Three-Dimensional Assessment of Renal Artery Aneurysm Growth Using Vascular Deformation Mapping

Abstract

Background

Risk factors for renal artery aneurysm (RAA) growth are poorly understood. Vascular deformation mapping (VDM) is known to accurately depict 3-dimensional (3D) growth patterns of aortic aneurysms. This study investigates the feasibility of VDM to accurately define 3D growth of RAAs and the relationship of RAA diameter alone to 3D growth.

Methods

Fifty-five RAAs having ≥2 computed tomography angiograms with ≤2.5 mm slice thickness, ≥2 months apart, were studied. RAAs were segmented and their volumes (including calcium, thrombus, lumen, and total) were determined. Change in RAA diameter (ΔDiameter) and volume (ΔVolume) over time were calculated. VDM was used to quantify 3D growth. ΔVolume and mean 3D growth were compared between RAAs having stable diameters and those with increased diameters (≥0.1 cm ΔDiameter) and the relationship between ΔDiameter, ΔVolume, and 3D growth was examined.

Results

Twenty-five of the 55 RAAs studied had successful VDM analyses. The affected patients’ mean age was 60.1 ± 8.7 years and 56% were female. One RAA was symptomatic, with no ruptures. The overall ΔDiameter was 0.86 ± 1.25 mm/year (mean CT interval of 43.1 months). Nine (36.0%) RAAs exhibited diameter increases, and when compared to the 16 stable RAAs, there were no differences in ΔVolume or 3D growth. There was no correlation of ΔDiameter with 3D growth or ΔVolume (r < 0.4, P > 0.05). RAA 3D growth strongly correlated with ΔTotal Volume (r = 0.653, P < 0.001) and ΔLumen Volume (r = 0.695, P < 0.001).

Conclusion

VDM is an accurate method for assessing RAA growth, yields additional metrics not provided by diameter alone, and provides a more comprehensive assessment of RAA morphology changes that correlate with ΔVolume.