Four-Dimensional Computed Tomography-Guided Valve Sizing for Transcatheter Pulmonary Valve Replacement

Area of Science:

• Cardiovascular Imaging
• Medical Device Technology
• Anatomical Modeling

Background:

• Transcatheter pulmonary valve replacement (TPVR) prosthesis sizing relies on right ventricle (RV) and pulmonary artery (PA) measurements, which can vary significantly.
• Current 3D computed tomography (CT) imaging may not fully capture the dynamic displacement of the RV outflow tract (RVOT) and PA, increasing risks of stent misplacement and paravalvular leak.

Purpose of the Study:

• To develop and evaluate a dynamic 4D cardiac CT reconstruction model for precise RVOT-PA anatomical quantification throughout the cardiac cycle.
• To improve the accuracy of valve size selection for TPVR by utilizing dynamic anatomical data.

Main Methods:

• Pilot study using cardiac CT data from a sheep model (Sheep J).
• 3D CT data was reconstructed into an 11-frame 4D sequence to visualize cardiac motion.
• Measurements of diameter, cross-sectional area, and circumference were taken at key anatomical planes (PA, sinotubular junction, sinus, basal plane of pulmonary valve, RVOT) across all frames.
• Dynamic RV volume and right ventricular ejection fraction (RVEF) were also assessed.

Main Results:

• 4D CT measurements from the straightened model in Sheep J confirmed the same TPVR valve size (30 mm) as 3D CT measurements.
• The RVEF for Sheep J was measured at 62.1% using pre-procedural CT.
• The 4D model provided a more comprehensive assessment compared to 3D CT, enabling accurate valve size prediction.

Conclusions:

• The 4D cardiac CT reconstruction model offers a promising method for accurate valve size selection in TPVR.
• This dynamic modeling approach enhances visualization and quantification of RVOT-PA anatomy, potentially leading to improved TPVR outcomes and device innovation.