Sidewall cerebral aneurysms: effect of an outflow angle-assisted approach on diagnosis.

BACKGROUND: The ability to diagnose sidewall cerebral aneurysms (SCAs) on an angle measurement basis may be useful in clinical practice. A study was undertaken to evaluate the effect of an outflow angle (OA)-assisted approach. METHODS: MR angiography (MRA) images of 438 patients with suspected SCAs and other cerebrovascular diseases were separately evaluated using the subjective approach and the OA approach. The approaches were then exchanged for confirmation of unclear cases. An OA of ≥90° was considered to represent SCA positivity. The accuracy, sensitivity, and specificity of the OA-assisted approach were determined using patient-based, aneurysm-based, and size-based evaluations. RESULTS: Digital subtraction angiography (DSA) detected 301 SCAs in 267 patients and no SCAs in 171. An OA of ≥90° was observed for 271 aneurysms in 244 patients (true positives); the OA approach misinterpreted OA as <90° for 29 aneurysms in 29 patients (false negatives) and missed one aneurysm. The subjective approach detected 309 SCAs in 273 patients. This approach misdiagnosed 10 patients (false positives) and missed two aneurysms in two patients (false negatives). The OA-assisted approach detected 300 SCAs in 267 patients and no SCAs in 171, overlooking one aneurysm. Patient-based evaluation yielded high accuracy, sensitivity, specificity, and positive and negative predictive values for the OA-assisted approach. CONCLUSIONS: The OA-assisted approach for SCA diagnosis effectively reduced the false-positive rate obtained with the subjective approach with high accuracy, sensitivity, and specificity, suggesting that MRA based on this approach can be a reliable alternative to DSA in SCA screening and diagnosis.

Aneurysm outflow angle at MRA as discriminant for accurate diagnosis and differentiation between small sidewall cerebral aneurysms and infundibula.

OBJECTIVE: To evaluate whether the aneurysm outflow angle (OA) at MR angiography (MRA) might serve as discriminant for accurate diagnosis of, and differentiation between, small sidewall cerebral aneurysms (SCAs) and infundibula. METHODS: Between June 2007 and July 2015, 426 consecutive patients with SCAs completed both an MRA and DSA examination. Of these, 156 patients with small SCAs and 52 patients with infundibula were included in this study. A patient with an OA ≥90° was defined as having a SCA, while those with OA <90° were defined as having an infundibulum. RESULTS: DSA identified 172 SCAs in 156 patients and 55 infundibula in 52 patients. The average OA on MRA was 102.96°±13.36° (range 60°-151°) in 172 SCAs of 156 patients. An OA of ≥90° was seen for 159 (92.4%) small SCAs in 147 patients, while an OA of <90° was observed for 13 SCAs. The average OA on MRA was 69.05°±14.26° (range 35-107°) in 55 infundibula of 52 patients. An OA of ≥90° was seen in one patient with one infundibulum; while an OA of <90° was observed for 54 infundibula (98.2%) in 51 patients. The average OA in SCAs (n=172) was greater than the average OA in infundibula (n=55; 102.96° vs 69.05°, p<0.001). CONCLUSIONS: The OA at MRA could serve as discriminant for accurate diagnosis of, and differentiation between, small SCAs and infundibula.

Reconstruction of the Internal Carotid Artery After Treatment of Complex Traumatic Direct Carotid-Cavernous Fistulas With the Willis Covered Stent: A Retrospective Study With Long-Term Follow-up.

BACKGROUND: Endovascular treatment of complex traumatic direct carotid-cavernous fistulas (TDCCFs) is a challenge. OBJECTIVE: To evaluate the long-term efficacy of the Willis covered stent in endovascular treatment of complex TDCCFs, focusing on reconstruction and preservation of the internal carotid artery. METHODS: During the past 8 years, 25 patients with 27 TDCCFs who previously had unsuccessful treatment of fistulas with detachable balloons received endovascular treatment with Willis covered stents. The efficacy, complications, in-stent stenosis, angiographic, and clinical follow-up results were evaluated retrospectively between 6 and 88 months (mean, 43.8 months) after the stent placement. RESULTS: The technical success rate of stenting placement was 100%. Forty-four Willis covered stents were implanted into the target artery of 27 TDCCFs. Complete exclusion was achieved in 16 patients with 17 TDCCFs immediately after the stent placement, with transient endoleaks in 10 TDCCFs. Redilation was performed in 6 TDCCFs, and additional stents were implanted in the other 4 TDCCFs for endoleak exclusion. The initial angiographic results showed complete exclusion of fistulas with preservation of the internal carotid artery in 24 patients with 26 TDCCFs. One patient in whom complete occlusion initially was achieved subsequently experienced a delayed endoleak, which required placement of an additional stent. The angiographic follow-up results (mean, 30.3 months) demonstrated complete exclusion in all 27 TDCCFs, with patency of internal carotid artery in 23 patients. The clinical follow-up demonstrated a full recovery in 23 patients and improvement in 2 patients. CONCLUSION: The use of Willis covered stents was confirmed to be effective, safe, and a curative approach for endovascular treatment of complex TDCCFs and internal carotid artery reconstruction. ABBREVIATIONS: DB, detachable balloonEVT, endovascular treatmentICA, internal carotid arteryn-BCA, N-butyl cyanoacrylateTDCCF, traumatic direct carotid-cavernous fistula.

Accurate diagnosis of small cerebral aneurysms ≤5 mm in diameter with 3.0-T MR angiography.

PURPOSE: To evaluate the diagnostic accuracy of three-dimensional (3D) time-of-flight (TOF) magnetic resonance (MR) angiography at 3.0 T in the detection of small cerebral aneurysms. MATERIALS AND METHODS: The institutional review board approved the study protocol, and patients or qualifying family members provided informed consent. A total of 403 consecutive patients undergoing 3D TOF MR angiography and digital subtraction angiography (DSA) were prospectively enrolled. Small aneurysms were those 5 mm in diameter or smaller. DSA served as the reference standard. Three observers were blinded to clinical and DSA results, and they independently analyzed all 3D TOF MR angiographic data sets. Interobserver agreement was expressed in terms of Cohen κ value for categorical variables. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 3D TOF MR angiography in the detection of cerebral aneurysms were determined by using patient-, aneurysm-, and location-based evaluations. RESULTS: Of 403 patients, 273 aneurysms were detected with DSA in 230 patients. Patient-based evaluation with 3D TOF MR angiography at 3.0 T yielded an accuracy of 96%-97%, a sensitivity of 98.2%-98.7%, a specificity of 93.2% -94.8%, a PPV of 94.9%-96.2%, and an NPV of 97.6%-98.2% in the detection of cerebral aneurysms. Aneurysm-based evaluation yielded an accuracy of 96.4%-97.3%, a sensitivity of 98.5%-98.9%, a specificity of 93.2%-94.9%, a PPV of 95.7%-96.8%, and an NPV of 97.6%-98.2%. Aneurysm-location evaluations yielded similar results. CONCLUSION: Three-dimensional TOF MR angiography is a noninvasive method that shows promising diagnostic accuracy in the detection of small cerebral aneurysms.

Treatment of a canine carotid artery aneurysm model with a biodegradable nanofiber-covered stent: a prospective pilot study.

AIM: To evaluate the use of a biodegradable nanofiber-covered stent (BDNCS) in the treatment of a canine carotid artery aneurysm. MATERIALS AND METHODS: Seventeen beagle dogs, each with one lateral saccular aneurysm created using a venous pouch, were selected to test the BDNCS. The BDNCS consists of three parts: A bare stent, a biodegradable nanofiber membrane, and a balloon catheter. The bare stent was sculpted by a laser from a cobalt chromium superalloy, and the biodegradable nanofiber membrane was constructed from polylactic acid (PLA) and polycaprolactone [PCL, P (LLA-CL)] by the electro-spinning method. The biodegradable nanofiber stent was premounted on a balloon catheter to form a BDNCS. Angiographic assessments were categorized as complete or incomplete occlusion. Data regarding technical success, initial and final angiographic results, mortality and morbidity were collected, and follow-up was performed at 1 and 3 months after the procedure. RESULTS: BDNCS placement was successful in 17 canines with 17 aneurysms. The initial angiographies showed that a complete occlusion was achieved in 13 canines (76.5%) and an incomplete occlusion in 4 (23.5%). One canine died 1 week later. The angiographies obtained at 3-month follow-up exhibited complete occlusion in 14 canines (87.5%) and an incomplete occlusion in 2 canines, with mild in-stent stenosis in 5 canines. CONCLUSIONS: Our results suggest that BDNCS may be a feasible approach for aneurysm occlusion, although the occurrence of mild in-stent stenosis was relatively high. Longer-term follow-up investigations are needed to validate these findings.

