Dynamic 68Ga-DOTATATE PET/MRI in the Diagnosis and Management of Intracranial Meningiomas

Background: While MRI is the gold standard for meningioma diagnosis and treatment planning, it poses limitations in differentiating residual/recurrent disease from post-treatment-change. 68Ga-DOTATATE PET/MR of 50 min with standardized uptake value (SUV) analysis has demonstrated clinical utility in patients with meningioma. However, SUV is considered semi-quantitative with limited reproducibility depending on several variable parameters not accounted for in its definition. Dynamic PET acquisitions enable parametric imaging accounting for post-injection time to improve quantification. Our purpose was to assess feasibility and clinical utility of dynamic 68Ga-DOTATATE PET/MR with multi-parametric SUV and Patlak analysis in the diagnosis and management of intracranial meningioma. Results: 19 subjects with meningioma underwent dynamic 68Ga-DOTATATE PET/MR. Time-activity curves were generated in 84 volumes of interest (53 meningioma, 9 post-treatment-change, 22 cranial blood pool reference in superior sagittal sinus, SSS). Region-specific net binding rate constant Ki was determined using the standard and generalized Patlak (sPatlak and gPatlak) methods with a population-based reference input function. Absolute and relative mean and maximum SUVs were extracted from the 50 minutes (SUV50) and the last 10 minutes (SUV10) of acquisition. Spearman correlation, Mann-Whitney, and Wilcoxon tests were performed. In meningioma, absolute and relative maximum SUV50 demonstrated a strong, significant, positive correlation with sPatlak Ki (r = 0.82, p < 0.0001 and r = 0.85, p < 0.0001, respectively). Similar results were found in post-treatment-change regions (r = 0.88, p = 0.007 and r = 0.83, p = 0.015, respectively). Mean SUV50 demonstrated similar correlations with sPatlak Ki in both subgroups. No significant differences were observed between sPatlak and gPatlak Ki correlations with SUV. All SUV and Ki metrics were significantly higher in meningioma versus post-treatment-change regions. SUV50 and SUV10 metrics for each sub-cohort were not significantly different. No lesions were reclassified based on SUV10 or Ki compared to SUV50. Conclusions: Multi-parametric SUV and Patlak Ki analysis with 68Ga-DOTATATE PET/MR is feasible and can differentiate meningioma from post-treatment-change. Ki may improve quantification of postoperative residual/ recurrent meningioma. SUV10 and SUV50 yielded comparable quantification suggesting feasibility for shorter PET scans.Trial Registration Number (ClinicalTrials.gov ID): NCT04081701, Registration Date: September 9, 2019