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Objective: Surgical clipping is a major treatment modality in treating cerebral aneurysms. However, in magnetic resonance (MR) imaging, susceptibility artifact due to metal clips impedes postoperative assessments of clipped aneurysms, parent arteries, and adjacent parenchyma. Our goal was to develop an MR-compatible aneurysm clip. Methods: To reconcile mechanical/biologic properties with MR demands, we fabricated a prototypic clip (ZC: straight, 9-mm long), made of zirconia (body) and polyurethane (spring). Mechanical properties, closing forces, open-blade width, and artifact volumes (in vitro and in vivo) by 3T MR imaging of ZC and currently available metal clips (Yasargil [YC: curved, 8.3-mm long] and Sugita [SC: straight, 10-mm long]) were compared, using a canine venous pouch aneurysm model for in vivo study. Results: Respective closing force (N) values, measured at 1-mm and 8-mm distances from blade tip, were 2.09 and 3.77 in YC, 1.85 and 3.04 in SC, and 2.05 and 4.60 in ZC. Maximum open-blade widths (mm) were 6.8, 9.0, and 3.0 in YC, SC, and ZC, respectively. In vitro artifact volumes of YC and ZC were 26.0- and 1.9-fold greater than corresponding actual volumes. In vivo artifact volumes of YC, SC, and ZC were 21.4-, 29.4-, and 2.6-fold greater than actual volumes. Conclusion: Compared with two clips in current use, our prototypic clip showed the least susceptibility artifact, with satisfactory closing forces. However, its narrow open-blade width was a weak point. Further experimentation is needed for design refinements and durability testing before human application is feasible.

Background and Purpose— The surgical outcomes of adult moyamoya disease are rarely reported. We aimed to evaluate the long-term outcomes of combined revascularization surgery in patients with adult moyamoya disease. Methods— Combined revascularization surgery consisting of superficial temporal artery–middle cerebral artery anastomosis with encephalodurogaleosynangiosis was performed on 77 hemispheres in 60 patients. Clinical, angiographic, and hemodynamic states were evaluated retrospectively using quantitative methods preoperatively and postoperatively in the short-term (≈6 months) and long-term (≈5 years) periods. The mean clinical follow-up duration was 71.0±10.1 months (range, 60–104 months). Results— Clinical status improved until 6 months after surgery and remained stable thereafter, as assessed by the Karnofsky Performance Scale and modified Rankin Scale. The revascularization area relative to supratentorial area significantly increased in the long-term period compared with that in the short-term period (54.8% versus 44.2%; P P P =0.219). The annual risks of symptomatic hemorrhage and infarction were 0.4% and 0.2%, respectively, in the operated hemispheres. Conclusions— Combined revascularization surgery resulted in satisfactory long-term improvement in clinical, angiographic, and hemodynamic states and prevention of recurrent stroke.

Objective: The optimal consensus over treatment of incidental small paraclinoid unruptured intracranial aneurysm (UIA) remains controversial. The aim of this study was to reveal the natural history of small paraclinoid UIA with the goal of informing a treatment plan. Methods: A total of 344 patients harboring 364 paraclinoid UIA (≤5 mm) were retrospectively evaluated during the mean follow-up of 32±17.3 months from September 2001 to May 2011. Barami’s classification was used for categorizing aneurysm location. Univariate and multivariate analyses were used to determine the risk factors of aneurysm growth. The Kaplan-Meier product-limit estimator and generalized Wilcoxon tests were performed to assess the cumulative survival without aneurysm growth. Results: None of the aneurysm ruptures and 12 (3.3%) cases of aneurysm growth were observed during the follow up of 969.7 aneurysm-years. Aneurysm ≥ 4mm (hazard ratio [HR], 6.73; p=0.001) and hypertension (HR, 4.92; p=0.02) were associated with aneurysm growth. Other variables including female (p=0.18), age (p=0.24), arterial branch related location (p=0.47), multiplicity (p=0.11), and smoking (p=0.36) did not differ significantly. The multivariate analysis disclosed that aneurysm ≥4mm (HR, 4.78; p=0.01) and hypertension (HR, 4.20; p=0.03) were significant predictable factors for aneurysm growth. The cumulative survival without aneurysm growth reached a significant difference in aneurysms ≥4mm (p Conclusions: Incidental small paraclinoid UIA can be primarily treated conservatively. Patients with high risk factors including aneurysm ≥4 mm and hypertension must be monitored closely.

BACKGROUND AND PURPOSE: Intravenous flat-detector CT (IV FDCT) angiography is an emerging technology for the detection of intracranial vascular disease. The study was conducted to determine the feasibility of IV FDCT in estimating major atherosclerotic intracranial arteries stenosis with digital subtraction angiography (DSA) as the reference. METHODS: DSA and IV FDCT were performed simultaneously in patients with transient ischemic attack or acute cerebral infarction. The degree and length of stenosis were measured. The stenotic vessels were categorized into four groups by the grade of stenosis: normal (70%). The vessels of the normal group were excluded from analysis to reduce spectrum bias. Measurement of vessels was recorded using an electric ruler by a qualified endovascular neurosurgeon and a neuroradiologist. RESULTS: A total of sixty-nine patients with 842 vessel segments were calculated. Mild (n=56), moderate (n=47) and severe stenosis (n=46) groups were analyzed. IV FDCT had a sensitivity of 97.6%, specificity of 96.9%, and a negative predictive value of 96.9% for detecting ≥50% stenosis and respective values of 91.9%, 98.2%, and 97.4 % for depicting ≥70% stenosis. The difference of stenotic length between two tests was not significantly difference as an increase in the severity of stenosis (Spearman’s rank test; r = - 0.12, p=0.13) CONCLUSION: IV FDCT can be a feasible alternative as a noninvasive method for evaluating stenosis of the major intracranial arteries.

Purpose: The purpose of this study was to assess the risk factors of prospective symptomatic hemorrhage in a large adult CM population. We also proposed a new predictive scoring scale for estimating the hemorrhage-free survival in patients with multiple risk factors. Materials and Methods: A total of 326 adult patients (over 18 years) with 410 CM were retrospectively evaluated during the mean follow-up of 31.4 months. Prospective symptomatic CM hemorrhage was defined as following: 1) a new clinical symptoms, and 2) radiographical hemorrhage including intra-or extralesional signal change or size increase>20%. A new CM classification was suggested: type I, typical mulberry appearance; type IIa, uniloculated CM in the hemisphere; type IIb, deep-seated uniloculated CM. Other risk factors, such as previous hemorrhage, the size and the location of CM, multiplicity and combined venous anomaly, were also evaluated using univariate and multivariate statistical analyses. Kaplan-Meier analysis was performed to assess the cumulative survival rate without symptomatic hemorrhage. Results: Prior symptomatic hemorrhage (p Conclusion: New predictive scoring system, including prior history of symptomatic hemorrhage and deep-seated CM without mulberry appearance, may be feasible for measuring the hemorrhage-free survival in adult CM patients with multiple risk factors.