To present the physical principles of Magnetic Resonance (MR) phenomenon
To establish the differences between spin echo and gradient echo sequences
To recognize the components of image acquisition and the factors that influence it
To highlight the Fourier transform role in Magnetic Resonance imaging
To present the importance of k space in image formation
MR is a physical phenomenon fundamented in the mechanic and quantum properties of the atomic nucleus.
Matter is composed of atoms.
Elements that have atoms with odd number of electrons have a property known as magnetic moment or spin. This means that they have their own magnetic field.Fig. 1
If a tissue sample is exposed to a magnetic field,
its hydrogen atoms align with this external field with the property described as magnetic moment.
Alignment is a dynamic process,
in which there is a precession...
Findings and procedure details
Now that we know the appropriate background of the MRI,
lets play with sequences,
gradients and all the amazing tools that MRI offer to us.
Types of sequences: spin echo (SE) and gradient echo (GE)
If we want to classify sequences,
we do not divide them into «T1» and «T2» sequences,
but rather SE or GE sequences.
Spin echo formation
To facilitate the graphic representation of echo generation,
we present a scheme Fig. 16 of the artificial state of “rest” (created by...
- MR imaging is the product of serial changes in the mechanics and quantum properties of the protons using electromagnetic waves or gradients
- Knowledge of the physical principles guarantees a better understanding of MR studies
- An adequate MR technique requires time and expertise of the medical physicist,
technicians and radiologists in order to obtain the best information in each study
Thomas B,Shroff MM,Haacke EM: Principles,
andapplications of T2*-based MR imaging and its special applications.
RadioGraphics 2009; 29):1433-1449.
Constable RT:MR Physics of body imaging.
Radiol Clin North Am 2003; 41(1): 1-15.
Ekstrand KE: The Physics or proton NMR.
Med Phys 1982; 9: 807-818.-Duerk JL: Principles of image formation and reconstruction.
MRI Clin North Am 1999; 7(4):629- 659.
Hesselink JR (eds): Clinical Magnetic Resonance Imaging.
WB Saunders Co.Harcourt Brace Jovanovich Inc.
Elster AD: Questions and Answers...