title: Characterization of follicular thyroid nodules at fine needle aspiration biopsy using double phase thallium-201 imaging: comparison of visual and semiquantitative analyses.
abstract: OBJECTIVE
  To compare visual and semiquantitative indices of double phase thallium-201 thyroid scintigraphy (DTS) for differentiation of malignant nodules by indeterminate fine needle aspiration biopsy (FNAB) results.
  
  
  METHODS
  DTS (early; 15 minutes; delayed, 2 hour) were performed after injection of 37MBq of thallium-201 in 60 patients with indeterminate FNAB.
  
  
  RESULTS
  With grade 4 and 5, sensitivity and specificity were 51.4% and 78.3%, respectively. With early lesion to nonlesion ratio (L/N) 1.49, sensitivity and specificity were 97.3% and 39.1%, respectively. With delayed L/N 1.89, sensitivity and specificity were 70.3% and 78.3%, respectively. With wash-out rate (WR) 18.93%, sensitivity and specificity were 89.2% and 82.6%. Early L/N was superior to delayed L/N and WR for the detection of malignant thyroid nodules.
  
  
  CONCLUSIONS
  Visual assessment had a limited value for differentiation of follicular nodules. The optimal semiquantitative indices were 1.49 for early L/N and 1.89 for delayed L/N. Also, optimal WR was 18.93%. The early L/N was superior to delayed L/N and WR for the detection of malignant thyroid nodular lesions. However, visual assessment and early L/N of DTS showed similar results. Visual analysis and semiquantitative indices of DTS could not differentiate follicular carcinoma and follicular variant of papillary thyroid cancer.
authors.affiliation: Department of Nuclear Medicine, Pusan National University Hospital, Busan, Republic of Korea.
authors.forename: Seong-Jang
authors.initials: SJ
authors.lastname: Kim
authors.forename: In-Ju
authors.initials: IJ
authors.lastname: Kim
authors.forename: Yang-Ho
authors.initials: YH
authors.lastname: Kang
authors.forename: Yong-Ki
authors.initials: YK
authors.lastname: Kim
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging; D018265:Carcinoma, Papillary, Follicular / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D013794:Thallium Radioisotopes; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging*; D016606:Thyroid Nodule / Q000000981:diagnostic imaging*
chemical_list: D013794:Thallium Radioisotopes