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Virtual Monoenergetic Images From a Novel Dual-Layer Spectral Detector Computed Tomography Scanner in Portal Venous Phase

Adjusted Window Settings Depending on Assessment Focus Are Essential for Image Interpretation

Hickethier, Tilman*; Iuga, Andra-Iza*; Lennartz, Simon*; Hauger, Myriam*; Byrtus, Jonathan*; Luetkens, Julian A.; Haneder, Stefan*; Maintz, David*; Doerner, Jonas*

Journal of Computer Assisted Tomography: May/June 2018 - Volume 42 - Issue 3 - p 350–356
doi: 10.1097/RCT.0000000000000711
Abdominal Imaging

Objective We aimed to determine optimal window settings for conventional polyenergetic (PolyE) and virtual monoenergetic images (MonoE) derived from abdominal portal venous phase computed tomography (CT) examinations on a novel dual-layer spectral-detector CT (SDCT).

Methods From 50 patients, SDCT data sets MonoE at 40 kiloelectron volt as well as PolyE were reconstructed and best individual window width and level values manually were assessed separately for evaluation of abdominal arteries as well as for liver lesions. Via regression analysis, optimized individual values were mathematically calculated. Subjective image quality parameters, vessel, and liver lesion diameters were measured to determine influences of different W/L settings.

Results Attenuation and contrast-to-noise values were significantly higher in MonoE compared with PolyE. Compared with standard settings, almost all adjusted W/L settings varied significantly and yielded higher subjective scoring. No differences were found between manually adjusted and mathematically calculated W/L settings.

Conclusions PolyE and MonoE from abdominal portal venous phase SDCT examinations require appropriate W/L settings depending on reconstruction technique and assessment focus.

From the *Institute of Diagnostic and Interventional Radiology, University Hospital of Cologne, Cologne; and

Institute of Diagnostic and Interventional Radiology, University of Bonn, Bonn, Germany.

Received for publication September 14, 2017; accepted November 27, 2017.

Correspondence to: Tilman Hickethier, University Hospital of Cologne, Kerpener Str. 62, 50937 Köln, Germany (e-mail:

M.H. was supported by the Koeln Fortune Program/Faculty of Medicine, University of Cologne, Cologne, Germany. D.M. is on the speaker's bureau for Philips Healthcare. For the remaining authors, no conflicts of interest were declared.

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