Two-minute k-space and time–accelerated aortic fourdimensional flow MRI: Dual-center study of feasibility and impact on velocity and wall shear stress quantification

Emilie Bollache, Kristopher D. Knott, Kelly Jarvis, Redha Boubertakh, Ryan Scott Dolan, Claudia Camaioni, Louise Collins, Paul Scully, Sydney Rabin, Thomas Treibel, James C. Carr, Pim Van Ooij, Jeremy D. Collins, Julia Geiger, James C. Moon, Alex J. Barker, Steffen E. Petersen, Michael Markl*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Purpose To investigate the two-center feasibility of highly k-space and time (k-t)–accelerated 2-minute aortic four-dimensional (4D) flow MRI and to evaluate its performance for the quantification of velocities and wall shear stress (WSS).  Materials and Methods This cross-sectional study prospectively included 68 participants (center 1, 11 healthy volunteers [mean age ± standard deviation, 61 years ± 15] and 16 patients with aortic disease [mean age, 60 years ± 10]; center 2, 14 healthy volunteers [mean age, 38 years ± 13] and 27 patients with aortic or cardiac disease [mean age, 78 years ± 18]). Each participant underwent highly accelerated 4D flow MRI (k-t acceleration, acceleration factor of 5) of the thoracic aorta. For comparison, conventional 4D flow MRI (acceleration factor of 2) was acquired in the participants at center 1 (n = 27). Regional aortic peak systolic velocities and three-dimensional WSS were quantified.  Results k-t–accelerated scan times (center 1, 2:03 minutes ± 0:29; center 2, 2:06 minutes ± 0:20) were significantly reduced compared with conventional 4D flow MRI (center 1, 12:38 minutes ± 2:25; P <.0001). Overall good agreement was found between the two techniques (absolute differences ≤15%), but proximal aortic WSS was significantly underestimated in patients by using k-t–accelerated 4D flow when compared with conventional 4D flow (P ≤.03). k-t–accelerated 4D flow MRI was reproducible (intra- and interobserver intraclass correlation coefficient ≥0.98) and identified significantly increased peak velocities and WSS in patients with stenotic (P ≤.003) or bicuspid (P ≤.04) aortic valves compared with healthy volunteers. In addition, k-t–accelerated 4D flow MRI–derived velocities and WSS were inversely related to age (r ≥−0.53; P ≤.03) over all healthy volunteers.  Conclusion k-t–accelerated aortic 4D flow MRI providing 2-minute scan times was feasible and reproducible at two centers. Although consistent healthy aging- and disease-related changes in aortic hemodynamics were observed, care should be taken when considering WSS, which can be underestimated in patients.

Original languageEnglish (US)
Article numbere180008
JournalRadiology: Cardiothoracic Imaging
Issue number2
StatePublished - Jun 2019

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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