Carbon dioxide contrast agent for CT arteriography: results in a porcine model

To test the feasibility of carbon dioxide (CO(2))-enhanced computed tomographic (CT)-arteriography in an animal model.

Five domestic swine underwent digital subtraction angiography (DSA), conventional CT angiography with iodinated contrast material, and CO(2)-enhanced CT arteriography. For each CO(2)-enhanced DSA image series, 100 mL of pressurized CO(2) was injected at 1.3 bar. CT imaging was performed according to a standardized scan protocol (2 x 32 x 0.6 mm; 120 kV, 210 mAs(eff), 330 msec gantry rotation time). Iodinated contrast material was administered intravenously according to a biphasic injection protocol. For CO(2)-enhanced CT arteriography, CO(2) was administered intraarterially via a catheter placed in the juxtarenal aorta. An injection pressure of 0.65 bar (volume flow rate, 7.5 mL/sec) was applied. Images were assessed visually by two observers on a four-point grading scale. Absolute intraarterial attenuation values were measured.

Image quality was rated to be the best for standard DSA. CO(2)-enhanced DSA was rated slightly superior to CO(2)-enhanced CT arteriography. No examination was considered to be nondiagnostic. The average multislice spiral CT (MSCT) scan duration was 7.9 sec +/- 0.6. The average amount of gas required for CO(2)-enhanced CT arteriography was 104 mL +/- 4, compared with 400 mL for CO(2)-enhanced DSA. Absolute attenuation values were significantly higher with CO(2)-enhanced CT arteriography (aorta, -928 HU +/- 39) than with standard CT angiography (490 HU +/- 40; P < .0001).

CO(2)-enhanced CT arteriography is feasible. In a porcine model, this technique is capable of depicting the aortoperipheral vessels down to the lower limb. These results warrant further studies of the diagnostic value of CO(2)-enhanced MSCT arteriography for the detection of arterial pathologic processes.