18F-FDG PET/CT focal cardiac uptake: An unsuspected Chiari’s network

Abstract

We report a 71-year-old female patient in chemotherapy treatment for cervix carcinoma (FIGO stage IV) infiltrating the bladder and the left parametrium. PET imaging with 383 MBq of 18F-FDG revealed a hypermetabolic pelvic mass and metastatic disease with pathological lesions at the level of the liver, lung and bone parenchyma; being all suggestive of malignancy. Also, a focal uptake with nodular morphology in the right atria was found (arrow), making imperative to discard a metastatic etiology versus primary tumor (myxoma/sarcoma) and other etiologies. Given the aforementioned findings, a transesophageal echocardiography was performed with no evidence of intracavitary mass, showing a mobile fibrous net in the right atria known as Chiari’s Network (Figure 1). The Chiari’s network is a vestige of the venous sinus valve that favors the passage of oxygenated blood to the left atrium in the fetal stage. This finding has a prevalence of 2%, and it’s also related to arrhythmias, persistent foramen ovale and atrial septal aneurysm. Several articles reflect its paradoxical behaviour either as a filter and nidus for thrombus. Currently, there’s a lack of scientific evidence about the recommendation of surgical treatment, remaining to individual case decisions. Further examinations are mandatory when abnormal activities as focal cardiac uptake in the atria are observed during PET/CT.