A general solution for catheter position effects for strain estimation in intravascular elastography

Shi, Hu; Chen, Quan; Varghese, Tomy

doi:10.1016/j.ultrasmedbio.2005.07.004

Cited by 11 publications

(5 citation statements)

References 30 publications

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“…shapo et al derived a closed-form analytical expression to compute the true tissue displacement, taking into account the dislocation of the catheter, and validated the method on a tissue-mimicking phantom. similarly, de Korte [26], Perrey [27], and H. shi [28] obtained a general formula for strain projection artifacts caused by the eccentric position of the iVus probe within the luminal cavity and corroborated their theory on a tissue mimicking phantom. shi et al [29] emphasized the necessity to compensate for bulk tissue motion in thermal elastographic imaging.…”

Section: Improving Ivus Palpography By Incorporation Of Motion Compenmentioning

confidence: 68%

Improving IVUS palpography by incorporation of motion compensation based on block matching and optical flow

Danilouchkine

Mastik

Steen

2008

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Intravascular ultrasound (IVUS) strain imaging of the luminal layer in coronary arteries, coined as IVUS palpography, utilizes conventional radio frequency (RF) signals acquired at 2 different levels of a compressional load. The signals are cross-correlated to obtain the microscopic tissue displacements, which can be directly translated into local strain of the vessel wall. However, (apparent) tissue motion and nonuniform deformation of the vessel wall, due to catheter wiggling, reduce signal correlation and result in invalid strain estimates. Implications of probe motion were studied on the tissue-mimicking phantom. The measured circumferential tissue displacement and level of the speckle decorrelation amounted to 12 degrees and 0.58, respectively, for the catheter displacement of 456 microm. To compensate for the motion artifacts in IVUS palpography, a novel method based on the feature-based scale-space optical flow (OF), and classical block matching (BM) algorithm, were employed. The computed OF vector and BM displacement fields quantify the amount of local tissue misalignment in consecutive frames. Subsequently, the extracted circumferential displacements are used to realign the signals before strain computation. Motion compensation reduces the RF signal decorrelation and increases the number of valid strain estimates. The advantage of applying the motion correction in IVUS palpography was demonstrated in a midscale validation study on 14 in vivo pullbacks. Both methods substantially increase the number of valid strain estimates in the partial and compounded palpograms. Mean relative improvement in the number of valid strain estimates with motion compensation in comparison to one without motion compensation amounts to 28% and 14%, respectively. Implementation of motion compensation methods boosts the diagnostic value of IVUS palpography.

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Section: Improving Ivus Palpography By Incorporation Of Motion Compenmentioning

confidence: 68%

Improving IVUS palpography by incorporation of motion compensation based on block matching and optical flow

Danilouchkine

Mastik

Steen

2008

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…IVUSE technique based on radiofrequency signal processing gives better resolution and accuracy than that based on digital B-mode analysis, but the former must take into account issues such as angle matching and signal compensation caused by the eccentric position of the AUC area under the receiver operating characteristic curve, CI confidential interval IVUS catheter and the complexity of equipment [7,21,22]. As well, the compatible and portable features of digital B-mode analysis make it advantageous for rapid construction of IVUSE off-or on-line to acquire elastic profiles of tissue and characterize atherosclerotic plaque components.…”

Section: Discussionmentioning

confidence: 99%

Atherosclerotic plaque components characterization and macrophage infiltration identification by intravascular ultrasound elastography based on b-mode analysis: validation in vivo

Zhang

et al. 2010

Int J Cardiovasc Imaging

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Intravascular ultrasound elastography (IVUSE) is a promising imaging technique for early investigation of vulnerable plaques. Compared to radiofrequency signal processing, digital B-mode analysis is simple and of higher portability. However, rare studies have been reported validating the latter technique in vivo. In this study, we developed an IVUSE computer software system involving semi-automatic border delineation and block-matching algorithm and validated the system in vivo. Seven minipigs were fed with atherogenic diet for 40 weeks. For each pig, the endothelium of one side of the renal arteries was denuded at the fifth week. With cross-correlation analysis, Lagrangian strain was calculated from two intravascular ultrasound images acquired in situ. Sixty regions of interests were selected from 35 elastograms matched well with the corresponding histological slices. Plaque types within these regions were classified as fibrous, fibro-fatty or fatty on Masson's trichrome and Oil-red O staining. Macrophage infiltration was also evaluated with immunohistology. Comparison between the mean strain value of the region of interest and the histological results revealed significant differences in strain values among different plaque types and non-diseased artery walls. The extent of macrophage infiltration was found to be correlated positively with strain values. For identification of fibro-fatty and fibrous plaques and macrophage infiltration, the system showed high sensitivity (93, 96 and 92%, respectively) and specificity (89, 76 and 66%, respectively), as revealed by receiver operating characteristic analysis. Our IVUSE system based on B-mode analysis is capable of characterizing fibrous and fibro-fatty plaques and macrophage intensity, thus holds potential for identifying vulnerable plaque.

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“…For example, the angular dependence of insonification and reverberation artifacts makes IVUS images difficult to interpret, and the increased frequency-dependent attenuation slope (with higher center frequencies) reduces signal penetration in some cases. Moreover, catheter position artifacts also introduce strain estimation errors (Shi et al 2005). These problems affect the accuracy of the displacement and strain estimations performed.…”

Section: Introductionmentioning

confidence: 99%

Preliminaryin vivoatherosclerotic carotid plaque characterization using the accumulated axial strain and relative lateral shift strain indices

et al. 2008

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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 microemboli 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.

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A general solution for catheter position effects for strain estimation in intravascular elastography

Cited by 11 publications

References 30 publications

Improving IVUS palpography by incorporation of motion compensation based on block matching and optical flow

Improving IVUS palpography by incorporation of motion compensation based on block matching and optical flow

Atherosclerotic plaque components characterization and macrophage infiltration identification by intravascular ultrasound elastography based on b-mode analysis: validation in vivo

Preliminaryin vivoatherosclerotic carotid plaque characterization using the accumulated axial strain and relative lateral shift strain indices

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