Blood flow quantification in dialysis access using digital subtraction angiography: A retrospective study

Area of Science:

• Medical Imaging
• Vascular Surgery
• Nephrology

Background:

• Vascular access is critical for end-stage renal disease (ESRD) patients undergoing hemodialysis.
• Arteriovenous shunts in ESRD patients are prone to stenosis and thrombosis due to altered hemodynamics.
• Accurate measurement of access blood flow is essential for evaluating intervention success, but current methods are limited.

Purpose of the Study:

• To assess the feasibility of quantifying dialysis access blood flow using digital subtraction angiography (DSA) with a software tool.
• To identify optimal imaging and algorithmic parameters for accurate blood flow measurement.
• To guide the development of a dedicated imaging protocol for vascular access flow quantification.

Main Methods:

• Retrospective analysis of 173 DSA images to evaluate access flow.
• Assessment of four bolus transit time algorithms and a distance calculation method for flow computation.
• Application of gamma variate function to improve accuracy of bolus time-intensity curves, compared against catheter-based flow measurements.

Main Results:

• The cross-correlation algorithm with gamma variate curve fitting achieved the lowest quantification error (22 ± 1%).
• Other algorithms exhibited quantification errors exceeding 27%.
• The best-performing algorithm showed a bias of -94 mL/min and limits of agreement of [-353, 165] mL/min.

Conclusions:

• The cross-correlation algorithm combined with gamma variate curve fitting demonstrates the highest accuracy and reproducibility for image-based blood flow computation in dialysis access.
• Acquisition parameters, including injection specifics and frame rate, require optimization for improved accuracy.
• This approach holds promise for non-invasive assessment of vascular access hemodynamics.