Detecting viable hibernating myocardium in chronic coronary artery disease--a comparison of resting 201Tl single photon emission computed tomography (SPECT), 99mTc-methoxy-isobutyl isonitrile SPECT after nitrate administration, and 201Tl SPECT after 201Tl-glucose-insulin infusion.

To identify and quantify the amount of viable hibernating myocardium in patients with chronic coronary artery disease, resting 201Tl single photon emission computed tomography (SPECT) was compared with 99mTc-methoxy-isobutyl isonitrile (MIBI) SPECT after nitrate infusion (nitrate-99mTc-MIBI) and 201Tl SPECT after 201Tl with glucose-insulin-potassium infusion (201Tl-GIK) in 25 patients. Twenty-one patients also underwent completely left ventriculography beforehand and 5+/-4 months afterwards. SPECT images were divided into 9 segments and scored visually from 0 (normal uptake) to 3 (absent). The defect score was calculated as the summation of the total scores (TDS) in each patient. The TDS of nitrate-99mTc-MIBI images (6.3+/-4.3) and 201Tl-GIK images (5.8+/-4.2) were significantly lower than the 7.4+/-4.3 of resting 201Tl images (p<0.01). Based on the improvement of wall motion after coronary revascularization, the sensitivity of 201Tl-GIK imaging (85%) was significantly higher (p<0.05), and that of nitrate-99mTc-MIBI imaging (79%) also tended to be higher (p=0.08), than that of 201Tl imaging (62%) in detecting viable myocardium. The specificity of the 3 methods was almost the same. The nitrate-99mTc-MIBI and 201Tl-GIK methods were more useful than the resting 201Tl method for evaluating viable hibernating myocardium. Furthermore, the 201Tl-GIK method may provide a more accurate estimate of the amount of viable myocardium than the nitrate-99mTc-MIBI method.