The problem of accurate measurement of left ventricular shape and dimensions from multiplane roentgenographic data

Dynamic (30 to 60/sec) measurements of the 3 dimensional shape and dimensions of the ventricular epi and endocardial surfaces along with simultaneous transmural pressures are required for calculations of the changes in myocardial length:tension relationships which are required to generate the changes in chamber volumes and pressures necessary to propel the volumes of blood needed to maintain bodily functions. These relationships which cannot be obtained from biplane angiographic data are presumably a more direct index of cardiac contractility and reserve than can be derived from conventional measurements of ventricular volumes and pressures. Quite accurate 3 dimensional reconstructions of irregularly shaped nonhomogeneous structures, such as the intact heart, can be achieved if a larger number of multiplanar roentgen projections are used. 3 dimensional reconstructions of working dog ventricles by means of a high spatial and temporal resolution computer based scanning roentgen videodensitometric technique were achieved.