Data Sheet 1_Incremental value of dedicated [201Tl] cadmium-zinc-telluride thallium SPECT over rest/stress [99mTc] technetium sestamibi SPECT MPI: a comparative analysis of fixed perfusion defects.docx

However, fixed defects on standard MPI present a well-documented clinical challenge, as they can represent either non-viable scars or viable hibernating myocardium. We aimed to examine the incremental value and rate of diagnostic reclassification provided by performing subsequent dedicated cadmium-zinc-telluride (CZT) [²⁰¹Tl]thallium myocardial SPECT in patients presenting with fixed defects on standard sestamibi MPI.</p>Methods<p>In this retrospective study, we analyzed 174 patients—totaling 2,958 myocardial segments—who underwent both protocols.

Intermodality correlation was assessed, and the rates of segmental and patient-level reclassification (segments converting from <50% maximum uptake on sestamibi to ≥50% maximum uptake on thallium) were quantified.</p>Results<p>While a moderately high correlation was observed between the baseline uptake scores of the two modalities (Spearman's r = 0.817 for rest sestamibi vs. thallium), thallium imaging provided substantial additional information, with 48.0% of segments classified as fixed defects on sestamibi SPECT demonstrating improved uptake on thallium SPECT.