Interexamination repeatability and spatial heterogeneity of liver iron and fat quantification using MRI-based multistep adaptive fitting algorithm

• Published in: Journal of magnetic resonance imaging Vol. 42; no. 5; pp. 1281 - 1290
• Main Authors: Sofue, Keitaro, Mileto, Achille, Dale, Brian M., Zhong, Xiaodong, Bashir, Mustafa R.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.11.2015; Wiley Subscription Services, Inc
• Subjects: Adiposity; Adolescent; Adult; Aged; Aged, 80 and over; Algorithms; Fats - metabolism; Female; heterogeneity; Humans; Image Interpretation, Computer-Assisted - methods; Iron - metabolism; Liver - metabolism; liver fat; liver iron; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Middle Aged; Prospective Studies; repeatability; Reproducibility of Results; Young Adult; repeatability; liver iron; magnetic resonance imaging; liver fat; heterogeneity
• ISSN: 1053-1807; 1522-2586; 1522-2586
• DOI: 10.1002/jmri.24922

Purpose To assess the interexamination repeatability and spatial heterogeneity of liver iron and fat measurements using a magnetic resonance imaging (MRI)‐based multistep adaptive fitting algorithm. Materials and Methods This prospective observational study was Institutional Review Board‐approved and Health Insurance Portability and Accountability Act‐compliant. Written informed consent was waived. In all, 150 subjects were imaged on 3T MRI systems. A whole‐liver volume acquisition was performed twice using a six‐echo 3D spoiled gradient echo sequence during two immediately adjacent examinations. Colocalized regions of interest (ROIs) in three different hepatic segments were placed for R2* and proton density fat fraction (PDFF) measurements by two readers independently. Mean R2* and PDFF values between readers and acquisitions were compared using the Wilcoxon signed‐rank test, intraclass correlation coefficients (ICCs), linear regression, Bland–Altman analysis, and analysis of variance (ANOVA). Results The mean R2* and PDFF values across all ROIs and measurements were 51.2 ± 25.2 s−1 and 6.9 ± 6.4%, respectively. Mean R2* and PDFF values showed no significant differences between the two acquisitions (P = 0.05–0.87). Between the two acquisitions, R2* and PDFF values demonstrated almost perfect agreement (ICCs = 0.979–0.994) and excellent correlation (R2 = 0.958–0.989). Bland–Altman analysis also demonstrated excellent agreement. In the ANOVA, the individual patient and ROI location were significant effects for both R2* and PDFF values (P < 0.05). Conclusion MRI‐based R2* and PDFF measurements are repeatable between examinations. Between‐measurement changes in R2* of more than 10.1 s−1 and in PDFF of more than 1.7% are likely due to actual tissue changes. Liver iron and fat content are variable between hepatic segments. J. Magn. Reson. Imaging 2015;42:1281–1290.