Detection sensitivity of coronary artery stenosis by 99mTc-sestamibi and 201T1 in canine models of partial and subcritical stenosis.
This study was designed to assess the sensitivity of the monocationic 99mTc-hexakis-2-methoxy, 2-methylpropylisonitrile (99mTc-sestamibi) as compared to 201T1 in the detection of regional myocardial blood flow deficits in dogs with different degrees of stenosis with or without dipyridamole. Regional myocardial distribution of 99mTc-sestamibi and 201Tl was determined in mongrel dogs under different levels of left arterial descending coronary artery (LAD) stenosis (30-45, 60-70 and 100% flow reduction) as monitored with electromagnetic flow probes and radiolabeled microspheres. Both 99mTc-sestamibi and 201Tl distribute in direct proportion to blood flow at all levels of stenosis (r2 = 0.90-0.99). Quantitatively, both tracers underestimate the resting flow stenosis. The regional myocardial distribution for both 99mTc and 201Tl was also determined in subcritically stenosed mongrel dogs. This was produced by placing a balloon cuff around the LAD, infusing dipyridamole to peak hyperemic flow and immediately stenosing the LAD to basal flow. Stenosed to normal zone flow ratios were 0.68 +/- 0.01 compared to 99mTc and 201Tl ratios of 0.73 +/- 0.04 and 0.80 +/- 0.05, respectively. These data suggest that 99mTc is at least as sensitive as 201Tl in the detection of different degrees of critical and subcritical coronary artery stenosis.
Mousa
S A
SA
Du Pont Merck Pharmaceutical Company, Diagnostic Imaging Division, Billerica, Mass.
Cooney
J M
JM
D000818:Animals; D002860:Chromium Radioisotopes; D003327:Coronary Disease / Q000139:chemically induced / Q000000981:diagnostic imaging*; D004176:Dipyridamole; D004195:Disease Models, Animal; D004285:Dogs; D055590:Electromagnetic Phenomena; D008297:Male; D008863:Microspheres; D009570:Nitriles; D015609:Organotechnetium Compounds; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes
D002860:Chromium Radioisotopes; D009570:Nitriles; D015609:Organotechnetium Compounds; D013794:Thallium Radioisotopes; D004176:Dipyridamole; D017256:Technetium Tc 99m Sestamibi