Unilateral Internal Carotid Artery Stenosis Research Articles

Arterial transit artifacts and carotid Plaque-RADS may predict symptoms in patients with carotid stenosis

AimTo analyze the correlation of carotid stenosis severity, the Plaque Reporting and Data System (RADS) score, arterial transit artifacts (ATAs), and cerebral blood flow (CBF) with clinical cerebral ischemic symptoms in patients with carotid artery stenosis (CAS). Materials and methodsSixty-one patients with unilateral internal carotid artery stenosis or occlusion (≥50% stenosis) diagnosed by ultrasound, Computed Tomography(CT) angiography, or Magnetic Resonance(MR) angiography in Yichang City Central People's Hospital from January 2022 to February 2024 were retrospectively enrolled and divided into two groups according to the presence or absence of symptoms. Both groups underwent MR plaque imaging and arterial spin labeling (ASL)-based 3.0 T MRI to compare the differences in stenosis degree, Plaque-RADS score, ATA grade, and CBF between the two groups. Binary regression analysis was used to identify the parameters with statistically significant differences between the two groups and to evaluate their diagnostic efficacy using the area under the workup curve of the subjects. ResultsThe Plaque-RADS score, ATA grade, and CBF differences in the anterior cerebral artery(ACA)blood supply region were correlated with symptoms, and the areas under the ROC curves for the CBF differences in the ACA blood supply region, Plaque-RADS score, ATA grade and a joint model that combines all three to predict symptoms in CAS patients were 0.672, 0.796, 0.788 and 0.919, respectively. ConclusionsCBF, Plaque-RADS and ATAs were identified as independent risk factors for symptoms in patients with CAS and have a certain predictive value for symptoms, and the combined predictive value is greater, potentially providing a more effective imaging modality for clinical treatment and evaluation.

Macro- and microvascular contributions to cerebral structural alterations in patients with asymptomatic carotid artery stenosis.

Atherosclerosis can underly internal carotid artery stenosis (ICAS), a major risk factor for ischemic stroke, as well as small vessel disease (SVD). This study aimed to investigate hemodynamics and structural alterations associated with SVD in ICAS patients. 28 patients with unilateral asymptomatic ICAS and 30 age-matched controls underwent structural (T1-/T2-weighted and diffusion tensor imaging [DTI]) and hemodynamic (pseudo-continuous arterial spin labeling and dynamic susceptibility contrast) magnetic resonance imaging. SVD-related alterations were assessed using free water (FW), FW-corrected DTI, and peak-width of skeletonized mean diffusivity (PSMD). Furthermore, cortical thickness, cerebral blood flow (CBF), and capillary transit time heterogeneity (CTH) were analyzed. Ipsilateral to the stenosis, cortical thickness was significantly decreased in the posterior dorsal cingulate cortex (p = 0.024) and temporal pole (p = 0.028). ICAS patients exhibited elevated PSMD (p = 0.005), FW (p < 0.001), and contralateral alterations in FW-corrected DTI metrics. We found significantly lateralized CBF (p = 0.011) and a tendency for lateralized CTH (p = 0.067) in the white matter (WM) related to ICAS. Elevated PSMD and FW may indicate a link between SVD and WM changes. Contralateral alterations were seen in FW-corrected DTI, whereas hemodynamic and cortical changes were mainly ipsilateral, suggesting SVD might influence global brain changes concurrent with ICAS-related hemodynamic alterations.

Internal carotid artery stenosis: hemodynamics in the ipsilateral ACA affects CT angiography manifestations.

This study aimed to evaluate whether CT angiography (CTA) manifestations in anterior cerebral artery a1 segment (A1) were related to the hemodynamics in patients with internal carotid artery stenosis (ICAS). A total of 97 cases were selected. The degree of ICAS and symmetry of A1 were evaluated by CTA examination. Hemodynamic indexes were detected by transcranial Doppler (TCD). The differences in CTA presentations of A1 and hemodynamics between the vessels on the stenotic and contralateral sides were analyzed according to the different degrees of stenosis. The degree of ICAS according to the different manifestations of A1 and the hemodynamics of A1's adjacent vessels were also analyzed. In the case of unilateral ICAS, the difference in Vm of A1 between the stenotic and the contralateral side was the most significant relative to the stenosis degree. When unilateral ICAS was ≥70%, the presentation of A1 on the stenotic side was more slender or non-visualized compared to that on the contralateral side, while in cases with unilateral stenosis <70% or bilateral stenosis with a similar degree of stenosis, A1 were mainly symmetrical. When A1 on the side of ICAS was slender or non-visualized, the Vm of A1 was significantly slower than that on the contralateral side (P < 0.001). The CTA manifestations of A1 on the side of ICAS embodied the overall changes of the intracranial hemodynamics after ICAS. A combination of TCD and CTA examination of A1 can assist in judging the location and degree of ICAS.

Reduced-order modeling and analysis of dynamic cerebral autoregulation via diffusion maps

Objective. A data-driven technique for parsimonious modeling and analysis of dynamic cerebral autoregulation (DCA) is developed based on the concept of diffusion maps. Specifically, first, a state-space description of DCA dynamics is considered based on arterial blood pressure, cerebral blood flow velocity, and their time derivatives. Next, an eigenvalue analysis of the Markov matrix of a random walk on a graph over the dataset domain yields a low-dimensional representation of the intrinsic dynamics. Further dimension reduction is made possible by accounting only for the two most significant eigenvalues. The value of their ratio indicates whether the underlying system is governed by active or hypoactive dynamics, indicating healthy or impaired DCA function, respectively. We assessed the reliability of the technique by considering healthy individuals and patients with unilateral internal carotid artery (ICA) stenosis or occlusion. We computed the sensitivity of the technique to detect the presumed side-to-side difference in the DCA function of the second group (assuming hypoactive dynamics on the occluded or stenotic side), using McNemar’s chi square test. The results were compared with transfer function analysis (TFA). The performance of the two methods was also compared under the assumption of missing data. Main results. Both diffusion maps and TFA suggested a physiological side-to-side difference in the DCA of ICA stenosis or occlusion patients with a sensitivity of 81% and 71%, respectively. Further, both two methods suggested the difference between the occluded or stenotic side and any two sides of the healthy group. However, the diffusion maps captured additional difference between the unoccluded side and the healthy group, that TFA did not. Furthermore, compared to TFA, diffusion maps exhibited superior performance when subject to missing data. Significance. The eigenvalues ratio derived using the diffusion maps technique can be potentially used as a reliable and robust biomarker for assessing how active the intrinsic dynamics of the autoregulation is and for indicating healthy versus impaired DCA function.

Correlation between unilateral internal carotid artery stenosis and asymmetric distribution of enlarged perivascular spaces in patients with acute cerebral infarction

Objective: To explore the correlation between unilateral internal carotid artery (ICA) stenosis and asymmetrical distribution of enlarged perivascular spaces (EPVS) in patients with acute cerebral infarction. Methods: Acute cerebral infarction patients with unilateral ICA stenosis hospitalized in Changzhou Second People's Hospital from October 2020 to December 2021 were collected. Routine cranial MRI and CT angiography were completed for each patient. The 3D Slicer software was used to quantitatively analyze the volume of patient's EPVS. Patients were divided into moderate stenosis group and severe stenosis/occlusion group according to the degree of ICA stenosis. Baseline data were compared between the two groups. Patients were further divided into three groups: moderate stenosis, severe stenosis and occlusion groups, and the ipsilateral and contralateral EPVS volume of ICA stenosis patients was compared. The asymmetry index (AI) was calculated for EPVS in the basal ganglia region (BG-EPVS) and EPVS in the centrum semiovale (CSO-EPVS). Patients with AI≥0.2 were included in the EPVS asymmetry group, while the rest were in the EPVS symmetry group, and the degree of unilateral ICA stenosis was compared between the two groups. Multivariate logistic regression model was used to analyze the relationship between ICA severe stenosis/occlusion and the asymmetric distribution of BG-EPVS. Results: A total of 122 patients (96 males and 26 females) were enrolled, aged (70±10) years, with 81 cases in the unilateral ICA severe stenosis/occlusion group (46 cases of severe stenosis and 35 of occlusion) and 41 cases in the moderate stenosis group. Patients in the unilateral ICA severe stenosis/occlusion group had greater BG-EPVS volume [(4.08±0.76) mm3]and proportion of asymmetric distribution of BG-EPVS [75.3%(61/81)] than those of the moderate stenosis group [(3.12±0.85) mm3 and 39.0% (16/41)], with statistically significant differences (both P<0.001). The BG-EPVS volumes of the ipsilateral side of the stenosis in the severe stenosis group and the occlusion group [(3.34±0.86) mm3 and (3.93±0.60) mm3] were significantly greater than those of the contralateral side [(2.65±1.28) mm3 and (3.21±0.88) mm3], with statistically significant differences (both P<0.001). Correlation analysis indicated that the degree of unilateral ICA stenosis was positively correlated with the BG-EPVS volume on the stenosis side (r=0.62, P<0.001). Further comparison of the degree of unilateral ICA stenosis between the EPVS symmetric and asymmetric groups showed that the proportion of unilateral ICA severe stenosis/occlusion in the BG-EPVS asymmetry group was higher than that in the symmetric group [79.2%(61/77) vs 44.4%(20/45),P<0.001]. Multivariate logistic regression analysis showed that unilateral ICA severe stenosis/occlusion (OR=4.280, 95%CI: 1.743-10.508, P =0.002) and age (OR=1.055, 95%CI: 1.001-1.112, P=0.044) were risk factors for asymmetric distribution of BG-EPVS. Conclusions: The severe stenosis/occlusion of the unilateral ICA and age are the risk factors for the asymmetric distribution of the BG-EPVS in patients with acute cerebral infarction. The ipsilateral EPVS volume of unilateral ICA stenosis is larger than that of the contralateral side, and the degree of ICA stenosis is positively correlated with the severity of BG-EPVS.

Prediction of cerebral hyperperfusion following carotid endarterectomy using intravoxel incoherent motion magnetic resonance imaging

ObjectivesOne of the risk factors for cerebral hyperperfusion following carotid endarterectomy (CEA) is a chronic reduction in cerebral perfusion pressure due to internal carotid artery (ICA) stenosis, which is clinically detected as increased cerebral blood volume (CBV). The perfusion fraction (f) is one of the intra-voxel incoherent motion (IVIM) parameters obtained using magnetic resonance (MR) imaging that theoretically reflects CBV. The present study aimed to determine whether preoperative IVIM-f on MR imaging predicts development of cerebral hyperperfusion following CEA. Materials and MethodsSixty-eight patients with unilateral ICA stenosis (≥ 70%) underwent preoperative diffusion-weighted 3-T MR imaging, and IVIM-f maps were generated from these data. Quantitative brain perfusion single-photon emission computed tomography (SPECT) was performed before and immediately after CEA. Regions-of-interest (ROIs) were automatically placed in the bilateral middle cerebral artery territories in all images using a three-dimensional stereotactic ROI template, and affected-to-contralateral ratios in the ROIs were calculated on IVIM-f maps. ResultsNine patients (13%) exhibited postoperative hyperperfusion (cerebral blood flow increases of ≥ 100% compared with preoperative values in the ROIs on brain perfusion SPECT). Only high IVIM-f ratios were significantly associated with the occurrence of postoperative hyperperfusion (95% confidence interval, 253.8–6774.2; p = 0.0031) on logistic regression analysis. The sensitivity, specificity, and positive and negative predictive values of the IVIM-f ratio to predict the occurrence of postoperative hyperperfusion were 100%, 81%, 45%, and 100%, respectively. ConclusionsPreoperative IVIM-f on MR imaging can predict development of cerebral hyperperfusion following CEA.

Volumetric Flow Assessment in Extracranial Arteries in Patients with 70-99% Internal Carotid Artery Stenosis.

Background: Cerebral blood flow (CBF) can be related to the risk of occurrence of neurological symptoms. Well-developed collateral circulation is a good prognostic factor in patients with cerebrovascular disease. Understanding the mechanisms of collateral circulation may be important in the diagnosis, treatment, and monitoring in this group of patients. The aim of this study covered the assessment of CBF in patients with 70–99% Internal carotid artery (ICA) stenosis, focusing on the circulation pathways and flow volume in extracranial arteries. Materials and methods: 53 patients with 70–99% ICA stenosis (mean age 73.4 ± 7 years old; 17 female, mean age 73.9 ± 7.5 years old; 36 male, mean age 73.2 ± 6.8 years old) were included in the study. In all patients a Doppler ultrasound (DUS) examination, measuring blood flow volume in the internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA), was performed. The cerebral blood flow (CBF) was compared to the previously reported CBF values in the healthy population > 65 years old. Results: Among the study groups three subgroups with flow differences were identified: patients with elevated CBF (significant volumetric flow compensation—26/53, 49%), patients with CBF similar to (mild compensation—17/53, 32%), and patients with CBF lower than (no compensation—10/53, 19%) the healthy, equally aged population. The percentage of patients with significant volumetric flow compensation was the highest in age groups 65–69 years old (62.5%) and >80 years old (60%). In the oldest age group (>80 years old) no patients without flow compensation (0%) were observed. The level of compensation depends on the number of the arteries with compensatory increased flow. In patients with significant volumetric flow compensation, the compensatory increased flow was observed, on average, in 3.31 arteries, in the mild compensation group—in 2.18 arteries, and in the no compensation group only in 1 artery. ICA plays the most important role in the volumetric flow compensation—the increase in the flow volume, in comparison to the reference values, was between 116.7 mL/min and 251.9 mL/min (in the ECA 57.6 mL/min–110.4 mL/min; in the VA 73.9 mL/min–104.9 mL/min). The relative flow increase was highest in the VA: 215–246%, then in the ECA: 163–206%, and finally in the ICA: 148.6–192%. The increased flow was most commonly observed in the VA—57 arteries, in second place in the ECA—42 arteries, and ICA—31 arteries. In patients with unilateral ICA stenosis, the volumetric flow increase was stated more frequently in the ipsilateral ECAs then in the contralateral ones (23 vs. 14). In the VA the opposite tendency was observed (29 contralateral vs. 23 ipsilateral). The ability of volumetric flow compensation decreased significantly with increasing age. Conclusions: Understanding the mechanisms of collateral circulation and their assessment in Doppler ultrasonography may provide a novel and easily accessible tool of identifying and monitoring patients with cerebrovascular disease.

Arterial transit artifacts observed on arterial spin labeling perfusion imaging of carotid artery stenosis patients: What are counterparts on symptomatology, dynamic susceptibility contrast perfusion, and digital subtraction angiography?

PurposeTo investigate possible relationships between the presence and location of arterial transit artifacts (ATA) and clinical symptoms, digital subtraction angiography (DSA), and dynamic susceptibility contrast (DSC) perfusion imaging abnormalities in patients with carotid artery stenosis (CAS). MethodsForty-seven patients who underwent arterial spin labeling (ASL) and DSC perfusion imaging in the same period diagnosed with > 50% unilateral internal carotid artery (ICA) stenosis by DSA performed 24 h after perfusion imaging were included. The presence of ATA, localization and hypoperfusion were evaluated using ASL interpretation. Maps derived from DSC perfusion, symptomatology, stenosis rates, and collateralization findings observed in DSA were investigated. Probable relationships were evaluated. ResultsATA on ASL were detected in 68.1% (32/47); 40.6% (13/32) of ATAs were observed in the distal middle cerebral artery (MCA) trace, 50% (16/32) in the intracranial ICA and MCA traces, and 9.4% (3/32) in the intracranial ICA trace. When classifications based on the ATA presence and localization was made, qualitative and quantitative CBF, MTT, and TTP abnormalities, symptomatology, stenosis rates, and collateralization findings significantly differed between groups (p < 0.05). ConclusionThe presence and localization of ATA in patients with CAS may provide essential insights into cerebral hemodynamics and the CAS severity. ATAs observed only in the distal MCA trace may represent early-stage perfusion abnormalities and a moderate level of stenosis. ATA in the ICA trace may related to a more advanced level of perfusion abnormalities, critical stenosis rates, symptom or collateralization presence.

Bilateral Cerebral Infarctions Secondary to Unilateral ICA Stenosis

A 76-year-old diabetic man presented to us with complaints of sudden-onset right-sided weakness for the last 4 days. On evaluation, he was found to have right hemiparesis (Modified Medical Research Council grade 4-/5) along with left leg weakness (4+/5). Neuroimaging revealed acute infarcts in the right anterior cerebral artery (ACA) territory and left cerebral external watershed territory. Magnetic resonance (MR) angiogram of the brain showed a hypoplastic right A1-ACA with bilateral A2-ACA arising from the left A1-ACA (bi-hemispheric A1-ACA). MR angiogram of the neck revealed significant left internal carotid artery (ICA) origin stenosis. It was concluded that the origin of right A2-ACA from left ACA was the probable because of right ACA infarcts, along with left cerebral watershed infarcts (embolic phenomenon). This represents a very important variation, as in these cases, even a unilateral ICA stenosis can lead to bilateral ACA stroke and thus necessitates urgent revascularization.

Optical cohorence tomography angiography findings in carotid artery stenosis.

To investigate vascular density (VD) changes in the superficial (SCP) and deep capillary plexus (DCP), radial peripapillar capillary plexus (RPCP), Foveal avascular zone (FAZ) and thickness changes of peripapillary retinal nerve fiber layer (ppRNFL) and choroid (CT) using optical coherence tomography angiography (OCTA) ipsilateral eyes of patient with internal carotid artery stenosis (ICAS) and to compare the obtained values with kontralateral eyes of patients with İCAS and healthy individuals. This prospective cross-sectional case-control study was conducted in 43 patients with a diagnosis of unilateral ICAS and 47 age- and sex-matched healthy subjects. The patients were divided into three groups. Group 1 consisted of ipsilateral eyes of patients with ICAS, group 2 consisted of contralateral eyes of patients with CAS and group 3 comprised healthy individuals without ICAS, All participants underwent a comprehensive ophthalmologic examination including OCTA. FAZ, Superficial parafoveal and superficial superior VD were significantly lower in group 1 compared to group 2 (p = < 0.001, p = 0.018 and 0.021, respectively). Group 1 also had lower superficial superior (p = 0.038), superficial inferior (p = 0.034), deep superior (p = 0.034), and deep inferior (p = 0.012) VD compared to group 3. There was no significant difference between the groups in terms of ppRNFLT, whereas CT and RPC mean, superior, and inside-disc VD values were significantly lower in group 1 compared to both group 2 and 3 (p < 0.05). OCTA measurements may be useful in preventing irreversible ocular complications by detecting early structural changes in patients with ICAS before the development of symptomatic ocular ischemic syndrome.

Laterality of Posterior Cerebral Artery and White Matter Hyperintensities in Patients with Severe Internal Carotid Artery Stenosis.

Collateral status of the circle of Willis was associated with white matter hyperintensities (WMHs) in patients with internal carotid artery (ICA) stenosis, but few have investigated the effect of leptomeningeal anastomoses. The aim of this study was to observe the association between WMHs and the laterality of the posterior cerebral artery (PCA) that presents leptomeningeal anastomoses in patients with severe ICA stenosis. WMHs and ipsilateral PCA laterality were evaluated in patients with unilateral ICA stenosis ≥70% (including occlusion) and contralateral ICA stenosis <50% or no stenosis. Ipsilateral PCA laterality was compared between two groups of no/mild and severe score of global, deep and periventricular WMHs, respectively. We included 115 patients with unilateral ICA stenosis ≥70%. There were 60 patients with no/mild and 55 with severe global WMHs. The patients with severe global WMHs were older (OR = 1.849, 95% CI: 1.058-3.229, P = 0.031) and had higher incidence of negative PCA laterality (OR = 3.301, 95% CI: 1.140-9.558, P = 0.028). The patients with severe deep WMHs were also older (OR = 2.031, 95% CI: 1.130-3.651, P = 0.018) and had higher incidence of negative PCA laterality (OR = 4.250, 95% CI: 1.501-12.032, P = 0.006). There was no significant difference between the patients with no/mild and severe periventricular WMHs in the incidence of negative PCA laterality. The incidence of negative PCA laterality was higher in patients with severe global and deep WMHs, but not higher in patients with severe periventricular WMHs. The leptomeningeal anastomoses may affect the deep WMHs in patients with severe ICA stenosis.

Intrinsic functional brain connectivity is resilient to chronic hypoperfusion caused by unilateral carotid artery stenosis

IntroductionChronic cerebral hypoperfusion caused by asymptomatic high-grade stenosis of the internal carotid artery (ICA) has been associated with impaired cognitive function. Only few studies exist on underlying changes of functional connectivity (FC). Methods20 patients with unilateral high-grade ICA stenosis without MRI lesions and 25 aged-match controls underwent resting-state functional MRI (rsfMRI) and neuropsychological assessment. Patients were examined within ten days before and 6–10 weeks after surgical or interventional revascularization of carotid stenosis. We examined mean resting-state FC ipsi- and contralateral to stenosis and network topology using graph-theoretical measures. ResultsAt baseline, intrahemispheric FC was similar for patients and healthy controls. After revascularization mean FC increased moderately without an effect on network topology. Patients performed worse in TMT B and Stroop test, while performance in global screening tests for dementia (Mini Mental Status Examination, DemTect) were comparable. Test results did not improve after revascularization. ConclusionIn our study population, we find no effect of chronic hypoperfusion on FC and global cognitive function, although we observe minor impairments in processing speed and mental flexibility. The subtle increase of FC after revascularization could indicate excessive upregulation after restoration of perfusion. However, it might as well be a coincidental finding due to the limited sample size.

Combination of High-Density Lipoprotein Cholesterol and Lipoprotein(a) as a Predictor of Collateral Circulation in Patients With Severe Unilateral Internal Carotid Artery Stenosis or Occlusion.

Background and PurposeCollateral circulation is considered an important factor affecting the risk of stroke, but the factors that affect collateral circulation remain unclear. This study was performed to identify the factors associated with collateral circulation, especially blood lipids.MethodsThe study involved patients who had undergone digital subtraction angiography and were confirmed as having severe unilateral stenosis or occlusion of the internal carotid artery (ICA). We classified the collateral circulation status of each patient as good (Grade 3 or 4) or poor (Grade 0, 1, or 2) according to the grading system of the American Society of Interventional and Therapeutic Neuroradiology/American Society of Interventional Radiology. We collected data on patients’ characteristics and identified the factors that affect collateral circulation.ResultsThis study included 212 patients. The multivariate logistic regression analysis showed that the high-density lipoprotein cholesterol (HDL-C) concentration and a complete anterior half of the circle of Willis were independent protective factors for good collateral circulation, whereas elevated lipoprotein(a) [Lp(a)] and serum creatinine concentrations were independent risk factors for good collateral circulation. The area under the receiver operating characteristics curve (AUC) was 0.68 (95% confidence interval [CI], 0.61–0.76) for HDL-C and 0.69 (95% CI, 0.62–0.76) for Lp(a). A binary logistic regression model analysis of the joint factor of HDL-C and Lp(a) yielded an AUC of 0.77 (95% CI, 0.71–0.84).ConclusionsIn patients with severe unilateral ICA stenosis or occlusion, the combination of HDL-C and Lp(a) is a useful predictor of collateral circulation.

Can intracranial time-of-flight-MR angiography predict extracranial carotid artery stenosis?

ObjectivesExtracranial stenosis of the internal carotid artery (ICA) is an important cause of ischemic stroke and transient ischemic attack (TIA). It can be diagnosed using contrast-enhanced CT or MR angiography (MRA) as well as Doppler ultrasound. In this study, we assessed the diagnostic value of intracranial time-of-flight (TOF) MRA to predict extracranial ICA stenosis (ICAS).MethodsWe retrospectively analyzed consecutive patients with acute ischemic stroke or TIA and middle- (50–69%) or high-grade (70–99%) unilateral extracranial ICAS according to NASCET criteria assessed by ultrasound between January 2016 and August 2018. The control group consisted of patients without extracranial ICAS. Intraluminal signal intensities (SI) of the intracranial ICA on the side of the extracranial stenosis were compared to the contralesional side on TOF-MRA source images. SI ratios (SIR) of contralesional:lesional side were compared between groups.ResultsIn total, 151 patients were included in the main analysis. Contralesional:lesional SIR in the intracranial C4-segment was significantly higher in patients with ipsilateral extracranial ICA stenosis (n = 51, median 74 years, 57% male) compared to the control group (n = 100, median 68 years, 48% male). Mean SIR was 1.463 vs. 1.035 (p < 0.001) for right-sided stenosis and 1.362 vs. 1.000 (p < 0.001) for left-sided stenosis. Receiver-operating characteristic curve demonstrated a cut-off value of 1.086 for right-sided [sensitivity/specificity 75%/81%; area under the curve (AUC) 0.81] and 1.104 for left-sided stenosis (sensitivity/specificity 70%/84%; AUC 0.80) in C4 as a good predictor for high-grade extracranial ICAS.ConclusionsSIR on TOF-MRA can be a marker of extracranial ICAS.

The risk factors of old silent brain infarctions in carotid artery stenosis.

This study aims to investigate the risk factors of old ipsilateral silent brain infarctions (iSBIs) in patients with internal carotid artery (ICA) stenosis. Consecutive patients with unilateral ICA stenosis ≥ 50% or occlusion were retrospectively enrolled. Old iSBIs were assessed on magnetic resonance imaging. Baseline characteristics and imaging features were compared between patients with and without iSBIs. Multivariable regression analysis was conducted to identify independent risk factors of iSBIs. We enrolled 274 patients with unilateral ICA stenosis ≥ 50% or occlusion. One hundred thirty-three patients had iSBIs to stenosed ICA (48.54%). One hundred thirty-seven patients had recent brain infarction on either side (50.0%). The patients with iSBIs had a lower level of high-density lipoprotein [OR 0.60, 95% CI (0.36-0.96), P = 0.045], higher prevalence of irregular/ulcer plaque [OR 10.71, 95% CI (4.60-24.95), P < 0.0001], and incompleteness of circle of Willis [OR 0.27, 95% CI (0.16-0.45), P < 0.0001] in all enrolled patients. In the patients without recent infarction on either side, lower level of high-density lipoprotein [OR 0.42, 95% CI (0.27-0.88), P = 0.031], higher prevalence of irregular/ulcer plaque [OR 12.73, 95% CI (4.13-39.22), P < 0.0001] and incompleteness of circle of Willis [OR 0.24, 95% CI (0.11-0.50), P = 0.004] were independently associated with iSBIs. The results were similar in ICA stenosis patients with recent brain infarction on either side. In patients with carotid stenosis, incompleteness of circle of Willis, irregular/ulcer plaque, and lower level of high-density lipoprotein were independently associated with old iSBIs.

Usefulness of 2D-Perfusion Analysis for the Assessment of Unilateral Cervical Internal Carotid Artery Stenosis.

We investigated the usefulness of 2D-perfusion analysis for the evaluation of cerebral blood flow in unilateral cervical internal carotid artery stenosis. We conducted a 2D-perfusion analysis during cerebral angiography and 123I-iodoamphetamine (IMP) single photon emission computed tomography (SPECT) for unilateral cervical internal carotid artery stenosis without contralateral stenosis. The relationship between the ratio of the lesion side to the normal side in the parameters obtained by 2D-perfusion and the value calculated by stereotactic extraction estimation (SEE) analysis of SPECT was statistically examined. The ratios of the lesion side to the normal side regarding the peak arrival time (AT; time to peak [TTP]) of the contrast agent and the mean filling time (mean transit time [MTT]) of the contrast agent in 2D-perfusion significantly correlated with the area of Stage II and increase ratio (I.R) ≤30% in the SEE analysis (p = 0.002, 0.003). 2D-perfusion analysis can be used to estimate the extent of impaired cerebrovascular reserve (CVR) area in unilateral internal carotid artery stenosis.

Investigation of macular and optic nerve head structural changes using spectral domain optical coherence tomography in internal carotid artery stenosis

To demonstrate differences in optic nerve head (ONH), retinal nerve fiber layer (RNFL), and macular thickness in patients with internal carotid artery (ICA) stenosis using spectral domain optical coherence tomography (SD-OCT). A case-controlled study was conducted in 31 patients with a diagnosis of unilateral ICA stenosis (the percentage of stenosis was between 65 and 85%), and 53 age- and sex-matched healthy subjects (control group) from March 2016 to April 2018. The ONH parameters, RNFL, and macular thicknesses in the nine macular quadrants according to the Early Treatment Diabetic Retinopathy Study (ETDRS) were measured using SD-OCT. The average macular thickness and outer macular quadrants measurements were lower in the ICA stenosis group (P < 0.05). The thickness of the fovea and inner macular quadrants was similar in healthy and patient eyes. Similarly, the ONH and RNFL profiles based on SD-OCT parameters were similar between the groups. There was a negative weak correlation between mean macular and RNFL thicknesses and the duration and percentage of ICA stenosis. The average macular thickness and measurements of outer macular quadrants in the ICA stenosis group were lower than in the control group. Macular changes may occur before symptomatic ocular ischemic syndrome (OIS). SD-OCT macular measurements may be beneficial in the early detection of OIS due to ICA stenosis.

Diagnosis and clinical course of ocular ischemic syndrome with retinal vascular abnormalities due to unilateral ocular artery and internal carotid artery stenosis in a child with neurofibromatosis type 1: a case report

BackgroundNeurofibromatosis type 1 (NF1) is a hereditary disease that causes neurofibromas generally, but it has been reported to sometimes be associated with various forms of blood vessel stenosis, occlusion and vascular abnormalities of unknown mechanism. However, a symptomatic case with simultaneous ophthalmic artery stenosis and internal carotid artery stenosis is an extremely rare pathogenesis in a child with NF1. In this report, we performed the diagnosis and observation using various imaging modalities for this rare pediatric case.Case presentationA 6-year-old girl diagnosed with NF1 presented with gradual visual loss in the right eye. Best corrected visual acuity (BCVA) was 20/40 OD and the intraocular pressure (IOP) was normal in both eyes. Retinal vascular abnormalities with tortuous vessels and optic disc pallor were observed in the right fundus. Widefield fluorescein angiography revealed multiple sites of neovascularization and a large non-perfusion area in the peripheral retina. Optical coherence tomography angiography showed retinal vascular abnormalities in the right eye and revealed differences in inner retinal thickness and blood flow signal between the left and right eyes. Laser speckle flowgraphy showed that chorioretinal blood flow was significantly decreased in the right eye. Cerebral angiography revealed the right ophthalmic artery was significantly narrowed throughout. In addition, Magnetic resonance angiography revealed that the right internal carotid artery was significantly narrowed in the ophthalmic segment. We diagnosed ophthalmic artery and internal carotid artery stenosis with retinal vascular abnormalities and ocular ischemic syndrome in NF1. Because IOP increased to 35 mmHg, due to neovascular glaucoma in addition to mild vitreous hemorrhage occurred, panretinal photocoagulation was performed after intravitreal bevacizumab injection. After treatments, IOP normalized, but BCVA decreased to 20/100 OD. Arterial spin labeling showed normal cerebral blood flow. The patient is currently being carefully monitored.ConclusionsWe have described the diagnosis and treatment of ocular ischemic syndrome due to multiple arteries stenosis in a child with NF 1. Utilization of various imaging modalities was helpful in diagnosing the complicated pathogenesis. However, since direct intervention by neurosurgery is not possible in this case, it is expected that treatment will be extremely difficult in the future.

Silent brain infarcts and white matter lesions in patients with asymptomatic carotid stenosis.

The association of carotid atherosclerosis with silent brain infarcts (SBIs) and white matter lesions (WMLs) currently remains unknown. This study aims to compare SBIs, deep white matter lesions (DWMLs), and periventricular white matter lesions (PWMLs) in ipsilateral and contralateral hemispheres to internal carotid artery (ICA) stenosis, and investigate their association with stenosis grade in patients with asymptomatic ≥ 50% unilateral extracranial ICA stenosis. Patients without previous history of stroke and/or transient ischemic attack who had ≥ 50% stenosis in unilateral ICA on carotid color Doppler ultrasound were enrolled in the study. Patient demographics, vascular risk factors and ICA stenosis grades; number, location, and size of SBIs, DWMLs, and PWMLs in ICA territory were evaluated in both hemispheres using magnetic resonance imaging of the brain. Of the 69 patients, 53 had 50-69% (76.8%) and 16 had ≥ 70% (23.2%) unilateral ICA stenosis. There was no statistically significant difference in SBIs between ipsilateral and contralateral hemispheres to ≥ 50% ICA stenosis. Comparison of ICA stenoses as 50-69% and ≥ 70% revealed a greater number of patients with SBI in ipsilateral hemisphere to ≥ 70% stenosis compared to contralateral (p = 0.025). The number of SBIs was also higher in ipsilateral hemisphere to ≥ 70% stenosis compared to contralateral (p = 0.022). While DWMLs and PWMLs did not differ between hemispheres, frequency of Fazekas grade1 DWMLs was lower in ipsilateral hemisphere to either 50-69% or ≥ 70% ICA stenosis compared to contralateral (p = 0.035 and p = 0.025, respectively). Results of the present study indicate that stenosis grade may be relevant in the association between asymptomatic carotid stenosis and SBIs, and ≥ 70% stenosis may pose a risk of SBI development.

A Breath-Holding Index Applied to the Internal Carotid Artery Siphon in Transcranial Doppler Studies.

The breath-holding index (BHI) is a useful method to assess cerebrovascular reactivity. It is calculated based on the mean flow velocities of the middle cerebral artery (MCA) using transcranial Doppler (BHIMCA ). Therefore, it is not feasible in patients with poor temporal windows. This study tested the feasibility of a BHI using the internal carotid artery (ICA) siphon flow velocity (BHIICA ). Twenty-four patients (aged 38-79 years) with unilateral or bilateral stenosis of the cervical ICAs were prospectively recruited. The 48 examined bilateral ICAs were divided into three groups according to the stenosis degree: <50%, 50-99%, and occlusion. We investigated the reproducibility of both BHI methods (BHIMCA and BHIICA ), the correlation between the two BHI methods, and the tendency for the BHIs to decrease with increasing degree of cervical ICA stenosis. For the BHIMCA , we found a good reproducibility (intraclass correlation coefficient, rI > .9) and a significantly decreased BHI with increasing stenosis of the ICA (P = .001). For the BHIICA , good reproducibility was demonstrated (rI > or ≒ .9), but there was no significant decrease in the BHI related to the increasing degree of ICA stenosis (P = .952). Furthermore, the correlation between the two BHI methods was not robust (kappa coefficient, right .259; left .619). Our study suggests that the BHIICA is not a feasible alternative method to the BHIMCA.