Comments related to mycotic or infectious aneurysms are provided in a later section of this document. More study is needed to define the utility of 18 F-fluoro deoxyglucose positron emission tomography/CT in the diag- nosis and management of IE. In a prospective study of 25 IE F-fluorodeoxyglucose positron emission tomography/ CT was useful in identifying peripheral embolization in 11 patients and in detecting IE extracardiac manifestations in 7 patients who did not demonstrate any clinical manifestations The use of multimodality imaging in IE may increase in the future as the risks and benefits of each diagnostic tool are Table 5. Clinical and Echocardiographic Features That Suggest Potential Need for Surgical Intervention Vegetation Persistent vegetation after systemic embolization Anterior mitral leaflet vegetation, particularly with size >10 mm* 1 Embolic events during first 2 wk of antimicrobial therapy* Increase in vegetation size despite appropriate antimicrobial therapy* Valvular dysfunction Acute aortic or mitral insufficiency with signs of ventricular failure Heart failure unresponsive to medical therapy Valve perforation or rupture Perivalvular extension Valvular dehiscence, rupture, or fistula New heart block Large abscess or extension of abscess despite appropriate antimicrobial therapy See text for a more complete discussion of indications for surgery based on vegetation characterizations. *Surgery may be required because of risk of embolization. Surgery may be required because of heart failure or failure of medical therapy. Echocardiography should not be the primary modality used to detect or monitor heart block. Baddour et al Infective Endocarditis in Adults 1443 Antimicrobial Therapy Therapeutic Principles The primary goal of antibiotic treatment is to eradicate infection, including sterilizing vegetations, although the unique character- istics of infected vegetations can pose a variety of challenges. 