| Abstract: | True volume (y) and measured volume (x) determined from 23 right and 22 left normal human casts in four biplane angiographic positions and in their eight single-plane components were used to find the correction factor (b) by regression through the origin (y = bx). The correction factors were applied to human studies to assess the validity of the various biplane and single-plane modalities in vivo. The casts studies yield excellent correlations in both right and left biplane methods (right volumetry: 0.555 ≤ b ≤ 0.708, 0.917 ≤ r ≤ 0.954, 4.10 ≤ SEE ≤ 6.01 left volumetry: 0.748 ≤ b ≤ 0.825, 0.974 ≤ r ≤ 0.982, 4.81 ≤ SEE 5.79). Good results were obtained with single-plane volumetries as well (right volumetry: 0.316 ≤ b ≤ 0.887, 0.750 ≤ r ≤ 0.917, 10.75 ≤ SEE ≤ 18.96; left volumetry: 0.728 ≤ b ≤ 0.881, 0.897 ≤ r ≤ 0.976, 5.73 ≤ SEE ≤ 11.97). The correction factors for the single-plane studies depend much more strongly on the spatial position relative to the radiographic system, particularly in the case of the right ventricular volumes. Thus, the application of the appropriate correction factors is mandatory. The human studies (141 left and 60 right volumetric studies in various single-plane and biplane projections) showed a larger scatter of single-plane values, more pronounced for the right ventricle. In certain disease conditions, single plane volumetric studies using cast-derived correction factors cannot be used to obtain meaningful results. Correction factors for the following single or biplane mode volumetry are presented for the first time: biplane hepatoclavicular view (right and left ventricle), biplane long axial oblique view (right ventricle), and their single-plane components; lateral and 60° Left Anterior Oblique (LAO) single plane for the left-sided measurements, Postero-Anterior (PA), lateral, and 60° LAO for the single-plane right-sided calculations. |
