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Toward the end of the First World War, Harvey Cushing conceived of a National Institute of Neurology (NIN) that would integrate neurology, neurosurgery, psychiatry, and allied disciplines within a single institution. It would first be established for the care of American casualties in an existing military hospital in France, and then relocate to the United States. Cushing was unsuccessful in acquiring funding for this project despite appeals to the army and to the Carnegie and Rockefeller foundations. By 1920 the idea had faded from memory. In 1933 Wilder Penfield was successful in obtaining funding from the Rockefeller Foundation for the creation of the Montreal Neurological Institute (MNI). The MNI's faculty held full-time university appointments and they limited their practice to the institute, where their offices and clinics were housed, and to adjoining research laboratories in neuroanatomy, neurochemistry, neurophysiology, and neuropsychology, as Cushing had envisioned. In this paper the argument is made that although Cushing's plan for the NIN was premature, the success of the MNI proved its feasibility. In addition, the MNI's success in integrating clinical care and research within a single institution was a model for the National Institute of Neurological Diseases and Blindness and drove its first clinical research program.

Dorothy Russell's contributions to neuropathology are pivotal in the evolution of modern neurosurgery. In an era preferential to men in medicine, she entered the second medical school class to include women at the London Hospital Medical College in 1919. In the laboratory of Hubert Turnbull, she met Hugh Cairns, who would become her professional neurosurgeon-neuropathologist partner. In 1929, arriving at McGill's Royal Victoria Hospital in Montreal, where Wilder Penfield and William Cone had just begun a neurosurgical service, Russell elucidated the origin and activity of microglia. Returning to London, Russell continued to work closely with Cairns for many years. Along with J. O. W. Bland, she became the first to culture gliomas and meningiomas. Her work on the effects of and fatality rates associated with head injuries among soldiers during World War II led to the initiation of helmet requirements for motorcyclists. Her textbook, Pathology of the Tumours of the Nervous System, written with Lucien Rubinstein, is considered a landmark text in neurosurgery, neuropathology, and neurooncology. Honored by Penfield and Cone as their first neurosurgery research fellow, Russell was considered a favorite of the Montreal Neurological Institute. Dorothy Russell's extraordinary career elucidating the mysteries of neurosurgical pathology has made an enduring mark on neurosurgery.

Wilder Penfield is well known as the founder of the Montreal Neurological Institute (MNI), the site of his most important contributions to the investigation and treatment of epilepsy and to our understanding of the structure-function relationship of the brain. The seeds of the MNI were sown 6 years before its opening in 1934, when Penfield accepted the position of head of the Subdepartment of Neurosurgery at McGill University's Royal Victoria Hospital (RVH). Penfield took this position because of the facilities made available to him to pursue the neuropathological research that he had undertaken with Pío del Río Hortega in Madrid, and to continue his investigation into the nature and treatment of posttraumatic epilepsy that he began with Otfrid Foerster in Breslau. Penfield and his first neurosurgical research fellows Joseph Evans, Jerzy Choróbski, Nathan Norcross, Theodore Erickson, Isadore Tarlov, and Arne Torkildsen studied the substrate of focal epilepsy, the innervation of cortical arteries, the function of the diencephalon, the microscopic structure of spinal nerve roots, and the ventricular system in health and disease. In his 6 years at the RVH, Penfield and his fellows effected a paradigm shift that saw neurosurgery pass from empirical practice to scientific discipline.

Neurosurgery is predicated on the knowledge of the structure-function relationship of the brain. When the topic is broached in its historiography, it begins with Fritch and Hitzig's report on the localization of motor function in the cortex of the dog and skips rapidly to Wilder Penfield's homunculus. In that gap are found the origins of modern neurosurgery in 3 papers published by Jean-Martin Charcot and Albert Pitres between 1877 and 1879 in which they describe the somatotopic organization of the human motor cortex and draw the first human brain map. Their findings, obtained through the clinicopathological method, gave relevance to David Ferrier's observations in animals. Their work was extensively cited, and their illustrations reproduced by Ferrier in his landmark lecture to the Royal College of Physicians in 1878. It was known to William Macewen, who used localization to guide him in resecting intracranial mass lesions, and to William Osler and John Hughlings Jackson, who were early advocates of intracranial surgery. This paper describes Charcot and Pitres' discovery of the cortical origin of human voluntary movement and its somatotopic organization, and their influence on 19th-century intracranial surgery. It fills a gap in the historiography of cerebral localization and neurosurgery.

