Background: By recent advance of endovascular thrombectomy, we have often experienced acute ischemic patients who have diffusion weighted imaging (DWI) reversal lesions after earlier successful recanalization. We retrospectively investigated the relationship between apparent diffusion coefficient (ADC) thresholds of tissue infarction and time from onset to recanalization in acute ischemic stroke patients.
Methods: We assessed 24 patients who have occlusion of internal carotid artery (n=11) and the main trunk of middle cerebral artery (n=13) and obtained recanalization of TICI2b (n=12) and TICI3 (n=12) by thrombectomy and performed MRI before and after treatment. Relative ADC (rADC) value were calculated for initial DWI lesions and around hypoperfused regions. We evaluated rADC values in infarcted and non-infarcted area and analyzed the relationship between rADC thresholds of tissue infarction and time.
Results: The mean time from onset to recanalization was 209 minutes and mean initial NIHSS was 15.4. The mean rADC value was 0.633 in infarcted lesions and 0.905 in non-infarcted area (p<0.001). The thresholds for rADC value for infarction by the area under the curve derived from receiver operating characteristic curve analysis were 0.769 in the area which recanalized under 180 minutes form the onset, 0.792 in that from 180 to 240 minutes, and 0.798 in that over 240 minutes.
Conclusion: The estimation of rADC value may be useful in predicting the likelihood of DWI lesion reversal. Marked decreasing of rADC value which is under thresholds of infarction indicated irreversible damage of ischemic tissue regardless of early successful recanalization.