ECG-gated and static technetium-99m-SESTAMIBI planar myocardial perfusion imaging: a comparison with thallium-201 and study of observer variabilities.

To assess the diagnostic accuracy of planar diastolic and static Technetium-99m-SESTAMIBI, myocardial perfusion imaging at rest and during exercise, was performed in 60 consecutive patients. The results were compared with coronary angiographic findings, obtained within 3 months of the exercise test and Thallium-201 images, obtained on the same day and to the same exercise level as Technetium-99m-SESTAMIBI exercise. Exact segmental concordance between static Technetium-99m-SESTAMIBI and Thallium-201 was 77% and between the diastolic images and Thallium-201 76%. Concordance between static and diastolic images was 92%. Nineteen percent of all 900 segments demonstrated ischemia with both static and diastolic Technetium-99m-SESTAMIBI and 20% with Thallium-201. Overall sensitivity to detect hemodynamically significant coronary artery disease with static Technetium-99m-SESTAMIBI was 86%, specificity 78%, with diastolic images 89% and 70% and with Thallium-201 89% and 78% (differences not significant). Vessel-specific comparative detection rates revealed no statistical significant differences between both radiopharmaceuticals as well. Intra-observer variability for the static images was 12%, for the diastolic images 21% and Thallium-201 14%. Inter-observer variability for the static images was 14%, diastolic images 24%, and Thallium-201 17%. Although the physical characteristics of Tc-SESTAMIBI enable to perform high-count density imaging and electrocardiographic gating, no significant differences are found when planar diastolic and static Technetium-99m-SESTAMIBI images are compared with Thallium-201 and are well within observer variabilities.