Utilization of the nuchal translucency image-scoring method during training of new examiners

Training of new examiners, utilizing 1st-trimester nuchal translucency ultrasound screening, is mandatory for obtaining reproducible measurements. This study examined the contribution of the nuchal translucency image-scoring method to the process of training and its utilization as an objective tool of image evaluation and a tool for approving qualification. The study included an evaluation of the performance of two new examiners (examiners A and B) before and after intervention, using the image-scoring method. The preintervention period included 75 images evaluated by two reviewers using general evaluation and the scoring method. The report of the scoring method was submitted to the examiners and was applied to 55 images performed afterwards. The agreement between two reviewers in classifying the first 75 images as 'accepted' or 'rejected' was tested using general evaluation versus the scoring method. The effect of the intervention was examined by comparing the quality of the images between the two time periods. A chart indicating final scores of 80 successive images analyzed by examiner A was used to set criteria for assessing qualification. Using general evaluation, the reviewers disagreed on 19 (25%) of the images, whereas using the scoring method they disagreed on only 5 (7%, p < 0.01). Comparison before and after application of the intervention demonstrated significant improvement expressed by the increased rate of better quality groups (p < 0.001) and improved mean scores from 4.31 +/- 0.31 to 6.15 +/- 0.32 (p < 0. 001). Enhanced improvement of examiner's A performance could be attributed to the intervention rather than to his learning curve. Improvement was demonstrated in all the criteria examined; however, it was significant only for images size (from 33 to 98%), amnion demonstration (from 13 to 42%), and caliper placement (from 49 to 71%). Examiner's A chart enabled us to set standards for assessing competence, based on the scoring method. These included a minimum of 40 scans, followed by more than ten sequential images of acceptable quality. The scoring method contributed to the process of training, as it made possible to objectively evaluate the images, pointed out specific errors, served as an efficient tool of intervention, and might be used for ascertaining competence. We recommend to consider its utilization in centers running 1st-trimester ultrasound screening during training new examiners.