Which of the following equations best describes stroke volume by Doppler echocardiography?

Prepare for the Echocardiography Techniques III Exam with flashcards and multiple choice questions. Each question includes detailed explanations. Get ready for your certification!

Stroke volume measured by Doppler echocardiography is calculated from how much blood moves through the left ventricular outflow tract in one heartbeat. The formula uses the cross-sectional area of the LVOT (CSA) times the velocity-time integral (VTI) of flow through that tract during systole. The LVOT CSA is derived from its diameter as CSA = π × (D/2)², giving a square-centimeter area. The VTI is the distance the blood column travels during systole, obtained by tracing the Doppler velocity curve; it is measured in centimeters. Multiplying CSA (cm²) by VTI (cm) yields stroke volume (cm³ or mL) because volume is area times distance. This is the direct, Doppler-based method to estimate SV. Other formulas either mix in heart rate (which would address cardiac output, not stroke volume) or use relationships involving EF and LVEDV that aren’t the Doppler measurement of flow through the LVOT.