title: Three-dimensional histology: tools and application to quantitative assessment of cell-type distribution in rabbit heart.
abstract: OBJECTIVE
  Cardiac histo-anatomical organization is a major determinant of function. Changes in tissue structure are a relevant factor in normal and disease development, and form targets of therapeutic interventions. The purpose of this study was to test tools aimed to allow quantitative assessment of cell-type distribution from large histology and magnetic resonance imaging- (MRI) based datasets.
  
  
  RESULTS
  Rabbit heart fixation during cardioplegic arrest and MRI were followed by serial sectioning of the whole heart and light-microscopic imaging of trichrome-stained tissue. Segmentation techniques developed specifically for this project were applied to segment myocardial tissue in the MRI and histology datasets. In addition, histology slices were segmented into myocytes, connective tissue, and undefined. A bounding surface, containing the whole heart, was established for both MRI and histology. Volumes contained in the bounding surface (called 'anatomical volume'), as well as that identified as containing any of the above tissue categories (called 'morphological volume'), were calculated. The anatomical volume was 7.8 cm(3) in MRI, and this reduced to 4.9 cm(3) after histological processing, representing an 'anatomical' shrinkage by 37.2%. The morphological volume decreased by 48% between MRI and histology, highlighting the presence of additional tissue-level shrinkage (e.g. an increase in interstitial cleft space). The ratio of pixels classified as containing myocytes to pixels identified as non-myocytes was roughly 6:1 (61.6 vs. 9.8%; the remaining fraction of 28.6% was 'undefined').
  
  
  CONCLUSIONS
  Qualitative and quantitative differentiation between myocytes and connective tissue, using state-of-the-art high-resolution serial histology techniques, allows identification of cell-type distribution in whole-heart datasets. Comparison with MRI illustrates a pronounced reduction in anatomical and morphological volumes during histology processing.
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
authors.forename: Rebecca A B
authors.initials: RA
authors.lastname: Burton
authors.affiliation: Department of Physics, University of Oxford, Oxford OX1 3RH, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Lee
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Ramón
authors.initials: R
authors.lastname: Casero
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Garny
authors.affiliation: The Heart Science Centre, National Heart and Lung Institute, Imperial College London, Harefield UB9 6JH, UK.
authors.forename: Urszula
authors.initials: U
authors.lastname: Siedlecka
authors.affiliation: British Heart Foundation Experimental MR Unit, Radcliffe Department of Medicine, Division of Cardiovascular Medicine, University of Oxford, Oxford OX3 7BN, UK.
authors.forename: Jürgen E
authors.initials: JE
authors.lastname: Schneider
authors.affiliation: The Heart Science Centre, National Heart and Lung Institute, Imperial College London, Harefield UB9 6JH, UK p.kohl@imperial.ac.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Kohl
authors.affiliation: Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Vicente
authors.initials: V
authors.lastname: Grau
mesh_terms: D000818:Animals; D003196:Computer Graphics; D003198:Computer Simulation; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006324:Heart Arrest, Induced; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D023421:Models, Animal; D008955:Models, Cardiovascular; D009206:Myocardium / Q000473:pathology*; D032383:Myocytes, Cardiac / Q000473:pathology; D011817:Rabbits
keywords: Cardiac MRI; Computational models; Connective tissue; Myocytes; Serial histology