EP-4737932-A1 - A SYSTEM FOR IMAGING A HUMAN BREAST USING MAGNETIC RESONANCE IMAGING

EP4737932A1EP 4737932 A1EP4737932 A1EP 4737932A1EP-4737932-A1

Abstract

This disclosure relates to a system for imaging a human breast using magnetic resonance imaging, MRI. The system comprises a first antenna system comprising one or more linear antennas. Each linear antenna out of the one or more linear antennas is tuned to a first frequency and is configured to send excitation signals having the first frequency into the human breast for exciting nuclei of a first type that are present in the human breast and/or is configured to receive nuclear magnetic resonance, NMR, relaxation signals from the nuclei of the first type in the human breast. The system also comprises a second antenna system comprising one or more loop antennas. Each loop antenna is tuned to a second frequency that is different from the first frequency, and is configured to send excitation signals having the second frequency into the human breast for exciting nuclei of a second type that are present in the human breast, the second type being different from the first type and/or is configured to receive NMR relaxation signals from the nuclei of the second type in the human breast.

Inventors

Voogt, Ingmar Jacob
Gosselink, Wilhelmus Johannes Maria

Assignees

WaveTronica B.V.

Dates

Publication Date: 20260506
Application Date: 20241031

Claims (15)

A system for imaging a human breast using magnetic resonance imaging, MRI, the system comprising a first antenna system comprising one or more linear antennas, wherein each linear antenna out of the one or more linear antennas is tuned to a first frequency and is configured to send excitation signals having the first frequency into the human breast for exciting nuclei of a first type that are present in the human breast and/or is configured to receive nuclear magnetic resonance, NMR, relaxation signals from the nuclei of the first type in the human breast, and a second antenna system comprising one or more loop antennas, wherein each loop antenna is tuned to a second frequency that is different from the first frequency, and is configured to send excitation signals having the second frequency into the human breast for exciting nuclei of a second type that are present in the human breast, the second type being different from the first type, and/or is configured to receive NMR relaxation signals from the nuclei of the second type in the human breast.
The system according to any of the preceding claims, wherein the one or more linear antennas comprise at least two linear antennas and the one or more loop antennas comprise at least two loop antennas.
The system according to claim 1 or 2, wherein each linear antenna out of the one or more linear antennas is single-tuned, and wherein each loop antenna out of the one or more loop antennas is single-tuned.
The system according to any of the preceding claims, preferably according to at least claim 3, wherein the system does not comprise a tuning circuit with a PIN diode for tuning, by means of electrical signaling provided to the tuning circuit, any loop antenna out of the one or more loop antennas.
The system according to any of the preceding claims, wherein the first antenna system comprises a first antenna control system that is configured to cause at least one linear antenna out of the one or more linear antennas to send excitation signals for exciting nuclei of the first type that are present in the human breast and to process the NMR relaxation signals from the nuclei of the first type as received by the at least one linear antenna, and wherein the second antenna system comprises a second antenna control system that is configured to cause at least one loop antenna out of the one or more loop antennas to send excitation signals for exciting nuclei of the second type that are present in the human breast and to process the NMR relaxation signals from the nuclei of the second type as received by the at least one loop antenna.
The system according to any of the preceding claims, wherein the nuclei of the first type are 1H nuclei.
The system according to any of the preceding claims, wherein the nuclei of the second type are 31P nuclei.
The system according to any of the preceding claims, wherein the system comprises a volume for accommodating the human breast, wherein the one or more linear antennas and the one or more loop antennas are positioned around the volume.
The system according to claim 8, wherein each linear antenna out of the one or more linear antennas is bent around at least part the volume.
The system according to any of the preceding claims, wherein each loop antenna comprises a conductor loop that comprises a first part and a second part, which first part and second part lie in respective different planes that make an angle with each other.
The system according to any of the preceding claims, wherein each loop antenna comprises a or the conductor loop that is kinked at a plurality of positions along the conductor loop.
The system according to any of the preceding claims, wherein the one or more loop antennas comprises a or the first loop antenna and a or the second loop antenna, wherein the first loop antenna comprises a first conductor loop and the second loop antenna comprises the second conductor loop, wherein the firs conductor loop and second conductor loop at least partially overlap each other.
The system according to any of the preceding claims, wherein each linear antenna out of the one or more linear antennas comprises a meandering conductor.
A method for imaging a human breast using magnetic resonance imaging, MRI, with the system according to any of the preceding claims, the method comprising during a first time period, the first antenna system sending excitation signals having the first frequency to the human breast herewith exciting nuclei of the first type that are present in the human breast, and during a second time period after the first time period, the first antenna system receiving NMR relaxation signals from the nuclei of the first type, and during a third time period, the second antenna system sending excitation signals having the second frequency to the human breast herewith exciting nuclei of the second type that are present in the human breast, and during a fourth time period after the third time period, the second antenna system receiving NMR relaxation signals from the nuclei of the second type.
The method according to claim 14, wherein during the first and second time period, each loop antenna of the one or more loop antennas remains tuned to the second frequency, and during the third and fourth time period, each linear antenna of the one or more linear antennas remains tuned to the first frequency.

Description

FIELD OF THE INVENTION This disclosure relates to a system for imaging a human breast using magnetic resonance imaging (MRI), in particular so such system that comprises a first antenna system for detecting a first type of nuclei and a second antenna system for detecting a second type of nuclei. BACKGROUND MRI is a valuable technique for detection and analysis of compounds that are present in cancerous breast tissue. US2009/0118611 A1 describes a unified heteronuclear coil system that includes a volume coil tuned to detect a first nuclei and a butterfly coil to detect a second nuclei. A disadvantage of the system is that its detection accuracy and detection sensitivity are quite limited. SUMMARY One aspect of this disclosure relates to a system for imaging a human breast using magnetic resonance imaging, MRI. The system comprises a first antenna system comprising one or more linear antennas. Each linear antenna out of the one or more linear antennas is tuned to a first frequency and is configured to send excitation signals having the first frequency into the human breast for exciting nuclei of a first type that are present in the human breast and/or is configured to receive nuclear magnetic resonance, NMR, relaxation signals from the nuclei of the first type in the human breast. The system also comprises a second antenna system comprising one or more loop antennas. Each loop antenna is tuned to a second frequency that is different from the first frequency, and is configured to send excitation signals having the second frequency into the human breast for exciting nuclei of a second type that are present in the human breast, the second type being different from the first type and/or is configured to receive NMR relaxation signals from the nuclei of the second type in the human breast. This system is advantageous in that it allows to detect both nuclei of the first type and nuclei of the second type in one scan session. The first antenna system can send and receive signals for detecting nuclei of the first type and the second antenna system can send and receive signals for detecting nuclei of the second type. Linear antennas are especially suitable for sending and receiving signals for detection of 1H nuclei. The system is further advantageous in that it is relatively easy to design a configuration of one or more linear antennas and one or more loop antennas in which the linear antennas and loop antennas are not, or only to a limited degree, electromagnetically coupled to each other. Typically, such configuration can be achieved by positioning each linear antenna at some minimum distance from any conductor of any loop antenna. This is often very well possible as linear antennas have an elongated shape, while loop antennas comprise respective conductor loops. Hence, it is typically possible to position a loop such that it at least partially surrounds a linear antenna, at least as viewed from one point of view. Mutual coupling between antennas is an intricate phenomenon and is undesired for a variety of reasons. A first reason is that electromagnetic coupling between linear antenna and loop antenna typically introduces noise and therefore reduces the signal to noise ratios of the linear antenna as well as the loop antenna. A second reason is that such electromagnetic coupling may cause power transfer from a linear antenna to a loop antenna when the linear antenna is sending excitation signals, and may cause power transfer from a loop antenna to a linear antenna when the loop antenna is sending excitation signals. Such power transfer is undesired, not only because it may damage the loop antennas or signal processing hardware connected to the loop antenna and/or to the linear antenna, but also because it may increase the specific absorption rate (SAR) of the system which comes with a risk of damaging breast tissue and/or skin tissue. Preferably, any electromagnetic coupling between any of the one or more loop antennas and any of the one or more linear antennas is less than -10 dB, preferably less than -20 dB, more preferably less than -25 dB. It would be more complex to design a system having a first second antenna system comprising one or more loop antennas tuned to the first frequency and a second antenna system comprising one or more loop antennas tuned to the second frequency wherein the loop antennas of the first coil system would not be coupled, or coupled only to a limited extent, to loop antennas of the second coil system. This is especially true if the first coil system would comprise more than one loop antenna and the second loop antenna would comprise more than one loop antenna. A further advantage of the system disclosed herein is that the linear antennas out of the first antenna system don't need to be actively tunable and that the loop antennas out of the second antenna system don't need to be actively tunable. Each antenna in the system, be it a loop antenna out of the one or more loop antennas or a