scholarly journals Diffusion-Weighted Magnetic Resonance Imaging of Acute Focal Cerebral Ischemia: Comparison of Signal Intensity with Changes in Brain Water and Na+,K+ -ATPase Activity

1994 ◽  
Vol 14 (2) ◽  
pp. 332-336 ◽  
Author(s):  
Jan Mintorovitch ◽  
G. Y. Yang ◽  
Hiroaki Shimizu ◽  
John Kucharczyk ◽  
Pak H. Chan ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Magnetic Resonance ◽  
Atpase Activity ◽  
Water Content ◽  
Signal Intensity ◽  
Focal Cerebral Ischemia ◽  
Mr Images ◽  
Diffusion Weighted ◽  
Acute Cerebral Ischemia ◽  
Brain Water

Diffusion-weighted magnetic resonance (MR) images from rats during acute cerebral ischemia induced by middle cerebral artery occlusion were analyzed for correspondence with changes in brain water, cation concentrations, and Na+,K+-ATPase activity measured in vitro after 30 or 60 min of ischemia. In the ischemic hemisphere, signal intensity was increased at 30 min (p < 0.05 vs contralateral hemisphere) and further increased at 60 min. Na+,K+-ATPase activity was 34% lower in ischemic cortex and 40% lower in ischemic basal ganglia after 30 min (p < 0.05), but water content and Na+ and K+ concentrations were not significantly different between hemispheres. After 60 min, water content and Na+ concentration were increased, and both Na+,K+-ATPase activity and K+ concentration were decreased in the ischemic hemisphere (p < 0.05). These findings are consistent with the hypothesis that the early onset of signal hyperintensity in diffusion-weighted MR images may reflect cellular edema associated with impaired membrane pump function. Early in vivo detection and localization of potentially reversible ischemic cerebral edema may have important research and clinical applications.

In vivo diffusion–perfusion magnetic resonance imaging of acute cerebral ischemia

1991 ◽  
Vol 69 (11) ◽  
pp. 1719-1725 ◽  
Author(s):  
John Kucharczyk ◽  
Jan Mintorovitch ◽  
Haleh Asgari ◽  
Mitsuharu Tsuura ◽  
Michael Moseley
Keyword(s):  
Cerebral Ischemia ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
Mr Images ◽  
Ischemic Brain ◽  
Diffusion Weighted ◽  
Acute Cerebral Ischemia ◽  
Planar Images ◽  
Echo Planar

We compared the anatomic extent and severity of ischemic brain injury shown on diffusion-weighted magnetic resonance (MR) images, with cerebral tissue perfusion deficits demonstrated by a nonionic intravascular T2*-shortening magnetic susceptibility contrast agent used in conjunction with standard T2-weighted spin-echo and gradient-echo echo-planar images. Diffusion-weighted images displayed increased signal intensity in the vascular territory of the middle cerebral artery 25–40 min after permanent occlusion, whereas T2-weighted images without contrast were negative or equivocal for at least 2–3 h after stroke was induced. Contrast-enhanced T2-weighted and echo-planar images revealed perfusion deficits that were spatially closely related to the anatomic regions of ischemic tissue injury. These data indicate that diffusion-weighted MR images are very sensitive to early onset pathophysiologic changes induced by acute cerebral ischemia. Combined sequential diffusion–perfusion imaging enables noninvasive in vivo examination of the relationship between hypoperfusion and evolving ischemic brain injury.Key words: in vivo, diffusion, perfusion, acute cerebral ischemia, magnetic resonance imaging.

scholarly journals Quantitation of Photochemically Induced Focal Cerebral Ischemia in the Rat

1988 ◽  
Vol 8 (1) ◽  
pp. 89-95 ◽  
Author(s):  
John J. Grome ◽  
Gerlinde Gojowczyk ◽  
Wolfgang Hofmann ◽  
David I. Graham
Keyword(s):  
Cerebral Ischemia ◽  
Water Content ◽  
Rose Bengal ◽  
Tissue Damage ◽  
Focal Cerebral Ischemia ◽  
Ischemic Damage ◽  
Brain Water Content ◽  
Ischemic Insult ◽  
Ischemic Lesion ◽  
Brain Water

This study was carried out with a recently developed model of focal cerebral ischemia in the rat based on the photochemical induction of thrombotic stroke using the dye Rose Bengal. We examined the change in the volume of the lesion and brain water content, in separate groups of rats, at different times (1, 4, 24, 72, and 168 h) after the induction of the ischemic lesion. The volume of ischemic damage increased rapidly between 1 and 24 h after the ischemic insult and decreased between 24 and 168 h. The lesion at 168 h was significantly larger than that following 1 h of ischemia and similar to that obtained at 4 h, suggesting that the maximum extent of tissue damage (without the involvement of significant edema) was reached within the first 4 h in this model. The enlargement of the lesion after 4 h correlated closely with changes in brain water content.

scholarly journals Polynitroxyl Albumin Reduces Infarct Size in Transient Focal Cerebral Ischemia in the Rat: Potential Mechanisms Studied by Magnetic Resonance Imaging

1998 ◽  
Vol 18 (9) ◽  
pp. 1022-1031 ◽  
Author(s):  
Christian Beaulieu ◽  
Elmar Busch ◽  
Joachim Röther ◽  
Alexander de Crespigny ◽  
Carleton J. C. Hsia ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cerebral Ischemia ◽  
Magnetic Resonance ◽  
Middle Cerebral Artery ◽  
Diffusion Weighted Imaging ◽  
Focal Cerebral Ischemia ◽  
Treated Group ◽  
Resonance Imaging ◽  
Diffusion Weighted ◽  
Transient Focal Cerebral Ischemia

Nitroxide free radicals are known to protect cells from oxidative damage. Diffusion-weighted and perfusion-weighted magnetic resonance imaging was used to evaluate the effects of polynitroxyl albumin(PNA) in a middle cerebral artery intraluminal suture model of transient focal cerebral ischemia in the rat. Three groups of Sprague-Dawley rats were investigated: (1) PNA(N = 6), (2) human serum albumin (N = 6), and (3) saline (N = 7). The middle cerebral artery was occluded for 2 hours. Treatment was started 30 minutes after induction of ischemia. A total dose of 1% body weight (volume/weight) of PNA (23.5 mg/dL protein and 110 mmol/L nitroxide), albumin (23.5 mg/dL), or saline was injected intravenously at three time points: 0.5% at 0.5 hours, 0.25% at 2 hours (i.e., just before reperfusion), and 0.25% at 4 hours after occlusion. Six sets of diffusion- and perfusion-weighted magnetic resonance images were acquired throughout the 2 hours of ischemia and the 2 hours of reperfusion. The rats were killed at 24 hours, and the brains were stained with 2,3,5-triphenyltetrazolium chloride (TTC). Diffusion-weighted imaging showed that the growth of the ischemic lesion was suppressed in the PNA-treated group. The 4 hours diffusion-weighted imaging-derived hemispheric lesion volume in the PNA-treated group (25% ± 9%) was significantly smaller than that in the saline-treated(43% ± 13%; P = 0.016) or albumintreated groups (38% ± 6%; P = 0.017). A larger difference was observed for the 24-hour TTC-derived lesion volumes in the PNA (8% ± 7%), saline (35% ± 8%; P< 0.001), and albumin (31% ± 6%; P < 0.001) groups. Perfusion-weighted imaging demonstrated a marked improvement in cerebral perfusion in the PNA-treated group during ischemia and reperfusion. In conclusion, treatment with PNA results in an improvement in perfusion and a reduction of infarct volume in a model of transient focal cerebral ischemia in the rat.

scholarly journals Neuroprotection of Sanhua Decoction against Focal Cerebral Ischemia/Reperfusion Injury in Rats through a Mechanism Targeting Aquaporin 4

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Lin Lu ◽  
Hui-qin Li ◽  
Ji-huang Li ◽  
Ai-ju Liu ◽  
Guo-qing Zheng
Keyword(s):  
Cerebral Ischemia ◽  
Water Content ◽  
Brain Edema ◽  
Focal Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Aquaporin 4 ◽  
Brain Water Content ◽  
Aqp4 Expression ◽  
Cerebral Ischemia Reperfusion ◽  
Brain Water

Sanhua decoction (SHD) is a famous classic Chinese herbal prescription for ischemic stroke, and aquaporin 4 (AQP4) is reported to play a key role in ischemic brain edema. This study aimed to investigate neuroprotection of SHD against focal cerebral ischemia/reperfusion (I/R) injury in rats and explore the hypothesis that AQP4 probably is the target of SHD neuroprotection against I/R rats. Lentiviral-mediated AQP4-siRNA was inducted into adult male Sprague-Dawley rats via intracerebroventricular injection. The focal cerebral ischemia/reperfusion model was established by occluding middle cerebral artery. Neurological examinations were performed according to Longa Scale. Brain water content, was determined by wet and dry weight measurement. Western blot was adopted to test the AQP4 expression in ipsilateral hippocampus. After the treatment, SHD alleviated neurological deficits, reduced brain water content and downregulated the expression of AQP4 at different time points following I/R injury. Furthermore, neurobehavioral function and brain edema after I/R were significantly attenuated via downregulation of AQP4 expression when combined with AQP4-siRNA technology. In conclusion, SHD exerted neuroprotection against focal cerebral I/R injury in rats mainly through a mechanism targeting AQP4.

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