Learning curve for fetal postmortem ultrasound

Objective: To determine the learning curve of fetal postmortem ultrasound (PMUS) and evaluate the evolution of its diagnostic performance over the past 8 years.Methods: PMUS was performed by two fetal medicine specialists and two experts on 100 unselected fetuses of 12-38 weeks of gestation in a prospective, double-blind manner. 21 pre-defined internal structures were analyzed consecutively by the trainee alone and the expert, with a comparison of diagnosis and immediate feedback. The learning curves for examination duration, non-recognition of structures and final diagnoses were computed using cumulative summation analysis. Secondly, the expert PMUS diagnostic accuracy using autopsy as the gold standard was compared to the previously published data.Results: The trainees reached expert level of PMUS at 28-36 cases for examination duration (12.1 +/- 5.2 min), non-diagnostic rate (6.5%, 137/2100), and abnormality diagnosis. In a group of 33 fetuses >= 20 weeks who had an autopsy, the experts PMUS performance was improved after 8 years with a reduction of all organs non-diagnostic rate (6.5 %VS 11.4%, p < 0.01) and higher sensitivity for the heart (100% VS 40.9%, p < 0.01) and the abdomen (100%VS 56.5%, p < 0.05).Conclusion: PMUS offers a short learning curve for fetal medicine specialists and on-going improvement of diagnostic accuracy over time.