title: Correlation between serum calcium levels and dual-phase (99m)Tc-sestamibi parathyroid scintigraphy in primary hyperparathyroidism.
abstract: OBJECTIVE
  The goal of the study is to correlate serum calcium levels with the results of dual-phase (99m)Tc-sestamibi parathyroid scintigraphy to find the best cut-off level of the serum calcium that correlates with a positive presurgery.
  
  
  METHODS
  In 111 patients, serum calcium and plasma parathormone (PTH) levels were compared with the results of the (99m)Tc-MIBI scintigraphy and with this data determined the level of calcium above which the (99m)Tc-MIBI scintigraphy was likely to be positive and below which the study was likely to be negative.
  
  
  RESULTS
  In total, 11 men (18%) and 50 women (82%) had a positive (99m)Tc-MIBI study. Overall 67% of those patients with a positive (99m)Tc-MIBI study had a PTH >200 ng l(-1) compared to only 9% of those with a negative (99m)Tc-MIBI scintigraphy; however, for those with a positive study on an early (99m)Tc-MIBI scintigraphy, this rose to 85%. Overall a serum calcium of >2·70 mmol l(-1) was found in 82% of patients with a positive (99m)Tc-MIBI study but only 14% of those with a negative (99m)Tc-MIBI study, this is rose to 97% of patients with a parathyroid adenoma identified on early images. It is also shown that patients whose serum total calcium <2·51 mmol l(-1) rarely have positive (99m)Tc-MIBI scintigraphy.
  
  
  CONCLUSIONS
  (99m)Tc-MIBI parathyroid scintigraphy is most likely to yield identification and localization of a parathyroid adenoma when both PTH and calcium are elevated; however, although there is no lower limit of PTH which can predict a negative study, we cannot recommend (99m)Tc-MIBI parathyroid scintigraphy if the serum calcium is <2·51 mmol l(-1).
authors.affiliation: Department of Nuclear Medicine, Steve Biko Academic Hospital, University of Pretoria, Pretoria, South Africa.
authors.forename: D S
authors.initials: DS
authors.lastname: Mshelia
authors.forename: A N
authors.initials: AN
authors.lastname: Hatutale
authors.forename: N P
authors.initials: NP
authors.lastname: Mokgoro
authors.forename: M E
authors.initials: ME
authors.lastname: Nchabaleng
authors.forename: J R
authors.initials: JR
authors.lastname: Buscombe
authors.forename: M M
authors.initials: MM
authors.lastname: Sathekge
mesh_terms: D000236:Adenoma / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006934:Hypercalcemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D049950:Hyperparathyroidism, Primary / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D010280:Parathyroid Glands / Q000000981:diagnostic imaging* / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000097:blood; D010282:Parathyroid Neoplasms / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D013019:South Africa; D017256:Technetium Tc 99m Sestamibi; D014057:Tomography, X-Ray Computed; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015415:Biomarkers; C470125:PTH protein, human; D010281:Parathyroid Hormone; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D002118:Calcium