Significance of increased lung thallium-201 activity on serial cardiac images after dipyridamole treatment in coronary heart disease.
Increased lung thallium-201 (Tl-201) activity occurs in patients with severe coronary artery disease (CAD) on initial postexercise images. To determine the significance of assessing lung Tl-201 on serial imaging after dipyridamole therapy, initial and delayed (2 to 3 hours) Tl-201 imaging was performed in 40 patients with CAD and 26 normal control subjects. Lung Tl-201 activity was quantitated as a percentage of maximal myocardial activity for each imaging time (lung Tl-201 index). The mean initial lung Tl-201 activity was 42 +/- 2% (+/- standard error of the mean) in 26 control subjects, 56 +/- 2% in 25 patients with 2- or 3-vessel CAD (p less than 0.001) and 53 +/- 2% in 15 patients with 1-vessel CAD (p less than 0.005 compared with control subjects) (difference not significant between 1-vessel and multivessel CAD). Dipyridamole lung Tl-201 activity decreased relative to the myocardium from initial to delayed images (p less than 0.001) in patients with CAD but not in control subjects. When a dipyridamole lung Tl-201 index of 58% (mean +/- 2 standard deviations for control subjects) was chosen as the upper limit of normal, 14 of 40 of the CAD patients (35%) had abnormal values and all control patients had values within normal limits. These 14 patients with CAD and abnormal initial lung Tl-201 indexes had rest ejection fractions that were not significantly different from those in patients with CAD, and normal initial dipyridamole lung Tl-201 index (58 +/- 4% and 63 +/- 2%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
D000328:Adult; D000368:Aged; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy; D004176:Dipyridamole; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011433:Propranolol / Q000627:therapeutic use; D011868:Radioisotopes; D011877:Radionuclide Imaging; D013318:Stroke Volume; D013793:Thallium
D011868:Radioisotopes; D004176:Dipyridamole; D011433:Propranolol; D013793:Thallium