title: Can single-phase dual-energy CT reliably identify adrenal adenomas?
abstract: OBJECTIVE
  To evaluate whether single-phase dual-energy-CT-based attenuation measurements can reliably differentiate lipid-rich adrenal adenomas from malignant adrenal lesions.
  
  
  METHODS
  We retrospectively identified 51 patients with adrenal masses who had undergone contrast-enhanced dual-energy-CT (140/100 or 140/80 kVp). Virtual non-contrast and colour-coded iodine images were generated, allowing for measurement of pre- and post-contrast density on a single-phase acquisition. Adrenal adenoma was diagnosed if density on virtual non-contrast images was ≤10 HU. Clinical follow-up, true non-contrast CT, PET/CT, in- and opposed-phase MRI, and histopathology served as the standard of reference.
  
  
  RESULTS
  Based on the standard of reference, 46/57 (80.7%) adrenal masses were characterised as adenomas or other benign lesions; 9 malignant lesions were detected. Based on a cutoff value of 10 HU, virtual non-contrast images allowed for correct identification of adrenal adenomas in 33 of 46 (71%), whereas 13/46 (28%) adrenal adenomas were lipid poor with a density ≥10 HU. Based on the threshold of 10 HU on the virtual non-contrast images, the sensitivity, specificity, and accuracy for detection of benign adrenal lesions was 73%, 100%, and 81% respectively.
  
  
  CONCLUSIONS
  Virtual non-contrast images derived from dual-energy-CT allow for accurate characterisation of lipid-rich adrenal adenomas and can help to avoid additional follow-up imaging.
  
  
  CONCLUSIONS
  • Adrenal adenomas are a common lesion of the adrenal glands. • Differentiation of benign adrenal adenomas from malignant adrenal lesions is important. • Dual-energy based virtual non-contrast images help to evaluate patients with adrenal adenomas.
authors.affiliation: Institute for Clinical Radiology, University of Munich, Grosshadern Campus, Marchioninistr. 15, 81377, Munich, Germany, andreas.helck@med.uni-muenchen.de.
authors.forename: A
authors.initials: A
authors.lastname: Helck
authors.forename: N
authors.initials: N
authors.lastname: Hummel
authors.forename: F G
authors.initials: FG
authors.lastname: Meinel
authors.forename: T
authors.initials: T
authors.lastname: Johnson
authors.forename: K
authors.initials: K
authors.lastname: Nikolaou
authors.forename: A
authors.initials: A
authors.lastname: Graser
mesh_terms: D000306:Adrenal Cortex Neoplasms / Q000000981:diagnostic imaging*; D018246:Adrenocortical Adenoma / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult