Utility of 68Ga-DOTATATE PET-MRI for Gamma Knife® stereotactic radiosurgery treatment planning for meningioma.

Objectives To investigate the impact of adding ⁶⁸Ga-DOTATATE PET/MRI to standard MRI for target volume delineation in Gamma Knife^® stereotactic radiosurgery (GKSRS) for meningioma. Methods Seventeen patients with 18 lesions undergoing GKSRS for WHO grade 1 meningioma were enrolled in a prospective study. All patients underwent pre-treatment ⁶⁸Ga-DOTATATE PET/MRI examination in addition to standard procedures. Five clinicians independently contoured the gross tumour volume (GTV) based on standard MRI (GTV_MRI) and PET/MRI (GTV_PET/MRI) on separate occasions. Interobserver agreement was evaluated using Cohen's Kappa statistic (CKS), Dice similarity coefficient (DC), and Hausdorff distance (HD). Statistical analysis was performed with paired t -test and Wilcoxon signed rank test. Results The addition of PET/MRI significantly increased GTV contour volume (mean GTV_PET/MRI 3.59 cm³ versus mean GTV_MRI 3.18 cm³, P  = .008). Using the treating clinician's pre-treatment GTV_MRI as the reference, median CKS (87.2 vs 77.5, P  = .006) and DC (87.2 vs 77.4, P  = .006) were significantly lower, and median HD (25.2 vs 31.0, P  = .001) was significantly higher with the addition of PET/MRI. No significant difference was observed in interobserver contouring reproducibility between GTV_MRI and GTV_PET/MRI. Conclusion The addition of ⁶⁸Ga-DOTATATE PET/MRI for target volume delineation in GKSRS for meningioma is associated with an increase in GTV volume and greater interobserver variation. PET/MRI did not affect interobserver contouring reproducibility. Advances in Knowledge This study provides novel insights into the impact of ⁶⁸Ga-DOTATATE PET/MRI on GTV delineation and interobserver agreement in meningioma GKSRS, highlighting its potential for improving GKSRS treatment accuracy. [ABSTRACT FROM AUTHOR]