摘要:

Abstract not available.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Abstract not available.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Abstract not available.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

True three-dimensional proton nuclear magnetic resonance (NMR) imaging was performed on an 84-year-old man following a recent cerebral embolic infarction. NMR data obtained using different pulse sequences were inter-correlated, stressing the significance of image appearance in terms of the NMR tissue parameters. Planes selected for display from the three-dimensional data set allowed optimal visualization of the pathology. Accurate correlations of the NMR data with X-ray computerized tomography scans and with subsequent autopsy findings indicate that NMR may play an important role in the detection and diagnosis of ischemic stroke.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Proton nuclear magnetic resonance (NMR) images depict the distribution and concentration of mobile protons modified by the relaxation times T1 and T2. Using the steady-state-free-precession (SSFP) technique, serial coronal images were obtained sequentially over time in laboratory animals with experimental ischemic infarction. Image changes were evident as early as 2 hours after carotid artery ligation, and corresponded to areas of ischemic infarction noted pathologically. Resulting SSFP images in experimental stroke are contrasted to inversion-recovery NMR images in an illustrative patient with established cerebral infarction. Bulk T1 and T2 measurements were made in vitro in three groups of gerbils: normal, those with clinical evidence of infarction, and those clinically normal after carotid ligature. Infarcted hemispheres had significantly prolonged T1 and T2 (1.47 +/− .12 sec, 76.0 +/− 9.0 msec, respectively) when compared to the contralateral hemisphere (T1 = 1.28 +/− .05 sec, T2 = 58.7 +/− 3.9 msec) or to the other two groups. These data suggest that changes in NMR parameters occur and can be detected by NMR imaging as early as two hours after carotid artery ligation.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Advancements in computer science and magnet design have resulted in the recent development of high resolution NMR imaging systems. Using our primate model we evaluated the ability of NMR scanning to detect early changes following middle cerebral artery (MCA) occlusion. Serial NMR scans documented progressive changes secondary to edema and swelling beginning ninety minutes after MCA occlusion. NMR was also able to readily demonstrate the area of cerebral infarct 10 days after a six hour episode of MCA occlusion. Soft tissue contrast and image resolution were superb. Correlation with pathologic sections was excellent.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Two experiments were done with a prototype mini-NMR imager to evaluate the potential application of nuclear magnetic resonance (NMR) imaging in neuropathology. Cryo-injury-induced brain edema in brain slices from 22 adult male rats was imaged for observing the chronological sequences. Blood-brain barrier permeability changes were evaluated in 12 other brain slice images. EDTA-2Na-Mn solution was intravenously injected as an indicator of blood-brain barrier permeability. Contrast enhancement was achieved by changing the NMR imaging parameters. High resolution imaging permitted visualization of the corpus callosum, the thickness of which was only 0.2-0.4 mm. The extent of edema in gray matter was clearly shown with a striking contrast; no consistent findings were seen with slight differences in water content between edema and the surrounding normal cortex. As a result, the chronological sequences of brain edema were clearly observed. Mn-EDTA leaking from the circulating blood through the damaged capillary wall had a “paradoxical enhancement” effect on the NMR images; this effect might be suitable for evaluating blood-brain barrier permeability changes in NMR images.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

Ten patients with ischaemic stroke were treated with prostacyclin (2.5-5.0 ng/kg/min i.v. in 6 h courses 4-10 times during 1-2.5 days). In all patients a dramatic regression of hemiplegia, or hemiparesis, or aphasia occurred in the first few hours of prostacyclin infusion. Four to eight weeks later 6 patients left the clinic without neurological deficit; 3 patients had minor residual hemiparesis in upper limbs. In one patient, the occlusion of the contralateral carotid artery led to his death. It is considered that an antagonism may exist between endogenous cerebral prostanoids and prostacyclin and may have been responsible for the beneficial effects of prostacyclin therapy.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

The object of this investigation was to study the effects of prostacyclin (PGI2) upon the evolution of acute focal cerebral ischemia in the cat. Twenty-five fasted adult cats, lightly anesthetized with nitrous oxide, underwent right middle cerebral artery (MCA) occlusion. Eleven cats received an intracarotid infusion of PGI2 in buffered saline pH 10.5 (100 ng/kg/min at 0.01 ml/kg/min), and 11 cats received intracarotid buffered saline pH 10.5 (0.01 ml/kg/min) without therapeutic agents. Treatment with PGI2 was started upon MCA occlusion and continued for 6 hours. Thirty minutes prior to perfusion, the animals were given fluorescein and Evans blue by intravenous injection. The cats were perfused-fixed in vivo with carbon and buffered formalin 6 hours after MCA occlusion. Another 3 cats received tritium labeled intracarotid PGI2, and peripheral venous samples were collected and assayed for PGI2 plasma levels. Mean arterial pressure was stable in PGI2 treated animals during 6 hours of MCA occlusion, while untreated cats had significant progressive hypertension during that period. The rCBF (measured by the intracarotid 133Xe method) decreased markedly in all animals immediately upon MCA occlusion. However, untreated animals had a significant progressive improvement in rCBF during the occlusion period, while PGI2 treated animals had no such improvement. Quantitative EEG changes, gross edema, areas of fluorescein extravasation, patterns of carbon perfusion, and infarct size were not significantly different in the two groups. While most untreated animals had marked Evans blue extravasation after 6 hours of MCA occlusion, most PGI2 treated animals had no such extravasation, indicating some protection of the blood-brain barrier in these animals.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID

摘要:

In previous experimental work, the Ca-antagonist Nimodipine had shown a predominantly cerebroarterial dilatory effect. In the present double-blind study of 16 patients, pial arterial and venous reaction was investigated during EC-IC bypass surgery, infusing 1 microgram kg-1min-1 of Nimodipine intravenously. In pial arteries with resting diameters between 25 and 70 micrometers, a significant 18% dilatation was observed. Results are considered promising for future trials in the treatment and prevention of cerebral ischemia caused by vasoconstriction or vasospasm, especially vasospasm following subarachnoid hemorrhage.

ISSN:0039-2499    

出版商:OVID    

年代:1983

数据来源: OVID