Nucl Med Mol Imaging.  2022 Oct;56(5):245-251. 10.1007/s13139-022-00758-2.

Imaging Findings of  ¹⁸F‑Choline and  ¹⁸F‑DOPA PET/MRI in a Case of Glioblastoma Multiforme Pseudoprogression: Correlation with Clinical Outcome

• Filippi L
• Spanu A
• Bagni O
• Schillaci O
• Palumbo B

• KMID: 2534412
• DOI: http://doi.org/10.1007/s13139-022-00758-2

Abstract

We describe the case of 74-year-old-male, previously treated with fronto-parietal craniotomy due to primary glioblastoma multiforme (GBM), followed by concurrent radiation therapy (RT) and temozolomide (TMZ) chemotherapy. Magnetic resonance imaging (MRI) of the brain, at 1 month after completing RT + TMZ, depicted partial response. Three months later, the patient was submitted to a further brain MRI, that resulted doubtful for therapy induced changes (i.e., pseudoprogression). The patient, who had been previously treated with prostatectomy for prostate cancer (PC), underwent a positron emission tomography/computed tomography (PET/CT) scan with ¹⁸F-choline for PC biochemical recurrence. ¹⁸F-choline whole body PET/CT resulted negative for PC relapse, while segmental brain PET, co-registered with MRI, demonstrated increased tracer uptake corresponding to tumor boundaries. In order to solve differential diagnosis between pseudoprogression and GBM recurrence, brain PET/CT with ¹⁸F-L-dihydroxy-phenil-alanine ( ¹⁸F-DOPA) was subsequently performed: fused axial PET/MRI images showed increased ¹⁸F-DOPA incorporation in the peri-tumoral edema, but not in tumor boundaries, consistent with the suspicion of GBM pseudoprogression, as then confirmed by clinical and radiological follow-up.

Keyword

PET/CT ; Radiolabeled amino acids; Choline; Gliomas; Brain tumors; Precision medicine; Neurooncology