Objective: We investigated whether circle of Willis (COW) morphology on 3D time-of-flight (TOF) MR angiography differs between young normal subjects, older normal subjects, and patients with carotid atherosclerotic plaques. Methods: One hundred seventy-seven subjects were grouped according to age into a young group (20 – 40 years; n = 91) and an older group (> 60 years; n = 86). Subjects underwent brain MR examination as part of a health check-up. Fifty-three patients with carotid atherosclerotic plaque were also included for evaluation in this study. COW morphology on 3D TOF MR angiography was analyzed in terms of completeness or incompleteness of the anterior and posterior components of the circle and completeness of the circle. Results: An incomplete pattern of anterior circulation was significantly more common in carotid atherosclerotic plaque patients (20.7%) than normal older subjects (5.5%) (p < 0.01). A complete posterior circulation pattern was more frequent in normal young subjects (46.5%) than in normal older subjects (16.5%) or the patient group (18.9%) (p < 0.01). Of patients with carotid artery stenosis, 18.9% had a bilateral incomplete connection and were significantly more likely to have an incomplete pattern than normal young (2.3%) or normal older subjects (2.2%) (p < 0.001). Conclusion: Young, healthy subjects were significantly more likely to have a complete pattern of posterior circulation than older subjects. Patients with carotid atherosclerotic plaques were significantly more likely to have incomplete anterior circulation and an incomplete circle than young, normal subjects.
Circle of Willis

No abstract available.
Aneurysm* ; Angiography* ; Circle of Willis*

Blood Pressure ; Cerebrovascular Circulation ; Circle of Willis ; Humans

PURPOSE: To determine differences in angiographic variations of the circle of Willis between atherosclerosis and normal groups. MATERIALS AND METHODS: In 289 patients we reviewed complete cerebral angiograms obtained using biplane digital subtraction angiography. Atherosclerosis was diagnosed in 189 patients, while 100 were normal. Patients were divided into four subgroups according to the relative size of each segment and the presence of cross-filling of opposite-sided vessels. When the circle was completely present, we determined whether or not it was balanced, and statistically compared variation patterns between the two groups. RESULTS: In the atherosclerosis group, the anterior half of the circle was complete in 74% of cases(139/189), and the posterior half in 38% (72/189). In the normal group, the anterior half was complete in 90% of cases, and the posterior half in 63%. An incomplete circle was more common in the atherosclerosis group than among normal subjects (26% vs 10%, p<.05; 62% vs 37%, p<.001). In the atherosclerosis group with incomplete circle, agenesis was found in the anterior communicating artery in 19% of cases (36/189), the A1 segment in 7% (14/189), the posterior communicating artery in 58% (109/189), and the P1 segment in 7% (14/189). In the normal group with incomplete circle, agenesis was seen in the anterior communicating artery in 9% of cases, in the A1 segment in 1%, in the posterior communicating artery in 36%, and in the P1 segment in 3%. Agenesis of the anterior communicating artery (19% vs 9%, p<.05), the A1 segment (7% vs 1%, p<.05), or the posterior communicating artery (58% vs 36%, p<.001) was more common in the atherosclerosis group than in the normal group. Unbalanced type with a size discrepancy between A1 segments was also more common in the atherosclerosis group (19% vs 8%, p<.05). There was no significant difference between the two groups regarding posterior communicating arteries equal to or larger than the P1 segment (42% vs 27%, p>.05) and agenesis of the P1 segment (7% vs 3%, p>.05). CONCLUSION: An incomplete and unbalanced circle of Willis was more common in the atherosclerosis group than in the normal group. Agenesis of the anterior communicating artery, the A1 segment, or the posterior communicating artery was common in the atherosclerosis group, as was size discrepancy between A1 segments.
Angiography, Digital Subtraction ; Arteries ; Atherosclerosis* ; Circle of Willis* ; Humans ; Intracranial Arteriosclerosis

Moyamoya disease is a progressive and occlusive disorder of the cerebral vasculature with particular involvements of the circle of Willis and the arteries that feed it. It occurs commonly in Japan and Korea, but less frequently in the Western countries. The etiology of moyamoya disease is still unclear, but frequent familial occurrence suggests that some genetic factors may be important in its etiology. Approximately 7-10% of moyamoya disease are familial. We experienced 2 siblings with moyamoya disease, and report the case with a review of previously published cases of moyamoya disease within a family.
Arteries ; Circle of Willis ; Humans ; Japan ; Korea ; Moyamoya Disease* ; Siblings*

Moyamoya disease is a cerebrovascular disease of unknown etiology which leads to spontaneous occlusion of circle of Willis. Cerebral ischemic or hemorrhagic episodes occur as moyamoya disease progresses. To establish an efficient collateral circulation for the ischemic brain of this disease many surgical the therapeutic methods have been proposed. We analyzed the surgical results of encephaloduroarteriomyosynangiosis(EDAMS) and compared with that of direct bypass surgery, superfical temporal artery to middle ce rebral artery(STA-MCA) anastomosis to determine the efficacy of new indirect revascularization procedure, EDAMS, in the treatment of moyamoya disease. Twenty three patients with moyamoya disease who underwent revascularization procedure were included in this study. EDAMS was performed on 18 sides in 16 patients and STA-MCA anastomosis was done on 12 sides in 7 patients. Two patients underwent encephaloduroarteriosynangiosis(EDAS). The surgical results of EDAMS were excellent to good in 14 patients and fair in 2 patients. No statistical significance of the outcome was observed in comparision of EDAMS and STA-MCA anastomosis(p-value=0.471). Regardless of surgical procedures, outcome of child-onset moyamoya disease was found to be superior to those of adult-onset moyamoya disease(p-delete=0.024). In conclusion, EDAMS is considered to be one of the effective indirect revascularization methods to prevent the ischemic attack and establish the revascularization for moyamoya disease.
Brain ; Circle of Willis ; Collateral Circulation ; Humans ; Moyamoya Disease ; Temporal Arteries

This article describes a straightforward method to measure the dimensions and identify morphological variations in the cerebral arterial circle using the general-purpose software program Osiris. This user-friendly and portable program displays, manipulates, and analyzes medical digital images, and it has the capability to determine morphometric properties of selected blood vessels (or other anatomical structures) in humans and animals. To ascertain morphometric variations in the cerebral arterial circle, 132 brains of recently deceased fetuses, infants, and adults were dissected. The dissection procedure was first digitized, and then the dimensions were measured with Osiris software. Measurements of each vessel's length and external diameters were used to identify and classify morphological variations in the cerebral arterial circle. The most commonly observed anatomical variations were uni- and bilateral hypoplasia of the posterior communicating artery. This study demonstrates that public domain software can be used to measure and classify cerebral arterial circle vessels. This method could be extended to examine other anatomical regions or to study other animals. Additionally, knowledge of variations within the circle could be applied clinically to enhance diagnostic and treatment specificity.
Adult ; Animals ; Arteries ; Blood Vessels ; Brain ; Circle of Willis ; Fetus ; Humans ; Infant ; Public Sector ; Sensitivity and Specificity

This study was designed to observe anoxia-induced responses and to clarify their possible mechanisms in porcine basilar and circle of Willis arteries. Anoxia produced a transient vasoconstriction, which then recovered to the basal tension of a 3-5 min. later, and the reoxygenation that follows produced the biphasic(relaxation-contraction) response in the intact endothelial rings under resting tension. The anoxia-induced contraction was potentiated by pretreatment with KC1 and PGF2alpha. Reoxygenation produced only sustained relaxation. Removal of the endothelium and pretreatment with nimodipine or indomethacine markedly attenuated the anoxia-induced contractions. Anoxia transiently and significantly increased cyclic GMP contents in the endothelium-intact preparations, but did not affect them in the endothelium-removed ones. The above results suggest that anoxia-induced contraction is endothelium-dependent and is resultant to the release of a Prostaglandin-like substance(s) .
Anoxia* ; Arteries ; Cerebral Arteries* ; Circle of Willis ; Cyclic GMP ; Dinoprost ; Endothelium ; Indomethacin ; Nimodipine ; Relaxation ; Vasoconstriction

We present the examination technique and normal values of flow velocity from intracranial basal cerebral arteries for a recently developed pulsed Doppler system operating at 2 MHz emitting frequency. Peak systolic, peak diastolic, and mean flow velocity values are analyzed from fast-Fourier transformed(FFT) Doppler spectra at selected depths for 50 presumed normal subjects ranging in age from 18 to 72 years. Interindividual variation is high for peak flow but moderate for mean flow velocity values, which hence are more likely to discriminate normal from abnormal. Flow velocity values within the posterior cerebral attery(PCA) and the basilar artery(BA) are significantly lower than in the anterior cerebral artery(ACA) and the middle cerebral artery(MCA), which is also unique in showing significantly decreasing values with increasing age. Calculated mean flow velocities are 61+/-14 cm/s in the middle cerebral artery(MCA) and 51+/-14 cm/s in the anterior cerebral artery(ACA), and 45+/-11 cm/s in the posterior cerebral artery(PCA) through the temporal window and 43+/-14 cm/s in the basilar artery through the suboccipital window and 15+/-5 cm/s in the ophthalmic artery and 47+/-13 cm/s in the internal carotid artery(lCA) through the transorbital window. A new scanning system is introduced, which we suggest will reduce interindividual variations and improve the accurate separation of nearby vessels, which are major causes of the comparatively large standard deviations at present.
Basilar Artery ; Cerebral Arteries* ; Circle of Willis ; Ophthalmic Artery ; Reference Values* ; Ultrasonography*

With 2mm-thick CT scanning during the rapid infusion of contrast material(TICT), cerebral aneurysms arising from the circle of Willis and adjacent vessels can be directly visualized. Twenty-five patients who had cerebral aneurysm confirmed by surgery were examined with TIGT and digital subtraction angiography. The authors examined TIGT prospectively to assess the detection rate of the cerebal aneurysms and to evaluate the clinical usefulness of TIGT. The detection rates of aneurysms by TIGT and digital subtraction angiography were 68% and 84%, respectively. TIGT is a rapid, safe and reliable method in the evaluation of patients with suspected cerebral aneurysm, permitting direct visualization of the aneurysm.
Aneurysm ; Angiography, Digital Subtraction ; Circle of Willis ; Humans ; Intracranial Aneurysm* ; Methods ; Prospective Studies ; Tomography, X-Ray Computed