Dynamic spatial reconstructor

The first experienced sample of such type system is developed in department of biodynamic researches of clinic Mayo. It is referred to as Dynamic Spatial Reconstructor [16]. 

In Dynamic Spatial Reconstructor at the expense of use 2D matrix of detectors there was the opportunity to use a divergent cone beam of source emission. This system had a number of lacks. In particular the number of projections is rigidly limited by the number of x-ray sources. The dispersion of source emission results in errors of data collected.. However the system confirmed basic advantages of application of conic beams and 2D matrices of detectors for collecting information about 3D object. 

At present it seems that the sequence of geometries of the LV obtained at various stages of the cardiac cycle by tomography (via the DSR - Dynamic Spatial Reconstructor) at the Mayo Clinic (Ritman etal., 1980) are the best available 3-D reconstructions of the ventricle. Though this technique is not yet widely spread, it would be recommended to use the DSR geometries in the FE analysis in view of the importance of the exact configuration of the LV. 

Accurate quantitation of the shape and dimensions of all cardiac chambers and myocardium is possible with the Dynamic Spatial Reconstructor (DSR). Generally a single bolus injection of approximately 2ml/kg roentgen contrast agent in the right atrium will provide information of the chamber volumes and myocardial mass within 5% of the actual value. The detailed shape of the chambers and myocardium facilitates evaluation of heart deformed by complex congenital heart disease or myocardial infarction (aneurysm). 

In response to this problem we built the Dynamic Spatial Reconstructor (DSR) which is illustrated in Figure 1 (Kinsey et ai, 1980 Ritman et al, 1980). This artist s rendition of the machine shows a subject lying horizontally along the axis of rotation of a circular drum. To one half of the perimeter of this drum are attached 14 television cameras and on the opposite half of the drum are attached 14 W-ray tubes. By rapid sequential electronic actuation of these X-ray tubes and... 

Figure L Artist s concept of Dynamic Spatial Reconstructor. Cutaway diagram shows a patient lying on a table that is surrounded by a semicircular array of 14 X-ray tubes (lower half) and television cameras (upper half). At the patient s feet is a large bearing that enables the gantry to be rotated continuously around the patient (Schwartz etaiy 1983b).

Figure 14. Correlation between left ventricular muscle volume estimated by Dynamic Spatial Reconstructor (DSR) (ordinate) and by postmortem measurements (abscissa). Volume of myocardium estimated by DSR is plotted for three separate measurements for each dog. Regression line was calculated using average of the three measurements by DSR and volume by postmortem study. The eight dogs used (2.5—32.5 kg) had morphine-pentobarbital anesthesia, end diastole, 0.06 s aperture, and superior vena cava injection of Iml/kg lohexol (Iwasaki etai, 1984a).

Behrenbeck T, Kinsey JH, Harris LD, Robb RA, Ritman EL (1982) Three-dimensional spatial, density, and temporal resolution of the Dynamic Spatial Reconstructor. J Comput Assist Tomogr 6 1138-1147... 

Iwasaki T, Sinak LJ, Hoffman EA, Robb RA, Harris LD, Bahn RC, Ritman EL (1984a) Mass of left ventricle myocardium estimated with the Dynamic Spatial Reconstructor. Am J Physiol Heart and Circulatory Physiol 15 H138-H142... 

Robb RA, Lent AH, Gilbert BK, Chu A (1980) The Dynamic Spatial Reconstructor a computer tomography system for high-speed simultaneous scanning of multiple cross sections of the heart. J... 

Robb RA, Hoffman EA, Sinak LI, Harris LD, Ritman EL. High-speed three-dimensional X-ray computed tomography the dynamic spatial reconstructor. Proc IEEE 1983 71 308-319. 

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