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

We report on four patients with a histologically proven diagnosis of arteritis temporalis and clinical and/or neuroradiological evidence of severe focal cerebral ischemia due to intracranial vasculitis. While one patient suffered from a transient ischemic attack, CCT and MRI scans of the other patients showed multiple lacunar infarctions, combined with territorial infarctions in two cases. Necropsy in one patient demonstrated generalized giant cell vasculitis in large and small cerebral vessels. We suppose that the cerebral involvement was provoked by insufficient steroid therapy of arteritis temporalis in two patients. In one case, remission could be achieved by a combination of high-dose steroids and cyclophosphamide; one further patient remitted under lower steroid dosage. Steroid therapy was ineffective in two patients, one of whom died due to secondary complications. We conclude that central nervous system affection is a rare but dangerous complication of arteritis temporalis and may present as cerebral micro- and macroangiopathy.
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PMID:Temporal arteritis with cerebral complications: report of four cases. 803 43

An imaging technique capable of detecting ischaemic cerebral injury at an early stage could improve diagnosis in acute or transient cerebral ischaemia. We compared the ability of superparamagnetically contrast-enhanced MRI and conventional T2-weighted MRI to detect ischaemic injury early after unilateral occlusion of the middle cerebral artery in 12 male Wistar rats. Permanent vessel occlusion was achieved by a transvascular approach, which has the advantage of not requiring a craniectomy. At 45-60 min after the procedure, the animals had conventional T2-weighted MRI before and after administration of a superparamagnetic contrast agent (iron oxide particles). Unenhanced images were normal in all animals. After administration of iron oxide particles, the presumed ischaemic area was clearly visible, as relatively increased signal, in all animals; this high signal area corresponded to the area of ischaemic brain infarction seen on histological studies. Magnetic susceptibility effects of iron particles cause low signal in normally perfused cerebral tissue, whereas tissue with reduced or absent blood flow continues to give relatively high signal. Our results suggest that superparamagnetic iron particles may significantly reduce the interval between an ischaemic insult and the appearance of parenchymal changes on MRI.
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PMID:MRI in acute cerebral ischaemia: perfusion imaging with superparamagnetic iron oxide in a rat model. 810 90

Clinical, radiological, and histological examinations were performed on eight patients with autosomal-dominant dentato-rubro-pallido-luysian atrophy (DRPLA) including an autopsy case, to investigate the abnormal findings of the cerebral white matter in DRPLA. Three of the eight patients were found to have diffuse low density on CT or diffuse high-signal areas on T2-MRI in the white matter of the brain. There were no correlations between abnormal findings in the white matter and the following factors; age of onset, duration of the disease, clinical manifestations, disease severity, Hachinski score, or EEG abnormality. Single-photon emission tomography failed to reveal any relative decrease in cerebral blood flow in the white matter, even in the three patients with abnormal findings in the white matter. MRI perfusion studies did not suggest any decrease in cerebral blood volume in any of the patients examined, but in the DRPLA patients the latency, i.e., the interval from the time of injection to the time of the minimum signal intensity, was significantly prolonged in comparison with the results in normal controls. On histopathological investigation, there was diffuse decreased staining in the centrum semiovale and deep white matter of the temporal lobes bilaterally, but no gliosis, or arteriolar thickening or hyalinization were detected. These findings confirmed that the lesions in the white matter in DRPLA are not attributable to cerebral ischemia. The abnormal findings are presumably the result of the degeneration which occurs in DRPLA itself.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Investigation of involvement of cerebral white matter in DRPLA--including MRI perfusion study]. 816 52

We reported a rare case of cortical blindness in cerebral ischemia following post-anoxic state confirmed by single photon emission computerized tomography (SPECT) and visual evoked potential. A 45-year-old woman who had been suffering from bronchial asthma was admitted to our hospital because of sudden progressive dyspnea and depressed consciousness. When she arrived at the hospital by ambulance, she was in hypoxic state and fell into cardiac arrest. Her respiratory condition gradually improved with respirator assistance, and she recovered consciousness, but complained of bilateral visual loss. She had no history of any neurological or psychiatric illness, nor of drug abuse. On neurological examination, she was alert and oriented. Light reflex, optic fundi, extraocular movement and other neurological findings were all normal, with the exception of bilateral blindness. EEG showed generalized slow background activity, but cranial CT scan and MRI showed no abnormalities. 99mTc-HMPAO SPECT indicated hypoperfusion in prominent bilateral occipital and parietal lobes. Simultaneous recordings of pattern reversal visual evoked potential (VEP) and electroretinograms (ERG) using transient checkerboard pattern reversal in 15 min and 30 min checks were recorded. The results showed normal b waves but absent P100 in the bilateral eyes. From the patient's neurological symptoms and the results of SPECT and VEP, she was diagnosed as cortical blindness in post-anoxic state. On the 30th hospital day, her visual acuity and visual fields improved, but she was suspected of having visual agnosia. Eighty-five days after the onset of the neurological abnormalities, no traces of visual disturbances were observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A case of cortical blindness confirmed by single photon emission computerized tomography and visual evoked potential]. 820 Jan 41

A 28-year-old female farmer, without vascular risk factors, developed a limited infarct of the pons, associated with a lymphocytic cerebrospinal fluid (CSF) pleocytosis. Titres of specific antibodies against Borrelia burgdorferi were high in serum and CSF. MRI confirmed an infarct in the territory of the medial pontine arteries, but angiography showed no evidence of cerebral angiopathy. Antibiotic therapy rapidly led to a return to normal of CSF cytology and serology. We suggest that Lyme disease is a possible cause of cerebral ischaemia.
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PMID:Lyme disease presenting as a stroke in the vertebrobasilar territory: MRI. 823 82

In this review, the clinical utility of echoplanar techniques in MRI of the brain is discussed. Comparison of high-resolution EPI with SE/turbo-SE shows high image quality of EPI in the supratentorial brain. In the infratentorial region, however, susceptibility artifacts limit image quality. For the assessment of neuronal brain activation utilizing the intrinsic contrast of blood (BOLD), EPI has definite advantages over other techniques of functional MRI. Due to its superior temporal resolution and multislice capabilities, EPI allows for analysis of complex neuronal activation patterns. Diffusion imaging benefits from the lack of bulk motion artifacts and serves primarily to detect early stroke. Three methods of perfusion imaging (rel. blood volume, rel. blood flow) are discussed: the susceptibility artifact method (T2*), the relaxitivity method (T1), and the signal-labelling technique (STAR). Perfusion imaging may have a clinical impact in the assessment of brain tumors and cerebral ischemia.
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PMID:[Echo-planar imaging of the brain]. 858 33

Focal cerebral ischaemia was produced in 11 rats by permanent occlusion of the right middle cerebral artery (MCA) using a suture model modified to enable manipulation with the animals in situ in an NMR spectrometer. The development of the ischaemic insults and the resultant infarcts were observed for up to 6 h by localized 1H MRS and diffusion-weighted MRI while performing continuous monitoring of electroencephalogram and extracellular DC potential. The ischaemic areas were depicted as regions of hyperintensity in the diffusion-weighted images. Signals due to lactate became visible in the 1H spectra after MCA occlusion indicating the onset of anaerobic glycolysis. A depletion of N-acetylaspartate was seen in all animals post-occlusion. Transient or stepwise increases of lactate were observed to occur coincidentally with the events of spontaneous transient peri-infarct depolarization detected by the electrophysiological measurements. Expansion of the ischaemic area delineated in the diffusion-weighted images also accompanied peri-infarct depolarizations. These observations are consistent with transient peri-infarct depolarization playing a role in the growth of infarcts.
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PMID:Evolution of acute focal cerebral ischaemia in rats observed by localized 1H MRS, diffusion-weighted MRI, and electrophysiological monitoring. 866 6

