Blowing Up the Stiff Balloon: X-Ray Microtomography Reveals Decrease in Arterial Distensibility in Pulmonary Hypertension

Abstract

We are developing nondestructive and non-traumatic imaging methods to quantitatively assess structural and mechanical properties of vascular trees and other complex biological systems. We are applying these methods to studies of vascular remodeling in rodent models of disease. Quantitative vascular tree morphometry has, in the past, been carried out using corrosion casting methods which supply valuable information, but are destructive and tend to be tedious, in particular with regard to associating vessel segment measurements accurately with their positions in the intact tree hierarchy. One of our goals is to refine imaging methods capable of quantifying mechanical, as well as anatomical properties, by virtue of their ability to rapidly acquire multiple image volumes of the same structure under various conditions, all in a nearphysiological state.Using the micro-CT scanner shown in Figure 1, consisting of a microfocal x-ray tube, specimen stage and image intensifier coupled to a 10242, 12-bit CCD camera, we acquire magnified (3-9X), transmitted x-ray projections of contrast enhanced, excised rat lungs or lung lobes.