title: Diffusion Tensor Imaging of Healthy and Infarcted Porcine Hearts: Study on the Impact of Formalin Fixation.
abstract: BACKGROUND
  Due to complexities ofin-vivocardiac diffusion tensor imaging (DTI),ex-vivoformalin-fixed specimens are used to investigate cardiac remodeling in diseases, and reported results have shown conflicting trends. This study investigates the impact of formalin-fixation on diffusion properties and optimizes tracking parameters based on controls to understand remodeling in myocardial-infarction (MI).
  
  
  METHODS
  DTI was performed on 4 healthy (controls) and 4 MI induced formalin-fixed (PoMI)ex-vivoporcine hearts. Controls were scanned pre-fixation (PrCtrl) and re-scanned (PoCtrl) after formalin-fixation. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were estimated in all hearts. Tracking parameters (FA, tract termination angle (TTA), fiber-length) were optimized in controls and then used to investigate structural remodeling in PoMI hearts.
  
  
  RESULTS
  Fixation increased ADC and decreased FA. PoMI showed increased ADC but decreased FA in infarcted zone compared to remote zone. TTA showed sharp increase in slope from 5°-10°, which flattened after 25° in all groups. Mean fiber-length for different tracking length range showed that PoCtrl had shorter fibers compared to PrCtrl. Fibers around infarction were shorter in length and disarrayed compared to PoCtrl group.
  
  
  CONCLUSIONS
  Formalin-fixation affects diffusion properties and hence DTI parametric trends observed in pathology may be influenced by the fixation process which can cause contradictory findings.
authors.affiliation: Department of Electrical and Computer Engineering, 205 Dreese Laboratories, 2015 Neil Avenue, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Ria
authors.initials: R
authors.lastname: Mazumder
authors.affiliation: Department of Radiology, Room 460, 395 W. 12th Avenue, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Seongjin
authors.initials: S
authors.lastname: Choi
authors.affiliation: Department of Electrical and Computer Engineering, 205 Dreese Laboratories, 2015 Neil Avenue, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Clymer
authors.affiliation: Department of Radiology, Room 460, 395 W. 12th Avenue, The Ohio State University, Columbus, Ohio 43210, USA; Department of Internal Medicine-Division of Cardiovascular Medicine, 244 Davis Heart & Lung Research Institute, 473 W. 12th Avenue, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Richard D
authors.initials: RD
authors.lastname: White
authors.affiliation: Department of Radiology, Room 460, 395 W. 12th Avenue, The Ohio State University, Columbus, Ohio 43210, USA; Department of Internal Medicine-Division of Cardiovascular Medicine, 244 Davis Heart & Lung Research Institute, 473 W. 12th Avenue, The Ohio State University, Columbus, Ohio 43210, USA.
authors.forename: Arunark
authors.initials: A
authors.lastname: Kolipaka
keywords: Myocardial infarction (MI); diffusion tensor imaging (DTI); formalin-fixation; remodeling