title: Dual-source computed tomography for assessing cardiac function: a phantom study.
abstract: OBJECTIVE
  To investigate the influence of heart rate and temporal resolution on the assessment of global ventricular function with dual-source computed tomography (DSCT).
  
  
  METHODS
  A dynamic cardiac phantom was repeatedly scanned with a DSCT scanner applying a standardized scan protocol at different heart rates, ranging from 40 to 140 bpm. Images were reconstructed with monosegmental and bisegmental algorithms using data from a single source and from both sources. Ventricular volumes and ejection fraction (EF) were computed by semiautomated analysis. Results were compared with the phantom's real volumes. Interscan, intraobserver, and interobserver variability were calculated.
  
  
  RESULTS
  For single-source data reconstruction temporal resolution was fixed to 165 milliseconds, whereas dual-source image reconstructions resulted in a temporal resolution of 83 milliseconds (monosegmental) and 67.7+/-14.2 milliseconds (bisegmental), respectively. In general, deviation from the phantom's real volumes was less with dual-source data reconstruction when compared with single-source data reconstruction. Comparing dual-source data reconstruction with single-source data reconstruction, the percent deviation from the phantom's real volumes for EF was 0.7% (monosegmental), 0.7% (bisegmental), and 4.3% (single source), respectively. There was no correlation between heart rate and EF for dual-source data reconstruction (r=-0.168; r=-0.157), whereas a relevant correlation was observed for single-source data reconstruction (r=-0.844). Interscan, intraobserver, and interobserver variability for EF were 1.4%, 0.9%, and 0.3%, respectively.
  
  
  CONCLUSIONS
  DSCT allows reliable quantification of global ventricular function independent of the heart rate. Multisegmental image reconstruction is not needed for DSCT assessment of global ventricular function.
authors.affiliation: Department of Diagnostic Radiology, University Hospital, RWTH-Aachen University, Aachen, Germany. mahnken@rad.rwth-aachen.de
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Mahnken
authors.forename: Herbert
authors.initials: H
authors.lastname: Bruder
authors.forename: Christoph
authors.initials: C
authors.lastname: Suess
authors.forename: Georg
authors.initials: G
authors.lastname: Mühlenbruch
authors.forename: Philipp
authors.initials: P
authors.lastname: Bruners
authors.forename: Christian
authors.initials: C
authors.lastname: Hohl
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Guenther
authors.forename: Joachim E
authors.initials: JE
authors.lastname: Wildberger
mesh_terms: D000465:Algorithms; D006321:Heart / Q000502:physiology*; D006339:Heart Rate; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D019047:Phantoms, Imaging; D010865:Pilot Projects; D013318:Stroke Volume; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*; D016276:Ventricular Function