The development of the birdcage resonator: a historical perspective

The author gives a personal account of the development of the birdcage resonator while he worked at GE Medical Systems. The emphasis is on promoting an intuitive understanding of the underlying principles of RF coil design by recounting the assumptions, misconceptions, and reasoning involved in addressing the challenging problems in a new field of technology. Topics covered include the historic context of early MRI development, the critical role of RF coil technology in high field imaging, the need for an RF shield, the importance of distributed capacitance, the scientific controversies over magnetic field strength for imaging, a comparison of the birdcage design to an earlier Technicare phased coil, the distribution of electric fields in birdcage resonators, and the limitations of birdcages at very high fields. The author often cites less well-known patent literature on RF coil technology.