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)

The uptake and retention in a 2 cm thick brain section was recorded serially by SPECT after i.v. injection of [99mTc]-d,l-HM-PAO (HM-PAO). In 16 patients, the fraction of the administered dose retained by the brain was 5.2 +/- 1%, showing a peak after 40-50s, then decreasing by 10% within the first 10 min and then by only 0.4% per hour. The image contrast was measured in each patient as the regional hemispheric asymmetry difference in percent of the highest value of the two regions. It decreased from 31% at 30-40 s to 25% at 10 min. At 24 h, a value of 19% was reached. Using the images obtained at 10 min after injection, a region to region comparison of the original and corrected HM-PAO images to the xenon-133 regional cerebral blood flow (rCBF) images was performed. Forty-four patients with stroke, epilepsy, dementia, basal ganglia disease, and tumors and control subjects were included in this comparison. The algorithm proposed by Lassen et al. was used to correct the original images for back diffusion of tracer (brain to blood); a good correlation very close to the line of identity between the corrected HM-PAO and xenon-133 data was obtained when using a conversion/clearance ratio of 1.5 and when the noninvolved hemisphere was used as a reference region (r = 0.86, p less than 0.0001). Serial arterial and cerebral venous blood sampling was performed over 10 min following i.v. injection of HM-PAO in six patients. An overall brain retention fraction of 0.37 +/- 0.03 (mean +/- SEM) was calculated from the data. An average CBF of 0.62 +/- 0.12 ml/g/min was determined on the basis of the Fick principle; this compared to a value of 0.59 +/- 0.09 ml/g/min (mean +/- SEM) measured by the xenon-133 inhalation method. The two sets of CBF values correlated linearly with a correlation coefficient of 0.97 (p less than 0.01). Inserting the average CBF value for the hemisphere as measured by the Fick principle into the algorithm described by Lassen et al. yields absolute rCBF values (ml/g/min) directly from the corrected HM-PAO images.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Quantitative measurements of cerebral blood flow using SPECT and [99mTc]-d,l-HM-PAO compared to xenon-133. 326 80

To examine the capacity of detecting regional cerebral blood flow (rCBF) disturbances in stroke, measurements with 133Xe inhalation and 123I-amphetamine (IMP) SPECT were performed within 1-2 days in 19 patients. IMP SPECT images in transverse sections consisting of outer and inner areas were correlated with 32 regions of 133Xe rCBF. 133Xe rCBF was assessed by ISI, CBF15, and F1. Inter hemispheric ratio correlation showed outer IMP uptake correlated better with 133Xe CBF indices than the inner one. With higher ratios of 133Xe rCBF. IMP uptake ratios were variable, suggesting less usefulness of this parameter in evaluation of mild ischemia. Values of IMP in outer regional hypo and hyperemic areas correlated better with those of 133Xe rCBF than the inner ones. In regional ratios of hypo and hyperemic areas from hemispheric mean, outer IMP uptake correlated with 133Xe CBF indices, reflecting regional disturbances of fast clearing tissue perfusion. Regression lines between ratios in 133Xe CBF and IMP uptake were located below one to one correlation, and dissociated more for hyperemic regions. IMP SPECT correlated better with 133Xe rCBF for tissues with reduced perfusion but underestimated hyperemic regions as measured with the 133Xe method. The data suggest outer cerebral IMP uptake evaluated by SPECT could reflect flow disturbances in the brain cortex.
 ...
PMID:Semiquantifying regional cerebral blood flow by 123I-amphetamine (IMP) SPECT in cerebrovascular disorders: correlations with CBF indices by 133Xe inhalation method. 326 88

Cerebral rCBF, rOEF, rCMRO2, and rCBV in moyamoya disease were studied by means of positron emmission tomography (PET), using 15O as a tracer. Steady-state methods with C15O2 and 15O2 were used to obtain the functional images of rCBF, rCMRO2, and rOEF. The 15O single-inhalation method was used to obtain the rCBV image. Five children (two boys and three girls) with mean age of 11 years and eight normal volunteers with mean age of 31 years were included in the study. The symptoms of moyamoya disease were due to cerebral ischemia, such as transient ischemic attack (TIA), reversible ischemic neurological deficit (RIND), and minor stroke. The interval between the latest ictus and PET scan ranged from 3 days to 3 years 6 months. Physiological parameters (rCBF, rCMRO2 etc.) in cerebral gray matter, cerebral white matter and basal ganglia were calculated from the single functional images. Any, low density areas appearing in X-ray-CT performed just prior to the PET study were carefully excluded from the analysis. The parameters of moyamoya disease were statistically compared with normal control parameters. Though the value of rCBF was slightly higher in moyamoya disease, this difference was not statistically significant. On the other hand, in moyamoya disease rCBV increased significantly in gray matter, white matter, and basal ganglia. The ratio of CBF to CBV is considered to be the index of perfusion pressure and reciprocal of cerebral mean transit time under the normal autoregulation of CBF. This ratio was calculated and compared with the normal value for each tissue.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Cerebral circulation and oxygen metabolism in moyamoya disease of ischemic type in children. 326 63

Cerebral hemodynamic and metabolic changes, occurring during delayed hypoperfusion following transient cerebral ischemia, and the influence of treatment with almitrine plus raubasine were studied in mongrel dogs. 10 min of transient cerebral ischemia was induced by bilateral clamping of both carotid and vertebral arteries. After declamping, the mean time necessary until cerebral venous PO2 (cvPO2) reached a value of 3.6 kPa, threshold for tissue hypoxia, was 80 min. At this time (T0), venous cerebral blood flow (vCBF) and cerebral perfusion pressure (Perf P) were below (60 and 20%, respectively) preischemic values, while cerebral vascular resistance (CVR) and oxygen and glucose extraction rates increased despite a normal cerebral oxygen consumption (CMRO2). At T0 ventilatory assistance without (control group) or with (treated group) intravenous infusion of almitrine plus raubasine was applied for 110 min. Between T0 and T110 min, 2 dogs died in the control group. During this period vCBF decreased by more than 60% in the control group while it slightly increased in the treated group. A strong decrease in Perf P (40%) and increase in CVR (140%) was observed in the control group while in the treated group Perf P and CVR slightly decreased (14 and 35%, respectively). CMRO2 decreased by 60% in the control group but remained within the normal range in the treated group. The fact that cvPO2 remained constantly below the initial value of 3.6 kPa in the control group and, on contrary, above this value in the group infused with raubasine plus almitrine indicates that the vCBF improvement leads to an increase in oxygen supply and is involved in the keeping of the adequacy between flow and metabolism. Our results support the hypothesis that the post-ischemic syndrome may play an important role in the acute prognosis of stroke. They clearly indicate that early cerebral resuscitation by infusion of almitrine plus raubasine, maintaining oxygen availability and CBF above initial thresholds, should improve the long-term neurological outcome.
 ...
PMID:Curative effect of an almitrine-raubasine combination in the postischemic syndrome following transient cerebral ischemia in dogs. 336 2

The effect of the possible influence of a new calcium antagonist, PY 108-068, on regional CBF was studied in patients suffering acute ischemic stroke. The dosage was 1.5 + 2.5 mg intravenously in six patients (series 1) and 2.5 + 5.0 mg intravenously in five other patients (series 2). CBF was measured before and after treatment by xenon-133 inhalation and single-photon emission computed tomography (Tomomatic 64). In the first series, no changes in hemispheric CBF, MABP, or clinical symptoms were noted after treatment, but one patient showed an increase of CBF in part of the periinfarct area. In the second series, slight increases in mean hemispheric flow values were seen, but in three of the five patients CBF decreased even further in the ischemic area. MABP decreased by 13%, and the clinical symptoms were unchanged.
 ...
PMID:Calcium antagonist (PY 108-068) treatment may further decrease flow in ischemic areas in acute stroke. 348 42

Eighteen patients were studied for cerebral blood perfusion abnormalities using N-isopropyl I-123 p-iodoamphetamine (IMP) and rotating dual gamma camera emission computed tomography (ECT). All were stroke patients, 10 with cerebral vasospasm after an aneurysmal rupture, 3 with an occlusion of the middle cerebral artery, 2 with an occlusion of the internal carotid artery (IC), one with an IC stenosis, one with Moyamoya disease and one with RIND. Four patients had extracranial-intracranial (EC-IC) bypass operations. In three of them, CBF studies were done before and after bypass surgery. An arterial line was placed in the left radial artery and connected to a Harvard pump. IMP (1.5-3 mCi) was injected into an arm vein while at the same time an arterial blood sample was withdrawn at a constant speed for 5 minutes. Scanning was started 35 minutes after IMP injection. After a scan, multiple transverse, coronal and sagittal section images were reconstructed with a minicomputer. We determined the values of regional CBF in the regions of interest using an image. Transmission computed tomography (CT) studies were performed on the same day. In eight patients, CBF study by 133Xe inhalation method (NOVO cerebrograph) was done. ECT showed diffuse low perfusion in two patients and focal low perfusion in 16 patients while CT showed abnormalities in 9 patients (50%). ECT abnormalities were more extensive than CT abnormalities. The values of rCBF in the superficial brain determined by ECT were similar to those examined by the inhalation method (ISI). Significant increase in rCBF was observed after the bypass operations.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Cerebral blood flow studies using N-isopropyl I-123 p-iodoamphetamine in cerebral ischemic lesions]. 348 81

Regional CBF (rCBF) and regional cerebral blood volume (rCBV) were evaluated by N,N,N'-trimethyl-N'-(2)-hydroxy-3-methyl-5-[123I]iodobenzyl-1, 3-propanediamine-2 HCl- and 99mTC-labeled red blood cells, respectively, and single-photon emission computerized tomography (SPECT) in a patient with focal cerebral ischemia. Sequential transmission computerized tomography (TCT) and SPECT functional data were compared with clinical findings to monitor the pathophysiological events occurring in stroke. A lack of correlation between rCBF-rCBV distributions and blood-brain barrier (BBB) breakdown was found in the acute phase. In the face of more prolonged alteration of BBB, as seen by TCT enhancement, a rapid evolution of transient phenomena such as luxury perfusion was shown by SPECT studies. Follow-up of the patient demonstrated a correlation between the neurological recovery and a parallel relative improvement of the cerebral perfusion.
 ...
PMID:Sequential assessment of regional cerebral blood flow, regional cerebral blood volume, and blood-brain barrier in focal cerebral ischemia: a case report. 348 73

A very simple and low-cost brain dedicated, rapidly rotating Single Photon Emission Tomograph SPECT is described. Its use in following patients with ischemic stroke is illustrated by two middle cerebral artery occlusion cases, one with persistent occlusion and low CBF in MCA territory, and one with early lysis of the occlusion having high CBF (massive luxury perfusion) for some weeks. Evidence of this kind may be essential in the evaluation of therapeutic measures in ischemic stroke.
Stroke
PMID:Monitoring CBF in clinical routine by dynamic single photon emission tomography (SPECT) of inhaled xenon-133. 349 85

To investigate changes in cerebral circulation and oxygen metabolism during aging, regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rOEF), regional cerebral metabolic rate of oxygen (rCMRO2) and regional cerebral blood volume (rCBV) were measured using the 15O labelled gas inhalation technique and a multi-slice positron emission tomograph (PET) in 22 healthy volunteers, aged from 26 to 64 years old. The measurements were performed with subjects at rest, without sensory deprivation. The values of rCBF, rOEF, rCMRO2 and rCBV in more than 40 anatomical structures of the brain were evaluated by studying a large series of scans in each region of interest after the functional PET image had been anatomically identified using x-ray computed tomographic images corresponding to the PET. In mean gray values, only CMRO2 showed significant reduction with age. rCMRO2 significantly decreased with age only in the supratentrium, and much more in the left hemisphere. Especially remarkable was rCMRO2 reduction in the left caudate region. Both CBF and OEF were variable and less age-dependent. It was concluded that CMRO2 could be reflecting healthy brain aging most properly.
Stroke
PMID:Reduction in regional cerebral metabolic rate of oxygen during human aging. 349 86

A study with positron emission tomography (PET) was performed on 10 patients with ischemic stroke and mild disability. The patients underwent cerebral angiography, x-ray computed tomography (CT) scan and regional cerebral measurements of CBF, CMRO2, oxygen extraction ratio (OER), and cerebral blood volume (CBV). Only minor arterial involvement was detected by angiography. In all patients, PET images of functional defects were more extensive than the corresponding CT hypodensity, and there were statistically significant reductions in CBF, CMRO2, and CBF/CBV ratio as compared with control subjects. Half of the regions analyzed in the affected hemisphere demonstrated a disruption of the normal coupling between CBF and CMRO2 as reflected by OER values significantly higher or lower than those of the corresponding region of the contralateral hemisphere. The pathophysiological pattern of high OER combined with a reduction in CBF proportionally greater than the reduction in CMRO2 was particularly indicative of regional chronic hemodynamic compromise in these patients.
 ...
PMID:Positron emission tomography in minor ischemic stroke using oxygen-15 steady-state technique. 349 26


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>