Contrast echocardiography for pulmonary blood volume quantification.
Pulmonary blood volume quantification is important both for diagnosis and for monitoring of the circulatory system. It requires employment of transpulmonary indicator dilution techniques, which are very invasive due to the need for double catheterization. This paper presents a new minimally invasive technique for blood volume quantification. An ultrasound contrast agent bolus is injected peripherally and detected by an ultrasound transducer in the central circulation. Several echocardiographic views permit simultaneous detection of contrast in different cardiac cavities and central vessels, and acoustic backscatter measurements produce multiple indicator dilution curves (IDCs). Contrast mean-transit-time differences are derived from the IDC analysis and multiplied times cardiac output for the assessment of blood volumes between different detection sites. For pulmonary blood volume estimates, the right ventricle and the left atrium IDCs are measured. The mean transit time of the IDC is estimated by specific modelling. The Local Density Random Walk and the First Passage Time models were tested for IDC interpolation and interpretation. The system was validated in vitro for a wide range of flows. The results show very accurate volume measurements. The volume estimate determination coefficient is greater than 0.999 for both model fits. A preliminary study in patients shows promising results.
Eindhoven University of Technology, Eindhoven, The Netherlands. m.mischi@tue.nl
Massimo
M
Mischi
Ton A
TA
Kalker
Erik H
EH
Korsten
D000465:Algorithms; D001783:Blood Flow Velocity; D001810:Blood Volume / Q000502:physiology*; D001811:Blood Volume Determination / Q000379:methods*; D003198:Computer Simulation; D003287:Contrast Media; D004452:Echocardiography / Q000295:instrumentation / Q000379:methods*; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007201:Indicator Dilution Techniques; D008955:Models, Cardiovascular; D019047:Phantoms, Imaging; D011652:Pulmonary Circulation / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D003287:Contrast Media