Background: The use of 123I-mIBG has been approved for decades for Parkinson’s disease
(PD) diagnosis and as a predictor of mortality and potentially fatal events in patients with Heart Failure
(HF). The standardized technique includes an early acquisition (15 minutes from injection), and a late
acquisition (240 minutes). Early images mainly represent interstitial uptake, whereas delayed images
represent actual neuronal uptake, however, it is reasonable to affirm that different pathological situations,
such as PD and HF, imply a different meaning for early and late imaging.
Objective: This prospective study aims to investigate the clinical usefulness of an immediate planar
123I-mIBG image acquisition (5 minutes) both in patients with PD and in patients with HF.
Methods: 115 patients referred to 123I-mIBG cardiac imaging in Nuclear Medicine Center have been
enrolled (60 patients with PD, absence of diabetes and/or cardiologic pathology, Hoehn e Yahr classification
≤ 1.5; 55 patients with cardiomyopathy, diagnosis of HF, NYHA class I–III). 123I-mIBG planar
anterior thoracic acquisitions were performed after 5 (immediate), 15 (early) and 240 (late) minutes
from injection and H/M ratios were calculated.
Results: In PD group H/M mean values resulted in 1.58±0.22 for immediate (5 min), 1.61±0.26 for
early (15 min) and 1.59±0.37 for late (240 min) acquisitions. In the HF group, H/M mean values resulted
in 1.63±0.24 for immediate (5 min), 1.65±0.22 for early (15 min) and 1.57±0.17 for late (240
min) acquisitions, respectively. H/M values obtained at 5 min and 15 min are provided similar results,
with no statistical difference (p = ns) regardless of the pathology examined (PD or HF groups). The
statistical analyses validated the diagnostic role of immediate acquisition (5 min) and early acquisition
(15 min) in PD group as compared to the standardized late acquisition (240 min). On the contrary, in
HF group, immediate and early acquisition, as compared to late acquisition (240 min), is not validated
as a major cardiac events predictor.
Conclusion: Our results indicate the potential role of immediate (5 min) or early (15 min) acquisition
in replacement of standardized 240 minutes acquisition in PD patients, but this result is not confirmed
in HF patients, in which the acquisition at 240 min is confirmed as the most affordable timing for image
interpretation, emphasizing the different pathophysiology that underlies these two pathologies.