A Hybrid (Iron–Fat–Water) Phantom for Liver Iron Overload Quantification in the Presence of Contaminating Fat Using Magnetic Resonance Imaging Publisher Pubmed



Mobini N^{1, 2} ; Malekzadeh M^{2, 3} ; Haghighatkhah H⁴ ; Saligheh Rad H^{1, 2}
Source: Magnetic Resonance Materials in Physics# Biology and Medicine Published:2020

Abstract

Objective: Assessment of iron content in the liver is crucial for diagnosis/treatment of iron-overload diseases. Nonetheless, T2*-based methods become challenging when fat and iron are simultaneously present. This study proposes a phantom design concomitantly containing various concentrations of iron and fat suitable for devising accurate simultaneous T2* and fat quantification technique. Materials and methods: A 46-vial iron–fat–water phantom with various iron concentrations covering clinically relevant T2* relaxation time values, from healthy to severely overloaded liver and wide fat percentages ranges from 0 to 100% was prepared. The phantom was constructed using insoluble iron (II, III) oxide powder containing microscale particles. T2*-weighted imaging using multi-gradient-echo (mGRE) sequence, and chemical shift imaging spin-echo (CSI-SE) Magnetic Resonance Spectroscopy (MRS) data were considered for the analysis. T2* relaxation times and fat fractions were extracted from the MR signals to explore the effects of fat and iron overload. Results: Size distribution of iron oxide particles for Magnetite fits with a lognormal function with a mean size of about 1.17 µm. Comparison of FF color maps, estimated from bi- and mono-exponential model indicated that single-T2* fitting model resulted in lower NRMSD. Therefore, T2* values from the mono-exponential signal equation were used and expressed the relationship between relaxation time value across all iron (Fe) and fat concentration as Fe=-28.02+302.84T2∗-0.045FF, with R-squared = 0.89. Discussion: The proposed phantom design with microsphere iron particles closely simulated the single-T2* behavior of fatty iron-overloaded liver in vivo. © 2019, European Society for Magnetic Resonance in Medicine and Biology (ESMRMB).