Figure 3. Structural Equation Models Including Different Latent Variables as Possible Mediator.

Each causal hypothesis diagram includes a latent variable (brain frailty) as a possible mediator for the association of chronological age and 90-day functional outcome. Each model includes a different latent variable: imaging measures of brain frailty (A) and a total construct of brain frailty (B). Adjustments for all models were made for the administration of nerinetide and/or alteplase, onset-to-puncture time, National Institutes of Health Stroke Scale at baseline, and Alberta Stroke Program Early Computed Tomography Score at baseline. Rectangles represent observed variables; ovals represent latent variables. Linear equations are built by using arrows between the variables; 90-day functional outcome was included as an ordinal variable following the full categorical scale (ie, modified Rankin Scale [mRS] scale, which ranges from 0 to 6, with 0 indicating perfect health without symptoms and 6 indicating death).