AUR Memorial Award. Determinants of contrast enhancement for intravenous digital subtraction angiography.

Mask mode intravenous digital subtraction angiography (IV-DSA) image quality is directly dependent on the arterial time-concentration curve peak and width produced by contrast media. Curves with high peak iodine concentration produce excellent difference images. Curves that are narrow appear and disappear quickly and minimize movement artifacts. Using a noninvasive x-ray technique for quantitative measurement of contrast media time-concentration curve parameters and cardiac output, three experimental data bases were analyzed. From the analyses, equations defining curve peak and width were derived and validated. Width is proportional to central blood volume and inversely proportional to cardiac output. Peak is proportional to the quantity of contrast media injected and inversely proportional to central blood volume. Hypertonic contrast media increases central blood volume and lowers curve peak. Optimal contrast media for IV-DSA is low in concentration and high in volume. In addition, low concentration contrast media may be more comfortable for the patient causing fewer motion artifacts.