Objective: To evaluate the occurrence and prognostic importance of focal defects in cerebral cortical glucose metabolism in infants with newly diagnosed symptomatic and cryptogenic infantile spasms.
Patients and methods: Ten children with symptomatic and seven with cryptogenic infantile spasms underwent MRI, video-EEG, and PET using fluorodeoxyglucose as a tracer within 2 weeks of diagnosis. PET was repeated at 1 year of age in 12 patients.
Results: Cortical hypometabolic foci were found in 13 children (77%) with newly diagnosed spasms (six cryptogenic and seven symptomatic). The hypometabolic foci disappeared in seven of nine reexamined at age 1. The occipital foci disappeared in all (n = 6). Focal findings on PET correlated well with focal findings on video-EEG. There was no difference in quantitative cortical or subcortical glucose metabolic rate at the onset of infantile spasms between children with cryptogenic and symptomatic etiology of spasms. The glucose metabolic rate at the onset of spasms or focal lesions in glucose metabolism did not have prognostic value for seizure outcome.
Conclusions: Infantile spasms are often associated with transient cortical, especially occipital, hypometabolic foci that are not necessarily associated with structural lesions and do not indicate a poor prognosis.