ASSESSMENT OF MYOCARDIAL VIABILITY BY DYNAMIC TOMOGRAPHIC IODINE-123 IODOPHENYLPENTADECANOIC ACID IMAGING - COMPARISON WITH REST-REDISTRIBUTION THALLIUM-201 IMAGING

Background. This study examined the ability of dynamic I-123-labeled i odophenylpentade-canoic acid (IPPA) imaging to detect myocardial viabi lity in patients with left ventricular (LV) dysfunction caused by coro nary artery disease. Methods and Results. Serial 180-degree single-pho ton emission computed tomographic (SPECT) images (five sets, 8 minutes each) were obtained starting 4 minutes after injection of 2 to 6 mCi I-123 at rest in 21 patients with LV dysfunction (ejection fraction [E F] 34% +/- 11%). The segmental uptake was compared with that of rest-r edistribution (TI)-T-201 images (20 segments/study). The number of per fusion defects (reversible and fixed) was similar by IPPA and thallium (11 +/- 5 vs 10 +/- 5 segments/patient; difference not significant). There was agreement between IPPA and thallium for presence or absence (kappa = 0.78 +/- 0.03) and nature (reversible, mild fixed, or severe fixed) of perfusion defects (kappa = 0.54 +/- 0.04). However, there we re more reversible IPPA defects than reversible thallium defects (7 +/ - 4 vs 3 +/- 4 segments/patient; p = 0.001). In 14 patients the EF (by gated pool imaging) improved after coronary revascularization from 33 % +/- 11% to 39% +/- 12% (p = 0.002). The number of reversible IPPA de fects was greater in the seven patients who had improvement in EF than in the patients without such improvement (10 +/- 4 vs 5 +/- 4 segment s/patient; p = 0.075). Conclusions. I-123-labeled IPPA SPECT imaging i s a promising new technique for assessment of viability. Reversible de fects predict recovery of LV dysfunction after coronary revascularizat ion.