Results
SECONDARY
At the start of SVRIII, 313 patients were eligible for enrollment, and 237 patients enrolled with a median age of 10.76 years [IQR 10.28, 11.35] at the time of consent, Fig. This is a flow chart demonstrating the breakdown of eligible patients enrolled in SVR III and the total number of CMR exams with adequate imaging for measurement of right ventricular ejection fractionprovides reasons enrolled participants did not undergo a CMR examThe 177 CMR studies were performed at sites with scanners from three vendors: GE (18 exams), Philips (87 exams), and Siemens (72 exams). 135/177 (76%) studies were performed for the purpose of research only, without sedation or contrast. There were 42/177 (24%) studies performed for a clinical indication. There were 29/177 (16%) total studies performed using a gadolinium contrast agent. There were 10/177 (6%) total studies performed under generalized endotracheal tube anesthesia (This figure demonstrates the distribution of study quality for all CMR exams performed in the SVR III studydemonstrates the study quality grade and the type of artifacts noted in studies with that grade. The number in parentheses indicates the number of studies noted to have that artifactThe median total exam time was 54 min [IQR 40, 74]. There was high variability in the total exam time—minimum 8 min and maximum 154 min. The variability was secondary to sites adding LGE imaging or other pulse sequences to the base required exam, which is expected with the addition of imaging and contrast injection. Short exam times were from aborted studies or limited studies due to artifact. The median time to acquire adequate SSFP cine images for the primary outcome measure was 20 min [IQR 14, 27]. Similarly, the time for phase contrast image acquisition was 18 min [IQR 12, 25].