公开(公告)号：EP1639381A2

公开(公告)日：2006-03-29

申请号：EP04737090.3

申请日：2004-06-21

申请人： Koninklijke Philips Electronics, N.V.

发明人： KLEIHORST, Robert, P. ,  WARNTJES, Jan, B., M.

IPC分类号： G01R33/341

CPC分类号： G01R33/3642 ,  G01R33/341

摘要： The invention relates to a radio-frequent (RF) coil system (17, 17’) for use in a magnetic resonance imaging (MRI) system. The RF coil system comprises at least one main coil (35) for transmitting an RF magnetic field (B1) into and/or receiving an RF magnetic field (B1’) from an examination volume (3) of the MRI system. The main coil has a main coil axis (37), which is or is to be oriented parallel to a main magnetic field (B0) in the examination volume, and at least one electrical conductor (39, 41) which extends mainly parallel to the main coil axis. According to the invention, the RF coil system comprises at least two electrical auxiliary coils (51, 53, 55, 57) which are assigned to said conductor of the main coil. The auxiliary coils are arranged on opposite sides of said conductor of the main coil. Each auxiliary coil has a coil axis (59, 61, 63, 65) which extends substantially parallel to the main coil axis at a distance from the conductor of the main coil to which the respective auxiliary coil is assigned, said distance being small relative to a main dimension (L) of the main coil. The auxiliary coils constitute passive electrical coils in which electrical currents are generated under the influence of an RF magnetic field (B11, B11’) present at the location of the auxiliary coils. The RF magnetic field (B12, B34) generated by the auxiliary coils as a result of said currents in the auxiliary coils suppresses said RF magnetic field present at the location of the auxiliary coils. Thus, the auxiliary coils provide a sensitivity reducing effect of the RF coil system in local regions (47, 49) which are at relatively small distances from the conductor of the main coil. For regions at a distance from the conductor of the main coil comparable to the main dimension of the main coil, said sensitivity reducing effect is negligible.

公开(公告)号：EP1625414A1

公开(公告)日：2006-02-15

申请号：EP04731246.7

申请日：2004-05-05

申请人： Koninklijke Philips Electronics N.V.

发明人： WARNTJES, Jan, B., M.

IPC分类号： G01R33/341

CPC分类号： G01R33/341

摘要： The invention relates to a radio-frequent (RF) coil system (17, 17') for use in a magnetic resonance imaging (MRI) system. The RF coil system comprises at least one main coil (35) for transmitting an RF magnetic field (B1) into and/or receiving an RF magnetic field (B1') from an examination volume (3) of the MRI system. The main coil has a coil axis(36), which is or is to be oriented parallel to a main magnetic field (Bo) in the examination volume (3), and at least one electrical conductor (37, 39) which extends mainly parallel to the coil axis. According to the invention, the RF coil system comprises an auxiliary coil (45, 47) which is assigned to said conductor of the main coil. The auxiliary coil has two electrical conductors (49, 51) which extend mainly parallel to the coil axis and on opposite sides of said conductor of the main coil. A distance between the two conductors of the auxiliary coil and the conductor of the main coil is small relative to a main dimension (L) of the main coil.In transmission mode, RF signals are supplied to the main coil and to the auxiliary coil with such a mutual phase difference, that a combined RF magnetic field (Bc) of 15 the main coil and the auxiliary coil has a direction of rotation (RB) opposite to a direction of precession (Rp) of the spin axes of the spinning nuclei in a body to be examined. In receiving mode, a first RF signal received by the main coil and a second RF signal received by the auxiliary coil are combined and added at such a mutual phase difference, that the second RF signal suppresses the first RF signal. In this manner, the disadvantageous high local 20 sensitivity of the RF coil system for the local region (38, 40) adjoining said conductor of the main coil is strongly reduced.

公开(公告)号：EP1728089A1

公开(公告)日：2006-12-06

申请号：EP05708892.4

申请日：2005-03-01

申请人： Koninklijke Philips Electronics N.V.

发明人： WARNTJES, Jan, B., M.

IPC分类号： G01R33/54

CPC分类号： G01R33/54 ,  G01R33/543 ,  G01R33/546 ,  G01R33/5611

摘要： The invention relates to a method and apparatus for generating magnetic resonance images. In order to achieve high quality magnetic resonance imaging combined with a user-friendly operating of a magnetic resonance apparatus it is proposed to use data obtained from a reference scan comprising SENCE reference data to determine an optimum scan parameter set taking into account a chosen target value of a specific scan parameter such as the scan time or the signal-to-noise ratio. Based on the reference scan, image noise is predicted for various sets of scan parameters (atternative use of SENCE or intrinsic foldover without SENCE; various orientations of the phase encoding direction within the slice plane). An optimun scan parameter set is determined (shortest scan time to match target SNR or hightest SNR to match target scan time).

公开(公告)号：EP1774355A1

公开(公告)日：2007-04-18

申请号：EP05760041.3

申请日：2005-07-12

申请人： Koninklijke Philips Electronics N.V.

发明人： POSSANZINI, Cecilia ,  VAN HELVOORT, Marinus, J., A., M. ,  WARNTJES, Jan, B., M. ,  KLEIHORST, Robert, P.

IPC分类号： G01R33/341

CPC分类号： G01R33/341

摘要： The invention relates to a magnetic-resonance imaging (MRI) apparatus comprising an electric coil system (17) for transmitting and receiving a radio-frequency (RF) magnetic field from an examination volume (3) of the MRI apparatus. The electric coil system (17) comprises at least one surface coil (35) which extends substantially in a plane. The surface coil is used for transmitting and/or receiving a RF magnetic field which is oriented substantially perpendicularly to the plane of the surface coil (35). The surface coil (35) has a main coil axis (37). When the MRI apparatus is in use, the main coil axis (37) extends substantially parallel to a main magnetic field in the examination volume (3) of the MRI apparatus. On both sides of the main coil axis (37), the surface coil (35) comprises an electrically conducting element (39) which extends substantially parallel to the main coil axis (37). To provide a surface coil (35) which transmits more homogeneous RF magnetic fields and/or has a more homogeneous sensitivity for received RF magnetic fields than known surface coils, at least one of the electrically conducting elements (39) of the surface coil (35) comprises at least two electric conductors (41). With respect to their distance to the main coil axis (37), these electric conductors (41) are positioned at a relatively short distance from each other. In the plane of the surface coil (35), the electric conductors (41) extend substantially parallel to the main coil axis (37) of the surface coil (35).

公开(公告)号：EP1567881A1

公开(公告)日：2005-08-31

申请号：EP03811834.5

申请日：2003-11-20

申请人： Koninklijke Philips Electronics N.V.

发明人： WARNTJES, Jan, B., M. ,  VAN DEN BRINK, Johan, S.

IPC分类号： G01R33/561 ,  G01R33/3415

CPC分类号： G01R33/5611

摘要： A novel magnetic resonance imaging method is presented for forming an image of an object from a plurality of signals acquired by an array of multiple receiver antennae. Prior to imaging a sensitivity map of each of the receiver antennae is provided, at least two adjacent antennae record signals originating from the same imaging position and the image intensity is calculated from the signals measured by different antennae, wherein the number of phase encoding steps is reduced with respect to the full set thereof. In addition the field of view is set smaller than the object size in phase encoding direction inducing intrinsic foldover artefacts, whereas the sensitivity map of the receiver antennae and a reference image featuring intrinsic foldover artefacts are used for reconstruction of the MR image to an unfolded image.