Quantitative imaging of dynamic structure and function of the heart, lungs and circulation by computerized reconstruction and subtraction techniques

Conventional radiographic imaging techniques are not adequate for determination of the true, dynamic changes in shape and dimensions of the intact working heart, lungs and circulation which are required for accurate quantitative determination of the structure and function of these organ systems. This paper describes a computerized method for obtaining images of the dynamic spatial distribution of x-ray attenuation throughout multiple parallel cross-sectional planes bisecting the intact thorax, with 1-mm spatial resolution and 60-per-second temporal resolution, and for generating time delay video and cine displays of the spatial and temporal sequences of these cross-sectional images. Operator-interactive computer programs facilitate the dynamic display of reconstructed cross sections of the heart and lungs, with or without dynamic background subtraction, and permit calculation and display of any desired single or spatially related set of coronal, sagittal or obliquely oriented sections. Such displays permit viewing of the temporal and spatial distribution of contraction, expansion, and perfusion of these organs over their full anatomic extent in various orientations and in variable time-base modes ranging from stop-action to real-time. The results achieved with this computerized system for three-dimensional reconstruction and display of moving organs, particularly the heart, lungs, and circulation, demonstrate the potential for providing greatly improved techniques for investigation of the relationships of the dynamic three-dimensional anatomy and blood-tissue exchange properties of moving organ systems to their regional and integrated function, and ultimately for providing powerful new clinical diagnostic methods for elucidation of abnormalities of the heart, lungs and circulation in man.