Effect of Gd-DTPA on Diffusion in Canine Brain with Hyperacute Stroke

Kim, Bum Soo; Jung, So Lyung; Shin, Kyung Sub

Abstract

PURPOSE: To evaluate the effect of Gd-DTPA on signal intensity of diffusion-weighted magnetic resonance (MR) image and apparent diffuse coefficient (ADC) in dog brain with hyperacute stroke.
MATERIALS AND METHODS
Experimental canine model of hyperacute cerebral infarction was made by selective intraarterial embolization with particulate embolic material. Diffusion-weighted MR imaging was performed in five dogs at 1 hour after the embolization of internal carotid artery. After intravenous bolus injection of Gd-DTPA, additional 11 diffusion-weighted MR images were serially obtained from 2 minutes to 90 minutes after injection in each dog. The author evaluated findings of hyperacute cerebral infarction on diffusion-weighted MR imaging, and calculated mean signal intensity and mean ADC in infarcted region and contralateral normal region. Statistical analysis of mean signal intensity, mean ADC and contrast-noise ratio before and after Gd-DTPA injection was performed.
RESULTS
Hyperacute cerebral infarction developed in all five dogs on diffusion-weighted MR images obtained 1 hour after embolization. The area of hyperacute infarction had steady increase in signal intensity on diffusion-weighted MR image and decrease in ADC. In normal perfusion area, decrease in signal intensity was observed at 2 minutes the Gd-DTPA injection, whereas ADC did not changed.
CONCLUSION
Intravenous injection of Gd-DTPA had no influence on ADC in both hyperacute infarction and normally perfused area, but caused initial transient signal reduction in normally perfused area on diffusion-weighted MR image due to susceptibility effect of Gd-DTPA. It is important to calculate ADC in evaluating the effect of diffusion after injection of Gd-DTPA.