaluated CA geometry by calculating the angles between the common CA (CCA) and ICA, and between the CCA and external CA (ECA) using digital subtraction angiography. The ER ratios, age, sex, percentage of stenosis, roSI, hypertension, hyperlipidemia, low-density lipoprotein, statin medication, diabetes, smoking habit, and ischemic heart disease were compared between 33 symptomatic and 33 asymptomatic patients. The authors also compared symptomatic status, age, sex, percentage of stenosis, ICA angle, ECA angle, roSI, and other traditional atherosclerotic risk factors between groups with extensive and slight ER. The ER ratio was significantly greater in symptomatic than in asymptomatic patients (1.91 ± 0.46 vs 1.68 ± 0.40, p < 0.05). The ICA angle was significantly larger in the group with extensive ER than in those with slight ER (33.9° ± 20.2° vs 21.7° ± 13.8°, p < 0.01). The roSI, ECA angle, percentage stenosis, or any other traditional vascular risk factors were not associated with ER. Carotid ER might be an independent indicator of carotid vulnerable plaque, which should be validated in a longitudinal study of patients with carotid atherosclerosis, including those with nonstenotic to moderate stenosis.

Association between extracranial internal carotid artery tortuosity and thromboembolic complications during coil embolization of anterior circulation ruptured aneurysms.

The most frequent neurological complication during coil embolization of a ruptured cerebral aneurysm is a thromboembolic event. The association between the tortuosity of the internal carotid artery (ICA) and thromboembolic events (TEEs) during coil embolization of ruptured cerebral aneurysms remains unclear. The present study aimed to investigate the association between extracranial ICA tortuosity and thromboembolic complications during coil embolization of anterior circulation ruptured aneurysms. A cohort of 57 patients with 57 anterior circulation ruptured aneurysms who underwent endovascular embolization at a single institution was retrospectively investigated. Patients were divided into two groups, those who experienced TEEs and those who did not that were compared and analyzed based on patient baseline characteristics, procedural factors, and anatomical factors including those of aneurysms and extracranial ICA tortuosity. The anatomical factors of the aneurysms included maximum dome size, neck width, dome-to-neck ratio, and dome-to-neck aspect ratio. Extracranial ICA angles in the proximal and distal curvature were evaluated as ICA tortuosity. Three of the 57 patients were excluded because of unavailability of data regarding ICA tortuosity; 54 patients were finally evaluated. TEEs occurred in six patients with five anterior cerebral and one internal carotid aneurysms. The extracranial distal ICA angle was significantly larger in patients with TEEs than in those without. Procedural factors and anatomical factors of the aneurysms were not associated with TEEs. Extracranial ICA tortuosity was significantly associated with an increased incidence of thromboembolic events during endovascular coiling of anterior circulation ruptured aneurysms.

Clinical significance of the internal carotid artery angle in ischemic stroke

The carotid artery plays a major role in stroke aetiology and is a good indicator of atherosclerosis. However, the clinical significance of internal carotid artery (ICA) anatomy remains unclear in patients with ischaemic stroke. This study examined the relationship between ICA angle and risk of ischaemic stroke. ICA angles of patients with acute ischaemic stroke were retrospectively compared with those of control patients between March 2014 and July 2014. Controls consisted of those with headaches but without ischaemic stroke. In both groups, ICA angles were measured using Maximum Intensity Projection images from computed tomography angiography, and the relationship between ICA angle and risk of ischaemic stroke was analysed. Of 128 screened patients with acute ischaemic stroke, 27 were enrolled, and 29 with headache were enrolled as controls. No differences were found in baseline characteristics between the two groups, but intracranial stenosis was more frequent in patients with stroke than in controls. Bilateral ICA angles were significantly larger in patients with stroke than in controls. Multiple logistic regression models showed that the right ICA angle was associated with risk of ischaemic stroke. Measuring the ICA angle may help assess the risk of ischaemic stroke.

Longitudinal study of carotid artery bifurcation geometry using magnetic resonance angiography.

Carotid artery geometry has been suggested as a risk factor for atherosclerotic carotid disease. Although normal aging and disease development can both lead to geometric changes in the arteries, the exact nature of this phenomenon remains elusive. The aim of our study was to investigate carotid artery geometric changes in a longitudinal study. We conducted a retrospective study of 114 subjects who underwent carotid contrast-enhanced magnetic resonance angiography at our clinic at baseline (2005 to 2007) and after 10 years. The right (Rev#2-1) carotid arteries were segmented using semi-automated methods to obtain various measurements of carotid artery geometry. For each patient, these parameters were assessed at both time points, including bifurcation angle, internal carotid artery angle, vessel diameter, and circumference. The median age for the total patient population (n = 114) at baseline was 59.06 ± 10.40 years. Mean time interval between baseline magnetic resonance angiography and magnetic resonance angiography after 10 years of these patients was 129.18 ± 7.77 months. For the whole group, there was a significant increase in the bifurcation angle (p < 0.05) over a 10-year period. A significant increase was also noted in the diameter and circumference of the common carotid artery (p < 0.05). However, the other vessel diameters and circumferences (bulb carotid, internal carotid) as well as the internal carotid angle did not significantly change (p ≥ 0.05). The diameter and circumference of the common carotid artery and bifurcation angle significantly increased over a decade of life.

Longitudinal study of carotid artery bifurcation geometry using magnetic resonance angiography.

Geometry of carotid artery has been known as a risk factor for atherosclerotic carotid disease. Though aging and disease progression can both attribute to geometric changes in the arteries, the exact nature of this phenomenon remains elusive. The aim of our study was to investigate carotid artery geometric changes in a longitudinal study. We conducted a retrospective study of 114 subjects who underwent carotid contrast-enhanced magnetic resonance angiography at our clinic at baseline (2005 to 2007) and after 10 years. The right carotid arteries were segmented using semi-automated methods to obtain various measurements of carotid artery geometry. For each patient, these parameters were assessed at both time points, including bifurcation angle, internal carotid artery angle, vessel diameter, and circumference. The median age for the total patient population ( n = 114) at baseline was 59.06 ± 10.40 years. Mean time interval between baseline magnetic resonance angiography and magnetic resonance angiography after 10 years of these patients was 129.18 ± 7.77 months. For the whole group, there was a significant increase in the bifurcation angle ( p < 0.05) over a 10-year period. A significant increase was also noted in the diameter and circumference of the common carotid artery ( p < 0.05). However, the other vessel diameters and circumferences (bulb carotid, internal carotid) as well as the internal carotid angle did not significantly change ( p ≥ 0.05). The diameter and circumference of the common carotid artery and bifurcation angle significantly increased over a decade of life.

Abstract TP242: Internal Carotid Artery Angle and the Risk of Floating Mural Thrombosis in Acute Cerebral Infarction Patients

Background and Purpose: Floating mural thrombosis in an internal carotid artery (ICA) is a rare and uncommon pathology with a high risk of embolism. Carotid anatomy and geometry may play a role in the pathogenesis of internal carotid artery stenosis. However, their effects to the formation of thrombus are unknown. Therefore, we sought to find whether the ICA angle affected the formation of thrombus or not. Method: We retrospectively analyzed 603 consecutive patients with a diagnosis of acute cerebral stroke from April 2015 to June 2017. We conducted brain MRI/MRA scans and carotid ultrasonography to assess the atherosclerotic change and the prevalence of mural thrombosis. We found four patients (0.6%) with a mobile mural thrombus in the ICA without a significant stenosis. As a control group, we also chose 24 patients who had atherothrombotic infarctions with 50% or less ICA stenosis. We measured the ICA angle which is the angle of deviation of the ICA from a vertical line drawn through the center of the common carotid artery. We investigated the degree of ICA angle as well as traditional vascular risk factors and coagulation factors. Results: The mural thrombosis group was younger than the control group (60.5±14.7 vs. 76.5±8.7 years, p&lt;0.01). The ICA angle was significantly wider in patients with floating mural thrombosis (56.0°:IQR 33.3 to 69.6° vs. 24.5°:IQR 19.9 to 34.6°, p=0.009). There were no significant differences in coagulation factors, vascular risk factors, and comorbidities between the mural thrombosis group and the control group. Conclusion: Our study implies that wide ICA angle is an important factor for the formation of the floating mural thrombosis as well as developing carotid artery atherosclerosis.

Relationship between carotid artery atherosclerosis and bulb geometry.

The carotid bifurcation is a common site of atherosclerotic plaque. Plaque development is thought to occur preferentially at geometrically predisposed areas such as arterial branch points. The aim of this study was to investigate the geometric and anatomical variables that contribute to the development of carotid plaque using three-dimensional (3D) ultrasound. Sixty-seven consecutive outpatients referred for elective coronary angiography underwent 3D carotid ultrasound scans for the purpose of carotid plaque quantification. Geometric quantification of the left and right carotid bulbs were performed retrospectively on this study population. Geometric values such as angle, area and length of the carotid bulb and the bifurcation were determined using QLAB software (Philips Healthcare). Plaque volume within the carotid bulb and artery branches was quantified using the stacked contour method. Pearson's correlation and linear regression analysis were used to determine the relationship between anatomical variables and plaque volume. The mean age for the total patient population was 65.9 ± 11.5years. Carotid bulb inflow area (BIA) (r = 0.28, p = 0.001), bulb volume (BV) (r = 0.21, p = 0.01) and bifurcation angle (BifA) (r = 0.18, p = 0.04) showed a positive linear relationship with plaque volume. In contrast, internal carotid artery angle (ICAA) (r = - 0.18, p = 0.04) and bulb flare (r = - 0.20, p = 0.02) displayed a negative linear relationship with plaque volume. When adjusting for age and sex, only the BIA remained significant (β = 0.18, p = 0.04). Geometric variables were identified as potential risk factors associated with plaque volume in the carotid bulb. Further analysis of the evolution of the BIA as well as the relationship to other geometric variables could create a stronger predictive model of atherosclerosis as well as assist in preoperative planning.

Widening and Rotation of Carotid Artery with Age: Geometric Approach

The anatomy and geometry of the carotid artery may play an important role in the pathogenesis of internal carotid artery (ICA) stenosis, but the exact nature of this role remains elusive. To clarify this issue, we sought to investigate age-related changes in the anatomy and geometry of the carotid artery in a Korean population. We conducted a retrospective study of 300 subjects who underwent carotid contrast-enhanced magnetic resonance angiography at our clinic between 2014 and 2016. The subjects were divided into 7 groups according to age. The carotid arteries were segmented using semiautomated methods to obtain various measurements of carotid anatomy and geometry, as suggested by Thomas etal. The various age groups were compared for different parameters, including ICA angle, bifurcation angle, and vessel volume and diameter. Analysis of variance showed that with an increase in age, there were significant increases in vessel volume and diameter of the common carotid artery and ICA as well as the carotid bifurcation (P = .000). Significant age-related increase was also noted in the ICA angle and bifurcation angle (P = .000). The anatomical position of the ICA in subjects aged over 60 years was significantly higher than that in subjects below 40 years (12.5% versus .03%, P < .0001). Age-related increases were noted in vessel volume and diameter of the carotid artery and ICA as well as the bifurcation angle. The widening and rotation of the carotid artery increased with age.