A fibroatheroma is a combination of a fibrous cap (arrows) and a necrotic core (asterisks). A fibrous cap is a signal-rich tissue layer overlaying a signal-poor region. The necrotic core is a signal-poor region within an atherosclerotic plaque with poorly delineated borders, a rapid signal drop-off and little or no signal backscattering within a lesion that is covered by a fibrous cap. It is imperative to note the distinction between signal-poor regions of calcium which have sharply delineated borders and signal-poor regions of necrotic core which have poorly defined borders.