title: [Quantification of left ventricular function and mass in dual-source CT (DSCT).].
abstract: OBJECTIVE
  To evaluate the interobserver agreement in quantifying left ventricular function and mass and to assess the accuracy of conventional manual contour tracing compared to semiautomatic segmentation analysis software.
  
  
  METHODS
  Twenty consecutive subjects who underwent cardiac DSCT with retrospective ECG-gating were included. Two different multiphase image reconstructions were done in 5% steps throughout the entire cardiac cycle (0-95% of the R-R interval) with effective slice thickness of 1mm in the axial plane and 8mm in the short-axis orientation. Left ventricular function and mass were calculated by two independent observers, tracing endocardial and epicardial borders manually and using a semiautomatic software tool (Circulation II, Siemens). Ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), cardiac output (CO), and myocardial mass were evaluated by two independent observers blind to each other's assessments. The interobserver agreement and the reliability of the different segmentation methods were calculated. The time required for manual contouring and semiautomatic contour tracing was also registered.
  
  
  RESULTS
  We found an excellent correlation (r>0.94; p<0.05) between the two independent observers for the quantification of left ventricular function and mass. Left ventricular functional parameters derived from semiautomatic contour software and conventional manual tracing method were not significantly different (p>0.05). The semiautomatic contour detection algorithm overestimated LV mass significantly compared with the manual contouring method (mean difference 29.45+/-1.64g; p<0.05). The time needed to calculate these parameters with the semiautomatic tool was significantly lower (248.85+/-99.8s) than with manual contouring (452.7+/-73.92s) (p<0.05).
  
  
  CONCLUSIONS
  Interobserver agreement for quantifying left ventricular function and mass using DSCT is excellent. Despite overestimating left ventricular mass, the semiautomatic software tool allows cardíac parameters to be quantified with the same reliability as the conventional manual method in half the time.
authors.affiliation: Servicio de Radiología, Clínica Universidad de Navarra, Pamplona, España.
authors.forename: M
authors.initials: M
authors.lastname: Arraiza
authors.forename: G
authors.initials: G
authors.lastname: Bastarrika
authors.forename: B
authors.initials: B
authors.lastname: Zudaire
authors.forename: J
authors.initials: J
authors.lastname: Pueyo
authors.forename: A
authors.initials: A
authors.lastname: Villanueva
mesh_terms: D057791:Cardiac Imaging Techniques; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009929:Organ Size; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data; D016277:Ventricular Function, Left