ABSTRACT
Introduction
Cardiac sarcoidosis (CS) is the cardiac, and occasionally the only manifestation, of a systemic disease of unknown etiology inherently challenging to definitively diagnose due to the lack of a reliable gold standard, the current being endomyocardial biopsy, the yield of which is low owing to the patchy nature of involvement. Societal guidelines employ specific criteria to make a probabilistic diagnosis, integrating clinical assessment with conventional and advanced cardiac imaging.
Areas covered
This review begins with an introduction to CS, followed by a discussion of diagnostic guidelines commonly used, then delves into an in-depth review of the imaging modalities currently available to assess for CS. Particular attention is made to discussing findings, strengths, limitations, and future directions for each modality.
Expert opinion
The burden of CS may be significantly larger than previously thought. With the low yield of endomyocardial biopsy, advanced cardiac imaging is increasingly employed to determine CS likelihood. Cardiac magnetic resonance is adept at detecting myocardial scar and able to differentiate between CS and other cardiomyopathies. F-18 Fluorodeoxyglucose positron emission tomography is superior at detecting active disease (myocardial inflammation) which may be amenable to immunosuppressive treatment, as well as detecting extracardiac involvement and identifying potential biopsy sites.
Article highlights
The incidence of cardiac sarcoidosis (CS) is on the rise, either due to improved detection, truly increased disease incidence, or both.
Definitive diagnosis requires tissue evidence, but the patchy nature of myocardial involvement renders the yield of an endomyocardial biopsy low.
The two main societal guidelines: the Heart Rhythm Society and the Japanese Circulation Society utilize criteria to make a probabilistic diagnosis.
Patients with systemic sarcoidosis should be screened by clinical history/examination and electrocardiography.
Advanced cardiac imaging with cardiac magnetic resonance (CMR) and/or F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) is valuable for CS detection in patients with extracardiac sarcoidosis with test findings or clinical picture suggestive of isolated CS.
CMR is useful for detecting myocardial scar and for differentiation between CS and other cardiomyopathies, while FDG PET is useful for detecting and following up disease activity and extracardiac involvement.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Reviewer disclosures
Peer reviewers in this manuscript have no relevant financial or other relationships to disclose.
List of abbreviations
ASNC | = | American Society of Nuclear Cardiology |
AV | = | Atrioventricular |
BBB | = | Bundle branch block |
CAD | = | Coronary artery disease |
CMR | = | Cardiac Magnetic Resonance |
CS | = | Cardiac Sarcoidosis |
CT | = | Computed Tomography |
DNA | = | Deoxyribonucleic Acid |
ECG | = | Electrocardiogram |
EMB | = | Endomyocardial Biopsy |
FDG | = | Fluorodeoxyglucose |
FLT | = | Fluorothymidine |
FWHM | = | Full width at half maximum |
GLS | = | Global Longitudinal Strain |
HFLC | = | High-Fat-Low-Carbohydrate |
HRS | = | Heart Rhythm Society |
JCS | = | Japanese Circulation Society |
JMHW | = | Japanese Ministry of Health And Welfare |
LGE | = | Late Gadolinium Enhancement |
LV | = | Left Ventricle |
LVEF | = | Left Ventricular Ejection Fraction |
MBF | = | Myocardial Blood Flow |
MFR | = | Myocardial flow reserve |
MPI | = | Myocardial perfusion imaging |
MR | = | Magnetic resonance |
MRI | = | Magnetic Resonance Imaging |
PET | = | Positron Emission Tomography |
PVC | = | Premature Ventricular Contraction |
ROI | = | Region of interest |
RV | = | Right ventricle |
RWMA | = | Regional wall motion abnormalities |
SCD | = | Sudden cardiac death |
SNMMI | = | Society of Nuclear Medicine and Molecular Imaging |
SPECT | = | Single photon emission computed tomography |
SUV | = | Standardized uptake value |
tCMA | = | Total cardiac metabolic activity |
VF | = | Ventricular fibrillation |
VT | = | Ventricular tachycardia |