Dobutamine combined with low-level exercise for myocardial perfusion scintigraphy

Increased abdominal background activity is one of the limitations of dobutamine myocardial perfusion scintigraphy which may interfere with interpretation of the images. In this study, we evaluated the value of low-level exercise supplementation to dobutamine infusion in improving image quality. The control group (n = 32, Group A) received dobutamine alone, while the study group received dobutamine plus low-level exercise for the last 2 min of dobutamine administration (n = 26, Group B). One hundred and eleven MBq of 201Tl was injected 1 min before cessation of peak dose. The ratios of cardiac/hepatic (C/HEP), cardiac/subdiaphragmatic (C/INF) and cardiac/pulmonary (C/PUL) were calculated from anterior planar images taken immediately following the test. Cardiac/non-cardiac activity was also visually graded on a three-point scale. Visual evaluation showed improved cardiac/non-cardiac ratios as confirmed by significantly higher C/HEP and C/INF ratios for Group B (1.5+/-0.3 and 1.7+/-0.2, respectively) compared to corresponding values in Group A (1.2+/-0.4 and 1.4+/-0.4, respectively) (P<0.05). The cardiac/pulmonary (C/PUL) ratio was also higher for Group B (2.3+/-0.5) as compared to corresponding value in Group A (2.0+/-0.6, respectively), but this difference did not reach statistical significance (P > 0.05). No difference in the frequency of side effects and ECG changes were detected between the two groups (P > 0.05). Low-level exercise supplementation to dobutamine infusion for myocardial perfusion scintigraphy is a safe method and leads to a significant decrease in uptake by the areas adjacent to the heart, improving image quality.