Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2008 Nov 21;53(22):6377-94.
doi: 10.1088/0031-9155/53/22/008. Epub 2008 Oct 21.

Preliminary in vivo atherosclerotic carotid plaque characterization using the accumulated axial strain and relative lateral shift strain indices

Hairong Shi  1 , Carol C Mitchell, Matthew McCormick, Mark A Kliewer, Robert J Dempsey, Tomy Varghese
Affiliations

Preliminary in vivo atherosclerotic carotid plaque characterization using the accumulated axial strain and relative lateral shift strain indices

Hairong Shi et al. Phys Med Biol. .

Abstract

In this paper, we explore two parameters or strain indices related to plaque deformation during the cardiac cycle, namely, the maximum accumulated axial strain in plaque and the relative lateral shifts between plaque and vessel wall under in vivo clinical ultrasound imaging conditions for possible identification of vulnerable plaque. These strain indices enable differentiation between calcified and lipidic plaque tissue utilizing a new perspective based on the stiffness and mobility of the plaque. In addition, they also provide the ability to distinguish between softer plaques that undergo large deformations during the cardiac cycle when compared to stiffer plaque tissue. Soft plaques that undergo large deformations over the cardiac cycle are more prone to rupture and to release micro-emboli into the cerebral bloodstream. The ability to identify vulnerable plaque, prone to rupture, would significantly enhance the clinical utility of this method for screening patients. We present preliminary in vivo results obtained from ultrasound radio frequency data collected over 16 atherosclerotic plaque patients before these patients undergo a carotid endarterectomy procedure. Our preliminary in vivo results indicate that the maximum accumulated axial strain over a cardiac cycle and the maximum relative lateral shift or displacement of the plaque are useful strain indices that provide differentiation between soft and calcified plaques.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Illustration of the procedure using which the region of interest is tracked over all the frames within the cardiac cycle.
Figure 2
Figure 2
Region of the ultrasound B-mode image and accumulated axial strain for patient 9 with a soft plaque: (a) B-mode image of the soft plaque (the region marked by white arrow), (b) a typical axial strain image, (c) the accumulated axial strain versus frame number and (d) the cross-correlation coefficient versus frame number.
Figure 3
Figure 3
Region with a heterogeneous plaque on the ultrasound B-mode image and accumulated axial strain for the same patient: (a) B-mode image of heterogeneous plaque (the region marked by white arrow), (b) a typical axial strain image, (c) the accumulated axial strain versus frame number and (d) the cross-correlation coefficient versus frame number.
Figure 4
Figure 4
Ultrasound B-mode image and accumulated axial strain for patient 3 with a calcified plaque: (a) B-mode image of the calcified plaque (the region marked by white dashed circle), (b) a typical strain image, (c) the accumulated axial strain versus number of frames and (d) the cross-correlation coefficient versus number of frames.
Figure 5
Figure 5
Histogram of the accumulated axial strain of (a) calcified plaques and (b) soft plaques.
Figure 6
Figure 6
(a) Relative lateral shift between plaque and artery wall and the linear fit of this shift to detrend the data; (b) the relative lateral shift between plaque and artery wall with general linear trend removed; (c) the 2D cross-correlation coefficient for the ROI.
Figure 7
Figure 7
Histograms for the relative lateral shifts between plaque and artery wall ROIs, respectively: (a) calcified plaque and (b) soft plaque.
Figure 8
Figure 8
Plot of the maximum relative lateral shift versus the maximum accumulated axial strain for both calcified plaque and soft plaque.
Figure 9
Figure 9
ROC curve for the maximum accumulated axial strain estimated from the in vivo plaque data.
Figure 10
Figure 10
ROC curve of the maximum relative lateral shift parameter estimated from the in vivo plaque data.
See this image and copyright information in PMC

References

    1. AbuRahma AF, Wulu JT, Jr, Crotty B. Carotid plaque ultrasonic heterogeneity and severity of stenosis. Stroke. 2002;33:1772–5. - PubMed
    1. Baldewsing RA, Schaar JA, Mastik F, Oomens CW, van der Steen AF. Assessment of vulnerable plaque composition by matching the deformation of a parametric plaque model to measured plaque deformation. IEEE Trans. Med. Imaging. 2005;24:514–28. - PubMed
    1. Bertrand M, Meunier M, Doucet M, Ferland G. Ultrasonic biomechanical strain gauge based on speckle tracking. IEEE Ultrasonics Symp. 1989:859–64.
    1. Bridal SL, Fornes P, Bruneval P, Berger G. Correlation of ultrasonic attenuation (30 to 50 MHz) and constituents of atherosclerotic plaque. Ultrasound Med. Biol. 1997;23:691–703. - PubMed
    1. Cespedes EI. PhD Dissertation. University of Houston; Texas: 1993. Elastography: imaging of biological tissue elasticity.

Publication types