ADC Threshold Indicating the Ischemic Region for Predicting Efficacy in Thrombectomy

The effectiveness of endovascular thrombectomy (EVT) has been proven in patients with large cerebral infarction. However, the size of the ischemic region before treatment is a significant factor in the outcome, and the optimal method for the evaluation of this region is uncertain. The goal of this study was to investigate apparent diffusion coefficient (ADC) values as a basis for an assessment of the ischemic region before treatment.

A retrospective study was performed in 48 consecutive patients who underwent EVT for acute large vessel occlusion (LVO) with Alberta Stroke Program Early Computed Tomography Score (ASPECTS) ≤5 from 2014 to 2022. Associations of clinical characteristics and ADC-related ischemic region volumes with a favorable outcome (modified Rankin Scale (mRS) 0-3 at 90 days) were examined.

The 48 patients had a median age of 78 years and a median NIHSS score of 23 at admission. Occlusion sites were the internal carotid artery (46%), M1 segment (46%), and M2 segment (8%). Specifically, 18 cases (38%) were mRS 0-3 and 30 (62%) mRS 4-6 at 90 days. In receiver operating characteristic (ROC) analysis, an ischemic region defined as a volume with an ADC < 540 (ADC₅₄₀) had the highest area under the curve (AUC) value (AUC = 0.85). Multivariate analysis showed independent associations between onset to reperfusion time (OR 0.991, 95% CI 0.981-1.000, p = 0.013) and ADC₅₄₀ (OR 0.887, 95% CI 0.807-0.976, p = 0.001) with mRS 0-3 at 90 days.

Earlier reperfusion and a smaller ischemic region defined by ADC₅₄₀ were related to a favorable outcome in patients with acute LVO with a large ischemic region.