title: Dual-energy CT: clinical application in differentiating an adrenal adenoma from a metastasis.
abstract: BACKGROUND
  Application of dual-energy CT in characterization of adrenal nodules has not been well evaluated.
  
  
  OBJECTIVE
  To evaluate the ability of dual-energy CT scan to differentiate an adrenal adenoma from a metastasis.
  
  
  METHODS
  Fifty-five patients presenting 63 adrenal nodules underwent dual-energy CT scan at tube voltages of 80 kVp and 140 kVp. Mean attenuation values were measured for every nodule at 80/140 kVp and at 40/100 keV. Mean attenuation value changes between 140 kVp and 80 kVp (MAVC140-80kVp) and mean attenuation value changes between 100 keV and 40 keV (MAVC100-40keV) were calculated.
  
  
  RESULTS
  Of the 63 adrenal nodules available for analyses, 42 nodules were classified as adenoma (26 lipid-rich and 16 lipid-poor) and 21 were classified as metastases. MAVC140-80kVp and MAVC100-40keV of all adenomas (including lipid-poor and lipid-rich) were significantly higher than metastases (P < 0.001). According to receiver-operating characteristic (ROC) curve analyses, areas under the ROC curve of MAVC140-80kVp and MAVC100-40keV for diagnosing adrenal adenomas were both of 0.964. When the cut-off points were set at 2.42 HU and 6.95 HU for MAVC140-80kVp and MAVC100-40keV, the two parameters both had a sensitivity of 78.6% and a specificity of 100% in adenoma diagnosis.
  
  
  CONCLUSIONS
  Unique energy spectrum information provided by dual-energy CT scan displays a high capacity to distinguish adrenal adenoma from metastasis.
authors: Department of Medical Imaging, The First People's Hospital of Wujiang, Wujiang, PR China.
authors: Jiang Wei
authors: JW
authors: Shi
authors: Hong Zhi
authors: HZ
authors: Dai
authors: Li
authors: L
authors: Shen
authors: Dong Feng
authors: DF
authors: Xu
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000310:Adrenal Gland Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: X-ray computed tomography; adrenal gland neoplasm; differential diagnosis