Predicting lesion reversal in acute cerebral ischaemia via apparent diffusion coefficient threshold on...

Area of Science:

• Neuroimaging
• Stroke research
• Medical diagnostics

Background:

• Diffusion-weighted imaging (DWI) detects early ischemic changes but cannot definitively distinguish reversible from irreversible tissue damage.
• Apparent diffusion coefficient (ADC) thresholds are proposed to differentiate salvageable brain tissue from irreversibly damaged areas.
• Diffusion-weighted imaging lesion reversal (DWI-R) highlights the dynamic nature of ischemic injury and the potential for tissue salvage.

Purpose of the Study:

• To evaluate the predictive value of a single apparent diffusion coefficient (ADC) threshold for diffusion-weighted imaging lesion reversal (DWI-R).
• To assess the accuracy of ADC thresholds in distinguishing salvageable from irreversibly damaged tissue following successful recanalization.
• To investigate the utility of voxel-level ADC analysis in predicting tissue viability in acute ischemic stroke.

Main Methods:

• Retrospective cohort study analyzing patients who underwent DWI before and after endovascular therapy with successful recanalization within 120 minutes.
• Voxel-wise assessment of DWI-R for ADC values within a defined range (200–760 × 10⁻⁶ mm²/s).
• Receiver operating characteristic (ROC) analyses were used to evaluate the predictive accuracy of ADC thresholds.

Main Results:

• The study included 71 patients with a mean baseline DWI lesion volume of 18.13 mL.
• An optimal ADC threshold of 555 × 10⁻⁶ mm²/s showed moderate sensitivity (73.8%) and low specificity (58.6%) for predicting DWI-R (AUC = 0.708).
• A significant percentage of voxels (average 37.5%) demonstrated reversal, and even low ADC values showed some degree of reversal, indicating incomplete tissue death.

Conclusions:

• Fixed ADC thresholds have limited utility and modest accuracy in predicting DWI-R and identifying salvageable brain tissue in acute ischemic stroke.
• A single ADC cut-off demonstrates poor specificity for predicting DWI-R, reinforcing concerns about its use in defining irreversible injury.
• The findings emphasize the need for caution when excluding patients from recanalization therapy based solely on restrictive diffusion parameters, as no definitive lower ADC boundary reliably predicts the absence of salvageable tissue.