Single-loop coil concepts for intravascular magnetic resonance imaging

Compared with other coil designs that have been investigated for intravascu lar use, the single-loop coil can be designed with a very small diameter fo r insertion into small vessels and with a longitudinal extent over several centimeters for multislice imaging. If it designed to be expandable inside the target vessel, then it combines these features with increased signal-to -noise ratio (SNR) and penetration depth, Expandable single-loop coils that are capable of meeting these requirements were developed and integrated in to two different commercial catheter-based delivery systems: a self-expanda ble, single-loop made from NiTinol and a single-loop coil mounted an an inf latable balloon. The influence of a small-diameter coaxial cable for remote tuning and matching on the coil performance was investigated. Calculations showed the dependence of the signal on the separation between the conducto rs. The comparison of both catheter approaches in in vitro flow experiments and in an in vivo pig experiment revealed the influence of pulsatile flow on image quality during intravascular imaging with these designs. (C) 1999 Wiley-Liss, Inc.