Background Global iodine-123 metaiodobenzylguanidine (123I-MIBG) uptake is predictive of cardiovascular events and mortality in patients with heart failure. Normal variations in global and regional uptake, however, are not well defined and few studies have addressed the functional relevance of 123I-MIBG uptake and distribution in healthy individuals. Materials and methods We performed 123I-MIBG scintigraphy and cardiac autonomic function testing using the standardized methodology in 15 healthy individuals (mean age 54.6± 5.3 years, male : female 10 : 5) with no evidence of previous myocardial infarction or ischaemic heart disease. Results Early heart to mediastinum ratio (HMR) was 1.67± 0.13, late HMR was 1.73 ± 0.16 and washout rate was 19.09 ± 7.63% (4.20-31.30). Regional analysis showed reduced tracer uptake at the apex, base and inferior wall in all individuals. Early and late HMR correlated negatively with RFa (r=-0.603; P=0.05 and r=-0.644; P=0.033) and expiration and inspiration ratio (r=-0.616; P=0.043 and r=-0.676; P=0.022) and positively with LFa/RFa (r=0.711; P=0.014 and r=0.784; P=0.004). Washout rate correlated only with RFa (r=0.642; P=0.033). Conclusion Healthy adults show a heterogeneous pattern of cardiac innervation with reduced regional uptake of 123I-MIBG. Furthermore, HMR correlates with indices of cardiac sympathetic function, suggesting that it might not only be a useful prognostic marker but may also provide insight into the functional integrity of the cardiac autonomic nervous system.
- Cardiac autonomic neuropathy
- Cardiac innervation
- Iodine-123 metaiodobenzylguanidine
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging