Diameter Of Intracranial Arteries Research Articles

Correlation between Circle of Willis configuration and intracranial arterial dolichoectasia, and genetic contributions

ObjectivesIntracranial arterial dolichoectasia (IADE) is characterized by the dilation, elongation, and tortuosity of intracranial arteries. We aimed to investigate the association between variations of the Circle of Willis (COW) and IADE in the general population, as well as estimate the genetic correlation between COW variations and IADE. MethodsA total of 981 individuals from a population-based cohort were included. Brain magnetic resonance angiography was performed to assess COW variants and measure the diameters of intracranial arteries. IADE was defined as a total intracranial volume-adjusted diameter ≥ 2 standard deviations. Logistic regression models were used to analyze the association between COW variations and IADE. The heritability and genetic correlation were estimated using genome-wide complex trait analysis (GCTA) based on single nucleotide polymorphism (SNP) array data. ResultsThe prevalence of IADE was 6.2 %. Hypoplastic/absent A1 segments were associated with an increase in contralateral ICA diameter (β ± SE, 0.279 ± 0.049; p = 0.001) and a decrease in ipsilateral ICA diameter (β ± SE, -0.300 ± 0.050; p = 0.001). Fetal-type posterior cerebral artery (FTP) was associated with a larger ICA diameter (β ± SE, 0.326 ± 0.048; p = 0.001) and a smaller BA diameter (β ± SE, -0.662 ± 0.043; p = 0.001). FTP revealed a positive genetic correlation with ICA dilation (rG = 0.259 ± 0.175; p = 0.0009) and a negative genetic correlation with BA dilation (rG = -0.192 ± 0.153, p = 0.015). ConclusionsThere was an association between COW variations and larger intracranial arterial diameters in the general population. Genetic factors may play a role in the development of intracranial arterial dilation and the formation of COW variants.

Higher cerebral blood flow on four-dimensional flow magnetic resonance imaging in young women.

We investigated the reduction in regional brain volume and cerebral blood flow (CBF) with aging and explored potential sex differences in healthy brains. Three-dimensional (3D) T1-weighted magnetic resonance imaging (MRI), time-of-flight magnetic resonance angiography, and four-dimensional (4D) flow MRI were performed on 129 healthy volunteers aged 22-92 years. The brains of healthy volunteers were segmented into 21 subregions using 3D T1-weighted MRI and CBFs in 16 major intracranial arteries were measured using 4D flow MRI. The cortical gray matter volume decreased linearly with aging, whereas the cerebral white matter volume increased until the 40s and then decreased, and the subcortical gray matter volume changed little with aging. The cortical gray matter volume was significantly associated with the total CBF of the major intracranial arteries distal to the circle of Willis; however, the cerebral white matter and subcortical gray matter volumes were not. Generally, women have higher total CBF than men, particularly in their 40s and younger, despite the smaller intracranial volume and smaller diameters of intracranial arteries than men. This may contribute to the higher incidence of subarachnoid hemorrhage due to cerebral aneurysms and migraine in women.

Arterial Stiffness is Associated with Intracranial Arterial Stenosis other than Dolichoectasia in the General Population.

Aims: The relationship between central arterial stiffness and aging-related intracranial arteriopathy is not well investigated in the general population. In a population-based study, we investigated arterial stiffness in relation to intracranial atherosclerotic stenosis and intracranial arterial dolichoectasia.Methods: This study was a cross-sectional analysis on 1,123 subjects (aged 56.0 ± 9.3 years, 37.9% men) of the population-based Shunyi study in China. Arterial stiffness was assessed by measuring brachial-ankle pulse wave velocity (baPWV). Intracranial atherosclerotic stenosis and intracranial arterial dolichoectasia were evaluated via brain magnetic resonance angiography. Multivariate regression models were constructed to investigate the association between baPWV and intracranial large artery diseases.Results: Increased baPWV was significantly associated with higher prevalence of intracranial atherosclerotic stenosis (odds ratio for the highest quartile of baPWV compared with the lowest quartile, 3.66 [95% confidence interval, 1.57–8.54]), after adjustment for cardiovascular risk factors in multivariate analysis. BaPWV was not associated with the presence of basilar artery dolichoectasia and dilation of basilar artery and internal carotid artery. When the diameters of intracranial arteries were regarded as continuous variables, increased baPWV was inversely related to the internal carotid artery diameter in fully adjusted models (β ± SE, −0.083 ± 0.042, p = 0.047).Conclusions: This population-based study demonstrates that arterial stiffness was more likely associated with intracranial stenotic arteriopathy other than intracranial dilative arteriopathy.

