Novel Sampling Strategy for Improved Reproducibility in Quantitative T1rho Mapping
C Wu1*, Q Peng2, (1) Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA (2) Department of Radiology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA
Presentations
TH-C-TRACK 3-5 (Thursday, 7/29/2021) 1:00 PM - 2:00 PM [Eastern Time (GMT-4)]
Purpose: T1rho (T1ρ) mapping emerges as a promising MRI tool for quantitative evaluation of low-frequency biochemical changes. However, the accuracy and reproducibility of T1ρ quantification can be compromised by B0 and B1 field inhomogeneities. The purpose of this study was to develop a novel sampling strategy of spin-locking time (TSL) for improved reproducibility in quantitative T1ρ mapping.
Methods: Two TSL sampling strategies were compared in simulation and phantom experiments. The first one was the standard sampling strategy where TSLs were sampled in a linearly spaced fashion (TSL-LS). The second one was a novel TSL sampling strategy called precision- and reproducibility-guided TSL sampling (TSL-PRG) where all TSLs, except TSL=0 ms, were sampled near the expected T1ρ value of interest at a constant interval defined by the Mz oscillation frequency. Simulation was repeated 100 times with field offsets of B0 (±600 Hz) an B1 (±50%) in a 50×50 grid where the percentage of T1ρ errors < 5% (T1ρ_Error_5pt) and the coefficients of variation < 5% (T1ρ_CV_5pt) were compared. For phantom experiment, T1ρ standard deviations in the three tubes at 150 Hz B0 off-resonance were compared.
Results: Simulation showed that TSL-PRG had slightly better T1ρ quantification accuracy within the range of B0 and B1 offsets (T1ρ_Error_5pt: 30.4% versus 32.8% for TSL-LS and TSL-PRG, respectively). Moreover, T1ρ variation was substantially reduced for TSL-PRG (T1ρ_CV_5pt: 44.3% versus 67.0% for TSL-LS and TSL-PRG, respectively). In the phantom experiment, standard deviation of T1ρ values at about 150 Hz B0 off-resonance was significantly reduced for TSL-PRG compared to TSL-LS in all three tubes (average of 5.40±0.75 ms versus 8.70±2.25 ms, P<0.001).
Conclusion: This study demonstrated that the proposed TSL-PRG sampling strategy produced more reproducible T1ρ quantification compared to standard linearly spaced TSL sampling (TSL-LS), suggesting the importance of TSL selection in quantitative T1ρ mapping.
Handouts
Keywords
MRI, Quantitative Imaging, Magnetic Fields
Taxonomy
IM- MRI : Quantitative Imaging
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