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

We investigated the clinical profile, etiological factors, neuropsychological features and radiological characteristics of 17 cases of striatocapsular infarction (SCI). SCI was defined as the following CT criteria: the area of infarction included the internal capsule and striatum, the maximum diameter of the lesion exceeded 2.0 cm without cortical involvement. There were 9 men and 8 women with mean age of 58 years. Five patients had lesions mainly involving the caudate head (anterior type) and the other 12 had lesions mainly involving the putamen (lateral type), 6 with left side lesion and 6 with right side lesion. Motor weakness was observed in all patients, and the upper extremities were preferentially involved, while in 9 patients face, upper and lower extremities were simultaneously involved. Etiological investigation revealed that 8 patients were cardioembolic stroke, 2 were artery-to-artery embolism and 2 were MCA stem occlusive disease, while the remaining 5 were undetermined. When compared with patients with lacunar infarction (LI), patients with SCI had significantly more frequent cardioembolic sources (47% vs 17%, p < 0.05) and less frequent hypertension (41% vs 80%, p < 0.01). In acute phase, neuropsychological abnormalities were found in 15 patients. Anterior type patients had psychiatric symptoms such as abulia, depression and agitation, while left lateral type patients had aphasia and right lateral type patients had hemispatial neglect or anosognosia. These symptoms gradually improved, although in most patients subtle abnormalities lasted over chronic phase. In 11 out of 13 patients who underwent SPECT using 99mTc-HMPAO, blood flow was decreased in overlying cerebral cortex besides the infarcted area.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Clinical investigation of striatocapsular infarction]. 833 92

Diffusion-weighted, echo-planar imaging (EPI) was used to map regional changes in the apparent diffusion coefficient (ADC) during experimental focal ischemia in the rat brain following permanent middle cerebral arterial occlusion (MCAO). Sixteen 64 x 64 diffusion-weighted EPIs were acquired in 32 s with successively increasing amplitudes of the diffusion-sensitive gradient pulses. A linear least-squares regression algorithm was used to fit 15 of the 16 two-dimensional matrices, on a pixel-by-pixel basis, to solve for the slope from which the ADC value was calculated. The correlation coefficient of the fit, R2, was used to filter the final ADC maps, and the ADCs were then scaled appropriately to be displayed in a 256 gray level format. Ranges (bins) of 0.05 x 10(-3) mm2/s were then grouped and color coded to qualify and quantify the evolution of ischemia in the MCA territory. The percentage of area in the ischemic and contralateral hemispheres in seven ADC bins were calculated at 30, 60, and 120 min after MCAO for 10 animals and demonstrated a significant increase in ADC bins below 0.45 x 10(-3) mm2/s and a decrease in bins above 0.50 x 10(-3) mm2/s over time. The postmortem infarct area, as measured by TTC staining, was highly correlated with the portion of the ischemic hemisphere falling below ADC values of 0.55 x 10(-3) mm2/s at 2 h after stroke onset. These studies suggest that focally ischemic brain tissue can be quantitatively subdivided according to ADC values and that ADC values below 0.55 x 10(-3) mm2/s 2 h following ischemia highly predict infarction in a rat permanent occlusion stroke model.
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PMID:Apparent diffusion coefficient mapping of experimental focal cerebral ischemia using diffusion-weighted echo-planar imaging. 841 2

MCA occlusion in animals is a common model for experimental stroke. In previous studies we have shown that one of the factors, which influence evolution of an infarct is microthrombosis in the area of infarction and in the surrounding brain tissue. The present study was undertaken for assessment of the number of microthrombi and of the size of brain infarcting in rats treated with the antiaggregatory substance Triflusal. 7 groups of Sprague-Dawley rats, each group consisting of 6 animals, underwent transsphenoidal MCA occlusion. The animals received Triflusal in various amounts from day 2 till day 6. At day 7 animals were decapitated and the brains were fixed in formaldehyde. The brain was dissected at the level of the optic chiasm and embedded in paraffin. Fresh microthrombi were detected py PTAH (Phosphotungstic acid hematoxylin) staining. In each animal the hemisphere with the ischemic lesion as well as the contralateral hemisphere were examined. The area of both hemispheres was calculated by subtraction of the ventricle area from the total brain area of a section. Infarct was defined as the region of necrosis which was sharply demarcated from normal brain. The infarcted area was planimetrically measured to obtain a ratio of infarcted to normal brain. A correlation between the effect of Triflusal, number of microthrombi and size of the infarcted area could be demonstrated. The pathogenetic role of the microthrombi in the evolution of cerebral infarction as well as the effect of Triflusal in different dosages on the number of microthrombi could be clearly assessed by quantitative morphometry.
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PMID:Morphometrical evaluation of triflusal in brain infarction. 842 55

Local cerebral hemodynamics and oxygen metabolism were measured by positron emission tomography (PET) with the oxygen-15 (15O) steady-state method in baboons, immediately before (T0), 1 (T1), and 3-4 (T2) h after permanent middle cerebral artery occlusion (MCAO). At T1, there was a marked fall in both cerebral blood flow (CBF) and the CBF/cerebral blood volume (CBV) ratio in the occluded territory; these changes were sustained at T2, indicating stable reduction in cerebral perfusion pressure and lack of spontaneous reperfusion within this time range. Compared with preocclusion conditions, the oxygen extraction fraction (OEF) in the occluded territory was elevated at both T1 and T2, indicative of a persistent oligemia/ischemia for up to 3 h after MCAO. At T2, however, this OEF increase had lessened, concomitantly with a decline in cerebral metabolic rate of oxygen (CMRO2). This impairment of oxidative metabolism occurred earlier in the deep, compared with the cortical, MCA territories; in the latter, the CMRO2 was essentially preserved at T1 and only moderately reduced at T2, possibly suggesting prolonged viability. Finally, no significant changes in CBF or CMRO2 were observed in the contralateral MCA territory in this time range after MCAO. Despite methodological limitations (mainly partial volume effects related to PET imaging, which may have resulted in an underestimation of true changes and an overlooking of heterogeneous changes) our study demonstrates the feasibility of the combined PET-MCAO paradigm in baboons; this experimental approach should be valuable in investigating the pathophysiology and therapy of acute stroke.
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PMID:PET study of changes in local brain hemodynamics and oxygen metabolism after unilateral middle cerebral artery occlusion in baboons. 847

In 36 patients 3 month after ischaemic stroke in regions supplied by MCA (Middle Cerebral Artery) physical examination, CT scanning and blood flow velocity recordings in ICA (Internal Carotid Artery) and MCA were performed. In both MCA blood flow velocity was measured in resting state and after 30 sec. of hyperventillation. The control group consisted of 40 healthy volunteers. In the control group blood flow decrease after hyperventillation was nearly equal in both hemispheres (38% in right and 37% in the left hemisphere). In studied group in the symptomatic hemisphere blood flow reduction was 21%. Vasoreactivity in the opposite hemisphere was similar to that in control group (35% decrease). The results suggest that vasoreactivity diminution is a local phenomenon limited to the infarcted area. Hyperventilation test, despite its simplicity, seems to be sufficient for screening vasoreativity.
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PMID:[Transcranial Doppler ultrasonography and hyperventilation test in assessment of cerebral vasoreactivity after ischemic stroke]. 854 27

We focus our attention in this presentation to the extracellular ionic changes during and after local ischemia and in repetitive versus single global ischemia. In the cat stroke model of MCA occlusion a considerable variability in the severity of ischemia was observed. This was demonstrated in electrical activity (ECoG), NAD/NADH fluoro-reflectometry and extracellular ionic changes. A striking experience was, that the K+ recovery is rather fast even after two hours of ischemia, and this is partly due to maintained activity of the sodium-potassium pump. After the MCA release a secondary acidosis occurs, which is the result of excess lactic acid production. This lactacidosis is certainly contributes to the late morphological damage. The repeated acidotic insult (in gerbil model of global cerebral ischemia) could be the cause of the more severe morphological and blood-brain-barrier damage in the repetitive ischemia too. The acidosis in many cases is even more pronounced after relieving the carotid arteries. This secondary acidosis causes endothelial damage and vasogenic oedema.
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PMID:Ion and metabolic disturbances after global and focal cerebral ischemia. 857 39

Vascular disease and focal cerebral ischemia still represent the major cause of neurological morbidity and mortality. Mechanisms of hypoxic changes are associated with energy depletion and impairment of biological membranes. Reperfusion after the stroke plays an important role in the development of morphological and functional changes of the nervous tissue. In experiments, different models of focal cerebral ischemia based on the middle cerebral artery occlusion (MCAO) are used. Four main categories of such models are most frequently employed: 1. Temporary intraluminal occlusion of part of the circle of Willis (via internal carotid artery), 2. Abluminal application of the vasoconstrictor peptide (endothelin-1) to the MCA, 3. Tromboembolic models, 4. Microclips. Reliable quantification of morphological changes is also possible. Discussed models are used for testing different types of treatment of the cerebral ischemia, including pharmacological stimulation and blocking of individual membrane receptor systems.
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PMID:[Models of focal hypoxia of the central nervous system]. 863 Oct 55

Although a sequential 99mTc-HMPAO SPECT technique with Diamox test (seq-SPECT) is a simple and time-saving procedure to assess brain perfusion reserve, the influence of the first dose of the tracer on the second one is not negligible. Therefore, a subtraction of the rest-SPECT from the 2nd SPECT is widely-used. However, subtracted SPECT images not only need to be corrected for the injected dose and the radiochemical purity due to inherent instability of HMPAO but also are usually degraded in quality. This study was undertaken to resolve these problems utilizing a change ratio (CR) map. The CR map was obtained by dividing 2nd SPECT by rest-SPECT. Prior to subtraction, the 2nd SPECT was normalized with the ratio of the mean whole brain counts between both SPECTs. To validate CR map, 7 patients were studied with both seq-SPECT and 133Xe inhalation CBF measurement (Xe-CBF). The right to left count ratio obtained from the ROIs placed on MCA territory of CR map correlated well with that from Xe-CBF (r = 0.89, p < 0.01). Fifty-three patients with stroke underwent the seq-SPECT which was compared with the cerebral angiography (CAG) and classified into 4 groups according to the CR map. In 25 patients, all of the rest-, the subtracted-SPECT and the CR map did not show any difference between the affected side and the contralateral normal side. Seven patients with normal rest-SPECT showed decreased subtracted-SPECT counts and CR on the affected side. Three of them showed more than 75% stenosis on CAG. Four patients with the decreased counts both at the rest- and the subtracted-SPECT revealed no difference on the CR map suggesting the matched decrease of both blood flow and metabolism in the affected side. In conclusion, the CR map was a simple and useful method to evaluate the brain perfusion reserve with the seq-SPECT.
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PMID:[Usefulness of change ratio map in 99mTc-HMPAO SPECT with acetazolamide enhancement]. 868 79

A series of 62 patients treated surgically for one or several unruptured intracranial aneurysms is reported. 83 aneurysms were treated in 65 operations. The main locations of the aneurysms were: MCA 35%, ICA (posterior communicating) 22%, carotido-ophthalmic segment 12%, carotid bifurcation 11%, anterior communicating artery 11%, verterbro basilar artery 5%. The circumstances of discovery were: incidental 28%, multiple aneurysm 22%, headache 18%, ischemic episode 9%, mass effect 8%, seizures 6%. Overall, 8% of these unruptured aneurysms were certainly symptomatic, 58% were certainly asymptomatic, and for 34% the relationship with the mode of discovery was uncertain. The overall outcome of surgery was: good recovery 94%, moderately disabled 1.5%, severely disabled 1.5%, and death 3%. The post-operative complications were related to surgical technique in 2 cases, to a severe atherosclerotic state of the ICA in 1 case, and to the general arteriopathy of the patient in 1 case. The discussion reviews in the literature the various arguments developed in favor of an active treatment of the unruptured cerebral aneurysms. Three arguments are proposed. 1. The overall severity of the aneurysm rupture, with a mortality rate over 60%. 2. The cumulative risk of rupture of an unruptured aneurysm, which may be high in young patients (from 16 to 30% lifetime risk). 3. The good outcome of the surgical treatment of the unruptured aneurysm (mortality rate under 4%, morbidity rate approximately 6%). The operative risk is higher for large or giant aneurysms, for a patient with a history of ischemic cerebrovascular accident as mode of discovery, for elderly patients with arteriosclerotic thickening of ICA wall and aneurysm neck. The decision to treat or not to treat may be easier (mass-effect, multiple aneurysm, acute headache) or more difficult (chronic headache, hemorrhage of other origin, seizures, incidental discovery). The endovascular treatment with occlusion of the aneurysms sac by means of coils is more and more an alternative to surgical treatment, but requires a long follow-up to ensure the absence of reexpansion of the coil-embolized aneurysms. The screening for unruptured aneurysms, especially in cases with familial intracranial aneurysms is more and more often proposed. The authors' opinion now is surgical clipping of small and middle-sized aneurysms in young patients, without severe associated pathology, and clearly agreeing with surgery. The limit of age for surgery is usually 65 years except for those aneurysms discovered after a mass-effect. Elderly patients, giant aneurysms, patients with contra-indication for surgery, are proposed for endovascular treatment.
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PMID:Management of unruptured cerebral aneurysms. 871 35

The EC-IC Bypass Study Group could not detect any benefit from surgery compared to medical management in the prevention of stroke in 1985 [15]. During the past years surgical revascularization was re-evaluated and considered as an appropriate treatment for a small subgroup of patients with recurrent focal cerebral ischaemia and impaired haemodynamics. This retrospective study examines the long-term benefit and patency rate of bypass. We present a follow-up of 5.6 years of 47 patients, all of whom underwent bypass surgery after 1985. Forty patients suffered recurring transient ischaemic attacks due to uni- or bilateral internal carotid artery occlusion. Examination included neurologic status, TCD with CO2 or Diamox challenge, angiography, CT and SPECT scans. Neurological improvement was seen in 23% of patients with better results after early surgery, a worsening in 22% suffering further ischaemic events on a postoperative average of 2.8 years. Patency rate for vein graft material was 50%, for the STA-MCA procedure 91%. Occlusion of the vein graft occurred on an average after 1.4 years, other anastomosis after 2.7 years. We conclude that only few patients derived long-term benefit from EC-IC bypasses. Functioning of the bypass worsens over time, suggesting a role for surgery predominantly in the first year of ischaemic events due to insufficient collateral supply. Actual indications for bypass surgery may be patients with failure of maximal medical therapy and progressive ischaemia and haemodynamic compromise.
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PMID:Long-term evaluation of EC-IC bypass patency. 889 Sep 90


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