INFLUENCE OF TISSUE PRESERVATION METHODS ON ARTERIAL GEOMETRY AND ECHOGENICITY

Thoracic porcine aortas from 5 pigs were investigated with 7,5-MHz ult rasound in vitro at low and high transmural pressure before and after the following tissue preservation methods were applied: 1, Storage in frozen condition(-12 degrees C) for 24 h followed by thawing; 2, fixat ion in formalin at zero transmural pressure for 24 h; and 3, fixation with formalin for 24 h while, applying 74 mmHg of transmural pressure from within the lumen and a tensile force to longitudinally stretch th e artery, Fixation in formalin at zero transmural pressure resulted in swelling of the arterial wall (25 +/- 40%, p < 0.02, at low transmura l measurement pressure) and in decreased echogenicity (-23 +/- 38%,p < 0.01) of the arterial vessel wall, No changes in this respect were fo und after storage in a frozen condition nor after fixation in formalin at high transmural pressure which, therefore, are more appropriate pr ocedures for fixation of arteries prior to in vitro ultrasound examina tion if geometry is important. (C) 1997 World Federation for Ultrasoun d in Medicine & Biology.