Ultrasound tissue displacement imaging with application to breast cancer

Chen, E. J.; Adler, Ronald S.; Carson, Paul L.; Jenkins, W.K.; O’Brien, William D.

doi:10.1016/0301-5629(95)02005-5

Cited by 59 publications

(38 citation statements)

References 25 publications

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“…by changing its permeability, by increasing the adhesiveness of the endothelium to leukocytes, and by inducing endothelial expression of vasoactive molecules favoring arterial stiffening and increased IMT (Ross, 1999). Thus, reduced FMD identifies abnormalities of endothelial function preceding the development of a structural lesion, and IMT indicates the presence of vascular damage, suggestive of a more advanced stage of AS (Chen et al, 1995). It is essential to recognize early arterial changes in the both functional and structural changes terms, to inhibit progress of AS.…”

Section: Discussionmentioning

confidence: 99%

Pitavastatin calcium improves endothelial function and delays the progress of atherosclerosis in patients with hypercholesterolemia

Zhao

Yan

et al. 2015

J. Zhejiang Univ. Sci. B

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Background: Statins have proven efficacy in inhibiting the onset and progress of atherosclerosis. The effectiveness of pitavastatin in reversing carotid atherosclerosis associated with hypercholesterolemia (HC) is unknown. Objectives: To explore the simultaneous effects of pitavastatin calcium on brachial arterial flow-mediated vasodilatation (FMD), carotid intima-media thickness (IMT), and arterial stiffness (β), three surrogate markers of atherosclerosis were studied in HC patients. Methods: A randomized, double-blind trial was performed with 40 HC subjects who fulfilled the inclusion/exclusion criteria. Patients were given pitavastatin calcium 1 mg/d (Group 1) or 2 mg/d (Group 2) for 8 weeks. There were 20 patients in each group, and 30 gender-and age-matched healthy subjects as controls were recruited. FMD of the brachial artery, carotid IMT, and arterial stiffness indicated by β were measured at baseline and at 8 weeks after starting pitavastatin calcium therapy using ultrasound techniques. Biochemical tests were also made on all subjects. Results: At baseline, higher total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C), reduced FMD, and increased β and IMT were observed in HC patients (P<0.001 for all) compared with controls. After 8 weeks, TC was decreased by 20.59%/27.56% and LDL-C 30.92%/35.64%, respectively, in comparison to baseline groups; the HC groups had reduced β and improved endothelial function over the 8-week follow-up (P<0.05-0.001); nonetheless, no significant alterations of IMT were found (P>0.05). Significant negative interactions between TC/LDL and FMD (P<0.05-0.001), positive interactions between TC and IMT (P=0.003) and between TC/LDL and β (P<0.001-0.000) were found. Conclusions: Treatment with pitavastatin calcium exerted favorable effects on endothelial function and arterial stiffness. It also improved carotid atherosclerosis in patients with HC.

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Section: Discussionmentioning

confidence: 99%

Pitavastatin calcium improves endothelial function and delays the progress of atherosclerosis in patients with hypercholesterolemia

Zhao

Yan

et al. 2015

J. Zhejiang Univ. Sci. B

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“…Elastography or techniques that image the local stiffness properties of tissue is a relatively new technique for noninvasive investigation of tissue mechanical properties (Ophir et al 1991;Cespedes et al 1993;O'Donnell et al 1994;Talhami et al 1994;Chen et al 1995;Bilgen and Insana 1996;Zhu and Hall 2002). In elastography local strains are obtained by computing the gradient of the displacement field along the axial direction between the pre-and postcompression echo signal frames obtained after a quasistatic compression.…”

Section: Introductionmentioning

confidence: 99%

Improvement of elastographic displacement estimation using a two-step cross-correlation method

Chen

Shi

Varghese

2007

Ultrasound in Medicine & Biology

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The cross-correlation algorithm used to compute the local strain components for elastographic imaging requires a minimum radio-frequency data segment length of around 10 wavelengths to obtain accurate and precise strain estimates with a reasonable signal-to-noise ratio. Shorter radio-frequency data segments generally introduce increased estimation errors as the information content in the data segment reduces. However, shorter data segments and increased overlaps are essential to improve the axial resolution in the strain image. In this paper, we propose a two-step cross-correlation technique that enables the use of window lengths on the order of a single wavelength to provide displacement and strain estimates with similar noise properties as those obtained with a 10 wavelength window. The first processing step utilizes a window length on the order of 10 wavelengths to obtain coarse displacement estimates between the pre-and postcompression radio frequency data frames. This coarse displacement is then interpolated and utilized as the initial guessestimate for the second cross-correlation processing step using the smaller window. This step utilizes a single wavelength window to improve the axial resolution in strain estimation, without significantly compromising the noise properties of the image. Simulation and experimental results show that the signal-to-noise and contrast-to-noise ratio estimates improve significantly at the smaller window lengths with the two-step processing when compared with the use of a similar sized window in the currently utilized single window method.

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“…Elastography or elasticity imaging has developed into an imaging modality for the diagnosis of abnormalities in the breast, prostate, thyroid, liver and kidneys, as well as for intravascular atherosclerotic plaque characterization applications (Parker et al 1990;Ophir et al 1991;O'Donnell et al 1994;Chen et al 1995;Bamber and Bush 1996;de Korte et al 2000;Pesavento et al 2000;Insana et al 2001;Nightingale et al 2001;Varghese et al 2001). Elastography also enhances the capability for imaging and monitoring thermal ablative therapies for cancer treatment in organs such as the liver, kidney and prostate that are not clearly visualized under conventional ultrasound (US) imaging (Stafford et al 1998;Righetti et al 1999;Varghese et al 2002Varghese et al , 2003Souchon et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Improvements in elastographic contrast-to-noise ratio using spatial-angular compounding

Techavipoo¹,

Varghese²

2005

Ultrasound in Medicine & Biology

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Spatial-angular compounding is a new technique developed for improving the signal-to-noise ratio (SNR) in elastography. Under this method, elastograms of a region-of-interest (ROI) are obtained from a spatially weighted average of local strain estimated along different insonification angles. In this article, we investigate the improvements in the strain contrast and contrast-to-noise ratio (CNR) of the spatially compounded elastograms. Spatial angular compounding is also applied and evaluated in conjunction with global temporal stretching. Quantitative experimental results obtained using a single-inclusion tissue-mimicking phantom demonstrate that the strain contrast reduces slightly but the CNR improves by around 8 to 13 dB. We also present experimental spatial angular compounding results obtained from an in vitro thermal lesion in canine liver tissue embedded in a gelatin phantom that demonstrate the improved visual characteristics (due to the improved CNR) of the compound elastogram. The experimental results provide guidelines for the practical range of maximum insonification angles and estimates of the optimum angular increment.

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Ultrasound tissue displacement imaging with application to breast cancer

Cited by 59 publications

References 25 publications

Pitavastatin calcium improves endothelial function and delays the progress of atherosclerosis in patients with hypercholesterolemia

Pitavastatin calcium improves endothelial function and delays the progress of atherosclerosis in patients with hypercholesterolemia

Improvement of elastographic displacement estimation using a two-step cross-correlation method

Improvements in elastographic contrast-to-noise ratio using spatial-angular compounding

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