Angiographic Analysis of the Circle of Willis: Comparison between Normal and Aneurysm groups

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.

Angiographic Analysis of the Circle of Willis: Comparison between Atherosclerosis and Normal Groups

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) 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.

Angiographic Analysis of Cerebral Aneurysm

PURPOSE: To analyze the angiographic findings of cerebral aneurysms and to compare them with previousdomestic and foreign reports. MATERIAL AND METHODS: Three hundred and seventeen patients underwent DSA(digitalsubtraction angiography) and the results were retrospectively, reviewed. Among 278 patients, 356 cerebralaneurysms were detected. Patient's age and sex ratio were analysed, as well as the location, size and multiplicityof the aneurysms. RESULT: The most prevalent age group was 40 to 60 years (n=211, 76%), and the male to femaleratio was 1:1.5. Aneurysms were located in the anterior (n=324, 91%) or posterior circulation(n=32, 9%). In theformer, the most common locations were the anterior communicating artery (n=98, 28%), middle cerebral artery (MCA)bifurcation(n=65, 18%) and the posterior communicating artery (n=32, 9%), while in the pasterior circulation, themost common location was the basilar tip(n=11, 3%). One hundred and eighty-eight cerebral aneurysms(53%) were 3-6mm in size, and 75(21%) were 6-10mm. The size of nine aneurysms (3%) was more than 25mm. Multiple aneurysms(n=149)occurred in 65 patients(23%) ; the most common age group was 40 to 60 (74%) and the male to female ratio was 1:4.The most common number of multiple aneurysms were two (77%) and the common locations were the posteriorcommunicating artery (21%), MCA bifurcation (18%) and anterior communicating artery (13%). CONCLUSION: Weanalyzed a large series in a single center and therefore expect that our data will be helpful for the analysis ofaneurysms in the cerebral circulation and for comparison with domestic and foreign studies.

Analysis of Angiographic Findings in Cerebral Arteriovenous Malformation with Hemorrhage: Comparison between Intracerebral and Intraventricular Hemorrhage

PURPOSE: The purpose of this study was to analyze the angioarchitectures of cerebral arteriovenousmalformation(AVM) and to determine whether there was correlation between angioarchitectures and patterns ofintracranial hemorrhage(intracerebral, intraventricular, and both) in cerebral AVM. MATERIALS AND METHODS: Onehundred and twenty-eight patients who between November 1989 and December 1994 suffered supratentorial AVM withintracranial hemorrhage were studied retrospectively. Among 128 patients, intracerebral and intraventricularhemorrhage were seen in 68 (53%) and 24 patients (19%), respectively, while both types were seen in the remaining36 (28%). We analyzed the angioarchitectual characteristics of AVM. namely nidi, feeding arteries and drainingveins, in three hemorrhagic groups of patients with intracerebral hemorrhage, intraventricular hemorrhage andboth. The kappa2 test or Fisher's exact test was used for statistical analysis. RESULTS: A cortically located niduswas most common in patients with intracerebral hemorrhage, while a periventricular location was most common inthose with intraventricular hemorrhage (p<0.001). Location in the corpus callosum, choroid plexus, orintraventricular area was more frequent in the intraventricular than the intracerebral hemorrhagic group (p<0.05). Superficial venous drainage was most common in patients with intracerebral hemorrhage (p<0.001), and deep venousdrainage in those with intraventricular hemorrhage (p=0.001). CONCLUSION: The angioarchitectual characteristicsof cerebral arteriovenous malformation correlate significantly with patterns of intracranial hemorrhage, andawareness of the type of hemorrhage could help to manage patients and determine prognosis.

Analysis of Angiographic Findings in Arteriovenous Malformations (AVM) of Brain According to PresentingClinical Manifestations

PURPOSE: To evaluate the different angio-architectures of brain arteriovenour malformatigns (AVMs) accordingto the presence of non-hemorrhagic symptoms or intracerebral (ICH) and/or intraventricular hemorrhage(IVH). MATERIALS AND METHODS: The results of complete cerebral angiography obtained in 215 patients with AVM between1989 and 1994 were retrospectively reviewed. The M:F ratio was 136:78 and their mean age was 29 (ranged 4 - 66)years. On the based of clincal presentation, CT and/or MR images, they were divided into hemorrhagic andnon-hemorrhagic groups. Angiograms were analyzed by two radiologists for the size and location of nidus; thenumber of feeding arteries and the extent of aneurysm, stenosis, dural supply, and angiomatous change; the numberof draining veins and the extent of deep or superficial drainage, stenosis, ectasia, kinking, and stasis. Thestandard chi-square test was used for statistical analysis. RESULTS: Hemorrhage was noted in 140 patients(65%),and no hemorrhage in 75(35%). Hemorrhage was more common in AVM with deep-seated and callosal locations, a nidusof less than 2cm, single feeder and single venous drainage, and deep venous drainage only (p < 0.05 - 0.001).Non-hemorrhagic presentations were more common in AVM with cortical and subcortical location, a nidus of more than5cm, angiomatous change, dural supply, both superficial and deep venous drainage, kinking, and stasis (p <0.05-0.001). CONCLUSION: The angio-architechture of AVM with hemorrhage correlated with clinical symptomaticpresentation. Analysis of the patterns of angioarchitectureis useful for prognosis and in deeiding the direetionof freatment.

Local Intracranial Intraarterial Thrombolytic Therapy in Acute Cerebral Infarction

PURPOSE: To evlauate the efficacy of direct intracranial intraarterial thrombolytic therapy in patients withacute atherothrombotic and embolic stoke. MATERIALS AND METHODS: Forty-one patients with cerebral thromboembolic disease, all in the area of the middle cerebral artery and including two cases of internal carotid artryocclusion, were treated with microcatheter-directed local intraarterial thrombolysis, using 180,000 to 1,000,000unit urokinase and 15 to 50mg of tissue plasminogen activator (tPA). The time elapsed before treatment ranged from260 to 470 minute (mean : 380 minutes). The effect of treatment was assessed by cerebral angiography, by CT and bythe clinical outcome. RESULTS: For 25 patients (61%), complete vessel recanalization was successful, In eightand three cases, respectively, the result was partial recanalization and residual stenosis. In 21 patients (51%),both acute neurologic and functional outcomes improved significantly within 24 hours and in 92% of patients, within one month. Hemorrhagic transformations occured in five patients (12.2%), and in five others there were high density lesions around the basal ganglia and temporal lobe, which was cleared on CT within 24 hours This suggested transient extravasation of the contrast media rather than true hemorrhage. tPA showed better results than urokinase in terms of the rate of recanlization (68.7% vs 56.7%) and the occurrence of hemorrhagic infarction(6.3%vs 16.9%). CONCLUSIONS: Local intraarterial cerebral thrombolysis is thought be an effective method in the treatment of acute brain infarction, but in some patients may cause intracerebral hemorrhage in some patients.