Transthoracic echocardiography (TTE) is usually the initial investigation of suspected pericardial disease. It is cheap and widely available and has high accuracy for detecting pericardial effusions and signs of tamponade. TTE is also helpful for guiding diagnostic or therapeutic pericardiocentesis. Restricted acoustic windows limit its evaluation of the entire pericardium; loculated collections, intrapericardial blood clot, and pericardial thickening may be difficult to assess.CT and MR are indicated when TTE is inconclusive or when loculated or hemorrhagic effusion or pericardial thickening is suspectedIOC for aoic dissection-- MRI IOC for pericardial effusion= M- mode ECHOIOC for valvular disease = 2 D - ECHO IOC FOR RADIOTHERAPY CAUSED FIBROSIS= BIOPSY(Grainger and Allison&;s diagnostic radiology 6th edition, page 240)