Cyst formation following radiosurgery for AVMs: report of 3 cases.

BACKGROUND: Stereotactically-focused radiosurgery (SRS) for the treatment of arteriovenous malformations (AVM) has been in widespread use for over two decades. Over this timeframe the indications for treatment, standardization of radiation dosage, and the results expected from treatment have been elaborated. Less well known are the long-term complications associated with SRS. We report three patients who had SRS for the treatment of AVM who developed a cyst at the site of treatment as a late complication. METHODS: From 201 patients treated by SRS for an AVM, three developed a cyst at the treatment site. Their clinical presentation, the characteristics of the AVMs and the treatment were reviewed, as well as similar cases gleaned from the literature. RESULTS: Three women, aged 28-43 years, had an AVM treated by: craniotomy and clipping of arterial feeders followed by SRS, by craniotomy for resection followed by SRS or by endovascular embolization and SRS. The patients did well following treatment but two of them developed a symptomatic and the other an asymptomatic cyst at the treatment site 3-19 years later. The symptomatic patients underwent marsupialization of the cyst and the other is under observation. CONCLUSION: Stereotactic radiosurgery is an established and safe treatment for patients with AVMs. Delayed cyst formation can occur many years after treatment and long term follow-up is indicated in patients whose AVM has been treated with SRS.

Time for a Time Window Extension: Insights from Late Presenters in the ESCAPE Trial.

BACKGROUND AND PURPOSE: The safety and efficacy of endovascular therapy for large-artery stroke in the extended time window is not yet well-established. We performed a subgroup analysis on subjects enrolled within an extended time window in the Endovascular Treatment for Small Core and Proximal Occlusion Ischemic Stroke (ESCAPE) trial. MATERIALS AND METHODS: Fifty-nine of 315 subjects (33 in the intervention group and 26 in the control group) were randomized in the ESCAPE trial between 5.5 and 12 hours after last seen healthy (likely to have groin puncture administered 6 hours after that). Treatment effect sizes for all relevant outcomes (90-day mRS shift, mRS 0-2, mRS 0-1, and 24-hour NIHSS scores and intracerebral hemorrhage) were reported using unadjusted and adjusted analyses. RESULTS: There was no evidence of treatment heterogeneity between subjects in the early and late windows. Treatment effect favoring intervention was seen across all clinical outcomes in the extended time window (absolute risk difference of 19.3% for mRS 0-2 at 90 days). There were more asymptomatic intracerebral hemorrhage events within the intervention arm (48.5% versus 11.5%, P = .004) but no difference in symptomatic intracerebral hemorrhage. CONCLUSIONS: Patients with an extended time window could potentially benefit from endovascular treatment. Ongoing randomized controlled trials using imaging to identify late presenters with favorable brain physiology will help cement the paradigm of using time windows to select the population for acute imaging and imaging to select individual patients for therapy.

Canadian Stroke Best Practice Recommendations for Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care, 6th Edition, Update 2018.

The 2018 update of the Canadian Stroke Best Practice Recommendations for Acute Stroke Management, 6th edition, is a comprehensive summary of current evidence-based recommendations, appropriate for use by healthcare providers and system planners caring for persons with very recent symptoms of acute stroke or transient ischemic attack. The recommendations are intended for use by a interdisciplinary team of clinicians across a wide range of settings and highlight key elements involved in prehospital and Emergency Department care, acute treatments for ischemic stroke, and acute inpatient care. The most notable changes included in this 6th edition are the renaming of the module and its integration of the formerly separate modules on prehospital and emergency care and acute inpatient stroke care. The new module, Acute Stroke Management: Prehospital, Emergency Department, and Acute Inpatient Stroke Care is now a single, comprehensive module addressing the most important aspects of acute stroke care delivery. Other notable changes include the removal of two sections related to the emergency management of intracerebral hemorrhage and subarachnoid hemorrhage. These topics are covered in a new, dedicated module, to be released later this year. The most significant recommendation updates are for neuroimaging; the extension of the time window for endovascular thrombectomy treatment out to 24 h; considerations for treating a highly selected group of people with stroke of unknown time of onset; and recommendations for dual antiplatelet therapy for a limited duration after acute minor ischemic stroke and transient ischemic attack. This module also emphasizes the need for increased public and healthcare provider's recognition of the signs of stroke and immediate actions to take; the important expanding role of paramedics and all emergency medical services personnel; arriving at a stroke-enabled Emergency Department without delay; and launching local healthcare institution code stroke protocols. Revisions have also been made to the recommendations for the triage and assessment of risk of recurrent stroke after transient ischemic attack/minor stroke and suggested urgency levels for investigations and initiation of management strategies. The goal of this updated guideline is to optimize stroke care across Canada, by reducing practice variations and reducing the gap between current knowledge and clinical practice.

