Hemodynamic Evaluation of Type B Aortic Dissection Using Compressed Sensing Accelerated 4D Flow MRI.

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Radiology

Background:

• Four-dimensional Flow Magnetic Resonance Imaging (4D Flow MRI) is crucial for assessing blood flow patterns.
• The impact of compressed sensing (CS) acceleration on aortic hemodynamic quantification in type B aortic dissection (TBAD) remains unclear.

Purpose of the Study:

• To compare the performance of CS-accelerated 4D Flow MRI against GRAPPA-accelerated 4D Flow MRI (GRAPPA) for evaluating aortic hemodynamics in TBAD patients.

Main Methods:

• Prospective study involving 12 TBAD patients and 2 volunteers using 1.5T 4D Flow MRI.
• Acquisitions included GRAPPA (R=2) and two CS accelerations (R=7.7 and R=10.2) for reproducibility assessment.
• Quantification of voxelwise kinetic energy (KE), peak velocity (PV), forward flow (FF), reverse flow (RF), and stasis, alongside plane-based mid-lumen flows.

Main Results:

• No significant differences in KE and FF in the true lumen (TL) or PV in the false lumen (FL) among acquisition types.
• GRAPPA showed higher PV and stasis in TL, and lower KE, FF, and RF in FL compared to CS accelerations.
• Moderate to excellent interscan reproducibility (ICC: 0.732-0.989) was observed, with strong correlations in TL (r: 0.781-0.986) and variable correlations in FL (r: 0.347-0.948).

Conclusions:

• CS-accelerated 4D Flow MRI offers potential clinical utility in TBAD due to reduced scan times.
• While overall hemodynamic trends are comparable, CS acceleration influences KE, FF, RF, and stasis, particularly within the FL.