Influence of the accuracy of angiography-based reconstructions on velocity and wall shear stress computations in coronary bifurcations: A phantom study

Wall shear stress (WSS) plays a key role in the onset and progression of atherosclerosis in human coronary arteries. Especially sites with low and oscillating WSS near bifurcations have a higher propensity to develop atherosclerosis. WSS computations in coronary bifurcations can be performed in angiography-based 3D reconstructions. It is...

A computer-simulation study on the effects of MRI voxel dimensions on carotid plaque lipid-core and fibrous cap segmentation and stress modeling

Background The benefits of a decreased slice thickness and/or in-plane voxel size in carotid MRI for atherosclerotic plaque component quantification accuracy and biomechanical peak cap stress analysis have not yet been investigated in detail because of practical limitations. Methods In order to provide a methodology that allows such an...

Photoacoustic imaging of carotid artery atherosclerosis

We introduce a method for photoacoustic imaging of the carotid artery, tailored toward detection of lipid-rich atherosclerotic lesions. A common human carotid artery was obtained at autopsy, embedded in a neck mimicking phantom and imaged with a multimodality imaging system using interstitial illumination. Light was delivered through a 1.25-mm...

Atherosclerotic plaque fibrous cap assessment under an oblique scan plane orientation in carotid MRI

Carotid magnetic resonance imaging (MRI) is used to noninvasively assess atherosclerotic plaque fibrous cap (FC) status, which is closely related to ischemic stroke. Acquiring anisotropic voxels improves in-plane visualization, however, an oblique scan plane orientation could then obscure a FC (i.e., contrast below the noise level) and thus...

Intravascular Photoacoustic Imaging: A New Tool for Vulnerable Plaque Identification

The vulnerable atherosclerotic plaque is believed to be at the root of the majority of acute coronary events. Even though the exact origins of plaque vulnerability remain elusive, the thin-cap fibroatheroma, characterized by a lipid-rich necrotic core covered by a thin fibrous cap, is considered to be the most prominent type of vulnerable plaque...

Mapping Intravascular Ultrasound Controversies in Interventional Cardiology Practice

Intravascular ultrasound is a catheter-based imaging modality that was developed to investigate the condition of coronary arteries and assess the vulnerability of coronary atherosclerotic plaques in particular. Since its introduction in the clinic 20 years ago, use of intravascular ultrasound innovation has been relatively limited. Intravascular...

Effect of temperature and fixation on the optical properties of atherosclerotic tissue: A validation study of an ex-vivo whole heart cadaveric model

Atherosclerotic plaque composition can be imaged using the optical attenuation coefficient derived from intravascular optical coherence tomography (OCT) data. The relation between optical properties and tissue type has been established on autopsy tissues. In this study, we validate an ex-vivo model for the effect of temperature and tissue...

Photoacoustic imaging of human coronary atherosclerosis in two spectral bands

Spectroscopic intravascular photoacoustic imaging (sIVPA) has shown promise to detect and distinguish lipids in atherosclerotic plaques. sIVPA generally utilizes one of the two high absorption bands in the lipid absorption spectrum at 1.2 ?m and 1.7 ?m. Specific absorption signatures of various lipid compounds within the bands in either...

Spectroscopic intravascular photoacoustic imaging of lipids in atherosclerosis

The natural history of atherosclerosis is marked by changes in the lipid biochemistry in the diseased arterial wall. As lesions become more vulnerable, different cholesterol species accumulate in the plaque. Understanding unstable atherosclerosis as a pharmacological and interventional therapeutic target requires chemically specific imaging of...

Lipid detection in atherosclerotic human coronaries by spectroscopic intravascular photoacoustic imaging

The presence of lipids in atherosclerotic coronary lesions is an important determinant of their potential to trigger acute coronary events. Spectroscopic intravascular photoacoustic imaging (sIVPA) has the potential to automatically detect lipids in atherosclerotic lesions. For realtime in vivo imaging, limiting the number of excitation...

Intravascular ultrasound chirp imaging

We demonstrate the feasibility of intravascular ultrasound (IVUS) chirp imaging as well as chirp reversal ultrasound contrast imaging at intravascular ultrasound frequency. Chirp excitations were emitted with a 34?MHz single crystal intravascular transducer and compared to conventional Gaussian-shaped pulses of equal acoustic pressure. The...

Comparison of fundamental, second harmonic, and superharmonic imaging: A simulation study

In medical ultrasound, fundamental imaging (FI) uses the reflected echoes from the same spectral band as that of the emitted pulse. The transmission frequency determines the trade-off between penetration depth and spatial resolution. Tissue harmonic imaging (THI) employs the second harmonic of the emitted frequency band to construct images....

Effects of intima stiffness and plaque morphology on peak cap stress

Background: Rupture of the cap of a vulnerable plaque present in a coronary vessel may cause myocardial infarction and death. Cap rupture occurs when the peak cap stress exceeds the cap strength. The mechanical stress within a cap depends on the plaque morphology and the material characteristics of the plaque components. A parametric study was...