MR physics, MR, Imaging sequences, Tissue characterisation
D. Cicolari1, D. Lizio2, P. Pedrotti2, R. Sironi2, M. T. Moioli2, A. Lascialfari2, M. Mariani1, A. Torresin2; 1Pavia/IT, 2Milan/IT
A good agreement was observed between IR values,
obtained with the three different scanners (NMR spectrometer at Pavia University,
Siemens Aera and General Electric Signa MRI scanners in our Hospital),
and between CPMG and SE values,
obtained respectively with the NMR spectrometer and with the MRI scanners: the expected linear dependence of relaxation times with temperature is observed considering the experimental errors (± 3% for T1 and ± 10% for T2,
limits of agreement,
The correspondence between CPMG (NMR spectrometer) and SE (MRI scanners) values suggests that MRI scanners use a sequence similar to the CPMG one.
Agreement is not found if system response curves are not sampled properly,
especially for T1 estimation methods.
Estimation methods are MRI diagnostic scanner-independent,
but not sequence-independent: as can be seen in NMR spectrometer results,
IR underestimated (15%) values determined with SR.
Gnuplot analysis helped in highlighting estimated relaxation times errors,
of which all information are lost in mapping procedure: analysis methods as those proposed by Kellman et al.
in 2013 ,
the creation and measurements of standard deviation maps associated to parametric maps,
should be considered.