Use Of 18F-FDG PET Research Articles

Prognostic Significance of Pretreatment Staging With 18F-FDG PET in Esophageal Cancer: A Nationwide Population-Based Study.

Purpose of the ReportWithout the routine use of 18F-FDG PET for initial staging of esophageal cancer, it may lead to inaccurate staging and suboptimal treatment. The purpose of this study was to evaluate the prognostic significance of pretreatment 18F-FDG PET in nonmetastatic esophageal cancer by comparing the survival between patients with and without pretreatment PET.Materials and MethodsWe selected newly diagnosed esophageal cancer patients without metastasis between 2009 and 2015 from Taiwan Cancer Registry and National Health Insurance Research Database. Pretreatment 18F-FDG PET staging was determined according to the implementation of PET within 90 days before starting treatment. Overall survival was calculated from the day of treatment initiation to the death from any cause. Survival curves were compared between patients with and without PET staging using the log-rank test.ResultsOf the 9078 patients included, 1765 (19.4%) and 7313 (80.6%) patients were staged with and without pretreatment PET, respectively. The median follow-up time for all patients and survivors was 1.29 years and 5.46 years, respectively. The pretreatment PET group had a lower risk of death than the no pretreatment PET group (hazards ratio, 0.74; 95% confidence interval, 0.70–0.79; P < 0.001). After adjusting for age, stage, histology, and tumor location, pretreatment PET remained significantly correlated with a lower risk of death (hazards ratio, 0.78; 95% confidence interval, 0.73–0.83; P < 0.001).ConclusionsThe utilization of pretreatment 18F-FDG PET for staging in nonmetastatic esophageal malignancy is associated with a lower risk of death even after adjusting for age, stage, histology, and tumor location.

Impact of 18F-FDG PET, PET/CT, and PET/MRI on Staging and Management as an Initial Staging Modality in Breast Cancer: A Systematic Review and Meta-analysis.

We performed a systematic review and meta-analysis to evaluate the impact of 18F-FDG PET, PET/CT, and PET/MRI on staging and management during the initial staging of breast cancer. We searched the PubMed, Embase, Cochrane Library, and KoreaMed databases until March 2020 to identify studies that reported the proportion of breast cancer patients whose clinical stage or management were changed after PET scans. The proportion of changes was pooled using a random-effects model. Subgroup and metaregression analyses were performed to explore heterogeneity. We included 29 studies (4276 patients). The pooled proportions of changes in stage and management were 25% (95% confidence interval [CI], 21%-30%) and 18% (95% CI, 14%-23%), respectively. When stage changes were stratified according to initial stage, the pooled proportions were 11% (95% CI, 3%-22%) in stage I, 20% (95% CI, 16%-24%) in stage II, and 34% (95% CI, 27%-42%) in stage III. The relative proportions of intermodality and intention-to-treat changes were 74% and 70%, respectively. Using metaregression analyses, the mean age and the proportion of initial stage III to IV and histologic grade II to III were significant factors affecting the heterogeneity in changes in stage or management. Currently available literature suggests that the use of 18F-FDG PET, PET/CT, or PET/MRI leads to significant modification of staging and treatment in newly diagnosed breast cancer patients. Therefore, there may be a role for routine clinical use of PET imaging for the initial staging of breast cancer.

18F-fluorodeoxyglucose positron emission tomography as a window into human dengue pathophysiology

In mouse models of dengue virus (DENV) infection, 18F-FDG PET is able to sensitively detect tissue-specific sites of inflammation and disease activity, as well as track therapeutic response to anti- DENV agents. However, the use of 18F-FDG PET to study the pathogenesis of inflammation and disease activity in DENV infection in humans, has not been clinically validated. Here we report the 18F-FDG PET imaging results of two patients during the febrile phase of acute DENV infection, paired with serial serum viral load, NS1 and proinflammatory cytokine measurements. Our findings demonstrate that 18F-FDG PET is able to sensitively detect and quantify organ-specific inflammation in the lymph nodes and spleen, in classic acute dengue fever. This raises the potential for 18F-FDG PET to be used as a research tool that may provide further insights into disease pathogenesis.

Prognostic value of 18F-FDG PET and PET/CT for assessment of treatment response to neoadjuvant chemotherapy in breast cancer: a systematic review and meta-analysis

BackgroundWe performed a systematic review and meta-analysis to evaluate the prognostic significance of 18F-FDG PET and PET/CT for evaluation of responses to neoadjuvant chemotherapy (NAC) in breast cancer patients.MethodsWe searched PubMed, Embase, and the Cochrane Library databases until June 2020 to identify studies that assessed the prognostic value of 18F-FDG PET scans during or after NAC with regard to overall (OS) and disease-free survival (DFS). Hazard ratios (HRs) and their 95% confidence intervals (CIs) were pooled meta-analytically using a random-effects model.ResultsTwenty-one studies consisting of 1630 patients were included in the qualitative synthesis. Twelve studies investigated the use of PET scans for interim response evaluation (during NAC) and 10 studies assessed post-treatment PET evaluation (after NAC). The most widely evaluated parameter distinguishing metabolic responders from poor responders on interim or post-treatment PET scans was %ΔSUVmax, defined as the percent reduction of SUVmax compared to baseline PET, followed by SUVmax and complete metabolic response (CMR). For the 17 studies included in the meta-analysis, the pooled HR of metabolic responses on DFS was 0.21 (95% confidence interval [CI], 0.14–0.32) for interim PET scans and 0.31 (95% CI, 0.21–0.46) for post-treatment PET scans. Regarding the influence of metabolic responses on OS, the pooled HRs for interim and post-treatment PET scans were 0.20 (95% CI, 0.09–0.44) and 0.26 (95% CI, 0.14–0.51), respectively.ConclusionsThe currently available literature suggests that the use of 18F-FDG PET or PET/CT for evaluation of response to NAC provides significant predictive value for disease recurrence and survival in breast cancer patients and might allow risk stratification and guide rational management.

Preoperative imaging for colorectal liver metastases: a nationwide population-based study

BackgroundIn patients with colorectal liver metastases (CRLM) preoperative imaging may include contrast‐enhanced (ce) MRI and [18F]fluorodeoxyglucose (18F‐FDG) PET–CT. This study assessed trends and variation between hospitals and oncological networks in the use of preoperative imaging in the Netherlands.MethodsData for all patients who underwent liver resection for CRLM in the Netherlands between 2014 and 2018 were retrieved from a nationwide auditing database. Multivariable logistic regression analysis was used to assess use of ceMRI, 18F‐FDG PET–CT and combined ceMRI and 18F‐FDG PET–CT, and trends in preoperative imaging and hospital and oncological network variation.ResultsA total of 4510 patients were included, of whom 1562 had ceMRI, 872 had 18F‐FDG PET–CT, and 1293 had combined ceMRI and 18F‐FDG PET–CT. Use of ceMRI increased over time (from 9·6 to 26·2 per cent; P < 0·001), use of 18F‐FDG PET–CT decreased (from 28·6 to 6·0 per cent; P < 0·001), and use of both ceMRI and 18F‐FDG PET–CT 16·9 per cent) remained stable. Unadjusted variation in the use of ceMRI, 18F‐FDG PET–CT, and combined ceMRI and 18F‐FDG PET–CT ranged from 5·6 to 100 per cent between hospitals. After case‐mix correction, hospital and oncological network variation was found for all imaging modalities.DiscussionSignificant variation exists concerning the use of preoperative imaging for CRLM between hospitals and oncological networks in the Netherlands. The use of MRI is increasing, whereas that of 18F‐FDG PET–CT is decreasing.

Однофотонная эмиссионная компьютерная томография в диагностике и мониторинге лимфопролиферативных заболеваний

Despite the high efficiency of the use of 18F-FDG PET in the diagnosis, staging, monitoring and prognosis of treatment of lymphomas, the use of this method in our country is limited due to the high cost and the insufficient number of PET-centers. In this regard, it seems relevant to conduct research aimed at using known and developing original radiopharmaceuticals for lymphoma imaging with single-photon emission computed tomography (SPECT). In this review, the main radiopharmaceuticals (67Ga-citrate, 201Tl, 199Tl, 99mTc-methoxy-isobutyl-isonitrile, 99mTc-tetrofosmin, 111In-octreotide), which are possible for SPECT lymphoma imaging are shown. Also mechanisms of their action, the possibility of their using for various morphological variants of lymphomas and localizations of the lesion are described. In addition, the results of the use of an innovative radiopharmaceutical based on glucose - 99mTc-1-thio-D-glucose, which is promising for diagnostics, staging and monitoring of lymphoproliferative diseases, are presented.

Prognostic factors of postoperative seizure outcome in patients with temporal lobe epilepsy and normal magnetic resonance imaging

To retrospectively analyse a single-centre consecutive surgical series of patients with temporal lobe epilepsy (TLE) and negative MRI. To identify factors associated with postoperative seizure outcome among several presurgical, surgical and postsurgical variables. Clinical records of 866 patients who received temporal lobe resections and with a minimum follow-up of 12months were retrospectively searched for MRI-negative cases. Anamnestic, clinical, neurophysiological, surgical, histopathological and postsurgical data were collected. Seizure outcome was categorised as favourable (Engel's class I) and unfavourable (Engel's classes II-IV). Uni- and multivariate statistical analysis was performed to identify variables having a significant association with seizure outcome. Forty-eight patients matched the inclusion criteria. 26 (54.1%) patients required invasive EEG evaluation with Stereo-electro-encephalography (SEEG) before surgery. Histological evaluation was unremarkable in 34 cases (70.8%), revealed focal cortical dysplasias in 13 cases and hippocampal sclerosis in 2. 28 (58.3%) patients were in Engel's class I after a mean follow-up of 82months (SD ± 74; range 12-252). Multivariate analysis indicated auditory aura, contralateral diffusion of the discharge at Video-EEG monitoring and use of 18F-FDG PET as variables independently associated with seizure outcome. Carefully selected patients with MRI-negative TLE can be good candidates for surgery. Surgery should be considered with caution in patients with clinical features of neocortical seizure onset and contralateral propagation of the discharge. Use of 18F-FDG PET may be helpful to improve SEEG and surgical strategies. The presented data help in optimising the selection of patients with MRI-negative TLE with good chances to benefit from surgery.

18F-FDG PET for Prediction of Conversion to Alzheimer's Disease Dementia in People with Mild Cognitive Impairment: An Updated Systematic Review of Test Accuracy.

Background:A previous Cochrane systematic review concluded there is insufficient evidence to support the routine use of 18F-FDG PET in clinical practice in people with mild cognitive impairment (MCI).Objectives:To update the evidence and reassess the accuracy of 18F-FDG-PET for detecting people with MCI at baseline who would clinically convert to Alzheimer’s disease (AD) dementia at follow-up.Methods:A systematic review including comprehensive search of electronic databases from January 2013 to July 2017, to update original searches (1999 to 2013). All key review steps, including quality assessment using QUADAS 2, were performed independently and blindly by two review authors. Meta-analysis could not be conducted due to heterogeneity across studies.Results:When all included studies were examined across all semi-quantitative and quantitative metrics, exploratory analysis for conversion of MCI to AD dementia (n = 24) showed highly variable accuracy; half the studies failed to meet four or more of the seven sets of QUADAS 2 criteria. Variable accuracy for all metrics was also found across eleven newly included studies published in the last 5 years (range: sensitivity 56–100%, specificity 24–100%). The most consistently high sensitivity and specificity values (approximately ≥80%) were reported for the sc-SPM (single case statistical parametric mapping) metric in 6 out of 8 studies.Conclusion:Systematic and comprehensive assessment of studies of 18FDG-PET for prediction of conversion from MCI to AD dementia reveals many studies have methodological limitations according to Cochrane diagnostic test accuracy gold standards, and shows accuracy remains highly variable, including in the most recent studies. There is some evidence, however, of higher and more consistent accuracy in studies using computer aided metrics, such as sc-SPM, in specialized clinical settings. Robust, methodologically sound prospective longitudinal cohort studies with long (≥5 years) follow-up, larger consecutive samples, and defined baseline threshold(s) are needed to test these promising results. Further evidence of the clinical validity and utility of 18F-FDG PET in people with MCI is needed.

