Myocardial scarring is the accumulation of fibrosis tissue resulting after some form of trauma to the cardiac tissue. Fibrosis is the formation of excess tissue in replacement of necrotic or extensively damaged tissue. Fibrosis in the heart is often hard to detect because fibromas are often formed. Fibromas are scar tissue or small tumors, formed in one cell line. Because they are so small they can be hard to detect by methods such as magnetic resonance imaging. A cell line is a path of fibrosis that follow only a line of cells.