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Quantitative Magnetic Resonance Fingerprinting (MRF) Has Lower Intra-/Inter-Scanner Variability and Higher Contrast-To-Noise-Ratio Vs. Conventional Contrast-Weighted MRI: Implications for Radiomics and Machine-Learning Applications

L Lu1*, Y Chen2 , J Lian1 , D Fried1 , S Das1 , L Marks1 , W Lin2 , T Zhu1 , (1) Dept. Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA (2) Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA

Presentations

(Tuesday, 7/16/2019) 7:30 AM - 9:30 AM

Room: 225BCD

Purpose: Intra- and inter-scanner variations associated with MRI for radiomics and machine-learning can significantly affect robustness of study results. Using phantom measurements, this study quantitatively assessed intra-/inter-scanner variability and contrast-to-noise-ratio (CNR) of the magnetic resonance fingerprinting (MRF) technique, compared to those with conventional contrast-weighted MRI.

Methods: An MRI phantom with four different concentrations (25%/35%/40%/50%) of polyvinylpyrrolidone (PVP) solution (that has T1 characteristics similar to brain) was scanned using both conventional MPRAGE T1-weighted and an optimized 3D-MRF sequence. For both sequences, the PVP phantom (at all four PVP concentrations) was scanned five times on each of two 3T scanners to assess for both intra- and inter-scanner variability. For each PVP concentration, the magnitude of the intra- and inter-scanner variability was compared for the original MPRAGE T1-weighted and MRF-T1 MRIs, and between their intensity-normalized counterparts (image intensity was normalized by the mean intensity of the PVP sample of 50% concentration to simulate one of the most commonly used normalization approaches in radiomics/machine-learning). CNRs between different PVP concentrations were also calculated for normalized images.

Results: The intra- and inter-scanner variability of the MRF-T1 map was 2.2%±0.8% and 2.5%±0.5%, respectively; vs. 14%±5.0% and 41%±2.2% for the MPRAGE T1-weighted MRI. Although intensity-normalization did improve MPRAGE T1-weighted MRI intra- (5.3%±3.8%) and inter-scanner variability (3.2%±1.6%), both variability levels were significantly higher (p=0.029), up to 5-fold, compared to the normalized MRF-T1. CNR values of normalized MRF-T1 were, on average, 2~3 times higher than with the normalized T1-weighted MRI. The results were similar at all PVP concentrations.

Conclusion: Compared to conventional contrast-weighted MRI, 3D-MRF demonstrates significantly lower intra-/inter-scanner variability and better CNR. Thus, imaging data from the 3D-MRF technique should be more quantitatively consistent across time/scanners and should facilitate more robust multi-center radiomics and model-based machine-learning.

Keywords

MRI, Quantitative Imaging, Quality Control

Taxonomy

IM/TH- MRI in Radiation Therapy: Development (new technology and techniques)

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