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Simple Summary: Among head–neck tumors, squamous cell carcinoma is the most frequent histotype and includes a range of malignancies with different sites of origin as well as different therapeutic strategies and clinical outcomes. In daily practice, patients with head–neck squamous cell carcinoma are seen in various clinical settings, requiring a multidisciplinary approach to therapeutic decisions and clinical care. 18F-FDG PET/CT plays a well-defined role in the management of these tumors for pre-treatment staging and radiotherapy planning as well as treatment-response assessment and post-therapy follow-up. This paper is an overview of the standard use of 18F-FDG PET/CT in the various clinical scenarios of head–neck squamous cell carcinoma. Also, emerging applications will be reviewed, including the use of radiopharmaceuticals other than 18F-FDG, PET/MRI implementation in clinical practice, and the use of radiomics and machine learning. This article provides an overview of the use of 18F-FDG PET/CT in various clinical scenarios of head–neck squamous cell carcinoma, ranging from initial staging to treatment-response assessment, and post-therapy follow-up, with a focus on the current evidence, debated issues, and innovative applications. Methodological aspects and the most frequent pitfalls in head–neck imaging interpretation are described. In the initial work-up, 18F-FDG PET/CT is recommended in patients with metastatic cervical lymphadenectomy and occult primary tumor; moreover, it is a well-established imaging tool for detecting cervical nodal involvement, distant metastases, and synchronous primary tumors. Various 18F-FDG pre-treatment parameters show prognostic value in terms of disease progression and overall survival. In this scenario, an emerging role is played by radiomics and machine learning. For radiation-treatment planning, 18F-FDG PET/CT provides an accurate delineation of target volumes and treatment adaptation. Due to its high negative predictive value, 18F-FDG PET/CT, performed at least 12 weeks after the completion of chemoradiotherapy, can prevent unnecessary neck dissections. In addition to radiomics and machine learning, emerging applications include PET/MRI, which combines the high soft-tissue contrast of MRI with the metabolic information of PET, and the use of PET radiopharmaceuticals other than 18F-FDG, which can answer specific clinical needs. [ABSTRACT FROM AUTHOR]

Purpose : To investigate whether the COVID-19 pandemic and national lockdown had an impact on the extent of cancer disease at FDG PET/CT staging as surrogate marker. Methods: Retrospective observational study including cancer patients submitted to FDG PET/CT staging from June 1 to October 31, 2020, and June 1 to October 31, 2019, respectively. Data regarding primary tumour, nodal (N) status and number of involved nodal stations, and presence and number of distant metastases (M) were collected. Each scan was classified in limited vs advanced status. Data were aggregated across the study population and tumour type. Bi-weekly frequencies of the observed events were analysed. Results: Six hundred eleven patients were included (240 in 2019 vs 371 in 2020, respectively). A significant increase of advanced disease patients (rate 1.56, P < 0.001), N + or M + patients (rate 1.84 and 2.09, respectively, P < 0.001), and patients with a greater number of involved N stations or M (rate 2.01 and 2.06, respectively, P < 0.001) were found in 2020 compared with data of 2019. Analysis by tumour type showed a significant increase of advanced disease in lymphoma and lung cancer in 2020 compared with 2019 (P < 0.001). In addition, a significant increase of nodal involvement was found in lung, gastro-intestinal, and breast cancers, as well as in lymphoma patients (P < 0.02). A significant increase of distant metastases was found in lung cancers (P = 0.002). Conclusion: Cancer patients with advanced disease at FDG PET/CT staging increased in 2020 compared with 2019, following the national lockdown due to the COVID-19 pandemic, 1.5-fold with a significant increase of patients with N or M involvement. Targeted health interventions are needed to mitigate the effects of the pandemic on patient outcome. [ABSTRACT FROM AUTHOR]

