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US 12,730,170 B2Granted
Pointwise encoding time reduction with radial acquisition (PETRA) techniques with reduced computational complexity
AssigneeSiemens Healthineers AG
InventorDavid Grodzki
Life of this patent
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Abstract
In the context of a method according to the disclosure for generating measurement data from an imaging area in a measurement volume of a magnetic resonance system, using a PETRA method, a pulse duration of at least one RF excitation pulse radiated during a single-shot recording method of the PETRA method is extended compared to a pulse duration of RF excitation pulses radiated during a radial recording method of the PETRA method, whereby computing operations for correcting disruptive aliasing may be simplified.
Claims11
A method for generating measurement data from an imaging area of an examination object located in a measurement volume of a magnetic resonance system, comprising:
- reading out a k-space corresponding to the imaging area by:
- a) starting up, via a gradient field generator of a magnetic resonance system, a first gradient to a first strength in an encoding direction;
- b) radiating, via a radiofrequency (RF) transmit/receive controller of the magnetic resonance system, a first RF excitation pulse while the first gradient is at the first strength;
- c) recording, via the RF transmit/receive controller, first echo signals generated by the first RF excitation pulse after a switching time following radiation of a first RF excitation pulse;
- and
- d) storing the recorded first echo signals as first measurement data along a k-space trajectory based upon the first strength of the first gradient and the encoding direction;
- wherein steps a) to d) are repeated with constant first gradients switched in different encoding directions until the k-space corresponding to the imaging area is read out from a first area based upon the switching time,
- wherein the different encoding directions are composed of at least two phase encoding directions;
- reading out a second area of the k-space corresponding to the imaging area,
- wherein the second area at least partially is not masked by the first area of the k-space and comprises at least the k-space center, with a single-shot recording method with which, after repeated radiation respectively of each one of second RF excitation pulses, second echo signals are recorded with switching of second gradients for encoding a respective k-space position of the second area and stored as second measurement data until a predetermined number of k-space positions of the second area have been recorded;
- and
- reconstructing image data from the recorded first measurement data and the recorded second measurement data;
- wherein a pulse duration of at least one of the second RF excitation pulses is extended compared with a pulse duration of first RF excitation pulses for a recording of second echo signals of at least one k-space position in the second area, and
- wherein a pulse duration of an extended second RF excitation pulse is determined as a function of the switching time.
11 more elements
A magnetic resonance system configured to generate measurement data from an imaging area of an examination object located in a measurement volume, comprising:
- a main magnet unit;
- a gradient generator;
- a controller configured to cause:
- reading out a k-space corresponding to the imaging area by:
- a) starting up, via a gradient field generator of a magnetic resonance system, a first gradient to a first strength in an encoding direction;
- b) radiating, via a radiofrequency (RF) transmit/receive controller of the magnetic resonance system, a first RF excitation pulse while the first gradient is at the first strength;
- c) recording, via the RF transmit/receive controller, first echo signals generated by the first RF excitation pulse after a switching time following radiation of a first RF excitation pulse;
- and
- d) storing the recorded first echo signals as first measurement data along a k-space trajectory based upon the first strength of the first gradient and the encoding direction;
- wherein steps a) to d) are repeated with constant first gradients switched in different encoding directions until the k-space corresponding to the imaging area is read out from a first area based upon the switching time,
- wherein the different encoding directions are composed of at least two phase encoding directions;
- reading out a second area of the k-space corresponding to the imaging area,
- wherein the second area at least partially is not masked by the first area of the k-space and comprises at least the k-space center, with a single-shot recording method with which, after repeated radiation respectively of each one of second RF excitation pulses, second echo signals are recorded with switching of second gradients for encoding a respective k-space position of the second area and stored as second measurement data until a predetermined number of k-space positions of the second area have been recorded;
- and
- reconstructing image data from the recorded first measurement data and the recorded second measurement data;
- wherein a pulse duration of at least one of the second RF excitation pulses is extended compared with a pulse duration of first RF excitation pulses for a recording of second echo signals of at least one k-space position in the second area, and
- wherein a pulse duration of an extended second RF excitation pulse is determined as a function of the switching time.
14 more elements
A non-transitory computer-readable storage medium having instructions stored thereon that, when executed by a controller of a magnetic resonance system, cause the magnetic resonance system to generate measurement data from an imaging area of an examination object located in a measurement volume by:
- reading out a k-space corresponding to the imaging area by:
- a) starting up, via a gradient field generator of a magnetic resonance system, a first gradient to a first strength in an encoding direction;
- b) radiating, via a radiofrequency (RF) transmit/receive controller of the magnetic resonance system, a first RF excitation pulse while the first gradient is at the first strength;
- c) recording, via the RF transmit/receive controller, first echo signals generated by the first RF excitation pulse after a switching time following radiation of a first RF excitation pulse;
- and
- d) storing the recorded first echo signals as first measurement data along a k-space trajectory based upon the first strength of the first gradient and the encoding direction;
- wherein steps a) to d) are repeated with constant first gradients switched in different encoding directions until the k-space corresponding to the imaging area is read out from a first area based upon the switching time,
- wherein the different encoding directions are composed of at least two phase encoding directions;
- reading out a second area of the k-space corresponding to the imaging area,
- wherein the second area at least partially is not masked by the first area of the k-space and comprises at least the k-space center, with a single-shot recording method with which, after repeated radiation respectively of each one of second RF excitation pulses, second echo signals are recorded with switching of second gradients for encoding a respective k-space position of the second area and stored as second measurement data until a predetermined number of k-space positions of the second area have been recorded;
- and
- reconstructing image data from the recorded first measurement data and the recorded second measurement data;
- wherein a pulse duration of at least one of the second RF excitation pulses is extended compared with a pulse duration of first RF excitation pulses for a recording of second echo signals of at least one k-space position in the second area, and
- wherein a pulse duration of an extended second RF excitation pulse is determined as a function of the switching time.
11 more elements
Dependencies are inferred from the claim text.