1/34. Temporary occlusion of middle cerebral artery by macroembolism in carotid surgery.Two patients are presented who during carotid endarterectomy (CEA) temporarily showed an obstruction of the middle cerebral artery (MCA) mainstem by a macroembolus resulting in cerebral ischaemia. Both cases are unusual examples of CEA and selected from a cohort of more than 1,500 operations. During surgery with general anaesthesia, brain function was monitored with computerized electroencephalography (EEG) and transcranial Doppler (TCD) ultrasonography. The simultaneous use of EEG and TCD monitoring allowed us to witness the development of intraoperative cerebral ischaemia and to relate these events to a temporary occlusion of the MCA mainstem by a macroembolus. This is the first life report that describes obstruction of a cerebral artery by arterial embolism resulting in cerebral ischaemia.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
2/34. Faces call for attention: evidence from patients with visual extinction.Three patients with left spatial neglect and visual extinction from right brain damage were studied to determine whether faces are privileged in summoning attention. In a first experiment, either a face, a name, or a meaningless shape were briefly presented in the right, left or both visual hemifields. On bilateral trials, all patients extinguished a left-side face much less often than a left-side name or a left-side shape. Conversely, they extinguished a left-side shape more often when it was accompanied by a right-side face rather than a right-side name. In a second experiment, either a face or a scrambled face could appear in the right, left or both hemifields. Again, on bilateral trials, a left-side face was less likely to be missed than a scrambled one. These results suggest an advantage of faces in capturing attention and overcoming extinction, which may be related to their special biological and social value, or to the very efficient and automatic operation of specific perceptual processses that extract facial organization in extrastriate visual areas. These findings also demonstrate that the distribution of spatial attention and extinction can be modulated by the relevance of visual stimuli. This implies that substantial analysis and categorization may take place in the visual system before information from the contralesional field is selected for, or excluded from, attentive vision.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
3/34. Clinical experience with cerebral oximetry in stroke and cardiac arrest.OBJECTIVE: To address the ability and reliability of the INVOS 3100A (Somanetics, Troy, MI) cerebral oximeter to detect cerebral desaturation in patients and the interpretation of cerebral oximetry measurements using the INVOS 3100A in stroke and cardiac arrest. DESIGN: case reports of two patients. SETTING: Neurologic intensive care Unit of a University Hospital. patients: Two patients suffering occlusive strokes of the middle cerebral artery. One later suffered a cardiac arrest. RESULTS: The first case, a patient who suffered cardiac arrest while undergoing continuous cerebral oximetry, clearly demonstrated the ability of the INVOS 3100A to detect rapid tissue vascular oxyhemoglobin desaturation in the brain during circulatory arrest. In the second case, oximetry readings were obtained in a patient with a right internal carotid artery occlusion and an infarct in the middle cerebral artery territory. The circulation of the anterior cerebral artery (ACA) territory was intact. Stable xenon-computed tomography of local cerebral blood flow showed no perfusion in the infarct, and oximetry readings were between 60 and 65. In the border zone between the middle cerebral artery and the ACA, readings of 35 to 40 were obtained, and over the ACA territory, the readings were in the 60s. CONCLUSIONS: oximetry by near infrared spectroscopy reflects the balance between regional oxygen supply and demand. In dead or infarcted nonmetabolizing brain, saturation may be near normal because of sequestered cerebral venous blood in capillaries and venous capacitance vessels and contribution from overlying tissue. In regionally or globally ischemic, but metabolizing brain, saturation decreases because oxygen supply is insufficient to meet metabolic demand. These observations are supported by previously reported "normal" readings in unperfused or dead brains.- - - - - - - - - - ranking = 4keywords = brain (Clic here for more details about this article) |
4/34. diffusion-weighted MRI of middle cerebral artery stroke in a newborn.diffusion-weighted MRI of the brain is becoming clinically available as a tool to investigate cerebral ischaemia. We report a newborn girl presenting with seizures in whom diffusion-weighted MRI showed a large hyperintensity in the area perfused by the left middle cerebral artery. Short-term neurological follow-up before discharge was uneventful and the patient was discharged without sequelae. On follow-up clinical examination, right-sided spastic signs were noted which disappeared with time.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
5/34. Cerebral blood flow velocity in two patients with neonatal cerebral infarction.Cerebral blood flow velocity was measured in the middle cerebral artery of two patients who exhibited unilateral neonatal cerebral infarction during the neonatal period. Doppler studies demonstrated increases in cerebral blood flow velocity but decreases in the resistance index on the affected side of the middle cerebral artery in the neonate who developed hemiplegia with cystic encephalomalacia, although the neonate with normal neurologic outcome exhibited symmetric cerebral blood flow velocity and resistance index. The asymmetry in cerebral blood flow velocity measurements of both middle cerebral arteries may be useful to evaluate the severity of brain damage and predict the neurodevelopmental prognosis of unilateral neonatal cerebral infarction.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
6/34. Internal carotid artery thrombus: an underdiagnosed source of brain emboli in neonates?We report a full-term neonate with a left middle cerebral artery infarct, narrowing of the internal carotid artery detected by magnetic resonance angiography and B-mode ultrasonography, and a large thrombus at the origin of the internal carotid artery detected by B-mode ultrasonography. Internal carotid arterial thrombus is seldom considered the source of middle cerebral arterial embolus in neonates. We suggest that B-mode ultrasonography of the carotid artery be included in the diagnostic evaluation of middle cerebral artery infarcts in neonates.- - - - - - - - - - ranking = 4keywords = brain (Clic here for more details about this article) |
7/34. stroke in a young man with fibromuscular dysplasia of the cranial vessels with anticardiolipin antibodies: a case report.A case of fibromuscular dysplasia (FMD), presenting with a non-hemorrhagic infarct is reported. Positivity of anticardiolipin antibodies suggested an immune response. A 40-year-old man presented with sudden onset of stroke, preceded by similar ischemic attacks. Computed tomography (CT) of the brain showed a recent non-hemorrhagic infarct in the left middle cerebral artery (MCA) territory and an old right MCA territory infarct. serum was positive for anticardiolipin antibodies. These above findings were confirmed at autopsy. A portion of the internal carotid artery and the middle cerebral arteries on both sides revealed features of FMD, with thrombosis. This case suggests an immune mechanism for FMD, hitherto unobserved in the cerebral circulation.- - - - - - - - - - ranking = 1keywords = brain (Clic here for more details about this article) |
8/34. Postvaricella angiopathy: report of a case with pathologic correlation.Varicella is a common childhood illness, and central nervous system complications occur frequently. Delayed angiopathy has been described, although there are few reports of clinicopathologic correlation. A previously well 4-year-old male is presented. He suffered varicella 2 months before presentation with extensive right middle cerebral artery (MCA) territory infarction. cerebral angiography demonstrated an isolated 89% stenosis of the right proximal MCA. He developed cerebral edema refractory to medical treatment and progressed to transtentorial herniation. Right frontal temporoparietal craniotomies were performed with evacuation of infarcted brain tissue. Pathologic studies revealed small vessel vasculitis with lymphocytic infiltration of the vessel wall. Areas of demyelination were present within the white matter. polymerase chain reaction for varicella was negative on brain tissue. Postvaricella angiopathy, although an uncommon complication, may affect both small and large blood vessels, with catastrophic results.- - - - - - - - - - ranking = 2keywords = brain (Clic here for more details about this article) |
9/34. Crossed nonaphasia in a dextral with left hemispheric lesions: a functional magnetic resonance imaging study of mirrored brain organization.BACKGROUND: General conclusions concerning mechanisms of cerebral lateralization may be learned from the investigation of functional brain organization in patients with anomalous lateralization. CASE DESCRIPTION: The functional organization of language, attention, and motor performance was investigated in a 42-year-old patient with crossed nonaphasia by means of functional MRI. The strongly right-handed man experienced a left middle cerebral artery infarction documented by MRI without exhibition of aphasia. However, the left hemispheric stroke was accompanied by visuospatial impairment, right-sided slight sensory and motor paresis, and right homonymous hemianopia. No history of familial sinistrality or prior neurological illness was present. Functional MR language mapping revealed strong right hemispheric activation in inferior frontal and superior temporal cortices. Finger tapping with the right hand recruited ipsilateral premotor and motor areas as well as supplementary motor cortex. A Stroop task, usually strongly associated with left-sided inferior frontal activation in dextrals, resulted in strong right hemispheric frontal activation. CONCLUSIONS: From our data there is clear evidence that different modalities, such as language perception and production, attention, and motor performance, are processed exclusively by 1 hemisphere when atypical cerebral dominance is present.- - - - - - - - - - ranking = 5keywords = brain (Clic here for more details about this article) |
10/34. Neurometabolic changes during treatment with moderate hypothermia in a patient suffering from severe middle cerebral artery infarction.microdialysis is a means of measuring neurochemical changes in the extracellular space and has been applied in acute brain trauma, subarachnoid hemorrhage and stroke patients. In this study, we monitored neurochemical changes in the extracellular space using microdialysis in a patient with left-sided hemispheric infarction treated with moderate hypothermia (33 degrees C). microdialysis probes were obtained from the infarcted and noninfarcted hemisphere during hypothermia and rewarming. Concentrations of extracellular substances in the infarcted hemisphere (glutamate, glycerine, lactate/pyruvate) decreased with hypothermia and remained stable (glutamate) or increased (glycerine, lactate/pyruvate) during rewarming. Concentrations of these substances in the noninfarcted hemisphere remained at normal levels. microdialysis monitoring of therapeutic hypothermia in severe hemispheric infarction might be a useful additional monitoring tool to assess the status of the brain and to predict further deterioration.- - - - - - - - - - ranking = 2keywords = brain (Clic here for more details about this article) |
| | Next -> |