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.

Serial triple quantum sodium MRI during non-human primate focal brain ischemia.

Triple quantum (TQ) sodium MRI techniques with clinically acceptable 18-min data acquisition times were demonstrated in vivo in a nonhuman primate model of focal brain ischemia. Focal brain ischemia was induced in four animals using embolization coils to occlude the posterior cerebral artery, and a balloon catheter to occlude the middle cerebral artery. A statistically significant increase (P < 0.001) in the TQ sodium MRI signal intensity in the ischemic hemisphere relative to the contralateral hemisphere was seen at all time points in all four animals. This increased TQ sodium MRI signal intensity was demonstrated as early as 0.6 hr after the onset of ischemia. The TQ sodium MRI hyperintensity corresponded to the anatomical location of the ischemic cortex, as indicated by the registration of the TQ imaging data with anatomical proton MRI data. The results demonstrate that early after the onset of ischemia, there was an increase in the TQ signal intensity in the ischemic hemisphere, and a negligible change in the single quantum (SQ) signal intensity.

Triple/Single quantum filtered sodium MRI of acute brain ischemia.

The effectiveness of reperfusion therapies during acute brain ischemia depends on the viability of the underperfused tissue. Specifically, when the ischemic tissue is viable reperfusion leads to improved clinical outcome. However, when the ischemic tissue is non-viable, reperfusion therapy can lead to intra-cerebral hemorrhage and/or an accelerated rate of ischemia formation. Perfusion and diffusion weighted proton MRI (DW MRI) are well-established techniques for the early detection of brain ischemia but are unable to positively establish the viability of the tissue. Tissue sodium concentration (TSC) has been shown to exhibit a linear and reversible response for many hours after ischemia onset. Because sodium accumulation in tissue is closely related to its metabolic status, we believe that the rate of TSC accumulation during evolving ischemia could provide useful information about tissue viability during evolving ischemia. In this paper, we discuss the technical details leading to the application of triple quantum (TQ) sodium MRI for the monitoring of brain ischemia. The proposed methods are then demonstrated in a non-human primate model of temporary middle cerebral artery (MCA) occlusion.

Aneurysm rupture during endovascular coiling: effects on cerebral transit time and neurophysiologic monitoring and the benefits of early ventriculostomy: case report.

OBJECTIVE AND IMPORTANCE: We report a case of intra-operative aneurysm rupture during endovascular therapy and document the effects of rupture on cerebral transit times and neurophysiologic monitoring. The effects of early ventriculostomy are clearly documented. CLINICAL PRESENTATION: A 42-year-old man with Hunt and Hess grade 1, Fisher grade 3 subarachnoid hemorrhage secondary to a 5 mm anterior communicating artery aneurysm underwent coil embolization. INTERVENTION: Endovascular therapy was complicated by intraprocedural aneurysm rupture. Changes in cerebral transit time and electroencephalography along with somatosensory evoked potentials were documented as were improvement in these parameters following aneurysm obliteration and ventriculostomy placement. The patient awoke without deficit and was discharged 2 weeks later with a grossly normal examination. CONCLUSION: Early recognition of aneurysm rupture during coil embolization and prompt aneurysm obliteration and reduction in intracranial hypertension can lead to acceptable patient outcomes. Use of neurophysiologic monitoring in the intubated patient can help the neurosurgeon determine the need for cerebrospinal fluid drainage in such situations.

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.

Rupture of intracranial aneurysms during endovascular coiling: management and outcomes.

OBJECTIVE: In this study, the incidence, etiologies, and management with respect to clinical outcome of patients with iatrogenic aneurysmal rupture during attempted coil embolization of intracranial aneurysms are reviewed. METHODS: A retrospective analysis was conducted of 274 patients with intracranial aneurysms treated with Guglielmi detachable coils over a 6-year period from 1994 to 2000. Patient medical records were examined for demographic data, aneurysm location, the number of coils deployed preceding and after aneurysmal rupture, the etiology of the rupture, and the clinical status on admission and at the time of discharge. RESULTS: Of 274 patients with intracranial aneurysms treated with coil embolization, six (2%) had an intraprocedural rupture. Of these six, two were women and four were men. The mean age was 67 years (range, 52-85 yr). Mean follow-up time was 8 months (range, 0-25 mo). Aneurysmal rupture resulted from detachment of the last coil in three patients, detachment of the third coil (of four) in one patient, and insertion of the first coil in another patient. In one patient, the aneurysmal rupture was a result of catheter advancement before detachment of the last coil. The Glasgow Outcome Scale score at last follow-up examination was 1 in two patients, 2 in two patients, and 5 in two patients. CONCLUSION: The rate of rupture of aneurysms during coil embolization is approximately 2 to 4%. The clinical outcome may be related to the timing of the rupture and the number of coils placed before rupture. If extravasation of contrast agent is seen, which suggests intraprocedural rupture, further coil deposition should be attempted if safely possible.

