title: Gadofosveset-based biomarker of tissue albumin concentration: Technical validation in vitro and feasibility in vivo.
abstract: OBJECTIVE
  There is currently no adequate method of mapping physiologic and pathophysiologic tissue albumin concentrations in human subjects. The objective of this study was to devise and evaluate a biomarker of regional albumin concentration using gadofosveset-enhanced MRI.
  
  
  METHODS
  A binding and relaxation model was devised and evaluated in vitro in solutions of albumin at 3.0 Tesla (T) and 4.7T. The method was evaluated in the heart in seven volunteers at 3.0T.
  
  
  RESULTS
  MRI-derived estimates of albumin concentration were in good agreement with true values over the range 0.1-1.0 mM (Pearson correlation coefficients of 0.85 and 0.88 for 3.0T and 4.7T, respectively). The mean calculated albumin concentration in the myocardium for the volunteers was 0.02 mM (range, 0.01-0.03 mM).
  
  
  CONCLUSIONS
  Accurate estimates of albumin concentration in vitro suggest this may be a viable noninvasive alternative to existing techniques. In the myocardium the MRI-derived estimates of albumin concentration indicate the practical feasibility of the technique but were below expected values. Gadofosveset-enhanced MR relaxometry has potential in providing biomarkers of regional albumin concentration; further evaluation is required before it can be used reliably in vivo.
authors: Division of Medical Physics, University of Leeds, Leeds, United Kingdom.
authors: Owen C
authors: OC
authors: Richardson
authors: Departments of Biomedical Engineering and Radiology, Northwestern University, Chicago, Illinois, USA.
authors: Octavia
authors: O
authors: Bane
authors: Personalized Healthcare and Biomarkers, AstraZeneca, Macclesfield, Cheshire, United Kingdom.
authors: Marietta L J
authors: ML
authors: Scott
authors: Department of Medical Physics and Engineering, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom.
authors: Steven F
authors: SF
authors: Tanner
authors: Personalized Healthcare and Biomarkers, AstraZeneca, Macclesfield, Cheshire, United Kingdom.
authors: John C
authors: JC
authors: Waterton
authors: Division of Medical Physics, University of Leeds, Leeds, United Kingdom.
authors: Steven P
authors: SP
authors: Sourbron
authors: Departments of Biomedical Engineering and Radiology, Northwestern University, Chicago, Illinois, USA.
authors: Timothy J
authors: TJ
authors: Carroll
authors: Division of Medical Physics, University of Leeds, Leeds, United Kingdom.
authors: David L
authors: DL
authors: Buckley
mesh_terms: D000328:Adult; D000418:Albumins / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D005240:Feasibility Studies; D005260:Female; D005682:Gadolinium / Q000493:pharmacokinetics*; D006321:Heart / Q000033:anatomy & histology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008954:Models, Biological; D057054:Molecular Imaging / Q000379:methods*; D009206:Myocardium / Q000378:metabolism*; D009942:Organometallic Compounds / Q000493:pharmacokinetics*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution
chemical_list: D000418:Albumins; D015415:Biomarkers; D003287:Contrast Media; D009942:Organometallic Compounds; D005682:Gadolinium; C109932:gadofosveset trisodium
keywords: albumin; binding; biomarker; gadofosveset; relaxivity