Prognostic value of normal myocardial perfusion images using technetium-99m based compounds

Full text: The prognostic value of 201Tl myocardial perfusion imaging is well established. The purpose of this study was to describe the clinical outcome of patients with known or suspected ischemic heart disease and a normal myocardial perfusion scan using 99mTc labelled agents (Sestamibi/Tetrofosmin). Fifty-three patients (29 males, 24 females, mean age 51.58 years) with known or suspected coronary artery disease (CAD) were stressed (3 with dipyridamole and 50 with bicycle ergometer) and gated SPECT myocardial perfusion scan obtained with triple head gamma camera. All patients had normal myocardial perfusion and wall motion. Patients were followed up for 21-24 months and follow up data was obtained from telephone interview. Cardiac events were defined as, hard events (myocardial infarct, unstable angina, death) or soft events (angioplasty or other revascularization). ST segment depression occurred in 11 (20.75%), 6 (11.32%) had pre-test angiographically significant CAD, 4 (7.55%) were studied post CABG and 3 (5.6%) patients had a normal post scan angiography. Cardiac events occurred in none of the patients. Our study confirms the benign outcome of patients with normal myocardial perfusion scan using 99mTc labelled agents, even in patients with angiographically significant CAD, consistent with prior observation for 201Tl cardiac imaging. The lesser number of patients who underwent coronary angiography following a normal perfusion scan shows the determination by treating physicians, that no further evaluation was necessary