Automatic Detection of Regional Heart Rejection in USPIO-Enhanced MRI

Contrast-enhanced magnetic resonance imaging (MRI) is useful to study the infiltration of cells in vivo. This research adopts ultrasmall superparamagnetic iron oxide (USPIO) particles as contrast agents. USPIO particles administered intravenously can be endocytosed by circulating immune cells, in particular, macrophages. Hence, macrophages are labeled with USPIO particles. When a transplanted heart undergoes rejection, immune cells will infiltrate the allograft. Imaged by T 2-weighted MRI, USPIOlabeled macrophages display dark pixel intensities. Detecting these labeled cells in the image facilitates the identification of acute heart rejection. This paper develops a classifier to detect the presence of USPIO-labeled macrophages in the myocardium in the framework of spectral graph theory. First, we describe a USPIO-enhanced heart image with a graph. Classification becomes equivalent to partitioning the graph into two disjoint subgraphs. We use the Cheeger constant of the graph as an obj...

• Type: Journal
• Year: 2008
• Where: TMI
• Authors: Hsun-Hsien Chang, José M. F. Moura, Yijen L. Wu, Chien Ho
• Keywords: Immune Cells, Macrophages, TMI 2008, Ultrasmall Superparamagnetic Iron Oxide