Usefulness of reinjection image for evaluating viable myocardium in the infarcted zone on exercise thallium-201 SPECT.
Reinjection images were obtained in 23 patients with myocardial infarction by the additional injection of 37 MBq of thallium-201 after obtaining 4 hour delayed images on exercise thallium-201 SPECT (TSPECT). A redistribution index (RI) was derived of the changes in perfusion defects between immediate and 4 hour delayed images as well as immediate and reinjection images on polar bull's eye maps. The RI of reinjection images (46 +/- 27%) was significantly greater than that of 4 hour delayed images (26 +/- 26%) in patients with myocardial infarction (p less than 0.01). Significant redistribution after reinjection occurred in 4 of 9 patients (44%) without significant redistribution on 4 hour delayed images. Improvement in redistribution on reinjection images correlated significantly to the small extent of coronary artery disease and collateral development. The appearance of redistribution from 4 hour delayed imaging to reinjection imaging also might reflect the function of collateral development in the resting state in patients without significant redistribution on 4 hour delayed images. It has been demonstrated that underestimated viable myocardium on 4 hour delayed images in the infarcted zone can be better assessed on reinjection images. This reinjection technique is recommended in patients with no or partial redistribution on 4 hour delayed images.
Tomiguchi
S
S
Department of Radiology, Kumamoto University School of Medicine, Japan.
Takahashi
M
M
Shimomura
O
O
Kojima
A
A
Hara
M
M
Koga
Y
Y
Minoda
K
K
Yasue
H
H
Hayasaki
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D013794:Thallium Radioisotopes / Q000008:administration & dosage; D013997:Time Factors
D013794:Thallium Radioisotopes