Wilder Penfield (1891-1976) is widely regarded as a dominant figure in 20th century neurobiology for his singular contributions to the structure-function relationship of the brain, his discovery of the language function of the supplementary motor area, the discovery (with Herbert Jasper and Brenda Milner) of the anatomy of recall, and his pioneering work in the surgical treatment of focal epilepsy. But another of his significant discoveries has escaped notice: the recognition that focal microgyria can generate epileptic seizures, and that these can be treated surgically. Penfield discussed the case of the patient through which this discovery was made during his Shattuck Lecture to the Massachusetts Medical Society in 1939. As Penfield gave only a fragmentary account of this case, the patient's chart was retrieved from the Montreal Neurological Institute archives, and his operative note and brain map, intraoperative photographs, and the histopathological and cytological examinations of the resected specimen were reviewed. Based on these primary sources, this paper provides a complete, detailed account of the first case in which microgyria was recognized as a cause of focal epilepsy, which was successfully treated surgically.

The vascular hypothesis held that posttraumatic epilepsy results from reflex vasoconstriction of cortical arteries around a cerebral scar. Penfield's initial support and eventual refutation of the vascular hypothesis is the subject of this paper, which is based on a review of his clinical charts, operative and electrocorticographic reports, and brain maps held in the Montreal Neurological Institute archives. Penfield and his collaborators discovered that posttraumatic cortical scars are composed of astro-glial fibers, collagen fibrils, and a neo-vascular plexus that anastomoses with the surrounding cortical arteries. He hypothesized that the contracting scar applied traction to these arteries, which caused epileptic seizures. This was supported by his observations that cortical arteries constrict during an epileptic seizure. Penfield's subsequent investigations led to the discovery that parasympathetic nerves innervate the intracranial arteries, that experimental vasospasm can produce cortical infarction, and that cerebral blood flow (CBF) is coupled to cerebral metabolism. In fact, Penfield found that CBF increases in the epileptogenic zone around a cortical scar, contrary to what the hypothesis had predicted. Despite this, Penfield's investigations shed new light on the dynamics of the cerebral circulation that were not fully understood until decades later.

Harvey Cushing and Wilder Penfield enjoyed a unique professional and personal relationship. Shortly before his retirement from Harvard University in 1933, Cushing sent Penfield 8 sketches that he drew in 1902 and 1903 while he was at Johns Hopkins Hospital. The first series of 3 sketches illustrate the relationship between a cortical hemorrhagic lesion and the motor strip in a patient with focal motor seizures. The second series also comprises 3 sketches. These depict the operative findings in a patient in whom Cushing had electrically stimulated the precentral gyrus, before resecting the cortex subserving motility of the upper extremity to control painful dyskinetic movements. The third series consists of 2 sketches that illustrate the results of stimulation of the motor strip as an aid in the safe resection of an epileptogenic focus in a patient with Jacksonian seizures. These sketches are the subjects of this paper. They add to the relatively sparse record of Cushing's activities in cortical stimulation and in the treatment of functional disorders.

William Howard Feindel (1918-2014) was one of the world's most distinguished neurosurgeons and a brilliant neuroscientist. As the Montreal Neurological Institute's third director, having succeeded Theodore Rasmussen and Wilder Penfield, he proved to be a visionary medical and scientific administrator. His keen interests in epilepsy and brain imaging were enhanced by a passion for medical history. Students and young people invariably gravitated to Dr. Feindel; he was a kind, patient, thoughtful, intelligent, and caring mentor who was never too busy for them. A pioneer in his own right, Dr. Feindel linked our modern neurosurgical world with the legacy of the first generations of important neurosurgeons and neuroscientists.

Object: The authors reviewed their institutional experience with pure low-grade oligodendroglioma (LGO), correlating outcomes with several variables of possible prognostic values., Methods: Sixty-nine patients with WHO-classified LGOs were treated between 1992 and 2006 at the McGill University Health Center. Clinical, pathological, and radiological records were carefully reviewed. Demographic characteristics; the nature and duration of presenting symptoms; baseline neurological function; extent of resection; Karnofsky Performance Scale score; preoperative radiological findings including tumor size, location, and absence/presence of enhancement; and pathological data including chromosome arms 1p/19q codeletion and O-methylguanine-DNA methyltransferase promoter gene methylation status were all compiled. The timing and dose of radio- and/or chemotherapy, date of tumor progression, pathological finding at disease progression, treatment at time of disease progression, and status at the last follow-up were also recorded., Results: The median follow-up period was 6.1 years (range 1.3-16.3 years). The majority (78%) of patients presented with seizures; contrast enhancement was initially seen in 16 patients (25%). All patients had undergone an initial surgical procedure: gross-total resection in 27%, partial resection in 59%, and biopsy only in the remaining 13%. Fifteen patients received adjuvant radiotherapy. Data on O-methylguanine-DNA methyltransferase promoter gene methylation status was available in 47 patients (68%) and in all but 1 patient for 1p/19q status. Survival at 5, 10, and 15 years was 83, 63, and 29%, respectively. Multivariate analysis showed that seizures at presentation and the absence of contrast enhancement were the only independent favorable prognostic factors for survival. The 5-, 10-, and 15-year progression-free survival rates were 46, 7.7, and 0%, respectively., Conclusions: This retrospective review confirms the indolent but progressively fatal nature of LGOs. Contrast enhancement was the most evident single prognostic factor. New treatment strategies are clearly needed in the management of this disease.

Choroid plexus papillomas can metastasize to the subarachnoid space, but extensive metastasis has only been reported when the tumors are malignant. The authors report a case of diffuse, extensive metastasis to the craniospinal leptomeninges from a benign fourth ventricular choroid plexus papilloma in an adult. This 19-year-old woman presented with a 2-year history of headache, blurred vision, diplopia, and ataxia. Magnetic resonance imaging of the brain and spinal cord revealed obstructive hydrocephalus caused by a 4-cm, partially calcified, inhomogeneously enhancing tumor of the fourth ventricle that was displacing the pons, medulla oblongata, and cerebellum. Innumerable cystic lesions of varying size were also seen in the cranial and spinal leptomeninges. Histological examination of the resected fourth ventricular tumor and of a few of the leptomeningeal lesions revealed a benign choroid plexus papilloma and leptomeningeal choroid plexus cysts. This singular case of diffuse and extensive metastasis to the craniospinal leptomeninges from a histologically benign fourth ventricular papilloma adds to the available information about the biological potential of these tumors and expands the differential diagnosis of posterior fossa lesions with subarachnoid metastasis.

Meningeal melanocytomas are rare tumors of the central nervous system that are found almost exclusively in the posterior fossa and spinal cord and whose natural history is poorly defined. In this report, the authors review the clinical presentation, radiological appearance, operative findings, and histological features in two cases of meningeal melanocytoma: one cranial and one spinal. Two women, aged 21 and 30 years, were admitted to the hospital 60 years apart: the first because of progressive paraplegia and the second because of slowly progressive hearing loss. The first patient had an extradural tumor that was treated by laminectomy, subtotal resection, and postoperative radiotherapy in 1936. Her symptoms recurred 16 years later and she underwent reoperation of the residual tumor, which was found to have an intradural component. The authors' patient, who presented 60 years later, underwent plain and enhanced computerized tomography and magnetic resonance imaging that demonstrated a large posterior fossa lesion indicative of either an acoustic neuroma or a meningioma. She underwent posterior fossa decompression but only partial excision of the tumor could be accomplished because vigorous bleeding limited the extent of the resection. Surgery was followed by radiotherapy. The residual tumor enlarged despite these measures and required repeated resection 6 months later. At the second operation the tumor was much less vascular, perhaps reflecting the effects of radiotherapy, and was removed almost entirely. The patient died 6 months later from an anticoagulant-related cerebellar hemorrhage. In both cases the lesions were jet black, and histological examination revealed melanin-containing hypercellular tumors with rare mitotic figures. Meningeal melanocytomas are being diagnosed with increased frequency in parallel with improvements in neuroimaging and clarification of histological features. Clinical presentation of patients with these tumors typically occurs in their fifth decade and women are affected twice as often as men. The posterior fossa lesions can mimic acoustic neuromas and meningiomas in location and radiological appearance; however, the internal auditory canal is normal. In the spine, meningeal melanocytomas present with the clinical features of myeloradiculopathy. Diagnosis is made intraoperatively from the gross, jet-black appearance of the tumor and from histological examination. Vascularity, size, and location may render complete resection unfeasible. Because of the tumor's propensity to recur, radiotherapy has been recommended but its role remains to be elucidated.

