Unilateral Internal Carotid Artery Occlusion 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.

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.

Intracranial Flow Volume Estimation in Patients with Internal Carotid Artery Occlusion.

(1) Background: Carotid artery occlusion (CAO) in population studies has a reported prevalence of about 6 per 100,000 people; however, the data may be underestimated. CAO carries a significant risk of stroke. Up to 15% of large artery infractions may be secondary to the CAO, and in 27–38% of patients, ischaemic stroke is a first presentation of the disease. The presence of sufficient and well-developed collateral circulation has a protective influence, being a good prognostic factor in patients with carotid artery disease, both chronic and acute. Understanding the mechanisms and role of collateral circulation may be very important in the risk stratification of such patients. (2) Materials and Methods: This study included 46 patients (mean age: 70.5 ± 6 years old; 15 female, mean age 68.5 ± 3.8 years old and 31 male, mean age 71.5 ± 6.7 years old) with unilateral or bilateral ICA occlusion. 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. (3) Results: In comparison with CBF values in the healthy population, three subgroups with CBF changes were identified among patients with ICA occlusion: patients with significant volumetric flow compensation (CBF higher than average + standard deviation for healthy population of the same age), patients with flow similar to the healthy population (average ± standard deviation), and patients without compensation (CBF lower than the average-standard deviation for healthy population). The percentage of patients with significant volumetric flow compensation tend to rise with increasing age, while a simultaneous decline was observed in the group without compensation. The percentage of patients with flow similar to the healthy population remained relatively unchanged. ICA played the most important role in volumetric flow compensation in patients with CAO; however, the relative increase in flow in the ICA was smaller than that in the ECA and VA. Compensatory increased flow was observed in about 50% of all patent extracranial arteries and was more frequently observed in ipsilateral vessels than in contralateral ones, in both the ECA and the VA. In patients with CAO, there was no decrease in CBF, ICA, ECA, and VA flow volume with increasing age. (4) Conclusions: Volumetric flow compensation may play an important predictive role in patients with CAO.

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.

Three-Dimensional Iron Oxide Nanoparticle-Based Contrast-Enhanced Magnetic Resonance Imaging for Characterization of Cerebral Arteriogenesis in the Mouse Neocortex.

Purpose: Subsurface blood vessels in the cerebral cortex have been identified as a bottleneck in cerebral perfusion with the potential for collateral remodeling. However, valid techniques for non-invasive, longitudinal characterization of neocortical microvessels are still lacking. In this study, we validated contrast-enhanced magnetic resonance imaging (CE-MRI) for in vivo characterization of vascular changes in a model of spontaneous collateral outgrowth following chronic cerebral hypoperfusion.Methods: C57BL/6J mice were randomly assigned to unilateral internal carotid artery occlusion or sham surgery and after 21 days, CE-MRI based on T2*-weighted imaging was performed using ultra-small superparamagnetic iron oxide nanoparticles to obtain subtraction angiographies and steady-state cerebral blood volume (ss-CBV) maps. First pass dynamic susceptibility contrast MRI (DSC-MRI) was performed for internal validation of ss-CBV. Further validation at the histological level was provided by ex vivo serial two-photon tomography (STP).Results: Qualitatively, an increase in vessel density was observed on CE-MRI subtraction angiographies following occlusion; however, a quantitative vessel tracing analysis was prone to errors in our model. Measurements of ss-CBV reliably identified an increase in cortical vasculature, validated by DSC-MRI and STP.Conclusion: Iron oxide nanoparticle-based ss-CBV serves as a robust, non-invasive imaging surrogate marker for neocortical vessels, with the potential to reduce and refine preclinical models targeting the development and outgrowth of cerebral collateralization.

Patients Receiving Extracranial to Intracranial Bypass for Atherosclerotic Vessel Occlusion Today Differ Significantly From the COSS Population.