Generalized cortical dysplasia manifested by diffusely thick cerebral cortex.

Unilateral or bilateral rolandic macrogyria has been described as a cause of epilepsy and, in some cases, retardation. Tissue from the periphery of these lesions shows the changes of focal cortical dysplasia. Evidence reported herein suggests that cortical dysplasia may also be generalized. Two patients with intractable epilepsy and mental retardation had diffusely abnormal, thick cortex, shallow gyri, and poor demarcation of gray and white matter. One patient had an anterior callosotomy that led to considerable improvement of the epilepsy. Cortical layers 5 and 6 could not be differentiated on biopsy material. The white matter was poorly myelinated and contained clusters of heterotopic neurons. This syndrome, a congenital disorder of neuronal migration, with prolonged survival, represents a mild form of lissencephaly. It can be diagnosed during life by computed tomography or magnetic resonance scanning.

Long-term follow-up of acute partial transverse myelopathy.

We carried out a prospective, long-term, combined clinical and MRI follow-up study on 15 patients hospitalized at the Montreal Neurological Institute between 1985 and 1988 with a diagnosis of acute partial transverse myelopathy of unknown etiology. Twelve of the 15 (80%) developed clinically definite or lab-supported definite multiple sclerosis (MS) by the end of a mean follow-up period of 38.5 months. The presence of CNS periventricular white matter lesions by cranial MRI at onset increased the likelihood of development of MS to 93%.

Intracerebral cavernous angiomas.

We studied 31 patients with histologically verified intracerebral cavernous angiomas. Twenty-two patients were symptomatic; nine were asymptomatic. All 22 symptomatic patients had seizures, three had intracranial hemorrhage, and one had signs of a space-occupying lesion. Twenty-seven lesions were located in the neocortex, three in the brainstem, and one in the cerebellum; all exhibited characteristic gross and microscopic features of cavernous angiomas. CT identified the location and extent of the lesion in 16 of 27 cases. Six of seven lesions demonstrated contrast enhancement, and ten of 27 scans harbored densities consistent with intracerebral calcium. Angiography was performed in 17 cases and was completely normal in eight. MRI revealed mixed signal intensity centrally with a ring of decreased signal intensity peripherally on T2-weighted images and was diagnostic in five cases. Surgical treatment offers an excellent prognosis for seizure control in patients with such lesions.

Diffuse cortical dysplasia, or the 'double cortex' syndrome: the clinical and epileptic spectrum in 10 patients.

Diffuse neuronal migration disorders associated with epilepsy can now be recognized by modern neuroimaging techniques, particularly high-resolution MRI. We report 10 patients with a recently described MRI picture of continuous or generalized band heterotopia underlying the cortical mantle, giving the appearance of a "double cortex." They have epilepsy, and almost all have mental retardation. The epileptic disorder varies in nature and degree of severity. Patients may present with infantile spasms, a Lennox-Gastaut syndrome, or other forms of secondary generalized or multifocal epilepsy. Response to medical treatment is variable. Callosotomy may lead to considerable reduction of drop attacks, present in 60%. Mental retardation is usually mild or moderate, and only rarely severe. It correlates with the type of epileptic syndrome, and is greater in patients with more disorganized cortex overlying the heterotopia. Recognition of this entity by MRI is important for appropriate diagnosis of the epileptic disorder, planning of therapeutic strategy, and prognosis.

