Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied cerebellar metabolism in 118 subjects including young and elderly controls and patients suffering from stroke, supratentorial brain tumor and Alzheimer's disease using fluorine-18 fluorodeoxyglucose ([18F]FDG) and position emission tomography (PET). Alzheimer's disease and normal aging did not alter mean cerebellar metabolism. In stroke and tumor mean cerebellar metabolism was lower in the hemisphere contralateral to the supratentorial lesion. In tumor bilaterally significant reductions in absolute cerebellar metabolism also were noted, unlike stroke. Primary sensory stimulation did not alter absolute or relative cerebellar metabolism. These results show that absolute and relative values for cerebellar metabolism vary depending on the process under study. Thus analysis schemes employing normalization of regional metabolic data to cerebellar values may be subject to error.
 ...
PMID:Cerebellar glucose consumption in normal and pathologic states using fluorine-FDG and PET. 349 90

Lumped and transfer rate constants in ischemic brain tissue must be measured to estimate accurately cerebral glucose utilization by the deoxyglucose method. We studied the bilateral middle cerebral artery occlusion model in 17 cats, 5 with a 1-hour occlusion, 5 with a 4-hour occlusion, and 7 with a sham operation. The time course of cerebral tissue radioactivity (Ci*(t)) was monitored by external coincidence counting during a programmed infusion of [18F]-2-deoxy-2-fluoro-d-glucose (18F-2-FDG). Arterial plasma concentration (Cp*(t)) of the tracer was kept constant during the first 45 minutes. Rate constants were estimated from Ci*(t) and Cp*(t) by a nonlinear least-squares fitting routine. The lumped constant was estimated from the fit of the ratio of extraction fractions of glucose and 18F-2-FDG by nonweighted, nonlinear least-squares fitting. In the 4-hour-occlusion model, the transfer constant k1* was 23% lower, k3* 39% lower, and the lumped constant 78% higher than in the sham-operated animals. In the 1-hour-occlusion model, k3* was 26% lower than in the sham-operated animals but the lumped constant was not significantly different. The rate of glucose utilization was significantly different in the 4-hour-occlusion model compared to the sham-operated animals (48% decrease, p less than 0.05) but was not significantly different in the 1-hour-occlusion model.
Stroke
PMID:Simultaneous in vivo measurement of lumped constant and rate constants in experimental cerebral ischemia using F-18 FDG. 381 Jul 49

A 2-[18F]-Fluoro-2-Deoxy-D-Glucose ([18F]FDG) and positron emission tomography (PET) study was performed in the acute and chronic phase of stroke in one patient with unilateral neglect due to a right hemispheric lesion. In the acute phase, severe neglect, as well as hypometabolism in both the right and in the left unaffected cerebral hemisphere, was demonstrated. At follow-up evaluation the patient showed an almost complete recovery from unilateral neglect. This was associated with a return of left hemisphere metabolism to normal values and partial metabolic recovery in the right hemisphere, where frontal and parietal areas remained functionally impaired. Another patient with an extensive right cerebral ischaemic lesion on CT and severe unilateral neglect was studied by PET in chronic phase. A severe metabolic depression in the left unaffected hemisphere and in the right cerebral areas spared by the lesion, was found. These data suggest that the remission of unilateral neglect might be associated to a functional metabolic recovery in both the undamaged left hemisphere and the unaffected regions of the right hemisphere.
 ...
PMID:Left and right hemisphere contribution to recovery from neglect after right hemisphere damage--an [18F]FDG pet study of two cases. 845 81

Two cases of aphasia after right hemispheric stroke in right handed patients are described. The first patient had a severe mixed transcortical aphasia, apraxia and neglect after a lesion involving the right lenticular nucleus and periventricular white matter; aphasia was still present after three months. The second patient had a mild, transient fluent aphasia after a small right hemispheric periventricular lesion. Studies with [18F]FDG and positron emission tomography (PET) showed functional depression extending to the structurally unaffected left hemisphere in both patients in the acute stage. After three months, in the patient with persistent aphasia, metabolism was still reduced in the right hemisphere, with some recovery of hypometabolism on the left, while metabolic values had returned to normal in the patient with full language recovery. A close parallelism between glucose metabolism and clinical course in crossed aphasia is shown, as well as the presence of a functional involvement of the structurally unaffected left hemisphere in the acute stage.
 ...
PMID:Crossed aphasia: a PET follow up study of two cases. 820 63

The neural correlates of recovery from aphasia are largely unknown. Several different sources of evidence, from clinical studies to neurophysiological investigations, have suggested a contribution of the contralateral, undamaged hemisphere in recovery from aphasia. Eight patients with unilateral left hemispheric stroke were submitted to a standard language examination and to a [18F]FDG PET study in the recent phase after stroke (within 2 weeks) and 6 months later. All patients had a substantial recovery of specific aspects of language functions at the follow-up. Analysis of regional glucose metabolism showed hypometabolism in structurally unaffected regions both in the left and in the right hemisphere (diaschisis), in the acute stage. Glucose metabolism increased significantly on both sides in all patients at the second PET study. Regional analysis showed significant positive correlations between changes in metabolic values in several cortical and subcortical regions in the right hemisphere and changes in language performance at follow-up. The present findings show that an extensive, bihemispheric depression of metabolism is found in the acute stage after stroke in aphasic patients. Language recovery in the first months after aphasia onset is associated with regression of functional depression (diaschisis) in structurally unaffected regions, in particular in the right hemisphere.
 ...
PMID:A PET follow-up study of recovery after stroke in acute aphasics. 899 98

The authors recently developed a primate thromboembolic stroke model. To characterize the primate model, the authors determined serial changes in cerebral blood flow (CBF) and the relation between CBF and cerebral metabolic rate of glucose (CMRglc) using high-resolution positron emission tomography. Thromboembolic stroke was produced in male cynomolgus monkeys (n = 4). Acute obstruction of the left middle cerebral artery was achieved by injecting an autologous blood clot into the left internal carotid artery. Cerebral blood flow was measured with [15O]H2O before and 1, 2, 4, 6, and 24 hours after embolization. CMRglc was measured with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) 24 hours after embolization. Lesion size and location 24 hours after embolization was determined by the 2,3,5-triphenyltetrazolium chloride (TTC) staining method. The results are summarized as follows: (1) 1 hour after embolization, CBF in the temporal cortex and the basal ganglia decreased to < 40% of the contralateral values. In these regions, regarded as an ischemic core, CBF decreased further with time and CMRglc at 24 hours also decreased. Infarcted lesions as indicated by being unstained with TTC were consistently observed in these regions. (2) In the parietal cortex and several regions surrounding the ischemic core, CBF was > 40% of the contralateral values 1 hour after embolization and recovered gradually with time (ischemic penumbra). In these regions, CMRglc at 24 hours increased compared with that in the contralateral regions, indicating an uncoupling of CBF and CMRglc. No obvious TTC-unstained lesions were detected in these regions. The authors demonstrated a gradual recovery of reduced CBF, an elevated CMRglc and a CBF-CMRglc uncoupling in the penumbra regions of the primate model. Positron emission tomography investigations using this model will provide better understanding of the pathophysiology of thromboembolic stroke in humans.
 ...
PMID:Serial changes in cerebral blood flow and flow-metabolism uncoupling in primates with acute thromboembolic stroke. 1129 74

