99mTc sestamibi myocardial perfusion scintigraphy with the novel use of metamizol for the detection of perfusion reversibility.
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.
Ergün
Eser Lay
EL
Department of Nuclear Medicine, School of Medicine, Hacettepe University, 06100 Sihhiye, Ankara, Turkey. eergul@hacettepe.edu.tr
Caglar
Meltem
M
Bozkurt
Murat Fani
MF
Ergün
Hakan
H
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
D018712:Analgesics, Non-Narcotic; D019275:Radiopharmaceuticals; D004177:Dipyrone; D017256:Technetium Tc 99m Sestamibi