Despite the findings reported in the COSS (Carotid Occlusion Surgery Study), patients with atherosclerotic cerebrovascular disease continue to be referred for superficial temporal artery to middle cerebral artery bypass surgery. Here, we determined how today’s patients differ from the population reported in COSS. We retrospectively analyzed all patients that were referred to our Department for superficial temporal artery to middle cerebral artery bypass surgery of atherosclerotic cerebrovascular disease following the publication of COSS. Between 2012 and 2019, 179 patients were referred for 186 bypass surgeries. Ninety-one (51%) patients suffered atherosclerotic, unilateral internal carotid occlusion and 88 (49%) atherosclerotic multivessel disease. All patients had received intensive medical management. A single transitory ischemic attack or ischemic stroke within the last 120 days according to the inclusion criteria of COSS occurred in only 36 out of 179 (20%) patients, whereas 27 out of 179 (15%) suffered >1 transitory ischemic attack within 120 days, 109 out of 179 (61%) had recurrent minor ischemic stroke, and 7 out of 179 (4%) were hemodynamically unstable and required blood pressure maintenance. The distribution of symptoms did not differ between atherosclerotic unilateral internal carotid artery occlusion and atherosclerotic multivessel disease (P=0.376) but hemodynamic impairment was significantly greater in atherosclerotic multivessel disease (P<0.001 for atherosclerotic multivessel disease versus atherosclerotic unilateral internal carotid artery occlusion). The overall perioperative stroke rate was 4.3%. Patients referred for flow augmentation surgery today appear to suffer more severe symptoms and vessel occlusion patterns than patients reported in COSS. A new, carefully designed randomized controlled trial appears warranted, considering the still poor prognosis of severe atherosclerotic cerebrovascular disease.

Leptomeningeal collateral activation indicates severely impaired cerebrovascular reserve capacity in patients with symptomatic unilateral carotid artery occlusion

For patients with symptomatic unilateral internal carotid artery (ICA) occlusion, impaired cerebrovascular reactivity (CVR) indicates increased stroke risk. Here, the role of collateral activation remains a matter of debate, whereas angio-anatomical collateral abundancy does not necessarily imply sufficient compensatory flow provided. We aimed to further elucidate the role of collateral activation in the presence of impaired CVR. From a prospective database, 62 patients with symptomatic unilateral ICA occlusion underwent blood oxygenation-level dependent (BOLD) fMRI CVR imaging and a transcranial Doppler (TCD) investigation for primary and secondary collateral activation. Descriptive statistic and multivariate analysis were used to evaluate the relationship between BOLD-CVR values and collateral activation. Patients with activated secondary collaterals exhibited more impaired BOLD-CVR values of the ipsilateral hemisphere (p = 0.02). Specifically, activation of leptomeningeal collaterals showed severely impaired ipsilateral hemisphere BOLD-CVR values when compared to activation of ophthalmic collaterals (0.05 ± 0.09 vs. 0.12 ± 0.04, p = 0.005). Moreover, the prediction analysis showed leptomeningeal collateral activation as a strong independent predictor for ipsilateral hemispheric BOLD-CVR. In our study, ipsilateral leptomeningeal collateral activation is the sole collateral pathway associated with severely impaired BOLD-CVR in patients with symptomatic unilateral ICA occlusion.

Mapping Cerebrovascular Reactivity Impairment in Patients With Symptomatic Unilateral Carotid Artery Disease.

BackgroundComprehensive hemodynamic impairment mapping using blood oxygenation‐level dependent (BOLD) cerebrovascular reactivity (CVR) can be used to identify hemodynamically relevant symptomatic unilateral carotid artery disease.Methods and ResultsThis prospective cohort study was conducted between February 2015 and July 2020 at the Clinical Neuroscience Center of the University Hospital Zurich, Zurich, Switzerland. One hundred two patients with newly diagnosed symptomatic unilateral internal carotid artery (ICA) occlusion or with 70% to 99% ICA stenosis were included. An age‐matched healthy cohort of 12 subjects underwent an identical BOLD functional magnetic resonance imaging examination. Using BOLD functional magnetic resonance imaging with a standardized CO2 stimulus, CVR impairment was evaluated. Moreover, embolic versus hemodynamic ischemic patterns were evaluated on diffusion‐weighted imaging. Sixty‐seven patients had unilateral ICA occlusion and 35 patients unilateral 70% to 99% ICA stenosis. Patients with ICA occlusion exhibited lower whole‐brain and ipsilateral hemisphere mean BOLD‐CVR values as compared with healthy subjects (0.12±0.08 versus 0.19±0.04, P=0.004 and 0.09±0.09 versus 0.18±0.04, P<0.001) and ICA stenosis cohort (0.12±0.08 versus 0.16±0.05, P=0.01 and 0.09±0.09 versus 0.15±0.05, P=0.01); however, only 40 (58%) patients of the cohort showed significant BOLD‐CVR impairment. Conversely, there was no difference in mean BOLD‐CVR values between healthy patients and patients with ICA stenosis, although 5 (14%) patients with ICA stenosis showed a significant BOLD‐CVR impairment. No significant BOLD‐CVR difference was discernible between patients with hemodynamic ischemic infarcts versus those with embolic infarct distribution (0.11±0.08 versus 0.13±0.06, P=0.12).ConclusionsComprehensive BOLD‐CVR mapping allows for identification of hemodynamically relevant symptomatic unilateral carotid artery stenosis or occlusion.

Increased Ipsilateral Posterior Cerebral Artery P2-Segment Flow Velocity Predicts Hemodynamic Impairment.

Increased Transcranial Doppler flow velocity in the ipsilateral P2-segment of the posterior cerebral artery (PCA-P2: cm/second) is associated with recurrent cerebrovascular events in patients with unilateral internal carotid artery occlusion. However, its predictive value and correlation with hemodynamic impairment in an overall stroke patient cohort remains to be determined. Transcranial doppler PCA-P2 flow velocity was measured in 88 patients with symptomatic unilateral steno-occlusive disease who also underwent blood oxygenation-level dependent cerebrovascular reactivity imaging (blood oxygenation-level dependent [BOLD]-cerebrovascular reactivity [CVR]). A multivariate linear regression was used to evaluate the independent correlation between the ipsilateral PCA-P2 flow velocity measurements and hemispheric BOLD-CVR. Follow-up BOLD-CVR imaging data, available in 25 patients, were used to evaluate the temporal evolution of the BOLD-CVR and PCA-P2 flow velocity association using a mixed-effect model. Furthermore, a transcranial doppler cutoff for hemodynamic failure stage 2 was determined. The ipsilateral systolic PCA-P2 flow velocity strongly correlated with hemispheric BOLD-CVR (R=0.79; R2=0.61), which remained unchanged when evaluating the follow-up data. Using a PCA-P2 systolic flow velocity cutoff value of 85 cm/second, patients with BOLD-CVR based hemodynamic failure stage 2 were diagnosed with an area under the curve of 95. In patients with symptomatic unilateral steno-occlusive disease, increased ipsilateral transcranial doppler PCA-P2 systolic flow velocity independently correlates with BOLD-CVR based hemodynamic failure. A cutoff value of 85 cm/second appears to indicate hemodynamic failure stage 2, but this finding needs to be validated in an independent patient cohort.

Does cerebral hemodynamic compromise contribute to cerebral cortical microinfarcts: A proof of concept study in patients with internal carotid artery occlusion

AbstractBackgroundCerebral cortical microinfarcts (CMI) are small ischemic lesions that are associated with cognitive impairment and are often detected in patients with dementia, also in patients with a clinical diagnosis of Alzheimer’s disease (AD). CMI probably have multiple etiologies. Cerebral hypoperfusion has also been proposed as a causal factor. We studied CMI in patients with internal carotid artery (ICA) occlusion, as a model for cerebral hemodynamic compromise, addressing CMI presence and spatial distribution, also in relation to the condition of the remaining arterial supply.MethodsWe included 95 patients with a complete ICA occlusion (age 66.2±8.3, 22% female) and a reference group of 125 participants (age 65.5±7.4, 47% female) from the Heart‐Brain Study. Participants underwent an extensive evaluation including clinical and neuropsychological assessment, and 3T brain MR, on which CMI were rated according to standardized criteria.ResultsCMI were more common in patients with an ICA occlusion (54%, median 2, range 1‐33) than in the reference group (6%, median 0; range 1‐7) (OR 14.3; 95% CI 6.2‐33.1; p&lt;.001). Among patients with a unilateral ICA occlusion, CMI were more common ipsilateral to the occlusion than in the contralateral hemisphere (median 2 and 0 respectively; p&lt;.001). In patients with CMI the number of (other) occluded or stenosed cervical arteries was higher (p=.038), and cerebral blood flow tended to be lower (B ‐6.2 ml/min/100ml; 95% CI ‐12.4‐0.02; p=.05) than in patients without CMI.ConclusionCMI are very common in patients with an ICA occlusion, preferably in the hemisphere of the occluded ICA and CMI burden was related to the severity of cervical arterial compromise. Supporting the etiological role of hemodynamics in the occurrence of CMI. Given the common occurrence of CMI in patients with AD and known effects of AD on cerebral perfusion, further studies on the interplay between AD pathologies, cerebral perfusion and CMIs in relation to clinical outcomes, in particular cognitive decline, are warranted.

A case of primary hypophysitis with cavernous sinus infiltration causing an unilateral internal carotid artery occlusion

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Magnetic resonance markers of bilateral neuronal metabolic dysfunction in patients with unilateral internal carotid artery occlusion.

To evaluate cerebral hemodynamic, metabolic and anatomic changes occurring in patients with unilateral occlusion of the internal carotid artery (ICA). Twenty-two patients with unilateral occlusion of ICA and twenty age and sex matched healthy subjects were included in the study. Single voxel proton magnetic resonance spectroscopy (1H-MRS) of the centrum semiovale, semi-automated hippocampal volumetry in T1-weighted scans and transcranial Doppler examination (TCD) with calculation of Breath Holding Index (BHI) were performed in both groups. Metabolic, anatomic, and hemodynamic features were compared between the two groups. The N-acetylaspartate (NAA)/choline (Cho) ratio was significantly lower in both hemispheres of enrolled patients compared to controls (p = 0.005 for the side with occlusion, p = 0.04 for the side without occlusion). The hippocampus volume was significantly reduced bilaterally in patients compared to healthy subjects (p = 0.049). A statistically significant difference in BHI values was observed between the side with occlusion and without occlusion (p = 0.037) of the patients, as well as between BHI values of the side with occlusion and healthy volunteers (p = 0.014). Patients with unilateral ICA occlusion have reduced NAA/Cho ratio in the white matter of both hemispheres and have bilateral atrophy of hippocampus. The alteration of hemodynamics alone cannot explain these changes.

Pattern of Activated Pathways and Quality of Collateral Status in Patients with Symptomatic Internal Carotid Artery Occlusion

Background: Internal carotid artery occlusion (ICAO) is an important risk factor for stroke. Cerebral hemodynamics in patients with ICAO depends on the individual capacity to activate sufficient collateral pathways. Therefore, the assessment of intracranial collaterals is essential for the acute and long-term management of these patients and accurate estimation of further stroke risk. Methods: Acute stroke patients with unilateral ICAO were prospectively enrolled. We assessed the following collaterals by transcranial color-coded sonography (TCCS): the anterior and posterior communicating artery (ACoA, PCoA), the ophthalmic artery (OA), and leptomeningeal collaterals of the posterior cerebral artery (LMC). We subdivided the flow pattern of the Doppler spectrum in the middle cerebral artery (MCA) into 3 categories: (1) good, (2) moderate, and (3) bad according to the hemodynamic effects on the ipsilateral MCA flow. Finally, we compared the individual TCCS results with the stroke pattern detected on CT or MRI scan. Results: One hundred thirteen patients (age 66 ± 12 years; ­female 24) were included. The collateral status was good, moderate, and bad in 59 (52%), 37 (33%), and 17 (15%) patients, respectively. The ACoA collateral was most frequently activated (81%), followed by the OA (63%), the PCoA (53%), and the LMC (22%). The quality of the collateral status was determined by the type (p = 0.0003) but not by the number (p = 0.19) of activated collateral pathways. Good collateral function was highly associated with primary collaterals (ACoA > PCoA). Best parameter for a good collateral status was an antegrade flow in the OA, indicating a high blood supply via the communicating arteries. Conclusions: TCCS allows the assessment of intracranial collaterals and their hemodynamic capacity. Prevalence of collateral sufficiency in ICAO seems to be higher than previously reported. ACoA cross flow is essential for the optimal hemodynamic compensation of ICAO. Antegrade OA flow indicates good collateral status.

Added assessment of middle cerebral artery and atrial fibrillation to FLAIR vascular hyperintensity-DWI mismatch would improve the outcome prediction of acute infarction in patients with acute internal carotid artery occlusion

Whether fluid-attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH)-DWI mismatch could predict the outcome or not remains in debate. The aim of this study was to identify if FVH combined with the other markers improved favorable outcome prediction of acute infarctions in patients with unilateral acute internal carotid artery (ICA) occlusion. Consecutive 68 adult acute middle cerebral artery (MCA) territory infarction patients caused by acute ICA occlusion, including favorable (n = 38, mRS ≤ 2) and unfavorable (n = 30, mRS > 2) groups, were enrolled in this retrospective analysis. The diagnostic efficiency of favorable clinical outcome of FVH-DWI mismatch was compared with those of DWI lesions volumetry and the combined marker of FVH-DWI mismatch and other factors. There were more prominent FVH-DWI mismatch (≥ 3 sections) (84%), less atrial fibrillation (AFib) (13%), and more tandem MCA normal or mild stenosis (63%) in favorable outcome group than those (30%, 40%, and 27%, respectively) in unfavorable group. Univariate and multivariate analyses showed that the prominent FVH-DWI mismatch was the positive predictive factor for favorable outcome (OR = 2.643 and 3.200). Prominent FVH-DWI mismatch, in combination with tandem MCA normal or mild stenosis, and absence of Afib, had better performance (AUC = 0.875) than that of initial DWI lesion volumetry (AUC = 0.854) and any other single factor (AUC = 0.634~0.820) in predicting favorable outcome. Prominent FVH-DWI mismatch was associated with favorable outcome in acute infarctions in unilateral ICA occlusion patients. Its predictive performance would be improved when combined with the assessment of tandem lesions of MCA and AFib.

Hemodynamic characteristics associated with cerebral aneurysm formation in patients with carotid occlusion.

The pathogenesis of cerebral aneurysms in patients with internal carotid artery (ICA) occlusion is hypothesized to be hemodynamic. For the first time, the authors quantify the hemodynamic characteristics associated with aneurysm formation in patients with ICA occlusion. Records of patients with unilateral ICA stenosis or occlusion ≥ 90% who underwent hemodynamic assessment before treatment using quantitative MR angiography were retrospectively reviewed. The patients were classified into 2 groups based on the presence or absence of aneurysms. The hemodynamic parameters of flow volume rate, flow velocity, and wall shear stress (WSS) were measured in each vessel supplying collateral flow-bilateral A1 segments and bilateral posterior communicating arteries-and then compared between the groups. A total of 36 patients were included (8 with and 28 without aneurysms). The mean flow (72.3 vs 48.9 ml/min, p = 0.10), flow velocity (21.1 vs 12.7 cm/sec, p = 0.006), and WSS (22.0 vs 12.3 dynes/cm2, p = 0.003) were higher in the A1 segment contralateral to the side of the patent ICA in patients with versus without aneurysms. All de novo or growing aneurysms in our cohort were located on the anterior communicating artery (ACoA) or P1 segment. Flow velocity and WSS are significantly higher across the ACoA in patients who harbor an aneurysm, and de novo or growing aneurysms are often located on collateral vessels. Thus, robust primary collaterals after ICA occlusion may be a contributing factor in cerebral aneurysm formation.

The influence of collateral circulation recruitment on various cognitive functions after severe unilateral stenosis or unilateral occlusion of the internal carotid artery

Objective To investigate the influence of collateral circulation recruitment on cognitive functions in patients with severe unilateral stenosis or unilateral occlusion of the internal carotid artery by using TCD. Methods A total of 176 patients with severe unilateral stenosis or unilateral occlusion of the internal carotid artery were enrolled and were divided into a single vessel collateral group(n=80, 45.5%), a multiple vessel collateral group(n=74, 42.1%)and a no collateral group(n=22, 12.5%). In order to study the influence of single vessel collateral circulation on cognitive functions, the single vessel collateral group was further divided into an anterior communicating subgroup(AcoA), a posterior communicating subgroup(PcoA), an ocular artery subgroup(OA), and a normal control subgroup.All patients and 34 normal controls(NC)received MoCA, and scores for the overall assessment and individual domains were analyzed. Results Compared with the control group(26.3±1.1, 4.7±0.5, 2.0±0.0, 3.6±1.0), the multiple vessel collateral group, the single vessel collateral group and the no collateral group had lower overall scores(24.2±1.7, 21.9±2.3, 19.0±2.4), lower executive/visuospatial function(3.9±0.7, 3.2±0.8, 2.4±0.6), lower abstraction(1.7±0.5, 1.6±0.5, 1.3±0.5), and lower delayed recall(2.9±0.8, 1.9±0.8, 1.6±0.5)(F=80.52, 63.21, 12, 48.99, all P<0.05); both collateral groups had lower scores in subtraction and attention(4.6±0.6 vs. 5.2±0.7, 4.3±0.7 vs. 5.2±0.7); the no collateral group had lower scores in orientation(4.7±0.7 vs. 5.7±0.5)(P<0.05). Compared with the multiple vessel collateral group, both the single vessel collateral group and the no collateral group had lower overall scores(21.9±2.3 vs. 24.2±1.7, 19.0±2.4 vs. 24.2±1.7), executive/visuospatial function(3.2±0.8 vs. 3.9±0.7, 2.4±0.6 vs. 3.9±0.7), subtraction and attention(4.6±0.6 vs. 5.1±0.5, 4.3±0.7 vs. 5.1±0.5)(all P<0.05); the no collateral group had lower scores in abstraction(1.3±0.5 vs. 1.7±0.5), delayed recall(1.6±0.5 vs. 2.9±0.8)and orientation(4.7±0.7 vs. 5.7±0.5)(all P<0.05). Compared with the single vessel collateral group, the no collateral group had lower overall scores(19.0±2.4 vs. 21.9±2.3), executive/visuospatial function(2.4±0.6 vs. 3.2±0.8)and orientation(4.7±0.7 vs. 5.7±0.6)(all P<0.05). In single vessel collateral patients, the AcoA subgroup had higher MoCA scores than the PcoA subgroup(22.9±1.7 vs. 21.2±2.7)(P<0.05), and the AcoA subgroup had higher scores in delayed recall than the OA subgroup(2.2±0.8 vs. 1.7±0.6)(P<0.05). Conclusions Severe unilateral stenosis or unilateral occlusion in the internal carotid artery can result in cognitive impairment, especially in executive/visuospatial function, abstraction, delayed recall, subtraction and attention.However, collateral circulation can protect cognitive function in patients with unilateral internal carotid artery stenosis or occlusion and multiple vessel collateral circulation is more effective than single vessel collateral circulation, and AcoA is more effective than either PcoA or OA, but the difference between PcoA and OA is not significant. Key words: Transcranial Doppler; Internal carotid artery; Severe stenosis or occlusion; Collateral circulation; Cognitive function

GW28-e1102 Magnetic resonance markers of bilateral neuronal metabolic dysfunction in patients with unilateral internal carotid artery occlusion

To evaluate cerebral hemodynamic, metabolic and anatomic changes occurring in patients with unilateral occlusion of internal carotid artery. Twenty two patients with unilateral occlusion of ICA and twenty eight age and sex matched healthy subjects were included in the study. In both groups we

Observation of blood flow characteristics of collateral circulation of ipsilateral ophthalmic artery in patients with internal carotid artery occlusion

