Pericardial cyst. Scan needed for this?

Is pet scan needed for this ?STUDY PROCEDURE:- In suspended respiration, volumetric acquisition of CT thorax & abdomen was taken with and without non-ionic iodinated IV contrast agent followed by multiplanar axial, coronal and sagittal reconstructions. OBSERVATION • A well defined hypodense non enhancing lesion of size measuring ~ 2 x 3 x 1.8 cm is seen in the aortopulmonary window. No significant mas effect on surrounding structures. IMPRESSION: In a F/U/C/O Left vocal cord palsy, the present scan shows: • A well defined hypodense non enhancing lesion seen in the aortopulmonary window--likely benign etiology, D/d: 1) Pericardial cyst 2) Loculated pericardial effusion. • There is medialization of posterior margin of lefttrue vocal cord with dilatation of left laryngeal ventricle & left pyriform fossa and obliteration of right pyriform fossa.