ISSN:
1619-7089
Keywords:
Myocardial perfusion
;
Thallium-201
;
Technetium-99m methoxyisobutylisonitrile
;
Viable myocardium
;
Single-photon emission tomography
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract We have compared stress-redistribution and delayed rest thallium-201 with rest technetium-99m methoxyisobutylisonitrile (MIBI) tomograms in order to compare the tracers for the assessment of myocardial viability and to validate a rapid protocol combining the two tracers. We studied 30 consecutive patients with known or suspected coronary artery disease [group 1: 16 with normal left ventricular function, mean left ventricular ejection fraction (LVEF) 55%, SD 6%; group 2: 14 with abnormal function, mean LVEF 28%, SD 8%].201Tl was injected during infusion of adenosine followed by acquisition of conventional stress and redistribution tomograms. On a separate day,201Tl was injected at rest with imaging 4 h later.99mTc-MIBI was then given at rest and imaging was performed. Three images were compared: redistribution201Tl, rest201Tl, and rest99mTc-MIBI. Tracer activity was classified visually and quantitatively in nine segments and segments with〉50% activity were defined as containing clinically significant viable myocardium. Mean (±SD) global tracer uptake as a percentage of maximum was similar in group 1 (rest201Tl 69%±12%, redistribution201Tl 69%±15%, rest99mTc-MIBI 70%±13%, ANOVAP〉0.05), but in group 2 mean tracer uptake was significantly greater in the rest201Tl images (59%±16%) than in redistribution201Tl images (53%±17%) or rest99mTc-MIBI images (53%±19%) (ANOVAP=0.02). Overall agreement for regional uptake score was excellent (κ from 0.79 to 0.84), although there were a significant number of segments with less uptake shown by redistribution201Tl and by rest99mTc-MIBI than by rest201Tl in group 2 (P〈0.001). The number of segments with significant viable myocardium in group 1 was very similar between the three images (P〉0.05) but in group 2 rest201Tl identified significantly more segments as viable than the other images (McNemarP〈0.001). Thus201Tl and99mTc-MIBI provide similar information in patients without prior infarction and with normal left ventricular function (group 1), and a rapid protocol with stress201Tl injection and imaging followed immediately by rest99mTc-MIBI injection and imaging is feasible. In patients with abnormal left ventricular function and prior infarction (group 2),99mTc-MIBI may underestimate the extent of clinically significant viable myocardium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00808415
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