Limitations of Quantitative Determination of Left Ventricular Volume by Multiscan Echocardiography

Abstract

It has been shown that Multiscan Echocardiography (ME) offers unique possibilities for qualitative assessment of left ventricular (LV) size, shape and dynamic geometry. From the long-axis cross-section of the LV, quantitative measurements of volumes with the area length method appear a logical consequence. End-diastolic and end-systolic LV volumes calculated from ME LV cross-sections and from quantitative single plane angio were compared in 50 patients (r=0.61, and 0.74 respectively). The reasons for this unsatisfactory correlation have been studied and limitations applying to two-dimensional systems analyzed. These include: (1) the angular dependence of reflectivity (poor apical visualisation); (2) the limited dynamic range of oscilloscope display; and (3) the limited resolution resulting in erroneous display of structures off the main axis. Although the physical principle behind this beam width effect is the same for single element (SE) as ME, the appearance on the display is different. “Spurious echoes” of structures occur in SE whereas a “verticalization effect” of structures takes place in ME. This effect can not only introduce interpretation errors but is especially cumbersome for detection of the endocardium.