P13.13.B IMPACT OF PREOPERATIVE SOMATOSTATIN-RECEPTOR-TARGETED PET IMAGING ON RESECTION PLANNING AND SURGICAL DECISION-MAKING IN MENINGIOMAS

Abstract BACKGROUND In meningiomas, preoperative MRI remains the primary imaging modality for resection planning, often complemented by CT imaging for skull base or intraosseous tumors. However, the advent of somatostatin-receptor (SSTR)-targeted PET promises significant advantages for delineating tumor boundaries. This study aims to investigate if inclusion of preoperative PET information to conventional MRI/CT influences resection planning in patients with meningioma. MATERIAL AND METHODS We retrospectively analyzed resection boundaries and parameters relevant for surgical planning including osseous resection in patients with meningioma who underwent preoperative PET imaging, based on suspicion of skull base and/or intraosseous involvement. Initially, the parameters were determined only on preoperative MRI/CT. Subsequently, resection planning was re-evaluated using the additional information provided by PET imaging. Imaging analyses were conducted using Brainlab Elements software. RESULTS 50 patients met the inclusion criteria: 29 skull base, 12 convexity and 9 parafalcine meningiomas were identified. The extent of planned tumor resection was modified in the majority of cases (30/50, 60%) after re-evaluating surgical planning with PET imaging. In these patients, planned tumor volumes were mainly altered in meningiomas located at the skull base (19/30, 63.3%), and in tumors with intraosseous involvement (27/30, 90.0%). In detail, in 25/30 patients (83.3%) planned tumor volume increased while it decreased in 5/30 cases (16.6%). Across all patients, median tumor volumes showed an increase after reviewing PET imaging of 0.35 cm³ (p = 0.0001). PET imaging identified the need for further tumor resection to achieve complete resection (Simpson grade 1) in 6/50 patients (12%), who were initially considered completely resectable using MRI/CT-based planning. CONCLUSION Our study shows that preoperative PET imaging may significantly adjust and extend resection boundaries in meningiomas, particularly in cases of skull base and intraosseous meningiomas. Our data highlights the potential limitation of MRI/CT-based planning alone, which may result in an incomplete resection plan. These findings suggest that PET imaging serves as a promising preoperative diagnostic tool that could enhance surgical precision in meningioma surgery, particularly in complex meningioma cases. Whether integrating PET into the standard preoperative evaluation improves patient outcomes should be addressed in future studies.