[Flow quantification in coronary and bypass vessels with MR phase contrast technique]

Area of Science:

• Cardiovascular imaging
• Magnetic Resonance Imaging (MRI)
• Hemodynamics

Context:

• Accurate blood flow quantification is crucial for diagnosing coronary artery disease and evaluating bypass graft function.
• Traditional methods like ultrasound have limitations in non-invasive coronary flow assessment.
• Velocity-encoded cine MRI offers a promising non-invasive approach for detailed hemodynamic analysis.

Purpose:

• To assess the accuracy of velocity-encoded cine MRI in determining blood flow within coronary arteries and coronary artery bypass grafts.
• To compare MR-derived flow measurements with intraoperative transit-time ultrasound data.
• To evaluate the feasibility of using MRI for quantifying coronary blood flow in stenosed vessels.

Summary:

• Velocity-encoded cine MRI demonstrated a significant correlation (r=0.74, p<0.0001) with transit-time ultrasound for flow quantification in bypass grafts.
• MR imaging systematically measured higher flow volumes compared to ultrasound.
• Reduced mean flow was observed in severely stenosed coronary arteries (>70%) compared to normal vessels.
• Intra- and interobserver variability for MR flow measurements were within acceptable ranges (10.5-15.8%).

Impact:

• Velocity-encoded cine MRI is a viable tool for non-invasive blood flow determination in coronary arteries and bypass grafts.
• This technique can aid in the clinical assessment of coronary artery disease severity and graft performance.
• Further advancements in spatial and temporal resolution of MRI may enhance its diagnostic capabilities.