Evaluation of methods to derive blood flow velocity from 1000 fps high-speed angiographic sequences (HSA) using optical flow (OF) and computational fluid dynamics (CFD)

Shields, Allison; Nagesh, Swetadri Vasan Setlur; Ionita, Ciprian N.; Bednarek, Daniel R.; Rudin, Stephen

doi:10.1117/12.2580881

Cited by 15 publications

(16 citation statements)

References 4 publications

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“…Alternative particle tracers, such as ethiodol droplets, can provide higher contrast to noise ratio. 6 However, there are so far no particle tracers that can be used to perform X-PIV in-vivo, and therefore research developing novel particle tracers for 3D-XPIV will be necessary for real-time clinical applications. Further work modelling CFD particle trajectories would offer a direct comparison of trajectories that may partially explain discrepencies between CFD and 3D-XPIV values.…”

Section: Discussionmentioning

confidence: 99%

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Determining 3D distributions of pulsatile blood flow using orthogonal Simultaneous Biplane High-Speed Angiography (SB-HSA) with 1000 fps CdTe photon counting detectors for 3D X-ray Particle Image Velocimetry (3D-XPIV) compared to results using Computational Fluid Dynamics (CFD)

Shields

Vanderbilt

et al. 2023

Medical Imaging 2023: Biomedical Applications in Molecular, Structural, and Functional Imaging

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3D hemodynamic distributions are useful for the diagnosis and treatment of aneurysms. Detailed blood-flow patterns and derived velocity maps can be obtained using 1000 fps High Speed Angiography (HSA). The novel orthogonal Simultaneous Biplane High-Speed Angiography (SB-HSA) system enables flow information to be quantified in multiple planes, and with additional components of flow at depth, accurate 3D flow distributions are available. Computational Fluid Dynamics (CFD) is the current standard for derivation of volumetric flow distributions, but obtaining solution convergence is computationally expensive and time intensive. More importantly, matching in-vivo boundary conditions is non-trivial. Therefore, an experimentally derived 3D flow distribution method could offer realistic results with less computation time. Using SB-HSA image sequences, 3D X-Ray Particle Image Velocimetry (3D-XPIV) was explored as a new method for assessing 3D flow. 3D-XPIV was demonstrated using an in-vitro setup, where a patient-specific internal carotid artery aneurysm model was attached to a flow loop, and an automated injection of iodinated microspheres was used as a flow tracer. Two 1000 fps photon-counting detectors were placed orthogonally with the aneurysm model in the FOV of both planes. Frame-synchronization of the two detectors made correlation of single-particle velocity components at a given timepoint possible. With frame-rates of 1000 fps, small particle displacements between frames resolved realistic timevarying flow, where accurate velocity distributions depended on near-instantaneous velocities. 3D-XPIV velocity distributions were compared to CFD velocity distributions, where the simulation boundary conditions matched the in-vitro setup. Results showed similar velocity distributions between CFD and 3D-XPIV.

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Section: Discussionmentioning

confidence: 99%

“…Unlike CFD, 3D-XPIV can be performed immediately after HSA image acquisition, requiring less computational power and time. 4…”

Section: Introductionmentioning

confidence: 99%

Determining 3D distributions of pulsatile blood flow using orthogonal Simultaneous Biplane High-Speed Angiography (SB-HSA) with 1000 fps CdTe photon counting detectors for 3D X-ray Particle Image Velocimetry (3D-XPIV) compared to results using Computational Fluid Dynamics (CFD)

Shields

Vanderbilt

et al. 2023

Medical Imaging 2023: Biomedical Applications in Molecular, Structural, and Functional Imaging

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“…Additional evaluation is required, but based on this analysis, reflux lengths should be limited to low values (controlled by contrast injection rate) if the angiographic acquisition will be at low frame rates. Extremely high frame rate detectors are in development, 37,45 and once made available for clinical use, these would be extremely valuable to any angiographic contrast flow evaluations.…”

Section: Discussionmentioning

confidence: 99%

“…Contrast concentration–time curves have, for example, been parameterized by their first moments, peaks, or slopes and have been fit with various functions (such as lag normal, gamma variate, or exponential) to extract transit‐time/dilution measures or to estimate treatment efficacy 28–31 . Increased computational power and flat‐panel detectors have allowed for pixel‐by‐pixel tracking of contrast intensities and generation of color‐coded parametric maps, use of computational fluid dynamics, and extraction of flow measures using three‐dimensional contrast transport data 30,32–37 . However, the flow estimation accuracy of even these recent techniques seems to be limited to very specific conditions—required observation of cardiac pulsatility in contrast time–concentration curves, imaging of straight vessel segments without any branch overlap, use of ultrahigh image acquisition rates with poor vessel opacification, or observation of high accuracies only in benchtop studies with steady flow in tubes.…”

Section: Introductionmentioning

confidence: 99%

“…[28][29][30][31] Increased computational power and flat-panel detectors have allowed for pixel-by-pixel tracking of contrast intensities and generation of color-coded parametric maps, use of computational fluid dynamics, and extraction of flow measures using three-dimensional contrast transport data. 30,[32][33][34][35][36][37] However, the flow estimation accuracy of even these recent techniques seems to be limited to very specific conditions-required observation of cardiac pulsatility in contrast time-concentration curves, imaging of straight vessel segments without any branch overlap, use of ultrahigh image acquisition rates with poor vessel opacification, or observation of high accuracies only in benchtop studies with steady flow in tubes. Thus, angiographic flow estimation does not yet have reliable accuracy and precision to be routinely useful in the clinical setting.…”

