Clinical value of FDG PET in patients with fever of unknown origin and patients suspected of focal infection or inflammation

Abstract

Fever of unknown origin (FUO) and suspected focal infection or inflammation are challenging medical problems. The aim of this study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) in patients with FUO and patients with suspected focal infection or inflammation. All FDG PET scans ordered because of FUO or suspected focal infection or inflammation in the last 4 years were reviewed. These results were compared with the final diagnosis. Thirty-five FDG PET scans were performed in 35 patients with FUO. A final diagnosis was established in 19 patients (54%). Of the total number of scans, 37% were clinically helpful. The positive predictive value of FDG PET in these patients was 87% and the negative predictive value was 95%. Fifty-five FDG PET scans were performed in 48 patients with suspected focal infection or inflammation. A final diagnosis was established in 38 patients (82%). Of the total number of scans, 65% were clinically helpful. The positive predictive value of FDG PET in these 55 episodes of suspected infection or inflammation was 95% and the negative predictive value was 100%. It is concluded that FDG PET appears to be a valuable imaging technique in the evaluation of FUO and suspected focal infection or inflammation. Furthermore, FDG PET could become a useful tool for evaluating the effect of treatment of infectious and inflammatory processes that cannot reliably be visualised by conventional techniques. However, to assess the additional diagnostic value of this technique, prospective studies of FDG PET as part of a structured diagnostic protocol are warranted.

Determinants of diagnostic performance of 18F-FDG PET/CT in patients with fever of unknown origin

“…CT, computed tomography; 18 F-FDG, fluorine-18 fluorodeoxyglucose; FUO, fever of unknown origin. remained unclear in 39% of the FUO patients despite performing an 18 F-FDG PET/CT, which is within the average range of other publications of between 34 and 46% [14,15,28]. Furthermore, in 17% of the cases, 18 F-FDG PET/CT detected a cause of FUO, which had not been suspected on the basis of preceding reasoning and examinations including abdominal and chest CT.…”

“…In our study, 18 F-FDG PET/CT was performed despite a previous CT scan of the chest or the abdomen in 60% of the cases. However, early 18 F-FDG PET/CT may shorten the period of diagnostics and disease as well as save cost in the amount of 5471 euros per patient [29] as it may avoid the need for further futile investigations [14,15]. In our institution, the costs of a whole-body 18 F-FDG PET/CT are approximately twice as high as the cost of a contrast-enhanced CT of the thorax and abdomen.…”

“…Therefore, its use has increased markedly in the last few years for the diagnostic work-up of FUO [5,[13][14][15][16]. However, there is uncertainty in terms of the adequate timing at which an 18 F-FDG PET/CT is indicated in the diagnostic work-up of FUO.…”

Necrotizing Cervical Lymphadenitis Caused by Mycobacterium simiae in an HIV-Positive Patient: Imaging with 18F-FDG PET/CT

“…Treatment includes surgical excision of the involved nodes and a course of antibiotics, although M. simiae is the most drug-resistant of all non-tuberculous mycobacteriae, requiring combination therapy [1]. 18 F-FDG PET/CT is proving to be a valuable tool for detecting and localizing various infectious disease processes in immunocompetent [3][4][5][6] as well as immunocompromised patients [7][8][9][10][11][12]. The role of 18 F-FDG PET/CT imaging in HIV patients continues to be investigated [7,8]; however, initial results for detecting HIV-related infections and malignancies are promising.…”

The Diabetic Foot—Imaging Options and Considerations

“…21 Despite having high sensitivity for imaging areas of active infection, PET may not be as specific in identifying areas of abnormal tracer accumulation, which may be partly attributed to low spatial resolution. This limitation can be mitigated by combining PET with computed tomography (PET/CT), which improves diagnostic accuracy by allowing the co-registration of abnormal 18F-FDG uptake with specific anatomical structures.…”