Mechanisms of tissue-iron relaxivity: Nuclear magnetic resonance studies of human liver biopsy specimens
Mechanisms of tissue-iron relaxivity: Nuclear magnetic resonance studies of human liver biopsy specimens
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DOI：
10.1002/mrm.20697
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发表时间：
2005-11-01
影响因子：
3.3
通讯作者：
Wood, JC
中科院分区：
文献类型：
--
作者：
Ghugre, NR;Coates, TD;Wood, JC
MRI is becoming an increasingly important tool to assess iron overload disorders, but the complex nature of proton-iron interactions has troubled noninvasive iron quantification. Intersite and intersequence variability as well as methodological inaccuracies have been limiting factors to its widespread clinical use. It is important to understand the underlying proton relaxation mechanisms within the (human) tissue environment to address these differences. In this respect, NMR relaxometry was performed on 10 fresh human liver biopsy specimens taken from patients with transfusion-dependent anemia. T-1 (1/R-1) inversion recovery, T-2 (1/R-2) single echo, and multiecho T-2 CPMG measurements were performed on a 60-MHz Bruker Minispectrometer. NMR parameters were compared to quantitative iron levels and tissue histology. Relaxivities R-1 and R-2 both increased linearly with hepatic iron content, with R2 being more sensitive to iron. CPMG data were well described by a chemical -exchange model and predicted effective iron center dimensions consistent with hemosiderin-filled lysosomes. Nonexponential relaxation was evident at short refocusing intervals with R-2 and amplitude behavior suggestive of magnetic susceptibility-based compartmentalization rather than anatomic subdivisions. NMR relaxometry of human liver biopsy specimens yields unique insights into the mechanisms of tissue-iron relaxivity. Magn Reson Med 54:1185-1193, 2005. (c) 2005 Wiley-Liss, Inc.
