The apparent diffusion coefficient color Map for evaluating a large ischemic core

Our previous work demonstrated that evaluating large ischemic cores using the apparent diffusion coefficient (ADC) could predict EVT outcomes, with the most frequent ADC (peak ADC) ≥520×10^-6 mm²/s associated with better clinical results. Since the degree of ADC reduction reflects the severity of ischemic stress, this study aimed to assess the utility of an ADC color map in visualizing this stress.

This retrospective cohort study included consecutive patients with a low Alberta Stroke Program Early Computed Tomography Score (ASPECTS) using diffusion-weighted imaging (DWI) who underwent successful EVT recanalization between April 2014 and March 2023. To create a visual representation of ischemic stress, we assigned different colors to diffusion-weighted image (DWI) lesions based on their ADC values: ≥520×10^-6 mm²/s, 520-440×10^-6 mm²/s, and <440×10^-6 mm²/s. We compared patients with peak ADC ≥520×10^-6 mm²/s to those with lower peak ADC to identify factors associated with the higher value.

A total of 78 patients were enrolled, with 34 having a peak ADC ≥520×10^-6 mm²/s. The optimal ratio for discriminating peak ADC ≥520×10^-6 mm²/s was found to be 60 % for the volume of the lesion with ADC ≥520×10^-6 mm²/s (ADC₅₂₀) relative to the total DWI lesion volume. This ratio demonstrated a sensitivity of 86 % and a specificity of 82 %.

The ADC color map effectively portrays the depth of ischemic stress. A large ischemic core with an ADC₅₂₀/DWI ratio >60 % may be salvageable with EVT. This approach offers a visual means for assessing EVT suitability in acute large ischemic stroke.