Role Of 18F-FDG Positron Emission Tomography Research Articles

18F-FDG PET for diagnosing painful arthroplasty/prosthetic joint infection

Up to now, there were some studies about the role of 18F-FDG PET or PET/CT in the diagnosis of prosthetic joint infection after arthroplasty with different values of sensitivity and specificity. The purpose of this study was to systematically review the published data regarding the diagnostic performance of positron emission tomography (PET) or PET/computed tomography (PET/CT) in prosthetic infection after arthroplasty. A comprehensive computer literature search of studies published regarding PET or PET/CT in patients suspicious of prosthetic infection was performed. Pooled sensitivity, specificity and area under the receiver operating characteristic (ROC) curve of PET or PET/CT in patients suspicious of prosthetic infection on a per prosthesis-based analysis were calculated. Sixteen studies comprising 1101 prosthesis with suspicious of prosthetic infection after arthroplasty were included in this meta-analysis. The pooled sensitivity of PET or PET/CT in detecting prosthetic infection was 87% [95% confidence interval (CI) 83–90%] on a per prosthesis-based analysis. The pooled specificity of PET or PET/CT in detecting prosthetic infection was 87% (95% CI 85–89%) on a per prosthesis-based analysis. The area under the ROC curve was 0.94 on a per prosthesis-based analysis. 18F-FDG PET or PET/CT demonstrated high sensitivity and specificity in subjects suspicious of prosthetic infection. However, various degrees of uptake in the asymptomatic patients are very common. Physicians should recognize these characteristics, and then 18F-FDG PET or PET/CT can act as an effective method in the diagnosis of prosthetic infection.

Positron emission tomography with 18F-FDG in the evaluation of patients with rheumatoid arthritis - a systematic review

IntroductionRheumatoid arthritis (RA) is a disease characterized by inflammation of the synovial membrane. Several authors have investigated the role of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (18F-FDG) in RA. ObjectivesTo systematically review the current literature on the role of 18F-FDG PET in the diagnosis, determination of disease activity and assessment of treatment response in patients with RA. MethodsSearches were conducted in Medline, Cochrane Library, Lilacs, Pubmed and Scopus in Portuguese, English and Spanish languages, using the keywords «rheumatoid arthritis», «synovitis», «FDG», «PET», «glycolytic metabolism» and «disease activity». ResultsOne hundred and forty-two articles were initially identified, of which only 40 were related directly to the subject. Twelve original articles and three case reports that met the inclusion criteria were selected. DiscussionThe presence of activated macrophages and fibroblasts in pannus are responsible for the intense periarticular uptake of 18F-FDG. The uptake patterns do not allow the differential diagnosis with other arthritides. The uptake intensity and the number of joints involved are metabolic parameters of disease activity that correlate well with the composite indices. Longitudinal studies of PET have proven useful in assessing the response to treatment with anti-TNF. When performed early, PET can predict the therapeutic response. ConclusionAlthough the actual role of this new technique for the investigation of RA is not yet established, 18F-FDG PET is a promising tool in determining the activity and prediction of response to treatment of patients with RA.

Role of 18F-FDG PET in detecting primary site in the patient with primary unknown carcinoma

The aim of this study was to verify the effectiveness of positron emission tomography (PET) in detecting primary sites in carcinoma of unknown primary (CUP) patients. In this study, CUP represented a group of heterogeneous tumors that shared the clinical manifestation of metastatic carcinoma with no obvious primary site at the time of first diagnosis, which included clinical investigations, computed tomography, magnetic resonance imaging and panendoscopy. We reviewed the records of 24 patients with CUP between January 1995 and December 2009. The patients who demonstrated additional tracer uptake sites other than previously known metastatic lesions by PET scan were done direct biopsies for the sites of accumulation. Patients who had a negative PET scan or for whom the primary site could not be identified by direct biopsies underwent examination under anesthesia of the at-risk occult tumor sites. PET scan demonstrated focal accumulation suspicious for primary tumor in 12 (50.0%) of 24 patients: tonsil 5, nasopharynx 3, hypopharynx 1, tongue 1, larynx 1, and maxillary sinus 1. A subsequent biopsy of these sites revealed primary cancer in 9 (37.5%) of 24 patients: tonsil 5, nasopharynx 1, hypopharynx 1, tongue 1, and maxillary sinus 1. In the remaining three patients, no malignant cells were found by the biopsy of the accumulated area: nasopharynx 2, larynx 1. PET scans increase the yield of primary tumor by 37.5%. The sensitivity, specificity for PET scan were 80.8, 76.9%, respectively. PET scanning is useful in detecting primary cancer of CUP patients.

La TEP au 18F-FDG dans la pathologie inflammatoire et infectieuse : intestinale, prothétique, fibrose, sarcoïdose, tuberculose…

Nuclear medicine plays an important role in the evaluation of infection and inflammation. A variety of diagnostic methods are available for imaging this inflammation and infection, most notably computed tomography, 68Ga scintigraphy or radionuclide labeled leucocytes. Fluorine 18 fluorodeoxyglucose ( 18F-FDG) is a readily available radiotracer that offers rapid, exquisitely sensitive high-resolution images by positron emission tomography (PET). Inflammation can be acute or chronic, the former showing predominantly neutrophilic granulocyte infiltrates, whereas in the latter, macrophages predominate. FDG uptake in infection is based on the fact that mononuclear cells and granulocytes use large quantities of glucose by way of the hexose monophosphate shunts. 18F-FDG PET accurately helps diagnose spinal osteomyelitis, diabetic foot and in inflammatory conditions such as sarcoidosis and tuberculosis.(it appears to be useful for defining the extent of disease and monitoring response to treatment). 18F-FDG PET can also help localize the source of fever of undetermined origin, thereby guiding additional testing. 18F-FDG PET may be of limited usefulness in postoperative patients and in patients with a failed joint prosthesis or bowel inflammatory disease. In this review, we will focus on the role of 18F-FDG PET in the management of patients with inflammation or suspected or confirmed infection.

The role of 18F-fluorodeoxyglucose positron emission tomography in gestational trophoblastic tumours: a pilot study

We conducted a pilot trial to evaluate the value of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in gestational trophoblastic tumours (GTTs). Patients with placental site trophoblastic tumour (PSTT), high-risk GTT (World Health Organisation score > or =8, disease onset at postpartum or greater than 6 months after antecedent pregnancy), metastatic GTT, recurrent/resistant GTT after chemotherapy, or post-molar GTT with unexplained abnormal beta-hCG regression and patients undergoing re-evaluation after salvage treatment were enrolled. PET was undertaken within 1 week after computed tomography (CT). Clinical impacts of additional PET were determined on a scan basis. A total of 14 patients were recruited. Sixteen PET scans were performed, with one patient having three serial studies. Benefits of additional PET were seen in 7 of 16 (43.8%) scans; these benefits included disclosure of chemotherapy-resistant lesions (n = 2), exclusion of false-positive CT lesions (n = 1), detection of an additional lesion not found by conventional imaging (n = 1) in high-risk GTT at the start of primary chemotherapy, and confirmation of complete response to treatment for PSTT or to salvage therapy for recurrent/resistant GTT (n = 3). On the other hand, in two instances there were false-negative PET findings, six scans yielded no benefit, and one showed an indeterminate lesion. Our preliminary results suggest that 18F-FDG PET is potentially useful in selected patients with GTT by providing precise mapping of metastases and tumour extent upfront, by monitoring treatment response and by localising viable tumours after chemotherapy. A larger study is necessary to further define the role of 18F-FDG PET in GTT.