scholarly journals Mathematical Models for Blood Flow Quantification in Dialysis Access Using Angiography: A Comparative Study

Diagnostics ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1771
Author(s):  
Nischal Koirala ◽  
Gordon McLennan
Keyword(s):  
Blood Flow ◽  
Curve Fitting ◽  
Cross Correlation ◽  
Blood Flow Rate ◽  
Flow Quantification ◽  
Dialysis Access ◽  
Gamma Variate ◽  
Correlation Algorithm ◽  
Angiography Suite ◽  
The Cross

Blood flow rate in dialysis (vascular) access is the key parameter to examine patency and to evaluate the outcomes of various endovascular interve7ntions. While angiography is extensively used for dialysis access–salvage procedures, to date, there is no image-based blood flow measurement application commercially available in the angiography suite. We aim to calculate the blood flow rate in the dialysis access based on cine-angiographic and fluoroscopic image sequences. In this study, we discuss image-based methods to quantify access blood flow in a flow phantom model. Digital subtraction angiography (DSA) and fluoroscopy were used to acquire images at various sampling rates (DSA—3 and 6 frames/s, fluoroscopy—4 and 10 pulses/s). Flow rates were computed based on two bolus tracking algorithms, peak-to-peak and cross-correlation, and modeled with three curve-fitting functions, gamma variate, lagged normal, and polynomial, to correct errors with transit time measurement. Dye propagation distance and the cross-sectional area were calculated by analyzing the contrast enhancement in the vessel. The calculated flow rates were correlated versus an in-line flow sensor measurement. The cross-correlation algorithm with gamma-variate curve fitting had the best accuracy and least variability in both imaging modes. The absolute percent error (mean ± SEM) of flow quantification in the DSA mode at 6 frames/s was 21.4 ± 1.9%, and in the fluoroscopic mode at 10 pulses/s was 37.4 ± 3.6%. The radiation dose varied linearly with the sampling rate in both imaging modes and was substantially low to invoke any tissue reactions or stochastic effects. The cross-correlation algorithm and gamma-variate curve fitting for DSA acquisition at 6 frames/s had the best correlation with the flow sensor measurements. These findings will be helpful to develop a software-based vascular access flow measurement tool for the angiography suite and to optimize the imaging protocol amenable for computational flow applications.

Research on Resistivity Measurement System of Submarine Sediment

2013 ◽  
Vol 455 ◽  
pp. 486-490
Author(s):  
Lai Jie Wu ◽  
Bin Ma ◽  
Yuan Hong Yang
Keyword(s):  
Measurement System ◽  
Cross Correlation ◽  
Resistivity Measurement ◽  
Matlab Simulation ◽  
Theoretical Derivation ◽  
Correlation Algorithm ◽  
Improve Accuracy ◽  
Voltage Signal ◽  
The Cross

This paper developed a resistivity measurement system on the platform of in-situ detector which based on seafloor drilling machine. In order to precisely process the weak voltage signal which outputted by the resistivity probe, the paper carried out the cross-correlation algorithm theoretical derivation and MATLAB simulation, then ported the algorithm to TMS320F28069 DSP processor and designed hardware. A mass of contrast experiment shows that the cross-correlation algorithm is an effective method to process weak signal. It can improve accuracy and anti-jamming ability of the submarine sediment resistivity measurement system. The method of submarine sediment resistivity measurement can be widely used in fields of marine geological survey, marine environment research, etc.

Cuffed-tunneled Femoral Catheter for Long-term Hemodialysis

2001 ◽  
Vol 24 (7) ◽  
pp. 443-446 ◽  
Author(s):  
K.M. Chow ◽  
C.C. Szeto ◽  
C.B. Leung ◽  
T. Y.H. Wong ◽  
P.K.T. Li
Keyword(s):  
Blood Flow ◽  
Blood Flow Rate ◽  
Hemodialysis Patients ◽  
Upper Extremities ◽  
Rank Test ◽  
Dialysis Access ◽  
Ptfe Graft ◽  
Risk Of Infection ◽  
Femoral Catheter

Background Hemodialysis access is a challenging problem in patients with exhausted dialysis access sites of their upper extremities. Femoral arterio-venous polytetrafluoroethylene (PTFE) graft is often necessary. The safety and efficacy of cuffed tunneled catheters at the femoral site for long-term hemodialysis has not been extensively studied. Methods We inserted 14 cuffed-tunneled femoral catheters in 11 hemodialysis patients with exhausted dialysis access sites of their upper extremities. Access survival and risk of infection were compared with the 11 femoral PTFE grafts in 10 patients of our center during the same period. The choice of dialysis access was determined by the individual nephrologist. Access survival was defined as the achievement of a blood flow rate of at least 180 ml/min. Results The median survival of tunneled femoral catheter and PTFE graft were 166 days and 560 days respectively (log-rank test, p = 0.33). Seven of the 14 tunneled femoral catheter remained in use 3 months after insertion. The incidence of catheter- or graft-related infection was 0.38 and 0.23 episodes per 100 catheter / graft days for tunneled femoral catheters and PTFE graft respectively (p = 0.6). Five tunneled catheters and one PTFE graft had to be removed because of infection. Blood flow rates achieved were comparable between tunneled femoral catheter and PTFE graft. Conclusions Our preliminary data suggest that the cuffed tunneled femoral catheter has reasonable access survival and an acceptable risk of infection. It may provide a safe and effective access for long-term hemodialysis patients with exhausted access in their upper extremities, especially high risk patients who are not suitable for femoral PTFE graft creation.

Application of Cross-Correlation Algorithm in Submarine Sediment Resistivity Measurement

2013 ◽  
Vol 446-447 ◽  
pp. 1123-1128
Author(s):  
Lai Jie Wu ◽  
Bin Ma ◽  
Qi Chen ◽  
Wei Jiang
Keyword(s):  
Measurement System ◽  
Cross Correlation ◽  
Resistivity Measurement ◽  
Matlab Simulation ◽  
Theoretical Derivation ◽  
Correlation Algorithm ◽  
Improve Accuracy ◽  
Voltage Signal ◽  
The Cross

This paper developed a resistivity measurement system on the platform of in-situ detector which based on seafloor drilling machine. In order to precisely process the weak voltage signal which outputted by the resistivity probe, the paper carried out the cross-correlation algorithm theoretical derivation and MATLAB simulation, then ported the algorithm to TMS320F28069 DSP processor and designed hardware. A mass of contrast experiment shows that the cross-correlation algorithm is an effective method to process weak signal. It can improve accuracy and anti-jamming ability of the submarine sediment resistivity measurement system. The method of submarine sediment resistivity measurement can be widely used in fields of marine geological survey, marine environment research, etc.

Two-Component Horizontal Aerosol Motion Vectors in the Atmospheric Surface Layer from a Cross-Correlation Algorithm Applied to Scanning Elastic Backscatter Lidar Data*

2012 ◽  
Vol 29 (11) ◽  
pp. 1585-1602 ◽  
Author(s):  
Shane D. Mayor ◽  
Jennifer P. Lowe ◽  
Christopher F. Mauzey
Keyword(s):  
Cross Correlation ◽  
Empirical Relationship ◽  
Sonic Anemometer ◽  
Leading Edge ◽  
Horizontal Wind ◽  
Motion Vectors ◽  
Correlation Algorithm ◽  
Sonic Anemometers ◽  
Two Component ◽  
The Cross

Abstract Two-component horizontal motion vectors of aerosol features were calculated by applying a cross-correlation algorithm to square image blocks extracted from consecutive pairs of elastic backscatter lidar scans. The resulting vector components were compared with corresponding horizontal wind components from tower-mounted sonic anemometers located at the center of the image blocks. In the analysis 180 245 pairs of vectors derived from 75 days of field data collected between 19 March and 11 June 2007 were used. Examples of time series comparisons from 4-h periods during light, strong, and changing wind conditions are presented. Mean signal-to-noise ratios (SNRs) of the block backscatter data, maxima of the cross-correlation functions (CCFs), observed wind speed, and turbulent kinetic energy (TKE) were also calculated for each velocity component comparison. The correlation between the lidar-derived motion components and sonic anemometer wind components tends to be highest during light wind conditions with low TKE. An empirical relationship is presented that enables the elimination of vectors that are likely to be significantly different than the anemometer measurement. When applied to the entire set of scans available, this quality control (QC) method increases the correlation between the two forms of measurements. Finally, the cross-correlation algorithm and QC method are applied to a mesh of locations over pairs of scans. Two examples of two-dimensional and two-component vector flow fields are shown. In one case, the flow field reveals a rotational circulation associated with a vortex and, in the other case, convergence and transport near the leading edge of a density current front.

Astronomical Image Matching Based on the Cross-Correlation Algorithm

2014 ◽  
Vol 989-994 ◽  
pp. 3827-3833
Author(s):  
Ji Jun Sun
Keyword(s):  
Image Registration ◽  
Image Matching ◽  
Cross Correlation ◽  
Medical Image Analysis ◽  
Correlation Method ◽  
Remote Sensing Data ◽  
Correlation Algorithm ◽  
Astronomical Image ◽  
The Cross ◽  
Astronomical Images

Image registration is widely used in the areas of image fusion, target tracking, remote sensing data analysis, medical image analysis such as organization pathological changes, under the constantly exploring to the image registration technology. In this paper astronomical image matching based on the cross-correlation algorithm is proposed and we focuses on adopting the registration form using the cross-correlation method after segmenting the astronomical images. The method can effectively solve the difficulties of the overall matching, represent the salient regions of features and implement local matching.

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