Use of 18F FDG PET and the short temporal response of Hodgkin's disease to RIT.

Radioimmunotherapy (RIT) has been available for some time to treat patients with non-Hodgkin's lymphoma, but its use in Hodgkin's lymphoma has been less available, partly because of the need to find an appropriate antibody. A new radioiodinated chimeric antibody directed against the CD25 epitope (131I basiliximab) seems promising, but assessment of response has been difficult. 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) has become a standard method by which the response of Hodgkin's disease to chemotherapy is both predicted and assessed with well-understood criteria of response. The aim of this study is to determine 18F-FDG-PET can be used to assess response to RIT. Pre- and post-treatment 18F-FDG-PET imaging was performed in a series of 13 patients with advanced Hodgkin's disease who had failed conventional therapy and had been enrolled on a compassionate use program for treatment with 131I basiliximab. The 131I basiliximab was given at an activity of 1200MBq/m2 with one patient receiving 2 cycles and the rest a single cycle. The 18F-FDG-PET studies were compared using the “Deauville” criteria and by comparing the maximum standardized uptake value (SUVmax) of target tumors before and 4 and 8 weeks after treatment. All patients survived long enough for their initial 18F-FDG-PET-computed tomography scan at 4 weeks after their 131I basiliximab therapy. One out of ten patients with “Deauville” Grade 4 or 5 response died during the 6-month follow-up period. Two out of three patients with a “Deauville” Grade 2 or 3 response died in the follow-up period. The mean SUVmax pretreatment was 11.9 (±4.7); at 4-week posttreatment, the mean SUVmax was significantly lower at 6.5 (±5.8) (P = 0.02). At 8 weeks, the mean SUVmax was 8.8 (±7.0), which was not significantly different from the pretreatment level. 18F-FDG-PET imaging is able to predict the short-term response to treatment of Hodgkin's disease by RIT, and an initial poor response appears to predict poor outcome. Early changes in 18F-FDG-PET uptake did not predict sustained response and by 8 weeks all but one patient had recurrent disease.

Retrospective audit of 957 consecutive 18F-FDG PET\u2013CT scans compared to CT and MRI in 493 patients with different histological subtypes of bone and soft tissue sarcoma

BackgroundThe use of 18F-FDG PET–CT (PET–CT) is widespread in many cancer types compared to sarcoma. We report a large retrospective audit of PET–CT in bone and soft tissue sarcoma with varied grade in a single multi-disciplinary centre. We also sought to answer three questions. Firstly, the correlation between sarcoma sub-type and grade with 18FDG SUVmax, secondly, the practical uses of PET–CT in the clinical setting of staging (during initial diagnosis), restaging (new baseline prior to definitive intervention) and treatment response. Finally, we also attempted to evaluate the potential additional benefit of PET–CT over concurrent conventional CT and MRI.MethodsA total of 957 consecutive PET–CT scans were performed in a single supra-regional centre in 493 sarcoma patients (excluding GIST) between 2007 and 2014. We compared, PET–CT SUVmax values in relation to histology and FNCCC grading. We compared PET–CT findings relative to concurrent conventional imaging (MRI and CT) in staging, restaging and treatment responses.ResultsHigh-grade (II/III) bone and soft tissue sarcoma correlated with high SUVmax, especially undifferentiated pleomorphic sarcoma, leiomyosarcoma, translocation induced sarcomas (Ewing, synovial, alveolar rhabdomyosarcoma), de-differentiated liposarcoma and osteosarcoma. Lower SUVmax values were observed in sarcomas of low histological grade (grade I), and in rare subtypes of intermediate grade soft tissue sarcoma (e.g. alveolar soft part sarcoma and solitary fibrous tumour). SUVmax variation was noted in malignant peripheral nerve sheath tumours, compared to the histologically benign plexiform neurofibroma, whereas PET–CT could clearly differentiate low from high-grade chondrosarcoma. We identified added utility of PET–CT in addition to MRI and CT in high-grade sarcoma of bone and soft tissues. An estimated 21% overall potential benefit was observed for PET–CT over CT/MRI, and in particular, in ‘upstaging’ of high-grade disease (from M0 to M1) where an additional 12% of cases were deemed M1 following PET–CT.ConclusionsPET–CT in high-grade bone and soft tissue sarcoma can add significant benefit to routine CT/MRI staging. Further prospective and multi-centre evaluation of PET–CT is warranted to determine the actual predictive value and cost-effectiveness of PET–CT in directing clinical management of clinically complex and heterogeneous high-grade sarcomas.

Diagnostic accuracy of 18F-FDG PET or PET/CT for the characterization of adrenal masses: a systematic review and meta-analysis.

We aimed to explore the role of the diagnostic accuracy of 18F fluodeoxyglucose PET (18F-FDG PET) or PET/CT for characterization of adrenal lesions through a systematic review and meta-analysis. The MEDLINE, EMBASE, and Cochrane Library database, from the earliest available date of indexing through 30 April 2017, were searched for studies evaluating the diagnostic performance of 18F-FDG PET or PET/CT for characterization of adrenal lesions. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR + and LR-), and constructed summary receiver operating characteristic curves. Across 29 studies (2421 patients), the pooled sensitivity for 18F-FDG PET or PET/CT was 0.91 [95% CI (0.88-0.94)] with heterogeneity (χ2 = 141.8, p = 0.00) and a pooled specificity of 0.91 [95% CI (0.87-0.93)] with heterogeneity (χ2 = 113.7, p = 0.00). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 9.9 [95% CI (7.1-13.7)] and negative likelihood ratio (LR-) of 0.09 [95% CI (0.07-0.13)]. The pooled diagnostic odds ratio was 105 [95% CI (63-176)]. In metaregression analysis, study design, publication year, study location (western vs others), interpretation criteria of PET or PET/CT images, quantification of PET or PET/CT [SUVmax (maximum standardized uptake value) vs SUV (standardized uptake value) ratio], patient group, and analysis method (patient-based vs lesion-based) were the sources of the study heterogeneity. However, in multivariate metaregression, no definite variable was the source of the study heterogeneity. 18F-FDG PET or PET/CT demonstrated good sensitivity and specificity for the characterization of adrenal masses. At present, the literature regarding the use of 18F-FDG PET or PET/CT for the characterization of adrenal masses remains still limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of 18F-FDG PET or PET/CT characterization of adrenal masses. Advances in knowledge: 18F- FDG PET or PET/CT showed good sensitivity and specificity for the characterization of adrenal masses and could provide additional information for that purpose.

The Use of 18F-FDG PET in the Diagnostic Workup of Alzheimer's Dementia.

The diagnosis of dementia probably due to Alzheimer's disease is still primarily a clinical one. In cases that remain clinically unclear, however, biomarkers for amyloid deposition and neuronal injury can help to identify the underlying cause. One biomarker even for early neuronal injury in the stage of mild cognitive impairment is cerebral glucose hypometabolism measured by 18F-FDG PET. Distinct patterns of hypometabolism can be seen, for example, in dementia due to Alzheimer's disease, frontotemporal lobar degeneration, and dementia with Lewy bodies. This makes it possible to distinguish between different neurodegenerative diseases as well as major depressive disorder. While the sensitivity of 18F-FDG PET to detect Alzheimer's disease is high, specificity is low and the additional use of biomarkers for amyloid deposition might be beneficial in some cases. In conclusion, 18F-FDG PET is a useful tool when the cause for dementia remains unclear and different diagnosis would lead to different treatment approaches. Due to the lack of treatment options in pre-dementia stages, the use of 18F-FDG PET is currently not recommended for these cases in a purely clinical setting.

