Creates Identical Spatial Profiles for Two Different Active Nuclei with High Efficiency and Minimal Losses
This dual nuclear magnetic resonance spectroscopy/magnetic resonance imaging (NMR/MRI)resonator operates with high efficiency on both the hydrogen nuclear frequency (1H) and the frequency of other NMR active nuclei (X).Magnetic resonance coils are radiofrequency devices that produce a radiofrequency magnetic field at the resonance frequency of the active nuclei, thereby causing nuclear spin state transitions on transmit. They also act as antennas to receive the radio signal the altered nuclei emit when they relax back to their original state. Most dual resonant coil designs involve modifying surface coils or birdcage coils with lossy LC trap circuits. In some designs, nested coils are used, with one operating on 1H and the other in X. These alterations degrade coil efficiency and often introduce uniformity issues in the RF magnetic field.
Researchers at the University of Florida have developed a dual resonant transmission line resonator coil that increases efficiency by completely eliminating the lossy LC trap circuit from the design while simultaneously resonating each coil element on both 1H and X. The design maybe applied to either surface or volume coils.
High-efficiency dual nuclear transmission line resonator applicable in any magnetic resonance application
- Eliminates lossy LC trap in design, increasing the efficiency of the dual resonant coil
- Does not use lumped constants in the active region of the coil, distributing capacitance and inductance uniformly
- Resonates both 1H and X simultaneously, ensuring that the resonator has the same spatial profile on both elements
- Isolates both 1H and X ports by 45 dB or better, allowing the two resonators to tune and match smoothly with no dynamic interaction between the two. In principle, simultaneous, independent transmit/receive operation on each nucleus is possible
- Is easy to use, aiding in rapid patient throughput in a clinical environment
- Adapts to array designs, digital transmit/receive architecture, and accelerated imaging schemes
- Especially applicable to hyperpolarized MRI work, clinical or spectroscopic
This dual nuclear coil is a transmission line resonator that functions on a wide array of MRI/NMR platforms. It operates simultaneously on the magnetic resonance frequency of 1H and one additional nucleus (X), such as phosphorous 31, carbon 13, helium 3, xenon 129, or sodium 23.Hybrid transmission notch filters and termination elements create a virtual short, isolating the RF energy at the 1H frequency from the X port while simultaneously isolating the RF energy at the X nucleus frequency from the 1H port. By configuring the hybrid transmission line termination elements and hybrid transmission line notch filters to serve as high efficiency, frequency dependent passive switches, no additional element, such as a MEMS device or PIN diode is required.