The left apical 4-chamber image is used for one measurement and for a “biplane” estimate (that averages values from orthogonal planes), either the right parasternal long-axis image (the authors' preference) or the left apical 2-chamber view (shown here) is also measured. […] Either a biplane (Simpson) method of discs or a 3D volumetric rendering is used for LV volume measurements in human echocardiography laboratories.
2021, John D. Bonagura, Virginia Luis Fuentes, “Echocardiography”, in John S. Mattoon, Rance K. Sellon, Clifford R. Berry, editors, Small Animal Diagnostic Ultrasound, 4th edition, St. Louis, MO: Elsevier, page 290