MDCT of Right Ventricular Function: Comparison of Right Ventricular Ejection Fraction Estimation and Equilibrium Radionuclide Ventriculography, Part 1

Abstract

OBJECTIVE. The aim of this study was to calculate right ventricular ejection fraction by use of ECG-gated MDCT and to compare the results with those of equilibrium radionuclide ventriculography. SUBJECTS AND METHODS. Forty-nine consecutively examined patients (30 men, 19 women; mean age, 59 years) with known or suspected right ventricular dysfunction secondary to bronchopulmonary (n = 30) or pulmonary vascular (n = 19) disease underwent ECG-gated 16-MDCT angiography of the heart (rotation time, 0.42 second; 120 kV; 300 mAs; collimation, 12 × 0.75 mm; pitch, 0.2) after CT angiographic examination of the entire thorax according to a standard protocol. Biphasic administration of a 30% contrast agent was systematically performed (phase 1, 90 mL at 3 mL/s; phase 2, 30 mL at 1.5 mL/s); no patient received additional medication. Right ventricular ejection fraction was calculated after two reviewers in consensus determined the reconstruction windows and segmentation of the right ventricular cavity on a series of diastolic and systolic short-axis images. The results were compared with those of equilibrium radionuclide ventriculography. RESULTS. At data acquisition, the mean (± SD) heart rate of the study group was 82 ± 13.87 beats per minute (BPM) (range, 51-115 BPM). ECG showed a sinus rhythm in 30 (61%) of the patients and irregular cardiac rhythm in 19 (39%) of the patients. Agreement between the two techniques was estimated by intraclass correlation coefficient (0.77), the method of Bland and Altman (limits of concordance, -14.9 and 13.7), and percentage of variability between two measurements expressed by mean absolute percentage error (12.1%). The estimated effective dose for heart examination was 7.48 mSv with CT and 5 mSv with scintigraphy. The mean effective dose for the chest and heart CT examinations was 11.64 mSv. CONCLUSION. Right ventricular ejection fraction can be reliably estimated with 16-MDCT in unselected patients.