Apical Hypertrophy Caused by Glycogen Storage Disease Creating Artifacts in Myocardial Perfusion Imaging

A 46-year-old man with atrial fibrillation and coronary artery disease was referred for myocardial perfusion imaging for the evaluation of chest pain. The patient underwent adenosine stress and rest dual-isotope myocardial perfusion imaging. There was no adenosine-induced chest pain or EKG changes specific for ischemia. Myocardial perfusion images demonstrated an apical “hot spot” and decreased tracer activity in the base of the heart. The polar plots showed a bright center with a rim of significant (>2.5 SD) defect around the base of the myocardium. Ischemia in the base of the heart, with the apex of the heart seemingly normal, was rather puzzling and correlation with magnetic resonance images (MRI) showed apical hypertrophy. Examination of the history revealed that the patient was diagnosed with restrictive cardiomyopathy 2 years ago and endocardial biopsy showed intramyocardial glycogen on electron microscopy, suggesting glycogen storage disease. The case illustrates a “hot spot” resulting from apical hypertrophy creating artifactual fixed defects in myocardial perfusion images and in polar maps.