INCREASED LUNG UPTAKE OF IODINE-123-MIBG IN DIABETICS WITH SYMPATHETIC NERVOUS DYSFUNCTION

Scintigraphy with I-123-MIBG and (TI)-T-201 was compared in patients w ith various diseases including diabetes mellitus, with and without sym pathetic nervous dysfunction. This study was done to assess lung uptak e of these tracers semiquantitatively Methods: Thirty-eight patients w ith diabetes mellitus, seven patients with dilated cardiomyopathy (DCM ), 12 patients with hypertrophic cardiomyopathy (HCM) and eight health y subjects were studied. Sympathetic nervous dysfunction was observed in 13 of the 38 diabetic patients. Simultaneous imaging with I-123-MIB G and (TI)-T-201 was performed, The ratio of lung to-total injected do se count and washout rate in the lung were calculated from dynamic ima ges acquired in the initial 2 min and static images acquired at 15 min and at 4 hr after injection of the tracers. Results: Lung uptake of I -123-MIBG at 4 hr was significantly increased in the diabetic group as compared with those in the other groups, In diabetic patients with sy mpathetic nervous dysfunction, the lung uptake ratio of I-123-MIBG at 4 hr was significantly higher than that in the diabetic patients witho ut sympathetic nervous dysfunction, due to decreased clearance of I-12 3-MIBG from the lung. On the other hand, increased lung uptake of (TI) -T-201 was observed in DCM patients at both 15 min and 4 hr. There was no significant difference between lung uptake of (TI)-T-201 in diabet ic patients and that in healthy subjects. Conclusion: Lung uptake of I -123-MIBG was increased and lung washout of I-123-MIBG was decreased i n diabetic patients with sympathetic nervous dysfunction, while lung u ptake of (TI)-T-201 was not altered, Iodine-123-MIBG scintigraphy of t he lung may provide information on sympathetic nervous activity in dia betic patients. It is a promising method for studying the kinetics of norepinephrine in the lung because MIBG is taken up in the lung by the same mechanism as norepinephrine.