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The purpose of these guidelines is to assist physicians in recommending, performing, interpreting and reporting the results of FDG PET/CT for oncological imaging of adult patients. PET is a quantitative imaging technique and therefore requires a common quality control (QC)/quality assurance (QA) procedure to maintain the accuracy and precision of quantitation. Repeatability and reproducibility are two essential requirements for any quantitative measurement and/or imaging biomarker. Repeatability relates to the uncertainty in obtaining the same result in the same patient when he or she is examined more than once on the same system. However, imaging biomarkers should also have adequate reproducibility, i.e. the ability to yield the same result in the same patient when that patient is examined on different systems and at different imaging sites. Adequate repeatability and reproducibility are essential for the clinical management of patients and the use of FDG PET/CT within multicentre trials. A common standardised imaging procedure will help promote the appropriate use of FDG PET/CT imaging and increase the value of publications and, therefore, their contribution to evidence-based medicine. Moreover, consistency in numerical values between platforms and institutes that acquire the data will potentially enhance the role of semiquantitative and quantitative image interpretation. Precision and accuracy are additionally important as FDG PET/CT is used to evaluate tumour response as well as for diagnosis, prognosis and staging. Therefore both the previous and these new guidelines specifically aim to achieve standardised uptake value harmonisation in multicentre settings.

La sarcoidosis is a granulomatous disease of unknown etiology. It may mimic malignancy and may affect multiple organs, with a variable clinical course. Pancreatic involvement is very rare. We present the case of a 78-year-old woman with systemic sarcoidosis whose (18)F-FDG PET/CT scan showed a pancreatic lesion and multiple lymphatic (thoracic and non-thoracic) and visceral lesions. The abnormal (18)F-FDG uptake in the pancreas was limited to the tail. A second (18)F-FDG PET/CT study performed 4 months and 3 weeks after the first PET/CT, following corticosteroid therapy during three and a half months, evidenced partial regression of the disease, with persistent (18)F-FDG pathological uptake in the pancreatic lesion., (Copyright © 2010 Elsevier España, S.L. and SEMNIM. All rights reserved.)

We present the case of a male patient with gastrointestinal stromal tumor (GIST) in whom we conducted two (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) studies, the first one prior to beginning the treatment with Glivec and the second after one month of treatment. The first (18)F-FDG PET scan detected multiple FDG avid foci in distal esophagus, liver and in an interaortocava lymph node. The second (18)F-FDG PET showed very good response to therapy, with an almost complete disease remission. After 23 months of follow-up, the early response to treatment detected by (18)F-FDG PET was confirmed. The utility of (18)F-FDG PET in the evaluation of response to treatment in GIST is discussed and compared with CT.

Introduction: 18F-FDG PET has demonstrated its usefulness in detecting recurrences of differentiated thyroid cancer (DTC) with high thyroglobulin (Tg) levels and negative 131I whole-body scan (WBS); however, the number of patients analyzed is low and different studies report disparate results., Objective: To estimate the diagnostic accuracy of 18F-FDG PET in this subgroup of patients., Materials and Methods: Fifty eight patients (64 18F-FDG PET studies) with histologically proven DTC treated with total thyroidectomy followed by at least one session of 131I therapy for the ablation of thyroid remnants were retrospectively analyzed. Results were verified by pathology, clinical follow-up, response to treatment, or by comparison with conventional diagnostic methods. Sensitivity (Se), specificity (Sp), likelihood ratios (LR), diagnostic accuracy (DA), positive and negative predictive values (PPV, NPV), and Tg levels were calculated for patients with positive and negative 18F-FDG PET results., Results: Twenty seven studies were true positives, 1 false positive, 25 true negatives, and 11 false negatives. Se was 71 %, Sp 96 %, PPV 96.4 %; NPV 69.4 %, DA 81.3 %, positive LR 17.75, and negative LR 0.3. The mean Tg level was 202.34 ng/ml in patients with positive 18F-FDG PET and 40.94 ng/ml in those with negative 18F-FDG PET; the difference between the two groups (161.4 ng/ml) was significant at p <0.05., Conclusions: 18F-FDG PET is a useful for detecting residual or recurrent DTC in patients with elevated Tg and negative 131I WBS.

