DUAL PET IMAGING OF NEOPLASTIC AND INflAMMATORY BIOMARKERS IN HIGH GRADE GLIOMA

Abstract AIMS To characterize spatial distributions of 18kDa translocator protein (TSPO) and amino acid uptake as measured through dynamic [11C] (R)-PK11195 [11C]-methionine PET in high-grade glioma. METHOD Twelve patients with newly diagnosed glioma underwent dual studies. binding potential (BPND) maps were generated using simplified reference tissue model grey-matter cerebellar time- activity-curve input-function. was calculated tumour-to-background ratio (TBR). Volumes interest (VOIs) defined on T1W post-contrast MRI contrast-enhancing (CE) tumour a ‘peritumoural’ region 5mm from the CE edge. Voxel-wise comparison tracers used Pearson’s correlation coeffcient. VOIs furthermore subdivided into higher/lower TSPO (BPND > 0.17) methionine (TBR 1.7). RESULTS Within CE, voxel-wise showed strong (r 0.7) eight subjects, moderate 0.5) three subjects weak < one subject. Volume (mm3) high BPND/high TBR accounted for 62±29% whereas BPND/low 13±16%. peritumoral area, there small reduction proportion group (6/12) but pro- portion voxels higher lower substantially greater (35±16%). CONCLUSIONS glioma, is overall between expression uptake. However, peritumoural are areas elevated without increased which could represent an inflammatory component or discrete neoplastic cell population that may not be adequately standard imaging biomarkers.