Simplified gyral pattern in severe developmental microcephalies? New insights from allometric modeling for spatial and spectral analysis of gyrification.

The strong positive-allometric relationship between brain size, cortical extension and gyrification complexity, recently highlighted in the general population, could be modified by brain developmental disorders. Indeed, in case of brain growth insufficiency, the pathophysiological relevance of the "simplified gyral pattern" phenotype is strongly disputed since almost no genotype-phenotype correlations have been found in primary microcephalies. Using surface scaling analysis and newly-developed spectral analysis of gyrification (Spangy), we tested whether the gyral simplification in groups of severe microcephalies related to ASPM, PQBP1 or fetal-alcohol-syndrome could be fully explained by brain size reduction according to the allometric scaling law established in typically-developing control groups, or whether an additional disease effect was to be suspected. We found the surface area reductions to be fully explained by scaling effect, leading to predictable folding intensities measured by gyrification indices. As for folding pattern assessed by spectral analysis, scaling effect also accounted for the majority of the variations, but an additional negative or positive disease effect was found in the case of ASPM and PQBP1-linked microcephalies, respectively. Our results point out the necessity of taking allometric scaling into account when studying the gyrification variability in pathological conditions. They also show that the quantitative analysis of gyrification complexity through spectral analysis can enable distinguishing between even (predictable, non-specific) and uneven (unpredictable, maybe disease-specific) gyral simplifications.

[Five-year outcome of mother-to-child transmission of chikungunya virus]. / Devenir a 5 ans des infections materno-foetales a virus chikungunya.

Chikungunya virus is an arbovirus (alphavirus) transmitted by Aedes albopictus in Reunion Island. A huge chikungunya outbreak swept Reunion Island in 2005- 2006. We report the first case of chikungunya neonatal infection and the 5-years outcome of the 18 neonates hospitalized in neonatal intensive care unit between June 2005 and March 2006.

[Familial cerebral cavernomas: discovery made during an epileptic seizure in a 10-year-old girl]. / Cavernome cérébral familial: révélation par une épilepsie chez une fille de 10 ans.

The assessment of an epileptic seizure in a 10-year-old girl originating from Reunion Island revealed a case of familial cerebral cavernous angioma. Multiple hemorrhagic lesions seen during a cerebral magnetic resonance imaging (MRI) scan was suggestive of cavernomas. A cerebral MRI scan in the father showed multiple asymptomatic lesions, thus confirming the familial nature. A genetic study carried out on the patient and her father confirmed the presence of a mutation of the KRIT1 gene with an autosomal dominant transmission. In these disorders, an MRI scan in the patient's parents offers great diagnostic advantages. This screening leads to precautionary measures that are easy to put in place.

[Isolated infarct of the corpus callosum: a misleading appearance]. / Infarctus isolé du corps calleux: un aspect trompeur.

We report here the case of an isolated corpus callosum infarct in a 48-year-old woman. Characteristics of this unusual condition are illustrated by multiple imaging modalities on follow-up. We discuss the pathophysiology of this rare entity and the more important differential diagnoses.

[Chronic subdural hematoma in utero. Case report with literature review]. / Hématome sous-dural chronique in utero. A propos d'un cas, revue de la littérature.

We present a case of chronic subdural hematoma diagnosed in utero by ultrasonography, and MRI at 31 weeks gestation. No cause of usual intracranial hemorrhage was found. There was no trauma. The child was operated after induced vaginal delivery at 37 weeks gestation, with good results and normal neuropsychological development after one year. We discuss the symptomatology and the therapeutic attitude in such cases.

MR diagnosis of subdiaphragmatic anomalous pulmonary venous drainage in a newborn.

Our report describes a case of infradiaphragmatic total anomalous pulmonary venous return diagnosed by MR in a newborn with an interruption of the aortic arch with ventricular septum defect and anomalous pulmonary venous drainage. The severity of the congenital cardiopathy did not permit surgical treatment and the infant died soon after. Pathology confirmed the MR findings. Magnetic resonance not only complements echocardiography but also can be used for patients in intensive care and can in our case avoid angiography.