MR imaging method and apparatus for guiding a catheter
First Claim
1. A MR imaging method comprising:
- generating a plurality of sequences, each comprising one or more RF pulses and one or more magnetic gradient fields, which act on an examination zone to produce MR signals from which successive MR images can be constructed showing, over time, a region of a body including a moveable part;
receiving the MR signals produced;
reconstructing successive MR images from the MR signals received;
automatically successively analyzing a plurality of the reconstructed MR images to determine the position of the moveable part in each current MR image being analyzed; and
after each determination of position of the moveable part in a current MR image being analyzed, automatically adjusting a variation in time of at least one of the RF pulses and magnetic gradient fields for subsequent sequences in dependence on the determined position for producing the MR signals from which the next MR image of the successive MR images will be reconstructed.
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Abstract
The invention relates to an MR imaging method in which a plurality of sequences, each of which comprises at least one RF pulse and at least one magnetic gradient field, act on an examination zone and in which at least one MR image is reconstructed from the MR signals thus acquired, and also relates to an apparatus for carrying out this method. Optimization can be achieved by subjecting the MR image to an analysis and by adjusting the variation in time of the RF pulses and/or the magnetic gradient field for the subsequent sequences in dependence on the analysis result. In particular, for positioning an object with suitable MR contrast in a body under examination at least one MR survey image of the body is formed prior to the introduction of the object. Then, after introduction of the object into the body, MR images of a small target region around and in front of the object are continuously formed and combined with the MR survey image for display purposes. The MR images of the target area are automatically analyzed to determine the location of the target region for the next MR image.
223 Citations
16 Claims
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1. A MR imaging method comprising:
- generating a plurality of sequences, each comprising one or more RF pulses and one or more magnetic gradient fields, which act on an examination zone to produce MR signals from which successive MR images can be constructed showing, over time, a region of a body including a moveable part;
receiving the MR signals produced;
reconstructing successive MR images from the MR signals received;
automatically successively analyzing a plurality of the reconstructed MR images to determine the position of the moveable part in each current MR image being analyzed; and
after each determination of position of the moveable part in a current MR image being analyzed, automatically adjusting a variation in time of at least one of the RF pulses and magnetic gradient fields for subsequent sequences in dependence on the determined position for producing the MR signals from which the next MR image of the successive MR images will be reconstructed.
- generating a plurality of sequences, each comprising one or more RF pulses and one or more magnetic gradient fields, which act on an examination zone to produce MR signals from which successive MR images can be constructed showing, over time, a region of a body including a moveable part;
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2. A MR imaging method comprising the steps of:
- generating a plurality of sequences, each comprising one or more RF pulses and one or more magnetic gradient fields, which act on an examination zone to produce MR signals;
receiving the MR signals produced;
reconstructing an MR image from the MR signals received;
automatically analyzing the reconstructed MR image; and
adjusting a variation in time of at least one of the RF pulses and magnetic gradient fields for subsequent sequences in dependence on a result of said analyzing step, wherein said method is for acquiring successive images used for guiding positioning of an object, having a front end, introduced into a human or animal body, wherein said steps of generating sequences, receiving MR signals and reconstructing an MR image are for acquiring at least one MR survey image before introduction of the object into the body, and, after introduction of the object into the body, successively acquiring MR images of a target region around and in front of the object, which successively acquired MR images of the target region are small in comparison with the MR survey image, and further comprising the step of combining the successively acquired MR images of the target region with the MR survey image, and wherein said step of analyzing the reconstructed MR image is for determining the position of the front end of the object in the successively acquired MR images of the target region, and, on the basis of such determination of the position of the front end of the object, determining the position of the target region for a next one of the successive MR images of the target region to be acquired, and wherein the step of adjusting a variation in time of at least one of the RF pulses and magnetic gradient fields is in dependence on the determination of position of the target region for the next MR image of the target region to be acquired. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
- generating a plurality of sequences, each comprising one or more RF pulses and one or more magnetic gradient fields, which act on an examination zone to produce MR signals;
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11. A MR apparatus comprising:
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a) a magnet system for generating a steady uniform magnetic field in an examination zone, b) a gradient coil system for generating magnetic gradient fields in the examination zone, c) an RF coil system for generating an RF magnetic field and for receiving MR signals from the examination zone, d) reconstruction means for reconstructing a MR image from the received MR signals, e) analysis means for analyzing a MR image reconstructed by the reconstruction means to automatically determine the position of a moveable part in the MR image, f) control means for controlling the gradient coil system and the RF coil system for producing a variation in time of currents in the gradient coil system and in the RF coil system and for controlling the reconstruction means and the analysis means in order to acquire and automatically determine the position of the moveable part in successive MR images of a region of a body in the examination zone, wherein after each determination of position of the moveable part in a current MR image of the successive MR images the variation in time of at least one of said currents is automatically adjusted in dependence on the determined position for producing the MR signals from which the next MR image of the successive MR images will be reconstructed, and g) means for displaying the acquired successive MR images.
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12. An MR apparatus, comprising:
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a) a coil system for generating a steady uniform magnetic field in an examination zone, b) a gradient coil system for generating magnetic gradient fields in the examination zone, c) an RF coil system for generating an RF magnetic field and for receiving MR signals from the examination zone, d) reconstruction means for reconstructing an image from the received MR signals, e) analysis means for analyzing an MR image reconstructed by the reconstruction means, f) control means for controlling the gradient coil system and the RF coil system for producing a variation in time of currents in the gradient coil system and in the RF coil system and for controlling the reconstruction means in order to acquire successive MR images of a region of a body in the examination zone, wherein for acquiring subsequent MR images the variation in time of at least one of said currents is adjusted in dependence on a result of analysis by the analysis means, and g) means for displaying the successively acquired MR images, wherein said control means controls said gradient coil system, said RF coil system and said reconstruction means for acquiring a MR survey image of the region of the body in the examination zone and for acquiring MR images of a target region which is small in comparison with the MR survey image, and wherein said analysis means comprises an image processing unit for detecting the position of a front end of an object with a suitable MR contrast in the MR images of the target region, and for defining the target region for a next MR image in dependence on the detected position and wherein said reconstruction means is configured for continuously mapping the successive MR images of the target region in the MR survey image.
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13. A MR imaging method comprising:
- generating a plurality of sequences, each comprising one or more RF pulses and one or more magnetic gradient fields, which act on an examination zone to produce MR signals from which successive MR images can be constructed showing, over time, a region of a body;
receiving the MR signals produced;
reconstructing successive MR images from the MR signals received;
automatically successively analyzing a plurality of the reconstructed MR images to determine a parameter in each current MR image being analyzed; and
after each determination of the parameter, automatically adjusting a variation in time of at least one of the RF pulses and magnetic gradient fields for subsequent sequences in dependence on the determined parameter for producing the MR signals from which the next MR image of the successive MR images will be reconstructed. - View Dependent Claims (14)
- generating a plurality of sequences, each comprising one or more RF pulses and one or more magnetic gradient fields, which act on an examination zone to produce MR signals from which successive MR images can be constructed showing, over time, a region of a body;
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15. A MR apparatus comprising:
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a) a magnet system for generating a steady uniform magnetic field in an examination zone, b) a gradient coil system for generating magnetic gradient fields in the examination zone, c) an RF coil system for generating an RF magnetic field and for receiving MR signals from the examination zone, d) reconstruction means for reconstructing a MR image from the received MR signals, e) analysis means for analyzing a MR image reconstructed by the reconstruction means to automatically determine a parameter in the MR image, f) control means for controlling the gradient coil system and the RF coil system for producing a variation in time of currents in the gradient coil system and in the RF coil system and for controlling the reconstruction means and the analysis means in order to acquire and automatically determine the parameter in successive MR images of a region of a body in the examination zone, wherein after each determination of the parameter in a current MR image of the successive MR images the variation in time of at least one of said currents is automatically adjusted in dependence on the determined parameter for producing the MR signals from which the next MR image of the successive MR images will be reconstructed, and g) means for displaying the acquired successive MR images. - View Dependent Claims (16)
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Specification