Non-contrast computed tomography is comparable to contrast-enhanced computed tomography for aortic volume analysis after endovascular abdominal aortic aneurysm repair.

ABSTRACT

OBJECTIVES: To evaluate whether non-contrast computed tomography (NCCT) images are as reliable as contrast-enhanced computed tomography (CECT) images for the measurement of aortic volume (AV). MATERIALS AND METHODS: A total of 316 pairs of AVs were retrospectively measured from 316 consecutive patients, who underwent endovascular aneurysm repair (EVAR). A standardised multidetector computed tomography protocol was used to obtain precontrast, arterial and delay-phase images. A single blinded, experienced observer measured the AV from the lowest renal artery to the aortic bifurcation by means of the disc-summation method, using the precontrast and arterial-phase images. A second blinded observer measured the AV again in 16 randomly chosen cases. RESULTS: Both NCCT and CECT yielded similar AVs that were highly correlated (r(2) = 0.99; P < 0.0001). Bland and Altman analysis revealed a small bias (mean ± 2 standard deviations -0.9 ± 8 ml). The intraclass correlation coefficients (all >0.99; P < 0.0001) and low repeatability coefficients indicated that the AVs were reproducible with both methods. CONCLUSIONS: The AVs measured from NCCT images were accurate and highly reproducible compared with those from CECT images. Therefore, NCCT can be a reasonable alternative to CECT for AV assessment after EVAR. This is particularly important for patients with renal insufficiency (potentially sparing them from nephrotoxic contrast agents and unnecessary radiation) or allergy to contrast agents.