Negative 18F-FET PET/CT in brain metastasis recurrence: a teaching case report

Samirah Alshehri; John Prior; Mohammed Moshebah; Luis Schiappacasse; Vincent Dunet

doi:10.1186/s41824-021-00115-0

Negative ¹⁸F-FET PET/CT in brain metastasis recurrence: a teaching case report

Eur J Hybrid Imaging. 2021 Nov 22;5(1):21. doi: 10.1186/s41824-021-00115-0.

Authors

Samirah Alshehri¹, John Prior², Mohammed Moshebah³, Luis Schiappacasse⁴, Vincent Dunet³

Affiliations

¹ Service of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland. samirah.alshehri428@gmail.com.
² Service of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
³ Service of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
⁴ Service of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.

Abstract

Positron emission tomography (PET) using O-(2-[¹⁸F]fluoroethyl)-L-tyrosine (¹⁸F-FET) PET has been shown to be a useful tool for differentiating radiation therapy outcomes, such as brain metastasis recurrence or radiation necrosis. We present the case of a female patient with brain metastases from pulmonary mucinous adenocarcinoma with suspicion of tumor recurrence on follow-up magnetic resonance imaging (MRI) after radiosurgery. ¹⁸F-FET PET/computed tomography (CT) was indicative of radiation necrosis. Due to the patient's medical history and the discrepancy between the brain MRI and PET/CT results, surgical biopsies were decided, which were positive for brain metastasis recurrence. The diagnosis of metastasis recurrence may also be challenging on ¹⁸F-FET PET/CT. In case of discrepancies between MRI and PET/CT results, false-negative ¹⁸F-FET PET/CT remains a possibility and requires careful follow-up or biopsy.

Keywords: Brain; Metastasis; Necrosis; Radiation.