A video-optical system for time-resolved whole-body measurement on vascular segments

This paper presents a novel experimental setup to get the three-dimensional (3-D) whole-body deformation of arterial segments under finite inflation and extension. A simple one camera/one shot arrangement allows non-contacting, full-field, real-time measurements to be performed. A concave conical mirror mounted coaxially to the camera provides the whole 360 degrees field view of a large number of closely spaced micro-spheres affixed to the sample surface. Then, on the basis of radial metrology concepts, each single frame of the loading sequence is automatically processed to track 3-D marker positions and, thus, to obtain sample deformation at the camera frame acquisition rate. Preliminary tests are run to evaluate measurement accuracy and to calibrate the system for in-vitro testing in physiological solution. Then, pressure-diameter tests at various levels of axial extension are performed on an excised porcine arterial segment using a specially designed in-vitro rig. Experimental data demonstrate that the present method can provide either global parameters to be used within standard constitutive frameworks and important full-field information on the eventual inhomogeneity of deformation. To better illustrate the latter achievement, results related to the 'bend buckling' of a straight porcine vascular vessel tested at low axial stretch are reported. Remarkably, the experimental apparatus can be adapted to a large variety of test protocols and sample geometries. (C) 2009 Elsevier Ltd. All rights reserved.