0319: Long standing fever in patients with cardiovascular prostheses: role of 18-fluoro deoxyglucose positron computer tomography combined with computerized tomography in diagnosis and management

Abstract

the diagnosis of infected protheses in patients with long standing fever is difficult, challenging and has major impact on the management. Since 18-Fluo Desoxyglucose positron emission tomography performed together with computerized tomography (FDG PET-CT) has a role in the diagnosis and localization of infection; we evaluated its value in the diagnosis of infected prostheses, correlating its results with medical workup, echo-cardiogram and dedicated CT. Patients: Fourteen patients (pts) with cardiovascular prostheses (seven with a pacemaker, four with vascular grafts, two with pulmonary stent and one with mitral valve prosthesis were hospitalized for prolonged fever. All pts received antibiotics and underwent repeated medical workup. Eight of the 14 pts had a proven bacteriemia. Transthoracic and transoesophagial echocardiogram was performed as well as CT, for most of them. FDG PET-CT was performed in all of them, following injection of 370 MBq of F-18 FDG. All patients were normoglycemic at the time of injection. Results of the FDG PET-CT were compared with other diagnostic modalities and clinical follow up. In the 7 pts with pacemaker, FDG PET-CT was positive in 4, echo in 2/4. IN 3/4 the device was removed. A new pacemaker was implanted for two patients after few weeks. FEG PET-CT was negative in 3/7 pts with 1 positive, 1 negative and 1 intermediate results. All patients with vascular graft had positive FDG PET-CT scan and only one had a positive echocardiogram. This patient had a surgical proven abscess. Two pts with pulmonary stent had a positive FDG PET-CT scan and 1 positive echo. In this patient the stent extracted was infected. FDG PET-CT and echo was negative in the patient with mitral prosthesis.Conventional CT was positive in only 1 patient. Twelve pts return to normal including all the patients after prostheses extraction except one who died during graft replacement. FDG PET -CT is a useful tool for the diagnosis of infected cardiovascular prosthesis and is more accurate than stand alone CT. Correlation of the clinical, echo and FDG PET CT findings is crucial for the therapeutic decision.