Design of a birdcage array for lower extremity angiography

✍ Scribed by Ryan Brown; Martin R. Prince; Hale Ersoy; Michael Dooley; Bernard Y. Ho; Azma Mareyam; Kiyarash Mohajer; Yi Wang

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 696 KB
• Volume: 26
• Category: Article
• ISSN: 1053-1807
• DOI: 10.1002/jmri.21042

✦ Synopsis

Abstract

Purpose

To investigate the application of a coil array consisting of multiple birdcages for bolus chase magnetic resonance angiography (MRA) of the lower extremities.

Materials and Methods

The prototype consisted of four birdcage coils; two adjacent birdcages for thigh imaging, and two for calf imaging. Decoupling between adjacent coils was achieved using shared capacitors. Bench measurements and MR images were used to evaluate the decoupling scheme. Image signal‐to‐noise ratios (SNR) were compared between the birdcage array and four commercially available coils. Contrast‐enhanced imaging experiments were performed on 10 volunteers and parallel imaging was simulated. This study was approved by the local institutional review board and written informed consent was obtained from each volunteer.

Results

Capacitive decoupling resulted in a reduction in signal leakage. The calf birdcages provided an 84% SNR improvement over a four element array, while the thigh birdcages provided a 53% improvement. Angiographic images illustrated the utility of the coil for peripheral MRA. Parallel imaging was demonstrated with a two‐fold reduction factor.

Conclusion

Birdcage coils were demonstrated to be valuable for lower extremity imaging due to their homogenous sensitivity, good SNR, and cylindrical geometry. Coupling was controlled using shared capacitors that allowed a single birdcage to encompass each leg individually, providing a novel approach to signal reception for peripheral imaging. J. Magn. Reson. Imaging 2007. © 2007 Wiley‐Liss, Inc.