Measurement of atherosclerotic luminal irregularity and obstruction by radiographic densitometry.

This report describes a procedure to quantify stenosis and to detect enface plaques in single plane angiograms. We derived an optical density function proportional to local arterial chord length from arteriographs over a wide range of conditions. Standard radiographs were made of silicone rubber bolus used as the radiopaque medium in cadaver arteries. Replicate arterial casts filled with iodine-bearing contrast medium were radiographed for comparison. Identical atherosclerotic areas in both film sets were scanned with a microdensitometer and vessel chord lengths used to construct arterial cross sections for comparison with vessel casts. Cross-sectional areas derived from cadaver and phantom films were highly correlated with those derived from cast slices (r = 0.997). Thus, luminal cross-sectional areas were accurately estimated independent of plaque location, and accuracy of chord length measurement was +/- 0.28 mm in vessels four to 10 mm in diameter.