The Feasibility Of Co-Registered Solid-State 123i-Mibg Spect And Ct Imaging For The Assessment Of Ventricular And Atrial Sympathetic Innervation In Healthy Individuals

Abstract Background. To evaluate global and regional ventricular and atrial cardiac iodine-123 meta-iodobenzylguanidine (123I-mIBG) uptake and consistency over time in healthy individuals using co-registered single-photon emission computed tomography (SPECT) and computed tomography (CT) imaging. Fifteen healthy individuals (median age 31 years [26; 41]) were included in the study. All participants underwent CT and subsequent baseline 123I -mIBG SPECT imaging (early and late acquisition) using a dedicated cardiac solid-state gamma camera. The heart-to-mediastinum (H/M) ratio, wash out rate (WR), summed 123I-mIBG defect score (SDS) as well as presence and patterns of left atrium (LA) discrete 123I-mIBG uptake areas (DUA) were assessed. Follow-up SPECT imaging was acquired 5–7 days after initial procedure.Results. At baseline median H/M ratio on the early and late acquisitions were 1.61 [1.57; 1.71] and 1.68 [1.65; 1.71] respectively, the WR was 22.5% [18.8; 22.8]. Areas of reduced 123I-mIBG uptake were detected in 60% (9/15) of cases and the median SDS was 1 [0; 2]. No significant changes were observed in global and regional 123I-mIBG cardiac uptake between baseline and follow-up studies. At baseline 36 DUA were identified, 16 (44%) of which (median per individual 1 [1;1]) had moderate-high confidence score (CS). 5/16, 4/16, 4/16 and 3/16 moderate-high CS DUAs were located around the left sided-, right sided pulmonary veins ostia, LA walls or right atrium (RA) respectively. At follow-up 33 DUAs were identified, 16 (48%) of which (median per individual 1 [1;1], p = 0.5 vs baseline) had moderate-high CS. Moderate-high CS discrete uptake areas had generally the same location as on the baseline procedure.Conclusion. Co-registered solid-state 123I-mIBG SPECT and CT is feasible for the evaluation of left ventricle sympathetic innervation as well as for the detection of discrete sympathetic areas in the typical anatomical sites of left atrial ganglionated plexi with modest variations in the constancy of uptake locations. There were no significant changes in the global and regional 123I-mIBG left ventricular uptake over a short time interval in healthy individuals.