IMAGING OF ACUTE MYOCARDIAL INFARCTION: A HISTORICAL PERSPECTIVE

• Hg-197 compounds
   

• Tc-99m tetracycline
   

• Tc-99m glucoheptonate
   

• Tc-99m pyrophosphate
   

• Tc-99m antimyosin antibody
   

•  In-111 antimyosin antibody

Tc-99m PYROPHOSPHATE FOR IMAGING OF ACUTE MIs

• Ideal imaging isotope
   
• Minimal radiation dose to patient
   
• Images acute infarcts only, not ischemic areas
   
• Readily available, inexpensive, simple to prepare
   
• Reliably detects AMIs within 1-6 days post infarct, ideally 24-72 hours post infarct
   
• Mechanism involves binding of Tc-PYP to hydroxyapatite crystals formed when circulating phosphate combines with Ca²⁺ ions entering cells at time of cell death

In-111 ANTIMYOSIN ANTIBODY FOR IMAGING ACUTE MIs

• F _AB antibody fragment
   
• Specific for myocardial necrosis
   
• Not a flow marker
   
• Image at 16-24 hours
   
• Positive up to 14 days post-MI

THE PURPOSE OF USING INFARCT AVID AGENTS: To evaluate patients presenting with chest pain of uncertain etiology; clinical indications could include any of the following:

• atypical chest pain
   
• conduction disturbances
   
• non-q-wave infarction
   
• late clinical presentation
   
• post-CABG

Clinical Indications

• Post-thrombolysis
   
• Post-cardioversion
   
• Chest trauma
   
• Extensive localization of q-wave infarction