title: Full field image reconstruction is suitable for high-pitch dual-source computed tomography.
abstract: OBJECTIVE
  The field of view (FOV) in high-pitch dual-source computed tomography (DSCT) is limited by the size of the second detector. The goal of this study was to develop and evaluate a full FOV image reconstruction technique for high-pitch DSCT.
  
  
  METHODS
  For reconstruction beyond the FOV of the second detector, raw data of the second system were extended to the full dimensions of the first system, using the partly existing data of the first system in combination with a very smooth transition weight function. During the weighted filtered backprojection, the data of the second system were applied with an additional weighting factor. This method was tested for different pitch values from 1.5 to 3.5 on a simulated phantom and on 25 high-pitch DSCT data sets acquired at pitch values of 1.6, 2.0, 2.5, 2.8, and 3.0. Images were reconstructed with FOV sizes of 260 × 260 and 500 × 500 mm. Image quality was assessed by 2 radiologists using a 5-point Likert scale and analyzed with repeated-measure analysis of variance.
  
  
  RESULTS
  In phantom and patient data, full FOV image quality depended on pitch. Where complete projection data from both tube-detector systems were available, image quality was unaffected by pitch changes. Full FOV image quality was not compromised at pitch values of 1.6 and remained fully diagnostic up to a pitch of 2.0. At higher pitch values, there was an increasing difference in image quality between limited and full FOV images (P = 0.0097).
  
  
  CONCLUSIONS
  With this new image reconstruction technique, full FOV image reconstruction can be used up to a pitch of 2.0.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany. andreas.mahnken@rwth-aachen.de
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
authors.forename: Thomas
authors.initials: T
authors.lastname: Allmendinger
authors.forename: Martin
authors.initials: M
authors.lastname: Sedlmair
authors.forename: Miriam
authors.initials: M
authors.lastname: Tamm
authors.forename: Sebastian D
authors.initials: SD
authors.lastname: Reinartz
authors.forename: Thomas
authors.initials: T
authors.lastname: Flohr
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001013:Aorta, Thoracic / Q000473:pathology*; D001014:Aortic Aneurysm / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D019047:Phantoms, Imaging; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*