Objective: To examine the impact of corticospinal tract (CST) involvement in acute ischemic stroke patients on functional outcome and the interaction with reperfusion.
Methods: We retrospectively examined clinical and imaging data in consecutive anterior circulation ischemic stroke patients undergoing thrombolysis. MRI perfusion (time to maximum of tissue residue function, Tmax) and apparent diffusion coefficient (ADC) images were transformed into standard space and the volumes of CST involvement by Tmax > 6s (CST-Tmax) and ADC < 600х10-6 mm2/s (CST-ADC) lesions were calculated. Good outcome was defined as modified Rankin Scale ≤ 2 at 3 months. Reperfusion was defined as a reduction in Tmax > 6s lesion volume of ≥ 70% between baseline and 24 hours.
Results: A total of 82 patients were included. Binary logistic regression revealed that both CST-Tmax volume (odds ratio, 1.4, p = 0.008) and CST-ADC volume (odds ratio, 4.9, p = 0.002) at baseline were significantly associated with poor outcome. The 24-hour CST-ADC volume was correlated with baseline CST-ADC volume in patients with reperfusion (r = 0.79, p < 0.001) and with baseline CST-Tmax volume in patients without reperfusion (r = 0.67, p < 0.001). In patients with CST-Tmax volume > 0 mL and CST-ADC volume < 3 mL, the rate of good outcome was higher in patients with reperfusion than those without (70.4% vs 38.1%, p=0.04).
Interpretation: The use of CST-Tmax in combination with CST-ADC provides prognostic information beyond that provided by mismatch volumes in patients considered for reperfusion therapies.