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The incidence of subarachnoid hemorrhages (SAHs) in Japan has recently decreased. However, trends in the annual rates of unruptured cerebral aneurysms (UCAs) are unclear because calculations based on follow-up periods are limited to patients with ruptured cerebral aneurysms. We aimed to clarify current trends in the estimated annual rupture rates of UCAs in Japan and to identify the most relevant contributing factors. We analyzed data from the Japanese Ministry of Health, Labour and Welfare and records of the Japan Neurosurgical Society. The estimated annual rupture rates of UCAs between 2003 and 2018 were calculated according to age-adjusted mortality rates of SAH and number of treated ruptured cerebral aneurysms (RCAs). We estimated trends in annual rupture rates using sensitivity analysis and assessed associations between estimated annual rupture rates and the prevalences of hypertension and current smoking. The estimated annual rupture rate of UCAs significantly decreased from 1.44 to 0.87% and from 0.92 to 0.76%, respectively, in terms of age-adjusted mortality rates of SAH and number of treated RCAs (p < 0.001). The range of changes in estimated annual rupture rates of UCAs was - 1.13%‒0.83%, representing a declining UCA trend of 88%. The estimated annual rupture rates of UCAs declined by 0.02-0.10% and 0.01-0.05% with every percent decrease in hypertension and current smoking prevalence, respectively. The estimated annual rupture rate of UCAs has recently decreased in Japan, possibly due to a decrease in the prevalence of hypertension rather than smoking., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Diagnostic image analysis for unruptured cerebral aneurysms using artificial intelligence has a very high sensitivity. However, further improvement is needed because of a relatively high number of false positives. This study aimed to confirm the clinical utility of tuning an artificial intelligence algorithm for cerebral aneurysm diagnosis. We extracted 10,000 magnetic resonance imaging scans of participants who underwent brain screening using the "Brain Dock" system. The sensitivity and false positives/case for aneurysm detection were compared before and after tuning the algorithm. The initial diagnosis included only cases for which feedback to the algorithm was provided. In the primary analysis, the sensitivity of aneurysm diagnosis decreased from 96.5 to 90% and the false positives/case improved from 2.06 to 0.99 after tuning the algorithm (P < 0.001). In the secondary analysis, the sensitivity of aneurysm diagnosis decreased from 98.8 to 94.6% and the false positives/case improved from 1.99 to 1.03 after tuning the algorithm (P < 0.001). The false positives/case reduced without a significant decrease in sensitivity. Using large clinical datasets, we demonstrated that by tuning the algorithm, we could significantly reduce false positives with a minimal decline in sensitivity., (© 2023. The Author(s).)

Objective: Some aneurysmal subarachnoid hemorrhage (SAH) patients are delayed in their presentation. This can cause a washout of the subarachnoid hematoma and a potential misdiagnosis. As a result, they may suffer rerupture of the aneurysm and preventable deterioration. We investigated the factors that influence delayed SAH presentation., Methods: Aneurysmal SAH patients treated at 9 stroke centers from 2002 to 2020 were included. Age, gender, pre-SAH modified Rankin scale, World Federation of Neurological Surgeons grade, Fisher group, day of presentation, aneurysm treatment method, past history of cerebral stroke, comorbidity of hypertension and/or diabetes mellitus, and modified Rankin scaleat discharge were assessed retrospectively. We formed 2 groups based on the day of presentation after the onset of SAH: day 0-3 (early) and other (delayed). Logistic regression analyses detected the factors that influenced the day of presentation and outcome for SAH. A P- value <0.05 was considered significant., Results: Delayed presentation comprised 282 cases (6.3%) of 4507 included cases. Logistic regression analyses showed that patients in an urban area, of male gender, low WFNS grade and low Fisher group correlated significantly with a delayed presentation. But delayed presentation did not influence outcome at discharge., Conclusions: Area of residency and gender correlated with delayed presentation after SAH in Japan. Urbanization, male gender, and mild SAH lead patients to delay presentation. The factors underlying these tendencies will be analyzed in a future prospective study., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Although chronological age is associated with mortality and morbidity after surgery for unruptured cerebral aneurysms (UCAs), there is little evidence regarding an association between the simplified 5-factor modified frailty index (mFI-5) and postoperative outcomes based on age group., Objective: To investigate the association of the mFI-5 score with worse outcomes, mortality, and complications in patients after surgery for UCA by chronological age groups using a Japanese national database., Methods: This study included 32 902 patients with UCAs enrolled in a Japanese national database between 2011 and 2015. Age group (younger than 65 years, 65-74 years, and 75 years or older), sex, UCA location, treatment, medications, Barthel Index (BI), medical history, mFI-5 score, and in-hospital mortality and complications were evaluated. We identified risk factors for worsening BI score, in-hospital mortality, and overall postoperative complications in each age group., Results: In total, 14 465 patients were enrolled in this study. Multivariable analysis showed that elderly groups and patients with an mFI-5 score ≥2 items were associated with worsening BI scores (odds ratio 1.95; 95% CI 1.52-2.51) and in-hospital complications (odds ratio 1.79; CI 1.49-2.15), despite having no association with in-hospital mortality. Multivariable analysis by age groups showed that the mFI-5 score ≥2 items was associated with in-hospital complications in all age groups, unlike chronological age in patients younger than 74 years., Conclusion: The mFI-5 score was a more useful associated factor of in-hospital complications than chronological age in patients younger than 74 years undergoing surgery for UCA., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Congress of Neurological Surgeons.)

The "Izumo Study" revealed the incidence rate of subarachnoid hemorrhage (SAH) in Izumo City, Shimane Prefecture, Japan, from 1980 to 1998. However, no study has been published regarding the incidence of SAH in Shimane Prefecture after 1998. Most studies reporting the incidence of SAH in Japan have been conducted before 2000, although a few have been reported after 2000. This study aimed to assess the estimated age-adjusted incidence rate (AAIR) of SAH in Shimane Prefecture after 1998, following the Izumo Study. A retrospective study was conducted to identify the estimated AAIR of SAH in Shimane Prefecture, using the age-adjusted SAH mortality rate for this population from 1999 to 2017 and assuming that the case-fatality rate of SAH decreased by 0.7% annually from 45% in 1999 to 32.4% in 2017. We used linear regression analysis for trend to the estimated AAIR of SAH. Sensitivity analyses were also conducted by various case-fatality rates of SAH using assuming case-fatality rate based on previous reports. The estimated AAIR of SAH in Shimane Prefecture declined from 33.6 (95% confidence interval [CI]: 29.7-37.9) per 100,000 person-years in 1999, by 26.5%, to 24.7 (95% CI: 21.4-28.5) in 2017 (p < 0.01, r = 0.58). Declining trend of incidence rate of SAH in Shimane Prefecture from 1999 to 2017 was confirmed in this study.

This is a post hoc multivariate analysis of the modified World Federation of Neurosurgical Societies (WFNS) grading project, multicenter prospective observational study including 38 neurosurgical institutions across Japan. Japan Neurosurgical Society WFNS grading committee conducted a modified WFNS grading project as a nationwide prospective registry study. We investigate the clinical outcome of both surgical and endovascular interventions after aneurysmal subarachnoid hemorrhage (SAH) in Japan. A total of 792 patients received surgical intervention and 417 patients received endovascular treatment. Eight hundred patients were female, and 409 patients were male. The mean age was 61.5 ± 13.7 years. At 3 month follow-up, there was no statistically significant difference in good clinical outcome between surgical (68.2%) and endovascular (60.9%) group (odds ratio, 0.89; 95% confidence interval, 0.68-1.16; p = 0.381). Unfavorable outcome rate was 31.8% (238 patients) in the surgical group and 39.1% (154 patients) in the endovascular group. Male, elderly people, modified Rankin scale condition before onset, high-grade modified WFNS clinical grading scale, intracerebral hematoma, posttreatment normal pressure hydrocephalus, and neurological deficit due to symptomatic vasospasm were risk factors for the clinical outcome. Treatment modality was not a statistical factor for clinical outcomes. Surgical clipping has still a major role in the management of SAH in Japan. The present study was not a randomized controlled study, but clinical outcome is not influenced by treatment modalities.

There are no scoring methods for optimal treatment of patients with aneurysmal subarachnoid hemorrhage (aSAH). We developed a scoring model to predict clinical outcomes according to aSAH risk factors using data from the Japan Stroke Data Bank (JSDB). Of 5344 patients initially registered in the JSDB, 3547 met the inclusion criteria. Patients had been diagnosed with aSAH and treated with surgical clipping or endovascular coiling between 1998 and 2013. We performed multivariate logistic regression for poor outcomes at discharge, indicated by a modified Rankin Scale (mRS) score >2, and in-hospital mortality for both treatment methods. Based on each risk factor, we developed a scoring model assessing its validity using another dataset of our institution. In the surgical clipping group, scoring criteria for aSAH were age >72 years, history of more than once stroke, World Federation of Neurological Societies (WFNS) grades II-V, aneurysmal size >15 mm, and vertebrobasilar artery (VBA) aneurysm location. In the endovascular coiling group, scoring criteria were age >80 years, history of stroke, WFNS grades III-V, computed tomography (CT) Fisher group 4, and aneurysmal location in the middle cerebral artery (MCA) and anterior cerebral artery (ACA). The rates of poor outcome of mRS score >2 in an isolated dataset using these scoring criteria were significantly correlated with our model's scores, so this scoring model was validated. This scoring model can help in the more objective treatment selection in patients with aSAH.

Background: The etiology and background factors which cause decreases in the size of ruptured intracranial aneurysms remain unclear., Objective: To clarify the age- and sex-related differences in aneurysmal subarachnoid hemorrhage (SAH) based on a 35-year-old hospital database and demographic data., Methods: A database of patients admitted to our hospital with aneurysmal SAH from 1983 to 2017 was split into 5-year intervals and analyzed. Demographic data of the general population were also analyzed for reference., Results: Altogether, 1,523 aneurysmal SAH events were enrolled in the analysis. Age (p<0.001), proportion of elderly patients ≥ 65 years old (p<0.001), female sex (p=0.005), very small aneurysms less than 5 mm (p<0.001), and the yearly-averaged number of fatal events showed increasing trends. The proportion of aneurysm size of 10 mm or more (p = 0.011) and the yearly-averaged population of Shimane prefecture (p < 0.001) showed declining trends. In the subgroup analyses, the proportion of very small aneurysms was found to increase significantly in the non-elderly male and elderly female subgroups. The proportion of large aneurysms (10 mm or more) decreased in the non-elderly subgroup (p<0.05). As for the elderly subgroups, the yearly-averaged number of events did not show a significant tendency, although the yearly-averaged population of Shimane prefecture showed an increasing trend., Conclusion: We found an increasing trend in the prevalence of very small aneurysms in elderly females. Recent aging may contribute to this trend. The number of aneurysmal SAH events was confirmed to not increase, despite the increased aging population of Shimane prefecture., Competing Interests: Declaration of Competing Interest The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

There has never been evidence for aneurysmal subarachnoid hemorrhage (aSAH) by endovascular coiling compared to surgical clipping with all grade. The present study and meta-analysis aimed to clarify the in-hospital mortality and poor outcome in the nationwide databases of patients with all grade aSAH between them. The outcome of modified Rankin scale (mRS) at discharge was investigated according to the comprehensive nationwide database in Japan. The propensity score-matched analysis was conducted among patients with aSAH in this database registered between 2010 and 2015. Meta-analysis of studies was conducted based on the nationwide databases published from 2007 to 2018. According to this propensity score-matched analysis, no significant association for poor outcome of mRS > 2 was shown between surgical clipping and endovascular coiling (47.7% vs 48.3%, p = 0.48). However, significantly lower in-hospital mortality was revealed after surgical clipping than endovascular coiling (7.1% vs 12.2%, p < 0.001). Meta-analysis of propensity score-matched analysis in the nationwide database showed no significant association for poor outcome at discharge between them (odds ratio [OR], 1.08; 95% confidence interval [CI], 0.93 to 1.26; p = 0.31). Meta-analysis of propensity score-matched analysis for in-hospital mortality was lower after surgical clipping than after endovascular coiling, however, without significant difference (OR, 0.74; 95% CI, 0.52 to 1.04; p = 0.08). Further prospective randomized controlled study with all grade aSAH should be necessary to validate the in-hospital mortality and poor outcome.

Background: This study aimed to compare the functional outcome at discharge for unruptured cerebral aneurysms (UCAs) between surgical clipping and endovascular coiling in total, nonelderly (<65 years), and elderly (≥65 years) patients by nonbiased analysis based on a national database in Japan., Methods: A total of 15,671 patients with UCA were registered in the Diagnosis Procedure Combination, the nationwide database, from 2010 to 2015 in Japan. The outcome of the Barthel Index (BI) at discharge was investigated, and propensity score-matched analysis was conducted in total, nonelderly, and elderly patient groups., Results: Propensity score-matched analysis found no significant difference for in-hospital mortality between the 2 treatment methods in the total and both age-groups. The rate of morbidity of BI <90 at discharge was higher after surgical clipping than after endovascular coiling in the total (4.9% vs. 3.9%; P = 0.040; risk difference, -1.0%; 95% confidence interval, -3.6 to 2.3%) and the elderly age-group (8.1% vs. 5.0%; P < 0.001; risk difference, -3.1%; -4.8% to 1.5%), however, no significant association between the 2 treatment methods (2.4% vs. 2.6%; P = 0.67; risk difference, 0.22%; -0.79 to 1.22%) was found in the nonelderly group., Conclusions: In elderly patients with UCA, a better outcome at discharge after endovascular coiling was found. However, no significantly different functional outcome at discharge between surgical clipping and endovascular coiling for UCA in nonelderly patients was confirmed by propensity score-matched analysis from a nationwide database in Japan., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: There has been no precise guide for treatment management of aneurysmal subarachnoid hemorrhage (aSAH) based on the patient's age and treatment method. This study clarifies each risk management for aSAH according to age and treatment method listed in a nationwide database., Methods: We compared 2 groups of patients (nonelderly, <65 years; elderly, ≥65 years) who underwent surgical clipping or endovascular coiling and were registered in a nationwide database in Japan from 2010 to 2015. The odds ratio (OR) and 95% confidence interval (CI) of each risk factor were calculated through multivariate logistic regression analysis for poor outcome according to a modified Rankin Scale score >2 at discharge for each group., Results: In all groups, the risk factors for poor outcome were older age, male sex, neurologic grade on admission, diabetes mellitus, and use of anticoagulation drugs. Inverse risk factors were a high-volume hospital, academic hospital, hypertension, and use of an antiplatelet drug (OR, 0.63-0.81; 95% CI, 0.56-0.88). Chronic heart disease was also a risk factor, but use of a statin drug (OR, 0.85-0.87; 95% CI, 0.76-0.97) and location other than on the anterior communicating artery (OR, 0.74-0.80; 95% CI, 0.67-0.91) were inverse risks in both the elderly and the endovascular coiling groups., Conclusions: Management for patients with aneurysmal subarachnoid hemorrhage was recommended in high-volume and academic institutes with the administration of antiplatelet drugs and consideration of several risk factors. Elderly patients undergoing endovascular coiling might be better given a statin drug, and patients with chronic heart failure or an anterior communicating artery aneurysm should be treated more carefully., (Copyright © 2019. Published by Elsevier Inc.)

Background: This study aimed to clarify the risk factors of treatment for unruptured cerebral aneurysms (UCAs) in elderly patients by comparing the morbidity at discharge between surgical clipping and endovascular coiling in nonelderly (<65 years) and elderly (≥65 years) patients based on a national database in Japan., Methods: A total of 36,017, including 15,671 patients with UCA after exclusion of unknown location, were registered in the Diagnosis Procedure Combination, the nationwide database, from 2010 to 2015 in Japan. Outcome of Barthel Index at discharge was investigated and multivariate logistic regression analysis identified risk factors for morbidity of Barthel Index <90 at discharge in nonelderly and elderly patient groups., Results: Risk factors for morbidity at discharge were basilar artery aneurysm compared with internal carotid artery (ICA), diabetes mellitus (odds ratio [OR], 2.0-2.5; 95% confidence interval [CI], 1.6-3.7), antiplatelet drug, and anticoagulation drug; however, highest hospital volume compared with lowest was an inverse risk factor in both age groups. Endovascular coiling (OR, 0.4; 95% CI, 0.3-0.5) was a significantly inverse risk in the elderly group. Anterior communicating artery aneurysm compared with ICA was a significant risk (OR, 1.6; 95% CI, 1.0-2.6) in the nonelderly group; on the other hand, anterior communicating artery aneurysm (OR, 0.7; 95% CI, 0.5-0.95) and middle cerebral artery aneurysm (OR, 0.6; 95% CI, 0.5-0.8) compared with ICA were significantly inverse risks in the elderly group., Conclusions: Endovascular coiling after control of diabetes mellitus was recommended for the treatment of UCA in elderly patients. The ICA location of aneurysm in the elderly should be paid attention as the treatment risk., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The characteristics of cerebral aneurysms in Japan differ from other countries in the higher incidence of unruptured cerebral aneurysm detected by brain check-up screening, higher rupture rate of unruptured cerebral aneurysm, higher incidence of subarachnoid hemorrhage, and superior outcome after subarachnoid hemorrhage based on meta-analysis. Head shape, genetic features, environmental factors, demographics, and medical system in Japan are also different from other countries. Unruptured cerebral aneurysms are 2.8 times more likely to rupture in Japanese than western aneurysms, resulting in the highest incidence of subarachnoid hemorrhage in the world. The exact and specific mechanisms of de novo, growth, and rupture of cerebral aneurysms have not been elucidated. Investigations will contribute to the understanding of cerebral aneurysms and subarachnoid hemorrhage worldwide. Some features of cerebral aneurysm in Japan are discussed for possible research guidance in the elucidation of the predominance of subarachnoid hemorrhage in Japan.

The Japanese population features the highest rate of elderly individuals worldwide. However, the difference of actual age indication for surgical clipping (SC) and endovascular coiling (EC) has never reported. We clarified the effect of actual age on poor outcome at discharge in patients by each treatment for ruptured cerebral aneurysm according to the Japanese Stroke Data Bank. A total of 3593 patients with ruptured saccular cerebral aneurysm were treated by SC and/or EC between 2000 and 2013. The effect of actual age on poor outcome (modified Rankin scale [mRS] score > 2) at discharge was evaluated by the cutoff age using receiver operating characteristic analysis for each treatment. There were 2666 cases in the SC group and 881 cases in the EC group. The cutoff age for poor outcome was 3 to 9 years older for EC than for SC. The gap of cutoff age between two treatments was 3 years shorter in mild subarachnoid hemorrhage than severe cases. The gap of cutoff age between two treatments was 7 years in elderly patients over 65 years old. The cutoff age was 78 years old for both SC and EC in elderly female patients. In conclusion, the cutoff age for poor mRS score > 2 was 3 to 9 years older for EC than for SC. Actual age was one of the indications for elderly patients to achieve the optimum outcome; however, the treatment indication should be carefully considered based on the condition in each country.

Dissecting aneurysms in the anterior cerebral artery (ACA), although rare, can cause ischemic and/or hemorrhagic stroke. Hemorrhagic dissecting aneurysms in the A1 portion of the ACA are often associated with a poor prognosis. We retrospectively investigated three rare cases of hemorrhagic dissecting aneurysms in the A1 portion. Dissecting aneurysms were diagnosed by carotid angiography or computed tomography angiography to visualize morphological changes in the vessel. All patients presented with diffuse subarachnoid hemorrhage. In one case, computed tomography angiography performed at the onset of the subarachnoid hemorrhage revealed fusiform dilatation at the right ACA (A1), which did not appear on a magnetic resonance angiogram obtained 1 year prior to the onset of the subarachnoid hemorrhage. In the other two cases, A1 dissecting aneurysms were diagnosed from a growing aneurysmal bulge revealed at a non-bifurcated site via repeated carotid angiography. Two patients underwent surgical intervention (trapping or clipping), and their outcome was favorable, whereas the third patient died of delayed rebleeding before receiving surgical treatment. Hemorrhagic dissecting aneurysms in the A1 portion cause severe subarachnoid hemorrhage. Surgical treatments that include revascularization are necessary to prevent rebleeding, and direct surgery is recommended, particularly at the A1 portion.

The outcomes at discharge for ruptured cerebral aneurysms after subarachnoid hemorrhage (SAH) were investigated using data from the Japanese stroke databank. Among 101,165 patients with acute stroke registered between 2000 and 2013, 4693 patients had SAH caused by ruptured saccular aneurysm. Of these, 3593 patients (1140 men and 2453 women; mean age 61.3 ± 13.7 years) were treated by surgical clipping (SC) and/or endovascular coiling (EC). The outcomes of modified Rankin scale (mRS) at discharge were compared between the SC and EC groups. There were 2666 cases in the SC group, 881 cases in the EC group, and 46 cases in the SC and EC group. The rates of poor outcome of mRS > 2 were 33.0 and 45.5% in the SC and EC groups (p < 0.05), respectively. Cases were selected using two types of criteria compatible with both treatments. Under the first compatible criteria, the rates of poor outcome of mRS > 2 were 18.9 and 24.8% in the SC and EC groups (p < 0.05), respectively. Under the second compatible criteria, the rates of poor outcome of mRS > 2 were 16.0 and 14.8% in the SC and EC groups (p = 0.22), respectively. No significant differences were found in clinical characteristics or outcomes between the two groups. Multivariate analysis of aneurysmal SAH revealed no significant risk for poor outcome associated with the treatment method. The present study was not a randomized controlled study, but no significant differences in mRS at discharge were found between SC and EC in the Japanese stroke databank.

A 56-year-old man presented with a giant serpentine aneurysm arising from the middle cerebral artery (MCA) manifesting as right hemiparesis and motor aphasia. Magnetic resonance imaging and digital subtraction angiography identified the giant serpentine aneurysm arising from the MCA. The patient was treated surgically. Temporary clipping of the distal channel induced thrombosis in the vascular channel, and the thrombosis was aspirated with an ultrasonic suction device after superficial temporal artery-MCA anastomosis. This case shows that initial occlusion of the distal channel is effective to treat giant serpentine aneurysm.

Treatment of ruptured dissecting aneurysm of basilar trunk (BADAN) has been controversial yet. We report a case of ruptured BADAN successfully treated with endovascular occlusion of the bilateral vertebral artery (VA) proximal to posterior inferior cerebellar artery (PICA), allowing retrograde flow via the posterior communicating arteries to basilar artery. A 58-year-old woman who had subarachnoid hemorrhage was treated with endovascular occlusion of the right VA in acute stage after ballon occlusion test (BOT) of the right VA. Because following BOT of the left VA showed conscious level down, left VA could not be occluded. Follow-up angiography after 26 days revealed regrowth of BADAN. So left VA occlusion was tolerable by BOT after 1 month, we performed endovascular occlusion of the left VA proximal to PICA. She discharged with no neurological deficit after 3 months. Postoperative angiograms 3 months after onset showed complete healing of the aneurysm. The follow-up MRA at 19 months showed no recurrence. We discussed the therapeutic strategy of ruptured BADAN. Flow reverse therapy of bilateral VA occlusion by endovascular method for ruptured BADAN is one of the effective therapy.

In the distal posterior inferior cerebellar artery (PICA), saccular aneurysms originating at the first proximal segment, anterior medullary segment (AMS), are unusual but important due to the presence of critical perforators that branch off the PICA and supply the lower brainstem. Because the anatomy of the PICA varies, no standard treatment strategy has been agreed upon to date. We successfully treated 2 patients with open surgery. One was a 53-year-old man who presented with Hunt-Hess grade 2 subarachnoid hemorrhage (SAH). Cerebral angiography revealed an irregular fusiform AMS aneurysm extending to the lateral medullary segment. Intraoperative inspection showed some perforators to the brain stem branching from just proximal and distal to the aneurysm. The patient underwent aneurysmal trapping and occipital artery-PICA anastomosis to preserve perforators flow, and was discharged without any neurological deficits. Another patient, a 74-year-old woman, was transferred to our institute because she suddenly became comatose. She was found to have a ruptured saccular AMS aneurysm. On the 15th day after the event, she underwent successful aneurysmal clipping preserving perforators by surgical inspection. As both patients manifested intra-aneurysmal thrombosis, we suggest that patients presenting with AMS aneurysms that display unusual features require careful management and judicious choice of treatment. Based on our experience we suggest that direct surgery, which facilitates the identification of perforators and allows for revascularization, is the appropriate treatment choice in patients who present with this entity.

A 65-year-old woman presented with a ruptured dissecting aneurysm of the M3 portion of the middle cerebral artery (MCA) manifesting as disturbance of consciousness and motor aphasia. Computed tomography revealed subarachnoid hemorrhage. Emergent angiography demonstrated segmental aneurysmal dilatation of the M3 portion of the left MCA. Infectious aneurysm was excluded. Surgery was performed to prevent repeated hemorrhage from the aneurysm. The lesion was excised and flow to the distal MCA was preserved with an anastomosis of the superficial temporal artery to the MCA. Histological examination confirmed that the aneurysmal dilatation was due to arterial dissection caused by disruption of the internal elastic lamina. Distal dissecting aneurysm may occur in the absence of infectious disease. Such ruptured distal dissecting aneurysm should preferably be treated surgically in the acute stage, immediately after detection of the aneurysm. The parent artery of the proximal and distal sides of the aneurysm should be trapped because of the probable weakness of the arterial wall, and bypass surgery performed to preserve the distal circulation.

Dissecting aneurysms rarely occur in the middle cerebral artery (MCA). Furthermore, recurrent subarachnoid hemorrhage from ruptured dissecting aneurysms is rare with no published report of subsequent rupture after treatment by the clip on wrap method. The case reported is a 41-year-old man with subarachnoid hemorrhage. Angiography demonstrated aneurysm at the right M2 portion. We performed surgery to prevent rebleeding during the acute stage. Surgery revealed a discolored protrusion of the arterial wall of the lesion. The lesion was clipped on wrapping with Bemsheet. At one month postoperatively, angiography showed neither aneurysmal formation nor stenosis at the right M2, but after 5 months a subsequent rupture occurred. Angiography demonstrated pseudoaneurysm formation at the same portion of the right M2. The lesion was trapped with anastomosis of the superficial temporal artery (STA) to the MCA. He was discharged following a good recovery. The rate of subsequent rupture in ruptured dissecting aneurysm in the MCA is 14.3% in published papers. Acute surgery must be performed to prevent the risk of re-rupture. In our single case report, trapping was effective treatment.

A 65-year-old woman presented with multiple dissecting aneurysms of the anterior cerebral artery (ACA) manifesting as hemiparesis on the right with dominance in the lower extremity. Computed tomography revealed hematoma in the left frontal lobe, corresponding to the area perfused by the callosomarginal artery. Initial angiography showed string sign and occlusion in the distal portion of the left callosomarginal artery and abnormal feeding suggesting double lumen of the A2 portion of the left ACA. The patient was treated conservatively under a diagnosis of multiple spontaneous dissecting aneurysms of the left ACA. Repeat angiography on Day 8 showed improvement of the string sign and occlusion in the left callosomarginal artery, and change of the double lumen of the A2 portion into string sign. Further angiography on Day 36 showed normalization of the left callosomarginal artery and improvement of the string sign in the A2 portion. Multiple spontaneous dissecting aneurysms of the ACA are extremely rare. Serial angiography beginning in the early stage will be important for correct diagnosis.

We present a rare case of a Rathke's cleft cyst in association with a ruptured aneurysm of the anterior cerebral artery (ACA). A 44-year-old man suffered from sudden onset of headache. Initial computed tomographic (CT) scan revealed a high-density mass lesion in the suprasellar region and a diffuse high-density area in the basal cistern. Using emergent magnetic resonance imaging (MRI), we found a cyst showed homogeneously high and iso-intensity on T1 and T2-weighted image, respectively. The cyst showed no enhancement of the cyst wall, but on Gd-DTPA, it was shown to compress the normal pituitary gland. Angiography showed an aneurysm at the A1 portion of the left ACA. Based on/these findings, we were able to diagnose Rathke's cleft cyst and a ruptured aneurysm. An operation was performed through the interhemispheric approach. The suprasellar cystic mass compressed the optic nerves and chiasm upward. Neck clipping of the aneurysm and opening of the cyst were performed. We confirmed the cause of the subarachnoid hemorrhage as being a ruptured aneurysm at the A1 portion of the left ACA. Histological diagnosis was Rathke's cleft cyst. Postoperative course was uneventful. There has been only one reported case of Rathke's cleft cyst in association with a ruptured aneurysm. When we encounter a case presenting subarachnoid hemorrhage with suprasellar mass and intracerebral aneurysm, we must discriminate between ruptured aneurysm and pituitary apoplexy in the acute stage as the cause of the subarachnoid hemorrhage. If the mass is Rathke's cleft cyst, we speculate that the cause of the subarachnoid hemorrhage is a ruptured aneurysm, because there are no reports of Rathke's cleft cyst with subarachnoid hemorrhage.

We present a rare case of a dissecting aneurysm of the left anterior cerebral artery (ACA) with persistent pearl & string sign on cerebral angiograms over a period of 8 years. A 43-year-old woman with disturbance of consciousness and right sided hemiparesis was conservatively treated. Computed tomographic (CT) scan revealed a low-density area in the left frontal lobe. Initial angiography, which was performed at 6 months after the onset, showed a pearl & string sign at the A2 portion of the left ACA. After 8 years, repeat angiography again showed persistent pearl & string sign at the same portion of the left ACA. We discussed the changes in findings usually obtained in cerebral angiography concerning dissecting aneurysms in ACA.

We report two cases with embolization (coil embolization) using Guglielumi detachable coils of residual aneurysms following incomplete neck clipping. The first case, a 75-year-old woman suffered from a subarachnoid hemorrhage due to the rupture of a left internal carotid posterior communicating aneurysm in June, 1997. Neck clipping of the aneurysm was performed at day 1. Follow-up angiogram at day 7 showed a residual aneurysm involving the dome of the initial aneurysm. We performed coil embolization of the residual aneurysm following the angiogram. Almost complete obliteration of the aneurysm lasted during the follow-up period of two and a half years. The second case, a 71-year-old woman suffered from a subarachnoid hemorrhage due to the rupture of a right internal carotid posterior communicating aneurysm in May, 1999. Neck clipping of the aneurysm was performed at day 1. Follow-up angiogram at day 7 showed a residual aneurysm involving only a part of the initial aneurysm near the neck. Because no spontaneous thrombosis of the residual aneurysm was obtained after 2 months, we performed coil embolization of the residual aneurysm. Almost complete obliteration of the aneurysm lasted during the follow-up period of 7 months. These patients were discharged with good performance status. We consider the morphologic feature of the residural aneurysm to be most important for determining when to perform coil embolization of such residual aneurysms.

Temporary vessel occlusion (TO) for aneurysmal clipping is an effective technique to facilitate dissection between aneurysm and parent vessels, and to place a permanent clip at the aneurysmal neck precisely. However, several unsolved problems remain regarding the overall safety and risk resulting from this technique. The authors examined a series of patients in whom mannitol 500 ml, tocopherol acetate 500 mg, and phenytoin 500 mg were administered intravenously as ischemic protection during TO for the aneurysmal clipping. The study comprises a nonconcurrent retrospective analysis of 144 consecutive aneurysm clippings performed with the aid of intentional TO at the Hiroshima Prefectural Hospital from 1985 to 1995. To identify technical and patient-specific risk factors for perioperative stroke, factors studied included duration, location of the temporary clip application, number of occlusive episodes, patient sex, age, and preoperative neurological status, timing of operation, as well as postoperative, temporary or permanent, neurological deficits (ND) due to TO were used. Overall frequency of postoperative ND due to TO manifested clinically and radiologically were 9.0% and 9.7%, respectively. In both univariate and multivariate analysis there were no significant factors relevant to the ND. However, duration of the temporary occlusion time over 20 minutes was the factor most influential on the ND due to TO. Duration of the temporary occlusion time was shown to have no link with outcome. Based on our findings the authors conclude that temporary vessel occlusion within 20 minutes with anti-ischemic drugs is a relatively safe adjunct to aneurysmal surgery.

We report a case of Rathke's cleft cyst associated with anterior communicating artery aneurysm. The patient was 60-year-old woman who developed visual disturbance two months before admission to our hospital. Visual acuity on the right was 0.06 and on the left was 0.08. The visual fields showed a complete temporal hemianopsia on the left eye and an incomplete temporal hemianopsia of the right eye with a central defect of the temporal visual field. CT and MR imagings showed an intra- and suprasellar mass lesion with no enhancement. Angiography showed bilateral A1 elevations and anterior communicating artery aneurysm. The operation was performed through interhemispheric approach. Suprasellar cystic mass compressed upward the optic nerves and chiasm, and aneurysmal dome stuck in the central region of chiasm. This anatomical disorders affected to the optic chiasm resulted in a rare visual field defect. Neck clipping of aneurysm and opening of the cyst were performed. A diagnosis of Rathke's cleft cyst was made. Following surgery, her visual fields resolved but she suffered from diabetes insipidus.

The purpose of this study was to investigate the indication of direct early surgery for elderly cases aged over 70 years with ruptured intracranial aneurysms. The result of early surgical treatment in 39 elderly cases was analyzed and was compared with that of conservative treatment in 39 elderly patients. According to the multiple logistic analysis, surgery was only significant factor influenced the outcome, however, Hunt & Kosnik grade (HKG), activity of daily life (ADL) before subarachnoid hemorrhage (SAH) and past history were related to the outcome. The outcome in the direct early surgical group statistically correlated (p < 0.05) with preoperative HKG, although the outcome in the conservative group did not correlate with HKG. The outcome in conservative group was miserable because of rerupture or poor preoperative neurological grade. The indication of direct early surgery for elderly cases with ruptured intracranial aneurysms should be considered as follows, HKG 1 to 3, ADL before SAH 1, no or minor past history and age under 84 since most elderly patient was 84 in our series. Direct early surgery in elderly patients seems to improve the outcome under these indications.

Magnetic resonance angiography (MRA) can be divided into two types: namely, the phase-contrast (PC) method and the time-of-flight (TOF) method. The purpose of this study is to determine which method is better suited to demonstrate cerebral aneurysms. In a total of 27 cerebral aneurysms confirmed by cerebral angiography, both three-dimensional (3-D) PC and 3-D TOF methods were performed, and the corresponding findings were compared with conventional cerebral angiographic findings. Aneurysm visualization was grouped into three categories: "good" when clearly distinguishable, "fair" if distinguishable when reconstructed, and "poor" if completely undistinguishable. All MRAs were independently interpreted by two neurosurgeons in our institute. Sensitivity was 92.6% when MRA was performed with the TOF method, whereas it was 70.4% when performed with the PC method. In conclusion, the TOF method was more useful for demonstrating the aneurysms than the PC method due to its higher spatial resolution and shorter imaging time.