Highly Accelerated Aortic 4D Flow MRI: Implications for Pulse Wave Velocity Measurements

Area of Science:

• Cardiovascular imaging
• Biomarker quantification
• Magnetic Resonance Imaging (MRI)

Background:

• Aortic pulse wave velocity (PWV) is a key biomarker for arterial stiffness.
• Compressed sensing (CS)-accelerated 4D flow MRI offers reduced scan times.
• The impact of CS acceleration on PWV measurement consistency is not well understood.

Purpose of the Study:

• To assess PWV calculation method consistency across varying CS acceleration factors (R).
• To identify the most robust PWV measurement method under CS acceleration.
• To investigate the specific effects of CS acceleration on PWV values.

Main Methods:

• Prospective study involving 16 healthy adults (23-39 years).
• Utilized a 3D Cartesian retrospective ECG-triggered 4D flow sequence at 3T.
• Acquired data with GRAPPA (R=2) and CS (R=4.4 to 20.5); PWV calculated using five methods (TTf, TTm, Xcor, plane, MLE).

Main Results:

• All CS reconstructions showed systematic PWV overestimation compared to GRAPPA R=2 (bias +7.7% to +50.5%).
• The time-to-foot (TTf) method exhibited the largest overestimation.
• The cross-correlation (Xcor) method demonstrated minimal bias and highest scan-rescan repeatability (ICC up to 0.94).

Conclusions:

• CS accelerated 4D flow MRI leads to PWV overestimation compared to standard GRAPPA.
• The Xcor method offers the most reliable and consistent PWV measurements, even at high CS acceleration factors.
• Xcor method may facilitate more consistent arterial stiffness assessment using accelerated 4D flow MRI.