A novel method for coil efficiency estimation: Validation with a 13C birdcage

作者：Giovannetti Giulio^*; Frijia Francesca; Hartwig Valentina; Menichetti Luca; De Marchi Daniele; Positano Vincenzo; Landini Luigi; Lombardi Massimo; Santarelli Maria Filomena; Ardenkjaer Larsen Jan Henrik

来源：Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering , 2012, 41B(4): 139-143.

DOI：10.1002/cmr.b.21223

• B1 calibration
• radiofrequency coils
• coil efficiency
• dual-loop probe

Coil efficiency, defined as the B1 magnetic field induced at a given point on the square root of supplied power P, is an important parameter that characterizes both the transmit and receive performance of the radiofrequency (RF) coil. Maximizing coil efficiency will maximize also the signal-to-noise ratio. In this work, we propose a novel method for RF coil efficiency estimation based on the use of a perturbing loop. The proposed method consists of loading the coil with a known resistor by inductive coupling and measuring the quality factor with and without the load. We tested the method by measuring the efficiency of a 13C birdcage coil tuned at 32.13 MHz and verified its accuracy by comparing the results with the nuclear magnetic resonance nutation experiment. The method allows coil performance characterization in a short time and with great accuracy, and it can be used both on the bench and inside the scanner.

• 出版日期2012-10