title: Ultrasonography criteria for differentiating ACTH dependency from ACTH independency in 47 dogs with hyperadrenocorticism and equivocal adrenal asymmetry.
abstract: BACKGROUND
  Adrenal ultrasonography (US) in dogs with hyperadrenocorticism (HAC) is commonly used to distinguish adrenocorticotropic hormone (ACTH)-independent (AIHAC) and ACTH-dependent hyperadrenocorticism (ADHAC). To date, no cut-off values for defining adrenal atrophy in cases of adrenal asymmetry have been determined. Given that asymmetrical hyperplasia is sometimes observed in ADHAC, adrenal asymmetry without ultrasonographic proof of adrenocortical tumor such as vascular invasion or metastasis can be equivocal.
  
  
  OBJECTIVE
  The purpose of this study was to compare adrenal US findings between cases of ADHAC and AIHAC in dogs with equivocal adrenal asymmetry (EAA), and to identify useful criteria for their distinction.
  
  
  METHODS
  Forty dogs with EAA were included.
  
  
  METHODS
  Ultrasound reports of HAC dogs with adrenal asymmetry without obvious vascular invasion or metastases were reviewed. Dogs were classified as cases of ADHAC (n = 28) or AIHAC (n = 19), determined by plasma ACTH concentration. The thickness, shape, and echogenicity of both adrenal glands and presence of adjacent vascular compression were compared between AIHAC and ADHAC groups.
  
  
  RESULTS
  The maximal dorsoventral thickness of the smaller gland (SDV) ranged from 2.0 to 5.0 mm in AIHAC and from 5.0 to 15.0 mm in ADHAC. The 95% confidence intervals for estimated sensitivity and specificity of a SDV cut-off set at 5.0 mm in the diagnosis of AIHAC were 82-100 and 82-99%, respectively. Other tested US criteria were found to overlap extensively between the 2 groups, precluding their usefulness for distinction.
  
  
  CONCLUSIONS
  In EAA cases, an SDV ≤5.0 mm is an appropriate cut-off for AIHAC ultrasonographic diagnosis.
authors.affiliation: Internal Medicine Unit, National Veterinary School of Alfort, Maisons-Alfort, France.
authors.forename: G
authors.initials: G
authors.lastname: Benchekroun
authors.forename: P
authors.initials: P
authors.lastname: de Fornel-Thibaud
authors.forename: M I
authors.initials: MI
authors.lastname: Rodríguez Piñeiro
authors.forename: D
authors.initials: D
authors.lastname: Rault
authors.forename: J
authors.initials: J
authors.lastname: Besso
authors.forename: A
authors.initials: A
authors.lastname: Cohen
authors.forename: J
authors.initials: J
authors.lastname: Hernandez
authors.forename: F
authors.initials: F
authors.lastname: Stambouli
authors.forename: E
authors.initials: E
authors.lastname: Gomes
authors.forename: F
authors.initials: F
authors.lastname: Garnier
authors.forename: D
authors.initials: D
authors.lastname: Begon
authors.forename: C
authors.initials: C
authors.lastname: Maurey-Guenec
authors.forename: D
authors.initials: D
authors.lastname: Rosenberg
mesh_terms: D000311:Adrenal Glands / Q000000981:diagnostic imaging / Q000473:pathology*; D000308:Adrenocortical Hyperfunction / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000662:veterinary*; D000324:Adrenocorticotropic Hormone / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D003907:Dexamethasone / Q000494:pharmacology; D004283:Dog Diseases / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000473:pathology; D004285:Dogs; D012189:Retrospective Studies; D014463:Ultrasonography
chemical_list: D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone