title: Effect of calcium channel blockers on the sensitivity of preoperative 99mTc-MIBI SPECT for hyperparathyroidism.
abstract: BACKGROUND
  Technetium 99m ( 99m Tc)-methoxyisobutylisonitrile (MIBI) single photon emission computed tomography (SPECT) is frequently used in the evaluation of patients with hyperparathyroidism. Calcium channel blockers (CACBs) may affect 99m Tc-MIBI uptake by parathyroid cells. This study examines the effect of CACB therapy on the sensitivity of 99m Tc-MIBI SPECT localization for hyperparathyroidism.
  
  
  METHODS
  Two hundred fifty-three operated patients with hyperparathyroidism were retrospectively reviewed. The potential effect of CACB therapy on 99m Tc-MIBI scan sensitivity was examined by using logistic regression analysis. Possible confounding factors were considered.
  
  
  RESULTS
  Among 235 patients, those with multiple endocrine neoplasia, type I (MEN-I), MEN-IIA, 4-gland hyperplasia, secondary hyperparathyroidism, and tertiary hyperparathyroidism exhibited no difference associated with CACB use. Of the remaining 198 patients with primary hyperparathyroidism, 7/30 (23%) with negative 99m Tc-MIBI SPECT scans compared to 24/168 (14%) with positive scans used CACBs. After correcting for age, gender and gland weight, the odds ratio (OR) for a negative study in patients taking CACBs was 2.88 (95% CI, 1.03-8.10; P = .045). Atherosclerosis, hypertension, diabetes mellitus, preoperative calcium and parathyroid hormone levels, and thyroid hormone use were not confounding factors.
  
  
  CONCLUSIONS
  CACB therapy reduces the sensitivity of 99m Tc-MIBI parathyroid SPECT in patients with primary hyperparathyroidism. Further studies are required to determine the potential reversibility of this effect with termination of CACB therapy.
authors.affiliation: Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
authors.forename: Kent
authors.initials: K
authors.lastname: Friedman
authors.forename: Helina
authors.initials: H
authors.lastname: Somervell
authors.forename: Pavni
authors.initials: P
authors.lastname: Patel
authors.forename: Genevieve B
authors.initials: GB
authors.lastname: Melton
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Garrett-Mayer
authors.forename: Alan P B
authors.initials: AP
authors.lastname: Dackiw
authors.forename: A Cahid
authors.initials: AC
authors.lastname: Civelek
authors.forename: Martha A
authors.initials: MA
authors.lastname: Zeiger
mesh_terms: D002121:Calcium Channel Blockers / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010280:Parathyroid Glands / Q000187:drug effects*; D016105:Parathyroidectomy; D011300:Preoperative Care; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D002121:Calcium Channel Blockers; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi