title: Optimal pinhole techniques for preoperative localization with Tc-99m MIBI for primary hyperparathyroidism.
abstract: OBJECTIVE
  Technetium-99m-labeled 2-methoxyisobutylisonitrile (Tc-99m MIBI) has been used extensively to localize parathyroid adenomas before operation. Imaging techniques vary widely, and the aim of this study was to determine the optimal time of delayed imaging and the value of routine correlative pertechnetate thyroid imaging.
  
  
  METHODS
  In this study, preoperative parathyroid localization was performed using pinhole anterior and oblique images (15 minutes and 2 and 4 hours after injection) with correlative pertechnetate thyroid images. Ninety-seven patients underwent dual- or triple-phase Tc-99m MIBI imaging and correlative pertechnetate thyroid imaging before surgery. Two nuclear medicine physicians blinded to the surgical findings interpreted all available images and various Tc-99m MIBI image combinations at 15 minutes alone; 15 minutes and 2 hours, 15 minutes and 4 hours; and 15 minutes and 2 and 4 hours each with and without correlative pertechnetate thyroid imaging.
  
  
  RESULTS
  Ninety parathyroid adenomas were detected in 86 patients. The optimal results were achieved with 15-minute and 2- and 4-hour Tc-99m-MIBI images, with correlative thyroid scans resulting in a sensitivity rate of 88%. Fifteen-minute and 2-hour Tc-99m-MIBI images and correlative thyroid scans and 15-minute and 4-hour Tc-99m MIBI images and correlative thyroid scans produced similar results (sensitivity rate, 86% and 83%, respectively; P = not significant). Compared with all Tc-99m MIBI image combinations alone, the addition of the routine correlative thyroid scan significantly improved sensitivity and also improved reporter confidence in 45% of studies.
  
  
  CONCLUSIONS
  Of the pinhole techniques compared, 15-minute and 2-hour Tc-99m MIBI images with correlative thyroid scanning may be the preferred imaging protocol, because this yields results similar to imaging for as long as 4 hours after injection in a shorter, more logistically acceptable imaging time.
authors.affiliation: Department of Nuclear Medicine, Royal North Shore Hospital, Sydney, Australia.
authors.forename: I A
authors.initials: IA
authors.lastname: Ho Shon
authors.forename: P J
authors.initials: PJ
authors.lastname: Roach
authors.forename: E J
authors.initials: EJ
authors.lastname: Bernard
authors.forename: L W
authors.initials: LW
authors.lastname: Delbridge
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000000981:diagnostic imaging; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D011300:Preoperative Care; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D013959:Thyroid Diseases / Q000000981:diagnostic imaging; D013997:Time Factors
chemical_list: D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi