Preliminary study of distribution and age-related changes of iron-content in the brain using MR quantitative susceptibility mapping / 中华放射学杂志

ABSTRACT

Objective To evaluate the distribution and age-related changes of brain iron content in healthy people using MR quantitative susceptibility mapping (QSM).Methods Sixty three healthy right-handed volunteers underwent the routine MRI and SWI scan to get SWI-unfiltered phase images and magnitude images.QSM were reconstructed from the SWI-unfiltered phase images and magnitude images using SMART software.The regions of interest at the bilateral frontal white matter and nuclei (caudate nuclews,globus pallidus,putamen,substantia nigra,dorsal thalamus,red nucleus and dental nucleus) were drawn manually,and the susceptibility was measured.The linear correlation between the susceptibility and iron concentration cited from Hallgren and Sourander's post-mortem brain study was calculated.Wilcoxon test were applied to calculate the difference between the bilateral frontal white matter and bilateral nuclei.The correlation of age with susceptibility of bilateral frontal white matter and bilateral nuclei were analyzed by Spearman correlation analysis.Results The median susceptibility (extent) of frontal white matter,caudate nucleus,globus pallidus,putamen,dorsal thalamus,substantia nigra,red nucleus and dentate nucleus of 63 healthy people were-12.81 (-31.56,8.72),39.27 (22.35,75.13),93.99 (19.19,158.75),29.16 (4.11,81.53),2.91 (-27.80,27.95),83.14 (38.57,185.79),63.49 (13.83,142.09),63.30 (36.78,128.53) ppb (× 10-9),respectively.There was high consistency with Hallgren and Sourander's study (r=0.91,P＜0.05).The susceptibility of globus pallidus was the highest,followed by substantia nigra.The least susceptibility was seen in the frontal white matter.The susceptibility of right caudate nucleus,substantia nigra,red nucleus and dental nucleus was higher than that of left side (Z value was-3.18,-4.44,-3.70 and-2.64,respectively,P＜0.05).The susceptibility of bilateral globus pallidus of the male was significantly different from that of the female (Z value was-2.27 and-2.42,respectively,P＜0.05).There was positive correlation between age and the susceptibility of bilateral caudate nucleus,putamen,red nucleus and dental nucleus (r value was 0.30 to 0.49,P＜0.05).Conclusions QSM based on the SWI-unfiltered phase and magnitude images can clearly display the cerebral nuclei and evaluate the brain iron content accurately,which is consistent with the histopathological results.Iron content of bilateral caudate nucleus,putamen,red nucleus and dental nucleus increase with aging.