Objectives
The purposes of this study were to describe a 3‐dimensional sonographic technique for evaluation of the fetal vermis and to compare vermian biometric parameters in fetuses with a normal and an abnormal posterior fossa.
Methods
A prospective study was conducted from 2006 through 2008 on 12 fetuses with an abnormal posterior fossa and 73 healthy control fetuses from 18 to 35 weeks' gestation. Three‐dimensional scans of the fetal head were performed in the axial plane, using static volume contrast imaging in the C‐plane. The vermian perimeter, cross‐sectional area, and superoinferior diameter were measured and compared between abnormal and normal fetuses using the Wilcoxon nonparametric test. Linear regression analysis was used to describe trends of the vermis during gestation. The z scores for perimeter, cross‐sectional area, and superoinferior diameter measurements in the abnormal posterior fossa group in each 2‐week interval were calculated.
Results
Twelve fetuses with an abnormal posterior fossa were recruited: 3 with a Blake pouch cyst, 1 vermian cyst, 1 enlarged cisterna magna, 2 Dandy‐Walker malformation, 4 partial vermian agenesis, and 1 hemicerebellar hypoplasia. The vermian cross‐sectional area was reduced significantly in the fetuses with an abnormal posterior fossa compared with the control fetuses starting at 18 to 19 weeks' gestation (P = .01); the mean vermian superoinferior diameter was lower only from 22 to 23 weeks (P = .01); and the mean vermian perimeter was decreased from 28–29 weeks' gestation (P = .03). Linear regression analysis of the parameters showed that fetuses with an abnormal posterior fossa had a statistically significantly lower growth rate than control fetuses during gestation (P < .001).
Conclusions
Measurements of the cross‐sectional area were more useful than those of the perimeter and superoinferior diameter in distinguishing between fetuses with a normal and an abnormal posterior fossa during the early stages of gestation.
These findings suggest that L-arginine infusion affects utero-placental circulation in patients with IUGR associated with increased uterine resistances. Such an action is specific and appears possibly to be mediated by a release of nitric oxide.
BACKGROUND AND PURPOSE:Normal biometry of the fetal posterior fossa rules out most major anomalies of the cerebellum and vermis. Our aim was to provide new reference data of the fetal vermis in 4 biometric parameters by using 3 imaging modalities, 2D ultrasound, 3D ultrasound, and MR imaging, and to assess the relation among these modalities.
Cell-free fetal DNA in maternal plasma or serum is at present widely investigated as a source of fetal genetic material, both in studies of pregnancy-related disorders and in planning strategies for non-invasive prenatal diagnosis. Despite the number of trials already performed on the quantitation of fetal DNA, data about the amount of DNA at the beginning of pregnancy, in particular in the first trimester, remain limited. A new probe mapping on the deleted in azoospermia (DAZ) repetitive region of the Yq chromosome was designed for an early assessment of fetal DNA concentration in maternal serum. Among 57 pregnant women prospectively studied in their first trimester, fetal DNA was detected already by the 5th gestational week, with the analysis becoming reliable by the 8th week of gestation when a 100% accuracy in fetal sex determination was achieved. Moreover, in the three cases of pregnancy ending in fetal loss, the amount of fetal DNA apparently decreased before the abortion was diagnosed, whereas it consistently showed an increasing trend in normal pregnancies. Real-time PCR with the use of DAZ multilocus probe can efficiently quantitate free fetal DNA in the maternal serum at the beginning of pregnancy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.