Seeing Beyond the Obvious

Sarcoidosis is a systemic inflammatory disease characterized by the deposition of noncaseating granulomas in multiple organs, including the lungs, skin, central nervous system, and heart.1 The diagnosis of cardiac sarcoidosis is important because it confers a poorer prognosis, with an increased risk of ventricular arrhythmias, heart failure, and sudden cardiac death.1 The early detection of cardiac involvement in sarcoidosis may provide an opportunity for early intervention using immunosuppressive therapies, and identification of high-risk patients may warrant device therapy using implantable cardioverter defibrillator to prevent sudden cardiac death.See Article by Greulich et al The detection of cardiac sarcoidosis can be challenging using conventional modalities such as echocardiography because of the fact that areas of granulomatous deposition, inflammation, and fibrosis may not always be obvious when assessing for regional or global systolic function.18 Fluorodeoxyglucose positron emission tomography can noninvasively detect the associated myocardial inflammation, albeit with lower spatial resolution than cardiovascular magnetic resonance (CMR) imaging.2 CMR offers high spatial resolution for cardiac function and superior tissue characterization. In cardiac sarcoidosis, late gadolinium enhancement (LGE) correlates to areas of dense fibrosis and granulomatous inflammation within patchy fibrosis3 and carries a poor prognosis for all-cause mortality and future arrhythmogenic events.1 Myocardial inflammation may be evident on early-gadolinium enhancement and T2-weighted imaging.4,5 Fusion imaging of18 fluorodeoxyglucose positron emission tomography and magnetic resonance imaging may have a role in the characterization of cardiac sarcoidosis.2The underlying magnetic resonance physics principles for novel CMR mapping techniques are discussed elsewhere.6 The basic principle for clinical applications is that each tissue type has a normal range of T1, T2, and extracellular volume (ECV) values, deviation from which may indicate disease or a change in physiology. Parametric maps are quantitative, and within a chosen method, can be …