Method and system for MRI venography including arterial and venous discrimination

An MRI apparatus for MR venography capable of discriminating veins from arteries comprising:

• a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a bore of a magnet to impress a polarizing magnetic field and an RF transceiver system and an RF modulator controlled by a pulse control module to transmit RF signals to an RF coil assembly to acquire MR images;
• and
• a computer programmed to:
• activate the MRI system in a prescan mode to acquire an arterial signal from a patient;
• monitor a magnitude of the arterial signal during a diastolic portion of a cardiac cycle;
• set a velocity encoding value at a level higher than the monitored magnitude of the arterial signal;
• and
• activate the MRI system to acquire a phase contrast image during diastole using the velocity encoding value as a noise threshold.

A venography system to discriminate venous blood flow from arterial blood flow and display an MR image with only a representation of one of arterial blood flow and venous blood flow comprising:

• an MRI apparatus capable of producing arterial and venous signals from a monitored patient;
• a user interface to select an MR image from a group consisting of an arterial only blood flow image and a venous only blood flow image;
• a velocity encoding module connected to, and receiving the arterial and venous signals from, the MRI apparatus, and producing a VENC value that establishes a noise level in the phase image whose value is between that of the arterial signal and that of the venous signal in the phase image during a cardiac diastolic period of an MR image;
• an image reconstruction module connected to the velocity encoding module to produce a magnitude image and a phase image;
• and
• a mask module connected to receive the magnitude and phase images and produce either one of the venous blood flow image and the arterial blood flow image based on an input to the user interface.

An MR venography apparatus for displaying only one of venous blood flow and arterial blood flow comprising:

• means for acquiring an MRI;
• means for ECG-gating MRI acquisitions during a diastolic period of a cardiac cycle;
• means for encoding a velocity encoding value for suppressing arterial blood flow signals during the diastolic period MRI acquisitions;
• means for reconstructing a magnitude image and a phase map image;
• means for processing the reconstructed magnitude and phase map images to create venous only and arterial only output signals;
• and
• means for displaying one of the venous only output signal as a venous blood flow image and the arterial only output signal as an arterial blood flow image.