PET for Cardiac Sarcoid and Inflammation

Cardiac PET Scan for Detection of Sarcoidosis and Inflammation

Sarcoidosis is a multi-systemic granulomatous/inflammatory disease. It most commonly affects the lungs with presentation range from hilar adenopathy to severe interstitial lung disease and pulmonary hypertension. In addition to the lungs, sarcoidosis can affect other organs in the body including the heart. Approximately 5% of patients with pulmonary or systemic sarcoidosis have cardiac involvement, although this prevalence is thought to be underestimated. Cardiac sarcoidosis can result in cardiac arrhythmia such as atrioventricular block or ventricular arrhythmias, cardiomyopathy and heart failure. Advanced cardiac imaging including Cardiovascular MRI or Cardiac PET scan are the available, non-invasive, imaging techniques that can be utilized for diagnosis of cardiac sarcoidosis. According to the Heart Rhythm Society expert consensus statement on the diagnosis and management of arrhythmias associated with cardiac sarcoidosis (2014), advanced cardiac imaging is indicated in the following patients:

  • Patient WITH extracardiac sarcoidosis with 
    • Symptoms (significant palpitation, presyncope/syncope) OR
    • Abnormal ECG (complete left or right bundle branch block; unexplained pathologic Q waves in two or more leads; 2nd or 3rd degree AV block; or sustained/nonsustained VT) OR
    • Abnormal echocardiogram (regional wall motion abnormalities, and/or wall aneurysm and/or basal septum thinning and/or LVEF < 40%)
  • Patient WITHOUT extracardiac sarcoidosis
    • Unexplained second-degree Mobitz type II or third-degree AV block in adults aged <60 years.
    • Sustained monomorphic VT of unknown etiology (deemed reasonably by majority of the writing group but was not included as a formal recommendation)

The protocol of Cardiac PET scan for detection of cardiac sarcoidosis includes resting myocardial perfusion images (similar to resting images for routine cardiac PET stress test) to detect resting perfusion defect that can suggest myocardial scarring from sarcoidosis.   This is followed by FDG-PET images for detection of inflammatory process that typically occurs in cardiac sarcoidosis.  The patient preparation process including special dietary preparation prior to Cardiac PET scan is crucial for optimal imaging and to avoid any false positive findings. The information on dietary preparation for cardiac FDG-PET for sarcoidosis can be found here Dietary Prep for FDG-Sarcoid .