Not All Heart Uptakes On Tc-99m-Dpd Scintigraphy Are Amyloidosis Chloroquine-Induced Cardiomyopathy

This was the case of a 61-year-old woman with a medical history significant for hypertension and rheumatoid arthritis treated with chloroquine for the last 10 years. She was admitted to our hospital for heart failure symptoms. Echocardiography revealed severe concentric left ventricular hypertrophy. Serum and urine immunofixation electrophoresis and serum light chain assay were negative. No late gadolinium enhancement was observed on cardiovascular magnetic resonance. Tc-Tc-DPD (3,3-diphosphono-1,2-propanodicarboxylic acid) scintigraphy showed myocardial uptake (Perugini score 2/3). Genetic testing excluded hereditary transthyretin cardiac amyloidosis. Endomyocardial biopsy analysis did not show findings suggestive of amyloidosis but consistent with chloroquine toxicity. Chloroquine-mediated cardiotoxicity is rare, and there are very few reports about bone scintigraphy imaging features.