Imaging of Cardiac Sarcoid Lesions Using Fasting Cardiac 18F-Fluorodeoxyglucose Positron Emission Tomography: An Autopsy Case
A 57-year-old man with a permanent pacemaker implanted for complete atrioventricular block was referred to our hospital for progressive dyspnea in July 2006. Chest x-ray showed cardiac enlargement, and cardiac ultrasound exhibited diffusely reduced wall motion of the left ventricle. Ejection fraction was 29%. Chest computed tomography revealed multiple nodular lesions in both lungs, which were pathologically diagnosed as pulmonary sarcoidosis by transbronchial lung biopsy. On fasting cardiac 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), localized uptake of FDG was noted in the anterior, septal, and inferior walls of the left ventricle (Figure, A). With a diagnosis of cardiac sarcoidosis, oral predonisolone was started at 30 mg daily in October 2006. Two months later, however, he was transported to our hospital with cardiopulmonary arrest.
An autopsy was performed, and noncaseating granuloma with Langhans-type giant cells were noted in the lung, spleen, and, more prominently, heart. Lesion activity of the cardiac sarcoid lesions varied depending on the site in the heart. Red areas (Figure, B) indicate active glanulomatous lesions with Langerhans-type giant cells and lymphocyte infiltration. Blue areas indicate lesions with less inflammatory cell infiltration along with reactive fibrosis, and black areas reveal more progressed lesions with hyalinized scar tissue. The distribution of these sarcoid lesions in the heart corresponded well with that of FDG uptake (Figure, A). FDG accumulated even in the hyalinized lesions probably because such progressed lesions were still in the active phase when FDG-PET images were obtained before steroid treatment.
Studies have suggested that abnormal cardiac FDG uptake reveals the presence of active sarcoid lesions in patients with sarcoidosis.1,2 However, no reports have compared the cardiac FDG-PET images with the corresponding gross pathology of a whole heart. The present autopsy case demonstrated that FDG uptake represents the presence of myocardial sarcoid lesions, further suggesting the promising role of FDG-PET in the diagnosis of cardiac sarcoidosis.
Ishimaru S, Tsujino I, Takei T, Tsukamoto E, Sakaue S, Kamigaki M, Ito N, Ohira H, Ikeda D, Tamaki N, Nishimura M. Focal uptake on 18F- fluoro-2-deoxyglucose positron emission tomography images indicates cardiac involvement of sarcoidosis. Eur Heart J. 2005; 26: 1538–1543.
Tadamura E, Yamamuro M, Kubo S, Kanao S, Hosokawa R, Kimura T, Kita T, Togashi K. Multimodality imaging of cardiac sarcoidosis before and after steroid therapy. Circulation. 2006; 113: e771–e773.