title: Assessment of salivary gland dysfunction after radioiodine therapy for thyroid carcinoma using non-contrast-enhanced CT: the significance of changes in volume and attenuation of the glands.
abstract: OBJECTIVE
  Although radiation induced damage to the salivary gland is a known complication of radioactive iodine ((131)I) therapy for thyroid carcinoma, prediction of the severity and reversibility of sialoadenitis is difficult. Our aim was to correlate the extent of salivary dysfunction assessed by salivary gland scintigraphy with changes in the volume and attenuation of salivary glands on nonenhanced CT in postoperative patients with thyroid cancer treated with RIT.
  
  
  METHODS
  Forty patients with thyroid carcinoma, 13 men (age range, 21-80 years) and 27 women (age range, 28-75 years) who underwent a total thyroidectomy and were treated with RIT were assessed retrospectively. On CT, the percentage of volume reduction and the difference in attenuation of the parotid and submandibular glands after RIT were determined and correlated with the extent of radiation-induced salivary dysfunction on scintigraphy.
  
  
  RESULTS
  The salivary gland volume significantly decreased with an increase in the dysfunction grade on scintigraphy for both the parotid and submandibular glands (P < .001). The attenuation significantly increased with an increase in the dysfunction grade on scintigraphy for the parotid gland (P < .001), but not for the submandibular gland. The cutoff value of volume reduction to diagnose severe gland dysfunction was 19.5% (sensitivity, 86.0%; specificity, 100%) for the parotid gland and 31.0% (sensitivity, 100%; specificity, 97.0%) for the submandibular gland, and that of the attenuation change was 9.8 HU (sensitivity, 81.0%; specificity, 95%) for the parotid gland.
  
  
  CONCLUSIONS
  The reduction in volume of the parotid and submandibular glands and the increase in attenuation of the parotid gland on nonenhanced CT can be indicators of the grade of RIT-induced salivary dysfunction.
authors.affiliation: Department of Radiology, Asahikawa Medical University, Asahikawa, Japan.
authors.forename: B
authors.initials: B
authors.lastname: Nabaa
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: A
authors.initials: A
authors.lastname: Okizaki
authors.forename: T
authors.initials: T
authors.lastname: Aburano
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use*; D008875:Middle Aged; D009929:Organ Size; D011832:Radiation Injuries / Q000000981:diagnostic imaging* / Q000209:etiology*; D019275:Radiopharmaceuticals / Q000009:adverse effects / Q000627:therapeutic use; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012466:Salivary Gland Diseases / Q000000981:diagnostic imaging* / Q000209:etiology*; D012469:Salivary Glands / Q000528:radiation effects; D012680:Sensitivity and Specificity; D012796:Sialography / Q000379:methods; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals