title: Early planar and early SPECT Tc-99m sestamibi imaging: can it replace the dual-phase technique for the localization of parathyroid adenomas by omitting the delayed phase?
abstract: OBJECTIVE
  To evaluate whether an early protocol (EP) (early planar and early SPECT) with Tc-99m sestamibi could demonstrate the delayed image of the established dual-phase scintigraphy unnecessary without any decrease in sensitivity for the localization of parathyroid adenomas.
  
  
  METHODS
  A study was carried out in 80 consecutive patients with primary hyperparathyroidism (65 women; mean age, 61.8±14.2 years). Final diagnosis by surgery was possible in 79 patients and confirmed parathyroid adenoma in 76 patients, 1 hyperplasic gland in 1 patient, 2 hyperplasic glands in 1 patient, and differentiated thyroid carcinoma in another patient. Ten minutes after intravenous injection of 740 MBq (20 mCi) of Tc-99m sestamibi, a planar image followed by a SPECT and a 2 to 3 hours delayed planar image were acquired. Two sets of images were evaluated, one without (EP) and the other with the delayed image (dual-phase protocol [DPP]). An abnormality rating of 0 to 4 was given to each set and was compared with the final diagnosis.
  
  
  RESULTS
  When any focal uptake, no matter the intensity, was considered positive, that is setting the threshold in the abnormality rating 1, 71 of the 76 adenomas were correctly localized by DPP and EP (sensitivity: 93.4%).
  
  
  CONCLUSIONS
  The delayed planar image could be omitted without any loss in sensitivity for the localization of parathyroid adenomas, and therefore EP could replace DPP.
authors.affiliation: S. Medicina Nuclear, Hospital Universitario Marqués de Valdecilla, Universidad de Cantabria, Santander, Spain. mimartinez@humv.es
authors.forename: Isabel
authors.initials: I
authors.lastname: Martínez-Rodríguez
authors.forename: Ignacio
authors.initials: I
authors.lastname: Banzo
authors.forename: Remedios
authors.initials: R
authors.lastname: Quirce
authors.forename: Julio
authors.initials: J
authors.lastname: Jiménez-Bonilla
authors.forename: Humberto
authors.initials: H
authors.lastname: Portilla-Quattrociocchi
authors.forename: Pamela
authors.initials: P
authors.lastname: Medina-Quiroz
authors.forename: María
authors.initials: M
authors.lastname: De Arcocha
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Carril
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010282:Parathyroid Neoplasms / Q000000981:diagnostic imaging*; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
chemical_list: D017256:Technetium Tc 99m Sestamibi