A hybrid (iron –fat–water) phantom for liver iron overload quantification in the presence of contaminating fat using magnetic resonance imaging

This study proposes a phantom design concomitantly containing various concentrations of iron and fat suitable for devising accurate simultaneousT2* and fat quantification technique.Materials and methodsA 46-vial iron –fat–water phantom with various iron concentrations covering clinically relevantT2* 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.ResultsSize 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\({\text{Fe}} = - 28.02 + \frac{302.84}{{T2^{*} }} - 0.045\,{\text{FF}}\), with R-squared  = 0.89.DiscussionThe proposed phantom design with microsphere iron particles closely simulated the single-T2* ...
Source: Magnetic Resonance Materials in Physics, Biology and Medicine - Category: Materials Science Source Type: research