Rate of vasospasm following the transsylvian versus transcortical approach for selective amygdalohippocampectomy

Affection of the cerebral circulation following the extraaxial transsylvian approach has been reported. This study aims at the comparison of the risk for the development of vasospasm in the transparenchymal transcortical versus the transsylvian approach for selective amygdalohippocampectomy in patients with Ammon's horn sclerosis. n = 80 consecutive patients (13-58 years) were randomized and allotted to either the transsylvian (TS) or transcortical (TC) group. Bilateral middle cerebral arteries (MCA) and internal carotid arteries (ICA) were examined with transcranial Doppler pre-operatively, and from post-operative day 1 to 7. Blood flow velocities (BFV) were compared via ANOVA. Post-operatively, ipsilateral (= side of operative approach) mean BFV increased significantly in both groups with a mean ipsilateral increase of 79.2% in the TS group, and 48.8% in the TC group. This intergroup difference was also statistically significant. In addition, contralateral BFV increased significantly to a maximum mean of 26.3% in the TS group with no significant increase in the TC group. The results in the TS group are interpreted as vasospasm and not hyperemia - due to dissection of the sylvian vessels and the breakdown of blood within the basal cisterns. Factors such as the extent of visual field cuts and results from neuropsychological testing must be taken into account before drawing a conclusion leading to a fundamental change in surgical strategy.     

Experience with intraoperative high frequency Doppler sonography in neurosurgical practice

Abstract

The method of blood flow velocity (BFV) evaluation by intraoperative application of the high frequency Doppler is presented. The device is used to estimate BFV changes in small caliber arteries by direct placement of the probe upon the examined vessel. BFVexaminations were performed on the site during aneurysm operations, during transsphenoidal approaches to identify the intracavernous portion of leA embedded in the tumor mass and in patients after encephalodurosynangiosis evaluated on the outpatient basis. Technical characteristics of the flowmeter used are described and examples of the BFV pictures in cerebral arteries are presented. The device allows a precise BFVevaluation in the selected vessel and detection of changes in BFV patterns particularly useful during aneurysms surgery. This method of identifying cerebral vessels may become applicable in other types of neurosurgical operations. [Neural Res 1998; 20: 655–657]     

Cerebral blood flow reactivity in patients undergoing selective amygdalohippocampectomy for epilepsy of mesial temporal origin. A prospective randomized comparison of the trans-Sylvian and the transcortical approach

Objective: The aim of this study was to assess (1) whether vasoreactivity is altered in patients with epilepsy and (2) whether the two most commonly used approaches, the trans-Sylvian (TS) and the trans-cortical (TC) route, differ in their impact on cortical blood flow.

Methods: Patients were randomized to undergo selective amygdalohippocampectomy (selAH) through a TC or TS route. Before and after selAH, we recorded microcirculation parameters on the superficial cortex surrounding the surgical corridor. Blood flow and velocity were measured using laser Doppler flowmetry and micro-Doppler, respectively. Cortical oxygen saturation (SO₂) was measured using remission spectrophotometry under hypocapnic and normocapnic conditions.

Results: Ten patients were operated using the TS approach, and eight were operated via the TC approach. Vasomotor reactivity patterns measured with micro-Doppler were physiologically prior to selAH in both groups. After completion of surgery, a significant increase in SO₂-values occurred in the TS group (before: 56.7 ± 2.2, after: 65.5 ± 3.0%SO₂), but not in the TC group (before: 52.9 ± 5.2, after: 53.0 ± 3.7%SO₂). The rate of critical SO₂ values below 25% was significantly higher after the TC approach (12.3%) compared to the TS approach (5.2%; p < 0.05).

Discussion: Our findings provide the first invasively measured evidence that patients with mesial temporal lobe epilepsy have preserved cerebral blood flow responses to alterations in CO₂. In addition, local cortical SO₂ was higher in the TS group than in the TC group after selAH. This may be a sign of reactive cortical vessel dilation after proximal vessel manipulation associated with the TS approach. In contrast, the lower values of SO₂ after the TC approach indicate tissue ischaemia surrounding the surgical corridor surrounding the corticotomy.     

Impact of intracranial blood-flow redistribution on stroke size during ischemia-reperfusion in 7-day-old rats

We evaluated color-coded pulsed Doppler ultrasound imaging for the assessment of intracranial blood flow in two models of cerebral ischemia in 7-day-old (P7) rats. Blood-flow velocities (BFVs) were measured in the internal carotid arteries and basilar trunk upstream from the circle of Willis, and in the posterior cerebral arteries downstream (1) before, (2) during left middle cerebral artery electrocoagulation and 50 min-transient either one (I/R-1) or both (I/R-2) common carotid (CCA) arteries occlusion, and (3) after release of CCA(s) occlusion. At 48 h after ischemia 41-48% (I/R-1 model) and 24% (I/R-2 model) of rats did not present a lesion. Those rats displayed increased mean BFV in both right internal carotid artery and basilar trunk in I/R-1 model, and increased mean BFV in the basilar trunk (BT) in I/R-2 model. In contrast, no significant changes in mean BFV were observed in lesioned rats. Furthermore, mean BFV in the BT was inversely correlated to the size of the lesion (r2 = 0.75, p<0.0001) in the I/R-2 model. Thus, we demonstrated the protective role of collateral support in P7 rodents. Ultrasound imaging can evidence the establishment or not of the cerebral collateral recruitment, leading to the presence or absence of a lesion. This novel approach should greatly help preclinical studies to reduce animal variability.     

Role of Ca2+-dependent K+ channels in erythrocyte lysate-induced contraction of rabbit cerebral artery

Abstract

K⁺ channel openers may be useful in the treatment of cerebral vasospasm following subarachnoid hemorrhage. However, the role of Ca²⁺ -dependent K⁺ channel (KCa) openers in cerebral vasospasm remain unclear. This study was undertaken to examine the role ofKCa in hemolysate-induced contraction of rabbit cerebral and peripheral arteries: 7. Iberiotoxin (IBX), a selective KCa channel blocker, produced more pronounced contraction in basilar than in those of carotid or femoral arteries, indicating KCa channels are important regulating factors in cerebral arteries; 2. NS1619, a selective KCa channel opener, abolished the contraction of basilar artery to erythrocyte lysate, a causative agent for cerebral vasospasm; 3. In rabbit basilar artery, NS1619 relaxed the contractions to IBX, erythrocyte lysate and KCI (20 and 60 mM), indicating that NS1619, besides opening KCa channels, possesses other vasodilating actions. We conclude that KCa channels are important factors in the regulation of cerebral vascular tension and KCa channel opener NS1619 may have dual relaxant actions in cerebral arteries. [Neurol Res 1999; 21: 705–711 ]     

Cilostazol attenuates cerebral vasospasm after experimental subarachnoid hemorrhage

Abstract

Background and purpose: Cerebral vasospasm is a major cause of morbidity and mortality in patients with subarachnoid hemorrhage (SAH). Cilostazol, a selective inhibitor of phosphodiesterase 3, is a peripheral vasodilator, an anti-inflammatory, and causes antiplatelet aggregation. We investigated these effects on cerebral vasospasm after rat SAH.

Methods: Thirty-eight Sprague–Dawley rats were randomly divided into three groups: SAH + normal feed (SAH group; n=14), SAH + feed containing 0·1% cilostazol (cilostazol group; n=12) and sham-operated rats (sham group; n=12). The basilar arteries (BA) of all groups were analysed by measuring wall thickness, internal luminal perimeter and cross-sectional area on day 7. Immunohistochemical study with RM-4, an anti-rat macrophage/dendritic cells monoclonal antibody and ultrastructural study with transmission electron microscopy were performed.

Results: Although most animals in the SAH group presented with typical vasospasm, the means of inner perimeter and cross-section area of the BA in the cilostazol group were significantly greater than the SAH group (836 ± 134 μm versus 771 ± 125 μm and 39177 ± 15405 μm² versus 33098 ± 13871 μm², respectively). Wall thickness of the BA in the cilostazol group demonstrated significant decrease, compared with the SAH group (17·4 ± 2·3 versus 21·0 ± 2·7 μm). In immunohistological study, SAH induced an obvious increase in mean perivascular RM-4-positive cell count, whereas cilostazol significantly reduced it by 59%. Ultrastructural study depicted cilostazol markedly attenuating structural deterioration of the vascular wall due to SAH.

Conclusions: This work demonstrates that cilostazol attenuates cerebral vasospasm after SAH in rat, possibly in part due to the anti-inflammatory effect.     

二维相位对比磁共振血管成像测量脑血流量：颈动脉及其同侧分支血流量的验证

课题组前期研究证实,相位对比磁共振血管成像测量脑血流量的最佳速度编码为60～80cm/s。为验证二维相位对比磁共振血管成像测量脑血流量的准确性,实验以三维时间飞越法磁共振血管成像定位颈部血管感兴趣区,设定速度编码为80cm/s,对10名健康志愿者的20组颈总动脉、颈内动脉和颈外动脉的血流量测量结果显示,颈总动脉与其分支颈内动脉和颈外动脉血流量之和误差为（7.0±6.0）%,二者比较差异无显著性意义,且具有明显的相关性,同时颈总动脉血流量也与同侧颈内动脉血流量相关。造成误差的主要原因来自于颈外动脉及其分支。合理运用扫描参数及方案,二维相位对比磁共振血管成像可准确测量脑血流量。     

Detection of cerebral artery fenestrations by computed tomography angiography

Background and purposeCerebral artery fenestrations (CAF) are rare congenital variations usually diagnosed by digital subtraction angiography (DSA). The aim of this study was to examine the frequency of occurrence of fenestrations in cerebral arteries and their coexistence with cerebral aneurysms in computed tomography angiography (CTA).Material and methodsAll reports of cerebral CTA (1140) performed in one institution from March 2005 to December 2007 were analysed. We found 40 patients with single fenestrations of the intracranial arteries. All 40 examinations were retrospectively reviewed for location of vascular malformations and presence of aneurysms or subarachnoid haemorrhage (SAH). Medical histories of those patients were then analysed for evidence of SAH and referral reasons for CTA.ResultsForty fenestrated arteries were found in CTA: 18 basilar arteries (45%), 16 anterior cerebral arteries (40%), 4 anterior communicating arteries (10%) and one middle cerebral artery (2.5%). Only one vertebral artery fenestration was found due to the technique of the examination. Six patients (15%) with fenestrated arteries had a total of 8 aneurysms, although only one aneurysm was ipsilateral to the fenestration. In 8 cases of SAH, two were with no evidence of vascular malformation. The coexistence of CAF and aneurysms in CTA amounted to 15% (6/40), but the incidence of ipsilateral aneurysm was only 2.5% (1/40) and it affected the anterior cerebral artery.ConclusionsBasilar artery fenestration is the most frequent observed fenestration in CTA, followed by anterior cerebral artery and anterior communicating artery fenestrations. Coexistence of fenestration and aneurysm is uncommon in CTA examination.     

Comparison of transcranial Doppler ultrasonography and positron emission tomography using a three-dimensional template of the middle cerebral artery

Abstract

Objective: Transcranial Doppler (TCD) measures blood flow velocities (BFV) and is an indirect method of assessing cerebral blood flow (CBF). Positron emission tomography (PET) is a direct method to measure CBF. This study evaluates the correlations between TCD and PET findings

Methods: Nine patients with a symptomatic carotid artery stenosis, who underwent CEA, were studied pre- and post-operatively on the ipsi- and contralateral sides. Measurements of the BFV, CO₂ reactivity, CBF, cerebral blood volume (CBV) and mean vascular transit time (MVTT) were performed using a three-dimensional volume of interest (VOI) for the middle cerebral artery (MCA).

Results: CBF in the MCA region, as measured with PET, shows a good correlation with BFV, as measured with TCD, with similar pattern for total, gray and white matter MCA territory (Pearson's correlation coefficients: 0.751, 0.748 and 0.748, respectively). This correlation was found in the pre-operative as well as the post-operative state. No association could be demonstrated between CO₂ reactivity and CBV or (Pearson's correlation coefficients: 0.051 and 0.166, respectively).

Conclusion: With PET, it is possible to create three-dimensional VOI of arterial territories. CBF measured in these VOI seems to correlate with BFV before and after CEA on ipsi- and contralateral sides, while CBV shows no association with pre-operative CO₂ reactivity.     

Accuracy of transcranial colour-coded sonography in the diagnosis of anterior cerebral artery vasospasm

Background and purposeTranscranial colour-coded sonography (TCCS) has been proven to be a method of high performance in the diagnosis of spasm of the middle cerebral artery (MCA). Relevant data concerning the anterior cerebral artery (ACA) varies amongst studies. The aim of this study was to assess the performance of TCCS in the diagnosis of spasm affecting the ACA.Material and methodsNinety-two patients (39 women and 53 men, age 51 ± 12.1 years) were examined using TCCS before cerebral angiography. Of 184 examined ACAs, only 133 arteries could be visualized due to insufficiency of the temporal acoustic window. Therefore, only 15 out of 25 arteries in which vasospasm was diagnosed with angiography (by two neuroradiologists not informed about the sonographic findings) could be included in the analysis. Receiver operating characteristic (ROC) curves were constructed for specific blood flow velocities: peak systolic (PSV), mean (M) and end-diastolic (EDV). The area under the ROC curve was used to measure the overall diagnostic performance of TCCS.ResultsThe area under the ROC curve for PSV was 0.83, which indicates good performance. The PSV threshold of 98 cm/s corresponded to maximum accuracy and was associated with 71% sensitivity vs. 88% specificity. Average systolic blood flow velocity in the vessels with vasospasm was 129 cm/s, whereas in unaffected vessels it was 76 cm/s.ConclusionsThe accuracy of TCCS in the diagnosis of ACA spasm is relatively high – the value of the area under the ROC amounts to 0.83. PSV performs best and the threshold of 98 cm/s is associated with an optimal trade-off between sensitivity and specificity.     

The Effectiveness of Lumbar Cerebrospinal Fluid Drainage to Reduce the Cerebral Vasospasm after Surgical Clipping for Aneurysmal Subarachnoid Hemorrhage

ObjectiveRemoval of blood from subarachnoid space with a lumbar drainage (LD) may decrease development of cerebral vasospasm. We evaluated the effectiveness of a LD for a clinical vasospasm and outcomes after clipping of aneurysmal subarachnoid hemorrhage (SAH).MethodsBetween July 2008 and July 2013, 234 patients were included in this study. The LD group consisted of 126 patients, 108 patients in the non LD group. We investigated outcomes as follow : 1) clinical vasospasm, 2) angioplasty, 3) cerebral infarction, 4) Glasgow outcome scale (GOS) score at discharge, 5) GOS score at 6-month follow-up, and 6) mortality.ResultsClinical vasospasm occurred in 19% of the LD group and 42% of the non LD group (p<0.001). Angioplasty was performed in 17% of the LD group and 38% of the non LD group (p=0.001). Cerebral infarctions were detected in 29% and 54% of each group respectively (p<0.001). The proportion of GOS score 5 at 6 month follow-up in the LD group was 69%, and it was 58% in the non LD group (p=0.001). Mortality rate showed 5% and 10% in each group respectively. But, there was no difference in shunt between the two groups.ConclusionLD after aneurysmal SAH shows marked reduction of clinical vasospasm and need for angioplasty. With this technique we have shown favorable GOS score at 6 month follow-up.     

Neuropsychological outcome after selective amygdalohippocampectomy with transsylvian versus transcortical approach: a randomized prospective clinical trial of surgery for temporal lobe epilepsy

PURPOSE: Selective amygdalohippocampectomy (SAH) is a surgical treatment option for patients with medically intractable mesial temporal lobe epilepsy. In contrast to standard anterior temporal lobectomy, resection of unaffected tissue is limited, although it achieves equal seizure outcomes in selected patients. In SAH, the mesial structures can be approached by different routes, the transsylvian approach and the transcortical approach. Advantages or disadvantages with respect to postoperative cognitive outcome are still a matter of debate. METHODS: Eighty randomized patients were included in the analyses. In 41 patients, the transsylvian approach, and in 39 patients, the transcortical approach was performed. All patients received comprehensive neuropsychological testing of verbal and nonverbal memory, attention, and executive functions before and 6 months or 1 year after SAH. RESULTS: Seventy-five percent of patients became completely seizure free with no difference depending on the chosen approach. Repeated measures multivariate analysis of variance (MANOVA) showed that cognitive outcomes after both approaches were essentially the same. The only exception was phonemic fluency, which was significantly improved after transcortical but not after transsylvian SAH. CONCLUSIONS: The results indicate that either surgical approach can be chosen independent of cognitive outcome criteria. Improvement in phonemic fluency after transcortical SAH may reflect selective normalization of cognitive function after epilepsy surgery, whereas frontal lobe manipulation might have hindered recovery of this function after transsylvian SAH.     

