Visualization of super-selective Wada with computed tomography perfusion: toward a novel option in preoperative functional mapping

Introduction The Wada test has long been a well-established method for evaluating hemispheric dominance and functional localization; however, it has not been established as a visualizable functional imaging modality. Recently, the super-selective Wada test (ssWada) has emerged as a technique enabling more localized functional evaluation. By selectively catheterizing distal cerebral arterial branches, ssWada enables territory-based functional evaluation with higher spatial resolution than conventional approaches. In this study, we combined ssWada with computed tomography perfusion (CTP) to visualize pharmacologically inactivated brain regions preoperatively. These data were further fused with magnetic resonance imaging (MRI) and CT to propose a novel functional mapping approach delineating the relationship between perfusion-defined functional territories, lesions, and seizure onset zone (SOZ)-related stereoelectroencephalography (SEEG) contacts. Methods Patients who underwent ssWada for preoperative evaluation of brain tumors or drug-resistant epilepsy at our institution were included. During ssWada, propofol was selectively injected via a microcatheter into the ICA and distal branches of the middle cerebral artery (MCA), as well as the anterior or posterior cerebral artery when necessary. Perfusion territories were simultaneously visualized using CTP. These datasets were subsequently fused with MRI and post-SEEG CT to evaluate the spatial relationship between perfusion-defined functional territories, lesions, and SOZ-related SEEG contacts. Results Among the 23 patients, hemispheric dominance was left in 18 patients (78.3%), bilateral in 3 (13.0%), and right in 2 (8.7%). No complications were observed. In the MCA superior trunk territory, repetition, naming, and reading tasks showed positive rates of approximately 70%. In contrast, in the inferior trunk territory, repetition and reading demonstrated high positive rates (93.8%), whereas naming positivity was lower (56.3%). Fusion with MRI and post-SEEG CT enabled spatial visualization of lesions and SOZ-related SEEG contacts within perfusion-defined functional territories, facilitating individualized functional-anatomical assessment for surgical planning. Discussion ssWada combined with CTP enables territory-based visualization of pharmacologically inactivated brain regions and provides a novel preoperative functional mapping approach with high spatial resolution. Fusion with MRI and post-SEEG CT further facilitates individualized functional-anatomical assessment of lesions and SOZ-related networks. These findings support the clinical utility of ssWada-CTP fusion imaging as a novel strategy for individualized preoperative functional brain mapping.