Magnetic resonance imaging shows specific abnormalities in the MELAS syndrome.

The MELAS syndrome (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) can be difficult to identify. We report MRI abnormalities that we believe are specific to this disorder in three patients with complete or partial MELAS syndrome. The patients all showed an unusual pattern on T2-weighted MRI with multifocal areas of hyperintense signal confined to the cortex of the cerebrum, cerebellum, and adjacent white matter. Some images suggested selective cortical involvement of deeper layers only. Deep white matter was relatively spared, distinguishing this from usual cerebrovascular disease or the edema after status epilepticus. Specificity of these findings is further suggested by a good correlation of these findings with the previously described unique postmortem brain pathology of MELAS.

Cortical dysplasia: an immunocytochemical study of three patients.

Human cortical dysplastic lesions are frequently associated with severe partial epilepsies. We report an immunocytochemical investigation on cortical tissue from three surgically treated patients, 20, 38, and 14 years old, with intractable epilepsy due to cortical dysplasia. The studies were performed using antibodies recognizing cytoskeletal proteins, calcium-binding proteins, and some subunits of glutamate receptors. The specimens from the three patients displayed common features: (1) focal cytoarchitectural abnormalities with an increased number of giant pyramidal neurons through all cortical layers except layer I; (2) large, round-shaped balloon cells mainly concentrated in the deepest part of the cortex and in the white matter; (3) a decrease of calcium binding protein immunopositive gamma-aminobutyric acid (GABA)ergic neurons; and (4) abnormal baskets of parvalbumin-positive terminals around the excitatory (pyramidal and large, round-shaped) neurons. These data provide evidence that the epileptogenicity in these types of cortical dysplasia is due to an increase in excitatory neurons coupled with a decrease in GABAergic interneurons.

X-linked malformations of neuronal migration.

Malformations of neuronal migration such as lissencephaly (agyria-pachygyria spectrum) are well-known causes of mental retardation and epilepsy that are often genetic. For example, isolated lissencephaly sequence and Miller-Dieker syndrome are caused by deletions involving a lissencephaly gene in chromosome 17p13.3, while many other malformation syndromes have autosomal recessive inheritance. In this paper, we review evidence supporting the existence of two distinct X-linked malformations of neuronal migration. X-linked lissencephaly and subcortical band heterotopia (XLIS) presents with sporadic or familial mental retardation and epilepsy. The brain malformation varies from classical lissencephaly, which is observed in males, to subcortical band heterotopia, which is observed primarily in females. The XLIS gene is located in chromosome Xq22.3 based on the breakpoint of an X-autosomal translocation. Bilateral periventricular nodular heterotopia (BPNH) usually presents with sporadic or familial epilepsy with normal intelligence, primarily in females, although we have evaluated two boys with BPNH and severe mental retardation. The gene for BPNH has been mapped to chromosome Xq28 based on linkage studies in multiplex families and observation of a subtle structural abnormality in one of the boys with BPNH and severe mental retardation.

Postural displacement of the brain: feasibility of using CT for determination of stereotaxic coordinates.

Ten patients were studied with computed tomography (CT) in an attempt to determine if CT could be used preoperatively to establish stereotaxic coordinates for an operation and to find out more about how postural changes affect the position of the brain. Certain well defined cerebral structures were chosen as anatomic landmarks, and their relation to the skull determined with the patient in the supine, lateral, and prone positions. An external helmet fixation system was used to ensure consistent and reproducible CT slices. No displacement of the brain structures was observed in any of the positions, so it may be assumed that it is feasible to use CT-generated preoperative stereotaxic coordinates for reference during an operation, regardless of the patient's position. Four of the 10 patients were examined after lumbar intrathecal administration of metrizamide (200 mg I/ml). This small amount of positive contrast material did not seem to influence the position of the brain.

MR imaging of epidermoid cysts.

Nine patients with epidermoid cysts, five of them pathologically proved, were evaluated with MR imaging. Six patients also had CT. The cases were reviewed to evaluate the MR appearance of epidermoid cysts and to compare the MR findings with those of CT. The epidermoid cysts demonstrated low-signal intensity on T1-weighted MR images and hyperintensity on T2-weighted images. In five cases the cysts appeared heterogeneously iso- to hyperintense on the intermediate echo, and were surrounded by a thin rim of high signal intensity, which we believe was caused by encased CSF. The CT scans showed the cysts as low-density, well-demarcated lesions that do not enhance after infusion with contrast material. We conclude that MR is superior to CT in the evaluation of epidermoid cysts and is particularly useful in surgical planning.

Intracerebral gangliogliomas in patients with partial complex seizures: CT and MR imaging findings.

The clinical and radiologic findings in 19 patients with partial complex seizures and surgically proved intracerebral gangliogliomas were reviewed to characterize the radiologic features of these lesions. The CT and MR findings were not specific. On CT the gangliogliomas can be hypodense with no enhancement and they often have calcifications. On MR these tumors have a wide variety of signals. In five of our cases the tumor had a high-intensity signal with a cystlike component on proton density- and T2-weighted images. In five cases the lesion had an inhomogeneously intense signal on proton density-weighted images and high signal intensity on T2-weighted images. The tumor had high-intensity signal on both proton density- and T2-weighted images in four patients. Finally, in two cases the MR findings were normal. We recommend MR as the examination of choice for patients with partial complex seizures because it allows an artifact-free evaluation of the temporal region. However, CT should also be performed in order to recognize calcifications that may be missed on the MR examination.

Iopamidol vs. metrizamide myelography: clinical comparison of side effects.

One hundred myelographies with iopamidol and 100 with metrizamide were performed in order to compare the side effects of the two contrast media after injection into the spinal subarachnoid space. All patients were observed for a follow-up period of at least 4 days. The most frequently observed side effect, headache, was more common, of longer duration, and more severe with the use of metrizamide than with iopamidol. Only neck pain was more common with iopamidol. More severe side effects such as meningeal irritation, psychoorganic syndrome, and epileptic seizures occurred only with metrizamide. The results seem to indicate a lower neurotoxicity and better patient tolerance for iopamidol than for metrizamide.

Cerebral amyloid angiopathy presenting as nonhemorrhagic diffuse encephalopathy: neuropathologic and neuroradiologic manifestations in one case.

A case of cerebral amyloid angiopathy is presented with MR imaging findings of high intense signal on T2-weighted sequences at the level of the white and gray matter of both hemispheres in the absence of neuroradiologic signs of cerebral hemorrhage. The biopsy specimen revealed deposition of amyloid in the walls of the intracranial arterial branches and focal ischemic changes and gliosis in the gray and white matter. We consider this presentation to be very unusual in patients affected by cerebral amyloid angiopathy.

Preoperative embolization of brain and spinal hemangioblastomas.

Large hemangioblastomas can be difficult to resect because of excessive bleeding. We report our experience with two patients whose large hemangioblastomas were embolized preoperatively and were totally resected with minimal blood loss and satisfactory postoperative outcome. Embolizations were carried out within 3 days of surgery, with the patient under general anesthesia, with 150- to 250-microns Contour emboli. A 65-year-old woman with progressive, severe myelopathy from a 4.5 x 2.1 x 1.4 cm intramedullary hemangioblastoma at T4 underwent embolization of the left T2 and T3 intercostal arteries; a 29-year-old man with Lindau's syndrome and posterior fossa hemorrhage from a 3.8 x 1.8 x 1.8 cm right cerebellar hemangioblastoma underwent embolization of the right posterior inferior cerebellar artery, two right anterior inferior cerebellar arteries, and a dural branch of the right vertebral artery. Embolization led to the complete obliteration of the tumoral blush without neurological sequelae. Both lesions were completely resected with a blood loss of 50 to 100 ml, with bleeding occurring mainly from the pseudocapsule of the lesion. Preoperative embolization of hemangioblastomas is a useful and relatively safe procedure that reduces blood loss at the time of surgery and allows complete resection.

