Cardiac sarcoidosis (ECR 2016 Case of the Day)

Clinical History

A 33-year-old male patient presented with syncopal episode.

Imaging Findings

Fig. 1a: Axial CT thorax in lung windows demonstrates peribronchovascular nodularity in the right upper lobe.
Fig. 1b: Axial CT of the thorax post contrast in soft tissue windows demonstrating paratracheal and subcarinal adenopathy.
Fig. 2: Serial T1 weighted basal to apical short axis slices from the base to apex of the left ventricle acquired ten minutes following a weight-based dose of intravenous gadolinium demonstrating diffuse subepicardial myocardial delayed enhancement predominantly involving the interventricular septum.

Discussion

Cardiac involvement is one of the most devastating and unpredictable aspects of sarcoidosis and is seen in approximately 2-5% of affected patients [1]. Previously, most cardiac deaths from sarcoidosis were due to a fatal arrhythmia, however, the growing use of implantable defibrillators and pacemakers has made progressive heart failure a more frequent cause.

Complete AV block is the most commonly seen arrhythmia affecting 23-30% of patients with clinically evident cardiac disease, partially explained by a propensity for the disease to affect the basal portion of the interventricular septum and areas in the vicinity of the conduction system [2, 3]. Less commonly, sarcoidosis can lead to structural and mechanical abnormalities, including valvular dysfunction, pulmonary hypertension, ventricular aneurysms and, eventually, congestive cardiac failure [4].

Sarcoidosis is often an incidental finding on a chest radiograph, classically showing bilateral hilar and right paratracheal lymph node enlargement, with or without pulmonary parenchymal involvement. Serum calcium is elevated in 10% of patients with sarcoidosis and can provide a further diagnostic clue [5]. Serum ACE levels are of limited value but are often used for monitoring a response to treatment [6].

Electrical monitoring (ECG or Holter monitoring) and echocardiography are used initially in patients in whom cardiac disease is suspected. Advanced imaging studies such as MRI and PET/CT are also useful for detecting asymptomatic cardiac involvement but have the added advantage of assessing disease activity. MRI is the modality of choice for evaluating the myocardium in both ischaemic and non-ischaemic cardiomyopathies, including sarcoidosis [7]. Cardiac MR accurately identifies areas of myocardial thinning and regional wall motion abnormalities on cine images. The septum and lateral walls are the most frequently involved [8]. Late gadolinium enhancement is an indicator of myocardial fibrosis and can identify areas of granulomatous infiltration, which typically affect the epicardium and the mid-portion of the myocardium [9].

CT is the primary technique for demonstrating pulmonary sarcoidosis but ECG-gated cardiac CT may also be useful for demonstrating cardiac involvement in patients with cardiac devices that cannot undergo MRI, however, the development of MR conditional devices will likely see this limitation overcome [10].

Recent experience with PET/CT has led to significant improvements in the management of patients with known or suspected cardiac involvement. Cardiac inflammation shows up as high signal in the myocardium and quantification of FDG-activity not only assists in assessing disease activity, but is also of prognostic value [11, 12].

Differential Diagnosis List

Final Diagnosis

Cardiac Sarcoidosis

URL:	https://www.eurorad.org/case/13716
DOI:	10.1594/EURORAD/CASE.13716
ISSN:	1563-4086