title: CT and MR distinction of adenomas and nonadenomas of the adrenal gland.
abstract: OBJECTIVE
  Because the distinction between adenomas and nonadenomas of the adrenal gland is essential, we investigated which of the following parameters--size, CT attenuation values, MRI signal intensity ratios on T1- and T2-weighted sequences, calculated T2 relaxation times, or T2 relaxation time ratios--provides better discrimination.
  
  
  METHODS
  We compared these parameters in 44 adrenal masses of 37 patients by means of the Student t test and receiver operating characteristics (ROC) analyses.
  
  
  RESULTS
  Only size, CT attenuation values, and signal intensity ratios on T2-weighted MR images of adenomas showed a significant difference from those of nonadenomas. With use of ROC analysis, CT demonstrated a significantly larger area under the curve compared to size and T2 signal intensity ratios, indicating superior performance.
  
  
  CONCLUSIONS
  We found attenuation values on non-contrast-enhanced CT to be the best method in discriminating adrenal adenomas from nonadenomas. Adrenal masses with CT attenuation values below 15 HU warrant no further investigations.
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, Leiden University Hospital, The Netherlands.
authors.forename: A R
authors.initials: AR
authors.lastname: van Erkel
authors.forename: A P
authors.initials: AP
authors.lastname: van Gils
authors.forename: M
authors.initials: M
authors.lastname: Lequin
authors.forename: C
authors.initials: C
authors.lastname: Kruitwagen
authors.forename: J L
authors.initials: JL
authors.lastname: Bloem
authors.forename: T H
authors.initials: TH
authors.lastname: Falke
mesh_terms: D000236:Adenoma / Q000175:diagnosis* / Q000000981:diagnostic imaging; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D000311:Adrenal Glands / Q000000981:diagnostic imaging / Q000473:pathology; D018246:Adrenocortical Adenoma / Q000175:diagnosis / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D014057:Tomography, X-Ray Computed