123I-MIBG myocardial scintigraphy in diabetic patients. Relationship with 201Tl uptake and cardiac autonomic function

The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by 201Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after 123I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of 123I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the 201Tl image and the 123I-MIBG image in the total uptake score (TUS) was taken as the difference in the total uptake score (ΔTUS) representing cardiac sympathetic denervation without SMD. On both early and delayed planar images, the mean H/M value in the subgroups of diabetic patients was significantly lower in the SMD (+) AN (+) group than in the control group, but among those subgroups, there was statistically significant difference between the SMD (+) AN (+) and SMD (-) AN (-) groups only on the delayed images. Regarding the WR value, there was no statistically significant difference among subjects. On SPECT image analysis, the diabetic subgroup with AN or SMD had statistically significant lower values for TUS than those of the control group. Among diabetics, there was a statistically significant differences between SMD [+] AN [+] and SMD [-] AN [-] on both early and delayed images. Similarly, the SMD [+] AN [-] group also had significantly lower values than those of SMD [-] AN [-] on early images. Regarding ΔTUS, there was a statistically significant differences between AN [+] subgroups and controls. Similarly, the mean value for ΔTUS was much higher in AN [+] subgroups than in AN [-] subgroups with or without SMD in diabetes mellitus. (K.H.)