24: Inter-rater agreement of qualitative grading for fetal echocardiographic findings in twin-twin transfusion syndrome (TTTS)

points; 2nd and 3rd trimester scans were scored out of 27 possible points. Scans achieving a score 80% were considered passing; scans scoring 80% were considered failing and required submission of a supplemental scan. RESULTS: A total of 36 sonographers participated from 14 centers. Median sonographer experience performing obstetric ultrasounds was 12 years (range 3-30). Overall, 580 scans were submitted, of which 77.8% passed. More than 90% (20/22) of sonographers were required to submit 1 supplemental scan. Pass rates were significantly lower for initial submissions (74.7%; 349/467) than supplemental scans (90.3%; 102/113) (p 0.0005). Pass rates were similar for the three trimesters (1st: 80.6% [158/196]; 2nd: 77.5% [155/200]; 3rd: 75% [138/184]) (p 0.419). Figure 1 demonstrates the percentage of scans in which a deduction was made for select parameters. Of those sonographers who achieved credentialing in all trimesters (22/36; 61%), median time to full credentialing was 5.0 months (range 3-10). CONCLUSION: Intensive training and image review can be used to credential sonographers to perform standardized 2D ultrasounds of fetal biometry. Despite extensive prior experience, sonographers were often required to submit supplemental scans to demonstrate proper image acquisition and caliper placement.