[P2-68] FDG-PET findings in glucose transporter 1 deficiency: activity ratio of lenticular nuclei and thalami
[Rationale] Glucose transporter 1 deficiency syndrome (GLUT1-DS) is caused by impaired glucose uptake at the blood–brain barrier. Although neuroimaging findings are considered nonspecific, it was reported that FDG-PET shows low uptake in thalami and cerebral cortex and relatively high uptake in basal ganglia. We performed FDG-PET study to reveal if the FDG-PET is helpful in the diagnosis of GLUT1-DS. [Methods] We performed FDG-PET in 7 patients (age: 3 to 21 years) with GLUT1-DS. PET was compared with those of 45 controls by statistical parametric mapping (SPM8). The controls had epilepsy of unknown etiology and normal MRI. We also measured ratio of mean radioactivity in lenticular nuclei and thalami in each patient and control by using regions of interest. We determined sensitivity and specificity of the ratio for the diagnosis of GLUT1-DS. [Results] SPM showed significant decrease in bilateral thalami and increase in bilateral basal ganglia in patients with GLUT1-DS. The mean value of the lenticular nuclei/thalami ratio was 1.66 ± 0.17 in patients and 1.26 ± 0.09 in controls. By setting cut-off value of the lenticular nucleus/thalami ratio to 1.4, patients with Glut1-DS were differentiated from controls with sensitivity 1.00 and specificity 0.96. [Conclusion] It is useful to evaluate the lenticular nuclei/thalami ratio on FDG-PET for the diagnosis of GLUT1-DS in patients with epilepsy and unknown etiology. The unique pattern of glucose metabolism may be caused by expression of glucose transporters and local glucose metabolism in human brain from fetal period, or effect of epileptic activity on thalamo-cortical networks.