COMBINED REST TL-201 STRESS TECHNETIUM-99M-TETROFOSMIN SPECT - FEASIBILITY AND DIAGNOSTIC-ACCURACY OF A 90-MINUTE PROTOCOL

Technetium-99m tetrofosmin is a recently developed compound that clear s from background organs rapidly. Tetrofosmin has a good correlation w ith Tl-201. This study assesses the feasibility and diagnostic accurac y of a combined protocol involving rest Tl-201 SPECT and stress imagin g with Tc-99m-tetrofosmin. Methods: Twenty-five patients (23 men, 2 wo men; aged 36-73 yr) with known coronary artery disease underwent the c ombined protocol. Twenty minutes after the resting injection of Tl-201 , resting SPECT data were acquired using low-energy, high-resolution c ollimators. A stress test using adenosine infusion combined with low-l evel dynamic exercise was performed. The stress data were collected 20 min later. The reconstructed vertical long-axis, horizontal long-axis and short-axis slices were analyzed qualitatively. Analysis was carri ed out using nine segments of the left ventricle. The segments were re ported either as fixed or reversible. The results were compared to cor onary angiography results. Results: The sensitivity and specificity fo r the detection of diseased coronary vessels were 85% and 70% for the left anterior descending territory, respectively, 78% and 71% for the right coronary artery, and 69% and 70% for the left circumflex. Overal l, the sensitivity was 80% and the specificity 70%. Conclusion: Combin ed rest Tl-201/stress Tc-99m-tetrofosmin SPECT provides a protocol of short duration which displays similar diagnostic accuracy to a protoco l using tetrofosmin as a single agent.