Hybrid solid-state SPECT/CT left atrial innervation imaging for identification of left atrial ganglionated plexi: Technique and validation in patients with atrial fibrillation

Co-Registered Solid-State 123i-Mibg Spect And Ct Imaging For The Assessment Of Sympathetic Cardiac Innervation In Healthy Individuals And Variation Over Time

“…Originally developed as a radionuclide for imaging adrenal tumors, 123 I-mIBG has emerged as a promising tool for the prediction of heart failure progression [16], arrhythmic events [17], and even prognosis of AF recurrence after interventional treatment [18]. More recently, imaging with dedicated cardiac SPECT cameras using solid-state CZT detectors has been shown to identify discrete areas of sympathetic activity that correlate with GPs identified invasively using high frequency stimulation (HFS) [10].…”

“…Several studies have assessed the comparative performance of Anger-type and CZT SPECT systems for detection of left ventricular myocardial tracers [7][8][9], but there are few studies evaluating left atrial 123 I-mIBG uptake using CZT systems, particularly in healthy individuals. In patients with atrial fibrillation, 123 I-mIBG CZT SPECT co-registered with cardiac CT has been reported to identify discrete 123 I-mIBG uptake areas (DUAs) non-invasively that correlate with left atrial ganglionated plexi (LAGP) identified invasively by high-frequency stimulation (HFS) during pulmonary vein isolation (PVI) catheter ablation [10]. However, imaging patterns of LAGP in healthy individuals have never been demonstrated.…”

I-123-MIBG cardiac innervation imaging in patients with atrial fibrillation

“…19 In this issue of the Journal, Stirrup et al have addressed the usefulness of cardiac MIBG scintigraphy for non-invasive identification of LA GPs. 20 It would be of clinical importance for the ablation of the plexi, as a potential add-on to PVI in patients with PAF, if MIBG SPECT could replace invasive HFS technique with its well recognized limitations for GPS identification. The idea behind the presented method is that localization of GPs by invasive multi-site testing HFS, a process that identifies GPs by their typical parasympathetic response of slowing atrio-ventricular nodal conduction, and noninvasive imaging of LA sympathetic innervation by MIBG, might identify the same areas, as sympathetic and parasympathetic fibers co-localize in GPs.…”

“…However, DUAs identified over the lateral and inferior LA walls were less likely to be HFS positive, probably due to difficulty in distinguishing true LA epicardial activity from activities in neighboring structures. 20 The usefulness of ablation of autonomic ganglia as an initial or repeat ablation strategy for AF is not well established, as the results of randomized studies are not unequivocal. Further studies are needed to better understand the role of GPs ablation for rhythm control.…”

“…It should be stressed that the presented methodology is developed for a specific scintigraphic system with a dedicated application software for the fusion of D-SPECT scintigraphic images with CT scans and with electrophysiological signals, and for the identification of discreet uptake areas of MIBG. 20 The natural alternative for MIBG-CZT-SPECT-CT technique could be PET-CT. Taking into account its high sensitivity, spatial resolution, existing advanced software for reconstruction and fusion, proved ability to image small uptake areas within heart (for example, for identification of high-risk atherosclerotic plaques in coronary arteries 21 ), and advanced development of new F-18 labeled tracers of cardiac innervation, 22 PET-CT has a high potential to apply to atrial diagnostics.…”