Transluminal stent-assisted coil embolization of a vertebral confluence aneurysm: technique report.

BACKGROUND: Recent advances in stent technology have allowed for negotiation of often tortuous posterior circulation intracranial vasculature. Stent-assisted coil embolization is a novel treatment for complex wide-necked aneurysms, as stents provide a buttress that allows for coil deposition while preventing coil herniation into the parent vessel lumen. We describe a case of stent-assisted coil embolization of a complex wide-necked vertebral confluence aneurysm. CASE DESCRIPTION: A 61-year-old woman presented with a Hunt-Hess III, Fisher Grade III subarachnoid hemorrhage secondary to a ruptured vertebral confluence aneurysm demonstrated on angiography. The patient underwent emergent angiography and attempted coiling of a vertebral confluence aneurysm. Because of the aneurysm's complex wide neck and the presence of subclavian steal syndrome, the coils repeatedly herniated into the left vertebral and basilar artery lumina. A flexible coronary stent was deployed across the aneurysm neck, preventing coil herniation and allowing for greater coil deposition. The patient tolerated the procedure and underwent repeat coiling 2 months postoperatively because of mild coil compaction. This resulted in 100% occlusion and the patient is neurologically normal except for a sixth nerve palsy which had been present after the hemorrhage. CONCLUSION: Recent advances in stent technology allow negotiation of the tortuous posterior circulation vasculature. Stent-assisted coil embolization of complex, wide-necked vertebral confluence aneurysms may be an alternative intervention for these surgically challenging lesions.

Transluminal stent-assisted angiplasty of the intracranial vertebrobasilar system for medically refractory, posterior circulation ischemia: early results.

OBJECTIVE: Symptomatic vertebrobasilar artery stenosis portends a poor prognosis, even with medical therapy. Surgical intervention is associated with considerable morbidity, and percutaneous angioplasty alone has demonstrated mixed results, with significant complications. Recent advances in stent technology have allowed for a novel treatment of symptomatic, medically refractory, vertebrobasilar artery stenosis. We report on a series of patients with medically refractory, posterior circulation stenosis who were treated with transluminal angioplasty and stenting at two medical centers in the United States. METHODS: A retrospective analysis of data for 11 consecutive patients with symptomatic, medically refractory, intracranial, vertebral or basilar artery stenosis was performed. All patients were treated with percutaneous transluminal angioplasty and stenting. Short-term clinical and angiographic follow-up data were obtained. RESULTS: Among 11 patients who were treated with stent-assisted angioplasty of the basilar or vertebral arteries, there were three periprocedural deaths and one delayed death after a pontine stroke. Other complications included a second pontine infarction, with subsequent residual diplopia. The remaining seven patients (64%) experienced symptom resolution and have resumed their preprocedural activities of daily living. Angiographic follow-up examinations demonstrated good patency of the stented lesions for five of seven survivors (71%); one patient exhibited minimal intrastent intimal hyperplasia, and another patient developed new stenosis proximal to the stent and also developed an aneurysm within the stented portion of the basilar artery. The last patient exhibited 40% narrowing of the treated portion of the vessel lumen. CONCLUSION: Recent advances in stent technology allow negotiation of the proximal posterior circulation vasculature. Although the treatment of vertebrobasilar artery stenosis with angioplasty and stenting is promising, long-term angiographic and clinical follow-up monitoring of a larger patient population is needed.

Cluster analysis and patterns of findings on cranial magnetic resonance imaging of the elderly: the Cardiovascular Health Study.

