title: Use of computed tomography adrenal gland measurement for differentiating ACTH dependence from ACTH independence in 64 dogs with hyperadenocorticism.
abstract: BACKGROUND
  The measurement of adrenal gland size on computed tomography (CT) scan has been proposed for the etiological diagnosis of hyperadrenocorticism (HAC) in dogs. Symmetric adrenal glands are considered to provide evidence for ACTH-dependent hyperadrenocorticism (ADHAC), whereas asymmetry suggests ACTH-independent hyperadrenocorticism (AIHAC). However, there are currently no validated criteria for such differentiation.
  
  
  OBJECTIVE
  The aim of this retrospective study was to compare various adrenal CT scan measurements and the derived ratios in ADHAC and AIHAC cases, and to validate criteria for distinguishing between these conditions in a large cohort of dogs.
  
  
  METHODS
  Sixty-four dogs with HAC (46 ADHAC, 18 AIHAC).
  
  
  METHODS
  Dogs with confirmed HAC and unequivocal characterization of its origin were included. Linear measurements of adrenal glands were made on both cross-sectional and reformatted images.
  
  
  RESULTS
  An overlap was systematically observed between the AIHAC and ADHAC groups for all measurements tested. Overlaps also were observed for ratios tested. For the maximum adrenal diameter ratio derived from reformatted images (rADR), only 1/18 AIHAC dogs had a rADR within the range for ADHAC. For a threshold of 2.08, the 95% confidence intervals for estimated sensitivity and specificity extended from 0.815 to 1.000 and from 0.885 to 0.999, respectively, for AIHAC diagnosis.
  
  
  CONCLUSIONS
  Measurements from cross-sectional or reformatted CT scans are of little use for determining the origin of HAC. However, rADR appears to distinguish accurately between ADHAC and AIHAC, with a rADR > 2.08 highly suggestive of AIHAC.
authors.affiliation: Internal Medicine Unit, National Veterinary School of Alfort, Maisons-Alfort, France.
authors.forename: M I
authors.initials: MI
authors.lastname: Rodríguez Piñeiro
authors.forename: P
authors.initials: P
authors.lastname: de Fornel-Thibaud
authors.forename: G
authors.initials: G
authors.lastname: Benchekroun
authors.forename: F
authors.initials: F
authors.lastname: Garnier
authors.forename: C
authors.initials: C
authors.lastname: Maurey-Guenec
authors.forename: F
authors.initials: F
authors.lastname: Delisle
authors.forename: D
authors.initials: D
authors.lastname: Rosenberg
mesh_terms: D000311:Adrenal Glands / Q000000981:diagnostic imaging* / Q000473:pathology; D000308:Adrenocortical Hyperfunction / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone / Q000097:blood / Q000502:physiology*; D000818:Animals; D003480:Cushing Syndrome / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000662:veterinary; D004283:Dog Diseases / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D004285:Dogs; D005260:Female; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D009929:Organ Size; D010902:Pituitary Gland / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000662:veterinary*
chemical_list: D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone