sup 18^F-FDG PET Guided Histological Analysis on Adhesive Molecules in a Rat Model of Acute Myocarditis

Objectives: Serial non-invasive imaging would provide better understanding of dynamic process of acute autoimmune myocarditis. The aim of this study is to elucidate the time course of cellular expression of adhesion molecules in acute myocarditis in association with the prior inflammatory activities identified by serial non-invasive 18F-FDG imaging. Methods: Autoimmune myocarditis was induced in Lewis rats by immunizing with porcine cardiac myosin emulsified in complete Freund's adjuvant. First, serial 18F-FDG PET imaging (2,3,4,5 and 10 weeks after immunization) was performed to determine the time course and feasibility of monitoring acute cardiac inflammation. Next, based on the individual results of serial 18F-FDG imaging, animals were assigned for three inflammatory stages: acute inflammation (Gr-0W) as well as 2 weeks (Gr-2W) and 7 weeks (Gr-7W) after the peak of acute inflammation, respectively. Histological analysis at each stages was conducted for adhesion markers (CD44 and CD34). Results: Serial 18F-FDG PET imaging revealed focal and temporal increased tracer uptake in the heart peaked at around week 3 in average and decreased rapidly. Localization of CD68 positive cell infiltrations and 18F-FDG uptake signals were well correlated (R=0.91, P