title: Automatic extraction of three-dimensional thoracic aorta geometric model from phase contrast MRI for morphometric and hemodynamic characterization.
abstract: OBJECTIVE
  To propose and assess a new method that automatically extracts a three-dimensional (3D) geometric model of the thoracic aorta (TA) from 3D cine phase contrast MRI (PCMRI) acquisitions.
  
  
  METHODS
  The proposed method is composed of two steps: segmentation of the TA and creation of the 3D geometric model. The segmentation algorithm, based on Level Set, was set and applied to healthy subjects acquired in three different modalities (with and without SENSE reduction factors). Accuracy was evaluated using standard quality indices. The 3D model is characterized by the vessel surface mesh and its centerline; the comparison of models obtained from the three different datasets was also carried out in terms of radius of curvature (RC) and average tortuosity (AT).
  
  
  RESULTS
  In all datasets, the segmentation quality indices confirmed very good agreement between manual and automatic contours (average symmetric distance < 1.44 mm, DICE Similarity Coefficient > 0.88). The 3D models extracted from the three datasets were found to be comparable, with differences of less than 10% for RC and 11% for AT.
  
  
  CONCLUSIONS
  Our method was found effective on PCMRI data to provide a 3D geometric model of the TA, to support morphometric and hemodynamic characterization of the aorta.
authors.affiliation: Institute of Molecular Bioimaging and Physiology, CNR, Segrate (MI), Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Volonghi
authors.affiliation: Institute of Molecular Bioimaging and Physiology, CNR, Segrate (MI), Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Tresoldi
authors.affiliation: Philips Healthcare, Monza, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Cadioli
authors.affiliation: Institute of Molecular Bioimaging and Physiology, CNR, Segrate (MI), Italy.
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Usuelli
authors.affiliation: CINECA, Segrate (MI), Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Ponzini
authors.affiliation: Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.
authors.forename: Umberto
authors.initials: U
authors.lastname: Morbiducci
authors.affiliation: Department of Radiology, Scientific Institute H.S. Raffaele, Milan, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Esposito
authors.affiliation: Institute of Molecular Bioimaging and Physiology, CNR, Segrate (MI), Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Rizzo
mesh_terms: D000328:Adult; D000465:Algorithms; D001013:Aorta, Thoracic / Q000033:anatomy & histology*; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*
keywords: 3D geometric model; level set segmentation; phase contrast MRI; thoracic aorta