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

Abstract

Background and PurposeMeningiomas, the most common primary intracranial tumor, are vascular neoplasms that 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 MethodsGallium-68-DOTATATE PET/MRI with dynamic contrast-enhanced (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 standardized uptake value (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 (ICCs) were determined.ResultsThirty-six patients with 60 meningiomas (20 WHO-1, 27 WHO-2, and 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).ConclusionDOTATATE PET/MRI demonstrated a strong significant correlation between tumor vascularity and SSTR2 expression in WHO-2 and WHO-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.

Parahydrogen-induced polarization allows 2000-fold signal enhancement in biologically active derivatives of the peptide-based drug octreotide

“…As the hyperpolarization by PHIP is time-limited to experiments on the order of seconds due to relaxation, possible application areas are, e.g., studies of fate and distribution of bioactive compounds as well as their metabolites in cell cultures or binding kinetics between octreotide and proteins. In certain cases, such as meningiomas, octreotide PET has been replaced by special MRI techniques, utilizing untargeted gadolinium-based contrast agents 46 . Octreotide in nanoparticles with gadolinium complexes has been successfully investigated as a possible targeted contrast agent for MRI 47 , 48 .…”

Dynamic Contrast Enhanced-MRI and Apparent Diffusion Coefficient Quantitation for Differentiate Hepatocellular Carcinoma from Hepatocellular Adenoma

“…K trans (transfer constant), K ep (rate constant), and V e (extravascular extracellular volume fraction) are three of the derived parameters that show promise as quantitative metrics for revealing tumor vascularization, perfusion, and permeability. Recent studies have focused on these variables because they provide insightful data beyond traditional morphological assessments [ 7 ].…”