title: Effect of hepatocyte-specific gadolinium-based contrast agents on hepatic fat-fraction and R2(⁎).
abstract: The purpose of this work was to investigate the effect of a hepatocyte-specific gadolinium based contrast agent (GBCA) on quantitative hepatic fat-fraction (FF) and R2* measurements. Fifty patients were imaged at 1.5T, using chemical-shift encoded water-fat MRI with low (5°) and high (15°) flip angles (FA), both before and after administration of a hepatocyte-specific GBCA (gadoxetic acid). Low and high FA, pre- and post-contrast FF and R2* values were measured for each subject. Available serum laboratory studies related to liver disease were also recorded. Linear regression and Bland-Altman analysis were performed to compare measurements. Hepatic FF was unaffected by GBCA at low FA (slope=1.02±0.02, p=0.32). FF was overestimated at high FA pre-contrast (slope=1.33±0.03, p<10(-10)), but underestimated post-contrast (slope=0.81±0.02, p<10(-10)). Hepatic R2* was unaffected by FA (mean difference±95% CI pre-contrast:2.2±4.9s(-1), post-contrast:2.8±3.6s(-1)), but increased post-contrast in patients with total bilirubin <2.5mg/dL (ΔR2*=13.4±12.7s(-1)). Regression analysis of serum values demonstrated a correlation of post-contrast change in R2* with total bilirubin (p<0.01) and model for end-stage liver disease (MELD) score (p≈0.01). In conclusion, GBCA has no effect on hepatic FF at low FA due to a lack of T1-weighting, potentially allowing flexibility for FF imaging with hepatobiliary imaging protocols. Hepatic R2* increased significantly after GBCA administration, particularly in the biliary tree. Therefore, R2* maps should be obtained prior to contrast administration.
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States. Electronic address: dhernando@wisc.edu.
authors.forename: Diego
authors.initials: D
authors.lastname: Hernando
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States; Department of Radiology, University of Virginia, Charlottesville, VA.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Wells
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States.
authors.forename: Karl K
authors.initials: KK
authors.lastname: Vigen
authors.affiliation: Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States; Department of Medical Physics, University of Wisconsin - Madison, Madison, WI, United States; Department of Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States; Department of Medicine, University of Wisconsin - Madison, Madison, WI, United States.
authors.forename: Scott B
authors.initials: SB
authors.lastname: Reeder
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001663:Bilirubin / Q000097:blood; D003287:Contrast Media / Q000737:chemistry; D058625:End Stage Liver Disease / Q000097:blood; D005260:Female; D005682:Gadolinium / Q000737:chemistry*; D019786:Gadolinium DTPA / Q000737:chemistry; D022781:Hepatocytes / Q000166:cytology / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016014:Linear Models; D008099:Liver / Q000378:metabolism / Q000503:physiopathology*; D008107:Liver Diseases / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D014867:Water / Q000737:chemistry; D055815:Young Adult
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D014867:Water; D005682:Gadolinium; D019786:Gadolinium DTPA; D001663:Bilirubin
keywords: Fat quantification; Fat-fraction; Fat–Water imaging; Gadoxetic acid; Iron quantification; R2*