Clinical role and accuracy of 18F-FDG PET in evaluating disease activity in patients with chronic inflammatory bowel disease: an updated systematic review and a bivariate meta-analysis

Objective markers of disease activity are crucial for clinical decision making in patients with chronic inflammatory bowel diseases (IBD). We aimed to perform an updated systematic review on the clinical role of 18F-FDG PET in evaluating disease activity in patients with IBD and a bivariate meta-analysis on its accuracy in this setting. A comprehensive computer literature search of studies published through December 2016 about the clinical role of 18F-FDG PET in patients with IBD was performed using the following search algorithm: A) PET OR positron emission tomography OR FDG AND B) inflammatory bowel OR Crohn OR ulcerative colitis OR IBD. All included articles were reviewed. Pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR−) and diagnostic odds ratio (DOR) of 18F-FDG PET in evaluating disease activity in patients with IBD on a per-segment-based analysis were calculated. Furthermore, the summary receiver operating characteristic (sROC) curve has been evaluated. Twenty-three studies on the use of 18F-FDG PET in evaluating disease activity in patients with IBD (584 cases) were discussed in the systematic review. The meta-analysis of nine selected studies provided the following results on a per-segment-based analysis: sensitivity was 85.6% [95% confidence interval (95% CI) 76–92%], specificity 85.5% (95% CI 75–92%), LR+ 5.59 (95% CI 3.29–9.5), LR− 0.15 (95% CI 0.07–0.32), DOR 34.64 (95% CI 13.03–92.08). Heterogeneity among the selected studies was found. 18F-FDG PET demonstrated good accuracy in evaluating the disease activity in patients with IBD and this method could have a clinical impact in patients with IBD. Large multicenter studies and cost-effectiveness analyses are needed to confirm the role of this functional imaging method in this setting.

Use of 18-F FDG PET / CT Scanning Into the First Follow Up of Patients with Multiple Myeloma and Association with Biochemical Response

Use of 18-F FDG PET / CT Scanning Into the First Follow Up of Patients with Multiple Myeloma and Association with Biochemical Response

The use of 18F-FDG PET to differentiate progressive disease from treatment induced necrosis in high grade glioma

In the follow-up of patients treated for high grade glioma, differentiation between progressive disease (PD) and treatment-induced necrosis (TIN) is challenging. The purpose of this study is to evaluate the diagnostic accuracy of FDG PET for the differentiation between TIN and PD after high grade glioma treatment. We retrospectively identified patients between January 2011 and July 2013 that met the following criteria: age >18; glioma grade 3 or 4; treatment with radiotherapy or chemoradiotherapy; new or progressive enhancement on post treatment MRI; FDG PET within 4 weeks of MRI. Absolute and relative (to contralateral white matter) values of SUVmax and SUVpeak were determined in new enhancing lesions on MRI. The outcome of PD or TIN was determined by neurosurgical biopsy/resection, follow-up MRI, or clinical deterioration. The association between FDG PET and outcome was analyzed with univariate logistic regression and ROC analysis for: all lesions, lesions >10, >15, and >20 mm. We included 30 patients (5 grade 3 and 25 grade 4), with 39 enhancing lesions on MRI. Twenty-nine lesions represented PD and 10 TIN. Absolute and relative values of SUVmax and SUVpeak showed no significant differences between PD and TIN. ROC analysis showed highest AUCs for relative SUVpeak in all lesion sizes. Relative SUVpeak for lesions >20 mm showed reasonable discriminative properties [AUC 0.69 (0.41–0.96)]. FDG PET has reasonable discriminative properties for differentiation of PD from TIN in high grade gliomas larger than 20 mm. Overall diagnostic performance is insufficient to guide clinical decision-making.

