Titlebook: Clinical MR Imaging and Physics; A Tutorial Haris S. Chrysikopoulos Book 2009 Springer-Verlag Berlin Heidelberg 2009 MR Angiography.MR Phys

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,T2 Relaxation (Transverse or Spin–Spin Relaxation),ex forces develop between dipoles moving in close proximity of each other, altering the local magnetic profiles. Thus, numerous sites develop slightly positive or negative deviations from the nominal strength of the main field B. Since the Larmor frequency follows the apparent value of B, there is a

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Partial Saturation,ssue is given plenty of time to regain full strength of its longitudinal magnetization (M.). If TR < T1 (short TR), tissue M. stops very short of M., and is forced to a new steady state called partial saturation.

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Free Induction Decay,(see Chap. 5). Since M. rotates in the xy plane, it is an oscillating magnetic field, and as such it induces the flow of electric current in a coil. Thus, through a coil or antenna the MR signal is transformed into an electric signal that describes a sinusoidal time course with rapid damping (Fig. 1

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Inversion Recovery,e and then collect the echo through a 180° pulse. This sequence is called inversion recovery (IR); it simply incorporates an inversion pulse in front of the standard SE sequence. The new variable, called inversion time (TI), is the delay between the inversion and the excitation pulses. Thus, the fam