Matrix metalloproteinase‐3 and intracranial arterial dolichoectasia

Intracranial arterial dolichoectasia (IADE), also called dilatative arteriopathy of the brain, is defined as an increase in length and diameter of intracranial arteries. Abdominal aortic aneurysm and ectasia of coronary arteries have been reported in association with IADE. In both conditions, a dysfunction of matrix metalloproteinases (MMP)-2, -3, and -9 have been found. Our aim was to investigate these MMP pathways in stroke patients with IADE. Five hundred ten Caucasians patients with brain infarction were consecutively recruited at 12 centers. The diagnosis of IADE was made by consensus between 2 neurologists based on magnetic resonance imaging scans. Determination of MMP-2, -3, and -9 plasma levels was centralized in 1 laboratory. Because we found a threshold effect of MMP-3 plasma levels with the risk of IADE, determination of the MMP-3 5A/6A polymorphism was carried out. IADE was identified in 12% of stroke patients. There was no association of IADE with mean MMP-2, -3, and -9 plasma levels. After categorization of MMP plasma levels into tertiles, we found a higher risk of IADE with the lowest MMP-3 tertile (adjusted odds ratio [OR], 2.48; 95% confidence interval [CI], 1.17-5.23). In genotype analysis, there was a significant additive effect of the 5A allele on the risk of IADE, with an adjusted OR of 1.62 (95% CI, 1.03-2.55). In this cohort of stroke patients of Caucasian ancestry, IADE was associated with low MMP-3 plasma levels and with the 5A/6A polymorphism of the promoter region of MMP-3. These results suggest that MMP-3 may play a role in IADE.

The effect of surgery on the severity of vasospasm

Intracranial aneurysm surgery performed between 4 and 12 days after subarachnoid hemorrhage (SAH) has been associated with an increased risk of delayed cerebral ischemia and poor outcome compared to surgery performed before or after this time. To investigate whether this increased risk is due to aggravation of vasospasm, the angiograms obtained before and after surgery in 56 patients operated on at various times after aneurysmal SAH were studied. Vasospasm was quantitated by measuring the diameters of intracranial arteries and expressed as the ratio of the diameters of the intracranial arteries to the diameter of the extracranial internal carotid artery. Aggressive surgical clot removal was not performed at surgery. To correct for differences in prognostic factors for vasospasm between patients operated on at different times after SAH, multiple regression analysis was performed using the arterial diameter ratio during vasospasm as the dependent variable and the prognostic factors for vasospasm, including the time of surgery, as independent variables. Equations predicting the severity of vasospasm could be generated using the clinical grade on admission, patient age, and preoperative arterial diameter ratio. The time of surgery had no effect on vasospasm. Cerebral infarction due to vasospasm developed in five (15%) of 34 patients operated on within 3 days after SAH and in four (20%) of 20 operated on between 4 and 12 days after SAH (p = 0.66). A good outcome for these two groups was achieved in 88% and 85%, respectively (p = 1.00). These results suggest that the timing of surgery does not affect the development of vasospasm. Any increased risk of cerebral ischemia associated with surgery performed between 4 and 12 days after SAH is due to factors other than aggravation of vasospasm.

MRI of intracranial arteries in nitroglycerin induced cluster headache attacks.

Eight patients with episodic cluster headache, five in active episode, three out of episode, were investigated as to diameters of intracranial arteries before and after nitroglycerin (NG) administration. The diameter of all intracranial carotids were increased about 10 minutes after NG, although more in the patients in episode than in patients out of episode. The dilatation remained for the next 60 minutes in the patients who did not get a cluster headache attack. There was a normalization of the diameters of the internal carotid arteries compared to the initial values, at maximum pain in all patients who got a cluster headache attack. Similar changes were also found in the basilar arteries. The findings support the hypothesis of a constriction of intracranial arteries at maximum pain in cluster headache attacks to stop the pain.