NONCONTACT ELECTROPHYSIOLOGICAL MEASUREMENT AND IMAGING OF THE HEART
First Claim
1. A method assessing cardiac electrophysiologic activity in a patient, comprising the steps of:
- applying a first magnetic resonance pulse sequence to a heart of a subject at a point in a cardiac cycle where said heart is electrically active;
obtaining a first image of said heart at said point in said cardiac cycle where said heart is electrically active;
applying a second magnetic resonance pulse sequence to said heart of said patient at a point in said cardiac cycle where said heart is not electrically active, wherein said second magnetic resonance pulse sequence is the same as said first magnetic resonance pulse sequence;
obtaining a second image of said heart at said point in said cardiac cycle where said heart is not electrically active;
subtracting said second image from said first image to obtain a subtracted image of said heart; and
evaluating said subtracted image to ascertain said cardiac electrophysiological activity.
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Accused Products
Abstract
Method and system for noncontact electrophysiologic imaging of the heart. The methods may employ the magnetization and its relaxation-based measurements, sensitive or specifically sensitized to the properties of cardiac electrical activity, to determine the spatio-temporal distribution of cardiac electromagnetic field and cardiac electrical potentials, and to display such spatio-temporal distribution (image) for assisting in the identification of the regions with abnormal cardiac electrical activity. In one embodiment, the system uses external magnets, gradient magnetic fields and radio-frequency waves, such as those commonly used for MRI, to generate the magnetic resonance. The system synchronizes scanning to the cardiac cycle using a measure of cardiac activity (e.g., electrocardiogram, ultrasound, ballistocardiogram, arterial pressure or cardiac sounds) and examines the difference between the cardiac electromagnetic properties (magnetization and relaxation) modulated by the oscillating radio-frequency fields and/or gradient fields of different orientations and magnitudes in the presence and absence of the cardiac electrical currents.
28 Citations
19 Claims
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1. A method assessing cardiac electrophysiologic activity in a patient, comprising the steps of:
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applying a first magnetic resonance pulse sequence to a heart of a subject at a point in a cardiac cycle where said heart is electrically active; obtaining a first image of said heart at said point in said cardiac cycle where said heart is electrically active; applying a second magnetic resonance pulse sequence to said heart of said patient at a point in said cardiac cycle where said heart is not electrically active, wherein said second magnetic resonance pulse sequence is the same as said first magnetic resonance pulse sequence; obtaining a second image of said heart at said point in said cardiac cycle where said heart is not electrically active; subtracting said second image from said first image to obtain a subtracted image of said heart; and evaluating said subtracted image to ascertain said cardiac electrophysiological activity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A system adapted for cardiac electrophysiologic imaging of a heart of a patient comprising:
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a collection unit for collecting information related to magnetic properties of a heart using at least one programmable sequence of MRI-based electromagnetic events selected from the rotating-frame resonance, spin-locking, and synchronized gradient switching; an analysis unit for analyzing spatio-temporal dynamics of said information within a cardiac cycle to obtain the spatio-temporal distribution of at least one of an electromagnetic field and electrical potentials generated by the heart; and a display for displaying said spatio-temporal distribution of electrical potentials in the heart to enable direct tracking of at least one electrophysiological process selected from a path and speed of cardiac electrical activation and detection of regions of abnormal cardiac electrical activity.
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Specification