title: Prognostic Impact of Ultrasonography Features and (18)F-Fluorodeoxyglucose Uptake in Patients With Papillary Thyroid Microcarcinoma.
abstract: OBJECTIVE
  To evaluate the prognostic impact of ultrasonography (US) features and (18)F-fluorodeoxyglucose ((18)F-FDG) uptake in patients with papillary thyroid microcarcinoma (PTMC).
  
  
  METHODS
  This study included 74 patients with a single PTMC diagnosed pathologically. Patients underwent total thyroidectomy, or near-total thyroidectomy and staging thyroid US and positron emission tomography (PET) were performed prior to surgery. US features of thyroid nodules were reviewed retrospectively and the maximum standard uptake value (SUV) of nodules was semiquantitatively analyzed on (18)F-FDG PET/computed tomography (CT). Patients were followed-up for recurrence, which was defined as PTC on cytology results, elevated serum thyroglobulin (Tg) or anti-Tg antibody levels, or uptake on whole-body scintigraphy. We used univariate and multivariate analyses to evaluate whether poor prognostic outcomes were associated with US features or SUV values derived from PET/CT of nodules. In addition, subjects were divided into 2 groups for subgroup analyses: one with nodules equal to or larger than 5 mm and one with nodules smaller than 5 mm.
  
  
  RESULTS
  Among the 74 patients, there was no recurrence. Thus we evaluated the correlation between SUV value and US features with poor prognostic factors of PTMC which included extrathyroid extension, central and lateral lymph node (LN) metastasis. However no clinicopathologic factors were associated with extrathyroid extension, central LN metastasis, or lateral LN metastasis.
  
  
  CONCLUSIONS
  In patients with PTMC, US features and SUV values on FDG-PET were not related to extrathyroid extension or LN metastasis. However, future studies with a larger sample size and longer follow-up should be performed to verify the results of this study.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Ji Won
authors.initials: JW
authors.lastname: Seo
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Hwang
authors.affiliation: Division of Nuclear Medicine, Department of Radiology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Arthur
authors.initials: A
authors.lastname: Cho
authors.affiliation: Department of Research Affairs, Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Moon
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kwak
keywords: Papillary Thyroid Microcarcinoma; Positron Emission Tomography; Thyroid; Ultrasonography