Lower limb angiography: a prospective study comparing carbon dioxide with iodinated contrast material in 30 patients.

OBJECTIVE We prospectively compared patients' tolerance for and the usefulness of carbon dioxide (CO2) with iodinated contrast material in the study of lower limb arteries in 30 patients. SUBJECTS AND METHODS We systematically performed digital subtraction angiography with electronic injection of CO2 (injection average, 330 ml) and digital subtraction angiography with iodinated contrast material in 30 patients (20 men and 10 women; mean age, 67.5 years) suffering from lower limb ischemia. Patients were monitored for vital signs and comfort. Four reviewers subjectively evaluated vessel visibility at five levels (pelvis, thigh, knee, calf, and ankle). We used the Student's t test to evaluate the tolerance and the global examination quality. The chi-square test was used to evaluate the stratified analysis of the observers and scores of the image quality according to the anatomic level studied. Bartlett's test of equality of variances was used to compare the variances between the readers. RESULTS CO2 was less well tolerated (p < .01) than iodine was. Fifty-three percent of patients reported CO2 was equally well tolerated (53%), 40% reported more discomfort than with iodine, and 4% reported less discomfort than with iodine. Both techniques were equivalent for imaging of the iliac arteries, but CO2 performed poorly in the arteries below the knee (p << .001). CONCLUSION CO2 angiography with electronic injection proved to be less comfortable than iodinated angiography. CO2 arteriography is equivalent to iodinated arteriography for imaging the iliac arteries but imaging performance progressively degrades in the more distal arteries of the legs.