Cerebral dysgenesis is a subject of interest because of its relationship to cerebral development and dysfunction and to epilepsy. The authors present a detailed study of a 16-year-old boy who underwent surgery for a severe seizure disorder. This patient had dysgenesis of the right hemisphere, which was composed of a giant central frontoparietal nodular gray matter heterotopia with overlying large islands of cortical dysplasia around a displaced central fissure. Exceptional insight into the function, biochemistry, electrophysiology, and histological structure of this lesion was obtained from neurological studies that revealed complementary information: magnetic resonance (MR) imaging, [18]fluoro-2-deoxy-D-glucose positron emission tomography (PET), functional PET scanning, proton MR spectroscopic (1H-MRS) imaging, intraoperative cortical mapping and electrocorticography, in vitro electrophysiology, and immunocytochemistry. These studies demonstrated compensatory cortical reorganization and showed that large areas of heterotopia and cortical dysplasia in the central area may retain normal motor and sensory function despite strikingly altered cytoarchitectonic organization and neuronal metabolism. Such lesions necessitate appropriate functional imaging studies prior to surgery and cortical mapping to avoid creating neurological deficits. Integrated studies, such as PET, 1H-MRS imaging, cortical mapping, immunocytochemistry, and electrophysiology may provide information on the function of developmental disorders of cerebral organization.

The authors report the coexistence of vascular nevi (hemangiomas and arteriovenous malformations (AVMs) of the skin) with AVMs and venous malformations of the brain in male siblings from two related but nonconsanguineous families of three generations. The proband, his siblings, parents, aunts, uncles, and cousins were examined, underwent magnetic resonance (MR) imaging and MR angiography, and when appropriate, cerebral angiography. A father had vascular nevi and a mother, his sister, had an azygos anterior cerebral artery. No other cutaneous or cerebrovascular malformations were present in the parents. Each of the two families had two boys and one girl, 9 to 18 years of age. All the children had vascular nevi and all of the boys had coexisting cerebrovascular malformations: AVMs in three, and a venous malformation in another. One boy had three cerebral AVMs. Two boys had a cerebral hemorrhage, and one also had focal motor seizures. The skin lesions were not those of the Sturge-Weber-Dimitri, Rendu-Osler-Weber, or Wybum-Mason syndromes. The association of cutaneous and cerebrovascular malformations was seen only in males in these families. but females have also been reported in the literature. The results obtained in these families and three other families reported from Western and Central Europe indicate that the association of cerebral and cutaneous vascular hamartomas constitutes a distinct, hereditary clinicopathological entity with autosomal dominant inheritance and variable penetrance. The clinical manifestations of this syndrome are visible, painful vascular nevi, epilepsy, cerebral hemorrhage, and focal neurological deficits. The preponderance of male patients with the full expression of the syndrome suggests a possible hormonal influence on the expression of the gene.

Spinal angiolipomas are distinct, benign lesions composed of mature lipocytes admixed with abnormal blood vessels. Three new cases of spinal angiolipoma are presented and 34 previously reported cases are analyzed. The 37 total cases (23 females and 14 males) ranged in age from 17 to 73 years (mean 43 years; median 45 years). The mean age of the female patients was older than that for the males (45.0 vs. 41.6 years; p < 0.001, Student's t-test) and most were peri- or postmenopausal. Prior to diagnosis, 97% of the patients had weakness of the lower extremities, 94% had sensory dysfunction, 84% had hyperreflexia and spasticity, 51% had sphincter dysfunction, and 41% had back pain lasting from 1 to 180 months (mean 28 months). Five (22%) of the 23 female patients were pregnant and two had exhibited significant weight gain coincident with the onset of symptoms. The angiolipomas were extradural in 35 patients and intramedullary in two; seven of the extradural lesions infiltrated the surrounding bone. The tumors extended from C-6 to L-4 and had a predilection for the midthoracic region (53% of cases). Plain radiographs were abnormal in 11 (39%) of 28 patients and in all patients with bone infiltration. Myelograms were abnormal in 97% of 32 patients and showed a complete block in 63% of patients. Computerized tomography (CT) and magnetic resonance (MR) imaging revealed the fat-density lesions in all cases studied. There was vascular enhancement in three of five cases with contrast-infused CT and in the one case with gadolinium-infused MR imaging. All patients improved following resection of the epidural lesions and internal decompression of the intramedullary lesions. It is concluded that spinal angiolipomas predominantly affect women. They involve the thoracic (especially the midthoracic) region, and produce symptoms and signs of spinal compression and, in some cases, bone erosion and pathological fractures. Their symptomatology can be exacerbated by pregnancy and weight gain, suggesting that vascular engorgement and the presence of obesity influence their evolution. Their preponderance in older, peri-, or postmenopausal women, and their clinical exacerbation in pregnant women support a role for hormonal influence. Magnetic resonance imaging is the investigation of choice for the diagnosis of these lesions. Surgery is universally successful in relieving symptoms.

