Quantitative digital subtraction arteriography with a calibration catheter

Quantitative intraarterial digital subtraction arteriography (DSA) was performed using a calibration catheter with three distal metallic ring markers. The two outer markers were 50 mm apart, and the third marker was in the middle. Measurements of 54 vessel diameters of the abdominal aorta, renal, lumbar, and iliac arteries were performed in a comparison study with direct film arteriograms in 10 aortofemoral runoff studies. Diameter measurements were made by both the observer on hard copy DSA images and by a computer using modified semiquantitative software. Against measurements on film, which were used as the standard, deviations in measurement on digital images varied from 8 to 13% for arterial diameters <5 mm and from 2 to 6% for diameters ≥5 mm. Projectional artifacts caused 3% or less error. Knowing these variations in measurement is important in order to determine error tolerances for clinical applications. The calibration catheter serves as a convenient internal marker for DSA.