The occurrence and prognostic significance of focal defects in cerebral cortical glucose metabolism were evaluated in infants with newly diagnosed symptomatic and cryptogenic infantile spasms examined at Turku and Helsinki Universities, Finland. MRI, video-EEG, and PET were obtained within 2 weeks of diagnosis in 10 patients with symptomatic and 7 with cryptogenic infantile spasms. Twelve patients had repeat PET at 1 year of age. Cortical hypometabolic foci occurred in 13 (77%) infants; 7 had symptomatic and 6 cryptogenic spasms. In 7 of 9 reexamined with PET at age 1, foci had disappeared, and none of 6 with occipital foci had persistent hypometabolism. The focal PET abnormalities correlated with focal findings on video-EEG. Quantitative cortical and subcortical glucose metabolic rates were similar in cryptogenic and symptomatic spasms at onset. Striatal values are higher than cortical values in all patients. Focal lesions in glucose metabolism associated with infantile spasms have no prognostic value for seizure outcome. [1]

COMMENT. Cortical hypometabolic lesions demonstrated by PET in children with infantile spasms are usually transient, especially those in occipital regions, the most common localization. They are equally common in cryptogenic and symptomatic spasms. PET and video-EEG abnormalities are correlated, but PET is the better test to detect focal cortical dysfunction. PET is of no value in prognosis, whereas infants with MRI structural abnormalities are at increased risk of continuing seizures and poor developmental outcome. Most children with infantile spasms and favorable outcome have transient foci of cortical hypometabolism at onset, especially occipital in location.

Bitemporal glucose hypometabolism may be indicative of a poor prognosis, delayed development, severe dysphasia, and autism in children with infantile spasms examined by PET. (Chugani HT et al. 1996; see Progress in Pediatric Neurology III, PNB Publ, 1997;pp40-41).