2.2.3.5 Nuclear imaging

The incorporation of positron-emission tomography (PET) in the modified Duke's criteria is addressed to enhance the IE diagnosis in some situations where the

#### Figure 1.

Transesophageal echocardiogram: a hyperechoic lesion (red arrow) is seen at level of pulmonary valve, prolapsing to right ventricle outflow tract.

#### Right-Sided Infective Endocarditis DOI: http://dx.doi.org/10.5772/intechopen.85019

clinical suspicion is not always confirmed with the echocardiography. This imaging technique is especially valuable in the diagnosis of prosthetic valve infective endocarditis (PVIE) [5, 12].

There are also reports where the PET helped to determine the extension of pacemaker or defibrillator infection, consequently improving the adequate surgical intervention [13].

Peripheral embolic and metastatic infectious events can also be detected with this technique; nevertheless, their specificity is lower in brain septic emboli [5].

A correct interpretation of PET must be taken in some conditions which can make us misinterpret the findings, for instance, a recent cardiac surgery usually shows enhancement at the mediastinal area due to the inflammatory response. Some conditions can show similar patterns to that of IE, such as an active thrombus, soft atherosclerotic plaques, vasculitis, primary cardiac tumors, cardiac metastasis from a non-cardiac tumor, postsurgical inflammation, and foreign body reactions [5].
