Comparison of 3-Dimensional Ultrasound and Computed Tomography for Imaging of Abdominal Aortic Aneurysms

Three-dimensional ultrasound (3D US) is emerging as a novel imaging method for abdominal aortic aneurysms (AAAs) as it creates a low-cost 3D AAA overview without harmful radiation and nephrotoxic contrast agents, as opposed to conventional imaging. 3D US can be used with a non-nephrotoxic contrast agent (3D-CEUS) for lumen delineation. This study aims to compare 3D US and 3D-CEUS using a commercially available 3D US system against contrast-enhanced computed tomography (CTA).

For twenty AAA patients, the total AAA was segmented for all 3 modalities, and the lumen was segmented in the 3D-CEUS and CTA scans. The CTA segmentations were registered onto each 3D (CE)US segmentation, and evaluation metrics were computed, including the volumes, average surface distance, sensitivity, precision, and Dice score.

3D US and 3D-CEUS scans were feasible in all patients. Lumen volumes were significantly larger on 3D-CEUS compared to CTA (94 versus 70 mL, p < .001). The total AAA volumes were significantly smaller on 3D US compared to CTA (142 versus 165 mL, p = .002), and comparable on 3D-CEUS (176 versus 165 mL, p = .433). The Dice scores were overall acceptable, ranging from 0.82 to 0.88, and the average surface distances were 2.5 mm.

This study demonstrated the feasibility of 3D US and 3D-CEUS for AAA imaging with good correspondence to CTA. Addition of the contrast agent increased agreement of volume measurements. 3D US facilitated retrospective offline AAA assessment, which is a major added value compared to 2D US. For now, 3D US already seems a promising imaging modality, which has to be proven in a large-scale study.