title: Additional value of integrated PET/CT over PET alone  in the initial staging and follow up of head and neck malignancy.
abstract: OBJECTIVE
  Clinical application of FDG-PET in head and neck cancer includes identification of metastases, unknown primary head and neck malignancy, or second primary carcinoma, and also recurrent tumor after treatment. In this study, the additional value of PET/CT fusion images over PET images alone was evaluated in patients with initial staging and follow up of head and neck malignancy.
  
  
  METHODS
  Forty patients with suspected primary head and neck malignancy and 129 patients with suspected relapse after treatment of head and neck malignancy were included. FDG-PET/CT study was performed after the intravenous administration of FDG (5 MBq/kg). Target of evaluation was set at primary tumor, cervical lymph node, and whole body. PET images and PET with CT fusion images were compared. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Results of PET and PET/CT were compared with postoperative histopathological examination, and case by case comparison of PET and PET/CT results for each region was performed. The additional value of CT images over PET only images was assessed. Statistical differences in sensitivity and specificity were evaluated.
  
  
  RESULTS
  In the comparative evaluation of 507 targets by PET alone and PET/CT, 401 targets showed agreement of the results. Of the 106 discordant targets, 103 showed a positive result on PET alone and negative result on PET/CT. These results showed a significant difference (p< 0.01). Sensitivity of PET/CT was slightly higher than that of PET without statistical significance, while specificity of PET/CT was significantly higher than that of PET alone (Initial staging: 90.5% vs. 62.2%, p < 0.01; Follow up: 97.2% vs. 74.4%, p < 0.01). In Fisher's direct probability test, a significant difference was noted in the sensitivity (Initial staging: 91.3% vs. 87.0%, p < 0.01; Follow up: 93.9% vs. 91.4%, p <0.01).
  
  
  CONCLUSIONS
  Combined PET/CT showed improved diagnostic performance than PET alone by decreasing the number of false positive findings in patients with initial staging and follow up of head and neck malignancy.
authors.affiliation: Department of Stomatology and Maxillofacial Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Ishikita
authors.forename: Noboru
authors.initials: N
authors.lastname: Oriuchi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Higuchi
authors.forename: Go
authors.initials: G
authors.lastname: Miyashita
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Arisaka
authors.forename: Bishnuhari
authors.initials: B
authors.lastname: Paudyal
authors.forename: Pramila
authors.initials: P
authors.lastname: Paudyal
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Hanaoka
authors.forename: Mitsuyuki
authors.initials: M
authors.lastname: Miyakubo
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Nakasone
authors.forename: Akihide
authors.initials: A
authors.lastname: Negishi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yokoo
authors.forename: Keigo
authors.initials: K
authors.lastname: Endo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D006801:Humans; D008297:Male; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed
chemical_list: D019788:Fluorodeoxyglucose F18