EVALUATION OF TC-99(M)-TEBOROXIME SCINTIGRAPHY FOR THE DIFFERENTIATION OF REVERSIBLE FROM FIXED DEFECTS - COMPARISON WITH TL-201 REDISTRIBUTION AND REINJECTION IMAGING

The aim of this study was to compare Tc-99m-teboroxime and Tl-201 myoc ardial studies with particular regard to the classification of perfusi on defects as reversible or fixed. Twenty patients with a history of p revious myocardial infarction and suspected effort ischaemia underwent exercise Tl-201 scintigraphy with early (4 h) redistribution and rein jection scans, exercise and rest Tc-99m-teboroxime imaging and coronar y angiography. Using a qualitative scoring of static planar images, th e perfusion defects were classified as reversible or fixed. Tl-201 and Tc-99m-teboroxime gave comparable results in the evaluation of the in dividual vessels (sensitivity 65%, specificity 80% and 85%, respective ly). The stress-redistribution Tl-201 sequence classified 45 defects a s reversible and 28 as fixed, the stress-rest Tc-99m-teboroxime studie s classified 47 as reversible and 26 as fixed (NS). The stress-reinjec tion Tl-201 images, however, characterized 64 defects as reversible an d nine as fixed (P < 0.005 versus Tl-201 redistribution, P < 0.0005 ve rsus Tc-99m-teboroxime rest). In conclusion, this study shows that res t Tc-99m-teboroxime and Tl-201 redistribution give comparable results but that significantly more defects are classified as fixed by Tc-99m- teboroxime than by Tl-201 if reinjection of the latter tracer is perfo rmed.