Differential diagnosis of infundibular dilation versus a small aneurysm of the internal carotid artery: assessment by three-dimensional rotational angiography with volume rendering.

We report our findings associated with the differential diagnosis of infundibular dilation (ID) versus a small intracranial aneurysm using three-dimensional rotational angiography with volume rendering (3DRA + VR). Angiographic findings associated with IDs found via two-dimensional digital subtraction angiography (2D-DSA) or 3DRA + VR were reviewed for 138 consecutive patients with known or suspected aneurysms. Two readers independently evaluated the results of 2D-DSA and 3DRA + VR according to the same diagnostic criteria. We also evaluated the ability of 3D-DSA to show the spatial relation between IDs and anterior choroidal (AchA)/posterior communicating (PcomA) arteries. 2D-DSA and 3DRA + VR found 41 and 48 IDs, respectively. 2D-DSA missed five AchA and two PcomA IDs. 2D-DSA was significantly inferior to 3DRA + VR for displaying the spatial relation between IDs and AchA/PcomA (P = 0). Thus, 3DRA + VR provides more useful information for distinguishing IDs from aneurysms. The superiority of 3DRA + VR might be because of its ability to display the spatial relation between IDs and AchA/PcomA.

Risk factors for multiple intracranial aneurysms rupture: a retrospective study.

BACKGROUND AND PURPOSE: The presence of predicting the rupture risk of intracranial aneurysms has recently generated considerable controversy. We retrospectively investigated the risk factors for multiple intracranial aneurysms related to rupture. METHODS: Between July 2007 and July 2011, 134 patients with 294 aneurysms were identified after review. Every patient had two or more aneurysms. Univariate and multivariate logistic regression models were used to analyze the risk factors for multiple intracranial aneurysms with age, gender, site and size. RESULTS: 134 patients were divided into three groups according to patient age category (<45, 45-65, >65 years of age). The incidence of aneurysms ruptured in the second group was significantly higher. Three groups showed significant difference (P=0.001 versus >65 years of age). Thirteen of 35 AComA aneurysms were ruptured, accounting for 26% of all ruptured aneurysms, and the rate of rupture at AComA aneurysms in patients was 37.1%. The rate of aneurysm rupture in the AComA was significantly higher than that in other sites (P=0.001). In all 294 aneurysms, 88.1% of the aneurysms were 5mm or less, of which 58.2% were less than 3mm. In the ruptured aneurysms, 68% were 5mm or less. CONCLUSIONS: Our study reveals the pattern of ruptured multiple intracranial aneurysms, in terms of age, size and location of aneurysms. Age, size, and site of aneurysm should be considered in the decision whether to treat an unruptured aneurysm or not. Especially, in cases of multiple aneurysm, the AComA aneurysm is most prone to hemorrhage.

Evaluation of intracranial aneurysms with high-resolution MR angiography using single-artery highlighting technique: correlation with digital subtraction angiography.

