title: Noise-optimized monoenergetic post-processing improves visualization of incidental pulmonary embolism in cancer patients undergoing single-pass dual-energy computed tomography.
abstract: OBJECTIVE
  To evaluate noise-optimized monoenergetic postprocessing of dual-energy CT (DE-CT) on image quality in patients with incidental pulmonary embolism in single-pass portal-venous phase CT (CTpv).
  
  
  METHODS
  20 Consecutive patients with incidental pulmonary embolism in contrast-enhanced oncological follow-up DE-CTpvexamination were included in this study. Images were acquired with a 3rd generation DE-CT system in DE mode (100/Sn150 kV) and activated tube current modulation 90 s after contrast agent administration. Subsequently, virtual monoenergetic images (MEI+) were reconstructed at five different keV levels (40, 55, 70, 85, 100) and compared to the standard linearly blended (M_0.8) CTpvimages. Image quality was assessed qualitatively (vascular contrast and detectability of embolism, image noise, iodine influx artifact; two independent readers; 5-point Likert scale; 5 = excellent) and quantitatively by calculating signal-to-noise (SNR) and contrast-to-noise ratios (CNR).
  
  
  RESULTS
  Highest vessel contrast and highest detectability of embolism were observed in MEI+ at 40 keV (4.7 ± 0.4) and 55 keV (4.2 ± 0.6) with significant differences as compared to CTpv(3.6 ± 0.5) and high keV reconstructions (70, 85, 100; p ≤ 0.01). Image noise significantly increased at 40 keV MEI+ compared to all other MEI+ reconstructions and CTpv(p < 0.001). SNR and CNR calculations were highest at 40 keV MEI+ followed by 55 keV and CTpvwith significant differences to high keV MEI+ (85-100).
  
  
  CONCLUSIONS
  Computed MEI+ at low keV levels allow for improved vessel contrast and visualisation of incidental pulmonary embolism in patients with portal-venous phase CT scans by substantially increasing CNR and SNR.
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany. Jakob.Weiss@uni-tuebingen.de.
authors.forename: Jakob
authors.initials: J
authors.lastname: Weiss
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
authors.forename: Mike
authors.initials: M
authors.lastname: Notohamiprodjo
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Bongers
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schabel
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Mangold
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
authors.affiliation: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tübingen, Germany.
authors.forename: Ahmed E
authors.initials: AE
authors.lastname: Othman
mesh_terms: D003287:Contrast Media; D005260:Female; D006801:Humans; D033162:Incidental Findings; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol
keywords: Improved iodine contrast; Incidental pulmonary embolism; Noise-optimized monoenergetic postprocessing; Oncological CT staging