Real-time, three-dimensional echocardiography: feasibility of dynamic right ventricular volume measurement with saline contrast.
BACKGROUND
The asymmetry and complex shape of the right ventricle have made it difficult to determine right ventricular (RV) volume with 2-dimensional echocardiography. Three-dimensional cardiac imaging improves visualization of cardiac anatomy but is also complex and time consuming. A newly developed volumetric scanning system holds promise of obviating past limitations.


METHODS
Real-time, transthoracic 3-dimensional echocardiographic images of the right ventricle were obtained with a high-speed volumetric ultrasound system that uses a 16:1 parallel processing schema from a 2.5 MHz matrix phased-array scanner to interrogate an entire pyramidal volume in real time. The instrumentation was used to measure RV volume in 8 excised canine hearts; dynamic real-time 3-dimensional images were also obtained from 14 normal subjects.


RESULTS
Three-dimensional images were obtained in vitro and in vivo during intravenous hand-agitated saline injection to determine RV volumes. The RV volumes by real-time 3-dimensional echocardiography are well correlated with those of drained in vitro (y = 1.26x - 9.92, r = 0.97, P <.0001, standard error of the estimate = 3.26 mL). For human subjects, the end-diastolic and end-systolic RV volumes were calculated by tracing serial cross-sectional, inclined C scans; functional data were validated by comparing the scans with conventional 2-dimensional echocardiographic indexes of left ventricular stroke volume.


CONCLUSIONS
These data indicate that RV volume measurements of excised heart by real-time 3-dimensional echocardiography are accurate and that beat-to-beat RV quantitative measurement applying this imaging method is possible. The new application of real-time 3-dimensional echocardiography presents the opportunity to develop new descriptors of cardiac performance.
Ota
T
T
Division of Medicine and Biomedical Engineering, The Center for Emerging Cardiovascular Technologies, Duke University, Durham, NC, USA.
Fleishman
C E
CE
Strub
M
M
Stetten
G
G
Ohazama
C J
CJ
von Ramm
O T
OT
Kisslo
J
J
D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage*; D004285:Dogs; D019560:Echocardiography, Three-Dimensional; D005240:Feasibility Studies; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007275:Injections, Intravenous; D012016:Reference Values; D015203:Reproducibility of Results; D012965:Sodium Chloride / Q000008:administration & dosage; D016278:Ventricular Function, Right / Q000502:physiology*
D003287:Contrast Media; D012965:Sodium Chloride