Identification of cardiovascular dilution systems by contrast ultrasound.
Indicator dilution techniques permit accurate measurements of important cardiovascular parameters, such as pulmonary blood volume (PBV) and ejection fraction (EF). However, their use is limited by the need for central catheterization. Contrast ultrasonography allows overcoming this problem. PBV and EF can be measured by a dilution system identification algorithm after detection of multiple dilution curves by an ultrasound scanner. In this paper, we present a system identification method that exploits the a priori knowledge on the dilution system and finds the optimum parameters for the parametric model representing the dilution system impulse response. No subsequent model interpolation is needed. Volume measurements show accurate in-vitro results and clinical feasibility, while 50 EF measurements in patients show a 0.88 correlation coefficient with echocardiographic biplane estimates. In conclusion, adding a priori knowledge to the system identification algorithm leads to increased accuracy and robustness of the method for PBV and EF measurements.
Mischi
Massimo
M
Dept. of Electrical Engineering, Eindhoven University of Technology, The Netherlands. m.mischi@tue.nl
Jansen
Annemieke H M
AH
Korsten
Hendrikus H M
HH
D000465:Algorithms; D016275:Atrial Function / Q000502:physiology; D001811:Blood Volume Determination / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D004452:Echocardiography / Q000379:methods*; D006801:Humans; D007201:Indicator Dilution Techniques; D007267:Injections; D008168:Lung / Q000000981:diagnostic imaging* / Q000502:physiology; D045423:Microbubbles; D010743:Phospholipids / Q000008:administration & dosage; D011652:Pulmonary Circulation / Q000502:physiology; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology*; D013459:Sulfur Hexafluoride / Q000008:administration & dosage; D014465:Ultrasonics; D016276:Ventricular Function
D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride