scholarly journals Separating changes in the intra- and extracellular water apparent diffusion coefficient following focal cerebral ischemia in the rat brain

2002 ◽  
Vol 48 (5) ◽  
pp. 826-837 ◽  
Author(s):  
Matthew D. Silva ◽  
Tsuyoshi Omae ◽  
Karl G. Helmer ◽  
Fuhai Li ◽  
Marc Fisher ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Cerebral Ischemia ◽  
Apparent Diffusion Coefficient ◽  
Rat Brain ◽  
Focal Cerebral Ischemia ◽  
Extracellular Water ◽  
Apparent Diffusion

scholarly journals Secondary Deterioration of Apparent Diffusion Coefficient After 1-Hour Transient Focal Cerebral Ischemia in Rats

2000 ◽  
Vol 20 (10) ◽  
pp. 1474-1482 ◽  
Author(s):  
Laszlo Olah ◽  
Stefan Wecker ◽  
Mathias Hoehn
Keyword(s):  
Diffusion Coefficient ◽  
Energy Metabolism ◽  
Cerebral Ischemia ◽  
Apparent Diffusion Coefficient ◽  
Focal Cerebral Ischemia ◽  
Lesion Volume ◽  
Ischemic Lesion ◽  
Early Reperfusion ◽  
Transient Focal Cerebral Ischemia ◽  
Apparent Diffusion

Recent investigations on transient focal cerebral ischemia suggested recovery of energy metabolism during early reperfusion, but followed by secondary energy failure. As disturbances of energy metabolism are reflected by changes of the apparent diffusion coefficient (ADC) of water, the aim of the current study was to follow the dynamics of the ADC during 1 hour of middle cerebral artery occlusion (MCAO) and 10 hours of reperfusion. The right MCA was occluded in male Wistar rats inside the magnet using a remotely controlled thread occlusion model. Diffusion-, perfusion-, and T2-weighted images were performed repetitively, and ADC, perfusion, and T2maps were calculated and normalized to the respective preischemic value. The lesion volume at each time point was defined by ADC < 80% of control. At the end of 1-hour MCAO the hemispheric lesion volume was 22.3 ± 9.0%; it decreased to 6.4 ± 5.7% in the first 2 hours of reperfusion ( P < 0.01), but then increased again, and by the end of 10 hours of reperfusion reached 17.3 ± 9.3%. The mean relative ADC in the end ischemic lesion volume significantly improved within 2 hours of reperfusion (from 65.7 ± 1.2% to 90.1 ± 6.7% of control), but later declined and decreased to 75.4 ± 7.3% of control by the end of the experiment. Pixels with secondary deterioration of ADC showed a continuous increase of T2value during the first 2 hours of reperfusion in spite of ADC improvement, indicating improving cytotoxic, but generation of vasogenic edema during early reperfusion. A significant decrease of the perfusion level was not observed during 10 hours of recirculation. The authors conclude that the improvement of ADC in the early phase of reperfusion may be followed by secondary deterioration that was not caused by delayed hypoperfusion.

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