ABSTRACT
The principle of nuclear magnetic resonance was first described in 1946 (1,2). A radiofrequency (RF) applied to a sensitive nucleus in the setting of a magnetic field can induce resonance ultimately resulting in a signal at a frequency that is related to the chemical and structural properties of the molecules that contain the sensitive nuclei. Different molecules and different environments of these molecules can change the frequencies of the signals emitted, allowing differentiation between nuclear species and their environments. The mathematical operation of Fourier transformation provides a means of changing the distribution of frequencies (in k-space) into spectra. A spectrum is a two-dimensional representation of the frequencies of the signals depicting the various molecular components containing the sensitive nucleus under scrutiny (Fig. 1). The magnitude of the spectral peaks (the area under the peak at each frequency) represents the concentration of the molecule being sampled in the myocardium (for example).
