phase-contrast MRI
Specialized MRI technique that measures blood flow velocity and volume by detecting phase shifts in moving protons.
Full Definition
Phase-contrast magnetic resonance imaging (PC-MRI) is a quantitative flow measurement technique that exploits the phase shift of moving protons in a magnetic field gradient to calculate blood velocity. In cardiac imaging, PC-MRI is used to measure flow volumes across valves, assess shunt ratios, and evaluate vascular flow patterns. The technique provides both magnitude and velocity images, with velocity encoded in grayscale or color overlays. Through-plane flow measurements enable calculation of stroke volumes and cardiac output, while in-plane imaging can visualize complex flow patterns such as those seen in aortic regurgitation.
Usage
Usage note: Specify the velocity encoding (VENC) parameter and measurement plane orientation.
In Context
- "Phase-contrast MRI through the ascending aorta measured a stroke volume of 65 mL." — CMR flow study report
- "The phase-contrast sequence revealed turbulent flow in the ascending aorta consistent with aortic stenosis." — Cardiac MRI report