title: Ultrasonography as a method of screening for tracheal invasion by papillary thyroid cancer.
abstract: OBJECTIVE
  To assess the reliability of ultrasonography (US) for detecting tracheal invasion by papillary thyroid cancer (PTC).
  
  
  METHODS
  We reviewed the clinical and surgical data of 509 patients who underwent surgery for primary PTC during 2003, after routine preoperative US.
  
  
  RESULTS
  Ultrasonography showed possible tracheal invasion in 43 of the 509 patients. However, the US findings could not be evaluated in 32 patients because of high tumor calcification, a tumor diameter greater than 4 cm, or tumor extension inferior to the clavicle. We shaved the tracheal wall in 11 patients and resected the tracheal wall in 2 patients. The sensitivity of US for diagnosing of tracheal invasion was 91%, the specificity 93%, the predictive value of a positive test 25%, the predictive value of a negative test 99%, and the accuracy 93%.
  
  
  CONCLUSIONS
  Ultrasonography is a useful method of screening for tracheal invasion. A negative sonogram is a reliable indicator of the absence of tracheal invasion, except when tumors are highly calcified or extend inferior to the clavicle.
authors.affiliation: Kuma Hospital, 8-2-35 Shimoyamate-dori, Chuo-ku, Kobe, 650-0011, Japan.
authors.forename: Chisato
authors.initials: C
authors.lastname: Tomoda
authors.forename: Takashi
authors.initials: T
authors.lastname: Uruno
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Takamura
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ito
authors.forename: Akihiro
authors.initials: A
authors.lastname: Miya
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuzuka
authors.forename: Kanji
authors.initials: K
authors.lastname: Kuma
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
mesh_terms: D000231:Adenocarcinoma, Papillary / Q000000981:diagnostic imaging* / Q000401:mortality / Q000556:secondary* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D011336:Probability; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery*; D013965:Thyroidectomy / Q000379:methods; D014134:Tracheal Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary* / Q000601:surgery; D018608:Ultrasonography, Doppler