title: Precise segmentation of 3-D magnetic resonance angiography.
abstract: Accurate automatic extraction of a 3-D cerebrovascular system from images obtained by time-of-flight (TOF) or phase contrast (PC) magnetic resonance angiography (MRA) is a challenging segmentation problem due to the small size objects of interest (blood vessels) in each 2-D MRA slice and complex surrounding anatomical structures (e.g., fat, bones, or gray and white brain matter). We show that due to the multimodal nature of MRA data, blood vessels can be accurately separated from the background in each slice using a voxel-wise classification based on precisely identified probability models of voxel intensities. To identify the models, an empirical marginal probability distribution of intensities is closely approximated with a linear combination of discrete Gaussians (LCDG) with alternate signs, using our previous EM-based techniques for precise linear combination of Gaussian-approximation adapted to deal with the LCDGs. The high accuracy of the proposed approach is experimentally validated on 85 real MRA datasets (50 TOF and 35 PC) as well as on synthetic MRA data for special 3-D geometrical phantoms of known shapes.
authors.affiliation: Bioengineering Department, University of Louisville, Louisville, KY 40292, USA. aselba01@louisville.edu
authors.forename: Ayman
authors.initials: A
authors.lastname: El-Baz
authors.forename: Ahmed
authors.initials: A
authors.lastname: Elnakib
authors.forename: Fahmi
authors.initials: F
authors.lastname: Khalifa
authors.forename: Mohamed Abou
authors.initials: MA
authors.lastname: El-Ghar
authors.forename: Patrick
authors.initials: P
authors.lastname: McClure
authors.forename: Ahmed
authors.initials: A
authors.lastname: Soliman
authors.forename: Georgy
authors.initials: G
authors.lastname: Gimel'farb
mesh_terms: D000465:Algorithms; D001921:Brain / Q000033:anatomy & histology / Q000098:blood supply; D002560:Cerebrovascular Circulation; D016208:Databases, Factual; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D016011:Normal Distribution; D019047:Phantoms, Imaging; D015203:Reproducibility of Results