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Comparison of in-vivo arteriovenous fistula volume flow measurements using a Transonic transit time ultrasound flow device and Doppler ultrasound  

Schroedter WB, Burke SK, Medenhall V  

Introduction:   Doppler ultrasound (US) is extensively validated for classification of vascular disease based on velocity calculations.  While widely used to evaluate dialysis access arteriovenous fistulas (AVF), accurate volume flow measurements have proved more elusive with significant variability resulting in large thresholds for differentiation of normally functioning from failing fistula.  We sought to compare in-vivo measurements of AVF blood flow volume measured by the Transonic transit-time ultrasound flow device with those of Doppler US.    

Methods:   Bilateral femoral AVFs (n=6) were created in swine (n=3).  Comparative volume flow measurements were made at baseline, 15, 30, 60, and 120 minutes post-AVF creation with the Transonic device and with Doppler US using an estimated time averaged velocity and the diameter of the vessel to calculate volume flow using the formula: Q= v A = v  , where Q=volume flow, v= time and spatial averaged mean velocity, A = cross sectional area, and r=radius of the vessel. Repeat measurements (minimum 3) were performed at each time point.  Linear and multiple linear regression analyses were performed.

Results:   Linear regression analyses showed a weak correlation (R2=0.103, p=0.002) between Transonic and Doppler volume flow measurements.  Doppler consistently showed higher volume flow over all time points than Transonic data.  Average Transonic values had less variability over time (R2 = 0.9505) as compared to average Doppler measurements (R2 = 0.7601).  Average flow increased over time, regardless of the flow measurement device consistent with reported clinical observation of AVF maturation process.  Multiple linear regression analysis demonstrated correlation between Doppler and Transonic data (R2=0.197, p=0.013), and provided a formula to estimate Transonic flow measurement from the Doppler data.  {{ Transonic = 113.742 + (0.334 * Doppler) }}. 

Conclusions: Transonic data demonstrated a stronger relationship between volume flow and time than Doppler data, suggesting transit time ultrasound volume flow measurements may be more accurate.  Doppler data tended to overestimate volume flow measurements however it may be feasible to use a correction factor for Doppler data that predicts Transonic results.  


Current Happenings 

Introducing our new educational website.

Virtual Vein Center is a new concept in educational delivery. Get the education you need and want, when you need it. If you need CME, you can get them here as well.

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 Several QVI staff took time to attend the 2014 American College of Phlebology Annual Congress in Phoenix Arizona in November to deliver numerous  workshops and lectures. It was a high quality meeting as usual. The complete program is available for download here. 


The 2014 SVU Annual Conference was held in Orlando and several QVI attended and presented numerous presentations. Jeannie was also honored as a Fellow of the SVU.  

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Jeannie recently attended the 25th Society of Vascular Medicine 2014 Annual Conference as an invited speaker in La Jolla, Ca. Her numerous lectures were very well received.

 The International Union of Phlebology, in conjunction with the American College of Phlebology held its World Meeting in Boston in September 2013. Held only every 4 years, this was the first time ever in the US. Several QVI staff were invited speakers  presenting some original scientific research.  

QVI News

Sydney, Australia

Bill was the International Keynote Speaker at the Australian Sonographer Association Annual National Conference in Sydney.

What a great experience!  

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QVI was once again awarded the D.E. Strandness Award for Scientific Excellence at the 2013 SVU Annual Conference.

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Medical Compression socks continue to be on the forefront of venous treatment. Recently, they have entered the realm of the athlete. To learn more about what compression socks can do you you, please visit


QVI wins the D.E Strandness Award at the 2012 SVU Annual Conference!

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