Dynamic Three-Dimensional X-Ray Computed Tomography of the Heart, Lungs, and Circulation

Abstract

High temporal resolution, full threedimensional imaging of the heart, lungs and circulation is required for accurate basic physiological studies of the structural-tofunctional relationships of these organ systems, and for improved diagnostic evaluation atid treatment of patients inflicted with disorders of the vital life processes for which these organ systems arp responsible. Current generation CT scanners cannot provide these important capabilities due to their limited axial scan range and relatively slow scan speeds. Gated CT scan techniques to produce dynamic images of single cross sections of the heart and lungs during an "average" heart beat or respiratory cycle are based on assumptions of physiological stationarity, which is very difficult to obtain even by invasive techniques, and which almost certainly does not occur spontaneously in patients with cardiac or pulmonary disease. Reproducibility of breath-holding procedures to obtain multiple thoracic (heart) cross sections from successive scans ig similarly very difficult to achieve. And the certain non-reproducibility of injected circulatory indicators throughout the body yields CT gating techniques invalid for imaging of vascular anatomy or the simultaneous dynamic three-dimensional distribution of blood flow to, from, and within the heart, lungs, and other organ systems of the body. The SSDSR is the first known CT scanner to provide simultaneous scanning of up to 250 cross sections, that is synchronous cylindrical scanning. Consequently the full three-dimensional extent of relatively large organs like the heart can be captured in one scan procedure and stored in computer memory. The reconstructed 3-D image can then be mathematically (i.e.