Method for monitoring thermal heating during magnetic resonance imaging
First Claim
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1. A method for detecting the absorption of RF energy by a subject during the acquisition of image data using a selected pulse sequence on a magnetic resonance imaging (MRI) system, the steps comprising:
- a) acquiring a baseline thermal image of the subject using the MRI system;
b) performing the selected pulse sequence using the MRI system to expose the subject to RF energy produced by said pulse sequence;
c) acquiring a second thermal image of the subject using the MRI system; and
d) determining the temperature increase at locations in the subject using information in the baseline and second thermal images.
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Abstract
The SAR exposure of a subject undergoing an MRI examination is measured by acquiring a thermal image that indicates that temperature increase caused by the SAR exposure. This measurement may be used in a prescan process to adjust the SAR load produced by a prescribed imaging pulse sequence, and it can be used during the scan to adjust the SAR load produced by the prescribed imaging pulse sequence.
46 Citations
14 Claims
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1. A method for detecting the absorption of RF energy by a subject during the acquisition of image data using a selected pulse sequence on a magnetic resonance imaging (MRI) system, the steps comprising:
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a) acquiring a baseline thermal image of the subject using the MRI system;
b) performing the selected pulse sequence using the MRI system to expose the subject to RF energy produced by said pulse sequence;
c) acquiring a second thermal image of the subject using the MRI system; and
d) determining the temperature increase at locations in the subject using information in the baseline and second thermal images. - View Dependent Claims (2, 7, 8, 9)
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3. A method for automatically altering a pulse sequence for acquiring image data from a subject on a magnetic resonance imaging (MRI) system, the steps comprising:
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a) performing the pulse sequence using the MRI system to expose the subject to RF energy produced by said pulse sequence;
b) measuring the temperature increase produced at locations in the subject by acquiring a thermal image of the subject using the MRI system; and
c) altering the pulse sequence in response to the measured temperature increase to manage the SAR load on the subject. - View Dependent Claims (4, 5, 6)
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10. A method for operating a magnetic resonance imaging (MRI) system, the steps comprising:
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a) acquiring a baseline thermal image of a subject to be scanned with the MRI system;
b) performing a pulse sequence using the MRI system to expose the subject to RF energy produced during the scan;
c) acquiring a second thermal image of the subject using the MRI system;
d) determining the temperature increase at locations in the subject using information in the baseline and second thermal images;
e) adjusting the pulse sequence to alter the temperature increase it produces in the subject; and
f) acquiring an image of the subject using an imaging pulse sequence in the MRI system which employs the adjusted pulse sequence. - View Dependent Claims (11)
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12. A method for scanning a subject with a magnetic resonance imaging (MRI) system, the steps comprising:
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a) acquiring a baseline thermal image of the subject using the MRI system;
b) acquiring a plurality of NMR signals using an imaging pulse sequence, the NMR signals being used to produce an image of the subject;
c) acquiring a second thermal image of the subject using the MRI system;
d) determining the temperature increase at locations in the subject using information in the baseline and second thermal images;
e) repeating steps a) through d) until the image of the subject can be reconstructed from the acquired NMR signals; and
wherein the scan is altered if the temperature increase determined in step d) exceeds a predetermined amount. - View Dependent Claims (13, 14)
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Specification