Perfusion-diffusion mismatch in magnetic resonance imaging (MRI) represents the non-core hypoperfused area
in acute ischemic stroke. The mismatch has been used to predict clinical response after thrombolysis in acute ischemic
stroke, but its role for predicting early neurological deterioration (END) in acute ischemic stroke without thrombolysis has
not been clarified yet. In this study, we prospectively recruited 54 patients with acute non-lacunar ischemic stroke in anterior
circulation without thrombolysis. All patients received the first perfusion MRI within 24 hours from stroke onset.
Target mismatch profile was defined as a perfusion-diffusion mismatch ratio ≥ 1.2. END was defined as an increase of ≥ 4
points in the National Institute of Health Stroke Scale (NIHSS) score within 72 hours. There were 13 (24.1%) patients developing
END, which was associated with larger infarct growth (p = 0.002), worse modified Rankin Scale (p = 0.001) and
higher mortality rate at 3 months (p = 0.025). Target mismatch profiles measured by Tmax ≥ 4, 5 and 6 seconds were independent
predictors for END after correcting initial NIHSS score. Among the 3 Tmax thresholds, target mismatch measured
by Tmax ≥ 6 seconds had the highest odd’s ratio in predicting END (p < 0.01, odd’s ratio = 17), with an 80% sensitivity
and a 79.5% specificity. In conclusion, perfusion-diffusion mismatch could identify the patients at high risk of early clinical
worsening in acute ischemic stroke without thrombolysis.