EP06.02: Automated measurement of nuchal translucency by volume NT™ (3D ultrasound): feasibility and reproducibility about 100 consecutive measurements by five physicians

Abstract

The purpose of this study is to evaluate the feasibility of volume NT™, a new technique that automatically archives mid-sagittal plane views and measures the maximum NT (Nuchal Translucency) distance, by comparing NT measurements with the conventional two (2D) and three dimensional (3D) techniques. The study population consisted of 100 consecutive singleton undergoing NT screening at 11–13+6 weeks gestation. Fetuses with enlarged NT and multiple anomalies were excluded. Volume NT™, 2D and 3D techniques were performed with Accuvix V20 Prestige (Samsung Medison Co). Four experienced operators participated in this study. Each operator manually measured the NT according to Herman score, FMF (Fetal Medecine Foundation) and with in to in assessment. Then through an approximated mid-sagittal section determined by conventional B-mode ultrasound, the operator obtained an NT automatically using Volume NT™ software. One less experienced operator blinded to 2D and 3D measurements of experts examined archive images of patients and obtained automatic measurement of the NT with Volume NT™ from in to in of the two echogenic lines delineating the NT. Among the 100 cases initially included in this study, 24 cases were excluded from analysis because of exclusion criteria (NT increased and multiple abnormalities n = 6) or missing data (n = 18). Median measure of 2D NT (1.3 mm (0.7 to 3.4)) was higher than in 3D (1.2 mm (0.6 to 3)) without significant difference, probably due to “In to In” assessment. 25 cases of 2D NT measurements were associated with a low Herman score (<6). 23 of these 25 cases were associated with better Herman score (≥6) using Volume NT and even those measured by the least experienced operator (p = 0.035). Volume NTTM helps to improve Herman score, whenever 2D NT assessment is difficult to get, by obtaining a better sagittal plane, even in the hands of a less experienced operator.