123I-MIBG lung uptake in patients with diabetes mellitus

The purpose of this study is to clarify the relationship between 123I-MIBG lung uptake and silent myocardial ischemia (SMI), cardiac autonomic neuropathy (AN) or clinical characteristics. For the quantitative analysis, lung to upper mediastinum uptake ratio (L/M) and heart to upper mediastinum uptake ratio (H/M) were obtained from chest planar image. In addition, both lung washout ratio (%WR-L) and heart washout ratio (%WR-H) were calculated from early and delayed images. Each indices were compared in both diabetic and control groups. Mean values of H/M in diabetes with complication were significantly lower than those of control group. Particularly, AN(+)SMI(+) group showed lowest value. Similarly, mean values of %WR-H in diabetes with complication were significantly higher than those of control group and AN(+)SMI(+) group showed highest value. Although mean value of L/M in each diabetic group was significantly higher than that of control group, there was no statistical significance among each diabetes except AN(+)SMI(-) group on early image. Mean value of %WR-L in AN(+) or SMI(+) group was also significantly higher than that of control group, but there was no statistical significance among each diabetic group. The current study suggested that high pulmonary 123I-MIBG uptake in diabetes was independent of the complication of SMI or AN. Pulmonary endothelial dysfunction related with severity of diabetes mellitus was considered to be the most important factor. (author)