The time-distance recorder as a means of improving the accuracy of fetal blood flow measurements

Objective Volumetric flow measurement with Doppler ultrasound is useful in assessing blood flow as part of an evaluation of arteriovenous fistula maturity in patients undergoing hemodialysis. In this study, we assessed both accuracy and variability in volumetric flow measurements obtained using modern and commercially available ultrasound systems and an in vitro experimental setup. Methods Volumetric flow measurements using duplex ultrasound were obtained by 3 users operating 5 different systems for randomized flow in the range of 100 to 1000 mL/min. Users performed 3 consecutive measurements at a given flow rate. Data were analyzed using statistical techniques to assess measurement accuracy and variability. Results Over the span of flow rates studied, the root mean square error (RMSE) for the 5 ultrasound systems ranged from 38.8 to 79.7, 36.8 to 52.0, 73.0 to 85.3, 26.7 to 44.6, and 43.9 to 93.5 mL/min. Corresponding average RMSE values were 60.3, 42.7, 81.1, 37.2, and 64.4 mL/min, respectively. A linear regression analysis of mean interobserver measurements revealed an excellent correlation for all ultrasound systems (r2 > 99.1%). Assessment of intraobserver measurements revealed no statistically significant differences for any ultrasound system evaluated (P > .94). Comparison of interobserver measurements indicates no statistically significant differences between any of the 5 systems (P > .14). Conclusions Modern ultrasound systems are reasonably accurate in blood flow measurement in an experimental setup mimicking clinically relevant blood flow ranges in a hemodialysis fistula. Users need adequate training and experience to perform multiple measurements and use appropriate techniques to minimize errors in flow measurement.

show abstract

“…Requiring users to repeat measurements multiple times minimized error associated with any cyclic variation in vessel diameter. 26,27 …”

Section: Discussionmentioning

confidence: 99%

Accuracy of Volumetric Flow Rate Measurements

Hoyt

Hester

Bell

et al. 2009

Journal of Ultrasound in Medicine

View full text Add to dashboard Cite

show abstract

“…A 'frozen' picture of the vessel is obtained on the screen and the diameter is measured from one intimal surface to the other using callipers. The vessel diameter was taken as the mean of five separate readings (Struyk, Pipers, Wladimiroff, Lotgering, Tonge & Bom, 1985). All measurements were taken at least 3 cm away from the bifurcation in order to reduce 17S l-ity I'A L' RICISE AM) 1,1\11i llAf--\I()I))AAM1('S interference from turbulence, although theoretically time-averaged mean velocity makes no assumption of flow profile (Evans, McDicken, Skidmore & Woodcock, 1989).…”

Section: Blood Flowmentioning

confidence: 99%

Section: Blood Flowmentioning

confidence: 99%

Haemodynamic and metabolic responses of the lower limb after high intensity exercise in humans

Hussain¹,

Smith²,

Medbak³

et al. 1996

Experimental Physiology

View full text Add to dashboard Cite

SUMMARYThis study assessed blood flow in the common femoral, superficial femoral and profunda femoris arteries, the effects of vasodilator metabolites and changes in blood pressure and pulse during recovery after high intensity exercise (Wingate test). Mean common femoral artery flow increased sevenfold in response to the exercise. The subsequent decline in mean common femoral artery flow was mono-exponential with a mean time constant of 19 min. The post-exercise increase in profunda femoris artery flow (ninefold) was significantly greater than the superficial femoral artery flow (fourfold, P < 0.05). Systolic blood pressure and heart rate decreased monotonically throughout recovery. In contrast, diastolic blood pressure showed a significant fCll below batseline at 3 min (P < 0 05) with a return to baseline at 60 min. The greatest drop below baseline (approximately 20 mmHg) occurred around 7 min. Lactate reached a maximum of 13 6 + 2 3 mmol 1 at 8 min (P < 0.05) and was still significantly above baseline at 60 min. pH remained below 7-2 until 20 min of recovery. The results demonstrate that following high intensity exercise, blood flow to the limbs appears to be controlled by complex interactions of various vaso-active metabolites, each contributing proportionally more at different times during recovery.

show abstract

“…The diameter of the portal vein depends on respiration, and, therefore, the diameter of the PV was measured under respiratory suspension during expiration. Despite numerous methods described in the literature for determining a mean vessel diameter to account for caliber fluctuations over time, the authors of this study did not see any relevant pulsatility in either AHC or AHP [15,16].…”

Section: Determination Of Vessel Diametermentioning

confidence: 54%

“…determining a mean vessel diameter to account for caliber fluctuations over time, the authors of this study did not see any relevant pulsatility in either AHC or AHP [15,16]. The insonation angle refers to the angle between the vessel to be measured and the transducer.…”

Section: Location Of the Probe Insonation Angle And Doppler Windowmentioning

confidence: 90%

The Doppler Perfusion Index of the Liver and the Underlying Duplex Sonography of Visceral Vessels—A Systematic and Comprehensive Evaluation of Reproducibility

Lueders,

Gladitz,

Bauer

et al. 2024

Diagnostics

View full text Add to dashboard Cite

Prior to the curative resection of colorectal carcinoma (CRC) or pancreatic ductal adenocarcinoma (PDAC), the exclusion of hepatic metastasis using cross-sectional imaging is mandatory. The Doppler perfusion index (DPI) of the liver is a promising method for detecting occult liver metastases, but the underlying visceral duplex sonography is critically viewed in terms of its reproducibility. The aim of this study was to investigate systematically the reproducibility of the measured variables, the calculated blood flow, and the DPI. Between February and September 2023, two examinations were performed on 80 subjects within a period of 0–30 days and at two previously defined quality levels, aligned to the German standards of the DEGUM. Correlation analyses were carried out using Pearson’s correlation coefficient (PCC) and the intraclass correlation coefficient (ICC). The diameters, blood flow, and DPI showed a high degree of agreement (PCC of 0.9 and ICC of 0.9 for AHP). Provided that a precise standard of procedure is adhered to, the Doppler examination of AHC, AHP, and PV yields very reproducible blood flows and DPI, which is a prerequisite for a comprehensive investigation of its prognostic value for the prediction of metachronous hepatic metastasis in the context of curatively treated CRC or PDAC.

show abstract

The time-distance recorder as a means of improving the accuracy of fetal blood flow measurements

Cited by 13 publications

References 13 publications

Accuracy of Volumetric Flow Rate Measurements

Accuracy of Volumetric Flow Rate Measurements

Haemodynamic and metabolic responses of the lower limb after high intensity exercise in humans

The Doppler Perfusion Index of the Liver and the Underlying Duplex Sonography of Visceral Vessels—A Systematic and Comprehensive Evaluation of Reproducibility

Contact Info

Product

Resources

About