J. Depoorter, NONINVASIVE MRI THERMOMETRY WITH THE PROTON-RESONANCE FREQUENCY METHOD - STUDY OF SUSCEPTIBILITY EFFECTS, Magnetic resonance in medicine, 34(3), 1995, pp. 359-367
The temperature dependence of proton resonance frequency (PRF) is rela
ted to the temperature dependence of the screening constant and of the
volume susceptibility constant, To evaluate the relative importance,
an experimental setup was designed allowing quantification of both eff
ects in different tissues, notably pure water in a gel structure, and
porcine muscle and fat tissue, The temperature varied from 28 to 44 de
grees C, a range significant for hyperthermia applications, Good agree
ment with results from the literature was obtained for water. Porcine
muscle tissue behaves like water, Its screening constant varies linear
ly at a rate of 0.97 10(-8) (degrees C)(-1) and the effects of tempera
ture-induced changes of the susceptibility constant are negligible for
muscle thermometry applications, The PRF-temperature relation in fat
tissue, however, is almost completely determined by susceptibility eff
ects.