Rotating step-wedge technique for extraction of luminal cross-sectional area information from single plane coronary...

A cinedensitometric technique for extracting luminal cross-sectional area information is described. Linearization of cineangiographic gray scale with contrast medium thickness was achieved by use of a rotating step-wedge technique. Accuracy of the technique was estimated by filming, over the heart, contrast medium-filled cylindrical phantoms of diameters simulating a wide range of stenosis of a coronary artery. Expressed as (per cent stenosis), a mean error of 3.6 +/- 3.4 per cent between measured and known values of 72 cross-sectional area ratios was found (r = 0.981), and was significantly less than a 7.6 +/- 6.5 per cent error associated with area ratios derived from diameter measurements alone (p less than 0.005).