OBJECTIVE: To characterize patterns of findings on cranial magnetic resonance imaging (MRI) of the elderly using a statistical technique called cluster analysis. SUBJECTS AND METHODS: The Cardiovascular Health Study is a population-based, longitudinal study of 5888 people 65 years and older. Of these, 3230 underwent cranial MRI scans, which were coded for presence of infarcts and grades for white matter, ventricles, and sulci. Cluster analysis separated participants into 5 clusters based solely on patterns of MRI findings. Participants comprising each cluster were contrasted with respect to cardiovascular risk factors and clinical manifestations. RESULTS: One cluster was low on all the MRI findings (normal) and another was high on all of them (complex infarcts). Another cluster had evidence for infarcts alone (simple infarcts), whereas the last 2 clusters lacked infarcts, one having enlarged ventricles and sulci (atrophy) and the other having prominent white matter changes and enlarged ventricles (leukoaraiosis). Factors that distinguished these clusters in a discriminant analysis were age, sex, several measures of hypertension, internal carotid artery wall thickness, smoking, and prevalent claudication before the MRI. The atrophy group had the highest percentage of men and the normal group had the lowest. Cognitive and motor performance also differed across clusters, with the atrophy cluster performing better than may have been expected. CONCLUSIONS: These MRI patterns identified participants with different vascular disease risk factors and clinical manifestations. Results of these exploratory analyses warrant consideration in other populations of elderly people. Such patterns may provide clues about the pathophysiology of structural brain changes in the elderly.

Endoscopic and endoscopic-assisted surgery for juvenile angiofibroma.

OBJECTIVES/HYPOTHESIS: The mainstay treatment for juvenile angiofibromas is surgery. Endoscopic techniques have been applied to the resection of juvenile angiofibromas. The aim of the study is to establish the efficacy of endoscopic and endoscopic-assisted techniques for the removal of juvenile angiofibromas. STUDY DESIGN: Retrospective review. METHODS: Retrospective review was made of all patients with juvenile angiofibromas who were treated with endoscopic and endoscopic-assisted surgery from January 1994 to July 1999. RESULTS: Fifteen tumors in 13 patients were removed using endoscopic or endoscopic-assisted surgeries. In 11 patients, endoscopic surgery or endoscopic-assisted surgery (or both) was successful and the patients remained without evidence of disease at a median follow-up of 34 months. In two patients tumor persisted, which was detected during routine follow-up less than 6 months after the initial surgery. These tumors were managed with a second endoscopic or endoscopic-assisted surgery, and patients remained without evidence of disease. We encountered one postoperative complication, a progressive optic neuropathy that was successfully managed with endoscopic decompression. CONCLUSIONS: Endoscopic and endoscopic-assisted surgery is a feasible alternative or adjunct to traditional techniques.

Tube angulation improves angiographic targeting of arteriovenous malformations during stereotactic radiosurgery.

Stereotactic radiosurgery using the 201 Cobalt-60 source Gamma Knife has been an effective method for obliterating selected cerebral arteriovenous malformations (AVMs). For more than 20,000 patients worldwide, angiography under stereotactic conditions has been the main imaging modality for defining and targeting the AVM nidus. The role of angulation of the X-ray tube for angiographic localization of the AVM during stereotactic Gamma Knife radiosurgery was studied with a phantom. Using current dose-planning software, tube angulation facilitated target visualization, improved three-dimensional dose planning, and has been consistent with the increased probability of complete nidus obliteration.

Endovascular management of a basilar artery false aneurysm secondary to endoscopic third ventriculostomy: case report.

OBJECTIVE AND IMPORTANCE: Third ventriculostomy for the management of noncommunicating hydrocephalus is a commonly performed procedure with a 5% complication rate. One of the known complications is basilar artery injury. CLINICAL PRESENTATION: We report a case of basilar artery injury, intraventricular hemorrhage, and false aneurysm formation in a 30-month-old boy after third ventricle floor fenestration. INTERVENTION: The false aneurysm was managed with endovascular trapping by use of Guglielmi detachable coils without morbidity. CONCLUSION: Endovascular therapy can be used successfully to manage vascular injury after third ventriculostomy.

An endovascular primate model for the production of a middle cerebral artery ischemic infarction.

SUMMARY: An endovascular model for producing and studying middle cerebral artery acute ischemic strokes was developed to avoid the need for an open surgical approach to the middle cerebral, anterior cerebral, posterior cerebral and internal carotid arteries. Endovascular occlusion of these vessels followed by Xenon-CT cerebral blood flow study confirmed the production of a middle cerebral artery distribution infarct in two primates. The methodology, advantages and drawbacks of this model are discussed.

Remote effects of acute ischemic stroke: A xenon CT cerebral blood flow study.

