Technetium 99m SESTAMIBI myocardial perfusion imaging: comparison between treadmill, dipyridamole and trans-oesophageal atrial pacing "stress" tests in normal subjects.

The purpose of this study was to determine the blood clearance, myocardial uptake and heart/lung and heart/liver ratios of technetium 99m methoxyisobutylisonitrile (99mTc-SESTAMIBI) following 3 different types of cardiac stimulation in normal subjects: treadmill stress (STRESS), intravenous administration of dipyridamole (DIP) and trans-oesophageal atrial pacing (TAP). Ten normal volunteers were submitted to 3 injections of 99mTc-SESTAMIBI (10 mCi/70 kg, separated by an interval of 7 days) following STRESS (standard Bruce protocol), DIP (0.142 mg/kg.min during 4 min) and TAP procedures. Blood samples were collected from 1 to 60 min after each 99mTc-SESTAMIBI injection. Planar imaging was performed at 5, 30 and 60 min. Blood retention (percentage of injected dose at 1 min) was 56% +/- 4%, 24% +/- 4% and 38% +/- 6% for STRESS, DIP and TAP, respectively (P less than 0.001). Myocardial uptake was similar for the 3 procedures while the heart lung ratio at 60 min was 3.1 +/- 0.5, 3.8 +/- 0.6 and 3.2 +/- 0.5 for STRESS, DIP and TAP, respectively. Heart/liver ratio at 60 min was 1.9 +/- 0.5, 1.3 +/- 0.3 and 1.1 +/- 0.2 for STRESS, DIP and TAP, respectively (P less than 0.001). These results demonstrated that the 3 types of cardiac stimulation show good imaging parameters with 99mTc-SESTA-MIBI.