Glucose-loading thallium-201 myocardial SPECT.
This study was designed to evaluate the feasibility of assessing myocardial viability using glucose loading followed by 201Tl SPECT.


METHODS
First, the effect of insulin on the kinetics of 201Tl uptake was evaluated in isolated perfused rat hearts. Second, glucose-loading 201Tl myocardial SPECT was performed in 13 nondiabetic patients with histories of anterior myocardial infarction. Thirty minutes before acquiring rest 201Tl SPECT, 20 g of glucose were intravenously injected into the fasting subjects. Thallium perfusion defects were compared to those of conventional rest-redistribution SPECT images obtained within a 2-wk interval. SPECT images were divided into 21 segments, and a defect score in 17 segments was calculated as a sum of the semiquantitative defect scores (0 = normal; 1 = mildly decreased uptake; 2 = severely decreased uptake; 3 = absence of uptake).


RESULTS
Thallium-201 uptake in isolated hearts showed a significant increase of 26% after insulin loading. Eleven (24%) of 45 segments showing perfusion defects on the conventional rest SPECT images demonstrated 201Tl uptake on glucose-loading SPECT imaging. Defect scores decreased significantly on the glucose-loading SPECT images (9.9 +/- 2.2 in early images; mean +/- s.e.) compared with the conventional rest-redistribution SPECT images (12.6 +/- 6.9 in delayed images, p < 0.05).


CONCLUSIONS
Glucose-loading SPECT represents a superior method for assessing myocardial viability using 201Tl.
Chiba
H
H
Department of Internal Medicine, Mimihara General Hospital, Sakai, Japan.
Kusuoka
H
H
Ohno
J
J
Nishimura
T
T
D000328:Adult; D000368:Aged; D000818:Animals; D005260:Female; D005947:Glucose; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D013794:Thallium Radioisotopes / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon
D007328:Insulin; D013794:Thallium Radioisotopes; D005947:Glucose