AUTHOR=Roytman Michelle , Kim Sean , Glynn Shannon , Thomas Charlene , Lin Eaton , Feltus Whitney , Magge Rajiv S. , Liechty Benjamin , Schwartz Theodore H. , Ramakrishna Rohan , Karakatsanis Nicolas A. , Pannullo Susan C. , Osborne Joseph R. , Knisely Jonathan P. S. , Ivanidze Jana 

TITLE=PET/MR Imaging of Somatostatin Receptor Expression and Tumor Vascularity in Meningioma: Implications for Pathophysiology and Tumor Outcomes

JOURNAL=Frontiers in Oncology

VOLUME=Volume 11 - 2021

YEAR=2022

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2021.820287

DOI=10.3389/fonc.2021.820287

ISSN=2234-943X

ABSTRACT=Background and Purpose: Meningiomas, the most common primary intracranial tumor, are vascular neoplasms which express somatostatin receptor-2 (SSTR2). The purpose of this investigation was to evaluate if a relationship exists between tumor vascularity and SSTR2 expression, which may play a role in meningioma prognostication and clinical management. 
Materials and Methods: Gallium-68-DOTATATE PET/MRI with DCE-perfusion was prospectively performed. Clinical and demographic patient characteristics were recorded. Tumor volumes were segmented and superimposed onto parametric DCE-maps including flux rate constant (Kep), transfer constant (Ktrans), extravascular volume fraction (Ve) and plasma volume fraction (Vp). Meningioma PET SUV and SUV ratio to superior sagittal sinus (SUVRSSS), were recorded. Pearson correlation analyses were performed. In a random subset, analysis was repeated by a second investigator and intraclass correlation coefficients (ICC) were determined. 
Results: 36 patients with 60 meningiomas (20 WHO-1, 27 WHO-2, 13 WHO-3) were included. Mean Kep demonstrated a strong significant positive correlation with SUV (r = 0.84, p < 0.0001) and SUVRSSS (r = 0.81, p < 0.0001). When stratifying by WHO Grade, this correlation persisted in WHO-2 (r = 0.91, p < 0.0001) and WHO-3 (r = 0.92, p = 0.0029), but not WHO-1 (r = 0.26, p = 0.4, SUVRSSS). ICC was excellent (0.97-0.99). 
Conclusion: DOTATATE PET/MRI demonstrated a strong significant correlation between tumor vascularity and SSTR2 expression in WHO-2 and -3, but not WHO-1 meningiomas, suggesting biological differences in the relationship between tumor vascularity and SSTR2 expression in higher-grade meningiomas, the predictive value of which will be tested in future work.