Normal range of intracranial translucency (IT) assessed by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks in a Chinese population

Abstract

Objectives: To establish the reference range of intracranial translucency (IT) in the first trimester in a Chinese population. Methods: In a prospective study from March 2007 to June 2007, three-dimensional (3D) volumes of the fetal profile in the mid-sagittal plane were recorded from 102 normal pregnancies screened for trisomy 21 by the combination of fetal nuchal translucency (NT) thickness, maternal serum free β-human chorionic gonadotropin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11 + 0 to 13 + 6 weeks. 3D volumes were examined using multiplanar techniques. In the mid-sagittal plane the fourth ventricle presents as an (IT between the brain stem and choroid plexus. The anteroposterior diameter of IT in each case was measured. The relationship between IT with the other parameter was also examined. Results: The IT at first trimester ranged from 1.35 to 2.6 mm. There was no significant association between IT with NT, and serum biochemistry. The intraobserver and interobserver agreement was assessed in 20 (19.6%) normal cases. Mean (SD) differences of two observers was −0.015 (0.132) mm (p > 0.05). For each observer, mean (SD) between the 2 paired measurements were −0.001 (0.097) mm, and 0.010 (0.085) mm, respectively (p > 0.05). Conclusions: In the first trimester, the reference range of IT in Chinese fetuses has been established. The assessment of IT is feasible and reproducible.