A correlative study of FDG PET, MRI/CT, electroencephalography, and clinical features in subacute sclerosing panencephalitis

Abstract

Objective: To describe F-18 fluorodeoxyglucose positron emission tomography (FDG PET) profile in patients with subacute sclerosing panencephalitis (SSPE) and to investigate its possible correlation with clinical, electroencephalography (EEG) or magnetic resonance imaging/computed tomography (MRI/CT) findings.

Methods: EEG recording, MRI/CT and FDG PET imaging were performed in 16 patients with SSPE (1.9-15.6 years). FDG PET scans were assessed visually and in standardized uptake values. Finally, all the findings including clinical data were compared.

Results: MRI was abnormal in 10 patients. It was normal in 6 of 10 patients in earlier clinical stages. Nonspecific T2-weighted white matter findings were the most consistent MRI finding (10 patients). No thalamic lesion was detected in MRI/CT. FDG PET imaging was abnormal in 14 patients (8/10 patients in earlier stages). Glucose metabolism was decreased in thalamus, cerebellum or cerebral cortex in 12, 12, and 9 patients, respectively. Frontal cortex metabolism was preserved in earlier clinical stages. FDG PET imaging revealed putaminal hypermetabolism in 7 patients. However, MRI indicated striatal abnormality only in 2 patients with prolonged disease and later clinical stage. Three patients with putaminal hypermetabolism experienced a more rapid clinical deterioration. Onset age of SSPE, age of measles infection and EEG findings were not correlated with the imaging findings.

Conclusions: Our findings suggest that FDG PET imaging can indicate affected brain regions in SSPE more confidently and earlier than MRI. FDG PET imaging would provide new insights into the pathogenesis of SSPE and help to develop new approaches to the patients with SSPE.