title: Feasibility of tomographic 99mTc-hexakis-2-methoxy-2-methylpropyl-isonitrile imaging for the assessment of myocardial area at risk and the effect of treatment in acute myocardial infarction.
abstract: 99mTc-hexakis-2-methoxy-2-methylpropyl-isonitrile (Tc-Sestamibi), a new myocardial perfusion radiopharmaceutical, was injected intravenously in 11 patients within 4 hours of the onset of acute myocardial infarction before treatment with intravenous tissue-type plasminogen activator and 6-14 days later. Five patients with acute myocardial infarction who did not receive intravenous thrombolytic therapy underwent a similar injection of radiopharmaceutical. The absence of redistribution of Tc-Sestamibi permitted imaging with single-photon emission computed tomography up to 6 hours after intravenous injection to assess the distribution of myocardial perfusion at the time of administration. The region of hypoperfused myocardium on the initial images varied widely from 9% to 68% of the left ventricle and was significantly greater in anterior than in inferior infarcts (p less than 0.01). The region of hypoperfused myocardium on the final images varied widely from 0% to 63% of the left ventricle and was also greater in anterior infarcts (p less than 0.01). The final hypoperfused region correlated (r = -0.82) with the late resting ejection fraction and with the late regional wall motion score in the infarct segment for both anterior (r = -0.74) and inferior (r = -0.97) infarcts. There was a significant decrease (-13 +/- 11%, p less than 0.003) in the extent of hypoperfused myocardium between the initial and final studies in the patients who received thrombolytic therapy compared with an insignificant increase (4 +/- 6%, p greater than 0.5) in the patients who did not receive thrombolytic therapy. Tomographic imaging with Tc-Sestamibi permits determination of the amount of hypoperfused myocardium "at risk" in acute myocardial infarction. The change in myocardial perfusion determined by Tc-Sestamibi before and after therapy in acute myocardial infarction is a promising tool for assessing treatment.
authors.affiliation: Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: R J
authors.initials: RJ
authors.lastname: Gibbons
authors.forename: M S
authors.initials: MS
authors.lastname: Verani
authors.forename: T
authors.initials: T
authors.lastname: Behrenbeck
authors.forename: P A
authors.initials: PA
authors.lastname: Pellikka
authors.forename: M K
authors.initials: MK
authors.lastname: O'Connor
authors.forename: J J
authors.initials: JJ
authors.lastname: Mahmarian
authors.forename: J H
authors.initials: JH
authors.lastname: Chesebro
authors.forename: F J
authors.initials: FJ
authors.lastname: Wackers
mesh_terms: D000368:Aged; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000188:drug therapy; D009570:Nitriles; D015609:Organotechnetium Compounds; D017256:Technetium Tc 99m Sestamibi; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D014055:Tomography, Emission-Computed
chemical_list: D009570:Nitriles; D015609:Organotechnetium Compounds; D017256:Technetium Tc 99m Sestamibi; D010959:Tissue Plasminogen Activator