Arterial Spin Labeling-Derived Fractional Tumor Burden as a Primary Biomarker for Differentiating Recurrent Tumor from Radiation Necrosis After Stereotactic Radiosurgery.

Secondary arterial spin labeling-derived metrics demonstrated comparable performance (area under the curves = 0.79-0.83).

Normalized fractional tumor burden-high significantly outperformed delta T1 (change in area under the curve = 0.19; 95% CI 0.05-0.31; P = 0.004).

Logistic regression confirmed a monotonic association between normalized fractional tumor burden-high and tumor probability (OR = 1.62 per 10% increase; 95% CI 1.33-2.38; P = 0.001).