title: Spinal dual-energy computed tomography: improved visualisation of spinal tumorous growth with a noise-optimised advanced monoenergetic post-processing algorithm.
abstract: BACKGROUND
  The aim of this study was to evaluate the effect of advanced monoenergetic post-processing (MEI+) on the visualisation of spinal growth in contrast-enhanced dual-energy CT (DE-CT).
  
  
  METHODS
  Twenty-six oncologic patients (age, 61 ± 17 years) with spinal tumorous growth were included. Patients underwent contrast-enhanced dual-energy CT on a third-generation dual-source CT scanner. Image acquisition was in dual-energy mode (100/Sn150kV), and scans were initiated 90 s after contrast agent administration. Virtual monoenergertic images (MEI+) were reconstructed at four different kiloelectron volts (keV) levels (40, 60, 80, 100) and compared to the standard blended portal venous computed tomography (CTpv). Image quality was assessed qualitatively (conspicuity, delineation, sharpness, noise, confidence; two independent readers; 5-point Likert scale; 5 = excellent) and quantitatively by calculating signal-to-noise (SNR) and contrast-to-noise-ratios (CNR). For a subgroup of 10 patients with MR imaging within 4 months of the DE-CT, we compared the monoenergetic images to the MRIs qualitatively.
  
  
  RESULTS
  Highest contrast of spinal growth was observed in MEI+ at 40 keV, with significant differences to CTpvand all other keV reconstructions (60, 80, 100; p < 0.01). Highest conspicuity, delineation and sharpness were observed in MEI+ at 40 keV, with significant differences to CTpv(p < 0.001). Similarly, MEI+ at 40 keV yielded highest diagnostic confidence (4.6 ± 0.6), also with significant differences to CTpv(3.45 ± 0.9, p < 0.001) and to high keV reconstructions (80, 100; p ≤ 0.001). Similarly, CNR calculations revealed highest scores for MEI+ at 40 keV followed by 60 keV and CTpv, with significant differences to high keV MEI+ reconstructions. Qualitative analysis scores peaked for MR images followed by the MEI+ 40-keV reconstructions.
  
  
  CONCLUSIONS
  MEI+ at low keV levels can significantly improve image quality and delineation of spinal growth in patients with portal-venous phase CT scans due to increased CNR and limited image noise.
authors: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.
authors: Mareen
authors: M
authors: Kraus
authors: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.
authors: Jakob
authors: J
authors: Weiss
authors: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.
authors: Nadja
authors: N
authors: Selo
authors: Siemens Healthcare GmbH, Erlangen, Germany.
authors: Thomas
authors: T
authors: Flohr
authors: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.
authors: Mike
authors: M
authors: Notohamiprodjo
authors: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.
authors: Fabian
authors: F
authors: Bamberg
authors: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany.
authors: Konstantin
authors: K
authors: Nikolaou
authors: Department of Diagnostic and Interventional Radiology, Eberhard Karls University Tuebingen, Hoppe-Seyler-Straße 3, 72076, Tuebingen, Germany. Ahmed.e.Othman@googlemail.com.
authors: Ahmed E
authors: AE
authors: Othman
mesh_terms: D000465:Algorithms; D016477:Artifacts; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011856:Radiographic Image Enhancement / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D059629:Signal-To-Noise Ratio; D013120:Spinal Cord Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
keywords: Dual-energy CT; Monoenergetic post-processing; Spinal tumour