Background: Thyroid nodular disease is a very common clinical problem. The diagnostic algorithm includes laboratory tests, thyroid ultrasound (US), thyroid scintigraphy, and, if necessary, US-guided fine-needle aspiration cytology. However, cytology results are reported as indeterminate in a not negligible number of patients. This is a central problem in the workup of patients, since about 55-85% of those undergoing surgery do not have thyroid cancer at final histology diagnosis. The aim of this study was to evaluate prospectively the role of Tc-99m-methoxy-isobutyl-isonitrile (Tc-99m-MIBI) thyroid scintigraphy in differentiating malignant from benign thyroid nodules with indeterminate cytology using quantitative analysis. Method: One hundred five patients affected by nodular thyroid goiter and with a euthyroid or hypothyroid functional status were prospectively evaluated. All patients had a suspicious nodule >= 15 mm in maximal diameter on US. All nodules were "cold'' on Tc-99m-pertechnetate scintigraphy and had a cytological diagnosis of class III or IV according to the Bethesda system. Planar images of the thyroid were acquired 10 and 60 minutes after Tc-99m-MIBI administration. All cold nodules were MIBI-positive. Using quantitative analysis, the MIBI washout index (WOind) was calculated as a percentage reduction value of mean MIBI nodular uptake between early (+10 minutes) and late (+60 minutes) scans. Results: Subdividing the patients into positive and negative for malignancy (either including or excluding patients with Hurthle cell adenoma) and performing receiver operating characterist curve analysis, the optimal WOind cutoff in differentiating malignant from benign follicular lesions was set at -19%. The overall sensitivity and specificity of Tc-99m-MIBI quantitative analysis in identifying patients with malignant lesions was 100% and 90.9%, respectively. However, after excluding patients with Hurthle cell adenomas from the negative patient group, the overall sensitivity and specificity both reached 100%. Conclusion: The use of MIBI scintigraphy using quantitative analysis in the workup of cold nodules with indeterminate cytology is suggested in order to stratify patient risk for a malignant lesion better, thus reducing the number of patients referred to surgery. Surgical treatment should be planned in those patients with a WOind up to -19%.

99mTc-Methoxy-Isobutyl-Isonitrile Scintigraphy Is a Useful Tool for Assessing the Risk of Malignancy in Thyroid Nodules with Indeterminate Fine-Needle Cytology

CAMPENNI', Alfredo
Primo
;
SIRACUSA, MASSIMILIANO;ALIBRANDI, Angela;PIGNATA, SALVATORE ANTONIO;GIOVINAZZO, SALVATORE;TRIMARCHI, Francesco;RUGGERI, Rosaria Maddalena;BALDARI, Sergio
Ultimo
2016

Abstract

Background: Thyroid nodular disease is a very common clinical problem. The diagnostic algorithm includes laboratory tests, thyroid ultrasound (US), thyroid scintigraphy, and, if necessary, US-guided fine-needle aspiration cytology. However, cytology results are reported as indeterminate in a not negligible number of patients. This is a central problem in the workup of patients, since about 55-85% of those undergoing surgery do not have thyroid cancer at final histology diagnosis. The aim of this study was to evaluate prospectively the role of Tc-99m-methoxy-isobutyl-isonitrile (Tc-99m-MIBI) thyroid scintigraphy in differentiating malignant from benign thyroid nodules with indeterminate cytology using quantitative analysis. Method: One hundred five patients affected by nodular thyroid goiter and with a euthyroid or hypothyroid functional status were prospectively evaluated. All patients had a suspicious nodule >= 15 mm in maximal diameter on US. All nodules were "cold'' on Tc-99m-pertechnetate scintigraphy and had a cytological diagnosis of class III or IV according to the Bethesda system. Planar images of the thyroid were acquired 10 and 60 minutes after Tc-99m-MIBI administration. All cold nodules were MIBI-positive. Using quantitative analysis, the MIBI washout index (WOind) was calculated as a percentage reduction value of mean MIBI nodular uptake between early (+10 minutes) and late (+60 minutes) scans. Results: Subdividing the patients into positive and negative for malignancy (either including or excluding patients with Hurthle cell adenoma) and performing receiver operating characterist curve analysis, the optimal WOind cutoff in differentiating malignant from benign follicular lesions was set at -19%. The overall sensitivity and specificity of Tc-99m-MIBI quantitative analysis in identifying patients with malignant lesions was 100% and 90.9%, respectively. However, after excluding patients with Hurthle cell adenomas from the negative patient group, the overall sensitivity and specificity both reached 100%. Conclusion: The use of MIBI scintigraphy using quantitative analysis in the workup of cold nodules with indeterminate cytology is suggested in order to stratify patient risk for a malignant lesion better, thus reducing the number of patients referred to surgery. Surgical treatment should be planned in those patients with a WOind up to -19%.
File in questo prodotto:
File Dimensione Formato  
CAMPENNI' Thyroid 2016.pdf

solo utenti autorizzati

Descrizione: E-pub
Tipologia: Versione Editoriale (PDF)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 260.63 kB
Formato Adobe PDF
260.63 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Thyroid_2016 (1).pdf

solo utenti autorizzati

Descrizione: Articolo principale a stampa
Tipologia: Versione Editoriale (PDF)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 3.99 MB
Formato Adobe PDF
3.99 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/3092719
Citazioni
  • ???jsp.display-item.citation.pmc??? 8
  • Scopus 28
  • ???jsp.display-item.citation.isi??? 25
social impact