Automatic Segmentation of the Cerebellum in Ultrasound Volumes of the Fetal Brain / Segmentación automática del cerebelo en volúmenes de ultrasonido del cerebro fetal

The size of the cerebellum in ultrasound volumes of the fetal brain has shown a high correlation with gestational age, which makes it a valuable feature to detect fetal growth restrictions. Manual annotation of the 3D surface of the cerebellum in an ultrasound volume is a time consuming task, which needs to be performed by a highly trained expert. In order to assist the experts in the evaluation of cerebellar dimensions, we developed an automatic scheme for the segmentation of the 3D surface of the cerebellum in ultrasound volumes, using a spherical harmonics model. In this work we present our validation results on 10 ultrasound volumes in which we have obtained an adequate accuracy in the segmentation of the cerebellum (mean Dice coefficient of 0.689). The method reported shows potential to effectively assist the experts in the assessment of fetal growth in ultrasound volumes.

El tamaño del cerebelo, en un volumen de ultrasonido del cerebro fetal, ha mostrado una alta correlación con la edad gestacional, lo que hace importante a esta medición para la detección de restricciones del crecimiento del feto. La anotación manual de la superficie 3D del cerebelo en un volumen de ultrasonido es una tarea demandante, que debe ser realizada por un experto. Con el propósito de apoyar a los expertos en la evaluación de las dimensiones del cerebelo fetal, hemos desarrollado un método automático para la segmentación de la superficie 3D del cerebelo en volúmenes de ultrasonido, utilizando un modelo de harmónicos esféricos (spherical harmonics). En este trabajo presentamos los resultados de una evaluación del método automático en 10 volúmenes de ultrasonido con los que hemos obtenido un valor adecuado de exactitud (coeficiente promedio de Dice de 0.689). El método reportado tiene potencial para asistir de manera efectiva a los expertos en la evaluación del crecimiento fetal, utilizando volúmenes de ultrasonido.

Social and economic factors influencing a fetal surgery program for complicated monochorionic twin pregnancies in a developing country.

OBJECTIVE: To analyze social and economic factors affecting the implementation of a fetal surgery program in a developing country. MATERIALS AND METHODS: During an 18-month period, 30 women with complicated monochorionic diamniotic twin pregnancies were evaluated. 27 women had twin-to-twin transfusion syndrome (TTTS), 2 women had a selective intrauterine growth restriction, and 1 a discordant twin pregnancy with 1 fetus with a severe open neural tube defect. The TTTS cases were treated with fetoscopic laser ablation of the interplacental vascular communications and the remaining 3 cases with bipolar cord occlusion of the affected twin. The patients were evaluated using family income levels (very low, low, median, and high income). Demographic characteristics, gestational age at referral, the prevalence of infections, tocolysis care with hospital readmission, prolonged hospital stay until delivery, and gestational age at delivery were evaluated. RESULTS: The overall survival rate of fetuses treated with laser ablation was 60% (32/54). Survival of at least 1 twin was achieved in 21/27 pregnancies (77%), and survival of both twins in 12/27 pregnancies (44%). The 3 pregnancies treated with cord occlusion had survival of the normal twin. Patients with low and very low family income showed a significantly higher prevalence of vaginal infections, increased periods of tocolysis requiring hospitalization, prolonged hospital stay until the end of pregnancy, and lower gestational age at delivery. CONCLUSION: When a fetal surgery program is implemented in a developing country, social and economic factors will influence the overall healthcare costs and treatment outcomes.

[Usefulness of ultrasonographic markers in chromosomal abnormalities]. / Utilidad de los marcadores ultrasonográficos de cromosomopatía.

During a 3 and 1/2 years, 132 pregnancies were diagnosed as having a wide variety of congenital abnormalities. A high resolution ultrasound and multidisciplinary approach was used. In 95 cases fetal karyotyping was made. In this group the incidence of chromosomal abnormalities diagnosed during the period and phenotypic expression of the different types of chromosomal abnormalities was investigated. 29 abnormal karyotypes were found; 11 trisomy 18, 7 in monosomy X, 4 in trisomy 21, 3 in trisomy 13, 1 with tetraploidy (92XXYY), 1 Turner mosaic (45XO 68% 46XY 32%), 2 inversions of choromosome 9. Of the total abnormal chromosomal diagnosed during the period (N = 57), this group represented 49.2%, compared to 5 to 15% found in other risk groups. 224 congenital abnormalities were found. 43 (19%) isolated, and 181 (81%) associated. Of the 224 congenital abnormalities diagnosed, 80 (36%) were associated with chromosomal abnormalities. The most associated markers were duodenal atresia, heart defect, microcephaly, enlarged posterior fossa, and cystic hygromata. A specific markers pattern was found for each aneuploidy; heart defects for trisomy 18, holoprosencephaly and faciel cleft for trisomy 13, and cystic hygromata for monosomy X. It was concluded that the ultasound can be the most useful method to select the group of pregnant women with a higher risk of abnormal karyotype.