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

Background. This study was designed to compare the results of exercise-rest technetium-99m tetrofosmin single photon emission computed tomography (SPE CT) with those of thallium-201 reinjection at rest after exercise-redistrib ution 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 Tl-201 reinjec tion at rest after exercise-redistribution imaging. In each patient, region al tetrofosmin and Tl-201 activity was quantitatively measured in 22 myocar dial segments, Regional LV function was assessed in corresponding segments by echocardiography, Results. Agreement in the evaluation of regional perfusion status between t etrofosmin and Tl-201 imaging was observed in 78% of the 726 total segments , with a kappa value of 0.61. In segments with normal function at echocardi ography (n = 436), no difference between Tl-201 and tetrofosmin uptake was observed. In hypokinetic segments (n = 138), exercise tetrofosmin uptake wa s lower (P < .01) as compared with exercise Tl-201 activity, whereas no dif ference was observed between tetrofosmin uptake at rest as compared with Tl -201 activity on redistribution and reinjection images. In segments with se vere functional impairment (akinetic or dyskinetic, n = 152), tetrofosmin u ptake on exercise images was reduced (P < .01) as compared with exercise Tl -201 activity; furthermore, tetrofosmin uptake at rest was lower (P < .01) as compared with Tl-201 activity on both redistribution and reinjection ima ges. In these segments, concordance in the detection of myocardial viabilit y between tetrofosmin and Tl-201 imaging was observed in 138 (91%) of the 1 52 segments, with a kappa value of 0.77. Conclusions. In patients with chronic coronary artery disease and LV dysfun ction quantitative exercise-rest tetrofosmin and Tl-201 reinjection SPECT p rovide similar information in the assessment of perfusion status and in the detection of myocardial viability.