Accuracy of flow volume estimation in the dilated aorta using 4D flow MRI: a pulsatile phantom study

Area of Science:

• Biomedical Engineering
• Cardiovascular Imaging
• Fluid Dynamics

Background:

• Aortic dilatation, including aneurysms, poses a rupture risk.
• Hemodynamic assessment via 4D flow CMR is promising but needs validation in complex flow.
• Accurate flow measurement is crucial for managing aortic pathologies.

Purpose of the Study:

• To develop an in vitro system for CMR-compatible assessment of flow in dilated aortas.
• To validate the accuracy of 4D flow CMR for volume flow measurements in aneurysmal models.
• To compare 4D flow CMR measurements with reference methods.

Main Methods:

• Manufactured latex aortic aneurysm models (ascending and abdominal).
• Utilized a pulsatile flow system with a pneumatic piston and elastic membrane pump.
• Employed 4D flow CMR to measure flow volume and rate, compared against gravimetric methods and 2D flow.

Main Results:

• 4D flow CMR demonstrated low errors in flow volume assessment (<2 ml mean difference, <4% relative difference).
• Flow volume estimations by 4D flow and 2D flow were comparable (p>0.05).
• Peak flow rates in dilated regions mirrored patient observations.

Conclusions:

• The in vitro system successfully validated 4D flow CMR accuracy for flow volume in dilated aortas.
• 4D flow CMR provides reliable hemodynamic assessment in complex flow patterns like aneurysms.
• This validation supports the clinical use of 4D flow CMR for aortic pathologies.