Doppler ultrasonographic measurement of blood flow velocities in major cerebral arteries of the rat using triplex mode

Abstract

Objective: In patients with subarachnoid hemorrhage, delayed cerebral ischemia caused by vasospasm of major cerebral arteries is an important factor of morbidity. While Doppler ultrasonographic monitoring of blood flow velocities is a routine bedside examination in these patients, the current rodent models of vasospasm do not include this technique. In this article, we present an extended craniectomy in rats, which allows for direct angle-corrected Doppler ultrasonographic examination of major cerebral vessels.

Methods: Ultrasonographic examination employs a triplex window displaying simultaneously B-mode, colour coded vessel rendering and Doppler-assessment of blood flow velocity. The animals receive anesthesia for the measurements, which are repeated several times a week.

Results: Mean flow velocities determined by 116 measurements in 16 animals are (cm/s): truncus cerebri anterius: 8.16, arteria pericallosa: 7.49, arteries (Aa.) cerebri anteriores: 7.76, Aa. carotides: 8.76, Aa. cerebri mediae: 8.55, Aa. cerebri posteriores: 5.27, artery (A.) basilaris: 5.90.

Discussion: We describe the direct intravital detection of blood flow velocities in major cerebral vessels of the rat. The technique allows for simultaneous visualization of intracranial structures, vessel diameters and cerebral blood flow velocities. Our ongoing research focuses on determining normal values in a larger population of animals and examining the feasibility of the technique regarding the rodent model of vasospasm.     

Protection by lloprost (stable analogue of prostacyclin) of endothelial damage due to chronic vasospasm in dogs: An electron microscope study

Abstract

The resolution of cerebral vasospasm and protection of endothelial damage by lloprost was evaluated with multicisternal injections. Sixteen adult mongrel dogs (18-20 kg) were assigned to one of three experimental groups. All animals received a total amount of 15 ml fresh unheparinized arterial blood via three injections into the cisterna magna. Selective vertebral angiography was performed on day 0 and subsequently blood injections were performed on the 2nd and 3rd days after the first injection. On the 7th day angiography was reperformed to determine the chronic vasospasm. The first group (5 dogs) was the control group and received intrathecal saline which was equal to the amount of saline in which lloprost was diluted. The second group (5 dogs) did not receive any treatment until the 7th day. The third group (6 dogs) received lloprost intrathecally (total 10 fig kg~1). In the first two groups angiographic vasospasm was prominent. For the second group intraarterial lloprost was given on the 7th day in order to evaluate its acute effect. However there was no evidence of resolution of vasospasm. In the third'group, resolution of vasospasm was verified on angiograms. Electron microscope studies of basilar arteries of the first two groups revealed degenerative changes of the endothelial cells which were separated from each other and the elastic lamina was irregularly arranged. In the intrathecal lloprost-treated group there was little thickening in the elastic lamina and the endothelial cells were almost normal in structure. These results can be considered as the evidence of the prophylactic effect of lloprost given by the intrathecal route in the prevention of chronic cerebral vasospasm. [Neurol Res 1995; 17: 301-306]     

The effects of endothelin antagonist BQ-610 on cerebral vascular wall following experimental subarachnoid hemorrhage and cerebral vasospasm

Abstract. Endothelin, a potent vasoconstrictor, has been found to increase in the cerebrospinal fluid and serum of patients following subarachnoid hemorrhage (SAH) and to play a major role in the development of cerebral vasospasm. The aim of this study is to investigate the role of endothelin-A antagonist BQ-610 in the experimentally performed cerebral vasospasm following SAH. Thirty New Zealand rabbits were divided into three groups (each n = 10): group A, control group; Group B, SAH group; Group C, treatment (endothelin antagonist BQ-610 treated) group. In the study, the rabbits developed vasospasm after injection of intracisternal autolog blood into the cisterna magna. After cerebral vasospasm development, in group C, endothelin antagonist BQ-610 was injected intracisternally. Morphometrically, basilar artery lumen was constricted 25% and 62% compared to the control group (group A) in the endothelin treated group (group C) and the endothelin untreated group (group B), respectively. Histopathological findings of the basilar artery wall confirmed the therapeutic effect of endothelin antagonist in vasospasm development. Endothelin-A receptor antagonist BQ-610 has a therapeutic effect in the cerebral vasospasm following experimentally performed subarachnoid hemorrhage when used intracisternally.     

