[SPECT (single photon emission computed tomography) findings in 4 cases of neuronal migration disorders]

We report SPECT findings in four children with various types of neuronal migration disorders. SPECT of a patient with heterotopia showed a protrudent abnormal shadow into the centrum semiovale, the density of which was same as that of normal gray matter. The function and the metabolism of heterotopia appear same as those of the normal gray matter. SPECT of a patient with pachygyria showed decreased blood flow in the areas of thickened cortex. This finding seems to indicate hypofunction of those lesions. SPECT of a patient with hemimegalencephaly showed an increased blood flow in the ipsilateral hemisphere and decreased blood flow in the contra-lateral hemisphere. In the literature, increased contents of neuronal elements in the affected site and arterio-venous shunt with cardiac failure have been reported in hemimegalencephaly. These pathologies may be related to our SPECT findings. SPECT of a patient with cortical dysplasia showed extensive lesions of decreased blood flow which was more wide spread than abnormal lesions detected by MRI. SPECT may be more sensitive than MRI to detect cortical dysplasias.