PURPOSE: The authors investigated the effectiveness of high-resolution magnetic resonance angiography (MRA) using a single-artery highlighting technique for the accurate diagnosis of intracranial aneurysms at 3.0 T in a large cohort of patients with suspected intracranial aneurysms against the current gold standard, i.e. cerebral angiography. METHODS: A total of 307 patients with suspected aneurysms were referred for three-dimensional time-of-flight MRA (3D-TOF-MRA) prior to digital subtraction angiography (DSA). We summarised patient-based, aneurysm-based and vessel-based diagnostic performance parameters, namely, accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detecting intracranial aneurysms with 3D-TOF-MRA. Interobserver agreement was calculated with the kappa (κ) statistic. RESULTS: Patient-based accuracy was 98.1%, sensitivity 99.5%, specificity 95.3%, PPV 97.6% and NPV 99% according to observer A; and 97.7%, 99.5%, 94.3%, 97.1% and 99%, respectively, according to observer B. Aneurysmbased accuracy was 98.3%, sensitivity 99.6%, specificity 95.2%, PPV 98.1% and NPV 99% according to observer A, and 98.0%, 99.6%, 94.3%, 97.7% and 99%, respectively, according to observer B. Vessel-based accuracy was 99.0%, sensitivity 99.6%, specificity 98.7%, PPV 97.8%, and NPV 99.7% according to observer A, and 98.9%, 99.6%, 98.5%, 97.3%, and 99.7%, respectively, according to observer B. Interobserver reading differences were not significant. The interobserver agreement was good, with a kappa (κ) value of 0.931 for patient-based evaluation, 0.934 for aneurysmbased evaluation and 0.953 for vessel-based evaluation. CONCLUSIONS: Our results demonstrate the effectiveness of high-resolution MRA using a single-artery-highlighting technique for accurate diagnosis of intracranial aneurysms in a large cohort of patients with suspected aneurysms.

Frequency and predictors of endoleaks and long-term patency after covered stent placement for the treatment of intracranial aneurysms: a prospective, non-randomised multicentre experience.

OBJECTIVE: We investigated immediate/late endoleaks and long-term patency following stent-graft placement for treatment of intracranial aneurysms located within the distal internal carotid artery (ICA) or vertebral artery (VA). METHODS: Forty-five aneurysms in 41 patients receiving covered stents in three centres were followed. Outcome measures included aneurysm occlusion rate, endoleaks, late in-stent stenosis rate, clinical improvement, neurological deficiencies and death. RESULTS: Total aneurysm exclusion was achieved in 69.2% (n = 27), with 30.8% (n = 12) experiencing immediate residual endoleaks. Angiographic follow-up (mean 43.5 ± 14.3 months) revealed that 87.2% (n = 34) were completely occluded with only 12.8% (n = 5) showing residual endoleaks. Predictors of immediate endoleaks in our patient group were stent number (P = 0.023) and stent diameter (P = 0.022), while predictors of late endoleaks in our patient group were stent diameter (P = 0.035) and stent angulation (P = 0.021). Late in-stent stenosis rates were 18.0 ± 13.3 and 29.0 ± 18.5% compared with the period immediately following implantation at 2- and 6-year follow-ups respectively. Smoking (P = 0.017) and stent angulation (P = 0.020) were predictors of late in-stent stenosis. CONCLUSION: Treating intracranial aneurysms with Willis stent-grafts has an acceptable immediate and late occlusion rate and long-term stented artery patency rate.

The clinical value of MRA at 3.0 T for the diagnosis and therapeutic planning of patients with subarachnoid haemorrhage.

OBJECTIVE: To evaluate the clinical value of unenhanced magnetic resonance angiography (MRA) at 3.0 T for the diagnosis and therapeutic planning of patients with subarachnoid haemorrhage (SAH). METHODS: A total of 165 patients with SAH were referred for three-dimensional time-of-flight MRA (3D-TOF-MRA) before digital subtraction angiography (DSA). For each aneurysm, 3D-TOF-MRA was used to determine whether the aneurysm was suitable for coil placement with or without balloon/stent-assisted coiling, surgical clipping or conservative treatment. Treatment planning with 3D-TOF-MRA was compared with actual treatment decisions or treatment that had been carried out in each aneurysm decided using DSA. RESULTS: The aneurysm-based evaluation yielded accuracy of 96.9%, sensitivity of 97.6%, specificity of 93.1%, positive predictive value (PPV) of 98.8% and negative predictive value (NPV) of 87.1%, in the detection of intracranial aneurysms. Treatment planning could be correctly made on the basis of aneurysm anatomy and working view by volume rendering (VR) 3D-TOF-MRA with accuracy, sensitivity, specificity, PPV and NPV of 94.9%, 94.0%, 100%, 100% and 74.4%, respectively, on a per aneurysm-based evaluation. CONCLUSIONS: VR 3D-TOF-MRA offers high diagnostic accuracy in the detection of ruptured intracranial aneurysms, and appears to be an effective treatment planning tool for most patients with SAH. KEY POINTS: VR 3D-TOF-MRA offers high diagnostic accuracy for detecting ruptured intracranial aneurysms. • VR 3D-TOF-MRA helps treatment planning for patients with subarachnoid haemorrhage. • 3D-TOF-MRA is non-invasive and avoids using ionising radiation or contrast agents.

Treatment of traumatic internal carotid artery pseudoaneurysms with the Willis covered stent: a prospective study.

PURPOSE: To evaluate the efficacy of the Willis covered stent in the treatment of traumatic pseudoaneurysms of the internal carotid artery (ICA). MATERIALS: Thirty-eight patients with traumatic head and neck injury underwent angiography. We evaluated 14 delayed pseudoaneurysms in 13 patients who underwent angiography after treatment with the Willis covered stent. Prospective data on the technical success, initial and final angiographic results, mortality, morbidity, and final clinical outcome were analyzed immediately after the procedure, at the time of discharge from the hospital, at 3 months, 6 months, and 12 months after the procedures, and yearly thereafter. RESULTS: The Willis covered stent placement was successful in all 14 pseudoaneurysms. The initial angiographic results showed complete exclusion in 9 patients with 10 aneurysms (71.4% [95% confidence interval {CI}: 44-98%]) and incomplete exclusion in 4 patients. The angiographic follow-up (mean, 15 months [95% CI: 9-20 months]; range, 3-36 months) findings exhibited a complete exclusion in 12 patients with 13 aneurysms (92.9% [95% CI: 77-108%]) and an incomplete exclusion in 1 patient and maintained patency of the ICA in all patients. The clinical follow-up (mean, 20 months [95% CI: 14-27 months]) findings demonstrated full recovery (11 patients), symptom improvement (1 patient), or no change in the symptoms (1 patient). No procedure-related complications or deaths occurred during follow-up. CONCLUSION: Treatment with the Willis covered stent provides a viable approach for patients with traumatic pseudoaneurysms of the ICA, maintaining patency of the ICA and thus leading to excellent clinical results. An expanded clinical experiences and a larger sample are needed.

Endovascular treatment of post-traumatic direct carotid-cavernous fistulas: A single-center experience.

We report our single-center experience using detachable balloons (DB), coils and Willis covered stents (MicroPort, Shanghai, China) to treat post-traumatic direct carotid-cavernous fistulas (DCCFs), focusing on preservation of the internal carotid artery (ICA). We retrospectively reviewed the records of 51 patients who received endovascular treatment (EVT). EVT with DBs was chosen as the first-line therapeutic strategy, and Willis covered stent placement and coiling was the alternative. The patency and stability of all DCCFs was evaluated by angiographic and clinical follow-up for between 3 and 48 months. A total of 54 DCCFs in 51 patients were treated as follows: DB alone (n=40); combined DB and Willis covered stent (n=8); Willis covered stent alone (n=2); combined DB and coils (n=2); coils alone (n=1); and DB in combination with both coils and a Willis covered stent (n=1). Overall, 98% of DCCFs were successfully treated with the occlusion of the fistula and preservation of the ICA; the ICA was sacrificed in only one patient. Approximately 85% of DCCFs were successfully treated with DBs alone. Second and third administrations of EVT were required in 12 DCCFs. DCCF-related symptoms improved gradually between 1 day and 6 months after treatment. EVT using DB to occlude fistulas and preserve the ICA is the preferential treatment for DCCFs. When standard treatment has failed, coils and/or Willis covered stents can be used as a safe alternative or remedial tool with ICA preservation and reconstruction.