The effect of mexiletine on the level of lipid peroxidation and apoptosis of endothelium following experimental subarachnoid hemorrhage

Abstract

Objective: The role of apoptosis in etiopathogenesis of vasospasm is not clearly understood yet. It is widely accepted that protection of the endothelial cells from the process of apoptosis could have beneficial effects on cerebral vasospasm after subarachnoid hemorrhage (SAH). Mexiletine blocks sodium and calcium channels and activates ATP-sensitive K+ channels. Moreover, mexiletine is known to have potent antioxidant effects through inhibiting free-radical production.

Methods: Twenty-one rabbits were allocated into three groups randomly. Group I was sham operated group (n=7). SAH occurred but no medication was given to the Group II rabbits (SAH only group) (n=7). Mexiletine (50 mg/kg, b.i.d., i.p.) was administered just before SAH and continued until 48 hours following SAH to the Group III rabbits (Mexiletine treated group) (n=7). The ApopTag peroxidase in situ apoptosis detection kit (Serologicals Corporation, former Intergen) was used to demonstrate apoptosis in a cross section of basillary arteries. Thiobarbituric acid reactive material was used to determine the lipid peroxidation levels.

Results: There was a statistically significant difference between lipid peroxidation product levels of the control and SAH only groups (p<0.05). The level of lipid peroxidation production in Mexiletine treated group was significantly lower compared with SAH only group (p<0.05) but not significantly higher than the control group (p>0.05).

Discussion: In the present study we investigated the antioxidant action of mexiletine on apoptosis of endothelium following a rabbit SAH model. This experimental study directly suggested that lipid peroxidation is an important step in development of apoptosis in endothelial cells and prevention of structural integrity of endothelial cell should play a beneficial role in attenuation of cerebral vasospasm. Mexiletine treatment prevented the increase in lipid peroxidation and cerebral vasospasm. Examination of endothelial cells by staining specific for apoptosis demonstrated significant protection of cell integrity in the treated group.     

High-Dose Simvastatin Is Effective in Preventing Cerebral Vasospasm after Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study in Korean Patients

ObjectiveThe goal of this study was to assess the effect of high-dose simvastatin on cerebral vasospasm and its clinical outcome after aneurysmal subarachnoid hemorrhage (SAH) in Korean patients.MethodsThis study was designed as a prospective observational cohort study. Its subjects were aneurysmal SAH patients who had undergone aneurysm clipping or coiling. They were assigned to 1 of 3 groups : the 20 mg, 40 mg, and 80 mg simvastatin groups. The primary end-point was the occurrence of symptomatic vasospasm. The clinical outcome was assessed with the modified Rankin Scale (mRS) score after 1 month and 3 months. The risk factors of the development of vasospasm were assessed by logistic regression analysis.ResultsNinety nine patients with aneurysmal SAH were treated and screened. They were sequentially assigned to the 20 mg (n=22), 40 mg (n=34), and 80 mg (n=31) simvastatin groups. Symptomatic vasospasm occurred in 36.4% of the 20 mg group, 8.8% of the 40 mg group, and 3.2% of the 80 mg group (p=0.003). The multiple logistic regression analysis showed that poor Hunt-Hess grades (OR=5.4 and 95% CI=1.09-26.62) and high-dose (80 mg) simvastatin (OR=0.09 and 95% CI=0.1-0.85) were independent factors of symptomatic vasospasm. The clinical outcomes did not show a significant difference among the three groups.ConclusionThis study demonstrated that 80 mg simvastatin treatment was effective in preventing cerebral vasospasm after aneurysmal SAH, but did not improve the clinical outcome in Korean patients.     

The value of transcranial Doppler imaging in children with tuberculous meningitis

Purpose

Transcranial Doppler imaging (TCDI) is potentially a valuable investigational tool in children with tuberculous meningitis (TBM), a condition often complicated by pathology relevant to Doppler imaging such as raised intracranial pressure (ICP) and cerebral vasculopathies.

Methods

Serial TCDI was performed on 20 TBM children with the aim of investigating cerebrovascular haemodynamics and the relationship between pulsatility index (PI) and ICP.

Results

We observed a poor correlation between ICP and PI in children with communicating hydrocephalus (p?=?0.72). No decline in PI was noted following 7 days of medical therapy for communicating hydrocephalus (p?=?0.78) despite a concomitant decline in ICP. Conversely, a decline in PI was noted in all four children with non-communicating hydrocephalus who underwent cerebrospinal fluid diversion. High blood flow velocities (BFV) in all the basal cerebral arteries were observed in 14 children (70 %). The high BFV persisted for 7 days suggesting stenosis due to vasculitis rather than functional vasospasm. Complete middle cerebral artery (MCA) occlusion, subnormal mean MCA velocities (<40 cm/s) and PIs (<0.4) correlated with radiologically proven large cerebral infarcts.

Conclusions

TCDI-derived PI is not a reliable indicator of raised ICP in children with tuberculous hydrocephalus. This may be attributed to individual variation of tuberculous vascular disease, possibly compromising cerebral vascular compliance and resistance. Basal artery stenosis secondary to vasculitis is observed during the acute stage of TBM in the majority of children.     

Fetal posterior cerebral artery in pediatric and adult moyamoya disease: A single-center experience of 480 patients

PurposeIn past pediatric and adult cohort studies of moyamoya disease, the fetal posterior cerebral artery has received less attention. Its relationship with the clinical manifestations and collateral circulation of moyamoya disease or ipsilateral cerebral hemispheres remains unclear.MethodWe summarize the clinical features of patients with and without fetal posterior cerebral artery moyamoya disease from consecutive cases.We explored the relationship between fetal posterior cerebral arteries and collateral circulation in the ipsilateral cerebral hemispheres, as well as differences among different subgroups of patients.According to the morphology, the fetal posterior cerebral artery is divided into complete fetal posterior cerebral artery and partial fetal posterior cerebral artery. Clinical features were classified as: infarction,hemorrhage,and non-stroke in unilateral/bilateral cerebral hemispheres. Collateral circulation is divided into extracranial vascular compensation and leptomeningeal collateral circulation. Digital subtraction angiography and CT/MR were used to evaluate the blood flow status and clinical characteristics of patients with moyamoya disease.ResultA total of 960 cerebral hemispheres from 142 pediatric patients and 338 adult patients were included in the study. A total of 273 (56.9%) patients had 399 cerebral hemispheres (41.6%) with fetal posterior cerebral arteries. Adults with fetal posterior cerebral arteries had lower rates of infarction (24.6%vs37.3%, P =0.005) and were less likely to have bilateral stroke (8.4%vs11.5%, P =0.038). Cerebral hemispheres with fetal posterior cerebral artery were more likely to have anterior cerebral artery and middle cerebral artery stenosis and less likely to have occlusion (P =0.002, 0.001), and less likely to involve the posterior circulation (P < 0.001). The cerebral hemispheres of the fetal posterior cerebral artery had higher leptomeningeal collateral circulation scores. There are significant differences in extracranial vascular compensation between cerebral hemispheres with and without fetal posterior cerebral artery. Adult patients with fetal posterior cerebral artery were more advanced in Suzuki stage (P =0.017).ConclusionsOur results suggest that fetal posterior cerebral artery is associated with infarct manifestations in pediatric and adult moyamoya disease. In the cerebral hemispheres, the fetal posterior cerebral artery is associated with ipsilateral hemispheric anterior and posterior circulation artery injury, extracranial vascular compensation, leptomeningeal collateral circulation compensation, and infarction. Adult patients with fetal posterior cerebral artery were more advanced in Suzuki stage.     

Improved rat model for cerebral vasospasm studies

Abstract

While the rat has been used extensively in subarachnoid hemorrhage (SAH)-cerebral vasospasm studies, concerns exist whether this animal represents a usable model because its time course and pattern of cerebral vasospasm following SAH is not comparable to that observed in man. At present, our knowledge of the rat model is based almost exclusively on studies using a 'single hemorrhage' method. Since there is a positive correlation between severity of cerebral vasospasm, and volume of subarachnoid blood, an obvious question is whether the rat will show modifications in vascular responses when insulted by a second SAH. Here, an SAH was produced in rats using a 'double hemorrhage' method. Following SAH, cerebral arteries showed pathological alterations, significant decreases in luminal perimeter, and increases in arterial wall thickness, over a 7-day post-SAH period. The above vascular features are considered to be indicative of cerebral vasospasm and their presence over a 7-day post-SAH period represents a significant time extension when compared to a single hemorrhage. These modified vascular responses made the double hemorrhaged rat a much-improved animal model. [Neurol Res 2001; 23: 761-766]