Document Detail

Physiological basis of myocardial perfusion imaging with the technetium 99m agents.
MedLine Citation:
PMID:  1835136     Owner:  NLM     Status:  MEDLINE    
In recent years, several technetium 99m-labeled myocardial perfusion agents have been under investigation to determine their utility in assessing regional myocardial blood flow and cellular viability. 99mTc sestamibi (2-methoxyisobutyl isonitrile), one of the most promising of these agents, is a lipophilic cation that is sequestered largely within mitochondria by the large negative transmembrane potential. Experimental studies have shown that this agent is taken up in the myocardium in proportion to blood flow, but like other diffusible radionuclides underestimates flow at high flow rates. Fractional extraction (Emax) for 99mTc sestamibi is lower than that for thallium 201, but net myocardial uptake is comparable between the two radionuclides. Compared with 201Tl, 99mTc sestamibi does not significantly redistribute. Studies have shown that 99mTc sestamibi uptake after reperfusion, preceded by varying periods of coronary occlusion, reflects the degree of myocardial salvage and viability. 99mTc teboroxime, another promising new perfusion agent, is a boronic acid adduct of technetium dioxime complexes. Emax of 99mTc teboroxime is higher than Emax for 201Tl, but myocardial washout is very rapid (half-life = 21 minutes). Myocardial uptake is proportional to regional flow as found with 99mTc sestamibi and 201Tl.
G A Beller; D D Watson
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Publication Detail:
Type:  Comparative Study; Journal Article; Review    
Journal Detail:
Title:  Seminars in nuclear medicine     Volume:  21     ISSN:  0001-2998     ISO Abbreviation:  Semin Nucl Med     Publication Date:  1991 Jul 
Date Detail:
Created Date:  1991-11-27     Completed Date:  1991-11-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1264464     Medline TA:  Semin Nucl Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  173-81     Citation Subset:  IM    
Department of Medicine, University of Virginia Health Sciences Center, Charlottesville 22908.
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MeSH Terms
Coronary Circulation
Coronary Disease / metabolism,  radionuclide imaging
Heart / radionuclide imaging*
Myocardium / metabolism*
Nitriles / diagnostic use,  pharmacokinetics*
Organotechnetium Compounds / diagnostic use,  pharmacokinetics*
Oximes / diagnostic use,  pharmacokinetics*
Technetium Tc 99m Sestamibi
Thallium Radioisotopes / diagnostic use
Reg. No./Substance:
0/Nitriles; 0/Organotechnetium Compounds; 0/Oximes; 0/Thallium Radioisotopes; 104716-22-5/technetium Tc 99m teboroxime; 109581-73-9/Technetium Tc 99m Sestamibi
Comment In:
Semin Nucl Med. 1991 Jul;21(3):170-2   [PMID:  1835135 ]

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