Rapid progression of traumatic bifrontal contusions to transtentorial herniation: A case report

We report a case of mild to moderate traumatic brain injury in which ICP monitoring or quantitative cerebral perfusion data may have allowed earlier recognition of impending herniation, avoidance of a secondary insult, and ultimately resulted in a better outcome, even though the patient did not meet the standard guidelines of the Brain Trauma Foundation. A thirty-five year old male who presented with traumatic bifrontal contusions and GCS of fourteen and twelve hours later progressed rapidly to having dilated pupils and transtentorial/central herniation over the course of fifteen minutes. The patient was taken emergently for a bifrontal craniectomy. Post operatively he had an acute infarct in the posterolateral left temporal lobe with expected evolution of parenchymal contusions as well as infarcts in the splenium of the corpus callosum, left thalamus and medial right occipital lobe. This case signifies an exception from the guidelines submitted by the Brain Trauma Foundation for intracranial pressure monitoring in patients with severe brain injury.We also point out previous reports which state that in such a patient a more sensitive test for detection would perhaps be quantitative blood flow monitoring, and may have led to a better outcome. We recommend using intracranial pressure monitoring or blood flow measurements to trend patients with bifrontal intraparenchymal contusions and GCS greater than eight to prevent clinically undetected deterioration from transtentorial/central herniation.

Potential use of quantitative bedside CBF monitoring (Xe-CT) for decision making in neurosurgical intensive care

During a 3-year period, mobile xenon-computerized tomography (Xe-CT) for bedside quantitative assessment of cerebral blood flow was used as an integrated tool for decision making during the care of complicated patients in our neurosurgical intensive care units (NSICU), in an attempt to make a preliminary evaluation regarding the usefulness of this method in routine work in the neurosurgical intensive care. With approximately 200 studies involving 75 patients, we identified six different categories where the use of bedside Xe-CT significantly influenced (or, with more experience, could have influenced) the decision making, or facilitated the handling of patients. These categories included identification of problems not apparent from other types of monitoring, avoidance of adverse effects from treatment, titration of standard treatments, evaluation of the vascular resistance reserve, assessment of adequate perfusion pressure and better utilization of resources from access to the bedside cerebral blood flow (CBF) technology. We conclude that quantitative bedside measurements of CBF could be an important addition to the diagnostic and monitoring arsenal of NSICU-tools.

Treatment of dural arteriovenous fistula using ethylene vinyl alcohol (onyx) arterial embolization as the primary modality: short-term results

OBJECT

A dural arteriovenous fistula (DAVF) typically involves meningeal feeding arteries and can cause clinical symptoms ranging from tinnitus to rupture of draining cortical or parenchymal veins. Surgical treatment may be technically demanding. Ethylene vinyl alcohol (Onyx, ev3 Neurovascular) has several properties that make it potentially useful as a primary treatment agent for DAVF. Onyx is expected to be a permanent embolic agent. It should have a decreased risk of catheter retention when compared with other permanent embolic materials.

METHODS

The authors report a series of six patients with symptomatic DAVF who were treated initially with transarterial Onyx embolization and other endovascular techniques.

RESULTS

Five patients had complete occlusion of their DAVF noted on the follow-up angiogram obtained between 2 and 4 months. One patient had residual filling via a small arterial branch that was stable on follow-up angiography. None of the patients had worsening of neurological function. One case was complicated by a retained catheter fragment.

CONCLUSIONS

Transarterial Onyx embolization and other endovascular methods can angiographically obliterate DAVF. In some cases, embolization allowed occlusion of multiple arterial feeding arteries from a single arterial injection. Technically, the embolization was optimized when a microcatheter position immediately adjacent to the point(s) of fistulization was achieved.

PET OEF Reactivity for Hemodynamic Compromise in Occlusive Vascular Disease

BACKGROUND AND PURPOSE

Hemodynamic compromise in symptomatic patients with occlusive vascular disease (OVD) identified by cerebrovascular reserve (CVR) and oxygen extraction fraction (OEF) is an independent predictor of high stroke risk. However, up to 60% of patients compromised by CVR have normal OEF indicating a high rate of discordance. CVR is measured with an acetazolamide challenge, and OEF reactivity (OEFR) to acetazolamide, ie, a hemodynamic challenge, may reveal hemodynamic compromise and less discordance with measurements of CVR.

METHODS

Nine symptomatic patients with OVD were studied by positron emission tomography before and 15 minutes after 15 mg/kg intravenous acetazolamide in the middle cerebral artery territories of each hemisphere.

RESULTS

A close correlation between hemispheric CVR and OEFR was observed. Two hemispheres from two different patients showed an increase in OEF to acetazolamide challenge despite a normal baseline OEF. The two hemispheres showing an increase in OEF in response to acetazolamide were also associated with the lowest CVR and severest white matter hyperintensities.

CONCLUSIONS

These observations suggest that positive OEFR may distinguish hemispheres in hemodynamic compromise despite normal OEF and show less discordance with CVR. However, these preliminary observations require confirmation in a larger study.

Pretreatment ipsilateral regional cortical blood flow influences vessel recanalization in intra-arterial thrombolysis for MCA occlusion

BACKGROUND AND PURPOSE

The aim of acute stroke interventions is to achieve recanalization of the target occluded artery. We sought to determine whether pretreatment cortical cerebral blood flow (CBF) was associated with vessel recanalization in patients undergoing intra-arterial therapy.

METHODS

This is a retrospective analysis of patients who underwent a quantitative xenon CT blood flow study and were noted to have a documented M1 middle cerebral artery (MCA) or carotid terminus occlusion less than 6 hours from symptom onset between January 1997 and April 2001. Twenty-three patients who underwent intra-arterial thrombolysis were included in the analysis. Univariate and multivariate analyses were performed to determine whether pretherapy CBF was correlated to the likelihood of recanalization.

RESULTS

A total of 23 patients were studied in this analysis with a median age of 69 (range 32-81) and median National Institutes of Health Stroke Score of 19 (range, 8-22). Twelve patients (52%) underwent combined intravenous/intra-arterial therapy, and 11 patients (48%) were treated with intra-arterial thrombolytics alone. Successful vessel recanalization (Thrombolysis in Myocardial Infarction classification 2 or 3 flow) occurred in 13 patients (57%). The only variable associated with recanalization in multivariate modeling was mean ipsilateral MCA CBF (odds ratio, 1.25; 95% confidence interval, 1.01-1.54; P = .035). A receiver operating characteristic curve was generated, and a mean ipsilateral MCA CBF threshold of 18 mL/100 g/min was found to be the threshold for successful recanalization.

CONCLUSIONS

Our study suggests that patients with higher mean ipsilateral MCA CBF are more likely to recanalize. The threshold for successful revascularization may be 18 mL/100 g/min. Further study is required to determine whether pretreatment CBF is related to recanalization success.

Quantitative perihematomal blood flow in spontaneous intracerebral hemorrhage predicts in-hospital functional outcome

BACKGROUND AND PURPOSE

Few data on xenon computed tomography-based quantitative cerebral blood flow (CBF) in spontaneous intracerebral hemorrhage have been reported. We correlated perihematomal CBF in a retrospective series of 42 subacute spontaneous intracerebral hemorrhage patients undergoing xenon computed tomography with in-hospital discharge status and mortality.

METHODS

We calculated 3 area-weighted mean CBF values: (1) within the computed tomography-visible rim of perihematomal edema, (2) within a 1-cm marginal radius around the hematoma, and (3) all cortical regions of interest immediately adjacent to the hematoma. Primary outcomes were in-hospital mortality and discharge status (ordinally as 0=home, 1=acute rehabilitation, 2=nursing home, 3=death). Discharge status was used as a surrogate for in-hospital functional outcome.

RESULTS

Median hematoma volume was 14.4 cm(3) (range, 2 to 70). Median perihematomal (low-attenuation rim) CBF was 21.9 cm(3).100 g(-1).min(-1) (range, 6.1 to 81.1), and the median 1-cm marginal radius CBF was 26.8 cm(3).100 g(-1).min(-1) (range, 10.8 to 72.8). The median regional cortical CBF was 26.7 cm(3).100 g(-1).min(-1) (range, 6.9 to 72.6). Eight patients had 1-cm marginal radius or regional cortical CBF values <20 cm(3).100 g(-1).min(-1). Hematoma volume (odds ratio [OR], 1.68 per 10-cm(3) volume; P=0.036) and intraventricular hemorrhage (OR, 1.88 per grade of intraventricular hemorrhage; P=0.036) predicted mortality. Two CBF measures, hydrocephalus, and IVH predicted poor in-hospital functional outcome in bivariate analysis. Each CBF measure (OR, 0.34 to 0.43; P<0.001 to 0.003) and intraventricular hemorrhage (OR, 3.42; P<0.001) predicted in-hospital functional outcome in multivariable analyses.

CONCLUSIONS

Most spontaneous intracerebral hemorrhage patients lack perihematomal penumbra. Perihematomal CBF independently predicts in-hospital discharge status but not in-hospital mortality. Further studies are warranted to determine whether perihematomal CBF predicts long-term functional outcomes.

Magnesium infusion for vasospasm prophylaxis after subarachnoid hemorrhage

Object

Despite the application of current standard therapies, vasospasm continues to result in death or major disability in patients treated for ruptured aneurysms. The authors investigated the effectiveness of continous MgSO4 infusion for vasospasm prophylaxis.

Methods

Seventy-six adults (mean age 54.6 years; 71% women; 92% Caucasian) were included in this comparative matched-cohort study of patients with aneurysmal subarachnoid hemorrhage on the basis of computed tomography (CT) findings. Thirty-eight patients who received continuous MgSO4 infusion were matched for age, race, sex, treatment option, Fisher grade, and Hunt and Hess grade to 38 historical control individuals who did not receive MgSO4 infusion. Twelve grams of MgSO4 in 500 ml normal saline was given intravenously daily for 12 days if the patient presented within 48 hours of aneurysm rupture. Vasospasm was diagnosed on the basis of digital substraction angiography, CT angiography, and transcranial Doppler ultrasonography, and evidence of neurological deterioration.

Symptomatic vasospasm was present at a significantly lower frequency in patients who received MgSO4 infusion (18%) compared with patients who did not receive MgSO4 (42%) (p = 0.025). There was no significant difference in mortality rate at discharge (p = 0.328). A trend toward improved outcome as measured by the modifed Rankin Scale (p = 0.084), but not the Glasgow Outcome Scale (p = 1.0), was seen in the MgSO4-treated group.

Conclusions

Analysis of the results suggests that MgSO4 infusion may have a role in cerebral vasospasm prophylaxis if therapy is initiated within 48 hours of aneurysm rupture.

Reduced pretreatment ipsilateral middle cerebral artery cerebral blood flow is predictive of symptomatic hemorrhage post-intra-arterial thrombolysis in patients with middle cerebral artery occlusion

BACKGROUND AND PURPOSE

Intracerebral hemorrhage (ICH) can be a devastating complication associated with thrombolytic therapy for acute ischemic stroke. We hypothesized that patients with lower prethrombolysis cerebral blood flow (CBF) were at a higher risk of symptomatic ICH (sICH).

METHODS

Twenty-three patients who underwent quantitative CBF assessment with Xenon CT studies for acute stroke before intra-arterial (IA) thrombolysis for a middle cerebral artery (MCA) or internal carotid artery terminus occlusion within 6 hours of symptom onset were studied. Univariate and multivariate analysis were carried out to determine predictors of sICH post-IA thrombolysis. Receiver operating characteristic curves were generated to determine the association between mean ipsilateral CBF and the occurrence of sICH.

RESULTS

The mean age of our cohort was 68+/-12 years and a mean National Institutes of Health Stroke Scale (NIHSS) score of 18+/-3. In univariate analysis, patients with higher percent of core infarct, hyperglycemia, and reduced mean ipsilateral CBF were at risk of sICH. In multivariate analysis only mean ipsilateral CBF was associated with higher rates of sICH (odds ratio 1.58; 95% CI, 1.01 to 2.51; P<0.04). The area under the receiver operating characteristic curve was 0.87 (95% CI, 0.76 to 0.97; P<0.005).

