title: Distinction between benign and malignant adrenal masses: value of T1-weighted chemical-shift MR imaging.
abstract: OBJECTIVE
  Accuracy of T1-weighted chemical-shift MR imaging for the differentiation between benign and malignant adrenal masses was blindly assessed among three radiologists.
  
  
  METHODS
  MR imaging was performed at 1.5 T in 50 patients with 58 adrenal masses, proved benign (n = 38) or malignant (n = 20) based on surgery or growth (malignant) or stable size (benign) for at least 1 year. In-phase spin-echo sequences or in-phase breath-hold fast multiplanar spoiled gradient-recalled echo (FMPSPGR) sequences with a TE of 4.2 msec were compared with opposed-phase breath-hold FMPSPGR sequences with a TR/TE of 35-155/2.2-2.9 and a 90 degrees flip angle for the detection of lipid in adrenal masses. Three radiologists who were blinded to diagnosis and clinical data independently rated the likelihood of a benign adrenal lesion on a five-point scale of confidence.
  
  
  RESULTS
  Mean sensitivity, specificity, and positive predictive value for a definite or probable diagnosis of a benign lesion by the three readers were 87%, 92%, and 95%, respectively. At the highest (definite) confidence of a benign lesion, the mean positive predictive value was 99%, with lower sensitivity (54%). Areas under receiver operating characteristic curves for the three radiologists were .98 (95% confidence interval [CI] = .94-1.00), .96 (CI = .91-1.00), and .95 (CI = .89-1.00). Interobserver variation for the diagnosis of a benign mass was low (kappa = .79).
  
  
  CONCLUSIONS
  Chemical-shift imaging using breath-hold opposed-phase T1-weighted MR images is a reliable and reproducible technique for the diagnosis of most benign adrenal masses at the highest threshold of confidence.
authors.affiliation: Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA.
authors.forename: E K
authors.initials: EK
authors.lastname: Outwater
authors.forename: E S
authors.initials: ES
authors.lastname: Siegelman
authors.forename: P D
authors.initials: PD
authors.lastname: Radecki
authors.forename: C W
authors.initials: CW
authors.lastname: Piccoli
authors.forename: D G
authors.initials: DG
authors.lastname: Mitchell
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D016001:Confidence Intervals; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity