Three-dimensional imaging and computational modelling for estimation of wall stresses in arteries

The paper reviews techniques for the estimation of wall stresses in arterial disease. Wall stresses are important as arterial disease progresses through a complex interplay between local biology and local mechanical stresses. The possibility then arises of using wall stresses as new diagnostic indicators in patients with arterial disease. Estimation of wall stresses using imaging systems is problematic. Developments in the last 10 years have been aimed at providing tools for estimation of wall stresses within individual patients, using a combination of three-dimensional (3D) imaging and computational modelling. For blood flow, 3D arterial lumen information is obtained from 3D imaging. Computational fluid dynamics is then used to estimate the 3D velocity field within the lumen, from which wall shear stress may be calculated. For arterial mechanics, the 3D arterial wall geometry is integrated with solid modelling to provide estimates of the strain field and stress field within the artery wall. For intraplaque stresses, this has been achieved through the use of detailed two-dimensional (2D) intraplaque geometry from MRI. Inverse techniques have been used to provide images of Young's modulus in atherosclerotic plaque using intravascular ultrasound and solid modelling. Several research centres now have processing chains to allow this technology to be used in clinical studies. In time, possibly over the next 10 years or so, robust protocols with proven clinical utility will arise which, when combined with high-performance computing, will allow image-guided modelling to be used as an adjunct to modern radiology in the same way that image-processing tools are used today.