Quantitative validation of cineangiographic biplane axial oblique right ventricular volume measurement

Axial cranial oblique biplane views of the right ventricle (RV) permit unique assessment of the RV outflow tract, relationship of the great vessels, and anatomy of the proximal pulmonary arteries. This view may also be useful in assessment of RV free wall and RV septal wall motion. However, the accuracy of volumes derived from biplane angiocardiography with the use of the axial cranial oblique projection has not been adequately validated or compared to conventional views. Nineteen RV animal casts whose volume was determined by water displacement were filmed in conventional posteroanterior/lateral (PA/Lat), 30-degree right anterior oblique/60-degree left anterior oblique (30 degrees RAO/60 degrees LAO) views and in angulated 35-degree right anterior oblique/55-degree left anterior oblique/30-degree cranial (35 degrees RAO/55 degrees LAO/30 degrees Cr) view. Tracings of biplane cast images were analyzed for RV volume by Simpson's rule. RV cast volume was significantly overestimated by 12.2 +/- 6.8, 6.0 +/- 5.3, and 9.3 +/- 9.5 ml in PA/Lat, 30 degrees RAO/60 degrees LAO, and 35 degrees RAO/55 degrees LAO/30 degrees Cr views, respectively. The correlation coefficient (r) and the standard error of the estimate (SEE) for true vs calculated volume was 0.96, 0.98, and 0.97, and 6.8, 5.2, and 7.3 ml, respectively, for PA/Lat, 30 degrees RAO/60 degrees LAO, and 35 degrees RAO/55 degrees LAO/30 degrees Cr views. Although there was a high correlation of angiographic volumes with true volume in all three views, the 30 degrees RAO/60 degrees LAO projection had the most ideal regression characteristics with highest r value and the lowest SEE.(ABSTRACT TRUNCATED AT 250 WORDS)