Comparison between reference values for 201thallium uptake and washout from the myocardium after exercise and after dipyridamole.
A slow washout of 201Thallium has a high diagnostic and prognostic value for coronary artery disease. The aim of the present work was to contribute with reference data on 201Tl uptake and washout from the myocardium. With a quantitative method using circumferential profiles and interpolative background subtraction we performed 201Tl myocardial imaging in two groups of subjects with a low probability of coronary artery disease. Washout in per cent is defined as (1-D/I).100, where D is the delayed uptake rate and I the initial uptake rate. In group A (n = 16) myocardial hyperaemia was induced by maximal exercise, in group B (n = 15) by intravenous infusion of dipyridamole. In group A, the mean washout was 52%, and in group B it was 34% (P < 0.001). The delayed uptake rate D was significantly higher after dipyridamole, 58.4 cps, than after exercise, 44.5 cps (P < 0.05). There was no significant differences in I between the two groups. The findings regarding D and I explain that the washout is slower after dipyridamole than after exercise, as the mean D/I ratio was 0.48 in group A and 0.66 in group B (P < 0.001).
Munck
O
O
Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, University of Copenhagen, Denmark.
Madsen
P V
PV
Kelbaek
H
H
Godtfredsen
J
J
D000328:Adult; D000368:Aged; D004176:Dipyridamole; D005080:Exercise Test; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D011877:Radionuclide Imaging; D012016:Reference Values; D013794:Thallium Radioisotopes / Q000378:metabolism*
D013794:Thallium Radioisotopes; D004176:Dipyridamole