Steven W. Hetts

Spinal dural arteriovenous fistulae: clinical features and long-term results.

OBJECTIVEThe goals of this study were to characterize the clinical, radiological, treatment, and outcome data associated with patients diagnosed with spinal dural arteriovenous fistulae (SDAVFs) at a single tertiary care institution over a 20-year period. METHODSA 20-year retrospective study was undertaken at our university hospital. Patients with mixed intracranial and spinal dural fistulas were excluded. A literature review of articles reporting endovascular or combined treatment of SDAVFs was performed. RESULTSBetween 1984 and 2005, our institution diagnosed and treated 63 patients (mean age, 62; 13 women, 50 men) with SDAVFs. The presenting symptoms were consistent with progressive myelopathy, and included lower extremity weakness (33 patients, 52%), parasthesias (19 patients, 30%), back pain (15 patients, 24%), and urinary symptoms (four patients, 6%). Thirty-nine patients underwent an initial endovascular embolization with 27 requiring only this first procedure for complete obliteration. On the other hand, 24 patients underwent an initial surgical procedure with 20 of them treated successfully with a single operation. Endovascular patients presented at mean age 62.3 years (standard deviation [SD], 10.6), were hospitalized for an average of 3.1 days (SD, 2.6), and were followed-up for 39 months (SD, 33). Surgical patients presented at mean age of 65.8 years (SD, 10.3), were hospitalized for 9.8 days (SD, 2.7), and were followed-up for 35 months (SD, 44). A significant improvement in Aminoff-Logue scores was found in both the endovascular and surgery groups (gait, P < 0.001; micturition, P = 0.005). The endovascular group had reduced hospitalization (P = 0.0001). No differences were found in the magnitude of clinical response to treatment. CONCLUSIONSDAVFs most commonly present with progressive myelopathy, yet often remain undiagnosed for months or years. Endovascular therapies and surgical therapies are associated with significantly improved symptoms once the definitive diagnosis of SDAVF is made.

Anomalies of the Corpus Callosum: An MR Analysis of the Phenotypic Spectrum of Associated Malformations

OBJECTIVE We sought to categorize the structural brain anomalies associated with abnormalities of the corpus callosum and anterior and hippocampal commissures in a large cohort. MATERIALS AND METHODS Brain MR images of adult and pediatric patients from our institution and from a national support organization (the ACC Network) were retrospectively evaluated for the type and severity of commissural anomalies and the presence and type of other structural abnormalities. RESULTS Of 142 cases that were reviewed, 82 patients had agenesis of the corpus callosum (ACC), while 60 had hypogenesis of the corpus callosum (HCC). Of the overall cohort, almost all had reduced white matter volume outside the commissures, the majority had malformations of cortical development (most commonly heterotopia or abnormal sulcation), many had noncallosal midline anomalies (including abnormal anterior or hippocampal commissures and interhemispheric cysts and lipomas), and several patients had abnormalities of the cerebellum or brainstem. Sixty-six patients had Probst bundles, which were more common in patients with ACC than in those with HCC. Probst bundles were present in all four patients who had ACC or HCC but no other midline, cortical, or posterior fossa anomalies. CONCLUSION Isolated commissural anomalies were rare in the populations of patients examined. Most cases of ACC and HCC were associated with complex telencephalic, diencephalic, or rhombencephalic malformations. Reduced cerebral hemispheric white matter volume and malformations of cortical development were seen in more than half of the patients, suggesting that many commissural anomalies are part of an overall cerebral dysgenesis. ACC and HCC appear to lie along a dysgenetic spectrum, as opposed to representing distinct disorders.

Density of Thrombus on Admission CT Predicts Revascularization Efficacy in Large Vessel Occlusion Acute Ischemic Stroke

Background and Purpose— Can lysability of large vessel thrombi in acute ischemic stroke be predicted by measuring clot density on admission nonenhanced CT (NECT), postcontrast enhanced CT, or CT angiogram (CTA)? Methods— We retrospectively studied 90 patients with acute large vessel ischemic strokes treated with intravenous (IV) tPA, intra-arterial (IA) tPA, and/or mechanical thrombectomy devices. Clot density [in Hounsfield unit (HU)] was measured on NECT, postcontrast enhanced CT, and CTA. Recanalization was assessed by the Thrombolysis in Cerebral Infarction grading system (TICI) on digital subtraction angiography. Results— Thrombus density on preintervention NECT correlated with postintervention TICI grade regardless of pharmacological (IV tPA r=0.69, IA tPA r=0.72, P<0.0001) or mechanical treatment (r=0.73, P<0.0001). Patients with TICI≥2 demonstrated higher HU on NECT (mean corrected HU IV tPA=1.58, IA tPA=1.66, mechanical treatment=1.7) compared with patients with TICI<2 (IV tPA=1.39, IA tPA=1.4, mechanical treatment=1.3) (P=0.01, 0.006, <0.0001 respectively). There was no association between recanalization and age, sex, baseline National Institute of Health Stroke Scale, treatment method, time to treatment, or clot volume. Conclusions— Thrombi with lower HU on NECT appear to be more resistant to pharmacological lysis and mechanical thrombectomy. Measuring thrombus density on admission NECT provides a rapid method to analyze clot composition, a potentially useful discriminator in selecting the most appropriate reperfusion strategy for an individual patient.

Imaging Recommendations for Acute Stroke and Transient Ischemic Attack Patients: A Joint Statement by the American Society of Neuroradiology, the American College of Radiology, and the Society of NeuroInterventional Surgery

SUMMARY: Stroke is a leading cause of death and disability worldwide. Imaging plays a critical role in evaluating patients suspected of acute stroke and transient ischemic attack, especially before initiating treatment. Over the past few decades, major advances have occurred in stroke imaging and treatment, including Food and Drug Administration approval of recanalization therapies for the treatment of acute ischemic stroke. A wide variety of imaging techniques has become available to assess vascular lesions and brain tissue status in acute stroke patients. However, the practical challenge for physicians is to understand the multiple facets of these imaging techniques, including which imaging techniques to implement and how to optimally use them, given available resources at their local institution. Important considerations include constraints of time, cost, access to imaging modalities, preferences of treating physicians, availability of expertise, and availability of endovascular therapy. The choice of which imaging techniques to employ is impacted by both the time urgency for evaluation of patients and the complexity of the literature on acute stroke imaging. Ideally, imaging algorithms should incorporate techniques that provide optimal benefit for improved patient outcomes without delaying treatment.

Modern meningioma imaging techniques

Steady improvements in imaging modalities have enabled a new realm of capabilities in the identification and assessment of meningiomas. The cross-sectional imaging modalities, MRI and CT, have improved in resolution and fidelity. These modalites now provide not only improved structural information but also insights into functional behavior. MRI has, in particular, proven to have powerful capabilities in evaluating meningiomas because of the ability to assess soft tissue characteristics such as diffusion and vascular supply information, such as perfusion. Recent investigational advances have also been made using a combination of X-ray fluoroscopy for selective catheterization followed by MR perfusion measurement performed with intra-arterial injection of contrast. Together all these modalities provide the radiographer with powerful capbilities for evaluating meningiomas.

Embolectomy for stroke with emergent large vessel occlusion (ELVO): report of the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery

Stroke is the leading cause of adult disability in North America and is the fifth most common cause of death.1 ,2 The natural history of patients with acute ischemic stroke and occlusion of a major intracranial vessel such as the internal carotid artery (ICA), middle cerebral artery (MCA), or basilar artery is dismal, with high rates of mortality and low rates of disability-free survival.3 ,4 We introduce the term ‘Emergent Large Vessel Occlusion (ELVO)’ to describe this clinical scenario. Among acute ischemic stroke, ELVO accounts for the greatest proportion of patients with long-term disability. For the past two decades the use of endovascular therapy has been performed in many centers across the world. The therapies have spanned from infusion of thrombolytic agents5 ,6 to mechanical embolectomy with the introduction of first-generation devices,7 ,8 aspiration-based embolectomy techniques,9 ,10 and the use of stent-retriever based procedures.11 ,12 However, these embolectomy trials were single-arm trials demonstrating safety of the procedure and technique or superiority over another, without direct comparison with standard medical therapy alone. In the past 3 years, several major trials have been published comparing endovascular therapy with standard medical therapy alone. The purpose of this document is to summarize the results of these trials and synthesize the level of evidence supporting the use of embolectomy in patients with ELVO. This document was prepared by the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery, a multidisciplinary society representing the leaders in the field of endovascular therapy for neurovascular disease. The strength of the evidence supporting each recommendation was summarized using a scale previously described by the American Heart Association. ### Role of intravenous thrombolysis In 1996 the FDA approved the use of recombinant tissue plasminogen activator (tPA) for the treatment of acute ischemic stroke …

Pediatric Intracranial Nongalenic Pial Arteriovenous Fistulas: Clinical Features, Angioarchitecture, and Outcomes

BACKGROUND AND PURPOSE: NGAVFs are rare vascular malformations usually presenting in infancy or childhood. We sought to identify clinical and angiographic predictors of clinical outcome for these lesions. MATERIALS AND METHODS: Retrospective review of a neurointerventional data base identified 386 pediatric patients with intracranial AVFs and AVMs, from which a cohort of 25 patients with NGAVF were selected for medical record and imaging analysis. RESULTS: NGAVFs constituted 7.3% of pediatric intracranial vascular lesions with a nondural arteriovenous shunt. Seven of 8 patients who presented in the first month of life had CHF and harbored large, complex fistulas with multiple sites of arteriovenous shunting. Single-hole fistulas predominated later in childhood and more frequently presented with seizures, hemorrhage, or focal neurologic deficits. More treatment procedures were performed in subjects presenting at ≤2 years of age compared with older children (median = 3 versus 2, P = .041), and in those harboring a multi-hole fistula versus those with a single-hole fistula (median = 3 versus 2, P = .003). Eighteen patients (72%) had complete posttreatment elimination of NGAVF shunting. Compared with patients presenting at >2 years of age, patients presenting in the first 2 years of life were more likely to have a multi-hole fistula (100% versus 25%, P = .0001) and to have a poor clinical outcome (54% versus 0%, P = .0052), defined as a pediatric mRS of ≥3. CONCLUSIONS: The morbidity of NGAVF appears higher than previously reported despite a somewhat higher rate of angiographic cure. Poor clinical outcome occurred primarily in patients with multi-hole NGAVFs presenting at ≤2 years of age.

