MR of lissencephaly.

MR imaging was performed on a 2-year-old girl whose history included low Apgar score, hypotonicity, and myoclonic seizures at birth . Her psychomotor and growth development were retarded. She had mild microcephaly and was hypotonic. Electroencephalography showed generalized epileptogenic activity. MR imaging was performed on a 0.5-T scanner. T1-weighted images, SE 500/30, performed in the axial , sagittal, and coronal planes (Fig. 1) showed total absence of cortical sulci, apart from primitive sylvian, calcarine, and parietal occipital fissures.