The Effect of Using Write‐Zoom for Volume Flow Measurements in Haemodialysis Fistulas
Nikki Kong, Greg Curry, Stephen Thwaites, Ignatius Pereira, Sergio Uribe ArancibiaABSTRACT
Introduction
Arteriovenous fistulas (AVFs) are crucial for patients undergoing haemodialysis, yet about 25% fail to mature or experience early failure. Ultrasound is key in managing AVFs, with volume flow (Qa) serving as a predictor of maturation. Accurate Qa measurements depend on correctly assessing the brachial artery diameter, as errors can cause significant discrepancies. Write‐zoom, a sonographic feature that enhances spatial resolution by increasing pixel density in the target area, may improve measurement accuracy.
Methods
Thirty participants undergoing ultrasound surveillance of upper limb AVFs were included. For each, three measurements of diameter and Qa were recorded with and without write‐zoom. Statistical analysis was performed to compare both techniques.
Results
Measurements with write‐zoom (diameter: 6.0 ± 1.4 mm, Qa: 1318 ± 643 cc/min) and without (diameter: 6.3 ± 1.3 mm, Qa: 1418 ± 744 cc/min) differed significantly ( p < 0.0001 for diameter, p = 0.001 for Qa). Correlation between methods was high for both diameter ( R 2 = 0.9856, p < 0.0001) and Qa ( R 2 = 0.9739, p < 0.0001). The reliability was higher with write‐zoom for diameter (ICC (3−1) = 0.891, p < 0.001) and Qa (ICC (3−1) = 0.934, p < 0.001) compared to without (ICC (3−1) = 0.871, p < 0.001; ICC (3−1) = 0.846, p < 0.001).
Conclusion
Write‐zoom improves the reliability of Qa and diameter measurements, reducing the likelihood of overestimation. Incorporating write‐zoom into ultrasound protocols could enhance early detection of at‐risk AVFs and support timely clinical interventions.