Nuchal translucency measurement: training of potential examiners

The aim of this study was to assess a training regimen for nuchal translucency measurement by transabdominal (TAS) and transvaginal sonography (TVS). After initial instruction regarding the criteria for correct nuchal translucency measurement, trainees (A and B) and an experienced examiner (C) performed nuchal translucency measurements on fetuses of 10-13 weeks' gestation, and the trainees' ability to obtain a measurement, repeatability and levels of agreement were assessed. In addition, a further experienced examiner (D) performed nuchal translucency measurements to validate the training regimen. Examiner C obtained nuchal translucency measurements in 94% by TAS, 93% by TVS and 100% by a combination of both scan modes. The repeatability coefficient was 0.40 mm and 0.24 mm for TAS and TVS, respectively. Trainees A and B were considered trained after 80 and 100 scans with TAS and TVS, respectively. They were considered trained when they could consistently obtain measurements that were of comparable repeatability and comparable levels of agreement with those of examiner C. The trainees' difficulties with TAS were in achieving satisfactory repeatability and levels of agreement, but with TVS it was ability in obtaining a measurement. We propose the training methods, standards and criteria used in this study as the basis for training sonographers in nuchal translucency measurements.