Washout rate of 123I-metaiodobenzylguanidine increased by posture change or exercise in normal volunteers.
123I-metaiodobenzylguanidine (MIBG) imaging detects sympathetic nerve function in the heart. The present study was conducted to clarify whether posture change or exercise affects 123I-MIBG kinetics in normal volunteers. Seven subjects underwent three 123I-MIBG studies, i.e., supine protocol, sitting protocol and exercise protocol. Planar 123I-MIBG images were obtained at 15 minutes, 1 hour and 4 hours after injection of 123I-MIBG. The washout rate (WR) from 15 minutes to 1 hour in the supine position in all subjects was similar for all three protocols, whereas the WR from 1 hour to 4 hours was significantly augmented in the sitting protocol and the exercise protocol as compared to the supine protocol (p < 0.05 and p < 0.01). The serum concentration of noradrenaline was significantly increased from the baseline to the 4 hour sampling in the sitting protocol and the exercise protocol (both p < 0.01), but was not altered in the supine protocol. The WR from 1 hour to 4 hours significantly correlated with the noradrenaline concentration in 4 hour sampling (r = 0.59, p < 0.01). It also significantly correlated with an increase in the noradrenaline concentration from the baseline to the 4 hour sampling (r = 0.53, p < 0.05). It is concluded that posture change or exercise affects the WR of 123I-MIBG in normal healthy subjects.
Yano
T
T
First Department of Internal Medicine, Kobe University School of Medicine, Japan.
Yamabe
H
H
Yokoyama
M
M
D019797:3-Iodobenzylguanidine / Q000493:pharmacokinetics*; D000328:Adult; D006321:Heart / Q000000981:diagnostic imaging* / Q000294:innervation; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000097:blood; D005082:Physical Exertion; D011187:Posture; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D016683:Supine Position; D013564:Sympathetic Nervous System / Q000502:physiology
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D009638:Norepinephrine