Avaliação do comprimento e área do corpo caloso fetal por meio da ultrassonografia tridimensional / Assessment of length and area of corpus callosum by three-dimensional ultrasonography

OBJETIVO: determinar os valores de referência para o comprimento e a área do corpo caloso fetal entre a 20ª e 33ª semanas de gestação por meio da ultrassonografia tridimensional (US3D). MÉTODOS: foi realizado um estudo do tipo corte transversal com 70 gestantes normais entre a 20ª e 33ª semanas de gestação. Utilizou-se um aparelho da marca Accuvix XQ, equipado com transdutor convexo volumétrico (3 a 5 MHz). Para a obtenção do corpo caloso fetal, foi utilizado um plano transfrontal, com a sutura metópica como janela acústica. Para o cálculo do comprimento, utilizou-se a distância entre os pontos médios dos polos proximal e distal do corpo caloso. Para o cálculo da área, a delimitação manual da superfície externa do corpo caloso foi realizada. Para o comprimento e a área do corpo caloso, foram calculadas: as médias, as medianas, os desvios padrão e os valores máximo e mínimo. Para a correlação da área e do comprimento do corpo caloso com a idade gestacional e o diâmetro biparietal foram criados diagramas de dispersão, sendo a qualidade dos ajustes verificada pelo coeficiente de determinação (R²). Para a variabilidade intraobservador, utilizou-se o coeficiente de correlação intraclasse (CCI). RESULTADOS: a média do comprimento do corpo caloso variou de 21,7 mm (18,6 - 25,2 mm) a 38,7 mm (32,6 - 43,3 mm) entre a 20ªe 33ª semanas, respectivamente. A média da área do corpo caloso variou de 55,2 mm² (41,0 - 80,0 mm²) a 142,2 mm² (114,0 - 160,0 mm²) entre a 20ªe 33ª semanas, respectivamente. O comprimento e a área do corpo caloso foram fortemente correlacionados com a idade gestacional (R² = 0,7 e 0,7, respectivamente) e com o diâmetro biparietal (R² = 0,7 e 0,6, respectivamente). A variabilidade intraobservador foi adequada com CCI = 0,9 e 0,9 para o comprimento e área, respectivamente. CONCLUSÕES: valores de referência para o comprimento e área do corpo caloso fetal entre a 20ªe 33ª semanas foram determinados. A variabilidade intraobservador foi adequada.

PURPOSE: to establish reference values for the length and area of the fetal corpus callosum between the 20th and 33rd weeks of gestation using three-dimensional ultrasound (3DUS). METHODS: this cross-sectional study involved 70 normal pregnancies with gestational age between 20 and 33 weeks. An Accuvix XQ instrument with a convex volumetric transducer (3 to 5 MHz) was used. To assess the corpus callosum, a transfrontal plane was obtained using the metopic suture as an acoustic window. Length was obtained by measuring the distance between the proximal and distal extremities of the corpus callosum. Area was obtained by manual tracing of the external corpus callosum surface. The means, medians, standard deviations, and maximum and minimum values were calculated for the corpus callosum length and area. Scatter graphs were created to analyze the correlation between corpus callosum length and area and gestational age and biparietal diameter, the quality adjustments was verified according to the determination coefficient (R²). The intraclass correlation coefficient (ICC) was used to assess the intraobserver variability. RESULTS: mean corpus callosum length increased from 21.7 (18.6 - 25.2 mm) to 38.7 mm (32.6 - 43.3 mm) between 20 and 33 weeks of pregnancy, respectively. Mean corpus callosum area increased from 55.2 (41.0 - 80.0 mm²) to 142.2 mm² (114.0 - 160.0 mm²), between 20 to 33 weeks of pregnancy, respectively. There was a strong correlation between corpus callosum length and area and gestational age (R² = 0.7 and 0.7, respectively) and biparietal diameter (R² = 0.7 and 0.6, respectively). Intraobserver variability was appropriate, with an ICC of 0.9 and 0.9 for length and area, respectively. CONCLUSIONS: reference values for corpus callosum length and area were established for fetuses between 20 and 33 weeks gestation. Intraobserver variability was appropriate.

Disgenesia do corpo caloso e lipoma: considerações embriológicas básicas e aspectos de imagem à ressonância magnética / Corpus callosum dysgenesis and lipoma; embriologic and magnetic resonance imaging aspects

O corpo caloso é a maior via de fibras de associação que comunicam os dois hemisférios cerebrais. O aprimoramento no estudo das suas malformações foi alcançado após o advento da ressonância magnética, que permite estudar detalhadamente as suas várias porções, além de possibilitar a identificação de outras anormalidades encefálicas associadas. O lipoma do corpo caloso é uma dessas alterações e representa achado freqüente no espectro das disgenesias do corpo caloso. Os objetivos dos autores são os de recordar o mecanismo embriológico envolvido nas disgenesias do corpo caloso e na formação dos lipomas desta região e revisar os achados à ressonância magnética nestas situações.

Disgenesia do corpo caloso e más-formações associadas: achados de tomografia computadorizada e ressonância magnética / Dysgenesis of the corpus callosum and associated malformations: computed tomography and magnetic resonance imaging findings

O termo disgenesia do corpo caloso refere-se a uma má-formação deste com origem na embriogênese do telencéfalo. O relato analisa os achados de tomografia computadorizada e ressonância magnética em 11 pacientes com disgenesia calosa e em um caso de corpo caloso normal com lipoma associado. Esta pode ser distinguida em três grupos: agenesia total (três casos), agenesia parcial (seis casos) e hipoplasia (dois casos). Anomalias associadas foram observadas em nove casos, incluindo má-formação de Chiari tipo II (um caso), esquizencefalia (um caso), cisto inter-hemisférico (dois casos), heterotopia nodular (um caso), cisto de Dandy-Walker (um caso) e lipoma do corpo caloso (quatro casos). Este artigo demonstra um espectro destes distúrbios, auxiliando na sua interpretação diagnóstica.

Callosal dysgenesis is a malformation of the corpus callosum with origins in the embryogenesis of the telencephalon. We reviewed the computed tomography and magnetic resonance imaging findings of 11 patients with callosal dysgenesis and one patient with normal corpus callosum associated with a lipoma. The patients were divided into three distinct groups: total agenesis (three patients), partial agenesis (six patients) and hypoplasia (two patients). Associated abnormalities were observed in nine patients, including Chiari II malformation (one patient), schizencephaly (one patient), interhemispheric cyst (two patients), Dandy-Walker cyst (one patient), nodular heterotopy (one patient) and lipoma of the corpus callosum (four patients). This paper presents a review that may contribute to the diagnosis of these disorders

Sexual dimorphism in interhemispheric relations: anatomical-behavioral convergencea

An embryogenetic hypothesis states that hemispheric specialization is inversely related to callosal connectivity (Geschwind and Galaburda, 1985). We tested this hypothesis (i) anatomically by relating postmortem planum temporale asymmetry to regional callosal morphology and (ii) behaviorally by relating the right visual field advantage in a lateralized lexical decision task with associative primes to regional callosal morphometry using magnetic resonance imaging (MRI). The postmortem study showed a significant negative correlation between planum temporale asymmetry and the number of small diameter fibers in the isthmus of the corpus callosum, but only for males. The MRI study showed a significant negative correlation between the right visual hemifield advantage for associated words and the cross section size of the isthmus of the corpus callosum, but again only in males. There was no sex difference in either the anatomical asymmetry, the behavioral asymmetry, or the callosal morphology. These convergent results suggest that there is a sexual dimorphism in interhemispheric relations in humans

Development of interhemispheric connections through the anterior commissure in hamsters

The development of interhemispheric connections through the anterior commissure was studied in hamsters by use of the postmortem fluorescent tracer diI. Labelled commissural axons were seen to aaproach midline and cross it on E14 (E1, day of conception), extend into the opposite hemisphere and rech the terminal targets on E15, and start to arborize on E16. OnP1(day of birth), a few labelled neurons could already be seen in the anterior olfactory nucleous, olfactoru tubercle, piriform and insular cortices, nucleus of the lateral olfactory tract, bed nucleous of the stria terminalis, amygdaloid complex, temporal, perihinal and entorhinal cortices. In all these regions, labelled neurons became progressively more numerous on P3, P5 and P10, but their distribution did not change. Since no evidence of topographical exuberance of connections could be found, it is hypothesized that the development of anterior commissure connections is entirely progressive, lacking the regressive events that characterize callosal ontogenesis

The development of callosal and corticocorcal innervation in the neocortex of the hamster

The development of cortical afferentation by callosal and ipsilateral corticocortical fibers was studied in hamsters by transport of wheat germ agglutinin conjugated to horseradish peroxidase. Elongation of callosal axons (and possibly also of corticocortical fibers) started a couple of days before birth and extended through the first postnatal days. After a "waiting" period of a few days, axons were seen innervating restricted target sectors of the cortex. The zones of origin of these projections were initially exuberant, but they were subsequently trimmed down to overlap with the corresponding terminal fields