Correlation of the Average Water Diffusion Constant with Cerebral Blood Flow and Ischemic Damage After Transient Middle Cerebral Artery Occlusion in Cats

• Published in: Journal of cerebral blood flow and metabolism Vol. 16; no. 5; pp. 881 - 891
• Main Authors: Miyabe, Masayuki, Mori, Susumu, van Zijl, Peter C. M., Kirsch, Jeffrey R., Eleff, Scott M., Koehler, Raymond C., Traystman, Richard J.
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.09.1996; Lippincott Williams & Wilkins
• Subjects: Animals; Biological and medical sciences; Body Water - metabolism; Cats; Cerebral Arteries; Cerebrovascular Circulation; Coloring Agents; Constriction; Diffusion; Ischemic Attack, Transient - physiopathology; Magnetic Resonance Imaging; Medical sciences; Neurology; Regression Analysis; Reperfusion; Tetrazolium Salts; Vascular diseases and vascular malformations of the nervous system; Transient focal ischemia; Magnetic resonance imaging; Water diffusion tensor trace; Cerebral blood flow; Brain injury; Fissipedia; Animal model; Carnivora; Nervous system diseases; Middle cerebral artery; Cardiovascular disease; Exploration; Nuclear magnetic resonance imaging; Transitory; Cerebral disorder; Arterial disease; Vascular disease; Vertebrata; Experimental disease; Mammalia; Ischemia; Animal; Central nervous system disease; Cat; Obliteration; Diffusion coefficient; Cerebrovascular disease; Brain (vertebrata)
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1097/00004647-199609000-00012

Magnetic resonance water diffusion imaging can detect early ischemic changes in stroke. Using a middle cerebral artery occlusion model, we examined which range of values of the orientation-independent diffusion quantity is an early noninvasive indicator of reduced cerebral perfusion and focal brain injury. Cats underwent either a 30-min occlusion followed by 3.5 h reperfusion (n = 7) or a 60-min occlusion followed by 4-h reperfusion (n = 6). Repeated measurements of CBF were made with radiolabeled microspheres, and acute focal injury was measured with triphenyltetrazolium chloride (TTC) staining. During occlusion, the decrease in Dav correlated with CBF for caudate [30-min occlusion (n = 13): p < 0.0001; 60-min occlusion (n = 6): p < 0.02] and for cortex [30-min occlusion (n = 12): p < 0.0001; 60-min occlusion (n = 5): p < 0.04]. Variable caudate and hemispheric injury levels were found among cats in both groups. The area of tissue injury demarcated by TTC began to correlate with the area of reduced Dav by 30 min of occlusion (p < 0.02), and this correlation improved (p < 0.0001) at 1, 1.5, and 2.0 h after the onset of occlusion. The time necessary to reach a one-to-one correspondence between the percent of hemisphere injured and the percent of hemispheric area with Dav < 0.65 × 10−9 m2/s was 2 h after occlusion. Thus, the absolute value of Dav is a good indicator of the risk of tissue injury, whereas the combination of Dav and the length of time of Dav reduction is an excellent predictor of acute focal tissue injury demarcated by TTC staining.