title: Serial quantitative planar technetium-99m isonitrile imaging in acute myocardial infarction: efficacy for noninvasive assessment of thrombolytic therapy.
abstract: Technetium-99m isonitrile is a new myocardial perfusion imaging agent that accumulates according to the distribution of myocardial blood flow. However, unlike thallium-201, it does not redistribute over time. This imaging agent was used with serial quantitative planar imaging to assess the initial risk area of infarction, its change over time and the relation to infarct-related artery patency in 30 patients with a first acute myocardial infarction. Twenty-three of 30 patients were treated with recombinant tissue-type plasminogen activator (rt-PA) within 4 h after the onset of chest pain. Seven patients were treated in the conventional manner without thrombolytic therapy. Technetium-99m isonitrile was injected before or at the initiation of thrombolytic therapy, and imaging was performed several hours later. These initial images demonstrated the area at risk. Repeat imaging was performed 18 to 48 h later and at 6 to 14 days after the onset of myocardial infarction to visualize the ultimate extent of infarction. The initial area at risk varied greatly (range defect integral 2 to 61) both in patients treated with rt-PA and in those who received conventional treatment. For the total group, the initial imaging defect decreased in size in 20 patients and was unchanged or larger in 10 patients. Patients with a patent infarct-related artery had a significantly greater decrease in defect size than did patients with persistent coronary occlusion (-51 +/- 38% versus -1 +/- 26%, p = 0.0001). All patients with a decrease in defect size greater than 30% had a patent infarct-related artery. In 12 patients who also had predischarge quantitative exercise thallium-201 imaging, good agreement existed between the extent and severity of myocardial perfusion defect on the last technetium-99m isonitrile study before discharge and that noted on delayed thallium-201 imaging. It is concluded that serial planar technetium-99m isonitrile myocardial imaging in patients with acute myocardial infarction undergoing thrombolytic therapy offers a new quantitative noninvasive approach for assessment of the initial risk zone as well as the success of reperfusion.
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut 06510.
authors.forename: F J
authors.initials: FJ
authors.lastname: Wackers
authors.forename: R J
authors.initials: RJ
authors.lastname: Gibbons
authors.forename: M S
authors.initials: MS
authors.lastname: Verani
authors.forename: D S
authors.initials: DS
authors.lastname: Kayden
authors.forename: P A
authors.initials: PA
authors.lastname: Pellikka
authors.forename: T
authors.initials: T
authors.lastname: Behrenbeck
authors.forename: J J
authors.initials: JJ
authors.lastname: Mahmarian
authors.forename: B L
authors.initials: BL
authors.lastname: Zaret
mesh_terms: D003287:Contrast Media; 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; D011877:Radionuclide Imaging; D011994:Recombinant Proteins / Q000627:therapeutic use; D017256:Technetium Tc 99m Sestamibi; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*
chemical_list: D003287:Contrast Media; D009570:Nitriles; D015609:Organotechnetium Compounds; D011994:Recombinant Proteins; D017256:Technetium Tc 99m Sestamibi; D010959:Tissue Plasminogen Activator