The time of onset for acute ischemic stroke is unknown. Thus, the MR-based DWI and FLAIR help to estimate the age of lesion for intravenous thrombolysis. CT-based NWU is a potential alternative. This study aims to compare MRI and CT-based NWU for lesion age less than 4.5 hours from onset.

50 individuals with acute anterior circulation stroke are the subjects for the study. The subjects underwent the two imaging modalities at 0.5 and 8 hours after the symptoms. The team rated the DWI-FLAIR lesion mismatch and measured NWU in CT. The NWU and Multiparametric MRI signals were analyzed using logistic regression.

The difference between CT and MRI median time was 35 minutes. The DWI-FLAIR mismatch accuracy was 68.8%. The NWU threshold accuracy was 86%.AUC for MRI was 0.86 and 0.91 in NWU. In the case of wake-up stroke, 53% of patients showed lower NWU – less than 11.5%.

The CT-based imaging’s predictive power is comparable to DWI-FLAIR MRI. A considerable number of subjects with wake-up stroke showed lower NWU and might be best suited for thrombolysis. The study also implies the cons of visual MR rating. Further analysis is essential to encourage CT-based NMU as a widespread alternative.