Infundibular dilation: an anatomical variant or a pre-aneurysm? Advantages of assessment with three-dimensional rotational angiography.

PURPOSE: Whether an infundibular dilation (ID) is an anatomical variant or a pre-aneurysm has not been clearly determined. The aim of the present study was to evaluate the anatomical change of IDs by use of three-dimensional rotational angiography (3DRA) with volume rendering (VR). METHODS: One-hundred thirty-eight patients with known or suspected aneurysms, treated consecutively, underwent both two-dimensional digital subtraction angiography (2DDSA) and 3DRA with VR. Two readers evaluated the IDs or aneurysms blindly, using 2DDSA and 3DRA, according to the same diagnostic criteria. A 5-point scale of observer confidence was used to determine the presence of IDs or aneurysms. For 3DRA with VR, the relationship between IDs and aneurysms was classified as one of the three types: type I, protrusion or bulge from side wall of IDs; type II, aneurysms involving or enclosing IDs; or type III, aneurysms and IDs coexisting near each other but with some distance between them. RESULTS: The number of IDs found by 2DDSA and 3DRA with VR was 41 and 48, respectively. Five anterior choroidal arteries and two posterior communicating arteries IDs were missed by 2DDSA. According to 3DRA with VR, there were five IDs of type I, nine of type II, and 22 of type III. CONCLUSIONS: The 3DRA with VR appears superior to 2DRA for both diagnosing IDs and displaying the anatomical relationship between IDs and aneurysms. The findings also suggest that some IDs might progress to aneurysms or become a part of them, which should be carefully evaluated prior to operation.

3D rotational angiography with volume rendering: the utility in the detection of intracranial aneurysms.

AIMS: The advent of three-dimensional (3D) rotational angiography (3D DSA) challenged the role of digital subtraction angiography (DSA) as a "gold standard" in the diagnosis of intracranial aneurysms. In this study, we report our experiences in diagnosing intracranial aneurysms by using 3D DSA with volume rendering (VR) technique, particularly focusing on its role in depicting additional aneurysms missed by 2D DSA. MATERIALS AND METHODS: One hundred and thirty-eight consecutive patients with known or suspected aneurysms (54 men, 84 women; median age, 55 years; age range, 18-83 years) underwent both conventional DSA and 3D DSA with VR examination simultaneously. The images of 2D DSA or 3D DSA with VR were evaluated by two observers independently for the presence of aneurysms. Then additional aneurysms were decided and depicted. RESULTS: 3D DSA with VR showed 146 aneurysms in 123 (89.1%) of 138 patients and no aneurysms in 15 patients. 2D DSA showed 115 aneurysms in 110 of 137 patients, with one aneurysm in 106 patients each, 2 in 3 patients each and 3 in 1 patient. After reaching a consensus, there were 31 additional aneurysms detected by 3D DSA with VR. 30 aneurysms were <3 mm in maximum diameter with 3 aneurysms ruptured. These additional aneurysms were located in internal carotid artery (ICA, n = 28, 90.32%), anterior cerebral artery (ACA, n = 3, 9.68%). No additional aneurysms were found in either middle cerebral artery (MCA) or vertebrobasilar and posterior cerebral artery (PCA) systems. CONCLUSIONS: 3D DSA, especially VR images, not only clearly reveals aneurysms and aneurysmal morphology, but also detects additional aneurysms missed by 2D DSA, especially small aneurysms less than 3 mm.

Safety, feasibility, and mid-term follow-up of Willis stent graft placement in the treatment of symptomatic complicated intra- or extra-cranial aneurysms: a multicenter experience.