Given the widespread use of continuous external ventricular drainage in patients with aneurysmal subarachnoid hemorrhage (SAH), this investigation was undertaken to define the relationship of ventricular drainage to aneurysmal rebleeding. A historical cohort study of 128 patients with confirmed aneurysmal SAH was performed using a multivariate stepwise logistic regression analysis to examine the relationship between aneurysmal rerupture and ventricular drainage, while controlling for important clinical and radiological independent variables. The variables for ventricular drainage selected in the regression analysis were clinical grade, aneurysm size, and presence of hydrocephalus. The rate of rerupture was significantly higher in cases with ventricular drainage (odds ratio 5.31:1, p less than 0.05), poor clinical grade (odds ratio 4.90:1, p less than 0.02), and large aneurysm size (odds ratio 11.25:1, p less than 0.01). The significant effect of ventricular drainage was limited to patients with hydrocephalus. The increased risk of aneurysmal rebleeding in patients undergoing ventricular drainage may result from both: 1) a rise in aneurysmal transmural pressure, since intracranial pressure is lowered by ventricular drainage; and 2) an association between ventricular drainage and a more severely disrupted aneurysm which is more prone to rebleed as part of its natural history. This study found an increased risk of aneurysmal rebleeding among patients undergoing ventricular drainage, particularly in the presence of hydrocephalus.

The authors describe the association between an antero-basal temporal lobe encephalocele and medically intractable temporal lobe epilepsy in three patients treated successfully by surgery. Two men and one woman, aged 26 to 37 years (mean 31 years), had onset of complex automatism and generalized seizures in their second and fourth decades (mean age 22.7 years). They had been epileptic for 6 to 14 years (mean 8.3 years) before surgery. Preoperative electroencephalograms localized ictal epileptic activity to the left mesial temporal lobe in all cases, and neuropsychological testing revealed dominant temporal lobe dysfunction. Magnetic resonance (MR) imaging demonstrated an anteromedial basal temporal encephalocele extending into the pterygopalatine fossa through a bone defect at the base of the greater sphenoid wing in the region of the foramen rotundum and pterygoid process, a discrete center of embryonal chondrification. At surgery, the encephaloceles were found in front of the uncus, and an area of gliosis extended from the encephalocele to the amygdalohippocampal region. All patients have been seizure-free following anterior temporal resection and amygdalohippocampectomy including the encephalocele. These three cases delineate a condition of disordered embryogenesis wherein a developmental anterobasal temporal encephalocele acts as the substrate for temporal lobe epilepsy. This lesion may be diagnosed preoperatively with MR imaging and should be considered in the differential diagnosis of late-onset temporal lobe epilepsy.

A case is presented which represents the first instance of the use of functional positron emission tomography (PET) scanning to precisely localize a structural brain lesion to the precentral gyrus, and the first validation of functional PET scanning by intraoperative cortical mapping. The lesion was a 3-cm arteriovenous malformation (AVM) that had produced a generalized seizure in an otherwise asymptomatic young woman. A first, resting H2(15)O PET scan identified the AVM. A second PET scan, performed during vibrotactile stimulation of the contralateral hand, identified the somatosensory area of the hand region and localized the AVM to that part of the precentral gyrus immediately in front of it. This relationship and localization were confirmed by cortical mapping at the time of craniotomy under local anesthesia. Functional PET scanning may prove to be useful to localize cortical lesions precisely and to help in determining preoperatively the best form of treatment for lesions, especially AVM's, in functionally important cortex.

The use of intracerebroventricular bethanechol chloride infusion in patients with Alzheimer's disease was first reported in 1984. An initial trial in four patients demonstrated the feasibility of this approach for cholinergic drug delivery to the brain, but objective improvement in cognitive function was not documented. A collaborative placebo-controlled double-blind crossover study has now been carried out in 49 patients with biopsy-documented Alzheimer's disease. The results demonstrate a statistical improvement in Mini-Mental State scores and significantly slower performance on Trails A testing during drug infusion. Other neuropsychological test scores were not similarly affected. The degree of improvement was not sufficient to justify further treatment of Alzheimer's disease patients by intracerebroventricular infusion of bethanechol chloride. The drug delivery system used in the study was well tolerated, with two irreversible complications in more than 50,000 patient days.

Thirty-four of 87 consecutive patients with subarachnoid hemorrhage from a cerebral aneurysm had a premonitory minor leak. There were 12 men and 22 women, aged 25 to 73 years (mean 44.4 years). Twenty-two had a small and 12 had a large aneurysm located on the internal carotid artery (17 cases), anterior communicating artery (10 cases), middle cerebral artery (five cases), and pericallosal artery (two cases). Fifty-two percent of patients with a minor leak from an internal carotid artery aneurysm had ipsilateral, hemicranial, hemifacial, or periorbital pain. Half of the patients initially saw a physician, but in no case was the correct diagnosis made. Twenty-five patients had a major rupture within 24 hours to 4 weeks after findings suggesting a minor leak, with a mortality rate of 53%. Nine other patients were diagnosed by lumbar puncture or computerized tomography (CT) scanning after initial misdiagnosis and were operated on, without mortality, before a major rupture could occur. The CT scans were negative in 55% of patients with a minor leak, but lumbar puncture, when performed, was always positive. A minor leak prior to major aneurysmal rupture is a common occurrence and, if unrecognized, is associated with a high mortality. Computerized tomography scanning is unreliable in diagnosing this event, and lumbar puncture is the examination of choice once intracranial hypertension has been ruled out.

Computerized tomography (CT) scans of 54 patients with an arteriovenous malformation (AVM) of the brain were reviewed. The 31 males and 23 females (mean age: 33 years) were classified according to clinical presentation: 1) intracranial hemorrhage (30 patients); 2) seizure disorder (19 patients); and 3) other neurological disturbance (five patients). A brain hematoma was identified in all of the patients in the hemorrhage group have a CT scan within 1 week of the bleed. Extension of hemorrhage into the ventricular system as seen in eight cases was invariably accompanied by severe neurological dysfunction. A high-density lesion without associated mass effect was found in 48% of patients presenting with a seizure disorder. Dilatation of the ipsilateral lateral ventricle, a common finding in this group of patients, was thought to indicate an atrophic process. Evidence of discrete brain infarction was unusual. Intravenous infusion with Hypaque provided additional information in 31 of the 35 patients so studied. Demonstration of prominent or enlarged feeding arteries and/or draining veins occurred in 20% of patients with large malformations. Six cases of angiographically occult AVM's were found. A correlation of the CT scan with clinical, angiographic, and histological findings is presented.

It has been suggested that a deficiency in the expression of type III collagen may play a role in the pathogenesis of cerebral aneurysms. To test this hypothesis in cases of familial cerebral aneurysms, fibroblast cell cultures were established and the expression of collagen types I and III was studied in a patient with three cerebral aneurysms whose mother and sister also had cerebral aneurysms. Cultured skin fibroblasts were labeled with tritiated proline. The collagens and procollagens were precipitated and run on sodium dodecyl sulfate-polyacrylamide gel electrophoresis after reduction to analyze procollagen chains. Control cell lines were analyzed simultaneously. Quantitation of the ratios of type III to type I procollagen synthesis was achieved by integration of the intensities of the pro-alpha 1(III), pro-alpha 1(I), and pro-alpha 2(I) bands on fluorograms of electrophoretic gels of medium proteins. There was no difference in type I and III procollagen levels observed between the cells from the aneurysm patient and those from the control cell lines. These data do not support the hypothesis that familial cerebral aneurysms are caused by a deficiency of type III collagen.

Pre- and postoperative positron emission tomography (PET) was performed in six patients undergoing extracranial to intracranial bypass procedures for the treatment of symptomatic extracranial carotid occlusion. The six patients were all men, aged 52 to 68 years. Their symptoms included transient ischemic attacks (five cases), amaurosis fugax (two cases), and completed stroke with good recovery (one case). Positron emission tomography was performed within 4 weeks prior to surgery and between 3 to 6 months postoperatively, using oxygen-15-labeled CO, O2, and CO2 and fluorine-18-labeled fluorodeoxyglucose. Cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral metabolic rates for oxygen and glucose (CMRO2 and CMRGlu), and the oxygen extraction fraction (OEF) were measured in both hemispheres. Preoperatively, compared to five elderly control subjects, patients had increased CBV, a decreased CBF/CBV ratio, and decreased CMRO2, indicating reduced cerebral perfusion pressure and depressed oxygen metabolism. The CBF was decreased in only one patient who had bilateral carotid occlusions; the OEF, CMRGlu, and CMRO2/CMRGlu and CMRGlu/CBF ratios were not significantly different from control measurements. All bypasses were patent and all patients were asymptomatic following surgery. Postoperative PET revealed decreased CBV and an increased CBF/CBV ratio, indicating improved hemodynamic function and oxygen hypometabolism. This was associated with increased CMRO2 in two patients in whom the postoperative OEF was also increased. The CMRGlu and CMRGlu/CBF ratio were increased in five patients. Changes in CBF and the CMRO2/CMRGlu ratio were variable. One patient with preoperative progressive mental deterioration, documented by serial neuropsychological testing and decreasing CBF and CMRO2, had improved postoperative CBF and CMRO2 concomitant with improved neuropsychological functioning. It is concluded that symptomatic carotid occlusion is associated with altered hemodynamic function and oxygen hypometabolism. Cerebral revascularization results in decreased CBV, indicating improved hemodynamic reserve, but does not consistently improve oxygen metabolism.

The authors report seven individuals from two families, all of whom had aneurysmal subarachnoid hemorrhage. These cases and all reported cases of familial aneurysms (243 aneurysms in 177 patients from 74 families) were submitted to computer-aided multivariate analysis to determine if the aneurysms or the patients who harbor them differ from sporadic aneurysm cases. Familial aneurysms rupture at a smaller size (mean diameter 10.5 mm), and when the patient is younger (mean age 42.3 years and decennial age at peak incidence 40 to 49 years). There is a similar sex distribution (male to female ratio 48:52), a similar incidence of multiple aneurysms (21.5%), and a similar predominance of females over males with multiple aneurysms (2.2:1). Anterior communicating artery aneurysms occur less often in familial cases (19%) than in sporadic cases. In sibling pairs the aneurysms occur at the same or at mirror sites, and rupture within the same decade twice as frequently as randomly selected nonfamilial aneurysm patient pairs. The occurrence of aneurysms at identical and mirror sites is more frequent in familial cases and appears to be a function of the degree of kinship between affected individuals. These observations suggest a genetic basis for the pathogenesis of familial intracranial aneurysms.

Forty-six neonates with intracranial hemorrhage were classified into three groups on the basis of the major computerized tomography (CT) scan findings: Group I consisted of 24 cases of subarachnoid hemorrhage, Group II 20 cases of intracerebral and/or intraventricular hemorrhage, and Group III two cases of subdural hemorrhage. The initial scans in Group I showed blood in the interhemispheric fissure and the supratentorial recess. Sixty percent had an associated hypodensity in the frontal and/or parietal areas, thought to be an indication of ischemia. Changes in the configuration of the ventricular system were infrequent. Initial scans in Group II showed hematomas as follows: one in the brain stem, five in the basal ganglia, 10 in the temporal lobes, and 11 in the ventricles. In 70% of these cases, changes in the configuration of the ventricular system were seen, including compression of a lateral ventricle by mass effect, ventricular dilatation with blood, and obstructive hydrocephalus. Subarachnoid blood was an associated finding in 55% of cases, and focal and diffuse cerebral edema in 40%. Scans in both Group III patients initially showed a mass effect from a subdural clot. In all, 30 patients had one or more follow-up CT scans, and 13 of these were scanned at regular intervals. None of the Group I patients developed hydrocephalus, but 85% of Group II patients with intraventricular blood extending from an intracerebral hemorrhage had this complication. A seizure disorder occurred in 31% of Group I patients and 20% of Group II patients, where it was seen exclusively in those with an intralobar hematoma. A major motor disturbance occurred in 16% of patients; their Ct scans showed evidence of brain destruction involving enlargement of a lateral ventricle, porencephaly, or focal atrophy. Computerized tomography is a useful adjunct to the diagnosis, management, and follow-up study of neonatal intracranial hemorrhage, and correlates well with the clinical findings.