Non-contrast MRI signal acquisition

Apparatus for acquiring a plurality of MR-images at respectively corresponding times related to a subject's cardiac cycle, said apparatus comprising an MRI system having at least one programmed computer configured to include:

• means for acquiring a first plurality of MR signals from a patient's tissue at respectively corresponding successive first time increments extending over a first time interval including a substantial majority of a subject's cardiac cycle;
• means for analyzing data representing magnitudes of the acquired first plurality of MR signals to define a second time interval, shorter than said first time interval, during the cardiac cycle whereat there is a relatively steep rise in signal magnitudes as a function of time corresponding with systole and diastole events of the cardiac cycle;
• means for acquiring a second plurality of MR signals from tissue of said patient at respectively corresponding successive second time increments during said second time interval, said second time increments being substantially shorter than said first time increments;
• means for generating image data representing at least one contrast-free image of flowing fluid vessels based on said second plurality of MR signals respectively acquired at different times during said second time interval;
• and
• means for outputting said generated image data to at least one of:
• (a) a display, (b) a non-transitory data storage medium, and (c) a remote device.