title: Centroid-based maximum intensity projections.
abstract: OBJECTIVE
  Maximum intensity projection (MIP) is a three-dimensional visualization technique for tomographic angiograms. While conventional MIPs display contralateral vascular anatomy, this study uses centroid calculations to remove this information. It is necessary to provide accurate, unambiguous vessel depiction and identical projections regardless of slice orientation.
  
  
  METHODS
  A mathematical model was formed using parameters from clinical images of the head. The vessel widths from the resulting projections were measured and compared with the model. To test the consistency of the projection process, a clinical image set was reformatted and projections of the same view were compared.
  
  
  RESULTS
  The vessel widths were smaller than in the model while varying interpolation and noise. Similar projection views were generated for all slice orientations, but some misalignment was present.
  
  
  CONCLUSIONS
  Vessel width is affected by the ray's path length and interpolation method. Some slight misalignment is present because the reformatting process alters the centroid calculations.
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA. dave cash@vanderbilt.edu
authors.forename: David M
authors.initials: DM
authors.lastname: Cash
authors.forename: Michelle G
authors.initials: MG
authors.lastname: Palmisano
authors.forename: Robert L
authors.initials: RL
authors.lastname: Galloway
mesh_terms: D002533:Cerebral Angiography / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008962:Models, Theoretical; D014057:Tomography, X-Ray Computed / Q000379:methods*