Introduction to magnetic resonance imaging

Abstract

The uniqueness of MR images lies in the physical origin of the signal. In X-rays, the radiation (X) is “absorbed” more by bones and less by soft tissues. Consequently, in X-rays (negative), bones appear as the bright part of the image, whereas soft tissues are darker. The same applies to ultrasonography. Ultrasounds cross the tissues and are absorbed by them in differing degrees. The resulting image reflects the different level of ultrasound absorption by the tissues. In both cases, the image results from the interaction between the X radiation or ultrasounds and the electronic structure of matter.