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Evaluation of a motion‐robust 2D chemical shift‐encoded technique for R2* and field map quantification in ferumoxytol‐enhanced MRI of the placenta in pregnant rhesus macaques
Author(s) -
Zhu Ante,
Reeder Scott B.,
Johnson Kevin M.,
Nguyen Sydney M.,
Golos Thaddeus G.,
Shimakawa Ann,
Muehler Matthias R.,
Francois Christopher J.,
Bird Ian M.,
Fain Sean B.,
Shah Dinesh M.,
Wieben Oliver,
Hernando Diego
Publication year - 2020
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.26849
Subject(s) - ferumoxytol , medicine , nuclear medicine , magnetic resonance imaging , repeatability , concordance , placenta , radiology , pregnancy , fetus , chemistry , biology , genetics , chromatography
Background 3D chemical shift‐encoded (CSE)‐MRI techniques enable assessment of ferumoxytol concentration but are unreliable in the presence of motion. Purpose To evaluate a motion‐robust 2D‐sequential CSE‐MRI for R2* and B0 mapping in ferumoxytol‐enhanced MRI of the placenta. Study Type Prospective. Animal Model Pregnant rhesus macaques. Field Strength/Sequence 3.0T/CSE‐MRI. Assessment 2D‐sequential CSE‐MRI was compared with 3D respiratory‐gated CSE‐MRI in placental imaging of 11 anesthetized animals at multiple timepoints before and after ferumoxytol administration, and in ferumoxytol phantoms (0 μg/mL–440 μg/mL). Motion artifacts of CSE‐MRI in 10 pregnant women without ferumoxytol administration were assessed retrospectively by three blinded readers (4‐point Likert scale). The repeatability of CSE‐MRI in seven pregnant women was also prospectively studied. Statistical Tests Placental R2* and boundary B0 field measurements (ΔB0) were compared between 2D‐sequential and 3D respiratory‐gated CSE‐MRI using linear regression and Bland–Altman analysis. Results In phantoms, a slope of 0.94 (r 2 = 0.99, concordance correlation coefficient ρ = 0.99), and bias of –4.8 s ‐1 (limit of agreement [LOA], –41.4 s ‐1 , +31.8 s ‐1 ) in R2*, and a slope of 1.07 (r 2 = 1.00, ρ = 0.99) and bias of 11.4 Hz (LOA –12.0 Hz, +34.8 Hz) in ΔB0 were obtained in 2D CSE‐MRI compared with 3D CSE‐MRI for reference R2* ≤390 s ‐1 . In animals, a slope of 0.92 (r 2 = 0.97, ρ = 0.98) and bias of –2.2 s ‐1 (LOA –55.6 s ‐1 , +51.3 s ‐1 ) in R2*, and a slope of 1.05 (r 2 = 0.95, ρ = 0.97) and bias of 0.4 Hz (LOA –9.0 Hz, +9.7 Hz) in ΔB0 were obtained. In humans, motion‐impaired R2* maps in 3D CSE‐MRI (Reader 1: 1.8 ± 0.6, Reader 2: 1.3 ± 0.7, Reader 3: 1.9 ± 0.6), while 2D CSE‐MRI was motion‐free (Reader 1: 2.9 ± 0.3, Reader 2: 3.0 ± 0, Reader 3: 3.0 ± 0). A mean difference of 0.66 s ‐1 and coefficient of repeatability of 9.48 s ‐1 for placental R2* were observed in the repeated 2D CSE‐MRI. Data Conclusion 2D‐sequential CSE‐MRI provides accurate R2* and B0 measurements in ferumoxytol‐enhanced placental MRI of animals in the presence of respiratory motion, and motion‐robustness in human placental imaging. Level of Evidence: 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:580–592.