title: 99mTc-HL91 is inferior to 201Tl in scintigraphic detection of chronic myocardial ischaemia.
abstract: OBJECTIVE
  99mTc-HL91 is a new hypoxia agent and can identify acutely ischaemic viable myocardium in a canine model using a standard gamma camera. The purpose of the study was to determine whether this tracer could be used to detect regional ischaemia in chronic ischaemic myocardium in a swine model.
  
  
  METHODS
  Using a porcine model of chronic myocardial ischaemia, five mini-pigs with proximal left anterior descending artery (LAD) stenoses were studied. Injection of 462.5 MBq (12.5 mCi) 99mTc-HL91 was followed by imaging over 2 h. Coronary angiography and dipyridamole stress-re-injection 201Tl single photon emission computed tomography (SPECT) were performed within 1 day of each other.
  
  
  RESULTS
  None of the five pigs demonstrated positive hot 99mTc-HL91 uptake throughout the 2 h imaging, whereas four of the five animals showed significant myocardial ischaemia on 201Tl SPECT. The region of interest analysis of LAD/left circumflex artery count ratios at 1 and 2 h demonstrated similar 99mTc-HL91 uptake and retention in chronic ischaemic as well as non-ischaemic myocardium.
  
  
  CONCLUSIONS
  99mTc-HL91 is inferior to 201Tl in scintigraphic detection of chronic myocardial ischaemia.
authors.affiliation: Departments of Nuclear Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
authors.forename: Yen-Wen
authors.initials: YW
authors.lastname: Wu
authors.forename: Chii-Ming
authors.initials: CM
authors.lastname: Lee
authors.forename: Yi-Hwen
authors.initials: YH
authors.lastname: Huang
authors.forename: Nai-Kuan
authors.initials: NK
authors.lastname: Chou
authors.forename: Ruoh-Fen
authors.initials: RF
authors.lastname: Yen
authors.forename: Kai-Yuan
authors.initials: KY
authors.lastname: Tzen
authors.forename: Por-Jau
authors.initials: PJ
authors.lastname: Huang
mesh_terms: D000792:Angiography; D000818:Animals; D017023:Coronary Angiography; D004452:Echocardiography; D007511:Ischemia / Q000473:pathology; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000473:pathology*; D009206:Myocardium / Q000473:pathology; D015609:Organotechnetium Compounds; D010091:Oximes; D011877:Radionuclide Imaging / Q000295:instrumentation* / Q000379:methods*; D019275:Radiopharmaceuticals; D013552:Swine; D013556:Swine, Miniature; D013794:Thallium Radioisotopes; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
chemical_list: D015609:Organotechnetium Compounds; D010091:Oximes; D019275:Radiopharmaceuticals; D013794:Thallium Radioisotopes; C105527:technetium Tc 99m 4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime