Journal Article

123I-Meta-Iodobenzylguanidine Scintigraphy in Sarcoidosis: Exploring Cardiac Autonomic Dysfunction in Patients with Unexplained Cardiac Symptoms

Raasing, Lisette R. M., van den Hoven, Andor F., Grutters, Jan C., Keijsers, Ruth G. M., Post, Marco C., Drent, Marjolein, Veltkamp, Marcel

2025

Overview

Background/Objectives: Sarcoidosis is a systemic inflammatory disease that can cause cardiac autonomic dysfunction (SCAD), often underrecognized despite its clinical importance. While [18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ([18F]FDG PET/CT) and cardiac magnetic resonance imaging (CMR) assess cardiac involvement, [123I]-meta-iodinebenzylguanidine ([123I]MIBG) scintigraphy evaluates cardiac sympathetic innervation, offering complementary insights to potentially improve SCAD detection and management. This retrospective study explores the role of [123I] MIBG scintigraphy in detecting SCAD among patients with unexplained cardiac symptoms. It focuses on its potential to provide complementary diagnostic information in patients where established imaging techniques, such as [18F]FDG PET/CT and CMR, fail to detect cardiac sarcoidosis. Methods: Sarcoidosis patients referred to the St. Antonius Hospital (2017–2024) who underwent [123I]MIBG scintigraphy were included. Collected data encompassed demographics, SCAD symptoms, cardiac imaging findings, and carvedilol treatment outcomes. [123I] MIBG abnormalities were defined as a heart-to-mediastinal ratio ≤1.6 or a washout rate ≥20%. Results: Among the final cohort of 40 sarcoidosis patients with unexplained cardiac symptoms and normal [18F]FDG PET/CT and CMR findings, 19 patients (48%) showed abnormal [123I] MIBG scintigraphy results suggestive of SCAD. No significant differences were observed in clinical characteristics between patients with normal and abnormal [123I]MIBG findings. Of the 16 patients treated with carvedilol, 88% reported symptom improvement, although 50% experienced side effects. Conclusions: [123I]MIBG scintigraphy revealed abnormalities in a substantial number of sarcoidosis patients with unexplained cardiac symptoms despite normal [18F]FDG PET/CT and CMR. These findings indicate a potential role for [123I]MIBG in detecting SCAD, but prospective studies are needed to confirm their clinical significance.

• Publisher: MDPI AG,Multidisciplinary Digital Publishing Institute (MDPI)
• Subject: autonomic dysfunction / Body mass index / Cardiac arrhythmia / cardiac disease / Heart / Magnetic resonance imaging / MIBG / Multidisciplinary teams / Patients / Reproducibility / Sarcoidosis / Scintigraphy / small fiber neuropathy / Tomography