Evaluation of CZT SPECT imaging for cardiac sympathetic innervation in healthy individuals and patients with atrial fibrillation

Abstract

Background ― Cadmium zinc telluride (CZT) solid-state detectors have been recently introduced in the field of nuclear medicine in cardiology. The aim of the current study was to investigate the scintigraphic patterns of total uptake and the regional distribution of iodine-123 metaiodobenzylguanidine (123I-mIBG) in healthy volunteers and patients with atrial fibrillation (AF) using a gamma camera equipped CZT detectors. Material and Methods ― The total number of included subjects was 30 (15 patients with a paroxysmal form of AF and 15 healthy volunteers). Using a novel single-photon emission computed tomography (SPECT) cardiac dedicated gamma camera equipped CZT-detectors the scintigraphy was performed 15 minutes and 4 hours after intravenous administration of norepinephrine structural analogue 123I-mIBG. Thus, data from early and delayed phases were obtained. The heart-to-mediastinum ratio of 123I-mIBG uptake at 15 minutes (HMRe) and 4 hours (HMRd), as well as the washout rate (WR) and summed 123I-mIBG score (SMSe, SMSd) were measured. Results ― Patients and volunteers showed comparable results of the median ratio of 123I-mIBG uptake in the heart and mediastinum (HMR) in the early and delayed phases (p>0.05). In 14 (93%) patients with AF, 123I-mIBG uptake defects in LV myocardium were detected as compared with 8 (53%) healthy individuals (p<0.05). The healthy volunteers showed no significant 123I-mIBG uptake defect in delayed scans compared with a median result in patients with AF (p<0.001). Conclusion ― SPECT gamma camera with CZT-detectors is suitable to obtain qualitative tomographic slices of the myocardium and to assess regional changes in sympathetic innervation of the heart, which can be the early signs of an imbalance in the autonomic nervous system. Therefore, this camera may be useful for managing patients with various forms of AF.