Section: Introductionmentioning

confidence: 99%

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A novel angiographic method to estimate arterial blood flow rates using contrast reflux: Effect of injection parameters

et al. 2022

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Background Contrast reflux, which is the retrograde movement of contrast against flow direction, is commonly observed during angiography. Despite a vast body of literature on angiography, the hemodynamic factors affecting contrast reflux have not been studied. Numerous methods have been developed to extract flow from angiography, but the reliability of these methods is not yet sufficient to be of routine clinical use. Purpose To evaluate the effect of baseline blood flow rates and injection conditions on the extent of contrast reflux. To estimate arterial flow rates based on measurement of contrast reflux length. Materials and methods Iodinated contrast was injected into an idealized tube as well as a physiologically accurate model of the cervico‐cerebral vasculature. A total of 194 high‐speed angiograms were acquired under varying “blood” flow rates and injection conditions (catheter size, injection rate, and injection time). The length of contrast reflux was compared to the input variables and to dimensionless fluid dynamics parameters at the catheter‐tip. Arterial blood flow rates were estimated using contrast reflux length as well as a traditional transit‐time method and compared to measured flow rates. Results Contrast reflux lengths were significantly affected by contrast injection rate (p < 0.0001), baseline blood flow rate (p = 0.0004), and catheter size (p = 0.04), but not by contrast injection time (p = 0.4). Reflux lengths were found to be correlated to dimensionless fluid dynamics parameters by an exponential function (R2 = 0.6–0.99). When considering the entire dataset in unison, flow estimation errors with the reflux‐length method (39% ± 33%) were significantly higher (p = 0.003) than the transit‐time method (33% ± 36%). However, when subgrouped by catheter, the error with the reflux‐length method was substantially reduced and was significantly lower (14% ± 14%, p < 0.0001) than the transit‐time method. Conclusion Results show correlations between contrast reflux length and baseline hemodynamic parameters that have not been reported previously. Clinically relevant blood flow rate estimation is feasible by simple measurement of reflux length. In vivo and clinical studies are required to confirm these correlations and to refine the methodology of estimating blood flow by reflux.

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Application of 1,000 fps High-Speed Angiography to In-Vitro Hemodynamic Evaluation of Left Ventricular Assist Device Outflow Graft Configurations

et al. 2023

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Left ventricular assist device (LVAD)-induced hemodynamics are characterized by fast-moving flow with large variations in velocity, making quantitative assessments difficult with existing imaging methods. This study demonstrates the ability of 1,000 fps high-speed angiography (HSA) to quantify the effect of the surgical implantation angle of a LVAD outflow graft on the hemodynamics within the ascending aorta in vitro. High-speed angiography was performed on patientderived, three-dimensional-printed optically opaque aortic models using a nonsoluble contrast media, ethiodol, as a flow tracer. Outflow graft configuration angles of 45° and 90° with respect to the central aortic axis were considered. Projected velocity distributions were calculated from the high-speed experimental sequences using two methods: a physics-based optical flow algorithm and tracking of radio-opaque particles. Particle trajectories were also used to evaluate accumulated shear stress. Results were then compared with computational fluid dynamics (CFD) simulations to confirm the results of the high-speed imaging method. Flow patterns derived from HSA coincided with the impingement regions and recirculation zones formed in the aortic root as seen in the CFD for both graft configurations. Compared with the 45° graft, the 90° configuration resulted in 81% higher two-dimensionalprojected velocities (over 100 cm/s) along the contralateral wall of the aorta. Both graft configurations suggest elevated accumulated shear stresses along individual trajectories. Compared with CFD simulations, HSA successfully characterized the fast-moving flow and hemodynamics in each LVAD graft configuration in vitro, demonstrating the potential utility of this technology as a quantitative imaging modality. ASAIO

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Evaluation of methods to derive blood flow velocity from 1000 fps high-speed angiographic sequences (HSA) using optical flow (OF) and computational fluid dynamics (CFD)

Cited by 15 publications

References 4 publications

Determining 3D distributions of pulsatile blood flow using orthogonal Simultaneous Biplane High-Speed Angiography (SB-HSA) with 1000 fps CdTe photon counting detectors for 3D X-ray Particle Image Velocimetry (3D-XPIV) compared to results using Computational Fluid Dynamics (CFD)

Determining 3D distributions of pulsatile blood flow using orthogonal Simultaneous Biplane High-Speed Angiography (SB-HSA) with 1000 fps CdTe photon counting detectors for 3D X-ray Particle Image Velocimetry (3D-XPIV) compared to results using Computational Fluid Dynamics (CFD)

A novel angiographic method to estimate arterial blood flow rates using contrast reflux: Effect of injection parameters

Application of 1,000 fps High-Speed Angiography to In-Vitro Hemodynamic Evaluation of Left Ventricular Assist Device Outflow Graft Configurations

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