Technical aspects of nuchal translucency measurement.

Nuchal translucency (NT) describes an echo-free area, below the skin, in the posterior nuchal and back region of the fetus and is typically observed in the first and early second trimester of pregnancy. A wide NT has been correlated with chromosomal and congenital abnormalities in the fetus. An accurate NT measurement is a critical component of the estimation of Down syndrome risk in the first trimester of pregnancy and the Nuchal Translucency Quality Review Program (NTQR) identified nine criteria that ensure an accurate measurement of NT during ultrasound examination. The purpose of this chapter is to present the technical aspects of obtaining an accurate NT measurement on ultrasound as outlined by the NTQR.