Use of 18F-FDG PET and MPI with 99mTc-MIBI in a patient with delayed diagnosis of homozygous familial hypercholesterolemia

a Beijing Anzhen Hospital, Capital Medical University, Department of Nuclear Medicine, 2 Anzhen Road, ChaoYang District, Beijing 100029, China b Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vessel Diseases, The Key Laboratory of Remodeling-related Cardiovascular Diseases, Ministry of Education, Department of Atherosclerosis, 2 Anzhen Road, ChaoYang District, Beijing 100029, China

Ultra Staging to Unmask the Prescribing of Adjuvant Therapy in Cancer Patients: The Future Opportunity to Image Micrometastases Using Total-Body 18F-FDG PET Scanning

Ultra Staging to Unmask the Prescribing of Adjuvant Therapy in Cancer Patients: The Future Opportunity to Image Micrometastases Using Total-Body ¹⁸F-FDG PET Scanning

Rôle de la TEP/TDM au 18F-FDG dans la caractérisation des masses surrénaliennes

The adrenal glands contain two functionality different tissues: adrenocortical (cortex) and adrenomedullary (medulla) systems. Each of these tissues may be involved in a benign or malignant neoplastic process. Several approaches may help for tumor tissue characterization. 18F-FDG PET/CT has been evaluated for the diagnosis of non-secreting adrenal masses, in the staging and follow-up of adrenocortical carcinoma (ACC) patients and in the work-up of hereditary pheochromocytomas. This review article aims to guide clinicians towards the appropriate use of 18F-FDG PET in relation to the clinical context and to assist nuclear medicine practitioners in interpreting the results.

Assessment of immature teratoma by 18F-FDG PET/CT

Teratomas are the most frequent extra-gonadal non-seminomatous germ cell tumors (NSGCTs). Retroperitoneum is the third most common site for teratomas and 30–40% of them may have immature tissue. The use of 18F-FDG PET in NSGCTs has been recently investigated. Here we report a 22 year-old male patient with metastatic immature teratoma, followed by PET/CT according to the existence of 18F-FDG avid metastatic lesions. According to our experience, functional imaging with PET/CT has an additive effect to anatomical imaging modalities in NSGCT patients when the tumoral tissue contains more primitive immature elements.

Use of 18FFDG-PET in patients with suspicion of recurrent differentiated thyroid cancer by elevated antithyroglobulin antibodies levels and negative 131I scan

Aim To evaluate the utility of 18FFDG-PET for patients diagnosed of differentiated thyroid carcinoma who present risk of disease and invaluable levels of thyroglobulin (Tg) by the presence of antibodies antithyroglobulin (AbTg). Material and methods Retrospective study of 7 women of 40 years old and histological diagnosis of differentiated thyroid cancer (7 papillary tumours) that were sent to our department for the accomplishment of 18FFDG-PET study because of suspicion of disease, due to 131I negative and high levels of AbTg, between the year 2002 and 2007. 11 PET scans were obtained after the intravenous injection of 370–434 MBq of 18FFDG in normoglycemia conditions and previous administration of muscle relaxant, hydration and diuretic. The results of 18FFDG-PET scans were confirmed by pathologic examination or clinical outcome and radiographic examination for more than 24 months. Results The prevalence of recurrence in our population was 57.14%. All patients presented levels of Tg lower than 3 ng/dl and AbTg superior to 200 UI/ml. Three patients had precedent thyroiditis. Out of 11 scans performed 3 of them were negative and 8 cases were found positive. It ruled out the existence of disease in three patients and localized the presence of recurrence in 4 patients. Conclusion 18F-FDG-PET is a useful diagnostic tool for the detection of recurrence as well as to rule out the existence of disease with a high accuracy, in patients with differentiated thyroid carcinoma with 131 I whole body scan negative but with pathological elevation of antithyroglobulin antibodies.