Optimal contrast medium injection protocols for the depiction of the Adamkiewicz artery using 64-detector CT...

To determine the optimal contrast medium injection protocol for demonstrating the Adamkiewicz artery (AKA) using 64-detector CT angiography (CTA).

CTA was performed using 64-detector CT. The study population consisted of 80 patients (mean age 67.2 years) with aortoiliac diseases. In the first 60 patients 540 mg I/kg body weight was administered over 25s. The patients were randomly assigned to three protocols with imaging started at 15 (protocol A-1), 18 (A-2), or 21s (A-3) after triggering (threshold 150 HU). The other 20 received 720 mg I/kg body weight with an imaging delay of 18s (protocol B). Two radiologists evaluated the presence of the AKA and measured the attenuation of the aorta and AKA.

Aortic enhancement was 360.4, 348, 279.3, and 372 HU for protocols A-1, A-2, A-3, and B, respectively. There was no significant difference between the A-1 and A-2 protocols (Tukey-Kramer test, p=0.73); however, aortic enhancement was significantly lower in A-3 than A-1 and A-2 (p<0.01). There was no significant difference between A-2 and B (p=0.40). AKA attenuation was 69.3, 91.9, 94.6, and 105.4 HU for protocols A-1, A-2, A-3, and B, respectively. There was no significant difference between the A-2 and A-3 protocols (p=0.91); however, AKA attenuation was significantly lower with A-1 than A-2 or A-3 (p=0.01). AKA attenuation was significantly lower with A-2 than B (p=0.03) and there was a significant difference between A-2 (50%) and B (95%) in the depiction of the hairpin configuration of the AKA (p=0.02).

For the demonstration of the AKA at CTA, the optimal protocol used an imaging delay of 18s after triggering and an iodine dose of 720 mg I/kg body weight.