Genomic microarray analysis identifies candidate loci in patients with corpus callosum anomalies.

Absence of the corpus callosum is often associated with cognitive deficits, autism, and epilepsy. Using a genomic microarray, the authors analyzed DNA from 25 patients with radiographically confirmed callosal anomalies and identified three patients with de novo copy number changes in chromosome regions 2q37, 6qter, and 8p. Chromosomal deletions and duplications may be a relatively common cause of cerebral malformations.

Stereotactic radiosurgery at a low marginal dose for the treatment of pediatric arteriovenous malformations: Obliteration, complications, and functional outcomes - Clinical article

UNLABELLED OBJECT.: Stereotactic radiosurgery (SRS) is an established treatment modality for brain arteriovenous malformations (AVMs) in children, but the optimal treatment parameters and associated treatment-related complications are not fully understood. The authors present their single-institution experience of using SRS, at a relatively low marginal dose, to treat AVMs in children for nearly 20 years; they report angiographic outcomes, posttreatment hemorrhage rates, adverse treatment-related events, and functional outcomes. METHODS The authors conducted a retrospective review of 2 cohorts of children (18 years of age or younger) with AVMs treated from 1991 to 1998 and from 2000 to 2010. RESULTS A total of 80 patients with follow-up data after SRS were identified. Mean age at SRS was 12.7 years, and 56% of patients had hemorrhage at the time of presentation. Median target volume was 3.1 cm(3) (range 0.09-62.3 cm(3)), and median prescription marginal dose used was 17.5 Gy (range 12-20 Gy). Angiograms acquired 3 years after treatment were available for 47% of patients; AVM obliteration was achieved in 52% of patients who received a dose of 18-20 Gy and in 16% who received less than 18 Gy. At 5 years after SRS, the cumulative incidence of hemorrhage was 25% (95% CI 16%-37%). No permanent neurological deficits occurred in patients who did not experience posttreatment hemorrhage. Overall, good functional outcomes (modified Rankin Scale Scores 0-2) were observed for 78% of patients; for 66% of patients, functional status improved or remained the same as before treatment. CONCLUSIONS A low marginal dose minimizes SRS-related neurological deficits but leads to low rates of obliteration and high rates of hemorrhage. To maximize AVM obliteration and minimize posttreatment hemorrhage, the authors recommend a prescription marginal dose of 18 Gy or more. In addition, SRS-related symptoms such as headache and seizures should be considered when discussing risks and benefits of SRS for treating AVMs in children.

Initial hospital management of patients with emergent large vessel occlusion (ELVO): report of the standards and guidelines committee of the Society of NeuroInterventional Surgery

Objective To summarize the current literature regarding the initial hospital management of patients with acute ischemic stroke (AIS) secondary to emergent large vessel occlusion (ELVO), and to offer recommendations designed to decrease the time to endovascular treatment (EVT) for appropriately selected patients with stroke. Methods Using guidelines for evidenced-based medicine proposed by the Stroke Council of the American Heart Association, a critical review of all available medical literature supporting best initial medical management of patients with AIS secondary to ELVO was performed. The purpose was to identify processes of care that most expeditiously determine the eligibility of a patient with an acute stroke for interventions including intravenous fibrinolysis with recombinant tissue plasminogen activator (IV tPA) and EVT using mechanical embolectomy. Results This review identifies four elements that are required to achieve timely revascularization in ELVO. (1) In addition to non-contrast CT (NCCT) brain scan, CT angiography should be performed in all patients who meet an institutional threshold for clinical stroke severity. The use of any advanced imaging beyond NCCT should not delay the administration of IV tPA in eligible patients. (2) Activation of the neurointerventional team should occur as soon as possible, based on either confirmation of large vessel occlusion or a prespecified clinical severity threshold. (3) Additional imaging techniques, particularly those intended to physiologically select patients for EVT (CT perfusion and diffusion–perfusion mismatch imaging), may provide additional value, but should not delay EVT. (4) Routine use of general anesthesia during EVT procedures, should be avoided if possible. These workflow recommendations apply to both primary and comprehensive stroke centers and should be tailored to meet the needs of individual institutions. Conclusions Patients with ELVO are at risk for severe neurologic morbidity and mortality. To achieve the best possible clinical outcomes stroke centers must optimize their triage strategies. Strategies that provide patients with ELVO with the fastest access to reperfusion depend upon detail-oriented process improvement.