Use of PET Imaging in Neuro-Oncological Surgery

Abstract

This review provides an overview of current applications and perspectives of PET imaging in neuro-oncological surgery. The past and future of PET imaging in the management of patients with glioma and brain metastases are elucidated with an emphasis on amino acid tracers, such as O-(2-[¹⁸F]fluoroethyl)-L-tyrosine (¹⁸F-FET). The thematic scope includes surgical resection planning, prognostication, non-invasive prediction of molecular tumor characteristics, depiction of intratumoral heterogeneity, response assessment, differentiation between tumor progression and treatment-related changes, and emerging new tracers. Furthermore, the role of PET using specific somatostatin receptor ligands for the management of patients with meningioma is discussed. Further advances in neuro-oncological imaging can be expected from promising new techniques, such as hybrid PET/MR scanners and the implementation of artificial intelligence methods, such as radiomics.

Keywords: FET PET; PET imaging; brain metastasis; glioblastoma; glioma; meningioma; neuro-oncological surgery; neurosurgery; somatostatin receptor.

Figure 1

(upper row) A 59-year-old male patient diagnosed with an IDH-wild-type glioblastoma (WHO CNS grade 4). Following resection and chemoradiation with temozolomide, the contrast-enhanced MRI (CE-T1w MRI) suggested tumor relapse in the right parietal region 7 months after completing radiotherapy. Accordingly, the dynamic FET PET scan revealed pathologically increased FET uptake right parietal (TBR_max, 4.2) and decreased time–activity curve; (lower row). A 37-year-old female patient diagnosed with an IDH-wild-type glioblastoma (WHO CNS grade 4). Following resection and chemoradiation with temozolomide, the contrast-enhanced MRI suggested tumor relapse in the left frontal region 7 months after completing radiotherapy. In contrast to the patient in the upper row, the FET uptake in the left frontal region was not pathologically increased (TBR_max, 1.6) with a steadily increasing time–activity curve, indicating reactive treatment-related changes. SUV = standardized uptake value.

Figure 2

75-year-old female patient with a left frontotemporal transitional meningioma of the WHO grade 1. ⁶⁸Ga-DOTATATE PET/CT shows no postoperative remnants of the left frontotemporal tumor (black arrow). Pronounced tracer uptake in the right parasellar region indicates a meningioma in correlation to the MRI (white arrow). Notably, a small focal uptake posterior to the right orbital region indicates an additional meningioma. In spatial correspondence, the MRI shows equivocal findings (white arrowhead). SUV = standardized uptake value.