Comparison of Single Breathold MDixon-Quant and Multi-Echo GRE Methods to Spin Echo Method for Estimating Liver Iron Concentration
J Zhang1*, D Akselrod1, J Gonyea2, S Hipko1,2, J Tam1, M Bazylewicz1, (1) University of Vermont Medical Center, Burlington, VT, (2) University Of Vermont, Burlington, VT
Presentations
TH-IePD-TRACK 2-1 (Thursday, 7/29/2021) 12:30 PM - 1:00 PM [Eastern Time (GMT-4)]
Purpose: Ferriscan is FDA approved to determine liver iron concentration (LIC). It is a spin echo (SE) free breathing technique which is time consuming and motion degraded. We evaluated two single breath-hold
methods: 3D mDixon-quant (mDixon) and multi-echo gradient echo (GRE). LIC from these breath-hold techniques were compared to LIC from Ferriscan.
Methods: Patient population: 12 subjects (age 8-80 years; 8 males), referred to MRI to estimate LIC, were scanned on a 1.5T magnet. The data was retrospectively analyzed. Institutional review board approved waiver of individual consent. MRI parameters:GRE: 16 echoes were acquired at TE1/ΔTE 1.08ms/0.8ms, TR/14ms, Flip angle(FA)/20°, time of acquisition (TA) per breath-hold: 10.7sec. mDixon: 6 echoes were acquired at TE1/ΔTE 0.92ms/0.7ms, TR/5.3ms, FA/5°. TA per breath-hold: 11.6sec. Ferriscan: multi-acquisition to acquire 5 echoes (6ms, 9ms, 12ms, 15ms, and 18ms) for R₂ calculation, TR/1000ms, FA/90°. Each TA: 117sec. Data analysis: The GRE data was fitted to an exponential decay to yield T2* maps. mDixon T₂* maps were derived from a six-point method. LIC(GRE) and LIC(mDixon) were calculated using the equation: LIC[mg/g dry]=0.0254x(1000/T2*[ms])+0.202. Resonance Health calculated the Ferriscan LIC(SE). The agreement between LIC(SE) vs LIC(mDixon) and LIC(GRE) was determined using Bland-Altman analysis.
Results: Ferriscan images from all subjects had significant motion, limiting the area of liver available for LIC evaluaton. mDixon and GRE images had little motion. There was strong agreement (bias ± 2SD): 0.50 ± 1.04 mg/g dry, 0.79 ± 1.06 mg/g dry and 0.29 ± 0.48 mg/g when comparing LIC(GRE) vs LIC(SE), LIC(mDixon) vs LIC(SE), and LIC(mDxion) vs LIC(GRE) respectively.
Conclusion: LIC values from the mDixon and GRE techniques are consistent with the Ferriscan LIC. These results require validation in a larger cohort of patients. An advantage of mDixon, the entire liver is imaged, is the ability to provide both LIC and fat fraction.
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