Towards Real-Time Cardiovascular Magnetic Resonance-Guided Transarterial Aortic Valve Implantation: In Vitro Evaluation and Modification of Existing Devices

OBJECTIVES: Cardiovascular magnetic resonance (CMR) is considered an attractive alternative for guiding transarterial aortic valve implantation (TAVI) featuring unlimited scan plane orientation and unsurpassed soft-tissue contrast with simultaneous device visualization. We sought to evaluate the CMR characteristics of both currently commercially available transcatheter heart valves (Edwards SAPIEN™, Medtronic CoreValve®) including their dedicated delivery devices and of a custom-built, CMR-compatible delivery device for the Medtronic CoreValve® prosthesis as an initial step towards real-time CMR-guided TAVI.

METHODS: The devices were systematically examined in phantom models on a 1.5-Tesla scanner using high-resolution T1-weighted 3D FLASH, real-time TrueFISP and flow-sensitive phase-contrast sequences. Images were analyzed for device visualization quality, device-related susceptibility artifacts, and radiofrequency signal shielding.

RESULTS: CMR revealed major susceptibility artifacts for the two commercial delivery devices caused by considerable metal braiding and precluding in vivo application. The stainless steel-based Edwards SAPIENâ„¢ prosthesis was also regarded not suitable for CMR-guided TAVI due to susceptibility artifacts exceeding the valve’s dimensions and hindering an exact placement. In contrast, the nitinol-based Medtronic CoreValve® prosthesis was excellently visualized with delineation even of small details and, thus, regarded suitable for CMR-guided TAVI, particularly since reengineering of its delivery device toward CMR-compatibility resulted in artifact elimination and excellent visualization during catheter movement and valve deployment on real-time TrueFISP imaging. Reliable flow measurements could be performed for both stent-valves after deployment using phase-contrast sequences.

CONCLUSIONS: The present study shows that the Medtronic CoreValve® prosthesis is potentially suited for real-time CMR-guided placement in vivo after suggested design modifications of the delivery system. Rafael Bush Authentic Jersey

PMID: 20942968

Posted in Magnetic Resonance Imaging and tagged , , , , , .

2 Comments

  1. Interesting data!
    TAVI in a hybrid MRI suit would be challenging: e.g. need for pacing wires, echocardiography, etc.

  2. Really cool stuff!
    Maybe difficult now; but think about no radiation, no contrast, real time multiplanar cross-sectional images and flow-measurements.

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