Determination of cardiac output with dynamic contrast-enhanced computed tomography

Cardiac output (CO) is an important diagnostic and prognostic factor in the haemodynamic evaluation of patients. The gold standard for CO measurement, thermodilution, requires an invasive right-heart catheterisation (RHC). In this pilot study we aimed to determine the accuracy of non-invasive CO determination from dynamic contrast-enhanced computed tomography (CT) compared to thermodilution. Patients who underwent diagnostic or follow-up RHC due to suspected or known pulmonary vascular disease at our department and required a thoracic CT between June 2011 and August 2012 were included. CO was determined from CT attenuation-time curves in the pulmonary artery and the ascending aorta using a dynamic contrast-enhanced CT sequence. CO determined in N = 18 patients by dynamic CT in the pulmonary artery was in very good agreement with thermodilution data (r = 0.84). Bland-Altman analysis showed a systematic overestimation of 0.7 ± 0.6 l/min compared to thermodilution. Data from the ascending aorta also showed a good correlation, but with a larger scattering of the values. The average effective dose for the dynamic investigation was 1.2 ± 0.7 mSv. CO determined with dynamic contrast-enhanced CT in the main pulmonary artery reliably predicts the values obtained by thermodilution during RHC. This non-invasive technique might provide an alternative for repeated invasive right-heart catheter investigations in the follow-up of pulmonary arterial hypertension patients.