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Query: UMLS:C0917798 (cerebral ischemia)
 17,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diffusion-weighted MRI based on single-shot echo planar imaging (EPI) has been established as a useful tool to study acute cerebral ischemia. However, EPI is prone to spatial distortion and ghosting artifacts. In this study, a pulse sequence for diffusion-weighted imaging (DWI) based on a single-shot spiral readout is presented. Using this technique, multislice apparent diffusion coefficient (ADC) mapping can be performed in an interleaved fashion with the same temporal resolution as EPI. Other advantages associated with ADC mapping by the single-shot spiral method include minimal ghosting artifacts, reduced spatial distortion, and capability to scan in arbitrary planes. This technique has been successfully tested in five normal volunteers and three stroke patients. It has been demonstrated that the single-shot spiral technique is capable of producing high quality DWI and ADC trace maps (128 x 128) in the axial, sagittal, and coronal planes, which facilitate clinical diagnosis.
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PMID:ADC mapping by means of a single-shot spiral MRI technique with application in acute cerebral ischemia. 1002 22

Protective effects after focal cerebral ischemia were assessed in transgenic mice that overexpress in a neuron-specific fashion mouse Bcl-XL or human Bcl-2. Both Bcl genes were under the control of the same mouse Thy-1 regulatory sequences resulting in very similar expression patterns in cortical neurons. Furthermore, these sequences direct lateonset (i.e. around birth) expression in brain, thus minimizing effects of transgene expression during brain development. Effects on infarct volume were measured using MRI after permanent occlusion of the middle cerebral artery (MCA). When compared to their non-transgenic littermates, Thy1mbcl-XL mice showed a significant 21% reduction in infarct size whereas Thy1hbcl-2 mice did not reveal any reduction. These findings suggest a selective protective advantage of Bcl-XL as compared with Bcl-2 in this mouse model for human stroke.
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PMID:Neuron-specific transgene expression of Bcl-XL but not Bcl-2 genes reduced lesion size after permanent middle cerebral artery occlusion in mice. 1040 19

Metallothioneins (MTs) are a family of metal binding proteins that have been proposed to participate in a cellular defense against zinc toxicity and free radicals. In the present study, we investigated whether increased expression of MT in MT-1 isoform-overexpressing transgenic mice (MT-TG) affords protection against mild focal cerebral ischemia and reperfusion. Transient focal ischemia was induced in control (wild type) and MT-TG mice by occluding the right middle cerebral artery for 45 min. Upon reperfusion, cerebral edema slowly developed and peaked at 24 hr as shown by T2-weighted MRI. The volume of affected tissue was on the average 42% smaller in MT-TG mice compared with control mice at 6, 9, 24, and 72 hr and 14 days postreperfusion (P < 0.01). In addition, functional studies showed that 3 weeks after reperfusion MT-TG mice showed a significantly better motor performance compared with control mice (P = 0.011). Although cortical baseline levels of MT-1 mRNA were similar in control and MT-TG mice, there was an increase in MT-1 mRNA levels in the ischemic cortex of MT-TG mice to 7.5 times baseline levels compared with an increase to 2.3 times baseline levels in control mice 24 hr after reperfusion. In addition, MT-TG mice showed an increased MT immunoreactivity in astrocytes, vascular endothelial cells, and neurons 24 hr after reperfusion whereas in control mice MT immunoreactivity was restricted mainly to astrocytes and decreased in the infarcted tissue. These results provide evidence that increased expression of MT-1 protects against focal cerebral ischemia and reperfusion.
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PMID:Evidence for a protective role of metallothionein-1 in focal cerebral ischemia. 1053 15

A diagnosis of moyamoya disease was made in three children aged five, eight and 13 years (including two Turkish sisters). Clinical presentation was recurrent episodes of cerebral ischemia and stroke. CT scans and MRI showed infarcts in various distributions. Angiography revealed anterior bilateral stenosis of the circle of Willis and development of Moyamoya collateral pathways. In one case there was coagulopathy with protein C deficiency. To increase transdural collateral flow, revascularisation with encephalo-duro-arterio-synangiosis was attempted in all three children. Outcome was clinically and angiographically satisfactory and none of the children developed further neurological complications. The current state of study on Moyamoya disease is also presented.
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PMID:[Moyamoya disease: advantage of early diagnosis and survival treatment. Review of three cases]. 1058 42

Using a magnetic resonance (MR) imaging method, absolute measurements of in vivo brain water content were obtained in 15 male Long Evans rats that underwent a 90-min focal cerebral ischemia. A strong linear relationship (r = 0.80) with a slope of 1 was observed when correlating MR-measured water content to that obtained with the ex vivo wet/dry measurements. This effective spin-density-based method is the first-reported in vivo absolute quantification of brain tissue water content associated with a pathophysiological state and preliminary findings suggest that a noninvasive measurement of brain water content can be obtained with MRI.
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PMID:Absolute measurements of water content using magnetic resonance imaging: preliminary findings in an in vivo focal ischemic rat model. 1064 42

A 47-year-old man developed progressive muscular weakness in the left arm. MR images revealed low intensity signal lesions with ring enhancement by Gd-DTPA in right fronto-parietal lobes. At that time cerebral angiography was not performed because he refused. A tuberculin skin test showed strongly positive reaction and then administration of anti-tuberculous drugs was started. His symptom had remained stable for one year, but left facial palsy and dysarthria added about two years later. MR images revealed expansion of the lesions in right parietal lobe, adding cortical high intensity signal lesions with Gd-DTPA enhancement on T1-weighted images. Angiography disclosed tubular stenosis of right internal carotid artery at the portion of cervical to petrous segment and the local stenosis at right renal artery. These lesions were considered to be caused by fibromuscular dysplasia, but not atherosclerosis, because we could not find any atherosclerotic lesions in other arteries including right carotid bifurcation. His manifesting symptoms were ascribed to slowly progressive cerebral ischemia. And peculiar MRI findings in his early stage resembled those of inflammatory granulomatous diseases.
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PMID:[A peculiar MRI findings in a case with slowly progressive cerebral ischemia caused by internal carotid artery stenosis possibly due to fibromuscular dysplasia]. 1065 64

Rodents have been extensively used for experimental stroke research with rat and gerbil the preferred species. With the advent of transgenesis and gene targeting the number of mutant mouse strains is rapidly increasing. Thus, mouse models of stroke will be of great importance in the analysis of genetic factors affecting stroke. Demonstrating long-term functional recovery is of paramount importance for the pharmacological evaluation of putative stroke therapies. In the present paper we induce mild focal cerebral ischemia by tandem occlusion of the right middle cerebral artery (MCA), via craniotomy, together with the common carotid artery for 45 min in C57BL/6 strain of mice. The effects of ischemia were evaluated acutely by MRI and long-term (> 3 weeks) sensorimotor functional deficits were analyzed using a number of behavioral paradigms including the rotorod, wire hang, horizontal surface approach, eye-closure reflex, and T-maze tests. Although the induced brain damage is mild we show that it leads to clearly detectable and significant sensorimotor defects associated with fine motor coordination, balance, and postural and sensory reflexes. We conclude that the applied behavioral tests will be useful in the analysis of stroke in mutant mice.
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PMID:Transient focal cerebral ischemia induces sensorimotor deficits in mice. 1068 Jul 58

Cerebral white matter lesions, such as leukoaraiosis, may be a result of damage from cerebral ischaemia, and may also be associated with the degenerative process in Alzheimer's disease. The apolipoprotein epsilon4 (apoepsilon4) genotype is a genetic risk factor for both Alzheimer's disease and ischaemic brain damage through acceleration of atherosclerosis. The aim was to determine whether apoepsilon4 may be related to the formation of cerebral white matter lesions in Alzheimer's disease. The association of apoE genotype, sex, age, and the presence of several vascular risk factors, with the presence of white matter lesions in 55 patients clinically diagnosed with Alzheimer's disease was investigated. The cerebral white matter lesions were identified by T2 weighted MRI and classified on a 4 grade scale from no lesion to diffuse lesion. The odds ratio (OR) of the factors mentioned above to the presence of white matter lesions was determined and tested by Fisher's exact test. The association of the lesion grades with these factors was analysed by non-parametric tests. The apoE 4 genotype was strongly associated with Alzheimer's disease (p=0.0001), but not associated with the presence or the degree of cerebral white matter lesions in Alzheimer's disease (OR=1.09, p>0.99). Aging (>70 years old) was a significant risk factor for white matter lesions (OR=7.2, p=0.0006) and age was significantly correlated with the lesion (p=0.0075). The OR of female sex to the lesion grades was 2.89 (p=0.084) and the lesion grade of female sex was significantly higher than that of the male sex (p=0.047). Other vascular risk factors were not significantly associated with the presence of white matter lesions. These findings suggest that there is a sex difference in white matter pathology in Alzheimer's disease.
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PMID:Cerebral white matter lesions are not associated with apoE genotype but with age and female sex in Alzheimer's disease. 1076 1

Diffusion-weighted (DWI) echo-planar (EPI) MRI has been used for imaging acute ischaemic stroke. We used DWI and conventional spin-echo (SE) MRI to study the dynamics of ischaemic human stroke. We examined 30 patients (mean age 57.5 years, range 27-82 years, median 57 years) with a diagnosis of stroke. They were examined in the acute (120 min to 47 h, mean 15.3 h), subacute (8 days) and chronic (2-3 months) stages of ischaemia using clinical scores and MRI. Imaging was performed on an 1.5-T imager. Anisotropic DWI with diffusion gradients in all three axes, an isotropic tensor trace pulse DWI sequence and SE MRI were used. In all patients both DWI sequences showed a decrease in the apparent diffusion coefficient (ADC) in the acute stage, even when SE images did not reveal signal abnormalities. Clinical features correlated with lesion site but not size. The ADC was initially 19.6-43% less than that of nonischaemic tissue and increased to normal after 7 days in conventionally treated patients and after 2-5 days in patients who underwent intra-arterial fibrinolysis. In the chronic stage the ADC rose by up to 254.4 %. In patients who did not undergo fibrinolysis DWI changes correlated with the final infarct size (P<0.05). It was possible to differentiate acute from chronic ischaemic lesions. We conclude that DWI is a sensitive and practicable tool for detecting early cerebral ischaemia. It is possible to predict in the acute stage the final size of an infarct. DWI may be helpful for clinical decisions and for monitoring therapy.
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PMID:Diffusion-weighted imaging in ischaemic stroke: a follow-up study. 1077 39

In Crohn's disease, some concomitant neurological illnesses such as cerebral ischemia following arterial or venous thrombosis, subacute combined degeneration of the spinal cord following malabsorption of vitamin B12 or folic acid, opticus neuropathy, and polyneuropathy have been described. Cerebral vasculitis secondary to Crohn's disease seems to be a very rare phenomenon. We report on three such cases in three female patients (aged 26, 29, and 61 years). All patients became symptomatic with a hemiparesis; one complained additionally of a speech disorder, headache, and intermittent loss of orientation. In CT and MRI scans, multiple lesions were detected; cerebral angiography showed multiple stenoses of middle- and large-sized vessels that were compatible with cerebral vasculitis. Serologic tests concerning vasculitis were inconspicuous at that time. Under anticoagulation (in two cases) and immunosuppressive therapy, neurologic symptoms disappeared. In the following 6 to 12 months, no new neurological symptoms appeared. In two cases, Doppler sonographic controls showed stationary and, in one case, progressive intracranial stenoses. Since autoimmunologically caused inflammatory bowel diseases might be associated with vasculitis of other organs, the appearance of cerebral vasculitis secondary to Crohn's disease is a possible organ manifestation by inflamed vessels.
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PMID:[Cerebral vasculitis as a concomitant neurological illness in Crohn's disease]. 1079 98


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