Imaging of Inflammation in Unexplained Cardiomyopathy

Abstract

Myocarditis is a recognized but underdiagnosed cause of cardiomyopathy due to its wide clinical spectrum and nonspecific presentation. Accurate diagnosis is important because 25% of patients with acute myocarditis develop cardiomyopathy, and of those, approximately 5% per year require heart transplantation or die. Current guidelines for the recognition and treatment of the inflammatory cardiomyopathies are limited. The gold standard for diagnosis, endomyocardial biopsy, has low sensitivity, and thus, multimodality imaging of inflammation plays a crucial role in defining the cardiac abnormalities and in assisting with diagnosis and management. The literature on inflammatory cardiomyopathies is limited to small studies of selected populations due to the diverse etiologies and inherent difficulties in definitive diagnosis. This review focuses on the current and projected use of various imaging modalities, including echocardiography, cardiac magnetic resonance, and nuclear imaging to better define inflammatory cardiomyopathies and aid in their management; it specifically focuses on cardiac sarcoidosis, and giant cell, eosinophilic, and lymphocytic myocarditis.

Cardiac Magnetic Resonance Imaging in Myocarditis Reveals Persistent Disease Activity Despite Normalization of Cardiac Enzymes and Inflammatory Parameters at 3-Month Follow-Up

“…16 Recently, CMR has evolved as the gold standard for noninvasive testing. [25][26][27][28] Quantification of LGE can represent a wide variety of tissue processes and has emerged as a diagnostic tool in ischemic heart disease to measure areas of infarction 29 and for risk stratification in ischemic 30,31 and nonischemic heart disease. [32][33][34] Although in clinical practice decreasing cardiac enzymes and inflammatory markers are commonly interpreted as being indicative of resolving myocarditis, no cardiac imaging studies have confirmed this assumption as of today.…”

Diagnosis and Therapy of Cardiac Sarcoidosis: A Clinical Perspective

“…Vita et al used an imaging rubric combining cardiac PET and MRI findings based on specific imaging characteristics to develop the likelihood criteria for the diagnosis of CS. 27 They then compared these findings to a pre-specified reference criteria based on clinical data and consensus statement recommendations. Combination imaging helped reclassify 48 (45%) of the patients into higher or lower probabibility categories, most of them (80%) being correctly re-classified when compared with final diagnosis.…”

Cardiac Involvement in Sarcoidosis: Evolving Concepts in Diagnosis and Treatment

“…The earlier studies are useful primarily for historical interest. Currently, 18F-fluorodeoxyglucose ( 18 FDG) 86 and gadolinium-enhanced cardiac MRI (CMR) scans 87,[117][118][119] have supplanted other radionuclide scans to diagnose cardiac sarcoidosis.…”

“…PET/CT with 18 FDG is a key technique to diagnose active cardiac sarcoidosis 88,[119][120][121][122][123][124][125] (►Figs. 2--6).…”