Hybrid Magnetic Resonance Positron Emission Tomography Is Associated With Cardiac-Related Outcomes in Cardiac Sarcoidosis.

Background: Imaging with late gadolinium enhancement (LGE) magnetic resonance (MR) and ¹⁸ F-fluorodeoxyglucose ( ¹⁸ F-FDG) PET allows complementary assessment of myocardial injury and disease activity and has shown promise for improved characterization of active cardiac sarcoidosis (CS) based on the combined positive imaging outcome, MR(+)PET(+).
Objectives: This study aims to evaluate qualitative and quantitative assessments of hybrid MR/PET imaging in CS and to evaluate its association with cardiac-related outcomes.
Methods: A total of 148 patients with suspected CS underwent hybrid MR/PET imaging. Patients were classified based on the presence/absence of LGE (MR+/MR-), presence/absence of ¹⁸ F-FDG (PET+/PET-), and pattern of ¹⁸ F-FDG uptake (focal/diffuse) into the following categories: MR(+)PET(+) _FOCAL , MR(+)PET(+) _DIFFUSE , MR(+)PET(-), MR(-)PET(+) _FOCAL , MR(-)PET(+) _DIFFUSE , MR(-)PET(-). Further analysis classified MR positivity based on %LGE exceeding 5.7% as MR(+/-) _5.7% . Quantitative values of standard uptake value, target-to-background ratio, target-to-normal-myocardium ratio (TNMRmax), and T2 were measured. The primary clinical endpoint was met by the occurrence of cardiac arrest, ventricular tachycardia, or secondary prevention implantable cardioverter-defibrillator (ICD) before the end of the study. The secondary endpoint was met by any of the primary endpoint criteria plus heart failure or heart block. MR/PET imaging results were compared between those meeting or not meeting the clinical endpoints.
Results: Patients designated MR(+) _5.7% PET(+) _FOCAL had increased odds of meeting the primary clinical endpoint compared to those with all other imaging classifications (unadjusted OR: 9.2 [95% CI: 3.0-28.7]; P = 0.0001), which was higher than the odds based on MR or PET alone. TNMRmax achieved an area under the receiver-operating characteristic curve of 0.90 for separating MR(+)PET(+) _FOCAL from non-MR(+)PET(+) _FOCAL , and 0.77 for separating those reaching the clinical endpoint from those not reaching the clinical endpoint.
Conclusions: Hybrid MR/PET image-based classification of CS was statistically associated with clinical outcomes in CS. TNMRmax had modest sensitivity and specificity for quantifying the imaging-based classification MR(+)PET(+) _FOCAL and was associated with outcomes. Use of combined MR and PET image-based classification may have use in prognostication and treatment management in CS.
Competing Interests: Funding Support and Author Disclosures This work was supported by National Institutes of Health (NIH) grant R01 HL071021 (ZAF), NIH grant KL2 TR001435 (MGT), and AHA grant 20CDA35310099 (MGT). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2024. Published by Elsevier Inc.)