CONCLUSIONS

Patients with lower pre-IA thrombolysis mean ipsilateral MCA CBF are at significantly higher risk for sICH in the setting of a MCA or carotid terminus occlusion. The threshold identified in this study may be useful for selection of patients with acute MCA occlusions for acute stroke thrombolysis.

Differentiating hemodynamic compromise by the OEF response to acetazolamide in occlusive vascular disease

Identification of increased stroke risk in a population of symptomatic patients with occlusive vascular disease (OVD) is presently accomplished by measurement of oxygen extraction fraction (OEF) or cerebrovascular reserve (CVR). However, many regions identified by compromised CVR are not identified by OEF. Our aim was to determine whether the response of OEF to acetazolamide, namely, oxygen extraction fraction response (OEFR) would identify those hemispheres in hemodynamic compromise with normal OEF. Nine patients symptomatic with transient ischemic attacks and strokes, and with occlusive vascular disease were studied. Anatomical MRI scans and T2-weighted images were used to identify and grade subcortical white matter infarcts. PET cerebral blood flow (CBF) and OEF were measured after acetazolamide. The relationship between CVR and oxygen extraction fraction response (OEFR) showed that positive OEFR occurred after acetazolamide despite normal baseline OEF values. The two hemispheres with positive OEFR were also associated with severe (> 3 cm) subcortical white matter infarcts. We found that the OEFR was highly correlated with CVR and identified hemispheres that were hemodynamically compromised despite normal baseline OEF.

Bedside monitoring of CBF with xenon-CT and a mobile scanner: a novel method in neurointensive care

Combining previously independently established techniques our objective was to develop and evaluate a method for bedside qualitative assessment of cerebral blood flow in neurointensive care (NICU) patients. The CT-protocol was optimized using phantoms and comparing a mobile CT-scanner (Tomoscan-M, Philips) with two stationary CT scanners. Thirty-two per cent xenon was delivered with standard equipment (Enhancer 3000). Mean cortical flow in volunteers was 48 ml/min/100 g, with the mean vascular territorial flow varying between 45 and 66 ml/min/100 g. The potential clinical usefulness was illustrated in three patients with vasospasm following subarachnoid haemorrhage. Our conclusion is that quantitative bedside measurements of CBF can be repeatedly performed in an easy and safe way in a standard NICU-setting, using xenon-inhalation and a mobile CT-scanner. The method is useful for the decision-making, and is a good example of how the quality of multi-modality monitoring in the NICU can be developed and further diversified.

Identifying regions of compromised hemodynamics in symptomatic carotid occlusion by cerebrovascular reactivity and oxygen extraction fraction

OBJECTIVES

Oxygen extraction fraction (OEF) and cerebrovascular reserve (CVR) are both proven predictors of stroke risk in symptomatic patients with carotid occlusion. Accordingly, hemispheric comparisons of CVR and OEF are significantly correlated. However, there was also substantial disagreement: hemispheres identified as compromised by CVR were normal by OEF. Our aim was to determine whether regional comparisons could resolve the CVR-OEF discordance. We also studied the relationship between white matter (WM) infarction and hemodynamic compromise.

METHODS

Quantitative CVR and OEF were measured in 12 symptomatic patients with internal carotid artery occlusion. CVR and OEF comparisons were made in the anterior watershed (AWS), middle cerebral artery (MCA) and WM territories using various thresholds for hemodynamic compromise. Associations with WM infarction were also recorded.

RESULTS

Comparison of CVR and OEF for the AWS and MCA showed high sensitivity (100%) with specificities of 83 and 40%, respectively. There was also agreement (k=Cohen's Kappa) for the AWS (k=0.83) and MCA (k=0.39) territories. CVR-OEF discordance was reduced with regional analysis. Hemodynamic compromise was more often found in patients with WM infarction.

DISCUSSION

Regional comparison of CVR and OEF reduced the discordance compared with hemispheric analysis, especially for the AWS territory. Despite the persistence of some regions with compromised CVR and normal OEF, CVR is able to identify all regions with elevated OEF making it a useful screening technology. Future studies are needed to understand whether those remaining regions with compromised CVR are also at increased stroke risk despite normal OEF.

Use of the physical performance test to assess preclinical disability in subjects with asymptomatic carotid artery disease

BACKGROUND AND PURPOSE

The purpose of this study was to determine whether subjects with asymptomatic carotid artery stenosis and occlusion demonstrate deficits in physical performance compared with a comparison group. These deficits may indicate that a person is demonstrating preclinical disability.

SUBJECTS

Seventy-one subjects with no known disease and 39 subjects with asymptomatic carotid artery stenosis of moderate and severe degrees or with occlusion were included.

METHODS

Physical performance was assessed with the 9-item and 7-item versions of the Physical Performance Test (PPT). Individual tasks also were timed for the subjects with disease.

RESULTS

There were significant differences between the comparison group and the subjects with carotid artery stenosis on the 9-item PPT (P<.00) and on the 7-item PPT (P<.03). Subjects with asymptomatic carotid artery stenosis and occlusion demonstrated less than optimal performance on the PPT (9-item PPT, mean=27 of 36; 7-item PPT, mean=21 of 28). Subjects with moderate stenosis were the slowest in performing the task of simulated eating.

DISCUSSION AND CONCLUSION

Subjects with asymptomatic carotid artery stenosis and occlusion exhibited changes in function, as indicated by their performance on the PPT relative to that of a comparison group. This finding may be indicative of preclinical disability, indicating that these people are symptomatic. This indication may affect the medical and surgical options that can be considered for their care.

Xenon CT cerebral blood flow in acute stroke

Acute stroke therapy is evolving rapidly as research moves toward extending the time window for treatment so that more patients can benefit. As physiology-based imaging increasingly is used in patient selection, it is becoming evident that rigid time windows are not applicable to individual patients. Xenon CT has an important role in acute stroke therapeutic intervention as a quantitative, reproducible, rapid, and safe modality, which can provide valuable physiologic data that can optimize patient triage and aid in management.

Comparative overview of brain perfusion imaging techniques

Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are: Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), Xenon-enhanced Computed Tomography (XeCT), Dynamic Perfusion-computed Tomography (PCT), Magnetic Resonance Imaging Dynamic Susceptibility Contrast (DSC), Arterial Spin-Labeling (ASL), and Doppler Ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow (CBF) or volume (CBV). All of them are used to characterize the same types of pathological conditions. However, each technique has its own advantages and drawbacks. This article addresses the main imaging techniques dedicated to brain hemodynamics. It represents a comparative overview, established by consensus among specialists of the various techniques. For clinicians, this paper should offers a clearer picture of the pros and cons of currently available brain perfusion imaging techniques, and assist them in choosing the proper method in every specific clinical setting.

Cerebral hemodynamic and metabolic profiles in fulminant hepatic failure: relationship to outcome

The purpose of this retrospective study was to examine the potential role of cerebral hemodynamic and metabolic factors in the outcome of patients with fulminant hepatic failure (FHF). Based on the literature, a hypothetical model was proposed in which physiologic changes progress sequentially in five phases, as defined by intracranial pressure (ICP) and cerebral blood flow (CBF) measurements. Seventy-six cerebral physiologic profiles were obtained in 26 patients (2 to 5 studies each) within 6 days of FHF diagnosis. ICP was continuously measured by an extradural fiber optic monitor. Global CBF estimates were obtained by xenon clearance techniques. Jugular venous and peripheral artery catheters permitted calculation of cerebral arteriovenous oxygen differences (AVDO2), from which cerebral metabolic rate for oxygen (CMRO2) was derived. A depressed CMRO2 was found in all patients. There was no evidence of cerebral ischemia as indicated by elevated AVDO2s. Instead, over 65% of the patients revealed cerebral hyperemia. Eight of the 26 patients underwent orthotopic liver transplantation-all recovered neurologically, including 6 with elevated ICPs. Of the 18 patients receiving medical treatment only, all 7 with increased ICP died in contrast to 9 survivors whose ICP remained normal (P < 0.004). Hyperemia, per se, was not related to outcome, although it occurred more frequently at the time of ICP elevations. Six patients were studied during brain death. All 6 revealed malignant intracranial hypertension, preceded by hyperemia. In conclusion, the above findings are consistent with the hypothetical model proposed. Prospective longitudinal studies are recommended to determine the precise evolution of the pathophysiologic changes.

Mental health, anxiety, and depression in patients with cerebral aneurysms

Object. Aneurysm disease and its treatment can have an adverse impact on mental health, yet the affects of cerebral aneurysms on general mental health, anxiety, and depression are poorly understood.

Methods. Patients with cerebral aneurysms who were seen at a neurosurgery clinic underwent a structured interview, completed the Hospital Anxiety and Depression Scale and the Medical Outcomes Study 12-item Short Form Health Survey (providing a mental component summary [MCS] score for general mental health), and were assigned functional status scores based on the Glasgow Outcome Scale (GOS), Rankin Scale, and Barthel Index. Rank-order methods were used to assess the relationship between mental health, aneurysm characteristics and history, and functional status. Data were collected in 166 patients (71% women) with a mean age of 53.7 years. Depression was present in 8% of the study population and an anxiety disorder in 17%. Patients with both an unsecured aneurysm and a history of subarachnoid hemorrhage (SAH) tended toward higher anxiety scores (p = 0.086). Higher depression scores were associated with a decreased functional status on the GOS (p = 0.015) and Rankin Scale (p = 0.010). The mean 6 standard deviation adjusted MCS score (37.9 ± 7.1) was significantly less than that of the US population (p < 0.001). Lower MCS scores were associated with a decreased functional status on the GOS (p = 0.052), Rankin Scale (p < 0.001), and Barthel Index (p = 0.002).

Conclusions. Patients with cerebral aneurysms have increased levels of anxiety and depression and poor general mental health. Those who have experienced an SAH and harbor an unsecured cerebral aneurysm demonstrate increased levels of anxiety. A lower functional status in patients with aneurysms is associated with depression and decreased general mental health.

Comparative overview of brain perfusion imaging techniques

BACKGROUND AND PURPOSE

Numerous imaging techniques have been developed and applied to evaluate brain hemodynamics. Among these are positron emission tomography, single photon emission computed tomography, Xenon-enhanced computed tomography, dynamic perfusion computed tomography, MRI dynamic susceptibility contrast, arterial spin labeling, and Doppler ultrasound. These techniques give similar information about brain hemodynamics in the form of parameters such as cerebral blood flow or cerebral blood volume. All of them are used to characterize the same types of pathological conditions. However, each technique has its own advantages and drawbacks.

SUMMARY OF REVIEW

This article addresses the main imaging techniques dedicated to brain hemodynamics. It represents a comparative overview established by consensus among specialists of the various techniques.

CONCLUSIONS

For clinicians, this article should offer a clearer picture of the pros and cons of currently available brain perfusion imaging techniques and assist them in choosing the proper method for every specific clinical setting.

Sodium MR Imaging of Acute and Subacute Stroke for Assessment of Tissue Viability

Sodium MR imaging at 3.0 T provides high-quality images in acceptable acquisition times that allow assessment of tissue viability as defined by maintenance of sodium ion homeostasis. This application is made feasible for clinical stroke evaluation by an efficient projection pulse sequence with extremely short echo time values. This twisted projection imaging provides high signal-to-noise images at adequate resolution (5 x 5 x 5 mm(3)) in less than 10 minutes at 3.0 T. The images are quantified as tissue sodium concentration (TSC) maps that can be interpreted directly in terms of tissue viability. With infarction, baseline TSC values of less than 45 mmol/L increase at variable rates to approximately 70 mmol/L, allowing monitoring of the progression of stroke pathophysiology.

The short form-12 and the measurement of health status in patients with cerebral aneurysms: performance, validity, and reliability

OBJECT

Cerebral aneurysms can affect a patient's health status by rupture and stroke, impingement on neural structures, treatment side effects, or psychological stress. The authors assessed the performance, validity, and reliability of the Short Form-12 (SF-12), a self-administered written survey instrument, to assess health status in patients with cerebral aneurysms.

METHODS

A cohort of 170 patients with cerebral aneurysms who were seen at a neurosurgery clinic underwent structured interviews including measurement of their health statuses (SF-12 physical component summary [PCS] and mental component summary [MCS]), functional status (Glasgow Outcome Scale score, modified Rankin Scale score, and Barthel Index), and mental health (Hospital Anxiety and Depression Scale score). The SF-12 scores were compared with US population norms by performing t-tests with unequal variances. The validity of the SF-12 was assessed by comparing the PCS and MCS scores with each patient's functional status and mental health scores by using rank-order methods. Inter-item reliability was assessed using the Cronbach alpha statistic. Patients with cerebral aneurysms had decreased health status PCS and MCS scores when compared with population norms (p < 0.001 for all). A history of subarachnoid hemorrhage (SAH) (p = 0.006) and previous surgical or endovascular treatment (p = 0.047) was associated with worse PCS scores. The validity of the SF-12 was supported by the relationship between the PCS and MCS scores and the patient's functional status and mental health (p < 0.001 for all). The reliability of the SF-12 was documented by the Cronbach alpha statistic (alpha = 0.76).

CONCLUSIONS

Patients with cerebral aneurysms have a diminished physical and mental health status as measured using the SF-12. The presence of SAH and aneurysm treatment are associated with a worse physical health status. The SF-12 is a valid and reliable instrument for measuring health status in patients with cerebral aneurysms.

A failure to communicate: patients with cerebral aneurysms and vascular neurosurgeons

OBJECTIVE

To assess communication between vascular neurosurgeons and their patients with unruptured cerebral aneurysms about treatment options and expected outcomes.

METHODS

Vascular neurosurgeons and their patients with cerebral aneurysms were surveyed immediately following outpatient appointments in a neurosurgery clinic. Data collected included how well the patient understood their aneurysm treatment options, the risks of a poor outcome from various treatments, and the consensus "best" treatment. Patient and neurosurgeon responses were measured using Likert scales, multiple choice questions, and visual analogue scales. Agreement between patient and neurosurgeon was assessed with kappa scores. The Wilcoxon sign rank test was used to compare visual analogue scale responses.

RESULTS

Data for 44 patient-neurosurgeon pairs were collected. Only 61% of patient-neurosurgeon pairs agreed on the best treatment plan for the patient's aneurysm (kappa = 0.51, moderate agreement). Among the neurosurgeons, agreement with their patients ranged from 82% (kappa = 0.77, almost perfect agreement) to 52% (kappa = 0.37, fair agreement). Patients estimated much higher risks of stroke or death from surgical clipping, endovascular embolisation, or no intervention compared with the estimates offered by their neurosurgeons (surgical clipping: patient 36% v neurosurgeon 13%, p<0.001; endovascular embolisation: patient 35% v neurosurgeon 19%, p = 0.040; and no

INTERVENTION

patient 63% v neurosurgeon 25%, p<0.001).

CONCLUSIONS

Following consultation with a vascular neurosurgeon, many patients with cerebral aneurysms have an inaccurate understanding of their aneurysm treatment plan and an exaggerated sense of the risks of aneurysmal disease and treatment.

Identification and quantification of the hydroxyeicosatetraenoic acids, 20-HETE and 12-HETE, in the cerebrospinal fluid after subarachnoid hemorrhage

PURPOSE

The monohydroxylated metabolite of arachidonic acid, 20-hydroxyeicosatetraenoic acid (20-HETE), is a potent vasoconstrictor of cerebral microvessels. 20-HETE formation is substantially elevated in the cerebral spinal fluid (CSF) in the rat subarachnoid hemorrhage (SAH) model. The presence of 20-HETE in human CSF has not been demonstrated. Therefore, it was the purpose of this study to determine if HETE metabolites are present in human CSF after SAH.

METHODS

CSF samples were collected daily from four SAH patients over 15 days. HETE metabolites were separated by HPLC with identification by ion-trap MS/MS and quantification via single quadrupole MS operating in negative single ion monitoring mode.

RESULTS

Two major metabolites were identified as 12-HETE and 20-HETE. 20-HETE maximal concentrations were 2.9 and 0.7 ng/ml at approximately 70 h in the two patients with symptomatic cerebral vasospasm (SV) after SAH. Concentrations of 12-HETE in these patients peaked at 21.9 ng/ml and 2.8 ng/ml. Concentrations of 20-HETE and 12-HETE were non-detectible in the majority of the samples obtained from two matched SAH patients without SV.

CONCLUSIONS

This study is the first to demonstrate that 20-HETE and 12-HETE are present in the CSF of SAH patients at physiologically relevant concentrations. Based on this information future prospective studies will allow for the delineation of the role of these metabolites in the pathogenesis of SAH.

Identification of hemodynamic compromise by cerebrovascular reserve and oxygen extraction fraction in occlusive vascular disease

Cerebrovascular reserve (CVR) and oxygen extraction fraction (OEF) are used to identify hemodynamic compromise in symptomatic patients with carotid occlusive vascular disease, but evidence suggests that they are not equivalent. The authors studied the relationship between CVR and OEF to evaluate their equivalence and stages of hemodynamic compromise. Symptomatic patients (N = 12) with carotid occlusion were studied by stable xenon-computed tomography CBF after intravenous acetazolamide administration for CVR, followed within 24 hours by positron emission tomography (PET) for OEF. Middle cerebral artery territories were analyzed by hemisphere and level. Hemispheric subcortical white matter infarctions were graded with magnetic resonance imaging. Both hemispheric and level analysis of CVR and OEF showed a significant (P = 0.001), negative linear relationship [CVR (%) = -1.5 (OEF) + 83.4, (r = -0.57, P = 0.001, n = 24]. However, 37.5% of the hemispheres showed compromised CVR but normal OEF and were associated (P = 0.019) with subcortical white matter infarction. CMRO2 was elevated in stage II hemodynamic compromise (CVR < 10%, OEF > 50%). CVR and OEF showed a significant negative linear relationship in stage II hemodynamic compromise but revealed hemispheres in hemodynamic compromise by CVR but normal OEF that were associated with subcortical white matter infarction.

The impact of cardiac complications on outcome in the SAH population

OBJECTIVES

To determine the impact of cardiac complications (CdCs) on outcomes in patients with acute subarachnoid hemorrhage (SAH).

PATIENTS AND METHODS

Eighty-one adult aneurysmal SAH patients with a fisher grade >1 and/or a Hunt and Hess grade >2 were recruited for this study. CdCs were defined as electrocardiogram (ECG) changes, myocardial necrosis, arrythmias, or pulmonary edema. Outcomes were assessed at 3, 6 and 12 months by telephone interview using the Modified Rankin Scale (MRS), Glasgow Outcome Scale (GOS), Barthel Index and Medical Outcome study Short Form-36 (SF-36).

RESULTS

The CdCs occurred in 33% of patients. The most common CdCs were arrythmias and pulmonary edema (30%). There was no significant difference in mortality between the two groups. At 3 months there was a significant difference in the Barthel (P = 0.007) and the SF-36 (P = 0.014) with trends in the GOS (P = 0.049) and the MRS (P = 0.063). At 6 months a significant difference remained in the SF-36 (P = 0.028) and a trend in the Barthel (P = 0.069).

CONCLUSION

Results show that CdCs may negatively impact outcomes in SAH patients up to 6 months following hemorrhage.

The Effects of Admission Alcohol Level on Cerebral Blood Flow and Outcomes after Severe Traumatic Brain Injury

This study examined the relationship between admission serum alcohol level (ETOH) and cerebral blood flow (CBF) and outcomes in the adult traumatic brain injured (TBI) population. We hypothesized that individuals with ETOH > 100 mg/dL will have decreased blood flow on admission and poorer outcomes. Eighty subjects, age 16-65, with severe TBI (Glasgow Coma Score [GCS] </= 8) were entered into the study. Correlational analysis assessed the relationship between ETOH and admission severity of injury scores as measured by Marshall and APACHE III scores, CBF, and outcomes. Comparison of CBF and outcomes between groups based on admission serum ETOH level was conducted with analysis of variance and post hoc Scheffé analyses as well as regression analysis. There was a significant relationship between serum ETOH level and GCS (p = 0.02), but not APACHE III scores (p = 0.12) or Marshall scores (p = 0.27). There was a significant correlation between global CBF and serum ETOH level (p = 0.02). There was no statistically significant association between serum ETOH level and GOS at 3 (p = 0.97), 6 (p= 0.56), or 12 (p = 0.73) months after injury. The data indicated that serum ETOH levels > 100 mg/dL at the time of admission after a TBI were associated with a decrease in global CBF. Elevated serum ETOH level at time of injury did not, however, impact outcomes.

The Cortical Ischemic Core and Not the Consistently Present Penumbra Is a Determinant of Clinical Outcome in Acute Middle Cerebral Artery Occlusion

BACKGROUND AND PURPOSE

Patient selection for acute stroke therapy based on physiology rather than on time may lead to expansion of the therapeutic window, improved outcomes, and fewer side effects than currently achieved. This approach requires early determination of both irreversible (core) and reversible (penumbra) ischemia in acute stroke.

METHODS

Using established perfusion thresholds, we characterized the relationship among core, penumbra, and brain tissue perfused above penumbral thresholds (non-core/non-penumbra [NC/NP]) in 36 patients with middle cerebral artery (MCA) stem occlusion who underwent quantitative cerebral blood flow (CBF) assessment with xenon-enhanced CT within 6 hours of symptom onset.

RESULTS

While great variability in the mean+/-SD percentage of core (37.6+/-18.7) and NC/NP (30.3+/-16.6) was observed, the percentage of penumbra was relatively constant from individual to individual, constituting approximately one third of the cortical MCA territory (32.1+/-7). In univariable and multivariable analyses, percent core and not percent penumbra was significantly associated with outcome.

CONCLUSIONS

In acute MCA occlusion, penumbra is consistently present within a relatively narrow range, despite great variability in the size of core. This may explain why the core and not the penumbra is the main determinant of outcome in our group of patients. Recanalization therapy in acute MCA occlusion should ideally be guided by diagnostic methods capable of rapidly and reliably identifying irreversible ischemia.

Influence of delaying treatment after symptoms develop from subarachnoid hemorrhage: a preliminary analysis

Patients experiencing subarachnoid hemorrhage (SAH) symptoms may delay seeking medical attention, not realizing the severity of these symptoms. The purposes of this study were to determine (a) the length of time between the development of SAH symptoms in patients and when treatment was initially sought and (b) whether the delay in hospital admission had an effect on patient outcomes. Inclusion criteria were age (18-75 years) and diagnosis of severe SAH. Consent was obtained on 90 eligible patients admitted to the neurovascular intensive care unit. Outcomes were assessed at 3 months using the Glasgow Outcome Scale (GOS) and Modified Rankin Scale (MRS). Initial time delay, calculated by subtracting the time of initial symptom development from the time of admission to the emergency department (ED), ranged from 0.08 to 103 hours. There was no relationship between the initial time delay and GOS or MRS scores. There was a significant difference between the time to initial ED admission to a trauma ED and to a community ED; patients were admitted within 2.7 hours to a trauma ED admission, compared to 7 hours for a community ED admission. There was a significant relationship between the Hunt and Hess Scale and GOS and between the Hunt and Hess and MRS. There was a significant relationship between the Fisher Grade and GOS and between the Fisher Grade and MRS. This study shows that patients may delay treatment for nearly 7 hours after initial symptoms develop. This suggests that laypersons are not aware of SAH symptoms, thereby delaying ED admission and care. The study also suggests that more severe symptoms upon admission to the ED were related to poorer outcomes. Initial clinical presentation is a useful predictor for SAH outcomes. This study supports the idea that the general public needs to be educated on the symptoms of SAH.

Symptomatic cavernous sinus aneurysms: management and outcome after carotid occlusion and selective cerebral revascularization

BACKGROUND AND PURPOSE

Therapeutic internal carotid artery (ICA) occlusion for symptomatic intracavernous artery aneurysms can result in ischemic infarction despite normal clinical balloon test occlusion (BTO). We evaluated outcomes in patients with symptomatic cavernous sinus aneurysms in whom clinical BTO was normal, who underwent carotid occlusion with selective bypass surgery guided by physiologic BTO using quantitative cerebral blood flow (CBF) analysis by means of stable xenon-enhanced CT.

METHODS

After a normal clinical BTO, 26 consecutive patients with symptomatic cavernous sinus aneurysms underwent a baseline xenon-enhanced CT CBF analysis followed by a second CBF analysis, during which repeat BTO was performed. Patients with a decrease in cortical CBF to below 30 mL/100 g/min were considered moderate risk and those with greater than 30 mL/100 g/min were low risk for developing postocclusion ischemic infarction. Moderate-risk patients underwent cerebral revascularization followed by proximal carotid occlusion. Low-risk patients underwent carotid occlusion alone. Patients were clinically followed up for at least 3 months after carotid occlusion. All patients underwent head CT at least 1 month after carotid occlusion.

RESULTS

Eight patients were moderate risk and 18 low risk. Mean follow-up was 15.3 months. Mean CT follow-up was 10.2 months. No low-risk patient developed a postocclusion ischemic deficit by examination or infarct by CT. One patient in the moderate-risk group developed right hemiparesis and a left posterior middle cerebral artery infarction by CT 2 months after carotid occlusion.

CONCLUSION

In this series, BTO combined with quantitative CBF analysis was a safe and reliable technique for identification of patients at risk for ischemic infarction after carotid occlusion, despite a normal clinical BTO.

CT-based assessment of acute stroke: CT, CT angiography, and xenon-enhanced CT cerebral blood flow

BACKGROUND AND PURPOSE

Only a small percentage of acute-stroke patients receive thrombolytic therapy because of time constraints and the risks associated with thrombolytic therapy. We sought to determine whether xenon-enhanced CT (XeCT) cerebral blood flow (CBF) and/or CT angiography (CTA) in conjunction with CT can distinguish subgroups of acute ischemic stroke victims and thereby better predict the subgroups most likely to benefit and not to benefit from thrombolytic therapy.

METHODS

An analysis of 51 patients who had a CT, CTA, and stable XeCT CBF examination within 24 hours of stroke symptom onset was conducted. These initial radiographic studies and National Institutes of Health Stroke Scale score on admission were assessed to determine whether they could predict new infarction on follow-up CT or discharge disposition by use of the Fisher exact test to determine statistical significance.

RESULTS

Patients with no infarction on initial CT and normal XeCT CBF had significantly fewer new infarctions and were discharged home more often than those with compromised CBF. The same held true for patients with an open internal carotid artery and middle cerebral artery by CTA and normal CT compared with those with an occluded internal carotid artery and/or middle cerebral artery by CTA. Either was superior to CT and the National Institutes of Health Stroke Scale in prediction of outcome. Both enable the selection of a group of patients not identifiable by CT alone that would do well without being exposed to the risks of thrombolytic therapy. This study included too few patients to statistically assess the role of combining CTA and XeCT CBF information.

CONCLUSIONS

The combination of CT, CTA, and Xe/CT CBF does define potentially significant subgroups of patients. The utility of this classification is supported by the observation that CTA and XeCT CBF are superior to CT alone in predicting infarction on follow-up CT and clinical outcome. This information may be useful in selecting patients for acute-stroke treatment.

Cerebrovascular reserve in patients with carotid occlusive disease assessed by stable xenon-enhanced ct cerebral blood flow and transcranial Doppler

BACKGROUND AND PURPOSE

Cerebrovascular reserve (CVR) by both transcranial Doppler ultrasonography (TCD) and quantitative cerebral blood flow (CBF) can identify subgroups of patients at increased risk for stroke. A direct comparison of CVR measurements obtained with both technologies in patients with cerebrovascular occlusive disease is lacking.

METHODS

CVRs before and after acetazolamide administration (1 g IV) were measured by TCD insonation of the middle cerebral artery (MCA) and CBF obtained with stable xenon CT (Xe/CT) in 38 patients with carotid occlusive disease. Sensitivity/specificity calculations were based on 2 Xe/CT MCA values: an average over 4 levels and the level with the lowest percent change in CBF. Compromised CVR was defined as no reactivity or a decrease in reactivity.

RESULTS

Using the analysis of the systolic TCD, we found that velocity changes compared with the average Xe/CT MCA CVR showed a sensitivity of 33%, specificity of 90.6%, positive predictive value of 54.5%, and negative predictive value of 80%. The sensitivity of TCD compared with the lowest Xe/CT CBF CVR was 35.5%, specificity and positive predictive values were 100%, and negative predictive value was 66.7%. The index of validity was between 72% and 76%.

CONCLUSIONS

TCD is much less sensitive than Xe/CT CBF in identifying patients with compromised CVR. This may be a result of the inability of TCD to identify patients with compromised reserves when their MCA blood flow comes from collateral sources. The lack of correlation between TCD and Xe/CT CBF for identifying patients with compromised CVR should be considered when stroke risk assessments are made by TCD.

Cerebral revascularization for cerebral ischemia and stroke prevention in patients with atherosclerotic occlusive disease: defining the population that benefits

The decision to perform a revascularization procedure on a patient who may or may not benefit from it must be based on an understanding of the impact of spontaneous or therapeutic vascular occlusion on the physiologic, by which the cerebral circulation compensates for vascular occlusions. This impact is patient specific and requires examination of a number of possible physiologic parameters.

Molecular anatomy of an intracranial aneurysm: coordinated expression of genes involved in wound healing and tissue remodeling

BACKGROUND AND PURPOSE

Approximately 6% of human beings harbor an unruptured intracranial aneurysm. Each year in the United States, >30 000 people suffer a ruptured intracranial aneurysm, resulting in subarachnoid hemorrhage. Despite the high incidence and catastrophic consequences of a ruptured intracranial aneurysm and the fact that there is considerable evidence that predisposition to intracranial aneurysm has a strong genetic component, very little is understood with regard to the pathology and pathogenesis of this disease.

METHODS

To begin characterizing the molecular pathology of intracranial aneurysm, we used a global gene expression analysis approach (SAGE-Lite) in combination with a novel data-mining approach to perform a high-resolution transcript analysis of a single intracranial aneurysm, obtained from a 3-year-old girl.

RESULTS

SAGE-Lite provides a detailed molecular snapshot of a single intracranial aneurysm. These data suggest that, at least in this specific case, aneurysmal dilation results in a highly dynamic cellular environment in which extensive wound healing and tissue/extracellular matrix remodeling are taking place. Specifically, we observed significant overexpression of genes encoding extracellular matrix components (eg, COL3A1, COL1A1, COL1A2, COL6A1, COL6A2, elastin) and genes involved in extracellular matrix turnover (TIMP-3, OSF-2), cell adhesion and antiadhesion (SPARC, hevin), cytokinesis (PNUTL2), and cell migration (tetraspanin-5).

CONCLUSIONS

Although these are preliminary data, representing analysis of only one individual, we present a unique first insight into the molecular basis of aneurysmal disease and define numerous candidate markers for future biochemical, physiological, and genetic studies of intracranial aneurysm. Products of these genes will be the focus of future studies in wider sample sets.

Comparison of functional magnetic resonance imaging with positron emission tomography and magnetoencephalography to identify the motor cortex in a patient with an arteriovenous malformation

Alterations in gyral contour made it difficult to identify the motor cortex thought to be near an arteriovenous malformation (AVM) in a 24-year-old man considered for stereotactic radiosurgery. Functional imaging in three modalities was performed preoperatively to compare the reliability of localization using functional magnetic resonance imaging (fMRI) on a conventional scanner with positron emission tomography (PET) and magnetoencephalography (MEG). Similar tasks were used for each imaging modality in an attempt to activate and identify the sensory and motor cortex. Data from all three modalities converged for the sensory task, and fMRI and PET data converged for the motor task. The right hemisphere motor strip was localized adjacent and anterior to the AVM. These data were used in planning the radiosurgery isodose configuration to the AVM in order to reduce the irradiation of motor cortex parenchyma. A postoperative fMRI study was also performed using newer techniques to reduce head motion artifact and to improve signal-to-noise ratio. The data confirmed the conclusions derived from the preoperative evaluations. This study demonstrates how conventional MRI scanners can be used for functional studies of use in surgical planning.

Lack of agreement between transcranial Doppler and Xe/CT cerebral blood flow in the detection of cerebrovascular reserves in patients with carotid occlusive disease

P41

Introduction: Transcranial Doppler ultrasonography (TCD) has been used to identify patients with compromised cerebrovascular reserve(CVR). Patients with compromised CVR have been shown to have an increased risk for stroke. Transcranial Doppler, however, has not been compared to the high resolution quantitative cerebral blood flow (CBF) method of stable xenon enhanced computed tomography (Xe/CT). Methods: Cerebrovascular reserves before and after acetazolamide administration (1 gram, i.v.) were measured by TCD insonation of the middle cerebral artery (MCA) and Xe/CT CBF. Thirty-one patients with carotid occlusive disease were studied. Calculations were based on two methods; for the first method Xe/CT CBF values were averaged over 4 levels of the MCA, the second method used the value for the MCA level with the lowest percent change. The threshold for identifying compromised CVR versus non-compromised CVR was 0% change(two standard deviations below normal)for both the TCD and the Xe/CT CBF analyses. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. Results: For the average MCA territory analyses TCD compared to Xe/CT CBF had a 42% sensitivity, a 90% specificity, a 50% positive predictive value and a 86% negative predictive value. The comparison of TCD to Xe/CT using the lowest MCA territory analysis for the Xe/CT CBF values also gave a sensitivity of 42%. The specificity and positive predictive value were both 100% and the negative predictive value was 72%. Discussion/ Conclusion: The sensitivity of TCD compared to Xe/CT CBF indicates a significant lack of agreement in identifing those patients with compromised CVR. The negative predictive value indicates that the number of patients identified with positive CVR (i.e. negative for compromised reserves)is not the same as with Xe/CT CBF. Physicians should consider this lack of correlation when using TCD to identify patients with compromised CVR. A direct prospective comparison to PET or a clinical prediction of stroke by Xe/CT needs to be done in order to determine the best technology.

Patterns of core and penumbra in acute MI occlusion and their clinical correlates

P51

Background and Purpose: The ischemic penumbra is composed of neurons that are functionally impaired but structurally intact, and thus potentially salvageable. Identifying the penumbra and its relationship with the ischemic core may lead to a more physiologic selection of patients who might benefit from recanalization therapy. We sought to explore the core/penumbra relationship by quantitatively measuring cerebral blood flow (CBF) in patients with acute M1 occlusion. Methods: 19 patients with M1 occlusion proven by CT angiography or conventional cerebral angiography underwent a Xe-CT/CBF study within 6 hours of symptoms onset. Mean CBF values were measured in the ipsilateral cortical MCA territory. The core was defined as areas with CBF< 8 ml/100g/min and the penumbra was defined as areas with CBF 9–20 ml/100g/min. Findings were correlated with the admission NIH stroke scale (NIHSS). Results: In 6/19 patients (31.5%)(group 1), the size of the penumbra was greater than twice the size of the core. In 8/19 patients (42.1%) (group 2), the size of the penumbra was approximately equal the size of the core. In 5/19 patients (26.8%)(group 3) the size of the penumbra was less than half the size of the core. The median core volumes for each of the three groups, expressed as percentage of core relative to ipsilateral cortical MCA territory, increased from group 1 to group 3. While there was a trend towards a correlation between the admission NIHSS and the combined core and penumbral volumes, no such correlation could be established between admission NIHSS and core or penumbral volumes alone. Conclusions: In the first 6 hours after M1 occlusion, penumbral volumes that are larger than or equal to core volumes are present in 14 out of 19 patients. A smaller core volume is associated with an increased penumbra to core ratio. The admission NIHSS in patients with M1 occlusion correlates with the combined volumes of core and penumbra.