Evaluating the regional elastic modulus of a cylindrical shell with nonuniform wall thickness

Hasegawa, Hideyuki; Kanai, Hiroshi; Hoshimiya, Nozomu; Koiwa, Yoshiro

doi:10.1007/s10396-004-0014-y

Cited by 49 publications

(49 citation statements)

References 9 publications

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“…DISCUSSION The estimation of stress distribution in the arterial wall is one of the most difficult problems. In our study [6], the stress distribution in the arterial wall was assumed to be constant. Even in the case of a homogeneous cylindrical shell, the stress (strain) distribution is dependent on the distance from luminal surface.…”

Section: Basic Experimental Resultsmentioning

confidence: 99%

Strain Imaging of Arterial Wall with Reduction of Effects of Variation in Center Frequency of Ultrasonic RF Echo

Hasegawa

Kanai

2009

IFMBE Proceedings

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Abstract-Atherosclerotic change of the arterial wall leads to a significant change in its elasticity. For assessment of elasticity, measurement of arterial wall deformation is required. For motion estimation, correlation techniques are widely used, and we developed a phase-sensitive correlation method, namely, the phased-tracking method, to measure the regional strain of the arterial wall due to the heartbeat. Although phasesensitive methods using demodulated complex signals require less computation in comparison with methods using the correlation between RF signals or iterative methods, the displacement estimated by such phase-sensitive methods are biased when the center frequency of the RF echo apparently varies. One of the reasons for the apparent change in the center frequency would be the interference of echoes from scatterers within the wall. In the present study, a method was introduced to reduce the influence of variation in the center frequencies of RF echoes on the estimation of the artery-wall strain when using the phase-sensitive correlation technique. The improvement in the strain estimation by the proposed method was validated using a phantom. The error from the theoretical strain profile and the standard deviation in strain estimated by the proposed method were 12.0% and 14.1%, respectively, significantly smaller than those (23.7% and 46.2%) obtained by the conventional phase-sensitive correlation method. Furthermore, in the preliminary in vitro experimental results, the strain distribution of the arterial wall well corresponded with pathology, i.e., the region with calcified tissue showed very small strain, and the region almost homogeneously composed of smooth muscle and collagen showed relatively larger strain and clear strain decay with respect to the radial distance from the lumen.

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Section: Basic Experimental Resultsmentioning

confidence: 99%

Strain Imaging of Arterial Wall with Reduction of Effects of Variation in Center Frequency of Ultrasonic RF Echo

Hasegawa

Kanai

2009

IFMBE Proceedings

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“…The distribution of elasticity is displayed as a 2D cross-sectional color image on B-mode images, and the image is updated every heartbeat. For the measurement of minute changes in thickness, the system uses the phased tracking method [5][6][7][8][9][10] . The elasticity parameter was estimated at intervals of 80 m in the depth direction and 400 m in the axial direction.…”

Section: Carotid Imt and Elasticity Measurementsmentioning

confidence: 99%

“…Circumferential stress acting on the cylindrical shell is not the same as pulse pressure and also depends on r0/h0; therefore, Er is apparent elasticity in the radial direction and depends on r0/h0 as well as on the elasticity of the arterial wall. Alternatively, E was introduced to evaluate the elasticity of the arterial wall by suppressing the influence of r0/h0 7) . The measurement reproducibility has been reported previously 11) .…”

Section: Carotid Imt and Elasticity Measurementsmentioning

confidence: 99%

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Impact of Lifestyle-Related Diseases on Carotid Arterial Wall Elasticity as Evaluated by an Ultrasonic Phased-Tracking Method in Japanese Subjects

Yamagishi

Katô

Koiwa³

et al. 2009

JAT

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Aim:We investigated the relationship between coronary risk factors and the intima-media thickness (IMT) and wall elasticity of carotid arteries. A new real-time ultrasonic measurement system that allows measurement of the elasticity of the carotid arterial intima-media complex was applied to 350 subjects, who were also checked for the presence/absence of hypertension, dyslipidemia, diabetes mellitus and regular smoking. Simultaneous measurement of the elastic modulus and IMT was conducted at four sites in the bilateral carotid arteries.

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“…The distribution of elasticity is displayed as a 2D cross-sectional color-coded image in B-mode imaging, and the image is updated at every heartbeat. To measure minute changes in thickness during one cardiac cycle, this system uses the phased tracking method [5][6][7][8][9][10] . Elasticity was estimated at intervals of 80 m along each ultrasonic beam in the depth direction and 400 m in the arterial longitudinal direction.…”

Section: Carotid Imt and Elasticity Measurementsmentioning

confidence: 99%

Evaluation of Plaque Stabilization by Fluvastatin with Carotid Intima- Medial Elasticity Measured by a Transcutaneous Ultrasonic-Based Tissue Characterization System

Yamagishi

Katô

Koiwa³

et al. 2009

JAT

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Aim:As an approach to tissue characterization, we attempted to classify in vivo carotid plaque tissues in terms of arterial wall elasticity instead of echogenicity on B-mode scanning and investigated whether the effect of fluvastatin on carotid elasticity can be detected in hypercholesterolemic patients. Methods: In 170 subjects, simultaneous measurements of intima-media thickness (IMT) and elastic modulus in the circumferential direction (E ) were performed using a new transcutaneous high-resolution Doppler technique.

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Evaluating the regional elastic modulus of a cylindrical shell with nonuniform wall thickness

Abstract: In basic experiments employing silicone rubber tubes with nonuniform wall thickness as arterial models, the elastic moduli of silicone rubber tubes were evaluated by measuring changes in wall thickness. These results confirm the value of the proposed method.

Cited by 49 publications

References 9 publications

Strain Imaging of Arterial Wall with Reduction of Effects of Variation in Center Frequency of Ultrasonic RF Echo

Strain Imaging of Arterial Wall with Reduction of Effects of Variation in Center Frequency of Ultrasonic RF Echo

Impact of Lifestyle-Related Diseases on Carotid Arterial Wall Elasticity as Evaluated by an Ultrasonic Phased-Tracking Method in Japanese Subjects

Evaluation of Plaque Stabilization by Fluvastatin with Carotid Intima- Medial Elasticity Measured by a Transcutaneous Ultrasonic-Based Tissue Characterization System

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