Neuronal Migration Disorders.

Enhanced understanding of brain development has led to increased awareness of the links between disorders of neuronal migration and seizure disorders. A significant number of patients with intractable epilepsy have cortical malformations that originated during neuronal migration. Magnetic resonance imaging plays a primary role in the diagnosis and classification of neuronal migration disorders. These disorders include polymicrogyria, schizencephaly, lissencephaly, heterotopia, and focal cortical dysplasia. Imaging protocols continue to evolve to provide critical assessment of anatomic and physiologic traits of these disorders to better treat and prevent seizures.

Severe gyration and migration disorder in fetofetal transfusion syndrome: two case reports and a review of the literature on the neurological outcome of children with lesions on neuroimaging.

INTRODUCTION: Fetofetal transfusion syndrome is a dreaded cause of morbidity and mortality in monochorionic pregnancies. CASE REPORTS: We present two pairs of twins one of which we have followed for more than 6 years. The donors suffer from cerebral palsy, orofacial, and motor problems, and both are significantly smaller than their recipient twins. Interestingly, cranial MRI revealed medial frontal lobe polymicrogyria, ventriculomegaly, and decreased thickness in both parietal lobes in both donors. We suggest this as a possible feature of fetofetal transfusion syndrome. REVIEW: A minireview of the literature on neuroimaging and neurodevelopmental outcome in fetofetal transfusion syndrome is presented. CONCLUSION: While the close resemblance of the imaging features of both cases is likely incidental further study of a connection between migration and gyration disorders and fetofetal transfusion syndrome is warranted.

Clinical, imaging, and immunohistochemical characteristics of focal cortical dysplasia Type II extratemporal epilepsies in children: analyses of an institutional case series.

OBJECTIVE Focal cortical dysplasia (FCD) Type II is divided into 2 subgroups based on the absence (IIA) or presence (IIB) of balloon cells. In particular, extratemporal FCD Type IIA and IIB is not completely understood in terms of clinical, imaging, biological, and neuropathological differences. The aim of the authors was to analyze distinctions between these 2 formal entities and address clinical, MRI, and immunohistochemical features of extratemporal epilepsies in children. METHODS Cases formerly classified as Palmini FCD Type II nontemporal epilepsies were identified through the prospectively maintained epilepsy database at the British Columbia Children's Hospital in Vancouver, Canada. Clinical data, including age of seizure onset, age at surgery, seizure type(s) and frequency, affected brain region(s), intraoperative electrocorticographic findings, and outcome defined by Engel's classification were obtained for each patient. Preoperative and postoperative MRI results were reevaluated. H & E-stained tissue sections were reevaluated by using the 2011 International League Against Epilepsy classification system and additional immunostaining for standard cellular markers (neuronal nuclei, neurofilament, glial fibrillary acidic protein, CD68). Two additional established markers of pathology in epilepsy resection, namely, CD34 and α-B crystallin, were applied. RESULTS Seven nontemporal FCD Type IIA and 7 Type B cases were included. Patients with FCD Type IIA presented with an earlier age of epilepsy onset and slightly better Engel outcome. Radiology distinguished FCD Types IIA and IIB, in that Type IIB presented more frequently with characteristic cortical alterations. Nonphosphorylated neurofilament protein staining confirmed dysplastic cells in dyslaminated areas. The white-gray matter junction was focally blurred in patients with FCD Type IIB. α-B crystallin highlighted glial cells in the white matter and subpial layer with either of the 2 FCD Type II subtypes and balloon cells in patients with FCD Type IIB. α-B crystallin positivity proved to be a valuable tool for confirming the histological diagnosis of FCD Type IIB in specimens with rare balloon cells or difficult section orientation. Distinct nonendothelial cellular CD34 staining was found exclusively in tissue from patients with MRI-positive FCD Type IIB. CONCLUSIONS Extratemporal FCD Types IIA and IIB in the pediatric age group exhibited imaging and immunohistochemical characteristics; cellular immunoreactivity to CD34 emerged as an especially potential surrogate marker for lesional FCD Type IIB, providing additional evidence that FCD Types IIA and IIB might differ in their etiology and biology. Although the sample number in this study was small, the results further support the theory that postoperative outcome-defined by Engel's classification-is multifactorial and determined by not only histology but also the extent of the initial lesion, its location in eloquent areas, intraoperative electrocorticographic findings, and achieved resection grade.

Utility of fetal MRI for workup of fetal central nervous system anomalies in an Australian maternal-fetal medicine cohort.

OBJECTIVES: To evaluate how fetal MRI is influencing current clinical practice and outcomes for central nervous system (CNS) anomalies in the Australian maternal-fetal medicine (MFM) setting. MATERIAL AND METHODS: Retrospective audit of cases January 2008-August 2013 referred for MFM ultrasound and MRI for suspected fetal CNS anomaly. Demographics, referral information, initial MFM diagnoses and investigations, MRI diagnoses, subsequent pregnancy management and perinatal outcome were examined. RESULTS: Fifty-seven women (41 singleton, 16 twin pregnancies) were seen at mean gestation of 23.7 ± 6.5 weeks. Major referral indications included ventriculomegaly (VM, 39%) and posterior fossa anomaly (PFA, 18%). MRI was performed at mean 27.2 ± 5.3 weeks. Diagnosis was altered from ultrasound in 31/57 cases (54%); 14 improving and 17 worsening prognosis. MRI findings worsening prognosis were more significant VM and PFA, agenesis of the corpus callosum, neuronal migration disorders and intraventricular haemorrhage. TOP or selective reduction occurred in 11 of 57 cases after full clinical workup (six where MRI worsened prognosis, five where MRI confirmed US poor prognosis). Mean gestation at birth was 37.2 ± 4.1 weeks for continuing pregnancies. There were nine cases of additional postnatal diagnoses, including four CNS anomalies. After neonatal workup, physical and/or developmental delay was anticipated for at least 14 of 43 (33%) infants. CONCLUSIONS: MRI added significant diagnostic information in about half the cases referred for workup of suspected CNS anomaly. In six of 17 cases where MRI worsened prognosis, TOP was chosen. Both additional CNS and non-CNS anomalies were diagnosed postnatally in 20%, emphasising the uncertain prognosis for, and evolution of, suspected CNS anomaly in fetuses.