Shear wave elastography plaque characterization with mechanical testing validation: a phantom study

Widman, Erik; Maksuti, Elira; Larsson, Daniel H.; Urban, Matthew W.; Bjällmark, Anna; Larsson, Matilda

doi:10.1088/0031-9155/60/8/3151

Cited by 65 publications

(59 citation statements)

References 48 publications

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“…Ramnarine et al (2014) recently conducted a study involving eighty-one patients and demonstrated that shear wave elastography (SWE) is able to quantify carotid plaque elasticity and provide clinically relevant information to help identify unstable carotid plaques (Ramnarine et al 2014). Widman et al (2015) compared shear moduli of hard and soft plaques in vessel phantoms measured using SWE to mechanical testing results, and validated the feasibility of characterizing in vivo carotid plaque using SWE (Widman et al 2015). Korukonda et al (2013) studied sparse-array elastography and compared it to plane-wave imaging and compounded-plane-wave imaging on simulated vessel and vessel phantoms (Korukonda et al 2013).…”

Section: Introductionmentioning

confidence: 83%

Classification of Symptomatic and Asymptomatic Patients with and without Cognitive Decline Using Non-invasive Carotid Plaque Strain Indices as Biomarkers

Wang

Jackson

Mitchell

et al. 2016

Ultrasound in Medicine & Biology

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Vascular cognitive decline may be caused by micro-emboli generated from carotid plaque instability. We have previously shown that maximum strain indices in carotid plaque were significantly correlated with cognitive function. In this paper, we examine these associations with a larger sample size, along with performance evaluation of these maximum strain indices to predict cognitive impairment. Ultrasound-based strain imaging and cognition assessment were conducted on 75 human subjects. Patients underwent one of two standardized cognitive test batteries, using either the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) or the National Institute of Neurological Disorder and Stroke-Canadian Stroke Network (NINDS-CSN) Vascular Cognitive Impairment Harmonization Standards (60-minute). Scores were standardized within each battery to allow these data to be combined across all participants. Radiofrequency signals for ultrasound strain imaging were acquired on the carotid arteries using either a Siemens Antares with a VFX 13-5 linear array transducer or a Siemens S2000 with a 18L6 linear array transducer. The same hierarchical block-matching motion tracking algorithm developed in our laboratory was utilized to estimate accumulated axial, lateral, and shear strain indices in carotid plaque with inclusion of adventitia regardless of the ultrasound system and transducer used. Associations between cognitive z-scores and maximum strain indices were examined using Pearson’s correlation coefficients. Maximum strain indices were also utilized to predict cognitive impairment using ROC analysis. All correlations between maximum strain indices and total cognition were statistically significant (p<0.05), indicating that these indices have good utility for predicting cognitive impairment. Maximum lateral strain indices provide an AUC of 0.85 for symptomatic patients, and 0.68 for asymptomatic patients. Our results demonstrate the important relationship of maximum strain indices and cognitive function, and the feasibility of using maximum strain indices to predict cognitive decline with inclusion of adventitia layer into the segmentation of plaque.

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Section: Introductionmentioning

confidence: 83%

Classification of Symptomatic and Asymptomatic Patients with and without Cognitive Decline Using Non-invasive Carotid Plaque Strain Indices as Biomarkers

Wang

Jackson

Mitchell

et al. 2016

Ultrasound in Medicine & Biology

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“…These studies show that the technique is clinically safe and provides reproducible shear wave velocity estimates, also in vivo [3,4,7]. Experimental studies with vessel-mimicking phantoms also showed that local regions with softer tissue can be detected [4,8,9], hence they show that the technique might be used to detect soft lipidrich/necrotic cores. However, all these studies image arteries in a longitudinal imaging view, which is useful only for imaging the centre plane of the vessel and not for detecting lipids over the full vessel circumference.…”

Section: Introductionmentioning

confidence: 63%

“…Especially this last assumption is not valid for thin-walled vessels. Because of the limited thickness of the tissue, dispersion, refraction and reflection will occur as also demonstrated for vascular shear wave elastography in longitudinal imaging planes [2,7,9]. In those phantom studies shear wave phase velocity instead of group velocity was found to allow a more correct quantification of tissue stiffness.…”

Section: Discussionmentioning

confidence: 95%

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Shear wave elastography for lipid content detection in transverse arterial cross-sections

Hansen

Pernot

Chatelin

et al. 2015

2015 IEEE International Ultrasonics Symposium (IUS)

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Rupture of plaques in atherosclerotic carotid arteries is a main cause of stroke. Plaques with a large soft lipidrich core are more prone to rupture than predominantly fibrous, stiff plaques. Detecting and monitoring the presence of lipids in plaques noninvasively and fast remains challenging. Ultrasound shear wave elastography is fast and noninvasive. Experimental studies showed that detection of locally softer regions in vesselmimicking phantoms is possible. However, these studies only report imaging in a longitudinal imaging plane. Since it is not possible to detect lipids over the full vessel circumference when imaging in a longitudinal plane, this study investigates the feasibility of shear wave elastography in transverse imaging planes. A SuperSonic Imagine Aixplorer equipped with a linear array probe was used to induce shear waves in vessel-mimicking polyvinylalcohol phantoms of varying dimensions and shear moduli using a single focused ultrasonic push (300 µs). The push was followed by 0° plane wave acquisitions (n = 100, PRF ≥ 10 kHz) to detect the axial motion induced in the vessel wall. To visualize the generated circumferentially propagating shear waves, axial motion maps were created showing the axial phase shift as a function of circumferential position for circular paths in the vessel wall. Approximately linearly propagating wave fronts were observed for all phantoms as a function of circumferential position. For homogeneous phantoms, one wave was observed, which made a roundtrip, whereas a slow and a fast wave were observed in two-layered 'soft plaque' phantoms suggesting that soft lipid-rich regions can be detected. Finally, preliminary in vivo results were obtained in a volunteer using a Verasonics ultrasound system which confirmed that creation of circumferentially propagating waves is also possible in vivo. Based on these observations we conclude that shear wave elastography in transverse imaging planes is feasible and promising for lipid-core detection in plaques of superficial arteries.

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“…However, with phantom studies [15] successfully resolving plaque stiffness over a range corresponding to what is reported for atherosclerotic plaque tissue [14], the performed study should serve as a proof-ofconcept example, with the ability to perform similar testing of a plaque investigated directly following surgical extraction.…”

Section: Discussionmentioning

confidence: 99%

An ex-vivo setup for characterization of atherosclerotic plaque using shear wave elastography and micro-computed tomography

Larsson

Roy

Gasser

et al. 2016

2016 IEEE International Ultrasonics Symposium (IUS)

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Quantification of the mechanical properties of atherosclerotic plaque has shown to be important in assessing carotid artery plaque vulnerability. For such, shear wave elastography (SWE) has been applied on both in-vitro and in-vivo setups. The aim of this study was to build an ex-vivo setup for combined evaluation of plaque characteristics using SWE and micro-computed tomography (µCT). As a proof-of-concept of the constructed experimental setup, a single human carotid plaque specimen was extracted during carotid endarterectomy. The plaque was imaged in the µCT system, and subsequently imaged using SWE. For the SWE measurement, group and phase velocity was extracted from the obtained in-phase/quadrature data, with its spatial distribution being compared to anatomical features visible in the µCT images. The results indicated wave velocity changes at boundaries identified in the µCT, with group velocity data slightly increasing when entering a calcified nodule. Additionally, µCT images seemed to provide good contrast between several plaque constituens using the defined imaging settings. Overall, the study represents a proof-of-concept for detailed ex-vivo plaque analysis using combined SWE and µCT, with obtained wave speed and shear modulus values falling within observed values for atherosclerotic plaque tissue. With an experimental setup defined, future studies on carotid plaque behaviour both in SWE and µCT is enabled, where a large-scale plaque study could be performed to investigate the ability of SWE to differentiate between different plaque types.

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Shear wave elastography plaque characterization with mechanical testing validation: a phantom study

Cited by 65 publications

References 48 publications

Classification of Symptomatic and Asymptomatic Patients with and without Cognitive Decline Using Non-invasive Carotid Plaque Strain Indices as Biomarkers

Classification of Symptomatic and Asymptomatic Patients with and without Cognitive Decline Using Non-invasive Carotid Plaque Strain Indices as Biomarkers

Shear wave elastography for lipid content detection in transverse arterial cross-sections

An ex-vivo setup for characterization of atherosclerotic plaque using shear wave elastography and micro-computed tomography

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