Reconstruction and Quantification of the Carotid Artery Bifurcation From 3-D Ultrasound Images

Abstract

Three-dimensional (3-D) ultrasound is a relatively new technique, which is well suited to imaging superficial blood vessels, and potentially provides a useful, noninvasive method for generating anatomically realistic 3-D models of the peripheral vasculature. Such models are essential for accurate simulation of blood flow using computational fluid dynamics (CFD), but may also be used to quantify atherosclerotic plaque more comprehensively than routine clinical methods. In this paper, we present a spline-based method for reconstructing the normal and diseased carotid artery bifurcation from images acquired using a freehand 3-D ultrasound system. The vessel wall (intima-media interface) and lumen surfaces are represented by a geometric model defined using smoothing splines. Using this coupled wall-lumen model, we demonstrate how plaque may be analyzed automatically to provide a comprehensive set of quantitative measures of size and shape, including established clinical measures, such as degree of (diameter) stenosis. The geometric accuracy of 3-D ultrasound reconstruction is assessed using pulsatile phantoms of the carotid bifurcation, and we conclude by demonstrating the in vivo application of the algorithms outlined to 3-D ultrasound scans from a series of patient carotid arteries.

A Reconstruction Method for Gappy and Noisy Arterial Flow Data

“…Consider the collection of data snapshots, , where is a vector containing the velocity field at time for all , namely the elements of are (2) These snapshots are used to compute the POD basis vectors, which yield a representation of the data that is optimal in the sense that, for any given basis size, the norm of the error is minimized. This is equivalent to solving the eigenvalue problem (3) where the eigenvectors (columns of the matrix A) represent the temporal modes, is a diagonal matrix of the eigenvalues , and C is a correlation matrix formed by computing the inner product between every pair of snapshots and (4) The magnitude of the th eigenvalue represents the relative importance of the th POD basis vector. This importance is commonly quantified by defining the relative energy content for each basis vector as (5) where the term "energy" refers to a measure in the norm.…”

“…3 In particular, MRA images of cross-sectional slices of the left CCA, ICA, and external carotid (ECA) arteries were acquired by a Genesis Signa scanner using a 3-D time-of-flight (TOF) sequence. The distance between the slices was 1.2 mm and a total of 145 images was acquired.…”

“…Recently, a new technique, 3-D US was tested as an alternative to MRA for generating anatomically realistic 3-D geometric models [3]. The geometric model data is then exported into computational fluid dynamics (CFD) codes to obtain detailed description of the blood velocity field [23], [24], [26], [30].…”

Automatic Detection of the Carotid Artery Location from Volumetric Ultrasound Images Using Anatomical Position-Dependent LBP Features

“…With conventional methods of constructing three-dimensional structures of the carotid wall, the examiner has to specify the position of the carotid artery in the ultrasound image manually [3]- [5], [9]- [11], or blood flow information is used to identify its position [12]. When the blood flow information is used to identify the carotid artery in transverse view, the examiner has to carefully place the probe to the body surface from a direction that is slightly inclined from the perpendicular to the carotid artery [13].…”

Advantages and Pitfalls of Three-Dimensional Ultrasound Imaging of Carotid Bifurcation

“…The 3D reconstruction of the carotid bifurcation from its inward flow is possible with US [30], but no papers have so far described the use of this technique in conditions different than carotid stenosis, such as bifurcation changes of the caliber and vessel course alterations. The aim of this review was to explore the possibility of visualizing the carotid bifurcation with 3D US reconstructions from the inward flow in several conditions: in normal subjects, in subjects with caliber alterations (carotid bulb ectasia and internal carotid artery caliber narrowing) and vessel course modifications (tortuosities and kinking).…”