Session Information
Session Type: ACR Concurrent Abstract Session
Session Time: 2:30PM-4:00PM
Background/Purpose:
FUO and IUO are rare but diagnostically challenging clinical problems. Because of the abundance of differential diagnoses, a generally accepted diagnostic guideline has not yet been established. Besides a thorough medical history, physical examination, and laboratory testing, imaging techniques are important tools in the diagnostic workup of FUO and IUO. In the last few years, 18F-FDG-PET/CT has been found to be a suitable diagnostic tool for FUO/IUO, as it is able to detect inflammatory and malignant processes with a high spatial resolution.
Methods:
All patients presenting with FUO or IUO at the University Clinic of Erlangen between 2007 and 2014 were clinically documented and subjected to 18F-FDG-PET/CT scanning with a Siemens Biograph™ TruePoint™ PET/CT. Images were evaluated by specialists at the Departments of Nuclear Medicine and Radiology of the University Clinic of Erlangen. Final diagnosis as documented in the patients´ electronic charts was recorded. 18F-FDG-PET/CT scans were considered positive when a focal uptake of the tracer was detected additionally to the standard areas of physiological tracer uptake. 18F-FDG-PET/CT results were compared to the final diagnosis and classified as helpful or non-helpful in establishing the final diagnosis. Multivariate logistic regression was used to identify clinical parameters that correlated with a helpful 18F-FDG-PET/CT in patients with and without FUO as well as in patients with and without IUO.
Results:
Of the 236 patients enrolled 72 presented with FUO, 139 with IUO and 25 did not fulfill FUO or IUO criteria. 232 patients were included in the multivariate logistic regression model. Final diagnosis was established in 185 patients (78.4%, Table 1). In 123 (52.1% of all patients; 66.5% of diagnosed patients), the 18F-FDG-PET/CT was helpful in finding the diagnosis. The chance was higher in patients without fever (OR=0.252; p=0.001), those aged >50 years (p=0.016; p=0.005, respectively) and those with a CRP level >30 mg/dl (p=0.007; p=0.003, respectively) .
Conclusion:
Our study shows that if the standard diagnostic tests (laboratory, chest x-ray and abdominal ultrasound) did not identify the cause of FUO/IUO, 18F-FDG-PET/CT scanning should be applied in the early stage of the diagnostic process. An early use of a 18F-FDG-PET/CT is especially helpful to establish a final diagnosis in patients with an elevated C-reactive protein and age over 50 years.
|
Category |
N (%) FUO patients in category |
N (%) IUO patients in category |
N (%) non-FUO/IUO patients in category |
|
Infection |
11 (15.3%) |
17 (12.2%) |
0 (0%) |
|
Malignancy |
5 (6.9%) |
11 (7.9%) |
2 (8.0%) |
|
Chronic inflammatory diseases 1. Large vessel vasculitis 2. Polymyalgia rheumatica 3. Still’s disease 4. IgG4-related disease 5. Others |
35 (48.6%) 5 (6.9%) 4 (5.6%) 11 (15.3%) 1 (1.4%) 14 (19.4%) |
86 (61.9%) 29 (20.9%) 25 (18%) 0 (0%) 4 (2.9%) 28 (20.1%) |
10 (40.0%) 1 (4%) 0 (0%) 0 (0%) 4 (16%) 5 (20%) |
|
Miscellaneous |
1 (1.4%) |
2 (1.4%) |
6 (24.0%) |
|
No Diagnosis |
20 (27.8%) |
23 (16.5%) |
7 (28.0%) |
|
Total |
72 (100%) |
139 (100%) |
25 (100%) |
To cite this abstract in AMA style:
Schönau V, Vogel K, Englbrecht M, Manger B, Schmidt D, Kuwert T, Schett G. Fever of Unknown Origin (FUO) and Inflammation of Unknown Origin (IUO): Is 18f-FDG-PET/CT a Useful First Line Diagnostic Strategy? [abstract]. Arthritis Rheumatol. 2015; 67 (suppl 10). https://acrabstracts.org/abstract/fever-of-unknown-origin-fuo-and-inflammation-of-unknown-origin-iuo-is-18f-fdg-petct-a-useful-first-line-diagnostic-strategy/. Accessed .« Back to 2015 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/fever-of-unknown-origin-fuo-and-inflammation-of-unknown-origin-iuo-is-18f-fdg-petct-a-useful-first-line-diagnostic-strategy/