title: Usefulness of partial volume effect-corrected F-18 FDG PET/CT for predicting I-131 accumulation in the metastatic lymph nodes of patients with thyroid carcinoma.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the clinical usefulness of partial volume effect (PVE)-corrected F-18 FDG PET/CT for predicting I-131 accumulation in metastatic lymph nodes (mLNs) during I-131 therapy for papillary thyroid carcinoma (PTC).
  
  
  METHODS
  Sixty-five mLNs in 31 PTC patients who underwent F-18 FDG PET/CT in an initial radioiodine therapy (RIT) were retrospectively evaluated. Of these, 25 mLNs were I-131-positive and 40 were I-131-negative. SUVmax and SUVmax with PVE correction (cSUVmax) were measured for each mLN, where PVE correction was performed utilizing a simple table lookup correction method. Then, SUVmax/cSUVmax was compared between I-131-positive and I-131-negative mLNs, including the analyses for the mLNs with small-sized (<1 cm) and weak FDG accumulation (SUVmax <3.5). The predictability for I-131 accumulation with SUVmax/cSUVmax was also compared.
  
  
  RESULTS
  For all 65 mLNs, SUVmax/cSUVmax was significantly higher in I-131-negative than I-131-positive mLNs (p < 0.0001). Only in cSUVmax, I-131-negative mLNs were significantly higher than I-131-positive, in terms of the 30 small-sized mLNs (p = 0.0001) and 14 mLNs with weak FDG uptake (p = 0.007). The highest accuracy in predictability for I-131 accumulation was significantly better with cSUVmax (92 %) than SUVmax (62 %) (p < 0.0001).
  
  
  CONCLUSIONS
  PVE-corrected F-18 FDG PET/CT is a valuable predictor of I-131 accumulation in mLNs during RIT.
authors.affiliation: Departments of Clinical Radiology, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, Fukuoka, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Maruoka
authors.forename: Koichiro
authors.initials: K
authors.lastname: Abe
authors.forename: Shingo
authors.initials: S
authors.lastname: Baba
authors.forename: Takuro
authors.initials: T
authors.lastname: Isoda
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Noriko
authors.initials: N
authors.lastname: Mizoguchi
authors.forename: Go
authors.initials: G
authors.lastname: Akamatsu
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sasaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Honda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D002291:Carcinoma, Papillary; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism / Q000627:therapeutic use; D008207:Lymphatic Metastasis; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D007457:Iodine Radioisotopes; D019788:Fluorodeoxyglucose F18