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 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

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*

The authors studied and analyzed microscopically the structure, length and diameter of each part of Willis circle in 264 cerebral hemispheres of 182 autopsied patients in the Taegu area from 1984 to 1990. The mean length of each A1 was 14.1mm and diameter at distal A1 was 2.25mm. The most common anatomical anomaly of the ACA part was A1 that of hypoplasia which appeared in 7.5% of the cases. The origin of the Heuner a. was accounted for the highest incidence of AcoA(82.5%). The length of AcoA. Noted 3.5mm with the incidence of duplication and triplication in 38.6%. The inner diameter of ICA noted 3.9mm at the communicating segment in ICA, and the average length of C4 was 12.5m. Except 5 hemispheres of undetectable origin at ICA, all the anterior choroidal a. originated from ICA, and the double stump of which noted 15.5%. Fetal type PcoA. Showed 6.6% of all and average length of the a. was 13.5mm. The inner diameter of MCA was 3.1mm and the mean length of M1 noted 15.5mm. The length of each P1 noted 6.95mm and the inner diameter of basilar a. at 1cm below the bifurcation was 3.3mm. The mean circumference of willis circle including both side of A1, P1, PcoA. AcoA. And choroidal and communicating segment of ICA was 88.6mm. Incidental finding of unruptured aneurysm noted 5.3% and junctional dilatation of PcoA. Showed 11.4% of all the cases.
Aneurysm ; Cerebrum ; Choroid ; Circle of Willis* ; Daegu ; Dilatation ; Humans ; Incidence ; Incidental Findings

PURPOSE: To evaluate angiographic variations of the circle of Willis in a normal group, and to compare thepattern of these variations between normal and aneurysm groups. MATERIALS AND METHODS: We reviewed 220 cases inwhich subjects had undergone digital subtraction cerebral angiography which showed the circle of Willis in itsentirety. One hundred patients were diagnosed as normal, and 110 had an aneurysm. We reviewed the absence orpresence and relative size of each segment, and the configuration of the distal basilar artery. Where the circlewas complete, we evaluated whether or not the circle was balanced. And we compared the pattern of these variationsbetween the two groups. RESULTS: In the normal group, the most common pattern was a small anterior communicatingartery with symmetrically large A1 segments in the anterior circulation (27%) and symmetrically small posterior communicating arteries with large P1 segments in the posterior circulation (39%). The anterior half of the circlewas complete in 90% of cases, and the posterior half in 63%. In cases in which it was incomplete, there wasagenesis of the anterior communicating artery in 9% of cases, of the A1 segment in 1%, of the posterior communicating artery in 36%, and of the P1 segment in 3%. Unilateral absence of the posterior communicating arteryand P1 segment was noted in two cases. In the distal basilar artery, symmetric cranial fusion was most common,accounting for 77% of cases. In contrast, incomplete circles with agenesis of the A1 (1% vs 12%, p<.05) or P1segment (3% vs 10%, p<.05) were more common in the aneurysm group than among normal subjects. Unbalanced typeswith a size discrepancy between A1 segments (8% vs 18%, p<.05), or posterior communicating arteries equal to orlarger than the P1 segment (27% vs 46%, p<.05) were also more common. In the distal basilar artery, symmetriccranial fusion was most common, and accounted for 69% of cases. CONCLUSION: A complete and balanced circle wasmore common in the normal group. The most common pattern was a small anterior communicating artery withsymmetrically large A1 segments and symmetrically small posterior communicating arteries with large P1 segments.In contrast, incomplete or unbalanced circles were more common in the aneurysm group.
Aneurysm* ; Arteries ; Basilar Artery ; Cerebral Angiography ; Circle of Willis* ; Humans ; Intracranial Aneurysm

PURPOSE: To evaluate the usefulness of CT angiography (CTA) for the detection and assessment of intracranial aneurysms, compared with the findings of conventional angiography (CA) and surgery. MATERIALS AND METHODS: Among 243 patients who underwent CTA because of suspected intracranial a-neurysm, 116 who underwent surgery were studied. The patients were divided into two groups. Group 1 consisted of 77 patients (94 aneurysms) who underwent both preoperative CTA and CA, while group 2 comprised 39 patients (47 aneurysms) who underwent preoperative CTA only. The detection rate, size, shape and direction of the neck and its relationship to the adjacent vessel of the intracranial aneurysm seen during CTA were retrospectively compared with those seen during CA and surgery. Two radiologists worked in a blinded fashion without access to clinical information. RESULTS: In group 1, the detection rate of aneurysms seen during CTA was 89 % (84 of 94 cases), and for CA was 95 % (89 of 94 cases). Among ten undetected aneurysms, four cases were less than 3mm in size and six were out of the scanning area. In group 2, the detection rate of aneurysms seen during CTA was 94 %(44 of 47cases). Among three undetected aneurysms, one case was less than 3mm in size and two were out of the scanning area. For delineation of an aneurysm (the direction and shape of the neck, for example), CTA was equal or superior to CA in 75 of 82cases(91 % ). CONCLUSION: CTA is a useful technique for the evaluation of intracranial aneurysms in the circle of Willis, but cannot depict all vessels in the brain. CTA performed in conjunction with CA is useful for the detection of intracranial aneurysms.
Aneurysm ; Angiography* ; Brain ; Cerebral Angiography ; Circle of Willis ; Humans ; Intracranial Aneurysm ; Neck ; Retrospective Studies

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*