Comparison of aortic blood flow rotational direction in healthy volunteers and patients with bicuspid aortic valves using volumetric velocity-sensitive cardiovascular magnetic resonance imaging

Sebastian Ebel; Benjamin Köhler; Abhinav Aggarwal; Bernhard Preim; Benjamin Behrendt; Bernd Jung; Robin F Gohmann; Boris Riekena; Michael Borger; Philipp Lurz; Timm Denecke; Matthias Grothoff; Matthias Gutberlet

doi:10.21037/qims-23-183

Comparison of aortic blood flow rotational direction in healthy volunteers and patients with bicuspid aortic valves using volumetric velocity-sensitive cardiovascular magnetic resonance imaging

Quant Imaging Med Surg. 2023 Dec 1;13(12):7973-7986. doi: 10.21037/qims-23-183. Epub 2023 Oct 27.

Authors

Affiliations

¹ Department of Diagnostic and Interventional Radiology, University of Leipzig - Heart Centre, Leipzig, Germany.
² Department of Diagnostic and Interventional Radiology, University of Leipzig, Leipzig, Germany.
³ Department of Simulation and Graphics, University of Magdeburg, Magdeburg, Germany.
⁴ Department of Radiology, Saral Diagnostics, New Delhi, India.
⁵ Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Bern, Switzerland.
⁶ Department of Cardiac Surgery, University Leipzig - Heart Centre, Leipzig, Germany.
⁷ Department of Cardiology, University Leipzig - Heart Centre, Leipzig, Germany.

^# Contributed equally.

Abstract

Background: The rotational direction (RD) of helical blood flow can be classified as either a clockwise (RD⁺) or counter-clockwise (RD^-) flow. We hypothesized that this simple classification might not be sufficient for analysis in vivo and a simultaneous existence of RD^+/- may occur. We utilized volumetric velocity-sensitive cardiovascular magnetic resonance imaging (4D flow MRI) to analyze rotational blood flow in the thoracic aorta.

Methods: Forty volunteers (22 females; mean age, 41±16 years) and seventeen patients with bicuspid aortic valves (BAVs) (9 females; mean age, 42±14 years) were prospectively included. The RDs and the calculation of the rotating blood volumes (RBVs) in the thoracic aorta were performed using a pathline-projection strategy.

Results: We could confirm a mainly clockwise RD in the ascending, descending aorta and in the aortic arch. Furthermore, we found a simultaneous existence of RD⁺/RD^-. The RD^+/--volume in the ascending aorta was significantly higher in BAV patients, the mean RD⁺/RD^- percentage was approximately 80%/20% vs. 60%/40% in volunteers (P<0.01). The maximum RBV always occurred during systole. There was significantly more clockwise than counter-clockwise rotational flow in the ascending aorta (P<0.01) and the aortic arch (P<0.01), but no significant differences in the descending aorta (P=0.48).

Conclusions: A simultaneous occurrence of RD⁺/RD^- indicates that a simple categorization in either of both is insufficient to describe blood flow in vivo. Rotational flow in the ascending aorta and in the aortic arch differs significantly from flow in the descending aorta. BAV patients show significantly more clockwise rotating volume in the ascending aorta compared to healthy volunteers.

Keywords: Volumetric velocity-sensitive cardiovascular magnetic resonance imaging (4D flow MRI); aortic blood flow; bicuspid aortic valve (BAV); helical blood flow; rotating blood volume (RBV); rotational direction (RD).