GATED TC-99M SESTAMIBI FOR SIMULTANEOUS ASSESSMENT OF STRESS MYOCARDIAL PERFUSION, POSTEXERCISE REGIONAL VENTRICULAR-FUNCTION AND MYOCARDIAL VIABILITY - CORRELATION WITH ECHOCARDIOGRAPHY AND REST TL-201 SCINTIGRAPHY

Objectives. This study compares technetium-99m sestamibi (sestamibi) e lectrocardiographic (ECG) gated single photon emission computed tomogr aphy (gated SPECT) and echocardiography for the evaluation of myocardi al function and assesses the feasibility of single-injection, single a cquisition stress perfusion/rest function technetium-99m sestamibi gat ed SPECT as an alternative to conventional stress/rest imaging for ass essment of myocardial dial perfusion and viability. Background. Simult aneous assessment of stress perfusion and rest function is possible wi th gated SPECT acquisition of stress-injected technetium-99m sestamibi . Methods. Rest thallium-201 SPECT followed by stress sestamibi gated SPECT (acquired 0.5 to 1 h after sestamibi injection) was performed in 58 patients. Echocardiography was performed immediately after or befo re gated SPECT in 43 of the patients. All studies were analyzed by sem iquantitative visual scoring. Sestamibi gated SPECT studies were read for stress perfusion and rest wad motion and thickening. Reversibility on sestamibi gated SPECT was defined as the presence of a definite st ress defect with normal or mildly impaired wall motion or thickening o n gated SPECT. Results. There was high segmental score agreement betwe en gated SPECT and echocardiography for wail motion (91%, kappa = 0.68 , p < 0.001) and thickening (90%, kappa = 0.62, p < 0.001). Correlatio n for global wall motion (r = 0.98, p < 0.001) and thickening (r = 0.9 6, p < 0,001) scores between the two modalities was excellent. In 32 p atients without previous myocardial infarction, there was excellent ag reement for reversibility between stress sestamibi-gated SPECT and res t thallium-201/stress sestamibi (98%, kappa = 0.93, p < 0.01). However , in 26 patients with previous infarction, discordance between the two approaches was frequent, with 26% (20 of 78) of nonreversible defects by stress sestamibi-gated SPECT being reversible by rest thallium-201 /stress sestamibi and 21% (23 of 112) of reversible defects by stress sestamibi-gated SPECT being nonreversible by rest thallium-201/stress sestamibi. Conclusions. Gated SPECT of stress injected sestamibi corre lates well with echocardiographic assessment of regional function and thus adds information to perfusion SPECT. In patients without previous myocardial infarction, a single-injection stress perfusion/rest funct ion approach using sestamibi-gated SPECT can substitute for convention al stress/rest myocardial perfusion imaging, adding a rest perfusion s tudy only if there are nonreversible defects or consideration of atten uation artifacts. In patients with previous myocardial infarction, the gated SPECT approach does not replace the need for a rest perfusion s tudy.