Usefulness of thallium-201 re-injection method for the evaluation of myocardial viability.
Areas of the heart which are supposedly absent of myocardial viability due to persistent thallium defect in exercise thallium myocardial scintigraphy sometimes recover ventricular wall motion through coronary revascularization. To avoid such underestimation of myocardial viability, a "re-injection method" was developed. At the peak of supine ergometer exercise in 51 patients with coronary artery disease, 111 MBq thallium was injected. Conventional exercise and 3 h-delay images were then obtained using single photon emission computed tomography. Subsequently, 55 MBq thallium was injected and a re-injection image was obtained 1 h later. Each image was divided into 12 segments and compared by left ventriculography and coronary angiography. Redistribution was found in 36 patients (71%) on the delayed images and in 44 patients (86%) on either the delayed or the re-injection images (p < 0.05). There were 127 redistribution segments (38%) on the delayed images and 163 (49%) on the re-injection images out of 336 defects on the exercise images (p < 0.001). In normokinetic segments with significant coronary stenosis and in hypokinetic segments, redistribution was found in 42% and 45% of the defects, respectively, on the delayed images, and in 65% and 62% of the defects, respectively, on the re-injection images (p < 0.01). However, no significant differences were observed between the delayed and either the delayed or re-injection images in the akinetic segments. These results suggest that the re-injection method is useful for avoiding underestimation of myocardial viability.
Second Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
Y
Y
Araki
K
K
Imai
Y
Y
Nishio
S
S
Saito
Y
Y
Ozawa
T
T
Yasugi
H
H
Oka
D000368:Aged; D002470:Cell Survival; D003327:Coronary Disease / Q000000981:diagnostic imaging; D005069:Evaluation Studies as Topic; D005080:Exercise Test / Q000379:methods; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods* / Q000592:standards*; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000166:cytology*; D013794:Thallium Radioisotopes
D013794:Thallium Radioisotopes