Breast coil arrangement for magnetic resonance applications

A breast coil arrangement for magnetic resonance applications has a placement web that allows an examination subject to lie with her sternum on the placement web with each breast in a receptacle respectively on opposite sides of the placement web. The breast receptacles have limiting elements whose spacing from one another can be adjusted. Multiple array coils are respectively arranged in the limiting elements and are stationary relative to the limiting elements. Each breast receptacle is surrounded by a volume coil that is stationary relative to the placement web. The volume coils are arranged centrally and orthogonally relative to the array coils and surround the array coils. The volume coils are decoupled from the array coils. A spectroscopy phantom can be arranged in proximity to the placement web.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns a breast coil arrangement for magnetic resonance applications, of the type having a placement web that is designed so that an examination subject lays with her sternum on the placement web, and a pot-like breast receptacle for each breast of the examination subject on both sides of the placement web.

2. Description of the Prior Art

Breast coil arrangements of the above general type are known in varying designs. For example, a breast coil arrangement of the aforementioned type is known in which every breast receptacle possesses an inner limiting element facing toward the placement web and an outer limiting element facing away from the placement web. The distances of the inner and outer limiting elements from one another can be set so that the size of the respective breast receptacle can be adapted to the size of the breasts of the examination subject. In each of the inner and outer limiting elements, respective multiple array coils are arranged to each detect a magnetic resonance signal, such that the array coils are arranged stationary relative to the respective limiting elements.

Furthermore, a breast coil arrangement of the aforementioned type is known which corresponds in terms of approach to the embodiment that was just described. However, instead of the array coils, each breast receptacle is surrounded by a respective volume coil arranged stationary relative to the placement web.

In both known breast coil arrangements, the inner limiting elements are arranged stationary relative to the placement web. The outer limiting elements are movable.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved breast coil arrangement for magnetic resonance applications.

This object is achieved in accordance with the invention by a breast coil arrangement for magnetic resonance applications having a placement web that is designed to allow an examination subject to lie with her sternum on the placement web. Pot-like breast receptacles for each breast of the examination subject are respectively arranged on opposite sides of the placement web. The breast receptacles have limiting elements whose spacing from one another can be adjusted. Multiple array coils are respectively arranged in the limiting elements and are stationary relative to the limiting elements. Each breast receptacle is surrounded by a volume coil that is stationary relative to the placement web. The volume coils are arranged centrally and orthogonally relative to the array coils and surround them. The volume coils are decoupled from the array coils. A spectroscopy phantom can be arranged in proximity to the placement web. The breast receptacles as a structural unit can be detached individually or together from the placement web, and volume-reducing inserts can be inserted into the breast receptacles. Lateral supplementary placement elements carrying axilla coils can be provided and may be separately deactivated depending on an input option of a user.

The invention is based on the two known embodiments described in the preceding are combined with one another. Both the array coils and the volume coils are thus present. The volume coils are hereby arranged centrally and orthogonally relative to the array coils respectively surrounded by them such that—due to the geometric arrangement of the volume coils and the array coils that they respectively surround—the volume coils are decoupled from the array coils that they respectively surround, independent of the adjustment of the respective breast receptacle.

A good signal-to-noise ratio (SNR) results with little effort due to the embodiment according to the invention. In particular, a greater fill factor of the array coils always results due to the ability to place the array coils on the breasts of the examination subject.

In a preferred embodiment, the inner and the outer limiting elements of each breast receptacle adjoin one another at transition regions independent of the setting of the respective breast receptacle and hereby always form obtuse angles with one another at the transition regions. This embodiment allows the breasts of the examination subject are displaced upon adjustment of the breast receptacles but are not pinched.

In an embodiment, the breast coil arrangement has a placement web that is designed so that an examination subject lies with her sternum on the placement web. The breast coil possesses a respective pot-like breast receptacle for each breast of the examination subject on both sides of the placement web. Multiple coils serving for the acquisition of magnetic resonance signals are respectively associated with each breast receptacle. For example, the associated coils can be the array coils and/or the volume coils of the aforementioned embodiment. The remainder of the aforementioned features can also be realized, but this is not absolutely necessary.

Independently of whether the remaining features of the first explained embodiment are realized or not, the breast receptacles are arranged symmetrically relative to the receptacle web. Each breast receptacle has an upper and a lower opening as viewed in the direction of a longitudinal extent of the placement web. An upper connection line connecting the two upper openings with one another and a lower connection line connecting the two lower openings with one another run parallel to one another and orthogonal to the longitudinal extent of the placement web. A spectroscopy phantom is arranged in the region of one of the connection lines and in proximity to the placement web. It is hereby preferable that the spectroscopy phantom is arranged outside of a middle region bounding the two connection lines.

These embodiments allow the spectroscopy phantom to remain in the breast coil arrangement. It does not interfere with the normal operation of the breast coil arrangement. Nevertheless, a spectroscopy and the calibration of the magnetic resonance signal that is connected with this are possible.

In a further embodiment, the breast coil arrangement has a placement web that is designed so that an examination subject lies with her sternum on the placement web. The breast coil has a respective pot-like breast receptacle for each breast of the examination subject on both sides of the placement web. Multiple coils serving to acquire magnetic resonance signals are respectively associated with each breast receptacle. Additional features explained in the preceding in connection with the present invention can also be realized, but this is not absolutely necessary.

According to the invention, the breast receptacles (including the coils associated with them) can as a structural unit be detached individually or together from the placement web without tools. A biopsy coil arrangement as a structural unit can be connected with the placement web without tools as a replacement for the breast receptacles. The biopsy coil arrangement hereby respectively possesses at least one volume coil arranged stationary relative to the placement web for each breast of the examination subject. The breast coil arrangement can be universally used via this embodiment.

The breast coil arrangement in a further embodiment also possesses a placement web that is designed to allow an examination subject to lie with her sternum on the placement web. The breast coil also has respective pot-like breast receptacles for each breast of the examination subject on both sides of the placement web. The additional features of one or more of the preceding embodiments according to the invention can also be realized. Inserts that are stably held in the breast receptacles are inserted into the breast receptacles. Each insert has a curved insert recess on a side facing toward the examination subject, so that the breasts of the examination subject are stably held in the respective insert recesses although the breast receptacles are larger than the breasts of the examination subject. Movement-dependent artifacts can be minimized via this embodiment.

In a preferred embodiment, the inserts respectively border the insert recesses on their sides facing toward the placement web with a respective inner limiting web and respectively border the insert recesses on their sides facing away from the placement web with a respective outer limiting web. For each of the insert recesses, the respective inner limiting web and the respective outer limiting web have differing web thicknesses. This allows the location of the insert recesses to be adapted to the separation between the breasts of the particular examination subject.

Alternatively or additionally each insert my have a curved insert recess on the side facing away from the examination subject so the same inserts (depending on how they are inserted into the breast receptacles) can be used for two breast sizes differing from one another.

The inserts advantageously are formed of a soft material that forms a smooth curve in its region adjoining the breasts of the examination subject. A relatively comfortable body contact with the inserts thereby results for the examination subject.

The above object also is achieved by a breast coil arrangement in accordance with the invention having a placement web that is designed so that an examination subject lies with her sternum on the placement web. The breast coil also has a respective pot-like breast receptacle for each breast of the examination subject on both sides of the placement web. Multiple coils that serve for the acquisition of magnetic resonance signals originating from the region of the respective breast receptacle are respectively associated with each breast receptacle. The breast coil arrangement can be a breast coil arrangement according to any of the embodiments of the present invention that are explained in the preceding. The breast coil arrangement furthermore has supplemental placement elements that, together with the placement web, respectively bifurcate one of the breast receptacles. Axilla coils that serve for the acquisition of magnetic resonance signals originating from the axilla region of the examination subject are integrated into the supplemental placement elements.

