4D Flow MRI-Based Quantification of Tricuspid Regurgitation: A Possible Approach to Improve Measurement Repeatability

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Radiology

Background:

• Tricuspid regurgitation (TR) quantification is challenging with current MRI and TTE methods.
• Limitations exist in accurately measuring TR volume (TR _V ).

Purpose of the Study:

• To introduce and evaluate a novel 4D Flow MRI technique for direct TR _V quantification.
• This method utilizes retrospective tricuspid valve (TV) annular tracking.

Main Methods:

• Prospective enrollment of 30 patients with TR.
• Quantification of TR _V using four MRI methods: indirect, 2D phase-contrast, 4D Flow with static TV plane, and 4D Flow with dynamic annular tracking.
• Assessment of reproducibility and agreement with standard MRI and TTE methods.

Main Results:

• The dynamic 4D Flow method demonstrated strong correlation with other MRI techniques (r=0.77-0.81) but yielded higher TR _V values.
• Excellent inter-observer reproducibility was observed (r=0.99, kappa=0.80).
• Agreement in TR severity grading was poor across methods, with dynamic 4D Flow classifying more cases as moderate/severe; agreement with TTE was slight (kappa=0.17).

Conclusions:

• 4D Flow MRI with dynamic TV tracking provides a reproducible and potentially more sensitive method for TR _V quantification.
• This technique may overcome limitations of conventional MRI and TTE, improving TR clinical evaluation.
• The method shows promise for assessing complex TR cases despite limited alignment with TTE findings.