Baseline 4D Flow-Derived in vivo Hemodynamic Parameters Stratify Descending Aortic Dissection Patients With Enlarging...

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Biomedical Engineering

Background:

• Type B aortic dissection (TBAD) poses significant risks, necessitating improved methods for predicting adverse outcomes and aortic growth.
• Traditional imaging modalities like MRA and CTA provide morphological data but may not fully capture the dynamic hemodynamic changes within the aorta.

Purpose of the Study:

• To evaluate the predictive value of true lumen (TL) and false lumen (FL) hemodynamics, compared to aortic morphology, for adverse-aorta related outcomes (AARO) and aortic growth in TBAD patients.
• To explore the utility of 4D flow MRI in assessing hemodynamic parameters relevant to TBAD progression.

Main Methods:

• Retrospective analysis of 51 patients with TBAD or residual TBAD (rTAAD) using 4D flow MRI.
• Manual segmentation of TL and FL from 4D flow MRI data to generate 3D hemodynamic maps.
• Comparison of hemodynamic parameters (kinetic energy, stasis, peak velocity, flow patterns) and aortic diameter between groups with and without AARO, and with different growth rates (≥3 mm/year vs. <3 mm/year).

Main Results:

• Patients with AARO exhibited larger baseline aortic diameters and altered FL and TL hemodynamics, including lower FL reverse flow and TL kinetic energy.
• In the de novo TBAD subgroup, AARO was associated with larger diameters, lower FL stasis, and lower TL peak velocity.
• A higher FL to TL kinetic energy ratio was observed in patients with aortic growth ≥ 3 mm/year in both the overall cohort and the de novo TBAD subgroup.

Conclusions:

• Four-dimensional flow MRI offers valuable hemodynamic insights into TBAD, potentially surpassing traditional imaging techniques.
• Hemodynamic assessment via 4D flow MRI can aid in the earlier identification of patients at higher risk for AARO and aortic growth.
• This advanced imaging technique holds promise for integrating into routine TBAD management, guiding timely interventions.