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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Trained, chronically instrumented, conscious dogs were used to study the function of the left ventricle by first-pass radionuclide ventriculography (RNV). Six dogs were trained prior to a sterile left thoracotomy, where a left atrial catheter was implanted. After recovery of four days RNV was carried out by injecting a bolus of technetium-99m-DTPA via the catheter to the left atrium. The data was collected for 12 s to a computer by frame rate of 20 frames/s from left lateral view of the dog. The experiments were performed both in four-leg standing and in 60 degrees head-up tilted positions. The measurements were done with two injection volumes (0.25 and 1.0 ml/kg) to study the effect of volume on the results. The body position had effect on left ventricular end-diastolic and stroke volumes, whereas ejection fraction remained unchanged. In comparison of the two injection volumes a minor difference was found in left atrial emptying, while the differences in left ventricular function were non-significant. In spite of training and careful standardization of experimental procedures, relatively high individual variation between animals was found in most parameters studied. The first-pass RNV method proved to be promising for measuring the left ventricular function in conscious dogs. Although the left atrium has reflectory tachycardic potential to distension, the volumes used for RNV did not affect the results. The left ventricular adaptation to head-up tilting in conscious dogs seems to consist mainly of decrease in left ventricular volume without significant effect on ejection fraction.
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PMID:First-pass radionuclide ventriculography in conscious dogs. 357 12

Ratios of interhemispherical perfusion and blood flow were derived from 72 patients with reversible (TIA, PRIND) or irreversible (completed stroke) ischemic neurologic deficits. Differences from normal mean values (right-to-left: 1.00) were determined by employing CARNA with 99mTc-DTPA (perfusion) or DSPECT with 133Xe-gas (blood flow in ml/100 g/min). These differences were constantly higher for CARNA than for DSPECT. Such an excess for CARNA values was interpreted as the delay portion within the CARNA results, which increased from completed stroke (33% delay) to TIA (62% delay). The complement, i.e. the low flow portion, decreased in this sequence. Separation of CARNA values into delay and flow portions provides further information on the individual severity of cerebrovascular disease by employing a simple nuclear procedure. Moreover, it complements morphological findings from radiographic angiography and transmission CT.
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PMID:[Relative determination of hemisphere perfusion and hemisphere circulation. A comparison of the results of computer-assisted radionuclide angiography and dynamic single photon emission CT in patients with unilateral cerebrovascular disease]. 633 46

We measured the clearance from blood to pulmonary edema fluid of a small molecular weight hydrophilic radiotracer, Indium-111-DTPA (In-DTPA) and a larger molecular weight radiotracer, Iodine-125-HSA (I-HSA), in patients with pulmonary edema on either a cardiac or noncardiac (permeability) basis. In previous investigations, we had noted an apparent relationship between the magnitude of clearance of I-HSA across the alveolocapillary membrane and the severity of noncardiac pulmonary edema. In this study, we were able to distinguish at least 2 distinct groups of patients with noncardiac pulmonary edema. Patients with the greatest damage to the alveolo-capillary exchanging membrane, defined by the flux of I-HSA from blood to edema fluid, were significantly differentiated from those with a lesser microvascular injury on the basis of higher mean heart rate (HR), temperature, cardiac index (CI), pulmonary artery pressures, right ventricular stroke work index (RVSWI), and a lower mean total white blood cell count (WBC), among others. Therefore, noncardiac pulmonary edema is characterized by a spectrum of permeability injury to the pulmonary microvasculature which seems to parallel other measurable indices of the severity of the systemic response to the illness.
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PMID:Clinical correlates of the spectrum of lung microvascular injury in human noncardiac edema. 682 83

Computer assisted radionuclide angiography (CARNA) with 99mTc-DTPA was employed to study 143 patients with transient ischemic attacks (TIA) and 79 patients with prolonged reversible ischemic neurologic deficit (PRIND). The results of CARNA were compared with findings from radiographic angiography (RGA) in 173 patients and with findings in transmission computerized axial tomography (T-CAT) in 154 patients. In patients with TIA, CARNA showed a hemispherical perfusion deficit in 74.8%, and with PRIND 87.3%. This deficit, determined as the relative difference between the involved and the non-involved hemisphere, was significantly (p less than 0.0025) greater in PRIND (minus 23%) than in TIA (minus 17%). Sensitivity of CARNA was independent of the interval from ictus to examination for more than 4 months. RGA in TIA revealed true positives in 82.0%, in PRIND it was 89.5%. T-CAT was positive in TIA in only 16.8% but in PRIND it was 64.4%. Combined sensitivities in TIA (92.4%) and in PRIND (94.0%) were highest with the combination of CARNA and RGA. However, in PRIND the combination of non-invasive methods (CARNA and T-CAT) revealed 93.2% positive findings. Combinations of these evaluation methods may be used to detect cerebrovascular disease in patients with such dysfunction.
Stroke
PMID:Sensitivity of computer assisted radionuclide angiography in transient ischemic attack and prolonged reversible ischemic neurological deficit. Comparison with findings in radiographic angiography and transmission computerized axial tomography. 702 93

Brain imaging is performed using radiopharmaceuticals by single photon emission computed tomography (SPECT) and positron emission tomography (PET). SPECT and PET radiopharmaceuticals are classified according to blood-brain-barrier permeability, cerebral perfusion and metabolism receptor-binding, and antigen-antibody binding. The blood-brain-barrier (BBB) SPECT agents, such as 99mTcO4-, [99mTc]DTPA, 201TI and [67Ga]citrate are excluded by normal brain cells, but enter into tumor cells because of altered BBB. These agents were used in the earlier period for the detection of brain tumors. SPECT perfusion agents such as [123I]IMP, [99mTc]HMPAO, [99mTc]ECD are lipophilic agents and therefore, diffuse into the normal brain. These tracers have been successfully used to detect various cerebrovascular diseases such as stroke, Parkinson disease, Huntington's disease, epilepsy, dementia, and psychiatric disorders. Xenon-133 and radiolabeled microspheres have been used for the measurement of cerebral blood flow (CBF). Important receptor-binding SPECT radiopharmaceuticals include [123I]QNE, [123I]IBZM, and [123I]iomazenil. These tracers bind to specific receptors in the brain, thus displaying their distribution in various receptor-related cerebral diseases. Radioiodinated monoclonal antibodies were used for the detection of brain tumors. PET radiopharmaceuticals for brain imaging are commonly labeled with positron-emitters such as 11C, 13N, 15O, and 18F, although other radionuclides such as 82Rb, 62Cu and 68Ga also were used. The brain uptake of [13N]glutamate, [68Ga]EDTA and [82Rb]RbCl depends on the BBB permeability, but these are rarely used for brain imaging. Several cerebral perfusion agents have been introduced, of which [15O]water, [13N]ammonia, and [15O]butanol have been used more frequently. Regional CBF has been quantitated by using these tracers in normal and different cerebral disease states. Other perfusion agents include [15O]O2, [11C]CO, [11C]CO2, [18F]fluoromethane, [15O]O2, [11C]butanol, and [62Cu]PTSM. Among the PET cerebral metabolic agents, [18F]fluorodeoxyglucose (FDG) is most commonly used to detect metabolic abnormalities in the brain. Various brain tumors have been graded by [18F]FDG PET. This technique was used to detect epileptic foci by showing increased uptake in the foci during the ictal period and decreased uptake in the interictal period. Differentiation between recurrent tumors and radiation necrosis and the detection of Alzheimer's disease have been made successfully by [18F]FDG PET. Other PET metabolic agents such as [11C]deoxyglucose, and [11C]methylmethionine have drawn attention in the detection of brain tumors. [18F]fluorodopa is a cerebral neurotransmitter agent, which has been found very useful in the detection of Parkinson disease that shows reduced uptake of the tracer in the striatum of the brain.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Radiopharmaceuticals for brain imaging. 781 3

In the elderly, asymptomatic white matter hyperintensities are common on T2-weighted magnetic resonance imaging (MRI). In symptomatic patients, such MRI appearances correlate with varied postmortem findings including demyelination or stroke. What structural correlates underlie the T2 hyperintensities in patients whose lesions are asymptomatic is controversial. Therefore, in order to investigate the underlying metabolism and perfusion in white matter lesions (exhibiting T2 hyperintensity), 13 patients underwent proton magnetic resonance spectroscopy and dynamic gadolinium-DTPA perfusion-weighted MR imaging. N-acetyl aspartate (NA) levels were reduced in the lesions compared with age-matched controls (P = 0.031), implying neuronal/axonal loss. Creatine levels were also reduced (P = 0.001). Choline levels were unchanged in the lesions. Lactate was identified in the lesions of 5 of the 13 patients. Although not statistically significant, perfusion studies exhibited a trend toward lower cerebral blood volumes in patients with high grade extracranial carotid stenosis and lactate-containing lesions. These findings suggest that neuronal/axonal loss underlies the majority of T2-weighted asymptomatic lesions in the older population, and in many cases these changes may be due to chronic ischemia.
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PMID:Proton magnetic resonance spectroscopy and gadolinium-DTPA perfusion imaging of asymptomatic MRI white matter lesions. 789 36

A case of multiple intracranial tuberculous nodule following miliary tuberculosis was reported. The case was a 19-year-old woman visited a general practitioner, because of fever. Chest x-ray film on the first visit showed diffuse granular shadows in her both lungs with pleural effusion in the left side. The case was diagnosed as bacterial pneumonia, and was treated with antibiotics. She had been getting worse, and the doctor finally examined her sputum, and tubercle bacilli were seen in her sputum (Gaffky 4) by the Ziehl Neelsen's staining. She was introduced to our hospital. Chest x-ray film on admission showed diffuse granular shadows in her both lungs and she was diagnosed her as miliary tuberculosis, and anti-tuberculous therapy was quickly started. She didn't complain of any neurological disorders, but her brain CT showed several nodules in the left cerebral cortex enhanced with contrast medium. T1 weighted MRI enhanced by Gd-DTPA revealed abnormal enhancements in the cerebrum, the cerebellum, and the midbrain. She was treated with anti-epileptic drugs, but after 65 days, she started to suffer from epileptic stroke. Six months later, her brain lesions have improved by the use of anti-tuberculosis drugs and anti-epileptic drugs. The incidence of tuberculosis has decreased in Japan, and, many doctors did not show concern on, thus, a doctor's delay is a serious problem in Japan. Advocary should be made to doctors to detect tuberculous patients as early as possible.
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PMID:[Asymptomatic multiple intracranial tuberculous nodules detected in a case of miliary tuberculosis]. 804 Oct 61

A cerebral vasodilatory capacity map, consisting of a 99mTc-DTPA-HSA SPECT image obtained after acetazolamide injection minus the baseline image, was produced in a patient with moyamoya disease. The map demonstrated diminished capacity in the posterior region of the right cerebral hemisphere. Subsequently, cerebral infarction occurred in the corresponding area. This observation suggests that regions of low vasodilatory capacity identified by cerebral vasodilatory capacity mapping may be at high risk of ischemic stroke.
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PMID:Cerebral vasodilatory capacity mapping using technetium-99m-DTPA-HSA SPECT and acetazolamide in moyamoya disease. 822 45

A carotid embolic stroke model in rats was studied with a combination of diffusion- and perfusion-sensitive magnetic resonance (MR) imaging at 4.7 T. Capillary blood deoxygenation changes were monitored during formation of focal ischemia by acquiring multisection magnetic susceptibility-weighted echo-planar images. A signal intensity decrease of 7% +/- 3 in ischemic brain (1% +/- 2 in normal brain) was attributable to a T2* decrease due to increased blood deoxygenation, which correlated well with subsequently measured decreases in the apparent diffusion coefficient. The same multisection methods were used to track the first-pass transit of a bolus of dysprosium-DTPA-BMA [diethylenetriaminepentaacetic acid-bis(methylamide)] to assess relative tissue perfusion before and after stroke and after treatment with a thrombolytic agent. Analysis of contrast agent transit profiles suggested a total perfusion deficit in ischemic tissue and essentially unchanged perfusion in normal brain tissue after stroke.
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PMID:Perfusion and diffusion MR imaging of thromboembolic stroke. 840 May 61

The aim of the study was to compare the first-passage profiles of dysprosium diethylenetriamine penta-acetic acid bis(methylamide) (DTPA BMA) and the superparamagnetic iron oxide particles NSR 0430 in regions with severe and moderate cerebral ischemia. In seven rats subjected to middle cerebral artery occlusion, two dynamic MR perfusion imaging series were acquired after intravenous bolus injections of .5 mmol/kg dysprosium DTPA BMA and .06 mmolFe/kg iron oxide particles, respectively. The doses were chosen to obtain similar maximum signal change in normally perfused brain. The first-passage profiles were compared in a region of interest (ROI) in the core area with severe ischemia and in a ROI in the penumbra area of moderate ischemia. The results were compared both as the calculated mean signal intensity versus time curves for all seven rats and statistically for an estimated mean transit time (MTT) after gamma variate fitting of the calculated concentration versus time curves. The first-passage profiles for the two contrast agents were similar, both in the core area of severe ischemia and in the penumbra area of moderate ischemia. In this rat stroke model, dysprosium DTPA BMA and the superparamagnetic iron oxide particles NSR 0430 were found to be equally efficacious for the diagnosis of the perfusion deficit, but if safe for human investigations, iron oxide particles would have an advantage as equal susceptibility effect may be achieved with smaller injection volumes.
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PMID:Comparison of dysprosium DTPA BMA and superparamagnetic iron oxide particles as susceptibility contrast agents for perfusion imaging of regional cerebral ischemia in the rat. 889 8


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