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Design and evaluation of quantitative MRI phantoms to mimic the simultaneous presence of fat, iron, and fibrosis in the liver
Author(s) -
Zhao Ruiyang,
Hamilton Gavin,
Brittain Jean H.,
Reeder Scott B.,
Hernando Diego
Publication year - 2021
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.28452
Subject(s) - chemistry , steatosis , nuclear medicine , homogeneous , magnetic resonance imaging , nuclear magnetic resonance , biomedical engineering , medicine , radiology , mathematics , physics , combinatorics
Purpose To design, construct, and evaluate quantitative MR phantoms that mimic MRI signals from the liver with simultaneous control of three parameters: proton‐density fat fraction (PDFF), R 2 ∗ , and T 1 . These parameters are established biomarkers of hepatic steatosis, iron overload, and fibrosis/inflammation, respectively, which can occur simultaneously in the liver. Methods Phantoms including multiple vials were constructed. Peanut oil was used to modulate PDFF, MnCl 2 and iron microspheres were used to modulate R 2 ∗ , and NiCl 2 was used to modulate the T 1 of water (T 1,water ). Phantoms were evaluated at both 1.5 T and 3 T using stimulated‐echo acquisition‐mode MRS and chemical shift–encoded MRI. Stimulated‐echo acquisition‐mode MRS data were processed to estimate T 1,water , T 1,fat , R 2 , water ∗ , and R 2 , fat ∗ for each vial. Chemical shift–encoded MRI data were processed to generate PDFF and R 2 ∗ maps, and measurements were obtained in each vial. Measurements were evaluated using linear regression and Bland‐Altman analysis. Results High‐quality PDFF and R 2 ∗ maps were obtained with homogeneous values throughout each vial. High correlation was observed between imaging PDFF with target PDFF (slope = 0.94‐0.97, R 2 = 0.994‐0.997) and imaging R 2 ∗ with target R 2 ∗ (slope = 0.84‐0.88, R 2 = 0.935‐0.943) at both 1.5 T and 3 T. The values of R 2 , fat ∗ and R 2 , water ∗ were highly correlated with slope close to 1.0 at both 1.5 T (slope = 0.90, R 2 = 0.988) and 3 T (slope = 0.99, R 2 = 0.959), similar to the behavior observed in vivo. The value of T 1,water (500‐1200 ms) was controlled with varying NiCl 2 concentration, while T 1,fat (300 ms) was independent of NiCl 2 concentration. Conclusion Novel quantitative MRI phantoms that mimic the simultaneous presence of fat, iron, and fibrosis in the liver were successfully developed and validated.