title: Dual-energy computed tomography (DECT) in renal masses: nonlinear versus linear blending.
abstract: OBJECTIVE
  To investigate whether a nonlinear-blending algorithm improves tumor conspicuity and image quality in the evaluation of renal masses at dual-energy computed tomography (DECT) during nephrographic phase of enhancement.
  
  
  METHODS
  The Institutional Review Board approved this retrospective study from archival material from patients consenting to the use of medical records for research purposes. A retrospective review of contrast-enhanced abdominal DECT scans in 45 patients (mean age, 59.5 years; range, 24-84 years) was performed. DECT data were reconstructed using nonlinear and linear blending. A region of interest was located within tumors and adjacent normal parenchyma; attenuation differences and contrast-to-noise ratios (CNRs) were calculated for renal masses on nonlinear- and linear-blended images. The two datasets were subjectively compared in terms of tumor detection and image quality. An exact Wilcoxon's matched pairs signed rank and marginal homogeneity tests were used to test whether differences in attenuation, CNR, and subjective assessment were greater using nonlinear blending.
  
  
  RESULTS
  The mean difference in attenuation for renal masses and adjacent portion of renal parenchyma was 138.4 Hounsfield units ± 28.9 SD using nonlinear blending, and 121.6 HU ± 18.0 SD using linear blending (P < .001). Mean CNR was 12.6 ± 2.5 SD using nonlinear blending, and 9.6 ± 2.2 SD using 0.3 linear-blended (P < .001). No significant difference in tumor detection was observed between the two algorithms. Image quality was significantly better (P < .001) using nonlinear blending.
  
  
  CONCLUSIONS
  Compared with standard linear blending, nonlinear-blending algorithm improves tumor conspicuity and image quality in renal masses at DECT evaluation during nephrographic phase of enhancement.
authors: Department of Radiological Sciences, Policlinico G. Martino, Via Consolare Valeria 1, 98125 Messina, Italy.
authors: Giorgio
authors: G
authors: Ascenti
authors: Bernhard
authors: B
authors: Krauss
authors: Silvio
authors: S
authors: Mazziotti
authors: Achille
authors: A
authors: Mileto
authors: Nicola
authors: N
authors: Settineri
authors: Sergio
authors: S
authors: Vinci
authors: Rocco
authors: R
authors: Donato
authors: Michele
authors: M
authors: Gaeta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003198:Computer Simulation; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult