title: Multiphase computed tomography for localization of parathyroid disease in patients with primary hyperparathyroidism: How many phases do we really need?
abstract: BACKGROUND
  Multiphase computed tomography (CT) involves multiple cervical CT acquisitions to accurately identify hyperfunctional parathyroid glands, thus increasing radiation exposure to the patient. We hypothesized that only 2 cervical acquisitions, instead of the conventional 4, would provide equivalent localization information and halve the radiation exposure.
  
  
  METHODS
  We identified 53 consecutive patients with primary hyperparathyroidism who underwent multiphase CT before parathyroidectomy. All scans were reinterpreted first using 2 phases then using all 4 phases. The accuracies of interpretations were determined with surgical findings serving as the standard of reference.
  
  
  RESULTS
  Sixty-four hyperfunctional parathyroid glands were resected with a mean weight of 394.3 mg. Two-phase CT lateralized the hyperfunctional glands in 38 patients with a sensitivity, positive predictive value (PPV), and accuracy of 100%, 71.7%, and 71.7%, respectively. Four-phase CT lateralized the hyperfunctional glands in 39 patients with a sensitivity, PPV, and accuracy of 95.1%, 76.5%, and 73.6%, respectively. For quadrant localization, the accuracy of 2-phase and 4-phase CT was 50.9% and 52.8%, respectively.
  
  
  CONCLUSIONS
  Our results suggest that 2-phase and 4-phase CT provide an equivalent diagnostic accuracy in localizing hyperfunctional parathyroid glands. The reduced radiation exposure to the patient may make 2-phase acquisitions a more acceptable alternative for preoperative localization.
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Salem I
authors.initials: SI
authors.lastname: Noureldine
authors.affiliation: Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Nafi
authors.initials: N
authors.lastname: Aygun
authors.affiliation: Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Walden
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Hassoon
authors.affiliation: Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Sachin K
authors.initials: SK
authors.lastname: Gujar
authors.affiliation: Division of Head and Neck Endocrine Surgery, Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. Electronic address: rtufano@jhmi.edu.
authors.forename: Ralph P
authors.initials: RP
authors.lastname: Tufano
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D010282:Parathyroid Neoplasms / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D016105:Parathyroidectomy / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity