J Korean Radiol Soc.  2002 Apr;46(4):293-300.

Reversal of Apparent Diffusion Coefficient (ADC) Following Transient Focal Cerebral Ischemia in Cats

Affiliations
  • 1Department of Diagnostic Radiology, Yonsei University Medical College. dikim@yumc.yonsei.ac.kr
  • 2Department of Diagnostic Radiology, Eulji University, School of Medicine.
  • 3Department of Medicine, Yonsei University Medical College.
  • 4Department of Neurology, Yonsei University Medical College.
  • 5Department of Neurosurgery, Yonsei University Medical College.

Abstract

PURPOSE
To determine the minimal threshold ADC ratio suggesting reversible ischemia in a temporary model of MCAO.
MATERIALS AND METHODS
Seven Korean cats weighing 3-3.5 kg were used as a temporary model of MCAO. The MCA was occluded for 1 hour, and diffusion-weighted images (DWI), and ADC and regional cerebral blood volume (rCBV) maps, were obtained at 1, 3, 6 and 24 hours after reperfusion using a 1.5T MR unit. The Cats were sacrificed 24 hours after imaging. Triphenyl tetrazolium chloride (TTC) staining of brain slices was performed, and DWI images and TTC-stained brain slices were compared with the naked eye. Reversible ischemia was defined as the area of high signal intensity at 1-hour DWI that normalized at follow-up DWI and in which TTC staining was normal. Using the ADC image obtained at 1 hour after reperfusion, 60 ADC ratios were obtained in the periphery of the infarct and reversible ischemia. Tissue survival showing normal TTC staining was used for final determination. The sensitivity and specificity of each ADC ratio was obtained and an ROC curve was plotted.
RESULTS
Five of seven cats showed the reversible ischemia. An area of high signal intensity was seen on DWI images obtained 1 hour after reperfusion, and this improved at follow-up imaging. The distribution of the ADC ratio in the periphery of the infarct core was 0.71-0.81, and in the periphery of reversible ischemia it was 0.79-0.93. The ADC ratio of 0.80 obtained 1 hr after reperfusion predicted the survival of the ischemic tissue with 93% sensitivity and 90% specificity. The ADC ratio of the reversible ischemia was 0.82+/-0.03 at 1 hour after reperfusion, and this was higher than that of the infarct, which was 0.74+/-0.03.
CONCLUSION
The minimal threshold ADC ratio suggesting reversible ischemia in this temporary model of MCAO was 0.80.

Keyword

Brain, infarction; Magnetic resonance (MR), experimental; Magnetic resonance (MR), diffusion study

MeSH Terms

Animals
Blood Volume
Brain
Brain Ischemia*
Cats*
Diffusion*
Follow-Up Studies
Ischemia
Reperfusion
ROC Curve
Sensitivity and Specificity
Tissue Survival
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