Perfusion recovery on TTP maps after endovascular stroke treatment might predict favorable neurological outcomes

Objectives Early recanalization and adequate collateral blood flow are surrogates for functional recovery in endovascular stroke treatment (EVT). We evaluated the prognostic value of pre- and immediate post-thrombectomy perfusion-weighted magnetic resonance imaging (PWI) parameters. Methods Consecutive patients with acute ischemic stroke who underwent EVT were enrolled. Lesion volumes and their corresponding changes on diffusion-weighted (DWI) and PWI were assessed. Outcome was measured with modified Rankin Scale (mRS) at 90 days, and early neurological improvement ( > 8 points improvement on National Institutes of Health Stroke Scale [NIHSS] or 0 to 1) at 7 days. Results Fifty-two patients were enrolled. After control of initial NIHSS and recanalization status, post-thrombectomy time-to-peak (TTP) hypoperfused volume and TTP hypoperfused volume change remained independent predictors of favorable functional outcome (odds ratio [OR] = 0.13, 95% confidence interval [CI] = 0.03–0.54, p = 0.005; OR = 1.018, 95% CI = 1.00–1.03, p = 0.017), and early neurological improvement (OR = 0.20, 95% CI 0.07–0.58, p = 0.003; OR = 1.02, 95% CI = 1.00–1.03, p = 0.010). The areas under the curve of post-thrombectomy TTP hypoperfused volume and TTP hypoperfused volume change were 0.90 and 0.82 (cutoff 68 mL and 56 mL) for favorable outcome and 0.86 and 0.82 (cutoff 76 mL and 58 mL) for early neurological improvement, which had better prognostic values than other MR parameters and recanalization grades. Conclusions These results suggest a large amount of perfusion recovery on TTP is associated with favorable outcome as well as early neurological improvement after EVT, and may be a useful prognostic marker. Key Points • A large amount of perfusion recovery on TTP map is associated with favorable outcome and early neurological improvement after EVT. • The best cutoff value for favorable functional outcome was 68 mL for post-EVT TTP hypoperfused volume and 56 mL decrease for TTP hypoperfused volume. • Amount of perfusion recovery on TTP map has better performance on the prediction of favorable functional recovery and early neurological improvement than other diffusion- and perfusion-weighted MRI parameters and recanalization grades.