Rapid measurement of time-averaged blood flow using ungated spiral phase-contrast MRI
AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorsJong B. Park, Dwight G. Nishimura
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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.
Claims18
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 information.
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