BINARY RECONSTRUCTION OF THE HEART CHAMBERS FROM BIPLANE ANGIOGRAPHICIMAGE SEQUENCES

The aim of this work is the three dimensional (3-D) reconstruction of the left or right heart chamber from digital biplane angiograms, The a pproach used, the binary reconstruction, exploits the density informat ion of subtracted ventriculograms from two orthogonal views in additio n to the ventricular contours, The ambiguity of the problem is largely reduced by incorporating a priori knowledge of human ventricles, A mo del-based reconstruction program Is described that is applicable to ro utinely acquired biplane ventriculographic studies, Prior to reconstru ction, several geometric and densitometric imaging errors are correcte d, The finding of corresponding density profiles and anatomical landma rks is supported by a biplane image pairing procedure that takes the m ovement of the gantry system into account. Absolute measurements are b ased on geometric isocenter calibration and a slice-wise density calib ration technique, The reconstructed ventricles allow 3-D visualization and regional. wall motion analysis independently of the gantry settin g. The method is applied to clinical angiograms and tested in left- an d right-ventricular phantoms yielding a well shape conformity even wit h few model information, The results indicate that volumes of binary r econstructed ventricles are less projection-dependent compared to volu me data derived by purely contour-based methods, A limitation is that the heart chamber must not be superimposed by other dye-filled structu res in both projections.