Characterization of ureteral stents by dual-energy computed tomography: Clinical implications

Abstract

Dual-energy computed-tomography (DECT) has been suggested as the method of choice for imaging urinary calculi due to the modality’s high sensitivity for detecting stones and its capability of accurately differentiating between uric-acid (UA) and non-UA (predominantly calcium) stones. The clinical significance of the latter feature relates to the differences in management of UA vs non-UA calculi. Like calculi, ureteral stents are assigned color by the dual-energy post-processing algorithm, which may lead to improved or worsened stone visualization based on the resulting stent/stone contrast. Herein we depict the case of a nephrolithiasis patient with bilateral stents, each with different color, clearly displaying the effect of stent color on stone visualization. Further, three-dimensional reconstruction of the DECT images illustrates advantages of this enhancement compared to conventional two-dimensional computed tomography. The resulting stent/stone contrast produces an unanticipated potential advantage of DECT in patients with urolithiasis and stents and may promote improved management decision-making.

Keywords: Ureteral stent; Dual-energy computed-tomography; Dual-energy computed-tomography; Kidney stones; Nephrolithiasis

Core tip: Dual-energy computed-tomography is a recently introduced technique for imaging kidney stones. Ureteral stents are also characterized by the dual-energy (DE) algorithm and, like calculi, are assigned color. The resulting stent/stone color contrast may lead to either improved or worsened stone visualization in patients with urolithiasis and stents. This case report illustrates different DE characterization of stents based on their type, and the resulting effects on stent/stone contrast. The awareness of the DE characterization of different stent types allows for stent selection that improves stone visualization.