Comparison of ECG-gated versus non-gated CT ventricular measurements in thirty patients with acute pulmonary embolism.
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.
Lu
Michael T
MT
Department of Radiology and Harvard Medical School, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115, USA.
Cai
Tianxi
T
Ersoy
Hale
H
Whitmore
Amanda G
AG
Levit
Noah A
NA
Goldhaber
Samuel Z
SZ
Rybicki
Frank J
FJ
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*