Brain perfusion imaging by arterial spin labeling predicts postsurgical seizure freedom in pediatric focal lesional epilepsy: A pilot study.

Objective: This study was undertaken to determine whether integrating arterial spin labeling (ASL) perfusion imaging into presurgical planning improves postsurgical seizure outcomes in children with pharmacoresistant focal lesional epilepsy associated with focal cortical dysplasia (FCD) or low-grade epilepsy-associated tumors (LEATs).

Methods: We retrospectively analyzed magnetic resonance imaging (MRI) scans from 18 children (median age = 4.8 years, interquartile range = 1.9-11.5) who underwent resection for FCD- or LEAT-associated pharmacoresistant epilepsy, with at least 1 year of follow-up. All patients underwent presurgical ASL imaging along with pre- and postsurgical structural MRI. Image postprocessing, including segmentation and coregistration, assessed the completeness of resection of the anatomical lesion and ASL-derived perfusion changes. DICE similarity scores measured the alignment of pre- to postsurgical segmentations, and the residue ratio assessed the percentage of presurgical segmentation remaining postresection. These metrics were then correlated with postsurgical seizure outcomes.

Results: Fourteen (78%) patients achieved seizure freedom, and 13 (72%) had complete lesion resection. Qualitative analysis showed that complete inclusion of the perfusion changes within the resection cavity significantly correlated with seizure freedom (p = .009), whereas complete resection of the anatomical lesion did not (p = .57). Quantitative analysis indicated that higher alignment of the perfusion changes with the resection cavity, measured by the DICE score, was significantly associated with seizure freedom (p = .043), whereas alignment between lesion and resection was not (p = .44). Larger residual perfusion volumes significantly correlated with seizure recurrence (p = .008).

Significance: Incorporating ASL perfusion imaging into presurgical evaluation may better delineate the epileptogenic zone, potentially improving postsurgical seizure outcomes. These findings support ASL as a valuable complementary tool in surgical planning for pharmacoresistant pediatric focal lesional epilepsy.