Nuclear brain imaging is able to show functional abnormalities of lesions that are not detectable by CT and MR images. The diagnostic keys of nuclear-imaging in terms of clinical usefulness are its early detection of lesions and determination of the efficacy of drug and surgical therapies. In dementic patients, F-18 FDG brain images can be diagnosed as Alzheimer's disease 12 months earlier than is possible on CT and MRI images, and can provide information for effective drug therapy. O-15 water CBF images can predict the effect of Nicholin by assessing transient increases in cerebral blood flow (CBF), thereby facilitating improvement in higher brain functions such as orientation. In stroke patients, brain SPECT images with Tc-99m HMPAO can predict fatal cerebral hemorrhage caused by anti-thrombic therapy by showing the decrease in count ratio (count ratio of infarcted to contralateral area of < 0.34) in the acute phase and identifying disruption of the blood brain barrier by showing hyperfixation in the subacute phase. Brain SPECT with I-123 IMP can also identify "misery" perfused areas resulting from reduced CBF and decreased vasoreactivity in the chronic phase. This criterion is utilized for patient selection for extracranial/intracranial bypass surgery, because patients with areas of poor perfusion might be indicated for such surgery. Since nuclear medicine images can accurately select candidates for drug or surgical therapies, they will be beneficial in reducing Medicare costs as well as in enhancing patients' quality of life as a result of the successful treatment. With the advancement of technology, nuclear medicine units that can simultaneously obtain CT images and can combine functional with anatomical images will provide more useful information for the diagnosis of brain disease.
 ...
PMID:[Usefulness of SPECT images in helping radiologists understand brain diseases]. 1139 44

We report a 52-yr-old Korean woman with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) whose diagnosis was confirmed by skin biopsy and the presence of a novel mutation in the NOTCH3 gene. The patient's clinical features were rather unusual in that 1) clinical presentations were only two episodes of stroke and mild dementia unaccompanied by mood disturbances or migraine, and 2) there was no family history. Brain MRI showed T2 hyperintensities in both temporal pole areas in line with the recent suggestion by O'Sullivan et al. that the abnormality could be a radiologic marker of CADASIL. FDG-PET also showed a hypometabolism in the temporal pole areas with an abnormal finding on MRI in addition to the hypometabolism in cortical and subcortical regions. We could learn from this case that CADASIL may be included in the differential diagnoses in patients with vascular dementia associated with a small vessel disease, even in the absence of a family history, especially when there are no known stroke risk factors and when the MRI shows T2 hyperintensity in the temporal pole regions.
 ...
PMID:A novel mutation (C67Y)in the NOTCH3 gene in a Korean CADASIL patient. 1258 6

Intracardiac tumors are unusual and can originate within the heart or spread from other sites. This is a report of a patient who presented with a TIA, and during the subsequent stroke workup, a right hilar nonsmall cell lung carcinoma was discovered. The tumor had extended into the left atrium through a pulmonary vein. The hilar tumor as well as intracardiac extension were demonstrated by PET scanning using FDG.
 ...
PMID:Intracardiac extension of lung cancer demonstrated on PET scanning. 1642 87

Stroke produces an area of focal damage and distant areas of reduced blood blow and metabolism termed diaschisis. Tc-99m ECD and HMPAO brain SPECT have demonstrated crossed cerebellar diaschisis (CCD) in patients with cerebral cortical infarct. SPECT findings reflect abnormal cerebral blood flow. CCD as shown on F-18 FDG PET reflects abnormal reflects glucose metabolism. We present the case of a patient with laryngeal cancer who also had a stroke in the left cerebral hemisphere involving the territory of the middle cerebral artery 20 years ago. This patient underwent PET, including the head and neck. A current brain F-18 FDG PET exhibited hypometabolism in the contralateral cerebellum (CCD) as well as hypometabolism of the primary insult in the left cerebral hemisphere. These findings reflect partial impairment or diminished glucose metabolism in the primary insult to the cerebrum and contralateral cerebellum. In addition, this patient illustrates that on PET imaging, CCD could be demonstrated 20 years after a stroke.
 ...
PMID:F-18 FDG PET demonstrates crossed cerebellar diaschisis 20 years after stroke. 1662 31


1 2 3 4 5 6 7 Next >>