Cardiac Sarcoidosis in a Patient With Hypertrophic Cardiomyopathy Demonstrated by Magnetic Resonance Imaging and Single Photon Emission Computed Tomography Dual-Isotope Scintigraphy
A 41-year-old man, who had been diagnosed with stage 2 pulmonary sarcoidosis 3 years earlier, was referred to the cardiac clinic complaining of palpitations, dyspnea, and atypical chest pain. Except for central obesity (body mass index of 37 kg/m2) and hypertension, no abnormalities were found on physical examination. The 12-lead ECG demonstrated apical and inferolateral ST-segment elevation, whereas multiple polymorphic premature ventricular beats were found during exercise testing and 24-hour ambulatory ECG.
Coronary angiography showed no abnormalities. Because of the man’s obesity, the image quality of the transthoracic echocardiography was suboptimal. Cardiac MRI revealed severe asymmetric hypertrophy of the left ventricle, a finding that points to hypertrophic cardiomyopathy. T2-weighted cardiac MRI revealed increased signal in the apical region (Figure 1), and contrast-enhanced cardiac MRI (0.1 mmol/kg gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA]) showed late enhancement of the same region (Figures 2 through 5⇓⇓⇓).
A dual-isotope 99mTc-Hexamibi (Cardiolite, DuPont) and 111In-pentetreotide (OctreoScan, Tyco Healthcare, Mallinckrodt Medical BV; dose 190 MBq) SPECT was performed during exercise (dose 280 MBq) and rest (dose 870 MBq), revealing a reversible apical perfusion defect and apical uptake of 111Inpentetreotide (Figure 6). The presence of somatostatin receptors in the apical region suggests active apical cardiac sarcoidosis.
The SPECT and cardiac MRI images were fused (Figures 7 and 8⇓) by rigid-body transformations based on anatomic landmarks (apex and basal interventricular septum) and the geometric dimensions identified in the different types of images. The spatial image transformations were computed in the MatLab (MathWorks) programming environment. 111In-pentetreotide binds to somatostatin receptors on macrophages and has been reported to be useful in the management of sarcoidosis. It is possible to differentiate between active inflammation and fibrosis with different cardiac MRI techniques (eg, T2-weighted versus contrast-enhanced T1-weighted cardiac MRI).
This case demonstrates the usefulness of matching different imaging techniques to visualize inflammation and the different stages of this process in the myocardium.
The authors thank Geert J. Ensing, PhD, Tyco Healthcare, Mallinckrodt Medical BV, Petten, the Netherlands, for providing us with 111In-pentetreotide.