Abstract：Objective: We analyzed the imaging manifestations of hemimegalencephaly(HME) in children and fetuses, in order to improve the understanding of HME, especially in fetuses, and to reduce birth defects. Methods: Eleven cases of HME confirmed by clinical and MRI from September 2011 to December 2018 were retrospectively reviewed, including 3 fetuses and 8 postnatal cases. Of the 11 patients, 8 patients underwent MRI scan only, 2 cases underwent CT and MRI examination, and 1 underwent CT examination only. Surgical treatment was performed in 2 cases. Results: The HME of 8 postnatal cases were 4 involved in the left hemisphere and 4 in the right hemisphere; all the cases had thicken cortex on the affected side, wider or irregular gyrus, pachygyria or polymicrogyria like gyrus pattern and widened and morphologically abnormal ventricles of the affected side. The midline structure shifted and crooked, and abnormal enlargement of deep gray matter nuclei in 7 cases, white matter showed T2WI hypointensity in 6 cases, gliosis in 3 cases, calcification in 1 case, heterotopic subependymal gray matter in 1 case, involvement of ipsilateral cerebellar hemisphere in 1 case, and the thick of soft tissue in the ipsilateral head and face increased. Besides, there was one case with Chiari type I. Fetal HME, prenatal ultrasound showed unilateral ventricular enlargement, and prenatal MRI all gave definite diagnosis. In all 3 cases, the biparietal diameter was larger than the normal one in the gestational week. Increased cranial cavity, cortical thickness, irregular ventricular enlargement, discrepancy between sulcus gyrus development and gestational week, and low signal intensity of T2 and T2-like sequence were found. Two cases were associated with obvious pachygyria and polymicrogyria like gyrus pattern. Conclusion: The MRI manifestations of HME are characterized by diffuse enlargement of the hemisphere, enlargement of the lateral ventricle, thickening of the cerebral cortex, loss of normal grey and white matter signals, and hamartoma-like changes. The MRI manifestations in fetal HME is similar to that of children. In addition, it is often accompanied by biparietal diameter greater than the nomal one gestational weeks, and sulcus development inconsistent with that in gestational weeks. These can be well assisted by ultrasonography to make a definite diagnosis and reduce birth defects.
葛 文，宋修峰，泮思林. 8例儿童及3例胎儿半侧巨脑畸形的影像学表现并文献复习[J]. 中国临床医学影像杂志, 2020, 31(5): 363-367.
GE Wen, SONG Xiu-feng, PAN Si-lin. Imaging manifestations of hemimegalencephaly in children and fetuses and literature review. JOURNAL OF CHINA MEDICAL IMAGING, 2020, 31(5): 363-367.
[1]Jagruti PS, Surekha BR, Meher Ursekar. Spectrum of Congenital CNS Malformations in Pediatric Epilepsy[J]. Indian Pediatr, 2004, 41(8): 831-838.
[2]Sims J. On Hypertrophy and Atrophy of the Brain[J]. Medico-Chirurgical Transactions, 1835, 19(1): 315-380.
[3]Ravikanth B, Chandrasekharan K, Ramachandran S, et al. Longitudinal CT and MR appearances of hemimegalencephaly in a patient with tuberous sclerosis[J]. Child's Nervous System, 2008, 24(3): 397-401.
[4]Chong ZZ, Shang YC, Wang S, et al. Shedding new light on neurodegenerative diseases through the mammalian target of rapamycin(Review)[J]. Prog Neurobiol, 2012, 99(2): 128-148.
[5]Palmini A, Najm I, Avanzini G, et al. Terminology and classification of the cortical dysplasias[J]. Neurology, 2004, 62(6 Suppl 3): S2-S8.
[6]Noriko S, Marissa A, Dennis J. et al. Contralateral hemimicrencephaly and clinical-pathological correlations in children with hemimegalencephaly[J]. Brain, 2006, 129(2): 352-365.
[7]Sener RN. MR demonstration of cerebral hemimegalencephaly associated with cerebellar involvement(total hemimegalencephaly)[J]. Comput Med Imaging Graph, 1997, 21(3): 201-204.
[8]Flores SL. Hemimegalencephaly: part 1. Genetic, clinical, and imaging aspects[J]. J Child Neurology, 2002, 17(5): 373-384.
[9]Broumandi David D, Hayward Ulrike M, Benzian James M, et al. Best cases from the AFIP: hemimegalencephaly[J]. RadioGraphics, 2004, 24(3): 843-848.
[10]Sato N, Ota M, Yagishita A, et al. Aberrant midsagittal fiber tracts in patients with hemimegalencephaly [J]. Am J Neuroradiol, 2008, 29(4): 823-827.
2020, Vol. 31 
