title: Dynamic MDCT for localization of occult parathyroid adenomas in 26 patients with primary hyperparathyroidism.
abstract: OBJECTIVE
  The objective of our study was to evaluate the accuracy of dynamic contrast-enhanced 4D MDCT in the preoperative identification of parathyroid adenomas in patients with primary hyperparathyroidism (PHPT) and a history of failed surgery or unsuccessful localization on standard imaging.
  
  
  METHODS
  Thirty-four patients with PHPT underwent 4D CT. Retrospective blinded review of the 4D CT examinations was performed by three radiologists for the presence and location of a suspected parathyroid adenoma or adenomas. At the time of the study, 25 patients underwent surgical exploration after 4D CT. Twenty patients had solitary parathyroid adenomas, two patients had two adenomas resected, two patients did not have an adenoma, and one patient had mild four-gland hyperplasia. One patient did not have PHPT on repeat serum biochemistry. Surgical and pathology reports, adenoma enhancement, and biochemical and clinical follow-up were reviewed. Data were compared with 4D CT interpretations and interobserver reliability was calculated.
  
  
  RESULTS
  The mean sensitivity and specificity of the three readers for the precise CT localization of adenomas was 82% (range, 79-88%) and 92% (range, 75-100%), respectively. Overall interobserver reliability was excellent (κ = 0.70; range, κ = 0.60-0.79). All adenomas resected at surgery showed a biochemical response and clinical response. The mean densities of the confirmed adenomas were 41, 128, 138, and 109 HU at 0, 30, 60, and 90 seconds, respectively. Level II lymph nodes identified in 10 patients showed significantly less enhancement at 30 (p = 0.0001) and 60 (p = 0.006) seconds compared with surgically proven adenomas.
  
  
  CONCLUSIONS
  Occult parathyroid adenoma shows characteristic early enhancement. In this subset of patients, 4D CT may improve surgical outcomes and decrease morbidity.
authors.affiliation: Department of Diagnostic Imaging, Rhode Island Hospital, 593 Eddy St., Providence, RI 02903, USA. mbeland@lifespan.org
authors.forename: Michael D
authors.initials: MD
authors.lastname: Beland
authors.forename: William W
authors.initials: WW
authors.lastname: Mayo-Smith
authors.forename: David J
authors.initials: DJ
authors.lastname: Grand
authors.forename: Jason T
authors.initials: JT
authors.lastname: Machan
authors.forename: Jack M
authors.initials: JM
authors.lastname: Monchik
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D005260:Female; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000000981:diagnostic imaging* / Q000601:surgery; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D016105:Parathyroidectomy; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D007472:Iohexol