Hypoxia imaging of patients with acute myocardial infarction by using dual isotopes of 201Tl and 99mTc-HL91.
OBJECTIVE
To evaluate the myocardial ischaemia/viability in patients with acute myocardial infarction (AMI) using the ischaemia-avid agent (99m)Tc-HL91.


METHODS
Thirty-three AMI patients received 740 MBq (20 mCi) (99m)Tc-HL91, i.v., first and then 148-185 MBq (4-5 mCi) (201)Tl around 3 h later. The patient underwent initial imaging and 24 h late imaging, 10-15 min and 24 h later, respectively, after intravenous injection of (201)Tl. Myocardial segmental radioactive counts of (99m)Tc-HL91 were quantified by the region of interest technique. The segmental radioactive counts/pixel divided by those of the corresponding left ventricular cavities were ratios, which were compared among normal, ischemic/viable and fixed defect myocardium. The correlation analysis between the segmental scores from (201)Tl imaging and the ratios was performed.


RESULTS
The cross-talk of (99m)Tc into (201)Tl could be neglected in the present study. Out of the 33 AMI patients, the (99m)Tc-HL91 image quality analysis classified seven cases into excellent, accounting for 21%, eight cases into good, for 24%, eight cases into fair, for 24%, and 10 cases into poor, for 31%. The ratios were 1.16 (1.01, 1.35) ((median (25th to 75th percentile)), 1.15, 0.20 and 1.01 (0.86, 1.30), respectively, in normal, ischaemic/viable and fixed defect myocardium. Significant differences (chi2=17.2069, P=0.0002) were found in the ratios. The ratios of the ischaemic/viable myocardial segments were significantly higher than those of the fixed defect segments. Unexpectedly, the normal myocardial segments took up (99m)Tc-HL91, too, even slightly higher than the ischaemic/viable myocardial segments.


CONCLUSIONS
Myocardial uptake of (99m)Tc-HL91 is perfusion-dependent as well as ischaemia dependent. (99m)Tc-HL91 hypoxia imaging alone is not sufficient to identify ischaemic/viable myocardium. Dual-isotope imaging with (201)Tl and (99m)Tc-HL91 can characterize the myocardium into normal, ischaemic/viable and necrotic (scarred) myocardium.
Yang
Xiang-Jun
XJ
Department of Cardiology, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China. yang_xiangjun@163.com
He
Yong-Ming
YM
Wu
Yi-Wei
YW
Zhang
Bin
B
Hui
Jie
J
Jiang
Ting-Bo
TB
Song
Jian-Ping
JP
Liu
Zhi-Hua
ZH
Jiang
Wen-Ping
WP
D000368:Aged; D015687:Cell Hypoxia; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D015609:Organotechnetium Compounds; D010091:Oximes; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013793:Thallium
D015609:Organotechnetium Compounds; D010091:Oximes; D019275:Radiopharmaceuticals; C105527:technetium Tc 99m 4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime; C027549:thallium chloride; D013793:Thallium