Final answer:
The probable diagnosis for the dense echoes noted posterior to normal mitral valve leaflets on M-mode/two-dimensional echocardiography is vegetation (D). Infective endocarditis is a condition characterized by the formation of vegetations, which are clumps of bacteria and fibrin that adhere to the mitral valve leaflets.
Step-by-step explanation:
The probable diagnosis for the dense echoes noted posterior to normal mitral valve leaflets on M-mode/two-dimensional echocardiography is vegetation (D).
Infective endocarditis is a condition characterized by the formation of vegetations, which are clumps of bacteria and fibrin that adhere to the mitral valve leaflets. These vegetations can be visualized as dense echoes on echocardiography.
Annular calcification (A), fibrosis (B), and papilloma (C) are not typically associated with the presence of dense echoes on echocardiography.