Rapid measurement of time-averaged blood flow using ungated spiral phase-contrast MRI
First Claim
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1. A method of imaging pulsatile blood flow in a patient using magnetic resonance imaging without cardiac gating comprising the steps of:
- a) placing the patient in a static magnetic field, b) exciting nuclear spins in the presence of a gradient (Gz) for a slice defined by the gradient, c) applying a phase contrast flow encoding magnetic pulse following step b), d) applying magnetic read-out gradients (Gx, Gy) after step c) whereby spiral k-space type sampling is used during read-out, and e) acquiring read-out data, f) repeating steps b)-e) with rotated magnetic readout gradients and without cardiac gating over at least one cardiac cycle, and g) processing the acquired data to obtain time averaged flow rate information.
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Abstract
Pulsatile flow is measured using magnetic resonance imaging without cardiac gating using a phase-contrast excitation method to rapidly quantify blood flow and using a spiral k-space trajectory for image data read-out to mitigate deleterious effects of pulsatility. Post-processing of the read-out data provides a cumulative-average velocity plot from which a period of a cardiac cycle is obtained. Time-averaged blood flow rates can be rapidly and robustly measured and is more repeatable than conventional gated techniques.
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Citations
18 Claims
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1. A method of imaging pulsatile blood flow in a patient using magnetic resonance imaging without cardiac gating comprising the steps of:
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a) placing the patient in a static magnetic field, b) exciting nuclear spins in the presence of a gradient (Gz) for a slice defined by the gradient, c) applying a phase contrast flow encoding magnetic pulse following step b), d) applying magnetic read-out gradients (Gx, Gy) after step c) whereby spiral k-space type sampling is used during read-out, and e) acquiring read-out data, f) repeating steps b)-e) with rotated magnetic readout gradients and without cardiac gating over at least one cardiac cycle, and g) processing the acquired data to obtain time averaged flow rate information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification