MEDRADSC 3DE3 Lecture Notes - Lecture 5: Physics Of Magnetic Resonance Imaging, Intrinsic Factor, Larmor Precession

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 3DE3
• Professor: Alana Trainor

Document Summary

Now that the extra energy is no longer there, nmv returns to bo, recovery of magnetization in longitudinal plane. Independently, but at the same time, h dephase, lose coherence, deacy of magnetization in transverse plane. Remember: t1 & t2 decay at 2 different rates - decay occurs 5-10x faster than t1 recovery. Fat recovers to longitudinal very quick, water decays very slow. If there is no contrast, it is impossible to tell the difference between normal tissue/anatomy & abnormal anatomy/pathology. X-ray example: density of the tissue were imaging. Proton density: extrinsic contrast parameters - can be changed. H nuclei give up their extra energy to the surrounding environment/structure (aka surrounding lattice) When they have excess energy from first excitation or subsequent rf pulses, we flip into transverse plane. When process carries on & relaxation occurs, h nuclei give up excess energy to surrounding environment (spin-lattice or recovery)