Magnetic resonance imaging: a brief review of image contrast.

Because MRI is sensitive to tissue properties that are quite different from those exploited by traditional x-ray technologies, it has provided a highly sensitive new way of looking at the human body. This article summarizes the basic mechanisms of contrast in proton MR images, examining the phenomena responsible and the user's ability to manipulate contrast through system parameters. The intended purpose is to impart a qualitative, intuitive understanding of these mechanisms to the newer user.