POTENTIAL AND LIMITATION OF MYOCARDIAL PE RFUSION SCINTIGRAPHY FOR DETECTION OF VIABILITY

Scintigraphic detection of myocardial viability is required for treatm ent planning and prognostication in patients with contractile dysfunct ion. There are four pathophysiological entities of dysfunction in coro nary artery disease; one of them, ''hibernating'' myocardium, cannot b e differentiated from scar or necrosis by mere perfusion imaging. Due to the determinants of delayed activity distribution after Tl-201 inje ction, optimized imaging protocols using this tracer allow for adequat e differentiation in many instants. Differentiation between ''stunned' ' and ''hibernating'' myocardium or scar is achieved with all perfusio n indicators actually available. Though Tl-201 imaging with optimized protocols is almost as efficacious in viability detection as F-18-FDG positron emission tomography, the latter actually remains the referenc e method particularly in patients with severe left ventricular dysfunc tion at coronary occlusions.