Clinical impact of 18F-FDG-PET/CT in the extra cardiac work-up of patients with infective endocarditis

Objective The purpose of this study was to assess the clinical importance of F-18-FDG-PET/CT used in the extra cardiac work-up of patients with infective endocarditis (IE). Background IE is a serious condition with a significant mortality. Besides the degree of valvular involvement, the prognosis relies crucially on the presence of systemic infectious embolism. Methods Seventy-two patients (71% males and mean age 63 +/- 17 years) with IE were evaluated with F-18-FDG-PET/CT in addition to standard work-up including patient history, physical examination, conventional imaging modalities, and weekly interdisciplinary conferences. When previous unknown lesions detected by F-18-FDG-PET/CT were confirmed by succeeding examinations, they were considered true positive new findings and were further assessed for their clinical importance. Number needed to investigate was calculated as the number of patients who needed to undergo F-18-FDG-PET/CT to find at least one clinical important true positive new finding, not identified by standard work-up prior to F-18-FDG-PET/CT. Results F-18-FDG-PET/CT detected 114 lesions and 64 were true positive, of which 25 were new findings and detected in 17 patients. In 11 patients, the lesions were considered to have a clinical importance; osteomyelitis (n = 7), iliopsoas abscess (n = 1), gastrointestinal lesions (n = 2), and vascular prosthetic graft (n = 1). Number needed to investigate was 7 (11 of 72 patients). Conclusions F-18-FDG-PET/CT detected lesions of clinical importance in one of seven IE patients and may be a substantial imaging technique for tracing peripheral infectious embolism due to IE. Thus, F-18-FDG-PET/CT may help to guide adequate therapy and thereby improve the prognosis of patients with IE.