Reducing Stent-Induced Blooming Artifacts Using Virtual Monoenergetic Imaging Reconstructions in a Superficial Femoral Artery Phantom: An In-Vitro Study.

Abstract

Purpose: Spectral computed tomography derived virtual monoenergetic imaging (VMI) reconstructions have been shown to reduce stent-induced blooming artifacts thus minimizing in-stent lumen underestimation. We have investigated the use of VMI reconstructions to reduce the blooming artifact for stent markers, single and double stent configurations.

Methods: Two partially overlapping covered stents were deployed in a superficial femoral artery phantom. A conventional and twelve VMI reconstructions (40-100 keV and 120-200 keV with 10 and 20 keV increments, respectively) were created. Contrast-to-noise ratio, signal-to-noise ratio, attenuation difference between native and in-stent vessel lumen and full width at half maximum (FWHM) of the stent peaks were evaluated. The in-stent lumen diameter was measured, and the stent evaluated using a 5-point scale by three interventional radiologists.

Results: The 80-100 keV VMI reconstructions for the single stent configuration and the 140 keV VMI reconstruction for the other configurations resulted in the smallest lumen underestimation and best quality score on blooming. The underestimation was reduced from 21.5-29.1% for the conventional reconstruction to 14.1-18.6% for the optimal VMI reconstructions. No significant differences were observed in FWHM between the conventional reconstruction and the 50-200 keV VMI reconstructions.

Conclusions: VMI was found to minimize stent-induced blooming artifacts and improve in-stent lumen assessment. More stent material requires higher-energy VMI reconstructions to reduce blooming. The absence of significant differences in quantitative parameters suggests that the number of pixels affected by the blooming artifact is not reduced using VMI reconstructions.