Effect of Intravenous Thrombolysis on the Time Course of the Apparent Diffusion Coefficient in Acute Middle Cerebral Artery Infarction.

Background And Purpose: To examine the possible effects of intravenous thrombolysis on the time course of the apparent diffusion coefficient in the patients with acute middle cerebral artery infarct.

Methods: Serial MRI data with all in all 190 MR examinations including diffusion-weighted imaging (DWI), apparent diffusion coefficient map (ADC map) and T2 -weighted imaging (T2 w) of 74 patients with initial intravenous thrombolysis (study group; N = 37) or conservative stroke treatment (control group; N = 37) were retrospectively analyzed. A trend function was fitted to the relative values (rADC, rDWI, rT2 w) to model an objective, general time course.

Results: Relative apparent diffusion coefficient (rADC) decreased in both groups to a minimum about 15 hours after symptom onset. Afterwards rADC increased faster in the study group and reached pseudonormalization 5 ± 2 days after symptom onset. In the control group pseudonormalization was determined later at 7 ± 6 days after symptom onset. After pseudonormalization rADC continued to increase in both groups.

Conclusion: rADC pseudonormalization occurred by trend earlier in the study group. Therefore, intravenous thrombolysis seems to have an effect on the time course of ADC, which is likely to be due to earlier cerebral reperfusion after thrombolysis. In addition, initial stroke treatment as thrombolysis should be considered in radiological rating of stroke MRI time course.