Intramedullary dermoid tumor diagnosed with the assistance of magnetic resonance imaging.

Intramedullary dermoid tumors are unusual. Traditional methods of diagnosing spinal tumors have included clinical suspicion, plain roentgenography, myelography, and computed tomography. A case of intramedullary tumor provisionally diagnosed preoperatively by traditional methods and specifically as dermoid tumor with the assistance of magnetic resonance imaging is presented. Diagnosis and treatment of spinal dermoid tumors with an emphasis on magnetic resonance imaging is discussed.

Spontaneous spinal epidural hematoma causing paraplegia: resolution and recovery without surgical decompression.

Spontaneous spinal epidural hematomas are well-recognized but rare entities. The standard treatment for these hematomas has been prompt surgical evacuation. The authors report a case of a 76-year-old man who precipitously became paraplegic secondary to a spontaneous spinal epidural hematoma and then experienced the complete resolution of his neurological deficit and the hematoma. We conclude that conservative (nonoperative) management of spontaneous spinal epidural hematomas may be appropriate in those instances in which there is early and sustained neurological recovery confirmed by radiological resolution of the lesion.

Surgical treatment of intractable epilepsy associated with schizencephaly.

With the advent of magnetic resonance imaging, there has been an increased recognition of schizencephaly during life, especially in epileptic patients. We report our experience with the assessment and treatment of three patients with medically intractable seizures associated with this condition. The three men were aged 24 to 37 years. Two had delayed developmental milestones and hemiparesis or hemiplegia. One had normal development and a normal neurological examination. Seizures began between the ages of 15 and 19 years and lasted for 5 to 22 years before surgery. All had partial simple or generalized seizures with predominant electroencephalographic and electrocorticographic epileptic activity localized to temporal and frontal lobes on the side of the lesion. Neuropsychological assessment indicated widespread dysfunction maximal at the areas of predominant electroencephalographic abnormality. Magnetic resonance imaging demonstrated anterior parasagittal, parietal, and Rolandic cerebral clefts, with ventricular diverticuli, gray matter heterotopia, polymicrogyria, and a true agenesis of the corpus callosum in individual patients. The patients underwent temporal (one patient) and frontotemporal (two patients) lobectomies without additional neurological deficits or neuropsychological deterioration. Postoperative follow-up showed reduction in seizure frequency. We conclude that the surgical treatment of epilepsy is well tolerated in such patients, and their seizures can be alleviated by resection of epileptogenic areas.

Familial cerebral aneurysms: a study of 13 families.

Despite the recent interest in familial cerebral aneurysms, the epidemiology, natural history, pattern of inheritance, screening of asymptomatic relatives, and the search for a biochemical marker remain problematic. To assess these issues, we report the results of our prospective study of 30 patients with 38 aneurysms (27 ruptured) and of the angiographic screening of asymptomatic relatives, all from 13 families seen consecutively since 1986. Women were over-represented (77%), and patients with multiple aneurysms (17%) were under-represented, compared with sporadic cases. Only 16% of the aneurysms were at the anterior communicating artery. Aneurysms occurred at the same or at the mirror site in 10 of 16 siblings (62%) and in 50% of mother-daughter pairs versus 20% for randomly selected, sporadic aneurysm patients. Rupture occurred in the same decade in 10 of 12 siblings (83%) versus the expected 21% for randomly selected, sporadic aneurysms. The average age at rupture was 47.2 years, and 60% of patients with a ruptured aneurysm were 50 years of age or younger. Seventy percent of patients died or were disabled from aneurysmal rupture. Screening of 41 individuals, including 2 dizygous twins, identified 1 aneurysm and 2 infundibula. A specific pattern of inheritance could not be ascertained from the pedigrees. The presence of an aneurysm was not associated with a specific human leukocyte antigen haplotype or antigen, and collagen Type III was qualitatively and quantitatively normal. Until a biological marker is identified, angiographic screening by intra-arterial digital subtraction or magnetic resonance angiography remains the only way to identify patients at risk of harboring a familial cerebral aneurysm.