Society of NeuroInterventional Surgery Standards of Practice: general considerations.

This is the first in a set of documents intended to standardize techniques, procedures, and practices in the field of endovascular surgical neuroradiology. Standards are meant to define core practices for peer review, comparison, and improvement. Standards and guidelines also form the basic dialogue, reporting, and recommendations for ongoing practices and future development.

Performance and training standards for endovascular ischemic stroke treatment.

Stroke is the third leading cause of death in the USA, Canada, Europe, and Japan. According to the American Heart Association and the American Stroke Association, there are now 750,000 new strokes that occur each year, resulting in 200,000 deaths, or 1 of every 16 deaths, per year in the USA alone. Endovascular therapy for patients with acute ischemic stroke is an area of intense investigation. The American Stroke Association has given a qualified endorsement of intra-arterial thrombolysis in selected patients. Intra-arterial thrombolysis has been studied in two randomized trials and numerous case series. Although two devices have been granted FDA approval with an indication for mechanical stroke thrombectomy, none of these thrombectomy devices has demonstrated efficacy for the improvement of patient outcomes. The purpose of the present document is to define what constitutes adequate training to perform neuroendovascular procedures in patients with acute ischemic stroke and what performance standards should be adopted to assess outcomes. These guidelines have been written and approved by multiple neuroscience societies which historically have been directly involved in the medical, surgical and endovascular care of patients with acute stroke. The participating member organizations of the Neurovascular Coalition involved in the writing and endorsement of this document are the Society of NeuroInterventional Surgery, the American Academy of Neurology, the American Association of Neurological Surgeons/Congress of Neurological Surgeons Cerebrovascular Section, and the Society of Vascular & Interventional Neurology.

Performance and training standards for endovascular ischemic stroke treatment.

Stroke is the third leading cause of death in the USA, Canada, Europe, and Japan. According to the American Heart Association and the American Stroke Association, there are now 750,000 new strokes that occur each year, resulting in 200,000 deaths, or 1 of every 16 deaths, per year in the USA alone. Endovascular therapy for patients with acute ischemic stroke is an area of intense investigation. The American Stroke Association has given a qualified endorsement of intra-arterial thrombolysis in selected patients. Intra-arterial thrombolysis has been studied in two randomized trials and numerous case series. Although two devices have been granted FDA approval with an indication for mechanical stroke thrombectomy, none of these thrombectomy devices has demonstrated efficacy for the improvement of patient outcomes. The purpose of the present document is to define what constitutes adequate training to perform neuroendovascular procedures in patients with acute ischemic stroke and what performance standards should be adopted to assess outcomes. These guidelines have been written and approved by multiple neuroscience societies which historically have been directly involved in the medical, surgical and endovascular care of patients with acute stroke. The participating member organizations of the Neurovascular Coalition involved in the writing and endorsement of this document are the Society of NeuroInterventional Surgery, the American Academy of Neurology, the American Association of Neurological Surgeons/Congress of Neurological Surgeons Cerebrovascular Section, and the Society of Vascular & Interventional Neurology.

Magnetic resonance imaging results can affect therapy decisions in hyperacute stroke care.

BACKGROUND: Despite some limitations, a perfusion/diffusion mismatch can provide a working estimate of the ischemic penumbra in hyperacute stroke and has successfully been used to triage patients. PURPOSE: To evaluate whether the addition of magnetic resonance imaging (MRI) to clinical and non-contrast computed tomography (CT) data alters diagnosis and choice of therapy. MATERIAL AND METHODS: We retrospectively analyzed clinical records, and CT and MRI data fully available in 97 of 117 patients. Upon clinical examination and CT, a diagnosis and treatment path was scored and compared to treatment path after addition of MRI data. The MRI protocol included T2-weighted images, diffusion-weighted images (DWI), and perfusion-weighted images (PWI), and MR angiography (MRA). RESULTS: MRI data were acquired in less than 15 min. In 20 of 97 patients (21%), the diagnosis changed after MRI. In 25 of 97 patients (26%), the presumptive treatment plan was changed after MRI evaluation. Thirteen patients had their treatment changed from thrombolytic to nonthrombolytic therapy. Three patients were changed from nonthrombolytic to intraarterial (IA) thrombolysis. In one patient, treatment was changed from intravenous (IV) to IA thrombolysis, and in five patients it was changed from IA to IV thrombolysis. In two patients, systemic heparin was added to antiplatelet therapy. CONCLUSION: The expansion of the acute stroke protocol to include MRI altered the therapy plan in 26% of our patients. The utility of MRI, shown here to improve patient stratification into best-treatment options, demonstrates the value of using MRI to optimize care in hyperacute stroke patients.

Asymptomatic middle cerebral artery stenosis diagnosed by magnetic resonance angiography.

We reviewed 1440 MRA studies to identify patients with middle cerebral artery stenosis (MCAS). We identified 99 cases, and after reviewing the clinical records, classified 28 as asymptomatic MCAS (AMCAS), a prevalence of 2%. Suspected stroke was the most frequent indication for MRA. Follow-up was available for 21, mean 46.7 months (range 2.4-75.6 months). One stroke occurred in the AMCAS territory (5%), other strokes in five patients (24%). There were five deaths in patients with MCAS; age > 69 (P = 0.045) was the only associated risk factor. This study suggests that patients in whom MRA is performed and shows AMCAS may be at increased risk of strokes in any vascular distribution or of death.

Benefits of perfusion MR imaging relative to diffusion MR imaging in the diagnosis and treatment of hyperacute stroke.

BACKGROUND AND PURPOSE: The development of thrombolytic agents for use with compromised cerebral blood flow has made it critical to quickly identify those patients to best treat. We hypothesized that combined diffusion and perfusion MR imaging adds vital diagnostic value for patients for whom the greatest potential benefits exist and far exceeds the diagnostic value of diffusion MR imaging alone. METHODS: The cases of patients with neurologic symptoms of acute ischemic stroke who underwent ultra-fast emergent MR imaging within 6 hours were reviewed. In all cases, automatic processing yielded isotropic diffusion images and perfusion time-to-peak maps. Images with large vessel distribution ischemia and with mismatched perfusion abnormalities were correlated with patient records. All follow-up images were reviewed and compared with outcomes resulting from hyperacute therapies. RESULTS: For 16 (26%) of 62 patients, hypoperfusion was the best MR imaging evidence of disease distribution, and for 15 of the 16, hypoperfusion (not abnormal diffusion) comprised the only imaging evidence for disease involving large vessels. For seven patients, diffusion imaging findings were entirely normal, and for nine, diffusion imaging delineated abnormal signal in either small vessel distributions or in a notably smaller cortical branch in one case. In all cases, perfusion maps were predictive of eventual lesions, as confirmed by angiography, CT, or subsequent MR imaging. CONCLUSION: If only diffusion MR imaging is used in assessing patients with hyperacute stroke, nearly one quarter of the cases may be incorrectly categorized with respect to the distribution of ischemic at-risk tissue. Addition of perfusion information further enables better categorizing of vascular distribution to allow the best selection among therapeutic options and to improve patient outcomes.

Initial angiographic appearance of intracranial vascular occlusions in acute stroke as a predictor of outcome of thrombolysis: initial experience.

PURPOSE: To determine whether the initial angiographic morphology and location of intracranial arterial occlusions in acute stroke are reliable predictors of success of thrombolysis. MATERIALS AND METHODS: Thirty-three intracranial occlusions were studied in 32 patients who underwent intraarterial thrombolysis with urokinase within 6 hours from clinical onset of stroke symptoms. The initial angiographic appearance of each occlusion was categorized as cutoff, tapered, meniscus, tram-track, or tandem. Following thrombolysis, outcomes were classified as complete, partial, or no recanalization. RESULTS: Complete recanalization was accomplished in 17 of the 33 lesions, partial recanalization in nine, and no effect in seven. Tram-track (n = 3) and tapered (n = 7) lesions demonstrated the highest rates of at least partial recanalization (100% and 86%, respectively), whereas cutoff lesions (n = 13) demonstrated the lowest rate (69%). Intracranial hemorrhage was associated with higher doses of urokinase. Complete recanalization success rates were 60% for M1 lesions (n = 10), 43% for M2 or A2 lesions (n = 14), and 33% for M3 lesions (n = 3). Vertebrobasilar lesion (n = 5) success rates for complete and at least partial recanalization were 80% and 100%, respectively. CONCLUSION: Relationships were found to exist between the success rate of recanalization and initial angiographic lesion location and morphology, which represent important trends; however, further studies with a larger sample size are needed.

Functional evaluation of arteriovenous malformations.

Detailed knowledge of the angioarchitecture of arteriovenous malformations (AVMs) is necessary in determining the optimal timing and method of treatment of these challenging lesions. Many techniques are available for studying the functionality of surrounding cortical structures of AVMs. These include the use of positron emission tomography, functional magnetic resonance imaging, magnetoencephalography, and direct provocative testing of cortical function. The use of these methods to determine flow dynamics and tissue perfusion is also reviewed. These techniques are discussed in the present study, and their judicious utilization will enhance the safety of AVM therapy.

Predictors of clinical improvement, angiographic recanalization, and intracranial hemorrhage after intra-arterial thrombolysis for acute ischemic stroke.

BACKGROUND AND PURPOSE: We sought to evaluate predictors of clinical outcome, angiographic success, and adverse effects after intra-arterial administration of urokinase for acute ischemic stroke. METHODS: We designed a Brain Attack program at University Hospitals of Cleveland for diagnosis and treatment of patients presenting within 6 hours of onset of neurological deficit. Patients with ischemia referable to the carotid circulation were treated with intra-arterial urokinase. Angiographic recanalization was assessed at the end of medication infusion. Intracerebral hemorrhage was investigated immediately after and 24 hours after treatment. Stroke severity was determined, followed by long-term outcome. RESULTS: Fifty-four patients were treated. There was improvement of >/=4 points on the National Institutes of Health Stroke Scale from presentation to 24 hours after onset in 43% of the treated patients, and this was related to the severity of the initial deficit. Forty-eight percent of patients had a Barthel Index score of 95 to 100 at 90 days, and total mortality was 24%. Cranial CT scans revealed intracerebral hemorrhage in 17% of patients in the first 24 hours, and these patients had more severe deficits at presentation. Eighty-seven percent of patients received intravenous heparin after thrombolysis, and 9% of them developed a hemorrhage into infarction. Angiographic recanalization was the rule in complete occlusions of the horizontal portion of the middle cerebral artery, but distal carotid occlusions responded less well to thrombolysis. CONCLUSIONS: The intra-arterial route for thrombolysis allows for greater diagnostic precision and achievement of a higher concentration of the thrombolytic agent in the vicinity of the clot. Disadvantages of this therapy lie in the cost and delay. Severity of stroke and site of angiographic occlusion may be important predictors of successful treatment.

Hyperacute stroke: ultrafast MR imaging to triage patients prior to therapy.

PURPOSE: To test diffusion- and perfusion-weighted MR imaging techniques within the extreme time constraints of stroke evaluation before therapy, and then, with MR imaging, stratify patients into those without ischemia, those with noncortical ischemia, and those with cortical ischemia. MATERIALS AND METHODS: T2-weighted turbo gradient- and spin-echo images and echo-planar diffusion- and perfusion-weighted images were obtained. Trace diffusion-weighted images and time-to-peak perfusion maps were automatically postprocessed and immediately available for interpretation. RESULTS: Forty-one patients with acute stroke symptoms underwent imaging within 6 hours of symptom onset; 35 were eligible for the therapy protocol. The mean time from entering the emergency department to beginning MR imaging was 45 minutes; the mean total MR imaging time was less than 15 minutes. Immediate image analysis directly affected individual clinical management. Four patients showed evidence of no infarct; seven, of lacunar infarct; and 24, of acute cortical infarct. Sixteen patients underwent angiography, thirteen had large-vessel occlusion, eleven were treated intraarterially, and in seven, recanalization was achieved. CONCLUSION: Echo-planar diffusion- and perfusion-weighted MR imaging for acute stroke is feasible and applicable before therapy decisions. Ultrafast MR imaging permitted immediate triage of 35 patients with symptoms of hyperacute stroke and thus helped avoid the risks from angiography and thrombolytic agents in some or spurred the judicious use of more aggressive intervention in others.

Low-flow vascular malformations in the head and neck: safety and feasibility of MR imaging-guided percutaneous sclerotherapy--preliminary experience with 14 procedures in three patients.

Fourteen percutaneous sclerotherapy procedures with magnetic resonance (MR) imaging guidance were performed in three patients with low-flow vascular malformations. All targeted vascular malformation compartments were filled with sclerosing agent without complications in a mean procedural time of 29 minutes. Follow-up imaging demonstrated reduction in size of the treated portions in all patients. In conclusion, sclerotherapy with MR imaging guidance can be performed safely and allows monitoring of injection.

Brain attack: emergency treatment of ischemic stroke.

Thrombolysis has been demonstrated to be an effective treatment for ischemic stroke. The major obstacles to more widespread use of this therapy are lack of awareness that the treatment is possible and the short (less than three hours) therapeutic window. Indiscriminant use of this therapy can lead to an unacceptably high rate of intracerebral hemorrhage. Early recognition of the onset of stroke. Immediate transfer to a suitably equipped treatment facility and careful screening of a computed tomographic scan of the head for signs of early infarction are necessary for the safe administration of intravenous thrombolysis.

Brain attack. Clinical monitoring of early pathophysiologic events.

Stroke is the most prevalent life-threatening neurologic disease. The opportunity to intervene in the acute setting with the use of thrombolytics or neuroprotective agents has led to an evolving interest in obtaining physiologic data points during the acute event. Several imaging techniques are available that can provide pertinent information during the acute phase of an ischemic episode. Some of these techniques, such as diffusion-weighted and perfusion-weighted MR imaging, show exciting promise for defining the ischemic penumbra zone, which is the target of acute intervention.

Thrombolysis for acute ischemic stroke.

The use of thrombolytic agents to restore cerebral blood flow is one of the most notable advances in the treatment of ischemic stroke. This article reviews thrombolytic therapy, its limitations, and the techniques by which thrombolytic agents can be delivered.

Malignant hemangioendothelioma (angiosarcoma) of the skull: plain film, CT, and MR appearance.

Hemangioendothelioma is a rare neoplasm of bone that uncommonly involves the skull. We present a case of grade III malignant hemangioendothelioma (also known as angiosarcoma) of the skull in a 13-year-old boy and describe the plain film, CT, and MR appearance of this neoplasm as well as its histopathology.