The time threshold to reperfusion for DWI reversal in acute ischemic stroke depends on pre-interventional ADC value

The aims of this study are to explore the apparent diffusion coefficient (ADC)-dependent thresholds for time to reperfusion in reversible lesions following mechanical thrombectomy for acute ischemic stroke, and to investigate the associated risks of hemorrhagic transformation.

We conducted a retrospective case-control study, enrolling patients with large-vessel occlusion who underwent mechanical thrombectomy in Otaru General Hospital from 2016 to 2021. Reversible lesions were identified using volumetric ADC data, and the mean time from image to reperfusion (TIR) in each ADC range was compared between groups with and without reversible lesions, as well as those with and without parenchymal hematoma. The Wilcoxon rank sum test and chi-square test were used for comparison between two groups, and receiver operating characteristic curves were created to determine optimal thresholds.

Seventy-five patients were included and 581 volumetric data were obtained. The mean TIR in the group with reversible lesions was shorter than in that without, and time thresholds were 131, 123 and 112 min for ADC values > 540 × 10^-6, 500-540 × 10^-6 and 440-500 × 10^-6 mm²/s, respectively. Furthermore, in patients with parenchymal hematoma, the mean TIR was significantly longer, and the average ADC value was significantly lower than those without hematoma.

The time thresholds for the irreversible ischemic core may vary depending on the ADC value, and they may be shorter when the ADC value is lower. Moreover, both the low ADC value and the late reperfusion might be associated with an increased risk of parenchymal hematoma.