title: T1 Mapping by CMR Imaging: From Histological Validation to Clinical Implication.
abstract: OBJECTIVE
  The purpose of this study was to prospectively investigate the diagnostic and prognostic impact of cardiac magnetic resonance (CMR) T1 mapping and validate it against left ventricular biopsies.
  
  
  BACKGROUND
  Extracellular volume (ECV) expansion is a key feature of heart failure. CMR T1 mapping has been developed as a noninvasive technique to estimate ECV; however, the diagnostic and prognostic impacts of this technique have not been well established.
  
  
  METHODS
  A total of 473 consecutive patients referred for CMR (49.5% female, age 57.8 ± 17.1 years) without hypertrophic cardiomyopathy, cardiac amyloidosis, or Anderson-Fabry disease were studied. T1 mapping with the modified Look-Locker inversion recovery (MOLLI) sequence was used for ECV calculation (CMR-ECV). For methodological validation, 36 patients also underwent left ventricular biopsy, and ECV was quantified by TissueFAXS analysis (TissueFAXS-ECV). To assess the prognostic value of CMR-ECV, its association with hospitalization for cardiovascular reasons or cardiac death was tested in a multivariable Cox regression model.
  
  
  RESULTS
  TissueFAXS-ECV was 26.3 ± 7.2% and was significantly correlated with CMR-ECV (r = 0.493, p = 0.002). Patients were followed up for 13.3 ± 9.0 months and divided into CMR-ECV tertiles for Kaplan-Meier analysis (tertiles were ≤ 25.7%, 25.8% to 28.5%, and ≥ 28.6%). Significantly higher event rates were observed in patients with higher CMR-ECV (log-rank p = 0.013). By multivariable Cox regression analysis, CMR-ECV was independently associated with outcome among imaging variables (p = 0.004) but not after adjustment for clinical parameters.
  
  
  CONCLUSIONS
  CMR T1 mapping allows accurate noninvasive quantification of ECV and is independently associated with event-free survival among imaging parameters. Its prognostic value on top of established clinical risk factors warrants further investigation in long-term studies.
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Andreas A
authors.initials: AA
authors.lastname: Kammerlander
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Beatrice A
authors.initials: BA
authors.lastname: Marzluf
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Caroline
authors.initials: C
authors.lastname: Zotter-Tufaro
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Aschauer
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Duca
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Alina
authors.initials: A
authors.lastname: Bachmann
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Knechtelsdorfer
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Wiesinger
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pfaffenberger
authors.affiliation: Siemens Healthcare GmbH, Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Greiser
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Irene M
authors.initials: IM
authors.lastname: Lang
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria.
authors.forename: Diana
authors.initials: D
authors.lastname: Bonderman
authors.affiliation: Division of Cardiology, Medical University of Vienna, Vienna, Austria. Electronic address: julia.mascherbauer@meduniwien.ac.at.
authors.forename: Julia
authors.initials: J
authors.lastname: Mascherbauer
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D016009:Chi-Square Distribution; D003287:Contrast Media; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D006333:Heart Failure / Q000401:mortality / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy; D006352:Heart Ventricles / Q000473:pathology* / Q000503:physiopathology; D006760:Hospitalization; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009206:Myocardium / Q000473:pathology*; D009942:Organometallic Compounds; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D015203:Reproducibility of Results; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol
keywords: T1 mapping; cardiac magnetic resonance imaging; extracellular matrix; outcome