k-t accelerated multi-VENC 4D flow MRI improves vortex assessment in pulmonary hypertension

4D flow imaging can be used to evaluate vortex formation in the pulmonary artery seen in patients with pulmonary hypertension. We evaluated if a k-t accelerated multi-VENC (velocity encoding) 4D flow acquisition improves image quality, inter-reader agreement and correlation with hemodynamic parameters.A total of 14 patients with pulmonary hypertension (5 females, 9 males; mean age 61 ± 16 years) underwent 4D flow MRI (magnetic resonance imaging) and right heart catheterization. In addition to that, 13 healthy volunteers (2 females, 11 males, mean age 33 ± 12 years) also underwent 4D flow MRI. Multi- and single-VENC datasets were reconstructed and evaluated for vortex formation and vortex duration by two blinded readers and image quality was rated on a 5-point scale.Both readers rated image quality as significantly higher on multi-VENC datasets (3.96 ± 0.71 vs. 2.56 ± 0.93, p < 0.001; 4.70 ± 0.61 vs. 4.07 ± 0.92, p = 0.003). Inter-reader correlation for vortex duration quantification was higher on multi-VENC datasets compared to single-VENC datasets (r = 0.63 vs. r = 0.44). No significant correlation was found between vortex duration and mean pulmonary artery pressure in patients with PH.Multi-VENC 4D flow MRI significantly improves image quality and inter-reader agreement for the evaluation of vortex formation in the pulmonary artery.