title: Comparison of ECG-gated versus non-gated CT ventricular measurements in thirty patients with acute pulmonary embolism.
abstract: OBJECTIVE
  To prospectively compare cardiac ventricular measurements from non-gated CT and end-diastolic ECG-gated CT in patients with acute pulmonary embolism (PE).
  
  
  METHODS
  With institutional review board approval, 30 adult patients (16 female, mean age = 56 years, range = 26-77 years) underwent ECG-gated cardiac CT within 36 h of their CT diagnosis of acute PE to assess the right ventricle (RV). The axial and reformatted four-chamber ventricular diameters, areas and volumes were measured for both the non-gated CT and the ECG-gated CT in end-diastole and end-systole. Spearman's rank correlation coefficient (RCC) was calculated to compare measurements from the non-gated CT to the gated end-diastolic measurements. The median absolute differences between the gated and non-gated measurements relative to the gated measurements were provided to summarize the degree to which the two measurements differ. A statistical model was constructed to test for potential improvement in specificity for the prediction of 30-day mortality after acute PE using right ventricular measurements from ECG-gated CT versus non-gated CT.
  
  
  RESULTS
  The RCC (0.90 confidence interval) for non-gated and ECG-gated end-diastolic four-chamber and axial RV/LV diameter ratios were 0.83 (0.68-0.90) and 0.88 (0.74-0.95). The median absolute percent differences suggested a high degree of concordance between gated and non-gated measurements. The statistical model predicted that measuring the RV/LV diameter ratio from end-diastole using ECG-gated CT rather than non-gated CT would yield a potential improvement in specificity for death after PE of 0.035 (0.020-0.060) for axial diameter ratios and 0.035 (0.020-0.055) for four-chamber diameter ratios.
  
  
  CONCLUSIONS
  The benefit from a separate ECG-gated CT scan for the evaluation of RV ventricular diameter, area, and volume measurements is minimal and does not justify its routine clinical use.
authors.affiliation: Department of Radiology and Harvard Medical School, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lu
authors.forename: Tianxi
authors.initials: T
authors.lastname: Cai
authors.forename: Hale
authors.initials: H
authors.lastname: Ersoy
authors.forename: Amanda G
authors.initials: AG
authors.lastname: Whitmore
authors.forename: Noah A
authors.initials: NA
authors.lastname: Levit
authors.forename: Samuel Z
authors.initials: SZ
authors.lastname: Goldhaber
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Rybicki
mesh_terms: D000328:Adult; D000368:Aged; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging*