title: Fully automated reconstruction of ungated ghost magnetic resonance angiograms.
abstract: OBJECTIVE
  To completely automate the reconstruction process during noncardiac-gated unenhanced ghost magnetic resonance angiography (MRA).
  
  
  METHODS
  Ungated unenhanced ghost MRA of the calf was performed in 16 volunteers. K-means and fuzzy c-means (FCM) clustering algorithms using prominent image features were applied to automatically create angiograms of the calf in volunteers undergoing ungated ghost MRA. Ghost angiograms reconstructed automatically were compared to those created manually on the basis of diagnostic image quality and apparent arterial-to-background contrast-to-noise ratio (CNR). Images were also ranked by an expert user in their order of preference using an ordinal scale.
  
  
  RESULTS
  Compared with the ghost angiograms created manually, ghost angiograms reconstructed automatically with the use of clustering analysis provided similar arterial-to-background CNR values. No differences in diagnostic quality or preference were identified between images reconstructed manually and automatically.
  
  
  CONCLUSIONS
  We present fully automated image reconstruction algorithms for use with ungated and unenhanced ghost MRA. These automated algorithms, based on the use of k-means or FCM clustering, can be used to eliminate manual postprocessing that is time-consuming and subject to variability.
authors.affiliation: Department of Electrical Engineering and Computer Science, Northwestern University, Evanston, Illinois 60208, USA. s-tsaftaris@northwestern.edu
authors.forename: Sotirios A
authors.initials: SA
authors.lastname: Tsaftaris
authors.forename: Erik
authors.initials: E
authors.lastname: Offerman
authors.forename: Robert R
authors.initials: RR
authors.lastname: Edelman
authors.forename: Ioannis
authors.initials: I
authors.lastname: Koktzoglou
mesh_terms: D000328:Adult; D000465:Algorithms; D055424:Cardiac-Gated Imaging Techniques; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007866:Leg / Q000033:anatomy & histology* / Q000098:blood supply*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult