title: A Prospective Comparative Study of Parathyroid Dual-Phase Scintigraphy, Dual-Isotope Subtraction Scintigraphy, 4D-CT, and Ultrasonography in Primary Hyperparathyroidism.
abstract: OBJECTIVE
  Preoperative localization of the diseased parathyroid gland(s) in primary hyperparathyroidism allows for minimally invasive surgery. This study was designed to establish the optimal first-line preoperative imaging modality.
  
  
  METHODS
  Ninety-one patients were studied consecutively in a prospective head-to-head comparison of dual isotope (Tc-MIBI vs I) subtraction parathyroid scintigraphy (PS), dual-phase PS, 4-dimensional (4D) CT, and ultrasonography (US). Surgery, histological confirmation, and postoperative normalization of Ca and parathyroid hormone were the reference standard.
  
  
  RESULTS
  Ninety-seven hyperfunctioning parathyroid glands (HPGs) were identified by the reference standard. Sensitivity and specificity for subtraction PS, dual-phase PS, 4D-CT, and US were 93%, 65%, 58%, and 57% as well as 99%, 99.6%, 86%, and 95%, respectively. Interrater agreement was excellent for subtraction PS (κ = 0.96) while only fair for 4D-CT (κ = 0.34). Pinhole imaging and subtraction of delayed images (the latter especially in case of a nodular thyroid gland) increased the sensitivity of subtraction PS. SPECT/low-dose CT did not increase sensitivity but aided in the exact localization of the HPGs. Of 7 negative subtraction PS studies, 4D-CT and US were able to locate 3 and 1 additional HPGs, respectively.
  
  
  CONCLUSIONS
  Dual isotope pinhole subtraction PS has higher diagnostic accuracy compared with dual-phase PS, 4D-CT, and US as a first-line imaging study in primary hyperparathyroidism. In case of a negative scintigraphy or suspicion of multiglandular disease, 4D-CT and/or US is recommended as a second-line modality. However, diagnostic algorithms should be adapted in accordance with local availability and expertise.
authors.affiliation: From the Departments of *Nuclear Medicine and †Radiology, Gentofte University Hospital, Hellerup; ‡Department of Otolaryngology, Head and Neck Surgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen; and §Department of Endocrinology, Herlev University Hospital, Herlev, Denmark.
authors.forename: Martin
authors.initials: M
authors.lastname: Krakauer
authors.forename: Bente
authors.initials: B
authors.lastname: Wieslander
authors.forename: Peter S
authors.initials: PS
authors.lastname: Myschetzky
authors.forename: Anke
authors.initials: A
authors.lastname: Lundstrøm
authors.forename: Theis
authors.initials: T
authors.lastname: Bacher
authors.forename: Christian H
authors.initials: CH
authors.lastname: Sørensen
authors.forename: Waldemar
authors.initials: W
authors.lastname: Trolle
authors.forename: Birte
authors.initials: B
authors.lastname: Nygaard
authors.forename: Finn N
authors.initials: FN
authors.lastname: Bennedbæk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi