Prenatal ultrasound diagnosis and quality control of fetal nuchal translucency

In clinical ultrasound examinations, it is challenging to perform quality control on the images of each fetal nuchal translucency (NT) and crown-rump length (CRL). However, small measurement differences can increase the probability of false-positive or false-negative diagnosis. Therefore, it is necessary to establish a quality control system for fetal NT examination. This study aims to control the quality of fetal NT and CRL measurements, evaluate the accuracy of ultrasound physicians in early pregnancy NT measurements, and analyze the impact of increased fetal structure screening on the detection rate of chromosomal abnormalities. Data were collected from cases before and after 12 months of NT examination quality control, with 2 214 before quality control and 2 538 cases after quality control. Three quality control data metrics were analyzed: NT multiple of median (NT-MoM), standard deviation (SD) of log MoM [(SD) log MoM], and the slope of NT on CRL (SNC). The performance of NT measurements was monitored through the individual CRL NT-MoM within the 0.9-1.1 MoM range of the normal median curve, while grouped based on different years of experience (6 years), and NT-MoM values among these groups were compared. Data on NT thickening, structural anomalies, and chromosomal abnormalities were retrospectively analyzed during the quality control period. According to the curve equation of the American NTQR project group, the NT-MoM value before quality control was 0.921 7 MoM, the (SD) log MoM value was 0.091 92, and the SNC value was 12.20%. After quality control, the NT-MoM value was 0.948 3 MoM, the (SD) log MoM value was 0.094 81, and the SNC value was 11.43%. The comparison of NT-MoM values before and after quality control showed a statistically significant difference (