Step-by-step diagnostic algorithm for cardiac masses using cardiovascular imaging. Patient’s history, clinical data and ECG should be acquired and evaluated before extensive imaging work-up. With data extracted by the clinical evaluation and the TTE, a physician may initiate differential diagnosis and plan further work-up approach. When the mass is proved to be a thrombus (consider using ultrasound enhancing agents) no further work-up is needed. When thrombus is found on a prosthetic valve, TEE and/or CT can also be used. The next step is TEE especially for atrial masses. When the mass is vegetation or abscess then usually no-further work up is needed (consider PET scan as next best step when diagnosis is still under question). For other masses CMR is the next best step and guides further work-up which could include CT, or 18F FDG * For ventricular masses which are not adjacent to the cardiac valves and are not highly mobile, CMR can be alternatively used after the transthoracic echocardiogram without the need of TEE.