title: Combined (99m)Tc-methoxyisobutylisonitrile scintigraphy and fine-needle aspiration cytology offers an accurate and potentially cost-effective investigative strategy for the assessment of solitary or dominant thyroid nodules.
abstract: OBJECTIVE
  Fine-needle aspiration (FNA) has revolutionised the care of patients with thyroid nodules and is the initial investigation of choice. However, as a result of nondiagnostic (Thy1) and nonneoplastic (Thy2) specimens, it remains an imperfect sole solution with a range of sensitivities and a high inadequate ratio. Therefore the British Thyroid Association (BTA) guidelines recommend a second FNA immediately for Thy1 specimens and 3-6 months later for Thy2 specimens. Patients must be followed up to exclude malignancy. In this study we assessed the performance of MIBI scintigraphy for diagnosing thyroid malignancy and the cost-effectiveness of a combined FNA/MIBI investigative strategy for the management of thyroid nodules.
  
  
  METHODS
  The diagnostic performance of MIBI scintigraphy was calculated from a retrospective review of local data combined with a meta-analysis of the published literature. Decision tree analysis was used to calculate the cost-effectiveness of a combined FNA/MIBI investigative strategy compared to the BTA guidelines.
  
  
  RESULTS
  From 712 patients, the sensitivity, specificity, PPV and NPV of MIBI scintigraphy for the diagnosis of malignancy were 96 %, 46 %, 34 % and 97 %, respectively. MIBI-based strategies were more accurate and associated with lower cost per patient (£1,855/<euro>2,125 vs. £2,445/<euro>2,801) and lower cost per cancer diagnosed (£1,902/<euro>2,179 vs. £2,469/<euro>2,828) with negligible change in life expectancy.
  
  
  CONCLUSIONS
  Due to its high NPV, MIBI scintigraphy can usefully exclude malignancy for Thy1 and Thy2 lesions. Its low specificity means MIBI scintigraphy cannot be recommended as a first-line investigation, but as a second-line investigation MIBI scintigraphy may lead to a lower rate of unnecessary thyroidectomies. Combined FNA/MIBI strategies are potentially cost-effective in the management of solitary or dominant thyroid nodules.
authors.affiliation: Department of Nuclear Medicine, Brighton and Sussex University Hospitals NHS Trust, Brighton, UK, anita.wale@doctors.org.uk.
authors.forename: Anita
authors.initials: A
authors.lastname: Wale
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Miles
authors.forename: Barnaby
authors.initials: B
authors.lastname: Young
authors.forename: Charles
authors.initials: C
authors.lastname: Zammit
authors.forename: Anthony
authors.initials: A
authors.lastname: Williams
authors.forename: John
authors.initials: J
authors.lastname: Quin
authors.forename: Sabina
authors.initials: S
authors.lastname: Dizdarevic
mesh_terms: D000328:Adult; D044963:Biopsy, Fine-Needle / Q000191:economics*; D003362:Cost-Benefit Analysis; D006801:Humans; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D017256:Technetium Tc 99m Sestamibi; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology*
chemical_list: D017256:Technetium Tc 99m Sestamibi
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