The Ring Vortex: Concepts for a Novel Complex Flow Phantom for Medical Imaging

Ferrari, Simone; Ambrogio, Simone; Walker, Adrian; Verma, Prashant Kumar; Narracott, Andrew; Wilkinson, Iain D.; Fenner, John

doi:10.4236/ojmi.2017.71004

Cited by 7 publications

(4 citation statements)

References 27 publications

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“…The ring vortex flow is well suited to its role as a reference flow because it offers characteristics like stability, predictability, reproducibility and controllability [20,21,26,27] [1,2,8,28,29,30,31,32,33,34,35,36]. Vortex rings are natural fluid phenomena that are known to balance flow within the chambers of the heart or may be observed in the presence of vessel bifurcations or pathological conditions, such as stenosis and aneurysm.…”

Section: Discussionmentioning

confidence: 99%

“…Images captured by an imaging system can be referenced to the features of the flow, permitting characterisation of imaging system performance. Bulk features (ring speed, size) are readily established through simple optical/video methods [20] whereas finer details of the flow benefit from technologies such as particle image velocimetry (PIV) or even computational fluid dynamics (CFD) [21].…”

Section: The Assembled Systemmentioning

confidence: 99%

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A complex flow phantom for medical imaging: ring vortex phantom design and technical specification

Ambrogio

Walker²,

Narracott

et al. 2019

Journal of Medical Engineering & Technology

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Cardiovascular fluid dynamics exhibit complex flow patterns, such as recirculation and vortices. Quantitative analysis of these complexities supports diagnosis, leading to early prediction of pathologies. Quality Assurance of technologies that image such flows is challenging but essential, and to this end, a novel, cost-effective, portable, complex flow phantom is proposed and the design specifications are provided. The vortex ring is the flow of choice because it offers patterns comparable to physiological flows and is stable, predictable, reproducible and controllable. This design employs a piston/cylinder system for vortex ring generation, coupled to an imaging tank full of fluid, for vortex propagation. The phantom is motor-driven and by varying piston speed, piston displacement and orifice size, vortex rings with different characteristics can be produced. Two measurement methods, namely Laser-PIV and an optical/video technique, were used to test the phantom under a combination of configurations. Vortex rings with a range of travelling velocities (approximately 1-80cm/s) and different output-orifice diameters (10-25mm) were produced with reproducibility typically better than +/-10%. Although ultrasound compatibility has been demonstrated, longer-term ambitions include adapting the design to support comparative studies with different modalities, such as MRA and X-ray-CTA.

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Section: Discussionmentioning

confidence: 99%

Section: The Assembled Systemmentioning

confidence: 99%

A complex flow phantom for medical imaging: ring vortex phantom design and technical specification

Ambrogio

Walker²,

Narracott

et al. 2019

Journal of Medical Engineering & Technology

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“…The ring vortex flow phantom has been developed to generate such flows, producing reproducible ring vortices over a range of speeds and sizes [4]. Reproducibility is vital for application as a medical flow phantom, and its reference flows have also been demonstrated as predictable, controllable and stable [5]. In addition to these attributes, the complexity of the ring vortex flow is sufficiently demanding to challenge modern flow imaging systems, with flow features directly relevant to intra-cardiac flow profiles [6].…”

Section: Introductionmentioning

confidence: 99%

Quality Assuring a Ring Vortex Flow Phantom in Real-Time

Matthews¹,

Simatwo²,

Narracott³

et al. 2023

OJMI

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Introduction:The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 -70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities.

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“…As it is nearly impossible to study the effect of all parameters, given their wide range, experimentally as well as analytically, it is required to find alternative ways to accurately study the indoor concentration distribution patterns of decay products. In recent times, Computational Fluid Dynamics (CFD) approach has been established as a convenient substitute for restrictive experimental and theoretical approaches; offering fast, reasonable and confident solutions in various research contexts [16,17] including aerosol science and technology [18,19] and radon thoron studies [20,21].…”

Section: Introductionmentioning

confidence: 99%

A Computational Fluid Dynamics code for aerosol and decay-product studies in indoor environments

Agarwal

Sahoo

Kumar

et al. 2021

J Radioanal Nucl Chem

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In the present work, Computational Fluid Dynamics (CFD) code has been used to simulate the behaviour of aerosols and decay products of 222 Rn/ 220 Rn in indoor environments. The code has been incorporated with simulation modules describing relevant physical processes governing the aerosol and decay product dynamics such as particle deposition, gravitational settling, thermophoresis, coagulation and size dependent attachment of decay products to aerosol. Subsequently, reliability and consistency of the CFD code has been evaluated and validated by comparing simulated results with analytical and simulation results of well-known cases reported in literature. Comparison showed a good agreement within ± 3.5%.

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The Ring Vortex: Concepts for a Novel Complex Flow Phantom for Medical Imaging

Cited by 7 publications

References 27 publications

A complex flow phantom for medical imaging: ring vortex phantom design and technical specification

A complex flow phantom for medical imaging: ring vortex phantom design and technical specification

Quality Assuring a Ring Vortex Flow Phantom in Real-Time

A Computational Fluid Dynamics code for aerosol and decay-product studies in indoor environments

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