title: Radiographic evaluation of non-localizing parathyroid adenomas.
abstract: OBJECTIVE
  Patients with primary hyperparathyroidism routinely undergo preoperative imaging to localize the abnormal gland to facilitate a guided parathyroidectomy. These techniques include neck ultrasound (US), dual phase planar technetium-99m ((99m)TC) sestamibi (MIBI) scans, single photon emission computed tomography (SPECT), combined SPECT/CT, and four dimensional CT scans (4D CT). Despite appropriate preoperative imaging, non-localization of abnormal glands does occur. This study aims to determine whether non-localization is the result of radiologic interpretive error or a representation of a subset of truly non-localizing parathyroid adenomas.
  
  
  METHODS
  A retrospective study was performed; two senior radiologists reinterpreted the preoperative imaging (US and MIBI scans) of 30 patients with initially non-localizing studies. All patients underwent parathyroidectomy for primary hyperparathyroidism at a tertiary referral center. Both radiologists were blinded to the scores of his colleague. The results were compared for inter-reader reliability using Cohen's kappa test.
  
  
  RESULTS
  Twenty-nine of thirty nuclear studies were found to be negative on reinterpretation. The readers agreed in 86.67% of their observations, with a kappa (κ) value of 0.706 (SE=±0.131, 95% confidence interval for κ =0.449-0.962). One of eighteen ultrasounds had positive localizations on reexamination, however, the inter-observer agreement was only 55.6%, with a kappa value of 0.351 (SE=±0.139, and 95% confidence interval for κ =0.080-0.623). Overall, no statistically significant difference in preoperative and retrospective interpretation was found.
  
  
  CONCLUSIONS
  This study identifies a subset of parathyroid adenomas that do not localize on preoperative imaging despite sound radiographic evaluation.
authors.affiliation: Division of Otolaryngology Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA.
authors.forename: Sakeena J
authors.initials: SJ
authors.lastname: Payne
authors.affiliation: Division of Otolaryngology Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA.
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Smucker
authors.affiliation: Department of Radiology, The Pennsylvania State University, College of Medicine, Hershey, PA, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Bruno
authors.affiliation: Department of Radiology, The Pennsylvania State University, College of Medicine, Hershey, PA, USA.
authors.forename: Louis S
authors.initials: LS
authors.lastname: Winner
authors.affiliation: Division of General Surgery Subspecialties and Surgical Oncology, Department of Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Saunders
authors.affiliation: Division of Otolaryngology Head and Neck Surgery, The Pennsylvania State University, College of Medicine, Hershey, PA, USA. Electronic address: dgoldenberg@hmc.psu.edu.
authors.forename: David
authors.initials: D
authors.lastname: Goldenberg
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D016105:Parathyroidectomy / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler / Q000379:methods
chemical_list: D017256:Technetium Tc 99m Sestamibi