Dynamic [18F]2-FDG-PET-imaging in patients with GLUT1-deficiency syndrome before and on a ketogenic diet

Introduction: GLUT1-deficiency syndrome results from impaired glucose transport across the blood-brain barrier. The diagnosis is based on hypoglycorrhachia, impaired in vitro glucose uptake into erythrocytes, and molecular analyses. We investigated the potential of dynamic PET imaging to show the transport defect in vivo and the impact of ketosis in the patient.

Methods: Two female patients with GLUT1-deficiency syndrome (5 and 11 y/o) were investigated before and a few months after the introduction of a ketogenic diet. Following an i.v. injection of [¹⁸F]FDG a dynamic PET-acquisition for 60min was performed with arterialised venous blood samples. Glucose transport and metabolism were calculated applying a 3-compartment model.

Results: In both patients a cortical transport limitation was detected. In the presence of ketosis as an alternative fuel the transport limitation was less prominent in the elder patient and unchanged in the younger patient.

Conclusion: GLUT1-deficiency syndrome can be identified in vivo by dynamic [¹⁸F]FDG-PET imaging. This method can potentially contribute to the assessment of the therapeutic effect of a ketogenic diet in this disorder.

Keywords: GLUT1-deficiency syndrome, PET, [¹⁸F]FDG, ketogenic diet, blood-brain barrier