神経芽細胞遊走障害のsingle photon emission computed tomography（SPECT）所見

SPECT (Single Photon Emission Computed Tomography) Findings in 4 Cases of Neuronal Migration Disorders

　神経芽細胞遊走障害の4例にsingle photon emission computed tomography（SPECT）を行った。異所性灰白質は正常灰白質と同じ血流量を示し，脳回肥厚症では灰白質肥厚部位は低血流として示された。これまでのPET所見，病理所見の報告と考え合わせると，異所性灰白質は機能的には正常灰白質と同程度であり，脳回肥厚部は低下していると考えられた。片側巨大脳症では相対的に肥大部位の血流増加，対側の血流低下がみられた。患側で神経細胞核の増加していること，動静脈シャントがみられることが言われており，これらと関連した所見と考えられた。脳形成障害ではMRIで予想される部位よりも広範に脳血流低下部位が示され，SPECTがより鋭敏に病変を表すものと考えられた。

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 den-sity 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 find-ings. 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.