Exercise-rest Tc-99m tetrofosmin SPECT in patients with chronic ischemic left ventricular dysfunction: Direct comparison with TI-201 reinjection

Abstract

Background. This study was designed to compare the results of exercise-rest technetium-99m tetrofosmin single photon emission computed tomography (SPECT) with those of thallium-201 reinjection at rest after exercise-redistribution imaging in the same patients with chronic ischemic left ventricular (LV) dysfunction. Methods. Within 1 week, 33 patients with chronic myocardial infarction and LV dysfunction underwent exercise-rest tetrofosmin SPECT and TI-201 reinjection at rest after exercise-redistribution imaging. In each patient, regional tetrofosmin and TI-201 activity was quantitatively measured in 22 myocardial segments. Regional LV function was assessed in corresponding segments by echocardiography. Results. Agreement in the evaluation of regional perfusion status between tetrofosmin and TI-201 imaging was observed in 78% of the 726 total segments, with a κ value of 0.61. In segments with normal function at echocardiography ( n = 436), no difference between TI-201 and tetrofosmin uptake was observed. In hypokinetic segments ( n = 138), exercise tetrofosmin uptake was lower ( P < .01) as compared with exercise TI-201 activity, whereas no difference was observed between tetrofosmin uptake at rest as compared with TI-201 activity on redistribution and reinjection images. In segments with severe functional impairment (akinetic or dyskinetic, n = 152), tetrofosmin uptake on exercise images was reduced ( P < .01) as compared with exercise TI-201 activity; furthermore, tetrofosmin uptake at rest was lower ( P < .01) as compared with TI-201 activity on both redistribution and reinjection images. In these segments, concordance in the detection of myocardial viability between tetrofosmin and TI-201 imaging was observed in 138 (91%) of the 152 segments, with a κ value of 0.77. Conclusions. In patients with chronic coronary artery disease and LV dysfunction quantitative exercise-rest tetrofosmin and TI-201 reinjection SPECT provide similar information in the assessment of perfusion status and in the detection of myocardial viability.