title: Imaging characteristics of hyperfunctioning parathyroid adenomas using multiphase multidectector computed tomography: a quantitative and qualitative approach.
abstract: OBJECTIVE
  The objective of the study was to characterize the enhancement pattern of hyperfunctioning parathyroid adenomas on multiphase multidetector computed tomography (CT) or 4-dimensional CT.
  
  
  METHODS
  We retrospectively studied the enhancement patterns of 48 pathologically confirmed parathyroid adenomas with 4-dimensional CT, compliant with institutional review and the Health Insurance Portability and Accountability Act. Region-of-interest analysis was done at baseline and at arterial (25 seconds), venous (55 seconds), and delayed (85 seconds) enhancement phases over the adenoma and adjacent normal thyroid tissue. Qualitative and quantitative analysis was done. Discriminant functions were calculated using a multivariate logistic regression model, and receiver operating characteristic curves were measured.
  
  
  RESULTS
  Adenomas are lower than thyroid in density, demonstrate avid early contrast enhancement, and show rapid wash-out of contrast. Adenomas and thyroid had baseline Hounsfield unit attenuations of 35 ± 11 and 94 ± 21 and enhancement percentage change from baseline to arterial of 493% ± 328% and 132% ± 148%, respectively (P < 0.0001 both). Quantitative analysis showed that these 2 measures of baseline density and the percentage change from baseline to arterial were the most powerful discriminatory features, with contrast wash-out from arterial peak to venous phase being a less powerful discriminator. Several discriminant functions were derived, the best of which was: X = 13.74 - (0.207 × baseline Hounsfield unit) - (0.006 × percent density change from baseline to arterial). X > 0.2 classifies tissue as parathyroid with high certainty (area under the receiver operating characteristic curve = 0.98; specificity, 0.938; sensitivity, 0.999).
  
  
  CONCLUSIONS
  Parathyroid adenomas have a characteristic enhancement pattern that can be distinguished from thyroid tissue: the key diagnostic discriminators are baseline density, percentage change in density from baseline to arterial enhancement, and percentage decrease in density from arterial to venous phases.
authors.affiliation: Department of Radiology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA.
authors.forename: Thinh H
authors.initials: TH
authors.lastname: Vu
authors.forename: Nandita
authors.initials: N
authors.lastname: Guha-Thakurta
authors.forename: Robyn K
authors.initials: RK
authors.lastname: Harrell
authors.forename: Salmaan
authors.initials: S
authors.lastname: Ahmed
authors.forename: Ashok J
authors.initials: AJ
authors.lastname: Kumar
authors.forename: Valen E
authors.initials: VE
authors.lastname: Johnson
authors.forename: Nancy D
authors.initials: ND
authors.lastname: Perrier
authors.forename: Leena M
authors.initials: LM
authors.lastname: Hamberg
authors.forename: George J
authors.initials: GJ
authors.lastname: Hunter
authors.forename: Dawid
authors.initials: D
authors.lastname: Schellingerhout
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging*; D012372:ROC Curve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C054871:ioversol