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. 2019 Apr 30;19(1):29.
doi: 10.1186/s12894-019-0459-3.

Optimized management of urolithiasis by coloured stent-stone contrast using dual-energy computed tomography (DECT)

Giuseppe Magistro  1 , Patrick Bregenhorn  2 , Bernhard Krauß  3 , Dominik Nörenberg  3 , Melvin D'Anastasi  3 , Anno Graser  4 , Philipp Weinhold  5 , Frank Strittmatter  5 , Christian G Stief  5 , Michael Staehler  5
Affiliations

Optimized management of urolithiasis by coloured stent-stone contrast using dual-energy computed tomography (DECT)

Giuseppe Magistro et al. BMC Urol. .

Abstract

Background: We analysed in vitro the appearance of commonly used ureteral stents with dual-energy computed tomography (DECT) and we used these characteristics to optimize the differentiation between stents and adjacent stone.

Methods: We analysed in vitro a selection of 36 different stents from 7 manufacturers. They were placed in a self-build phantom model and measured using the SOMATOM® Force Dual Source CT-Scanner (Siemens, Forchheim, Germany). Each sample was scanned at various tube potentials of 80 and 150 peak kilovoltage (kVp), 90 and 150 kVp and 100 and 150 kVp. The syngo Post-Processing Suite software program (Siemens, Forchheim, Germany) was used for differentiation based on a 3-material decomposition algorithm (UA, calcium, urine) according to our standard stone protocol.

Results: Stents composed of polyurethane appeared blue and silicon-based stents were red on the image. The determined appearances were constant for various peak kilovoltage (kVp) values. The coloured stent-stone-contrast displayed on DECT improves monitoring, especially of small calculi adjacent to indwelling ureteral stents.

Conclusion: Both urinary calculi and ureteral stents can be accurately differentiated by a distinct appearance on DECT. For the management of urolithiasis patients can be monitored more easily and accurately using DECT if the stent shows a different colour than the adjacent stone.

Keywords: Dual-energy computed tomography; Stent-stone-contrast; Stone disease; Urolithiasis.

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The authors declare that they have no competing interests.

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Figures

Fig. 1
Fig. 1
A container was filled with water at body temperature (36 °C). Stents were fixed with clips at both ends and spanned throughout the phantom model for measurements
Fig. 2
Fig. 2
a. Results acquired for various tube potentials (80/150 kVp; 90/150 kVp; 100/150 kVp). Respective Hounsfield units (HU) were measured and plotted. Stents above the cut-off of 1,15 appeared blue and samples below the cut-off appeared red. Reference values for known stone types are depicted as well. Polyurethane-based samples were blue, silicone-based stents were red. b. A pure calcium oxalate monohydrate stone of 2 mm (blue) was affixed to a blue and red stent on DECT. The enhanced stent-stone-contrast obtained for the red stent allows clear differentiation of the stone from the adjacent stent. For the blue stent a contour irregularity of the stent is indicative of stone presence, better displayed on coronal than sagittal images
See this image and copyright information in PMC

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