title: Sonographic evaluation of the thyroid size in neonates.
abstract: OBJECTIVE
  To validate the use of the ratio between the total transverse diameters of the thyroid lobes (Th) and the width of the trachea (Tr)-the Th:Tr or Yasumoto ratio-as a sonographic method for estimating thyroid size, and to determine reference values for this ratio and for thyroid volume in neonates.
  
  
  METHODS
  In this cross-sectional study, we evaluated thyroid size according to the Yasumoto ratio and the thyroid volume calculated with the ellipsoid formula in 125 healthy, euthyroid, iodine-sufficient, full-term neonates.
  
  
  RESULTS
  The mean thyroid gland volume was 1.00 ml (95% confidence interval, 0.95-1.03 ml), and the mean Yasumoto ratio was 2.29 (95% confidence interval, 2.21-2.31). The lower- and upper-limit results falling within 2 SDs of the mean were 0.45 ml and 1.53 ml for the volume and 1.71 and 2.87 for the ratio.
  
  
  CONCLUSIONS
  In full-term, euthyroid, iodine-sufficient neonates, the normal reference interval for thyroid volume measured on sonography was 0.45-1.53 ml and that for the Yasumoto ratio was 1.71-2.87. A ratio of 1.7 may be applied as the cutoff value for sonographic diagnosis of thyroid dysgenesis in full-term neonates with congenital hypothyroidism. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 43:224-229, 2015.
authors.affiliation: Santa Casa de São Paulo Medical School, São Paulo; Brazil and Radiology Service, Cassiano Antonio Moraes Teaching Hospital of the Federal University of Espirito Santo (HUCAM-UFES), Vitória-ES, Brazil.
authors.forename: Ronald
authors.initials: R
authors.lastname: Freire
authors.affiliation: Endocrinology and Metabolism Discipline in Santa Casa de São Paulo Medical School, São Paulo-Brazil, Brazil.
authors.forename: Osmar
authors.initials: O
authors.lastname: Monte
authors.affiliation: Santa Casa de São Paulo Medical School, São Paulo, Brazil.
authors.forename: Eduardo Kiyoshi
authors.initials: EK
authors.lastname: Tomimori
authors.affiliation: Clinical Analysis Section, Pathology Division, Adolfo Lutz Institute, São Paulo, Brazil.
authors.forename: Regina Maria
authors.initials: RM
authors.lastname: Catarino
authors.affiliation: HUCAM-UFES, Vitória-ES, Brazil.
authors.forename: Thais
authors.initials: T
authors.lastname: Sterza
authors.affiliation: Neonatal Unit, HUCAM-UFES, Vitória-ES, Brazil.
authors.forename: Thatyana
authors.initials: T
authors.lastname: Rocha
authors.affiliation: Neonatal Unit, HUCAM-UFES, Vitória-ES, Brazil.
authors.forename: Katia Cristine Carvalho
authors.initials: KCC
authors.lastname: Pereira
authors.affiliation: São Marcos Laboratory, Vila Velha-ES, Brazil.
authors.forename: Hortensio Simões
authors.initials: HS
authors.lastname: Mattos
authors.affiliation: São Marcos Laboratory, Vila Velha-ES, Brazil.
authors.forename: Leonardo Barros
authors.initials: LB
authors.lastname: Fagundes
authors.affiliation: São Marcos Laboratory, Vila Velha-ES, Brazil.
authors.forename: Marcelo Martins
authors.initials: MM
authors.lastname: Liberato
authors.affiliation: São Marcos Laboratory, Vila Velha-ES, Brazil.
authors.forename: Luiz Wagner Rodrigues
authors.initials: LWR
authors.lastname: Dos Santos
authors.affiliation: Neonatal Triage Unit, Reference Service of Espírito Santo, APAE, Vitória-ES, Brazil.
authors.forename: Adeberto
authors.initials: A
authors.lastname: Pereira
authors.affiliation: Neonatal Triage Unit, Reference Service of Espírito Santo, APAE, Vitória-ES, Brazil.
authors.forename: Terezinha
authors.initials: T
authors.lastname: Cintra
authors.affiliation: Neonatal Triage Unit, Reference Service of Espírito Santo, APAE, Vitória-ES, Brazil.
authors.forename: Christina
authors.initials: C
authors.lastname: Hegner
authors.affiliation: Neonatal Triage Unit, Reference Service of Espírito Santo, APAE, Vitória-ES, Brazil.
authors.forename: Daniela
authors.initials: D
authors.lastname: Lube
authors.affiliation: Department of Internal Medicine, Vila Velha School of Medicine, University of Vila, Velha-ES, Brazil.
authors.forename: Mylene
authors.initials: M
authors.lastname: Murad
keywords: congenital hypothyroidism; neonate; normal anatomy; thyroid; ultrasonography