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.
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.
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.
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.
BMC urology. 2019 Apr 30*** epublish ***
Giuseppe Magistro, Patrick Bregenhorn, Bernhard Krauß, Dominik Nörenberg, Melvin D'Anastasi, Anno Graser, Philipp Weinhold, Frank Strittmatter, Christian G Stief, Michael Staehler
Department of Urology, Ludwig-Maximilians-University of Munich, Marchioninistrasse 15, 81377, Munich, Germany. ., Department of Radiology, Ludwig-Maximilians-University of Munich, Munich, Germany., Siemens Healthcare GmbH, Research and Development, Forchheim, Germany., Gemeinschaftspraxis Radiologie München, Munich, Germany., Department of Urology, Ludwig-Maximilians-University of Munich, Marchioninistrasse 15, 81377, Munich, Germany.