Angiocardiographic methods available for cardiac-chamber volume measurements are neither consistently accurate nor precise. To explore the capability of computed tomography for left ventricular volume measurement, Silastic casts of 24 normal human left ventricles were measured by a displacement method, a conventional angiocardiographic biplane volume method and computed tomography. The displacement method used degassing to remove air trapped in the casts; displacement was measured by Archimedes'' principle. Cast volumes measured by biplane methods displayed spread around the regression line, caused by the chamber''s irregular shape and its variations in orientation. Computed tomographic measurements were independent of chamber orientation and significantly more accurate.