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Single spin‐echo proton transverse relaxometry of iron‐loaded liver
Author(s) -
St Pierre Timothy G.,
Clark Paul R.,
Chuaanusorn Wanida
Publication year - 2004
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.905
Subject(s) - relaxometry , nuclear magnetic resonance , spin echo , proton , transverse plane , spin (aerodynamics) , materials science , physics , chemistry , condensed matter physics , magnetic resonance imaging , nuclear physics , medicine , radiology , thermodynamics
A single‐spin‐echo methodology is described for the measurement and imaging of proton transverse relaxation rates (R 2 ) in iron‐loaded and normal human liver tissue in vivo . The methodology brings together previously reported techniques dealing with (i) the changes in gain between each spin‐echo acquisition, (ii) signal level offset due to background noise, (iii) estimation of signal intensities in decay curves at time zero to enable reliable extraction of relaxation times from tissues with very short T 2 values, (iv) bi‐exponential modelling of decay curves with a small number of data points, and (v) reduction of respiratory motion artefacts. The accuracy of the technique is tested on aqueous manganese chloride solutions yielding a relaxivity of 74.1 ± 0.3 s −1 (m M ) −1 , consistent with previous reports. The precision of the in vivo measurement of mean liver R 2 values is tested through duplicate measurements on 10 human subjects with mean liver R 2 values ranging from 26 to 220 s −1 . The random uncertainty on the measurement of mean liver R 2 was found to be 7.7%. Copyright © 2004 John Wiley & Sons, Ltd.