A review of Doppler ultrasound quality assurance protocols and test devices

Abstract

a b s t r a c tIn this paper, an overview of Doppler ultrasound quality assurance (QA) testing will be presented in three sections. The first section will review the different Doppler ultrasound parameters recommended by professional bodies for use in QA protocols. The second section will include an evaluation and critique of the main test devices used to assess Doppler performance, while the final section of this paper will discuss which of the wide range of test devices have been found to be most suitable for inclusion in Doppler QA programmes. Pulsed Wave Spectral Doppler, Colour Doppler Imaging QA test protocols have been recommended over the years by various professional bodies, including the UK's Institute of Physics and Engineering in Medicine (IPEM), the American Institute for Ultrasound in Medicine (AIUM), and the International Electrotechnical Commission (IEC). However, despite the existence of such recommended test protocols, very few commercial or research test devices exist which can measure the full range of both PW Doppler ultrasound and colour Doppler imaging performance parameters, particularly quality control measurements such as: (i) Doppler sensitivity (ii) colour Doppler spatial resolution (iii) colour Doppler temporal resolution (iv) colour Doppler velocity resolution (v) clutter filter performance and (vi) tissue movement artefact suppression. In this review, the merits of the various commercial and research test devices will be considered and a summary of results obtained from published studies which have made use of some of these Doppler test devices, such as the flow, string, rotating and belt phantom, will be presented.© 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved. IntroductionThe importance of assessing the quality of Doppler ultrasound systems is apparent considering that the result or product of Doppler ultrasound examinations is frequently directed toward a well-defined clinical question concerning blood flow [1]. For example, Doppler ultrasound is used to determine the level of stenosis by examining the changes in blood flow in the vessel of interest, and to determine whether flow is present in a tight stenosis. Another use is to determine if changes have occurred in blood flow in transplanted kidneys [1e3]. Indeed, the use of Doppler ultrasound has become more widespread over the last decade, largely due to advances in transducer technology, digital electronics and clutter filter algorithms, with a corresponding improvement in the Doppler sensitivity, axial resolution within the sample volume and the low velocity detection capabilities of modern systems [3]. With this increasing use of Doppler ultrasound techniques, it is of paramount importance that ultrasound systems meet the requirements of each of the different clinical applications and that the quality of the information is maintained throughout the lifetime of the ultrasound system. To this end, performance and quality control tests are carried out to determine firstly that th...

Technical Note: A new phantom design for routine testing of Doppler ultrasound

“…Sixteen pertinent Doppler performance measurements have been reported in Browne's review of Doppler quality testing. 2 Of these, this phantom design would be useful for obtaining measurements of mean velocity estimation as described earlier and flow direction by using color Doppler while draining the phantom in both directions. Angle correction software accuracy, which would be implicitly tested with the mean velocity estimation, could also be evaluated.…”

“…A review of commercially available Doppler ultrasound phantoms has been discussed at some length by Browne in 2014. 2 In this review, two main phantom designs as well as others were discussed for Doppler ultrasound testing. The first uses a filament (string) driven by a motor and running on a set of pulleys.…”

“…Many of these are not commercially available but have specific advantages and are discussed in further detail elsewhere. 2 While there are very few regulations or requirements for Doppler quality control testing with any type of phantom, the phantom described here can help to make Doppler ultrasound quality control more practical in clinical settings, on a routine basis.…”

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

“…Assessment of the latter is recommended through approved quality assurance and control processes 1 [8] [9] that aim to uncover nonconformity and identify deviations from product performance specification [10]. Evaluation of performance is typically made through the acquisition of images obtained using a test object specifically designed to provide consistent results.…”

“…Ideally a flow phantom should produce a known flow field and mimic the in vivo situation, including motion. This is challenging, and in reality physical flow phantoms deliver either (i) a complex flow (whose precise details are unknown) based on a rig whose flows are physiologically relevant [11] [12], or (ii) a simple flow (or alternative [10]) that is explicitly known, designed specifically for scanner calibration/assessment [13] [14] [15]. Arguably many current phantom designs implement flows that bear little resemblance to the complex physiological and pathological flows encountered in the clinic (i.e.…”