Type:
Educational Exhibit
Keywords:
Radiographers, MR physics, MR, Education, Physics, Technical aspects, Education and training, Artifacts
Authors:
V. G. Syrgiamiotis1, V. Maliakas2, T. Thomas1, L. G. Astrakas2, M. Argyropoulou2, A. Ploussi1; 1Athens /GR, 2Ioannina/GR
DOI:
10.1594/ecr2018/C-0027
Background
Magnetic and Electrical Fields in MRI
In the MRI,
together with the B1 of the RF coexists an electric field (E1).
As described by the Maxwell equations,
the fields B1 and E1 oscillate vertically with each other in the direction of wave propagation.
When electromagnetic waves meet the human body,
various phenomena occur
The main ones are the following:
(i) wavelength reduction
(ii) electrical current generation and
(iii) somewhat reflection / refraction of wave during the transition between different tissues.
In all of the images a central area of reduced intensity ("dark area") is observed due to the dielectric phenomenon,
which develops strongly due to the strong magnetic field (3T) and the presence of the cystic large structure,
which is a tissue with high conductivity,
the creation of stagnant waves and the intense appearance of the phenomenon.
vii,
viii and ix: T2 images TSE sequences at transverse,
sagittal and frontal plane.
(MT 1.5 Tesla University hospital of Ioannina)