Effect of exercise-induced activation of sympathetic nerve activity on clearance of 123I-MIBG from the myocardium.
The effect of exercise on the cardiac kinetics of 123I-MIBG was investigated in the present study. 123I-MIBG was administered intravenously at rest in 6 healthy male volunteers, and anterior planar and SPECT images were obtained 15 minutes, and 2 and 4 hours after administration (protocol A). After 4 weeks, 123I-MIBG was again administered intravenously at rest, and images were obtained 15 minutes later. After imaging, the subjects ran 10 km in approximately 1 hour, and anterior planar and SPECT images were obtained 2 and 4 hours after administration of 123I-MIBG (protocol B). The heart-to-mediastinum uptake ratio (H/M) was calculated from each anterior planar image, and the mean 123I-MIBG clearance from 15 minutes to 2 hours, and from 2 hours to 4 hours was calculated with a bull's eye display. The H/M was much lower after exercise. The mean clearance rate between 15 minutes and 2 hours in protocol B was significantly higher than that between 2 hours and 4 hours, and that between 15 minutes and 2 hours in protocol A. It was concluded that the clearance rate of 123I-MIBG may be a useful index of cardiac sympathetic nerve activity.
Sugihara
H
H
Department of Radiology, Kyoto Prefectural University of Medicine, Japan.
Shiga
K
K
Terada
K
K
Kinoshita
N
N
Taniguchi
Y
Y
Ito
K
K
Adachi
Y
Y
Ushijima
Y
Y
Nakagawa
M
M
Maeda
T
T
D019797:3-Iodobenzylguanidine / Q000378:metabolism* / Q000493:pharmacokinetics; D000328:Adult; D015444:Exercise / Q000502:physiology*; D006321:Heart / Q000000981:diagnostic imaging* / Q000294:innervation; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000378:metabolism* / Q000493:pharmacokinetics; D013564:Sympathetic Nervous System / Q000502:physiology*
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine