Cases reported "Brain Ischemia"

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11/122. magnetic resonance imaging detection of microbleeds before thrombolysis: an emerging application.

    BACKGROUND: Hemorrhagic transformation (HT) is a major complication of thrombolytic treatment for acute ischemic stroke. Although a history of prior intracerebral hemorrhage diagnosed by head CT is a contraindication to thrombolysis, there are no guidelines or data regarding evidence of prior asymptomatic microbleeds visualized with T2*-weighted magnetic resonance imaging (MRI). methods: Pretreatment T2*-weighted MRI sequences were retrospectively analyzed in all patients receiving intra-arterial thrombolytic therapy and undergoing a pretreatment MRI at our institution. The frequency and location of prior microbleeds was determined and compared with the frequency and location of secondary HT after therapy. RESULTS: Five of 41 patients undergoing MRI before receiving intra-arterial thrombolytic therapy demonstrated evidence of prior microbleeds on the pretreatment MRI studies. Major symptomatic hemorrhage occurred in 1 of 5 patients with microbleeds compared with 4 of 36 patients without. Only 1 patient in the entire 41-patient cohort experienced any HT outside the acute ischemic field. In this patient, the symptomatic hemorrhage occurred directly at the site of a prior microbleed, contralateral to the acute ischemic event. CONCLUSIONS: Old silent microbleeds, visualized with T2*-weighted MRI sequences, may be a marker of increased risk of HT in patients receiving thrombolytic therapy for acute ischemic stroke. Pretreatment screening of thrombolytic candidates with these MRI sequences may be useful in the future to identify these patients.
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12/122. Altered hemodynamic responses in patients after subcortical stroke measured by functional MRI.

    BACKGROUND AND PURPOSE: blood oxygenation level-dependent (BOLD) functional MRI (fMRI) is a promising method for defining brain recovery after stroke quantitatively. Applications thus far have assumed that the BOLD hemodynamic response in patients after stroke is identical to that in healthy controls. However, because of local vascular compromise or more diffuse vascular disease predisposing to infarction, this assumption may not be justified after stroke. We sought to test whether patients who have suffered a lacunar stroke show BOLD fMRI response characteristics identical to those of healthy controls. methods: We measured the BOLD fMRI signal time course in the sensorimotor cortex contralateral to the affected hand with finger- or hand-tapping tasks for minimally or mildly impaired right-handed patients (n=12) after lacunar strokes causing limb weakness and for healthy controls (n=20). RESULTS: With a right-handed sequential finger-tapping task, the rate of rise and maximum increase of the BOLD signal in the contralateral sensorimotor cortex were > 30% lower (P< or =0.01) in the stroke patients. Similar relative decreases were found for the same task performed with the left hand. These changes were found in patients both in the hemisphere affected by stroke and in the unaffected hemisphere, suggesting that the BOLD fMRI time course differences observed arise from a diffuse functional pathology. The difference between patients and controls is not a result of age alone, since differences were not found between the younger (n=10; aged 22 to 38 years) and the older (n=10; aged 56 to 83 years) healthy controls. The effect also does not seem to be dependent on the specific hand movement task used. CONCLUSIONS: The magnitude of the BOLD fMRI response can be reduced in stroke patients even if infarcts do not involve the cortex. This may be a consequence of the stroke, but the observation that the BOLD signal time course is similar in the affected and unaffected hemispheres suggests that it also could result from preexisting pathophysiological changes in the cerebral microvasculature.
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keywords = cortex
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13/122. Acute cortical blindness complicating pre-eclampsia.

    Cortical blindness in pre-eclampsia due petechial hemorrhages, ischemia, focal edema and infarction of the occipital cortex, is mostly reversible.
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14/122. Complex hallucinations following occipital lobe damage.

    Visual hallucinations may accompany many neurological and psychiatric disorders. A common localization principle is that lesions to the early sensory cortices lead to elementary hallucinations, whereas complex perceptual experiences are related to the pathology of higher-level cortical regions. We report the case of a patient who experienced complex, non-stereotyped, multimodal (visual and somatosensory) hallucinations following an acute ischaemic vascular lesion in the right medial occipital lobe. This illustrates that the phenomenology of hallucinations not necessarily reflects the exact localization of cerebral pathology. Instead, the damaged area may serve as a focus of an abnormally activated neuronal network.
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15/122. A light and electron microscopic study of oedematous human cerebral cortex in two patients with post-traumatic seizures.

    PRIMARY OBJECTIVE: brain cortical biopsies of two patients with clinical diagnosis of complicated brain trauma who had seizures, were studied by means of light and electron microscopes in order to correlate structural alterations with seizure activity. methods AND PROCEDURES: biopsy samples of left frontal cortex and right parietal cortex were processed by current techniques for light and transmission electron microscopy. RESULTS: The tissue showed severe vasogenic oedema with perivascular and intraparenchymatous haemorrhages. At the capillary wall, increased vesicular and vacuolar transendothelial transport, open endothelial junctions, thickened basement membrane and swollen perivascular astrocytic end-feet were observed. Some pyramidal and non-pyramidal nerve cells appeared dense and shrunken and others exhibited marked intraneuronal enlargement of membrane compartment. The myelinated axons displayed signs of degeneration and a process of axonal sprouting. Numerous swollen asymmetrical axo-dendritic synaptic contacts were observed in the neuropil, which exhibited mostly closely aggregated spheroidal synaptic vesicles toward the presynaptic membrane and numerous exocytotic vesicles sites. The perisynaptic astrocytic ensheathment appeared retracted or absent, whereas the extracellular space appeared notably dilated. Synaptic disassembly was also observed. CONCLUSION: The findings demonstrate, in two patients with post-traumatic seizure activity, brain barrier dysfunction, vasogenic oedema, anoxic-ischaemic neurons, axonal sprouting, numerous altered excitatory synapses and synaptic disassembly. Some considerations on clinical and research applications are discussed.
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keywords = cortex
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16/122. Pseudomigraine with prolonged aphasia in a child with cranial irradiation for medulloblastoma.

    We report a 12-year-old child with episodes of migraine-like headaches with visual and motor auras a year after the surgical resection and radiation therapy for medulloblastoma The patient presented with an episode of headache, prolonged aphasia, right hemiparesis, status epilepticus, and salt wasting. There was no evidence of a structural lesion. The neurologic deficits resolved over a period of 6 weeks. Because of the progressive deterioration in neurologic deficits, the patient underwent an extensive battery of laboratory tests and multiple neuroimages, all of which were normal. The unusually prolonged neurologic deficit in this patient without demonstrable structural lesions and his eventual complete recovery were most likely caused by ischemia in the left hemisphere secondary to vasospasm. This presentation mimics migraine headache. Evidence suggesting that this represents a long-term complication of treatment of children with central nervous system neoplasia is presented.
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17/122. Deficits of motor intention following parietal lesions.

    patients with lesions to the right parietal lobe were tested on their ability to reach to targets, or to respond verbally to targets. The targets occurred at the same two spatial locations--to the left and right of the patient--with the task being cued by the color of the target. patients were able to perform both tasks separately rapidly and without error. However, when the two tasks were interleaved, they had difficulty making a response in the left (contralesional) field when this was different to a response that they had just made. These results suggest that lesions to the parietal cortex may cause a deficit in the coding for motor intention, as well as attention in the contralesional field.
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keywords = cortex
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18/122. Intra-operative monitoring of brain tissue O2 (PtiO2) during aneurysm surgery.

    BACKGROUND: Regional cerebral blood flow may be compromised during aneurysm surgery. This may occur during vessel occlusion by temporary cliping or result from the malposition of an aneurysm clip. In this report we monitored intra-operatively the brain tissue oxygen concentration (PtiO2) to visualize regional ischaemic events. METHOD: During surgery of 10 intracranial aneurysms, monitoring of PtiO2 was performed using a polarographic microcatheter (Licox, GMS-Kiel-germany), which was placed in the vascular territory of the artery harboring the aneurysm. FINDINGS: No complications were observed after implantation of Licox electrodes. In 6 patients PtiO2 decreased during transient clipping. In two patients PtiO2 decreased below 2 mmHg without morphological or clinical signs cerebral ischemia. In four patients, without incidence during surgery, only minor oscillations were observed. CONCLUSION: Intra-operative monitoring of PtiO2 is a complimentary procedure to monitor cerebral perfusion and detect episodes of ischaemia. Given the rapid detection of these events, therapeutic intervention may be initiated before irreversible neuronal damage occurs.
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19/122. face context interferes with local part processing in a prosopagnosic patient.

    We investigated the role of local and global information on perceptual encoding of faces in patient HJA, who shows prosopagnosia and visual agnosia following occipito-temporal damage. HJA and an age-matched control were tested in a simultaneous matching task which focused on detection of local changes in faces: the inversion of central parts (eyes and mouth) relative to their context (as in the Thatcher illusion). Same-different judgements were made to normal, "that cherised" and mixed type face pairs. Whole faces (Experiment 1), or face parts (Experiment 2), were presented in upright and inverted orientations. Compared to the control, HJA was severely impaired at matching whole faces, but he improved dramatically when face parts were presented in isolation. This suggests an inhibitory influence of face context on HJAs processing of local parts and a relatively intact ability to process part-based information from a face (when context cannot interfere). face inversion did not affect HJAs performance. A control experiment (Experiment 3) with non-face stimuli (houses) suggested that the inhibitory influence of context on HJAs performance was restricted to faces. These results indicate that contextual information in a face can have an adverse influence on the processing of local part-based information in prosopagnosia.
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keywords = visual
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20/122. Hemiballism with insular infarction as first manifestation of Takayasu's arteritis in association with chronic hepatitis B.

    BACKGROUND: Takayasu's arteritis is a chronic inflammatory idiopathic disease involving large arteries like the aorta and its primary branches. Cell-mediated autoimmunity leading to vascular injury has been suspected in its pathogenesis although the antigen inducing the process remains unknown. CASE REPORT: A 50-year-old male patient suffered from acute hemiballism. neuroimaging showed an infarction of right temporal insular cortex. Neurosonology and MR-angiography revealed bilateral long-distant subtotal stenosis of the common carotid artery and left-sided occlusion of the subclavian artery. Positive hepatitis B serology with active viral replication was found. In the absence of other vasculitis or inflammation markers, Takayasu's arteritis was diagnosed and steroid therapy was started. CONCLUSIONS: Unilateral insular lesions may lead to transient hemiballistic movements which could be the result of decreased inhibitory output of the insula to basal ganglia. The hepatitis b virus possibly contains a surface antigen inducing a specific cellular immune response leading to Takayasu's arteritis.
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keywords = cortex
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