title: Ultrasonographic assessment of the thyroid gland and adjacent anatomic structures in Indo-Pacific bottlenose dolphins (Tursiops aduncus).
abstract: OBJECTIVE
  To evaluate the use of ultrasonography for thyroid gland assessment in healthy Indo-Pacific bottlenose dolphins (Tursiops aduncus), describe the ultrasonographic appearance of the thyroid gland and adjacent anatomic structures, and identify potential associations between variations in thyroid gland morphology and demographic features in this species.
  
  
  METHODS
  18 captive Indo-Pacific bottlenose dolphins.
  
  
  METHODS
  1,404 ultrasonographic examinations of the thyroid gland and adjacent anatomic structures (eg, cervical lymph nodes, musculature, and vasculature) were performed during the > 3-year study period. Shape, echogenicity, and homogeneity of thyroid glands were assessed, and glands were categorized into morphological configurations on the basis of results of 2-D and 3-D ultrasonographic evaluation. Associations between demographic factors and thyroid gland morphology were assessed.
  
  
  RESULTS
  Thyroid lobes appeared elliptical or fusiform in the transverse scan plane and round to oval in longitudinal scan planes; morphologically, glands comprised 2 lobes joined by an isthmus or a roughly diamond-shaped structure located on the ventral surface of the trachea. Major blood vessels and cervical lymph nodes were identified. Thyroid parenchyma was typically uniform and homogeneous, with echogenic reticulations and well-defined borders. Thyroid glands were hypoechoic or isoechoic relative to the sternocephalicus muscle; echogenicity was greater in adolescents than in adults. Thyroid gland volume differed between sexes, between sexually mature and immature dolphins, and among age groups and was positively correlated with body length and weight.
  
  
  CONCLUSIONS
  Ultrasonography provided a reliable and repeatable method for evaluation of thyroid glands and adjacent anatomic structures in live dolphins.
authors.affiliation: Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China. briankot@yahoo.co.uk
authors.forename: Brian C W
authors.initials: BC
authors.lastname: Kot
authors.forename: Michael T C
authors.initials: MT
authors.lastname: Ying
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Brook
authors.forename: Reimi E
authors.initials: RE
authors.lastname: Kinoshita
authors.forename: Sammy C H
authors.initials: SC
authors.lastname: Cheng
mesh_terms: D000375:Aging; D000818:Animals; D050681:Bottle-Nosed Dolphin / Q000033:anatomy & histology* / Q000254:growth & development; D005260:Female; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging; D009333:Neck / Q000000981:diagnostic imaging; D012737:Sex Factors; D012741:Sexual Maturation; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000254:growth & development; D014463:Ultrasonography