Image Contrast: T1, T2, T2*, and Proton Density

Abstract

We began our discussion in Chapter 1 with the concept of contrast resolution:

The MRI acquisition must elicit a different signal from each of the tissues we wish to separate. If we do not meet this requirement, our images will be incapable of demonstrating a difference between normal and abnormal and will be essentially useless. We generate image contrast by exploiting differences between tissues in their behavior within the magnetic field. Specifically, differences in proton density, T1, T2, and T2* can be enhanced or minimized by our choice of the parameters used in generating and sampling the signal. In this chapter, we will examine the contrast modulation by the parameters TE and TR. Other means for modulating contrast include (but are certainly not limited to) flip angle and TI These will be presented later in Chapters 8 and 12.