RT Journal Article SR Electronic T1 Unilateral megalencephaly: correlation of MR imaging and pathologic characteristics. JF American Journal of Neuroradiology JO Am. J. Neuroradiol. FD American Society of Neuroradiology SP 523 OP 531 VO 11 IS 3 A1 Barkovich, A J A1 Chuang, S H YR 1990 UL http://www.ajnr.org/content/11/3/523.abstract AB Unilateral megalencephaly is a rare and poorly understood malformation resulting in the enlargement of all or part of a cerebral hemisphere. The clinical and radiologic features of 12 patients with unilateral megalencephaly are presented; pathologic correlation was available in four. All patients had seizures and developmental delay. Two were in congestive heart failure as a result of arteriovenous shunting through the abnormal hemisphere. The affected hemispheres showed a wide spectrum of involvement. Anomalies of neuronal migration were present, and there was a roughly inverse correlation between the severity of hemispheric involvement and the magnitude of enlargement. This correlation is explained via a proposed mechanism of a mild hemispheric insult in the middle-to-late second trimester. One patient had an extremely anomalous hemisphere that did not have characteristics of a neuronal migration anomaly and may have been a hamartomatous malformation. Our correlation of the clinical, radiologic, and pathologic features of unilateral megalencephaly, together with a theory of pathogenesis, should help elucidate this rare malformation.