Brain Death Confirmation by 18F-FDG PET/CT: A Case Series

Brain death is a state of irreversible loss of brain function in the cortex and brainstem. Diagnosis of brain death is established by clinical assessments of cranial nerves and apnea tests. Different conditions can mimic brain death. In addition, confirmatory tests may be falsely positive in some cases. In this study, we aimed to evaluate the role of positron emission tomography-computed tomography scan with 2-deoxy-2[18F]fluoro-D-glucose (18F-FDG-PET/CT) as an ancillary test in diagnosing brain death.

We analyzed 6 potential brain death donors for the confirmatory diagnosis of brain death using FDG-PET/CT. All 6 donors were brain dead by clinical criteria. All patients had electroencephalogram and brain computed tomography. Other than FDG-PET/CT, transcranial Doppler was performed in 1 patient, with other patients having no confirmatory ancillary imaging tests. Patients had nothing by mouth for 6 hours before imaging. Patients were supine in a semi-dark, noiseless, and odorless room with closed eyes. After 60 minutes of uptake,the brain PET/CT scan was performed with sequential time-of-flight-PET/CT (Discovery 690 PET/CT with 64 slices, GE Healthcare). The PET scan consisted of LYSO (Lu1.8Y0.2 SiO5) crystals with dimensions of 4.2 × 6.3 × 25 mm3. Three-dimension images were with scan duration of 10 minutes.

The PET scan confirmed brain death in 5 of the 6 cases. However, we ruled out brain death using PET/CT in a 3-year-old child, although all clinical tests confirmed brain death.

A PET scan illustrates a hollow skull phenomenon suggestive of brain death. It can be a powerful diagnostic tool to assess brain death.