Evaluation of stroke volume and ventricular mass in a fetal heart model: a novel four-dimensional echocardiographic analysis.
OBJECTIVE
This study aimed to assess the feasibility and accuracy of nongated four-dimensional echocardiography (4DE) for determining left ventricular (LV) stroke volume (SV) and mass in a fetal heart-sized LV model.


METHODS
A balloon was inserted into the LV of 20 fresh rabbit hearts and attached to a calibrated pulsatile pump. Ten hearts retaining the right ventricle were imaged in Group A. Ten hearts without the right ventricles (RVs) attached were imaged in Group B. Nongated 4D volumes were obtained using a Philips iU-22 system with an X6-1 matrix probe at SVs ranging from 1 to 5 mL at increments of 1 mL. At each SV, the volume displacement of the heart was measured at end-systole and end-diastole. Mass was determined by displacement at the conclusion of the experiment.


RESULTS
The images were analyzed offline by manually tracing endocardial and epicardial boundaries of stacked contours. An excellent correlation in SV and mass between echo-derived values and displacement values was demonstrated and accompanied by high coefficients of determination (R2 ) in both groups (SV: Group A: R2 = 0.9461, Group B: R2 = 0.9811; Mass: Group A: R2 = 0.9223, Group B: R2 = 0.9602; all P < 0.001). Bland-Altman analyses showed a slight overestimation in both groups for both SV and LV mass.


CONCLUSIONS
Nongated 4DE was demonstrated to be feasible and that it could accurately define SV and ventricular mass for a fetal heart-sized LV model.
Department of Medical Ultrasound, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China; Oregon Health & Science University, Portland, Oregon.
Meihua
M
Zhu
Cole
C
Streiff
Jill
J
Panosian
David
D
Roundhill
Michael
M
Lapin
Boris
B
Tutschek
Muhammad
M
Ashraf
David J
DJ
Sahn
D000818:Animals; D019561:Echocardiography, Four-Dimensional / Q000379:methods*; D005240:Feasibility Studies; D005318:Fetal Heart / Q000000981:diagnostic imaging*; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D023421:Models, Animal; D009929:Organ Size; D011817:Rabbits; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology*
fetal echocardiography; four-dimensional echocardiography; left ventricular mass