A Pilot Myocardial MIBG Scintigraphy Study in Prodromal and Overt Dementia with Lewy Bodies
Toji Miyagawa1, Cynthia Vernon1, Scott Przybelski1, Paul Min1, Julie Fields1, Leah Forsberg1, Erik St. Louis1, Kejal Kantarci1, Val Lowe1, Bradley Boeve1
1Mayo Clinic
Objective:
To establish the basis for a myocardial 123I-metaiodobenzylguanidine scintigraphy (MIBG-scintigraphy) study in the US and to assess its potential utility in prodromal dementia with Lewy bodies (DLB) clinical trials.
Background:
MIBG-scintigraphy noninvasively assesses postganglionic cardiac sympathetic denervation. Despite the internationally recognized importance of MIBG-scintigraphy in LBD, its use in LBD is not FDA approved and has rarely been used in the US for neurological research. We launched a pilot MIBG scintigraphy study in isolated REM sleep behavior disorder (iRBD) and mild cognitive impairment with Lewy bodies (MCI-LB) individuals, who are regarded as representing evolving LBD.
Design/Methods:
MIBG-scintigraphy was conducted in individuals with iRBD, MCI-LB, overt DLB, and healthy controls (HC). Heart-to-mediastinum (H/M) ratio of the MIBG uptake on delayed image (3-4 hours after Adreview® injection; late-HMR) was calculated with MIM workflow. Cutoff value of 2.2 was used for determining abnormal late-HMR. All participants were followed clinically and longitudinal scans were performed in selected participants.
Results:
MIBG-scintigraphy was conducted in 20 individuals (100% white, 80% male, mean age (yrs (SD) 69.9(7.9)). Eleven had iRBD (82% male, 68.7(7.3) yrs), three had MCI-LB (33% male, 70.0(8.5) yrs), three had DLB (100% male, 79.3(4.6) yrs), and three were HC (100% male, 64.7(2.4) yrs). Late-HMR (SD) and %abnormal late-HMR were 1.20(0.12) (100%) in DLB, 1.63(0.03) (67%) in MCI-LB, 2.45(0.19) (18%) in iRBD, and 2.77(0.14) (0%) in HC. No iRBD or MCI-LB participant developed DLB to date at follow-up visits. Three MCI-LB, three iRBD, and one HC had 2nd MIBG-scintigraphy. One MCI-LB participant became abnormal in the 2nd scan and the other participants had relatively unchanged findings.
Conclusions:
Our preliminary data suggest relatively lower abnormal MIBG-scintigraphy rate in iRBD participants which might be contributed to our iRBD cohort in earlier stage without apparent cognitive or motor impairment compared to the previously published reports.
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