[Fetal transcerebellar diameter measured in screening ultrasound: Feasibility and reproducibility]

The aim of the study was to evaluate feasibility and reproducibility of fetal transcerebellar diameter measurement during second and third trimester ultrasound mass screening by junior and senior physicians.

A monocentric prospective study was conducted at the tertiary care teaching hospital in Lyon, including patients undergoing their second or third trimester planned ultrasound exam. For each patient, a resident and a senior practitioner measured each fetal transcerebellar diameter, during a blinded experiment, according to the transcerebellar plane described by the International Society of Ultrasound in Obstetrics and Gynecology. Images have been scored on 4 criteria. The inter-observer variability for transcerebellar diameter and image quality was assessed using an intra-class correlation coefficient. Image quality has been analyzed according to pregnancy term and to fetal presentation.

Sixty-six patients were included, 44 patients before and 22 patients after 30 weeks. Inter-observer variability of transcerebellar diameter measurement was 0.4%. Inter-observer variability of image quality was 13.5%. Image quality was not significantly different between seniors and residents (P=0.06). Gestational age and fetal presentation did not affect significantly image quality (P=0.42) and (P=0.64) respectively.

Transcerebellar diameter measurement during mass screening is simple and reliable. Posterior fossa abnormalities can be explored through its measurement.