RT Journal Article SR Electronic T1 18F-FDG PET Reduces Unnecessary Hemithyroidectomies for Thyroid Nodules with Inconclusive Cytologic Results JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 770 OP 775 VO 47 IS 5 A1 Lioe-Fee de Geus-Oei A1 Gerlach F.F.M. Pieters A1 Johannes J. Bonenkamp A1 Aart H. Mudde A1 Chantal P. Bleeker-Rovers A1 Frans H.M. Corstens A1 Wim J.G. Oyen YR 2006 UL http://jnm.snmjournals.org/content/47/5/770.abstract AB Fine-needle aspiration biopsy (FNAB) is inconclusive in up to 20% of patients with solitary thyroid nodules. In these cases, hemithyroidectomy is necessary, but only 20% of the nodules prove to be thyroid carcinoma. The aim of this study was to explore the potential of 18F-FDG PET to reduce the number of unnecessary hemithyroidectomies in the preoperative assessment of thyroid nodules with inconclusive FNAB results. Methods: Forty-four consecutive patients, scheduled for hemithyroidectomy because of inconclusive FNAB findings, participated in this prospective study. 18F-FDG PET of the thyroid region was performed before hemithyroidectomy, and standardized uptake values were calculated. The final histopathologic diagnosis served as a standard of reference. Results: Histopathologic examination of the surgical specimens revealed 7 well-differentiated thyroid carcinomas in 6 patients, all accumulating 18F-FDG (negative predictive value, 100%). 18F-FDG accumulated in 13 of 38 benign nodules. The pre-PET probability for cancer in this study population was 14% (6/44), and the post-PET probability increased to 32% (6/19). The percentage of unnecessary hemithyroidectomies in a hypothetical algorithm using 18F-FDG PET was only 30% (13/44), compared with 86% (38/44) without 18F-FDG PET. 18F-FDG PET reduced the number of futile hemithyroidectomies by 66% (25/38) (95% confidence interval, 49%–80%; Fisher's exact test, P = 0.0038). Semiquantitative analysis using standardized uptake values did not help to further reduce this number. Conclusion: In addition to data in the literature demonstrating accurate detection of thyroid cancer by 18F-FDG PET, this study showed that 18F-FDG PET should play an important role in the management of patients with inconclusive cytologic diagnosis of a thyroid nodule. 18F-FDG PET reduced the number of futile hemithyroidectomies by 66%. Although PET is a relatively costly procedure, this cost outweighs the costs and risks associated with unnecessary thyroid surgery.