Our purpose was to review the incidence of negative cerebral panangiography in acute nontraumatic subarachnoid haemorrhage (SAH); to document the amount and distribution of subarachnoid blood on CT and determine its relationship to findings on repeat angiography; and to study the outcome of these patients from the time of presentation to hospital discharge. From 1983 to 1992, 295 patients underwent cerebral angiography for acute SAH at our institution. The CT, angiographic and MRI findings and clinical course of patients with initially negative angiograms were reviewed retrospectively. The overall incidence of negative cerebral panangiography was 31% (92/295). An aneurysm was disclosed on a second angiogram in 4 cases, and on a third angiogram in 1, giving a total false negative rate of 5%. In 55% of cases, only a small amount of SAH was present on CT. The distribution of the subarachnoid blood was nonspecific and resembled the pattern seen in aneurysmal SAH. Ninety-four percent of the patients presented in Hunt-Hess grades I and II. The complications of conservative treatment were few: a rebleed rate of 4%, delayed cerebral ischemia in 4%, cerebral infarcts in 8% and hydrocephalus requiring shunting in 3%. On discharge, 93% of patients had recovered completely and the others were left with moderate disability. There were two deaths related to massive rebleeding. Patients with perimesencephalic SAH (35%) fared particularly well; none developed complications during their hospital stay and repeat angiograms never revealed an underlying aneurysm. In such cases, further angiographic investigations do not seem warranted.
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PMID:The negative angiogram in subarachnoid haemorrhage. 877 68

To obtain a better understanding of the mechanisms underlying early changes in the brain water apparent diffusion coefficient (ADC) observed in cerebral ischemia, dynamic changes in the ADC of water and in the energy status were measured at postnatal day 8 or 9 in neonatal rat brains after cardiac arrest using 1H MRS/MRI and 31P MRS, respectively. The time courses of the MR parameters were compared with changes in the extracellular space (ECS) volume fraction (alpha) and tortuosity (lambda), determined from concentration-time profiles of tetramethylammonium applied by iontophoresis. The data show a decrease of the ADC of tissue water after induction of global ischemia of which the time course strongly correlates with the time course of the decrease in the ECS volume fraction and the increase in ECS tortuosity. This indicates that cell swelling is an important cause for the ADC decrease of water.
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PMID:Dynamic changes in water ADC, energy metabolism, extracellular space volume, and tortuosity in neonatal rat brain during global ischemia. 879 20

This study assessed the sensitivity of contrast-enhanced dynamic echo-planar imaging to subtotal stenosis of the middle cerebral artery as a model of mildly compromised cerebral blood supply. Dynamic data was analyzed in terms of the relative cerebral blood volume (rCBV) and bolus peak arrival time (BPAT), and the prognostic utility of these parameters was compared with measurements of the regional apparent diffusion coefficient of water (ADC) with the goal of identifying tissue at risk of future infarct. Dynamic echo-planar MRI in conjunction with bolus administration of a magnetic susceptibility contrast agent was used in a cat model of acute, unilateral cerebral ischemia, induced by partial occlusion (stenosis) of the right middle cerebral artery. The contrast agent transit was analyzed in terms of the regional time of arrival of the peak bolus-induced signal loss as well as the time integral of agent concentration. Pixel-by-pixel maps of cerebrovascular parameters (rCBV, BPAT) were constructed along with spatial maps of the ADC, derived from diffusion-weighted MR images at the same anatomical level. Arterial stenosis was maintained for a 6 h period, after which histological determination of tissue viability was obtained. Maps of BPAT showed sensitivity to mild flow perturbations not detectable from cerebral blood volume estimations from the same bolus injection or from determinations of the apparent diffusion coefficient of water. Of nine animals subjected to subtotal stenosis, BPAT identified compromised tissue in all nine after 1 h of stenosis. No animals had differences in rCBV or ADC at this point. Stenosis was maintained for 6 h in 7 of the cats. After 6 h, two cats had developed identifiable injury on ADC and rCBV maps. Of the remaining five, where rCBV and ADC appeared normal even after 6 h, three exhibited abnormal histological staining, whereas two indeed appeared normal. In the other two cats where initial subtotal stenosis was later made total, the anatomical region identified as "compromised" during stenosis, by the appearance of delayed bolus peak arrival, matched the area of subsequent infarct after total occlusion of the same vessel. Echo planar imaging in conjunction with bolus administration of a magnetic susceptibility contrast agent appears sensitive to mild perturbations to blood supply. These perturbations may not be resolved on synthesized maps of relative cerebral blood volume or apparent diffusion coefficient. Although "compromised" blood supply does not necessarily lead to infarct (over the 6-h course of this study), it may represent tissue particularly at risk of infarct in the event of further insult.
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PMID:Sensitivity of high-speed "perfusion-sensitive" magnetic resonance imaging to mild cerebral ischemia. 893 28


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