Assessment of human right ventricular cast volume by CT and angiocardiography

Angiocardiographic methods available for cardiac chamber volume measurements have been shown to be less accurate although more practical than CT for the evaluation of the LV. To explore the capability of CT for RV volume measurements, silastic casts of seven normal RV were measured by a displacement method, conventional angiocardiographic biplane methods, and CT. The displacement method used degassing beneath vacuum to remove air trapped in the casts, and the actual volumes, which varied between 62 and 188 cc, were measured by Archimedes' principle. Cast volumes measured by biplane angiogram methods displayed a varying degree of spread around the regression line, caused by the chamber's irregular shape and its variation in orientation relative to the x-ray beams. CT measurements were in all aspects significantly more accurate.