title: Effect of lower tube voltage on the reproducibility of right-to-left ventricular diameter ratio measurements on computed tomographic pulmonary angiography images.
abstract: OBJECTIVE
  This study aimed to evaluate the interobserver variability of right-to-left ventricular (RV/LV) diameter ratios on computed tomographic pulmonary angiographies at reduced tube potential.
  
  
  METHODS
  Consecutive computed tomographic pulmonary angiographies performed at 80 kVp for subjects weighing less than 80 kg (n = 40) and 100 kVp for those weighing 80 kg or greater (n = 40) were selected as the low peak kilovoltage cohort, with age- and sex-matched studies performed at 120 kVp forming the controls (n = 40 each). The interobserver variability in RV/LV diameter ratio on axial and 4-chamber images was evaluated.
  
  
  RESULTS
  Interobserver correlation was excellent at both reduced tube voltages (correlation coefficients, 0.81-0.91; P < 0.001). Bland-Altman plots indicated higher variability at lower peak kilovoltage, confirmed only for axial measurements by multivariate regression adjusting for body weight and ventricular ratio (β coefficient = 0.04 and 0.03, P = 0.049 and 0.022, for 80 kVp and 100 kVp, respectively).
  
  
  CONCLUSIONS
  Lower tube voltage did not affect the reproducibility of RV/LV diameter ratio on 4-chamber images; for axial measurements, the increase in variability was 3% to 4% of the average ventricular ratio.
authors.affiliation: From the Applied Imaging Science Laboratory, Department of Radiology, Brigham and Women's Hospital, Boston, MA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: George
authors.forename: Andetta R
authors.initials: AR
authors.lastname: Hunsaker
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rybicki
authors.forename: Kanako K
authors.initials: KK
authors.lastname: Kumamaru
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D017380:Hypertrophy, Right Ventricular / Q000000981:diagnostic imaging* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000209:etiology*; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult