Recent studies found that chromosomal abnormalities occur much

more frequently than is generally appreciated. It is estimated that

approximately one of 200 newborn infants has some form of

chromosomal abnormality.

Intrauterine detection of congenital anomalies is of paramount

importance for the family and the community. A thickened nuchal

translucency (NT) is a powerful marker for chromosomal abnormalities

and is also associated with many structural fetal defects. The excellent

track record of the first-trimester nuchal evaluation in detecting fetuses

with Down syndrome and other defects has cemented this biometric

assessment as a standard part of the first trimester sonogram.

Nuchal translucency measurement should follow strict guidelines

and holding ongoing audit.

Summary

The major advantages of 3D ultrasound are the ability to

obtain ultrasound section which is impossible to be seen on a

routine scan, and the ability to perform accurate volume

measurements. In addition, 3D anatomical reconstruction of the

organs of interest is possible

The current study used a novel technique of measuring the

NV by VOCAL aiming to determine whether nuchal volume can

replace nuchal translucency thickness in first trimester screening of

chromosomal defects using 3D ultrasound.

This prospective study was held at Obstetrics and Gynecology

Department, Benha University Hospital, from February, 2010 till

November, 2010 on 100 consequent uncomplicated, singleton

pregnant females who underwent NT scanning at 11–13 + 6

weeks of gestation by 2D and 3D ultrasound.

The present study found that mean the NT measured by 2D

was 1.3mm + 0.5. Also, the study found no statistically significant

difference between the measurements of CRL, BPD and NT by

2D and those measured on the stored 3D volume data.

Suggesting that 3D ultrasound can replace conventional 2D

scanning.

This study found that the mean NV was 0.66cc. NV was found

to be correlated to gestational age (11-13+6 weeks) and NT.

The study concluded that NV can replace NT in first trimester

chromosomal scan.

More studies including larger number of patients are needed

to generate a normal standard curve.