The breast coil arrangement according to the invention is used in magnetic resonance systems. In a breast coil arrangement of the type just described it is possible for the coils serving for the acquisition of magnetic resonance signals originating from the region of the respective breast receptacle to be alternatively operated together with the axilla coils, or without the axilla coils, depending on an input option made by a user of the magnetic resonance system. The “normal” coils are thus always operated, but whether the axilla coils are also operated can be chosen by the user.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown inFIG. 1, a magnetic resonance system has a scanner (data acquisition unit)1, a patient bed2and a control device3. The scanner1typically has a basic field magnet system4, a gradient magnet system5and a whole-body coil6. The basic magnet system4, the gradient magnet system5and the whole-body coil6are arranged around a patient tunnel7. A static, homogeneous basic magnet field is generated in the patient tunnel7by the basic field magnet system4. A gradient field is generated in the patient tunnel7by means of the gradient magnet system5. An examination subject8(insofar as she is located in the patient tunnel7) can be excited to emit magnetic resonance signals by RF radiation from the whole-body coil6. The gradient magnet system5and the whole-body coil6are controlled for this purpose by the control device3.

The examination subject8can be driven through the patient tunnel7by means of the patient bed2. Appropriate control of the patient bed2by the control device3ensues for this purpose. An examination subject8would lie with her back on the patient bed2, but within the scope of the present invention the examination subject8(in all cases a woman within the scope of the present invention) lies ventrally on a breast coil arrangement9. The face10of the examination subject8thus faces toward the patient bed2. The breast coil arrangement9contains multiple local coils for localized RF transmission/reception. The local coils are not shown inFIG. 1. The local coils are connected with the control device3via a shielded multi-core cable11.

Breast coil arrangements9for magnetic resonance applications are generally known. The described embodiments of the breast coil arrangement9and its use are the subject matter of the present invention. The present invention is hereby explained in detail in connection withFIGS. 2 through 13.

As shown inFIG. 2, the breast coil arrangement9has a placement web12. The placement web12is designed so that the examination subject8lies with her sternum on the placement web12. The face10of the examination subject8is located in the region of a central opening13of the breast coil arrangement9. Depending on the size of the examination subject8, the lower ribs of the examination subject8are located approximately in the region of the end14of the breast coil arrangement9that is at a distance from the central opening13.

On each side of the placement web12, the breast coil arrangement9has one pot-like breast receptacle15, for each breast16(seeFIG. 1) of the examination subject8. Each breast receptacle15has an inner limiting element17and an outer limiting element18(seeFIGS. 3 and 4). The L-shape of each inner limiting element17faces away from the placement web12. The L-shape of each outer limiting element18faces toward the placement web12.

The separation (spacing) between each pair of inner and outer limiting elements17,18is adjustable. This is indicated by arrows A inFIGS. 3 and 4. The size of the respective breast receptacle15thus can be adapted to the size of the breasts16of the examination subject8.

According to a preferred embodiment, the inner limiting elements17are stationary relative to the placement web12. Only the outer limiting elements18are movable. Other embodiments are possible, such as both the inner and the outer limiting elements17,18being adjustable.

According toFIGS. 3 and 4, multiple array coils19are respectively arranged in each of the inner and outer limiting elements17,18. The array coils19serve to acquire a magnetic resonance signal. The array coils19are hereby arranged stationary relative to the respective limiting element17or18. Furthermore, each breast receptacle15is surrounded by a respective volume coil20. The volume coils20are stationary relative to the placement web12. They are thus not moved given an adjustment of the inner and/or outer limiting elements17,18. As is particularly clearly visible fromFIG. 4, the volume coils20are arranged centrally and orthogonally relative to the array coils19that they respectively surround. Due to this arrangement, the volume coils20are decoupled from the array coils19that they respectively surround. Due to the geometric arrangement of the array coils19and the volume coils20, the decoupling is already provided independently of the adjustment of the respective breast receptacle15, thus independently of the distance of the inner and the outer limiting elements17,18from one another.

According to a preferred embodiment, the inner and the outer limiting elements17,18of each breast receptacle15adjoin one another at transition regions21independently of the adjustment of the respective breast receptacle15. Independently of the adjustment of the respective breast receptacle15, the respective inner and the respective outer limiting elements17,18always exhibit obtuse angles α at the transition regions21. The angles α can exhibit values differing from one another from transition region21to transition region21, but they are always greater than 90°. Generally they lie in a range from 120 to 150°.

The breast coil arrangement9ofFIG. 5also has a placement web12that is designed so that the examination subject8lies with her sternum on the placement web12. Furthermore, the breast coil arrangement9ofFIG. 5has a pot-like breast receptacle15for each breast16of the examination subject8on each side of the placement web12. Multiple coils19,20serving for the acquisition of magnetic resonance signals are respectively associated with each breast receptacle19. The breast coil arrangement9according toFIG. 5can be a breast coil arrangement9according toFIGS. 2 through 4. This embodiment is preferred, but is not necessary. Independently of whether the breast coil arrangement9ofFIG. 5has the additional features explained in the preceding in connection withFIGS. 2 through 4, the following applies:

The breast receptacles15are arranged symmetrically relative to the placement web12. Each breast receptacle15has an upper opening and a lower opening22,23as viewed in the direction of a longitudinal extent x of the placement web12. Due to this design, an upper connection line24which connects the two upper openings22with one another runs orthogonally relative to the longitudinal extent x of the placement web12. A lower connection line25which connects the two lower openings23with one another likewise runs orthogonal to the longitudinal extent x of the placement web12. Furthermore, the upper and the lower connection lines24,25proceed parallel to one another.

This embodiment can also be provided in the breast coil arrangement9ofFIGS. 2 through 4(at least in the normal case). However, in the breast coil arrangement9ofFIG. 5, a spectroscopy phantom26is arranged in the region of one of the connection lines24,25and in proximity to the placement web12(seeFIG. 6). In a preferred embodiment (shown inFIG. 6with solid lines) the spectroscopy phantom26is arranged outside of a middle region27that is bordered by the two connection lines24,25. However, additional possible positionings of the spectroscopy phantom26are also drawn with dashed lines inFIG. 6.

The breast coil arrangement9according toFIG. 7also has a placement web12that is designed so that the examination subject8lies with her sternum on the placement web12. Furthermore, the breast coil arrangement9ofFIG. 7likewise has a pot-like breast receptacle15for a breast16of the examination subject8on each side of the placement web12. Again, multiple coils19,20serving for the acquisition of magnetic resonance signals are respectively associated with each breast receptacle15. to this extent the breast coil arrangement9ofFIG. 7corresponds with the breast coil arrangement9described in the preceding in connection withFIGS. 2 through 4andFIG. 5. The additional features corresponding to the embodiment ofFIGS. 2 through 4and/or corresponding to the embodiment according toFIGS. 5 and 6can also be present. This is preferred, but is not necessary.

Independently of whether these additional features are present or not, the breast receptacles15are detachable as a structural unit (including the coils19,20associated with them) from the placement web12. This is indicated by arrows B inFIG. 7. The breast receptacles15thus can be detached from the placement web12without tools. It can be possible to detach the two breast receptacles15from the placement web12individually. It is also possible for the two breast receptacles15to form a common structural unit.

According toFIG. 8, a biopsy coil arrangement28can be connected with the placement web12as a replacement for the breast receptacles15(likewise as a structural unit and likewise without tools). For example, the preferred embodiment12can possess corresponding retention elements29, for example in the form of hook and loop fasteners (Velcro® tape). The biopsy coil arrangement28has at least one volume coil30for each breast16of the examination subject8, for example two volume coils30per breast16.

The volume coils30are arranged stationary relative to the placement web12. The breasts16of the examination subject8are freely accessible to the sides from the outside given use of the biopsy coil arrangement28, in particular for biopsy purposes.

If the breast coil arrangement9ofFIG. 7is fashioned corresponding toFIGS. 2 through 4, the structural unit includes the breast receptacles15, the limiting elements17,18and the array coils19as well as the volume coil20. If the breast coil arrangement9ofFIG. 7is fashioned corresponding to the embodiment ofFIGS. 5 and 6, the structural unit advantageously also include the spectroscopy phantom26. In the individual case, however, the spectroscopy phantom26can remain in the breast coil arrangement9.

The breast coil arrangement9according toFIG. 9also has a placement web12that is designed so that the examination subject8lies with her sternum on the placement web12. The breast coil arrangement9ofFIG. 9furthermore has a pot-like breast receptacle15for each breast16of the examination subject8on each side of the placement web12. The additional features of one or more of the embodiments according toFIGS. 2 through 4,5and6as well asFIGS. 7 and 8can also be present. This is preferred, but is not necessary. Inserts31are inserted into the breast receptacles15in the breast coil arrangement9according toFIG. 9(see in particularFIGS. 10 and 11). The inserts31are held stably in the breast receptacles15. On the sides facing toward the examination subject8, each insert31has a curved insert recess32. Due to the insert recesses32, the breasts16of the examination subject8are held stably in the insert recesses32. This applies although the breast receptacles15are larger (in principle or in their current setting) than the breasts16of the examination subject8.

In a preferred embodiment, each insert31borders the insert recess32with an inner limiting web33on the side closer to the placement web12. Each insert31borders the insert recess32with an outer limiting web34on the side farther away from the placement web12. The inner limiting web33and the outer limiting web34respectively exhibit web thicknesses d, d′ that differ from one another in each of the insert recesses32. It is therefore possible to rotate the inserts31by 180° around a vertical axis35so that the respective inner and outer limiting webs33,34change the position (orientation) of the insert recess32relative to the web12. The location of the insert recesses32thus can be adapted to the separation of the breasts16of the examination subject8from one another via corresponding rotation of the inserts31around the respective vertical axes35.

As an alternative or in addition to the presence of differing web thicknesses d, d′, according toFIG. 10it is furthermore possible for each insert31to have an additional curved insert recess36on the side facing away from the examination subject8. It is therefore possible to rotate the inserts31by 180° around a horizontal axis37so that the insert recesses32and the additional insert recesses36exchange their locations. In this way same insert31can be used for two different breast sizes of different examination subjects8.

The inserts31advantageously are formed of a soft material (for example a foamed material) so that they are elastically deformable. The material advantageously forms a smooth curve in its region adjoining the breasts16of the examination subject8. A relatively comfortable body contact thereby results for the examination subject8. In the case of a foamed material, the foamed material is advantageously water-repellent.

The size of the insert recesses32and of the additional insert recesses36can be selected as needed. A volume ratio of the insert recesses32and the additional insert recesses36normally is in the range of approximately 2:1.

In the breast coil arrangement9according toFIG. 12, the breast coil arrangement9also has a placement web12that is designed so that the examination subject8lies with her sternum on the placement web12. Furthermore, in the breast coil arrangement according toFIG. 12a pot-like breast receptacle15is present for each breast16of the examination subject8. Furthermore, multiple coils19,20that serve to acquire magnetic resonance signals originating from the region of the respective breast receptacle15are also respectively associated with each breast receptacle15in the breast coil arrangement9according toFIG. 12.

The breast coil arrangement fromFIG. 12can be a breast coil arrangement9according to one or more of the embodiments explained in the preceding, thus according toFIGS. 2 through 4and/orFIGS. 5 and 6and/orFIGS. 7 and 8and/orFIGS. 9 through 11, but this is not necessary.

As shown inFIGS. 12 and 13, the breast coil arrangement9has supplementary placement elements38. The supplementary placement elements38together with the placement web12respectively bifurcate one of the breast receptacles15. Axilla coils39are integrated into the supplementary placement elements38. The axilla coils39serve for the acquisition of magnetic resonance signals that originate from the axilla region of the examination subject8.

If the breast coil arrangement9according toFIGS. 12 and 13is fashioned corresponding toFIGS. 2 through 4, the supplementary placement elements38are connected with the outer limiting elements18. If the breast coil arrangement9is fashioned corresponding toFIGS. 7 and 8, the supplementary placement elements38(and the axilla coils39) are a component of the removable structural unit.

It is possible to always operate the axilla coils39together with the additional coils19,20(thus for example the array coils19and the volume coils20). However, it is advantageously possible for a user40of the magnetic resonance system to decide whether to provide a control command C to the control device3or not. The control command C represents an input option to the user40. If the user40provides the control command C, the axilla coils39are operated. If the user40does not provide the control command C, the axilla coils39are not operated. In both cases, however, the remaining coils19,20are operated. The selection of the corresponding operating state—operation of the axilla coils39or no operation of the axilla coils39—can be implemented by the control device3, for example by the control device3detuning or not detuning the axilla coils39by a corresponding control signal D. The other coils19,20can be operated with a greater sampling at the same resulting spatial resolution due to the deactivation of the axilla coils39.