from 02:00 PM to 03:00 PM
BRIC—Radiology Faculty Candidate Seminar
Challenges and Opportunities in Human MR Imaging at Ultrahigh Fields: an RF Perspective
Tuesday, February 19th 2013 2:00PM – 3:00PM
Presented in the Medical Research Building D Conference Room
High (e.g. 3 and 4T) and ultrahigh magnetic fields (e.g. 7, 8 and 9.4T) for human MR applications have been advocated due to their intrinsically high signal-to-noise ratio (SNR) and spectral dispersion. A major challenge to fully realize such high-field advantages is the design of high-frequency RF coils, especially large volume coils and parallel imaging transceiver arrays, which determines the feasibility of in vivo MR studies at ultra-high fields. In addition, the high frequency wave behavior of the B1+/B1- fields in the conductive and high dielectric samples (such as human body) causes inhomogeneous signal distributions. In this talk, we will discuss the problems faced in high frequency coil designs, such as increased radiation losses, degraded sensitivity, image inhomogeneity, complex wave behaviors, high operating frequency limitations, and also the solutions using the newly developed microstrip transmission line (MTL) coil design method and their in vivo applications. The coil design examples will cover surface coils, volume coils, parallel imaging transceiver arrays and dual-tuned coils. Parallel transmit using multichannel transceiver arrays for B1 shimming and selective excitation will be also discussed.