Apparatus and method for non-invasive measurement of cardiac output
First Claim
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1. A method for non-invasively measuring cardiac output of a patient, the method comprising the steps of:
- providing a magnetic resonance imaging (MRI) unit of a size which is significantly smaller than the size of a full-body MRI unit, said MRI unit comprises a pair of opposed magnet assemblies generating a magnetic field across an air gap there between, said air gap is dimensioned to receive a human arm;
placing said MRI unit at a height suitable to receive an arm of a human subject in a sitting or a supine position, and positioning said patient in a sitting or in a supine position respectively;
placing an arm of said patient in said air gap;
providing an array of RF coils around said patient'"'"'s arm, said array of RF coils is configured to pulse and detect electromagnetic signals;
pulsing said RF coils and detecting signals produced thereby at selected time intervals over one or more heartbeat cycles of said patient;
collecting data regarding the radial and the ulnar arteries in said patient'"'"'s arm;
analyzing said data to determine the flow rate of blood through said radial and ulnar arteries at said selected time intervals;
creating cross-sectional view images of said radial and ulnar arteries and determining cross-sectional areas of the radial and ulnar arteries at said selected time intervals;
calculating the volume of blood flowing through the radial and ulnar arteries per heartbeat or per time unit; and
calculating the total cardiac output of said patient by using known values of the percentage of cardiac output passing through the radial and ulnar arteries.
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Abstract
A comparatively light and compact permanent magnet arrangement for an MRI apparatus has a pair of opposed permanent magnet arrays with a shimming system to adjust the uniformity and strength of a magnetic field in a central chamber of the apparatus. The MRI apparatus is used to examine the extremities of a patient to determine cardiovascular characteristics from an analysis of the blood flow through selected arteries in the extremity. The information collected can be used to calculate such characteristics as total cardiac output, blood flow, arterial wall thickness and elasticity and the presence of plaque.
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Citations
13 Claims
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1. A method for non-invasively measuring cardiac output of a patient, the method comprising the steps of:
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providing a magnetic resonance imaging (MRI) unit of a size which is significantly smaller than the size of a full-body MRI unit, said MRI unit comprises a pair of opposed magnet assemblies generating a magnetic field across an air gap there between, said air gap is dimensioned to receive a human arm; placing said MRI unit at a height suitable to receive an arm of a human subject in a sitting or a supine position, and positioning said patient in a sitting or in a supine position respectively; placing an arm of said patient in said air gap; providing an array of RF coils around said patient'"'"'s arm, said array of RF coils is configured to pulse and detect electromagnetic signals; pulsing said RF coils and detecting signals produced thereby at selected time intervals over one or more heartbeat cycles of said patient; collecting data regarding the radial and the ulnar arteries in said patient'"'"'s arm; analyzing said data to determine the flow rate of blood through said radial and ulnar arteries at said selected time intervals; creating cross-sectional view images of said radial and ulnar arteries and determining cross-sectional areas of the radial and ulnar arteries at said selected time intervals; calculating the volume of blood flowing through the radial and ulnar arteries per heartbeat or per time unit; and calculating the total cardiac output of said patient by using known values of the percentage of cardiac output passing through the radial and ulnar arteries. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification