1.
Nuclear Medicine Imaging in Fever of Unknown Origin: The New Paradigm.
Palestro, CJ, Love, C
Current pharmaceutical design. 2018;(7):814-820
Abstract
Fever of Unknown Origin, or FUO, is a challenging condition for patients and clinicians. In up to 50% of cases, no diagnosis is established. Patient workup begins with comprehensive history, physical examination and laboratory tests. Radionuclide imaging has been a second-line procedure. Gallium-67 citrate, which accumulates in infection, inflammation, and tumor, was for many years, the radionuclide test of choice in the workup of FUO. The 24-72 hours between injection and imaging, relatively high radiation dose to patients, and suboptimal image quality are significant disadvantages; imaging results are variable. Although labeled leukocyte imaging accurately localizes infection, infections cause only about 20%-40% of all FUO's. In most cases, this test is not helpful in identifying the source of the fever. Fluorine-18-fluorodeoxyglucose (FDG) uptake is related to cellular glucose metabolism. Increased FDG uptake is present in numerous hypermetabolic conditions, including tumor, infection, and noninfectious inflammation. FDG positron emission tomography (PET) and PET/computed tomography (CT) have rapidly assumed an increasingly important role in the diagnostic workup of patients with FUO. FDG is especially useful for localizing lesions and areas of interest for further evaluation. In contrast to gallium and labeled leukocyte imaging, FDG contributes useful information in children with FUO. Initially utilized as a second-line diagnostic tool in patients with FUO, recent data indicate that FDG contributes more diagnostically useful information than anatomic imaging like ultrasound and CT, which leads to earlier institution of appropriate therapy. These findings suggest that FDG imaging should be performed earlier, rather than later, in the diagnostic evaluation of the patient with FUO.
2.
[Usefulness of (18)FDG PET-CT scan as a diagnostic tool of fever of unknown origin].
García-Gómez, FJ, Acevedo-Báñez, I, Martínez-Castillo, R, García-Gutiérrez, M, Tirado-Hospital, JL, Borrego-Dorado, I
Medicina clinica. 2015;(2):62-6
Abstract
BACKGROUND AND OBJECTIVE Classic fever of unknown origin (FUO) is defined as the presence of fever greater than 38.3°C of at least 3 weeks with an uncertain diagnosis. Identification of the etiology is crucial in guiding further diagnostic procedures and subsequent patient management. The aim of this study was to evaluate the role of fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography combined with computed tomography (PET/CT) in the diagnostic orientation of FUO. MATERIAL AND METHOD An observational retrospective study was performed, including 30 consecutive patients who had been studied between March 2010 and September 2013. Twenty-six out of 30 patients (86.67%) had a definitive diagnosis after pathologic confirmation in 15 cases, microbiological findings in one patient and clinical and radiological follow-up in 10 patients (mean: 16.38 months). RESULTS Among the positive scans, malignancy (n=10), inflammatory (n=8), infectious (n=4) and miscellaneous causes (n=1) were identified. (18)F-FDG PET/CT had a diagnostic accuracy of 90.00%, sensitivity of 88.46% (95% confidence interval [95% CI] 76-101), specificity of 100.00% (95% CI 100-100), positive predictive values of 100.00% (95% CI100-100) and negative predictive value of 57.14% (95% CI 20-91). CONCLUSIONS (18)F-FDG PET/CT provided useful for the etiologic diagnosis of FUO, with high sensitivity and specificity. (18)F-FDG PET/CT has an incremental morphological and functional value, especially indicating the best biopsy site.
3.
Imaging in infections of the left iliac fossa.
Le Pennec, V, Hourna, E, Schmutz, G, Pelage, JP
Diagnostic and interventional imaging. 2012;(6):466-72
Abstract
The main organs in the left iliac fossa are the descending colon, sigmoid colon and, in women, internal reproductive organs. An infection of the left iliac fossa must lead the clinician firstly to suspect diverticulitis of the sigmoid colon in older patients and salpingitis in women of childbearing age. Other less common aetiologies are possible (inflammatory or infectious colitis, epiploic appendagitis, abscess of the psoas, pyelonephritis, renal abscess, etc.). Sonography as a first-line investigation may lead to diagnosis (especially in gynaecological disease), but a CT scan with intravenous injection of an iodine-containing contrast medium will allow for a full assessment of disease spread, and complications of sigmoid colitis or its differential diagnoses (abscess, fistula, perforation) to be investigated. It can also be used to guide percutaneous drainage or fine-needle aspiration for microbiology investigations.
4.
Functional imaging of infection: conventional nuclear medicine agents and the expanding role of 18-F-FDG PET.
Parisi, MT
Pediatric radiology. 2011;(7):803-10
Abstract
A growing body of literature suggests that 18-fluorine fluorodeoxyglucose positron emission tomography ((18)F-FDG PET), particularly when combined with CT, is a useful tool for the detection of infectious and inflammatory disease processes. This article will briefly review the data to date on the use of FDG PET in diagnosing musculoskeletal infections and fever of unknown origin, comparing it to conventional scintigraphic techniques in both adults and, when available, in children.
5.
The role of nuclear medicine in infection and inflammation.
Becker, W, Meller, J
The Lancet. Infectious diseases. 2001;(5):326-33
Abstract
Investigators have used various techniques and radionuclides such as 51Cr and 32P-diisofluorophosphate to label blood cells and to study cell survival. Early studies also used these radionuclides to label human leucocytes for cell survival by in-vitro counting. But external imaging could not be done with these agents. Starting with the use of the gamma-emitting radionuclide (111)In-oxine for in-vitro labelling of phagocytic leucocytes, external imaging became possible. This method was the basis of visualisation of cell distribution within the body. Because an abscess consists primarily of leucocytes, leucocytes labelled with (111)In localise within the abscess and are detectable by imaging. Nowadays other radiopharmaceuticals with other underlying uptake mechanisms are also used to detect inflammatory or infectious foci in patients. Nuclear medicine can be most useful in patients with fever of unknown origin, where a focus has to be defined, or in patients where a lesion is known by clinical symptoms or by a radiological imaging and the differentiation between infection and other pathologies has to be made.