Evaluation of Pulmonary Hypertension Using 4D Flow MRI

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Pulmonary Medicine

Background:

• Cardiac magnetic resonance imaging (MRI) is emerging as a non-invasive alternative to right heart catheterization (RHC) for pulmonary hypertension (PH) evaluation.
• Further research is needed to establish cardiac MRI's capability in characterizing PH.

Purpose of the Study:

• To assess the utility of four-dimensional (4D) flow MRI-derived pulmonary artery velocities for characterizing PH.
• To evaluate the correlation between these velocities and established PH metrics.

Main Methods:

• A prospective case-control study involving 54 PH patients and 25 controls.
• Utilized 1.5T 4D flow and cine MRI sequences to measure pulmonary artery velocities and cardiac volumes.
• Pulmonary vascular resistance (PVR) was derived from RHC, serving as a reference standard.

Main Results:

• Significantly lower peak and mean pulmonary artery velocities were observed in PAH patients compared to controls at the left and right pulmonary arteries.
• Pulmonary artery velocities showed significant correlations with right ventricular ejection fraction and end-systolic volume index.
• Moderate correlations were found between peak velocities and PVR in specific PH subgroups (PAH, PH-LHD, PH-CLD).

Conclusions:

• Four-dimensional (4D) flow MRI demonstrates potential for identifying pulmonary arterial hypertension (PAH).
• The technique shows promise in non-invasively tracking pulmonary vascular resistance (PVR) changes in PH patients.
• Further validation is warranted, particularly for chronic thrombo-embolic PH (CTE-PH).