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.

A memory control unit is described, which, operating in conjunction with a special purpose digital computer, achieves real-time storage into and retrieval from computer memory of individual video images undergoing on-line digitization, processing, and reconstitution. The memory control unit is capable of rapid sequential access on up to six 16 K-word core and two 131 K-word (28-bit word) solid-state memories, achieving data transfers to or from ememory at up to 40 million 9-bit samples/s for 33 ms. The memory control unit employs a variety of data rates, and can, under program control, assemble one or more bytes into, or disassemble one or more bytes from, each memory word. The control unit can sign extend incoming data to any of four different byte lengths from any of four different byte lengths. The control unit possesses dual data busses, one dedicated to memory read operations and a second capable of either "reads from" or "writes into" memory. The eight memory modules are sequenced by a small microprogrammed control store loadable from an associated computer.

A high-fidelity video digitizer/processor extracts spatial and gray-scale information from high resolution dynamic video imagery. The 15-MHz bandwidth 60/s images(fields) are low pass filtered to minimize aliasing and digitized in real-time at 20 million samples pe second (MS/s), 9 bits/sample; sequential fields are transferred to memory, retrieved from memory after computer image processing, and reconstituted at up to 40 MS/s into 60 field/s video of 525, 875, or 1225 lines/frame (two interlaced fields). A/D and D/A converters are synchronized with memory by a high-speed interface, composed of a central data interchange (DI), and 8 rarially connected I/O ports. The DI connects the data paths of one or more ports, each communicating with one or more external devices. Separate 16-bit, 40 megawords/s, input and output data buses between each port and the DI allow data entry through any port to the DI and output from the DI through any port(s), even the same port from which the input originated. The A/D and D/A are served by a single port. Two other ports communicate with CDC 3500 and CDC 1700 computers. Yet another port controls up to two megawords of core/solid-state memory, of which 358K word may be accessed at the full data rate. Storage rates into existing memory of 40 MS/s are achieved for 16-32 ms.