Modulography: elasticity imaging of atherosclerotic plaques

Modulography is an experimental elasticity imaging method. It has potential to become an all-in-one in vivo tool (a) for detecting vulnerable atherosclerotic coronary plaques, (b) for assessing information related to their rupture-proneness and (c) for imaging their elastic material composition. Modulography determines a cross-sectional image of the elasticity distribution (=Young's modulus) from deformation (=strain) that is processed from intravascular ultrasound (IVUS) measurements. By looking at this image, cardiologists and other researchers can directly identify and characterize soft and stiff plaque-components of thin-cap fibroatheromas and of heterogeneous plaques. As a diagnostic and pharm

Intravascular palpography for high-risk vulnerable plaque assessment.

Item does not contain fulltextBACKGROUND: The composition of an atherosclerotic plaque is considered more important than the degree of stenosis. An unstable lesion may rupture and cause an acute thrombotic reaction. Most of these lesions contain a large lipid pool covered by an inflamed thin fibrous cap. The stress in the cap increases with decreasing cap thickness and increasing macrophage infiltration. Intravascular ultrasound (IVUS) palpography might be an ideal technique to assess the mechanical properties of high-risk plaques. TECHNIQUE: Palpography assesses the local mechanical properties of tissue using its deformation caused by the intraluminal pressure. IN VITRO VALIDATION: The technique was validated in vitro using diseased human coronary and femoral arteries. Especially between fibrous and fatty tissue, a highly significant difference in strain (p = 0.0012) was found. Additionally, the predictive value to identify the vulnerable plaque was investigated. A high-strain region at the lumen-vessel wall boundary has an 88% sensitivity and 89% specificity for identifying such plaques. IN VIVO VALIDATION: In vivo, the technique was validated in an atherosclerotic Yucatan minipig animal model. This study also revealed higher strain values in fatty than fibrous plaques (p < 0.001). The presence of a high-strain region at the lumenplaque interface has a high predictive value to identify macrophages. PATIENT STUDIES: Patient studies revealed high-strain values (1-2%) in thin-cap fibrous atheroma. Calcified material showed low strain values (0-0.2%). With the development of three-dimensional (3-D) palpography, identification of highstrain spots over the full length of a coronary artery becomes available. CONCLUSION: Intravascular palpography is a unique tool to assess lesion composition and vulnerability. The development of 3-D palpography provides a technique that may develop into a clinical tool to identify the high-risk plaque

Resonant acoustic radiation force optical coherence elastography.

We report on a resonant acoustic radiation force optical coherence elastography (ARF-OCE) technique that uses mechanical resonant frequency to characterize and identify tissues of different types. The linear dependency of the resonant frequency on the square root of Young's modulus was validated on silicone phantoms. Both the frequency response spectrum and the 3D imaging results from the agar phantoms with hard inclusions confirmed the feasibility of deploying the resonant frequency as a mechanical contrast for tissue imaging. Furthermore, the results of resonant ARF-OCE imaging of a post-mortem human coronary artery with atherosclerosis demonstrate the potential of the resonant ARF-OCE as a non-invasive method for imaging and characterizing vulnerable plaques