title: 99mTc sestamibi myocardial perfusion scintigraphy with the novel use of metamizol for the detection of perfusion reversibility.
abstract: OBJECTIVE
  This study aims to investigate whether induction with metamizol, an analgesic-antipyretic drug having spasmolitic activity, could be used to increase the detectability of ischemic/jeopardized myocardium during MPS (myocardial perfusion scintigraphy).
  
  
  METHODS
  Metamizol-enhanced rest MPS (45 min after administration of 1 g metamizol orally, 740 MBq (99m)Tc sestamibi was injected, MPS was acquired 45 min later) was performed in 21 patients who had perfusion defects on their previous stress-rest (99m)Tc sestamibi MPS. Blood pressure was monitored at 15-min intervals. Stress, rest, metamizol-rest MPS images were interpreted on the model of 20 segments using a visual uptake score (VUS; 0 = normal, 1 = mild, 2 = moderate, 3 = significant decreases, 4 = no uptake). (99m)Tc sestamibi uptake ratios (MIBI-UR; mean counts in the region of the perfusion defect/mean counts in the region of the normal-perfused wall) were obtained on each MPS and compared with each other. Average MIBI-UR in each scintigraphic examination was calculated. MPS were compared with coronary angiography results.
  
  
  RESULTS
  VUS and MIBI-UR results showed that metamizol-rest MPS displayed the defect reversibility better than rest MPS. Of the 14 segments with fixed perfusion defects on stress-rest MPS, 8 showed improvement of perfusion after metamizol induction. In 33 segments, lesion reversibility was better delineated on metamizol-rest MPS. Metamizol-induced sestamibi uptake was significantly higher (p < 0.001) than stress/baseline rest examinations as calculated by the MIBI-UR. Blood pressure remained unaltered. Coronary angiography results were in concordance with metamizol induced MPS.
  
  
  CONCLUSIONS
  Metamizol-enhanced rest MPS increases detectability of ischemic/viable myocardium during MPS. Metamizol should be discontinued like nitrates before stress MPS since it may mask the visualization of ischemic perfusion defects.
authors.affiliation: Department of Nuclear Medicine, School of Medicine, Hacettepe University, 06100 Sihhiye, Ankara, Turkey. eergul@hacettepe.edu.tr
authors.forename: Eser Lay
authors.initials: EL
authors.lastname: Ergün
authors.forename: Meltem
authors.initials: M
authors.lastname: Caglar
authors.forename: Murat Fani
authors.initials: MF
authors.lastname: Bozkurt
authors.forename: Hakan
authors.initials: H
authors.lastname: Ergün
mesh_terms: D000368:Aged; D018712:Analgesics, Non-Narcotic; D004177:Dipyrone; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology
chemical_list: D018712:Analgesics, Non-Narcotic; D019275:Radiopharmaceuticals; D004177:Dipyrone; D017256:Technetium Tc 99m Sestamibi