Validation of aortic valve pressure gradient quantification using semi-automated 4D flow CMR pipeline

Area of Science:

• Cardiovascular Imaging
• Medical Diagnostics
• Biomedical Engineering

Background:

• Doppler echocardiography is standard for assessing aortic stenosis severity via aortic valve (AV) peak velocity and pressure gradients.
• Four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) shows potential for estimating AV pressure gradients, but current methods are complex.
• A validated, streamlined approach for 4D flow CMR assessment is needed.

Purpose of the Study:

• To validate a novel semi-automated 4D flow CMR pipeline for assessing aortic valve pressure gradient (AVPG).
• To compare the accuracy of this 4D flow CMR method against invasive pressure measurements.
• To evaluate the utility of 4D flow CMR as a complementary diagnostic tool for aortic stenosis.

Main Methods:

• 11 patients with severe aortic stenosis underwent pre-intervention Doppler echocardiography, invasive cardiac catheterization, and 4D flow CMR.
• A novel semi-automated pipeline using CAAS MR Solutions software was applied to 4D flow CMR data.
• Peak pressure gradients were calculated using both invasive methods and the 4D flow CMR pipeline.

Main Results:

• The invasive method yielded a peak AVPG of 51.9 ± 35.2 mmHg.
• The semi-automated 4D flow CMR pipeline calculated a peak AVPG of 52.2 ± 29.2 mmHg.
• A good correlation (r=0.70, p=0.017) was observed between 4D flow CMR and invasive assessments.

Conclusions:

• The novel semi-automated 4D flow CMR pipeline accurately assesses AVPG.
• This 4D flow CMR method demonstrates excellent agreement with invasive assessments.
• 4D flow CMR is a valuable complementary tool to echocardiography for diagnosing aortic stenosis.