Objective To observe the characteristics of collateral circulation blood flow of ipsilateral ophthalmic artery in patients with internal carotid artery occlusion. Methods The imaging data of 20 patients with internal carotid artery occlusion were analyzed retrospectively. There were 11 males and 9 females, aged from 30 to 65 years, with an average age of (45±3) years. All the patients underwent digital subtraction angiography and transcranial Doppler examination, and 6 patients underwent simultaneous magnetic resonance angiography. The blood supply and collateral circulation of the ipsilateral ophthalmic artery were observed . Results All the patients had unilateral internal carotid artery occlusion. The blood supply of the ipsilateral internal carotid artery and ophthalmic artery comes from the collateral circulation between the middle meningeal artery branches of the external carotid artery and the ophthalmic artery in 18 patients (90.0%); it also comes from the anterior communicating artery of the contralateral internal carotid artery in 16 patients (80.0%); and the posterior communicating artery of the contralateral internal carotid artery in 12 patients (60.0%), respectively. Conclusion The blood flow of the ipsilateral ophthalmic artery mainly comes from the middle meningeal artery branch of the ipsilateral external carotid artery, also comes from the anterior and posterior communicating arteries of the contralateral internal carotid artery. Key words: Arterial occlusive diseases; Ophthalmic artery; Collateral circulation; Angiography, digital subtraction; Ultrasonography, Doppler, transcranial

Perfusion criteria of the EICMA efficacy in patients with symptomatic occlusion of the internal carotid artery

To investigate changes in cerebral perfusion in patients with unilateral internal carotid artery occlusion before and after surgical revascularization of the brain, depending on the clinical efficacy of surgical treatment. The study included 60 patients with unilateral ICA occlusions who underwent placement of an extra-intracranial microvascular anastomosis (EICMA). All patients underwent a CT perfusion study before and after cerebral revascularization. In addition, the degree of neurological deficit was evaluated before surgery and during follow-up (3 and 8-10 months) using the NIHSS score. All patients were divided into 3 groups, depending on the results of surgical treatment: objective improvement (43 patients), no changes (14 patients), and worsening of clinical symptoms (3 patients). In each group, the absolute and relative perfusion parameters (MTT, CBV, and CBF) were analyzed to identify the perfusion criteria for the EICMA efficacy. A significant relationship between the clinical efficacy of EICMA and a baseline perfusion deficit and its change after anastomosis placement was found. Placement of EICMA is effective treatment for patients with symptomatic ICA occlusions and an increase in the blood transit time in the hemisphere ipsilateral to occlusion by more than 40% compared to that in the opposite side provided that perfusion is recovered in more than one area of the MCA territory (in accordance with the ASPECTS scale).

Oxygen extraction fraction measurement using quantitative susceptibility mapping: Comparison with positron emission tomography

The purposes of this study are to establish oxygen extraction fraction (OEF) measurements using quantitative susceptibility mapping (QSM) of magnetic resonance imaging (MRI), and to compare QSM–OEF data with the gold standard 15O positron emission tomography (PET). Twenty-six patients with chronic unilateral internal carotid artery or middle cerebral artery stenosis or occlusion, and 15 normal subjects were included. MRI scans were conducted using a 3.0 Tesla scanner with a three-dimensional spoiled gradient recalled sequence. QSM images were created using the morphology-enabled dipole inversion method, and OEF maps were generated from QSM images using extraction of venous susceptibility induced by deoxygenated hemoglobin. Significant correlation of relative OEF ratio to contra-lateral hemisphere between QSM–OEF and PET–OEF was observed (r = 0.62, p < 0.001). The local (intra-section) correlation was also significant (r = 0.52, p < 0.001) in patients with increased PET–OEF. The sensitivity and specificity of OEF increase in QSM was 0.63 (5/8) and 0.89 (16/18), respectively, in comparison with PET. In conclusion, good correlation was achieved between QSM–OEF and PET–OEF in the identification of elevated OEF in affected hemispheres of patients with unilateral chronic steno-occlusive disease.