Amide proton transfer MRI may reflect effective reperfusion and predict functional outcomes in patients with ischemic stroke

Abstract

Perfusion imaging is useful to assess tissue recovery in patients with acute ischemic stroke (AIS); however, it cannot reflect tissue metabolism. We postulated that amide proton transfer (APT) imaging can characterize the tissue status after reperfusion therapy, thus providing prognostic value for 90-day functional outcomes. We included 63 patients with AIS and large-vessel occlusion (LVO). The APT signals, including APT^# and NOE^# (nuclear Overhauser enhancement) were quantified. Ischemic lesions observed on APT^# and diffusion-weighted imaging (DWI) were classified according to their mismatch patterns (APT^# < DWI; APT^# ≥ DWI). Predictors of 90-day good outcomes (modified Rankin scale score 0–2) were evaluated. Patients with successful reperfusion exhibited higher APT^#, smaller percentage change of APT^#, and a greater likelihood of presenting APT^# < DWI compared to those with poor reperfusion (all P < 0.05). The APT^# (odds ratio [OR] = 11.48, P = 0.046) and a mismatch pattern of APT^# < DWI (OR = 7.41, P = 0.020) independently predicted good outcomes besides the clinical parameters. A mismatch pattern of APT^# ≥ DWI was a significant marker of poor outcomes despite successful reperfusion (P = 0.002). Our study provides preliminary evidence that APT may reveal tissue recovery after reperfusion and predict good outcomes at 90 days in patients with AIS and LVO.