title: Derivation of spatial information from biplane multidirectional coronary angiograms.
abstract: Modern biplane multidirectional isocentric X-ray equipment delivers the image information necessary for spatial computations from two simultaneous 2-dimensional coronary angiographic pictures. Using the tools of analytical geometry, the spatial position of well definable points in the fields of view of the two image-intensifiers can be calculated from their corresponding projections knowing the geometrical properties of the system stands. The method developed is independent of the angle between the projections and is applicable even if hemiaxial views are used. The mathematical formulas necessary for these spatial computations are derived. By means of calculating the radiological magnification factor, the method was validated using a wire with known diameter as reference object. 360-diameter measurements of the wire filmed in 18 different simultaneous biplane projections resulted in a mean error of 3.14%. In addition, catheter measurements of routine coronary angiograms yielded a mean diameter of 2.64 +/- 0.19 mm (mean +/- SD, real diameter 2.66 mm).
  
  
  CONCLUSIONS
  Using this algorithm, a reliable determination of spatial coordinates of distinct points of interest is possible as prerequisite for absolute quantitative measurements from biplane angiograms.
mesh_terms: D000790:Angiocardiography / Q000379:methods*; D001699:Biometry; D006801:Humans; D008433:Mathematics