A test-retest multisite reproducibility study of cardiovascular four-dimensional flow MRI without respiratory gating

To systematically investigate the multisite reproducibility, test-retest reliability, and observer variability of non-respiratory-gated four-dimensional (4D) flow magnetic resonance imaging (MRI) in the thoracic great vessels for the assessment of blood flow and peak velocity.

Electrocardiogram (ECG)-gated 4D flow MRI data were acquired without respiratory gating in 10 healthy volunteers. To analyse multisite reproducibility, 4D flow was scanned at three different sites using a 3 T GE MRI machine with identical protocols for the group of participants. In addition, to evaluate test-retest reliability, the same volunteers were scanned in each centre during a second visit. Data analysis included calculation of peak systolic velocity and time-resolved and total flow of both the ascending aorta and pulmonary artery. Two observers conducted the above measurements to assess the interobserver variability.

Multisite, test-retest, interobserver agreement were good for the calculation of total flow and peak systolic velocity (mean differences <10% of the average flow parameter).

Non-respiratory-gated 4D MRI-based assessment of aortic and pulmonary blood flow can be performed with good reproducibility. It may facilitate the potential clinical application of this technique.