We report the technical success rate and mid-term follow-up results after deploying stent-grafts to treat a cohort of patients with symptomatic complicated intra- or extracranial aneurysms (SCIEAs). This study was a retrospective review of 58 patients (39 male; mean age 40.4 ± 12.3 years) with 60 SCIEAs treated by 67 Willis covered stents at three medical centers in China between April 2005 and January 2010. The locations of the SCIEAs were as follows: Intracranial internal carotid artery (ICA) in 54 patients, extracranial ICA in one, intracranial vertebral artery (VA) in three and extra-cranial VA in two. Surgery was successful in 59 (98.3%) SCIEAs. Total exclusion was immediately achieved in 48 SCIEAs, and minor endoleaks were present in 11. Acute thrombosis occurred in two patients and hemorrhage in one. Follow-up angiography (mean 13.8 ± 8.9 months) revealed that 49 of 52 (94.2%) aneurysms were completely isolated, with mild in-stent stenosis in only two patients and in-stent occlusion in one patient. Willis stent-graft application is an alternative therapy to treat SCIEAs in either intra- or extracranial ICAs or VAs. In the case of a tortuous intracranial ICA or potential side branch coverage, however, it is still not a first choice.

Establishment of a novel hemodynamic cerebral ischemia model of atherosclerotic rabbit.

BACKGROUND: Atherosclerosis is the most common cause of ischemic stroke. Until now, there has been no ideal animal model for studying the hemodynamic ischemia caused by atherosclerosis in posterior circulation. OBJECTIVE: This study was conducted to establish a cerebral ischemic model in an atherosclerotic rabbit by subclavian artery (SA) ligation or embolization, emphasizing the role of hemodynamics. MATERIALS AND METHODS: Thirty-two male New Zealand rabbits (weight, 3.5 to 4.0 kg; provided by Animal Laboratory of Tongji Hospital of Tongji University) were randomly divided into four groups. All the groups, except the controlled group, were fed with high lipid diet for three months and two of the groups were submitted for right SA ligation or left SA embolization and the remaining one group to non-operated group. RESULTS: A SA steal syndrome was established successfully with delayed visualization and prolonged circulation time in the posterior circulation. The circulation time was different when SA was ligated or embolized (P < 0.001), and also there was statistically significant difference between controlled and non-operated groups when angiography of either, left and right, VA was performed (P = 0.009, P = 0.003, respectively). However, there was no statistical significant difference between the ligation and embolization group either before or after the procedure (ligation or embolization) (P = 0.402, P = 0.068, respectively). In the control and non-operated group, angiography of either left or right VA showed no statistically significant difference (P = 0.285, P = 0.197, respectively). In the groups fed with high lipid diet for three months, atherosclerotic plaques were found in the common carotid arteries (CCAs), aortic arch (AAs) and variably in the internal carotid arteries (ICAs). CONCLUSIONS: This model could, to some extent, simulate the clinical hemodynamic state of atherosclerotic stroke. and it is an ideal model for studying the hemodynamic cerebral ischemia in posterior circulation.

[Treatment of dural arteriovenous fistula by transarterial embolization with low dose of N-butyl-2-cyanoacrylate].

OBJECTIVE: To evaluate the efficacy of treatment of dural arteriovenous fistula (DAVF) by transarterial embolization with low dose of N-butyl-2-cyanoacrylate (NBCA). METHODS: Eighteen patients, 6 males and 12 females, aged 47.5 (23-72), with DAVF, 12 with carotid cavernous fistula and 6 with fistula in parietal lobe, underwent transarterial embolization with low dose of NBCA (10%-20%). The key point of transarterial embolization with low dose of NBCA was that low dose NBCA was injected and embolized the veins and then was reversed into the other supplying arteries. RESULTS: Seventeen patients with DAVF in cavernous region and 6 patients with DAVF in parietal lobe were cured anatomically, with the clinical syndromes disappearing. In 1 patient with DAVF in cavernous region the clinical syndrome were moderately improved after transarterial embolization, however, worsened 2 days later. Cerebrovascular angiography demonstrated that the vein was not completely embolized and the draining vein was broadened, and the clinical syndromes were moderately improved again after carotid artery compression therapy for 10 days. CONCLUSION: Convenient and fast, and with low cost and satisfying efficacy, transarterial embolization with low dose of NBCA is a better choice for treatment of DAVF in some cases. The key point of this approach is that the tip of microcatheter is close as much as possible to the fistulae, and NBCA is injected into the fistulae and make the vein diffused well. Attention should be paid to avoid dangerous anastomosis.