OBJECTIVE: The purpose of this study was to verify transhemispheric diaschisis in the early hours after an ischemic event. METHODS: XeCT cerebral blood flow (CBF) studies within 8 h of stroke were studied in 23 patients. Mean CBF was evaluated in the ischemic area, contralateral hemisphere and ipsilateral cerebellum. RESULTS: A severe CBF reduction was found in the ischemic area (mean 9 +/- 3 ml/100 g/min). The mean CBF in the unaffected hemisphere (33 +/- 10 ml/100 g/min) was 35% less compared to the normal mean value. CBF was decreased in the cerebellum ipsilateral to the stroke (mean 31 +/- 12 ml/100 g/min) suggesting a blood flow depression of the whole brain. CONCLUSIONS: During the initial hours of cerebral ischemia, the asymptomatic hemisphere demonstrated CBF depression that was part of the global flow reduction.

Clinical correlates of ventricular and sulcal size on cranial magnetic resonance imaging of 3,301 elderly people. The Cardiovascular Health Study. Collaborative Research Group.

To identify potential risk factors for and clinical manifestations of ventricular and sulcal enlargement on cranial magnetic resonance imaging (MRI), 3,301 community-dwelling people 65 years or older without a history of stroke or transient ischemic attack underwent extensive standardized evaluations and MRI. In the multivariate model, increased age and white matter grade on MRI were the dominant risk factors for ventricular and sulcal grade. For ventricular grade, other than race, for which non-Blacks had higher grades, models for men and women shared no other factors. For sulcal grades, models for men and women shared variables reflecting cigarette smoking and diabetes. Clinical features were correlated more strongly with ventricular than sulcal grade and more strongly for women than men. Significant age-adjusted correlations between ventricular grade and the Digit-Symbol Substitution Test were found for men and women. Prospective studies will be needed to extend findings of this cross-sectional analysis.

Intra-arterial thrombolysis for carotid circulation ischemia.

Recanalization of acutely occluded arteries in the carotid territory, particularly the middle cerebral artery, by intra-arterial delivery of thrombolytic drugs, has advanced dramatically over the last decade. Randomized prospective studies have begun to show the potential impact of this form of intervention. Still, patient selection, therapeutic window, critical care support, and experience of the management team are clearly the determining features for the success of intra-arterial thrombolysis. The use of thrombolytic agents currently available, and research involving the next generation of these agents, open a field that shows promise for the improvement of outcomes of patients whose typical prognosis is poor.

Removal of a thrombus from the sigmoid and transverse sinuses with a rheolytic thrombectomy catheter.

A rheolytic thrombectomy catheter was used to remove thrombus without thrombolytics from the sigmoid and transverse sinuses of a 34-year-old woman. Using small, high-flow fluid jets and Venturi-effect suction, this catheter allowed mechanical removal of thrombus. This technique may obviate the need for thrombolytic agents and the risks associated with their use.

Factors affecting survival rates for acute vertebrobasilar artery occlusions treated with intra-arterial thrombolytic therapy: a meta-analytical approach.

OBJECTIVE: To determine whether recanalization, coma at presentation, or clot location in the basilar artery influences the relative mortality risk after intra-arterial thrombolytic therapy for acute vertebrobasilar artery occlusions. METHODS: Studies were identified using the MEDLINE database for January 1987 to November 1997. Series were included if they involved 10 or more patients with basilar or vertebrobasilar artery occlusions, used urokinase and/or recombinant tissue plasminogen activator, and were written in English. A fixed-effect meta-analysis approach was used to estimate the risk of death with the aforementioned risk factors. Each study was weighted according to sample size. Relative risks were calculated with 95% confidence intervals. RESULTS: As calculated from peer-reviewed published data, the relative mortality risk for patients for whom recanalization was attempted but not achieved was 2.34 (95% confidence interval, 1.48-3.71; n = 126). Coma at presentation was associated with a relative mortality risk of 1.95 (95% confidence interval, 1.26-2.99; n = 145). Clot locations in the distal one-third of the basilar artery were shown to favor survival, compared with clots located in the proximal and/or middle portions of the basilar artery (relative risk, 0.52; 95% confidence interval, 0.31-0.86; n = 126). CONCLUSION: The combined data suggest that coma at presentation has an independent and adverse effect on survival rates. Complete recanalization, distal clot location, and responsiveness at the time of presentation are statistically significant factors for increased patient survival rates.

Advanced CT imaging (functional CT).

Computed tomography can provide anatomic and functional information about the brain. The conventional CT of the brain can be coupled with a cerebral blood flow examination using the stable xenon CT technique and with a CT angiography. Distinct subgroups of patients based on variations in cerebral blood flow and vascular pathology have been demonstrated. The addition of the functional information has become extremely important in triaging and determining the appropriate intervention in the patient with an acute neurological deficit.