Aim: Renal cell carcinoma is the most frequent solid kidney tumor. At present, PET is not the imaging test of choice, the helical CT being the best method to assess these patients. The aim of the study was to perform a meta-analysis of the literature to evaluate the performance and accuracy of 18F-FDG PET in the detection of primary disease, recurrence and metastasis of renal cell carcinoma., Materials and Methods: A systematic search was done of the available literature in primary and secondary databases published until October 2004 indexed in MEDLINE and CANCERLIT. Exclusion/inclusion criteria were applied. Their quality was evaluated using the Flynn criteria and joint estimators of sensitivity (S), specificity (Sp), likelihood ratios (LR), diagnostic odds ratio (DOR) and summary ROC (SROC) curve were obtained. The presence of the threshold effect was evaluated and the summary ROC (SROC) curve was calculated., Results: Seven out of 46 studies fulfilled the inclusion criteria and were analyzed. Three studies evaluated the use of 18F-FDG PET in the differential diagnosis of renal masses. Two studies analyzed restaging and two analyzed the role of 18F-FDG PET in the detection of metastatic disease. All the selected studies were classified according to Flynn's criteria. We found the highest S in restaging with S 0.87 (95 % CI, 0.75-0.95) and in metastases detection with S 0.72 (95 % CI, 0.56-0.85) as well as the high Sp in differential diagnosis of renal masses., Conclusions: The results of this meta-analysis suggest that 18F-FDG PET can be useful in restaging and detection of metastatic disease, based on its acceptable S and Sp. However, the performance of 18F-FDG PET in the detection of primary disease is limited, but this may improve with the new PET/CT systems.

Background: This study aimed to assess the results obtained with the positron emission tomography (PET) and conventional anatomic imaging methods (CT scan and MRI) in the diagnosis of suspicion of tumor recurrence in head and neck cancers., Methods: Thirty patients with suspicion of tumor recurrence due to head and neck cancers were reviewed retrospectively. Consequently, 34 PET studies were performed. The images were obtained in the PET Institute of Madrid. They were interpreted by visual and semiquantitative analysis. The results were confirmed with clinical follow-up, response to treatment or with histological studies in some cases., Results: Sensitivity and specificity of the PET were 95.6% and 81.8% respectively, while it was 65% and 80% for the CT scan/MRI., Conclusions: We can conclude that PET provides better results than conventional imaging techniques in the detection of head and neck cancer recurrence.

Objective: To present the case report of a patient with undifferentiated and diffuse signet-ring cell gastric carcinoma in which FDG-PET evidenced recurrent disease., Materials and Methods: The patient was diagnosed of a stage III gastric carcinoma in 1994 and was treated with a subtotal gastrectomy. In February 2003, recurrent disease was detected in mediastinal and left supraclavicular lymph nodes. The patient was treated with chemotherapy and radiotherapy, reaching a complete response. After 6 months free of disease, he presented an elevation of the tumor markers with negative results in conventional imaging methods (upper digestive endoscopy, bone scintigraphy, and CT). An FDG-PET scan was performed to rule out recurrent disease., Results: FDG-PET detected pathologic findings suggestive of malignant disease in right supraclavicular and mediastinal lymph nodes. These findings were confirmed by clinical follow-up and with another CT scan performed 4 months later., Conclusions: In this case report we stress the importance of early recurrence by FDG-PET in a non-intestinal gastric carcinoma. This is of interest given the greater difficulty to detect mucous secreting and/or producing carcinomas with the PET-FDG.

Aim: The aim of this paper was to perform a meta-analysis of the literature to evaluate the accuracy of FDG-PET in recurrence detection in patients with ovarian cancer., Methods: The search strategy consisted in identifying papers published between November 1972 and October 2003 indexed in MEDLINE and CANCERLITE. Inclusion criteria were publications that evaluated recurrence with FDG-PET in patients with ovarian carcinoma. Exclusion criteria were duplicated papers or those outdated by subsequent ones. The statistical analysis included 95 % confidence intervals (CI) of sensitivity (S), specificity (Sp) and natural logarithm of the odds ratio (Ln OR)., Results: Seventeen publications fulfilled the inclusion criteria and were analyzed. The S and Sp were 0.94 (95% CI, 0.93-0.96) and 0.65 (95% CI, 0.46-0.85), respectively. The Ln OR presented global homogeneity and significant values in > 75% of the studies., Conclusion: According to our meta-analysis, FDG-PET has high S and intermediate Sp, with few false negative results. These preliminary findings suggest that FDG-PET may be an effective means of identifying patients with recurrent ovarian cancer.

Aim: Recurrent ovarian cancer is a major problem and an accurate diagnosis can often change patients' management. This study aimed to assess the impact on management of FDG-PET in recurrent ovarian cancer., Material and Methods: Forty-three patients in whom FDG-PET scan was performed due to suspected recurrent ovarian cancer were included. FDG-PET results were confirmed by histopathology and clinical follow-up of at least 12 months. To assess impact on management the treatment plan based on conventional imaging methods was compared with the treatment plan based on inclusion of PET findings, classifying FDG-PET impact on management as high, medium, low or no impact. Management changes, when present, were classified as intermodality or intramodality., Results: FDG-PET had a high impact on therapeutic management in 28 patients (65.1 %), medium impact in 2 patients (4.6 %), low impact in 9 patients (20.9 %), and no impact in 4 patients (9.3 %). FDG-PET induced an intermodality change in management in 27 patients (62,8 %); intramodality changes were induced in 3 patients (7 %). Finally, it produced no treatment changes in 13 patients (30.2 %)., Conclusion: FDG-PET supplied additional information when compared to conventional diagnostic procedures and allowed adequate management changes in most patients.