A Novel Semiautomated Atherosclerotic Plaque Characterization Method Using Grayscale Intravascular Ultrasound Images: Comparison With Virtual Histology

Abstract

Intravascular ultrasound (IVUS) virtual histology (VH-IVUS) is a new technique, which provides automated plaque characterization in IVUS frames, using the ultrasound backscattered RF-signals. However, its computation can only be performed once per cardiac cycle (ECG-gated technique), which significantly decreases the number of characterized IVUS frames. Also atherosclerotic plaques in images that have been acquired by machines, which are not equipped with the VH software, cannot be characterized. To address these limitations, we have developed a plaque characterization technique that can be applied in grayscale IVUS images. Our semiautomated method is based on a three-step approach. In the first step, the plaque area [region of interest (ROI)] is detected semiautomatically. In the second step, a set of features is extracted for each pixel of the ROI and in the third step, a random forest classifier is used to classify these pixels into four classes: dense calcium, necrotic core, fibrotic tissue, and fibro-fatty tissue. In order to train and validate our method, we used 300 IVUS frames acquired from virtual histology examinations from ten patients. The overall accuracy of the proposed method was 85.65% suggesting that our approach is reliable and may be further investigated in the clinical and research arena.

Automatic Detection of Dense Calcium and Acoustic Shadow in Intravascular Ultrasound Images by Dual-threshold-based Segmentation Approach

“…Typically, the mean intensities of arterial tissues are in the order of DC > NC > FT > FFT in IVUS sequences. (15,21) Moreover, the overlapping region between FFT and DC is quite small because these tissues have quite different intensity profiles. Existing approaches have attempted to classify tissue compositions on the basis of these characteristics and verified that the intensity could be a good indicator for tissue characterization.…”

Segmentation and Reconstruction Techniques for Modeling of Blood Vessel

“…IVUS viz., Intravascular Ultrasound (non invasive) technique is better than CTA (invasive) is explained in [22]. Canny operator is used for edge detection and using Hough Transform arterial walls are extracted.…”

Stent Deployment Computer Based Simulations for Health Care Treatment of Diseased Arteries

“…A specific algorithm was used to represent the luminal and media adventitia point clouds by placing the 2D detected lumen and media-adventitia borders on the 3D catheter path. As far as the 3D reconstructed characterized plaque is concerned, the methodology introduced by Athanasiou et al (2012) was employed. This semiautomated methodology mainly consists of three phases.…”