Impact of age on myocardial uptake of 123I-mIBG in older adult subjects without coronary heart disease

Abstract

BackgroundThe purpose of this study was to examine the relationship between myocardial uptake of 123I-mIBG and age in older normal adult subjects. Methods94 subjects (age 29-82, mean 58.5) without coronary heart disease were studied. All subjects underwent early and delayed planar and 4-hour SPECT 123I-mIBG imaging. 123I-mIBG uptake was quantified as heart/mediastinum ratio on planar images (H/Mp) and on SPECT images (H/Ms) reconstructed by filtered backprojection, ordered subsets-expectation maximization (OSEM), and OSEM with compensation for collimator septal penetration (DSP). Relationships between age and 123I-mIBG uptake were examined by correlation analysis, t-tests, and analysis of variance. ResultsThere was no significant correlation between age and H/Mp, reflecting comparable increases in activity in the two regions of interest with age. Results on SPECT analyses were comparable, with no significant correlation between age and H/Ms. Using DSP, 123I-mIBG H/Ms was significantly higher in subjects ≥70 of age compared with younger subjects. ConclusionsBoth cardiac and background uptake of 123I-mIBG increase with age in older subjects without coronary heart disease, resulting in stability of H/M results (planar and SPECT). This study suggests that prognostic analyses of quantitative 123I-mIBG uptake in patients with heart disease do not require adjustment for patient age.