Lung coil for imaging hyper-polarized gas in an MRI scanner

A magnetic resonance imaging apparatus comprising:

• a main magnet for generating a main magnetic field through an examination region, said examination region having positioned therein a region of interest of a subject to be examined;
• a gradient coil assembly for generating magnetic gradients in the main magnetic field;
• a first RF coil tuned to a first Larmor frequency corresponding to a first species of nuclei;
• a first transmitter for transmitting RF signals at the first Larmor frequency;
• a first switch that electronically switches the first RF coil between (i) a transmit mode in which the first RF coil is electronically connected to the first transmitter for exciting resonance in the first species of nuclei disposed within the examination region, and, (ii) a receive mode in which the first RF coil is electronically connected to a first receiver channel for receiving and demodulating magnetic resonance signals emitted from excited first species nuclei as they relax;
• a second RF coil, said second RF coil being tuned, while the first RF coil is enabled, to a second Larmor frequency corresponding to a second species of nuclei, said second species being different from the first species;
• a second transmitter for transmitting RF signals at the second Larmor frequency;
• a second switch that electronically switches the second RF coil between (i) a transmit mode in which the second RF coil is electronically connected to the second transmitter for exciting resonance in the second species of nuclei disposed within the examination region, and (ii) a receive mode in which the second RF coil is electronically connected to a second receiver channel for receiving and demodulating magnetic resonance signals emitted from excited second species nuclei as they relax;
• and,
• a reconstruction processor connected with the first and second receiver channels for reconstructing the magnetic resonance signals from excited first species and second species nuclei into image representations;
• a sequence control circuit which operates the first and second switches such that the first RF coil is in the transmit mode when the second RF coil is in the transmit mode, and the first RF coil is in the receive mode when the second RF coil is in the receive mode.

A magnetic resonance imaging apparatus comprising:

• a main magnet for generating a main magnetic field through an examination region, said examination region having positioned therein a region of interest of a subject to be examined;
• a gradient coil assembly for generating magnetic gradients in the main magnetic field;
• a first RF coil tuned to a first Larmor frequency corresponding to a first species of nuclei;
• a first transmitter for transmitting RF signals at the first Larmor frequency;
• a first switch that electronically switches the first RF coil between (i) a transmit mode in which the first RF coil is electronically connected to the first transmitter for exciting resonance in the first species of nuclei disposed within the examination region, and, (ii) a receive mode in which the first RF coil is electronically connected to a first receiver channel for receiving and demodulating magnetic resonance signals emitted from excited first species nuclei as they relax;
• a second RF coil, said second RF coil being tuned, while the first RF coil is enabled, to a second Larmor frequency corresponding to a second species of nuclei, said second species being different from the first species;
• a second transmitter for transmitting RF signals at the second Larmor frequency;
• a second switch that electronically switches the second RF coil between (i) a transmit mode in which the second RF coil is electronically connected to the second transmitter for exciting resonance in the second species of nuclei disposed within the examination region, and (ii) a receive mode in which the second RF coil is electronically connected to a second receiver channel for receiving and demodulating magnetic resonance signals emitted from excited second species nuclei as they relax;
• and,
• a reconstruction processor connected with the first and second receiver channels for reconstructing the magnetic resonance signals from excited first species and second species nuclei into image representations;
• wherein at least one of the first and second RF coils includes at least one circuit which restricts it from supporting the Larmor frequency of the other.

A magnetic resonance method comprising:

• (a) introducing hyper-polarized gas into a region of interest of a subject being examined;
• (b) placing the region of interest of the subject being examined in a main magnetic field;
• (c) generating magnetic gradients in the main magnetic field across the region of interest;
• (d) simultaneously transmitting into the region of interests (i) RF signals having a frequency for exciting resonance in hydrogen dipoles and (ii) RF signals having a frequency for exciting resonance in hyper-polarized gas dipoles;
• (e) receiving signals emitted from the region of interest by both resonating hydrogen dipoles and resonating hyper-polarized gas dipoles;
• and,
• (h) reconstructing human viewable images of the region of interest from the received signals.

A magnetic resonance method comprising:

• (a) introducing hyper-polarized gas into a region of interest of a subject being examined;
• (b) placing the region of interest of the subject being examined in a main magnetic field;
• (c) generating magnetic gradients in the main magnetic field across the region of interest;
• (d) transmitting into the region of interest, via a first tuned coil, RF signals having a frequency for exciting resonance in hydrogen dipoles;
• (e) receiving, via the first tuned coil, signals emitted from the region of interest by resonating hydrogen dipoles;
• (f) transmitting into the region of interest, via a second tuned coil whose tuning accounts for a reactive coupling with the first tuned coil, RF signals having a frequency for exciting resonance in hyper-polarized gas dipoles;
• (g) receiving, via the second tuned coil, signals emitted from the region of interest by resonating hyper-polarized gas dipoles;
• and,
• (h) reconstructing human viewable images of the region of interest from the received signals;
• wherein the second tuned coil is tuned to the resonance frequency for the hyper-polarized gas dipoles while the first tuned coil is enabled.

A magnetic resonance method comprising:

• (a) introducing hyper-polarized gas into a region of interest of a subject being examined;
• (b) placing the region of interest of the subject being examined in a main magnetic field;
• (c) generating magnetic gradients in the main magnetic field across the region of interest;
• (d) transmitting into the region of interest, via a first tuned coil, RF signals having a frequency for exciting resonance in hydrogen dipoles;
• (e) receiving, via the first tuned coil, signals emitted from the region of interest by resonating hydrogen dipoles;
• (f) transmitting into the region of interest, via a second tuned coil whose tuning accounts for a reactive coupling with the first tuned coil, RF signals having a frequency for exciting resonance in hyper-polarized gas dipoles;
• (g) receiving, via the second tuned coil, signals emitted from the region of interest by resonating hyper-polarized gas dipoles;
• and,
• (h) reconstructing human viewable images of the region of interest from the received signals;
• wherein when the second tuned coil is set up for transmitting the first tuned coil is set up for transmitting and when the second tuned coil is set up for receiving the first tuned coil is set up for receiving.

A magnetic resonance apparatus having a main magnet for generating a magnetic field through an examination region, a first RF coil for transmitting and receiving signals at a resonance frequency of a first molecular species, and a second RF coil;

• the second RF coil being tuned to a resonance frequency of a second molecular species different from the first resonance frequency;
• circuitry in the second RF coil for preventing the second RF coil from supporting signals of the first species resonance frequency;
• and,
• circuitry in the first RF coil for preventing the first RF coil from supporting signals of the second species resonance frequency;
• wherein the first RF coil inductively couples to the second RF coil contributing a tuned frequency altering resonance to the second RF coil and further including:
• a tuning circuit for tuning the second RF coil with the resonance contributed by the first RF coil to the second species resonance frequency.

A The magnetic resonance apparatus having a main magnet for generating a magnetic field through an examination region, a first RF coil for transmitting and receiving signals at a resonance frequency of a first molecular species, and a second RF coil;

• the second RF coil being tuned to a resonance frequency of a second molecular species different from the first resonance frequency;
• circuitry in the second RF coil for preventing the second RF coil from supporting signals of the first species resonance frequency;
• and,
• circuitry in the first RF coil for preventing the first RF coil from supporting signals of the second species resonance frequency;
• wherein the first RF coil is tuned to the resonance frequency of 1H and th e second RF coil is tuned to the resonance frequency of a species other than 1H.