Aim: The first prototype of the "Multidisciplinary Tumor Board Smart Virtual Assistant" is presented, aimed to (i) Automated classification of clinical stage starting from different free-text diagnostic reports; (ii) Resolution of inconsistencies by identifying controversial cases drawing the clinician's attention to particular cases worthy for multi-disciplinary discussion; (iii) Support environment for education and knowledge transfer to junior staff; (iv) Integrated data-driven decision making and standardized language and interpretation. Patients and Method: Data from patients affected by Locally Advanced Cervical Cancer (LACC), FIGO stage IB2-IVa, treated between 2015 and 2018 were extracted. Magnetic Resonance (MR), Gynecologic examination under general anesthesia (EAU), and Positron Emission Tomography–Computed Tomography (PET-CT) performed at the time of diagnosis were the items from the Electronic Health Records (eHRs) considered for analysis. An automated extraction of eHR that capture the patient's data before the diagnosis and then, through Natural Language Processing (NLP), analysis and categorization of all data to transform source information into structured data has been performed. Results: In the first round, the system has been used to retrieve all the eHR for the 96 patients with LACC. The system has been able to classify all patients belonging to the training set and - through the NLP procedures - the clinical features were analyzed and classified for each patient. A second important result was the setup of a predictive model to evaluate the patient's staging (accuracy of 94%). Lastly, we created a user-oriented operational tool targeting the MTB who are confronted with the challenge of large volumes of patients to be diagnosed in the most accurate way. Conclusion: This is the first proof of concept concerning the possibility of creating a smart virtual assistant for the MTB. A significant benefit could come from the integration of these automated methods in the collaborative, crucial decision stages. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the role of apparent diffusion coefficient (ADC) value measurement in the diagnosis of metastatic lymph nodes (LNs) in patients with locally advanced cervical cancer (LACC) and to present a systematic review of the literature. Material and methods: Magnetic resonance imaging (MRI) exams of patients with LACC were retrospectively evaluated. Mean ADC, relative ADC (rADC), and correct ADC (cADC) values of enlarged LNs were measured and compared between positron emission tomography (PET)-positive and PET-negative LNs. Comparisons were made using the Mann-Whitney U-test and Student’s t-test. ROC curves were generated for each parameter to identify the optimal cut-off value for differentiation of the LNs. A systematic search in the literature was performed, exploring several databases, including PubMed, Scopus, the Cochrane library, and Embase. Results: A total of 105 LNs in 34 patients were analysed. The median ADC value of PET-positive LNs (0.907 × 10-3 mm²/s [0.780-1.080]) was lower than that in PET-negative LNs (1.275 × 10-3 mm²/s [1.063-1.525]) (p < 0.05). rADC and cADC values were lower in PET-positive LNs (rADC: 0.120 × 10-3 mm²/s [–0.060-0.270]; cADC: 1.130 [0.980-1.420]) than in PET-negative LNs (rADC: 0.435 × 10-3 mm²/s [0.225-0.673]; cADC: 1.615 [1.210-1.993]) LNs (p < 0.05). ADC showed the highest area under the curve (AUC 0.808). Conclusions: Mean ADC, rADC, and cADC were significantly lower in the PET-positive group than in the PET-negative group. The ADC cut-off value of 1.149 × 10-3 mm²/s showed the highest sensitivity. These results confirm the usefulness of ADC in differentiating metastatic from non-metastatic LNs in LACC. [ABSTRACT FROM AUTHOR]

A correction is presented to the article "European Journal of Nuclear Medicine and Molecular Imaging" which appeared in the 14 June 2022 issue.

Early response evaluation with [18F]fluordeoxyglucose ( FDG) positron emission tomography after 2 cycles of chemotherapy (interim PET) has been indicated as the strongest predictor for outcome in classical Hodgkin lymphoma ( HL). We studied the prognostic role of the number of tumor-infiltrating CD68+ cells and of the plasma levels of TARC (thymus and activation-regulated chemokine) in the context of interim PET in 102 patients with classical HL treated with Adriamycin, Bleomycin, Vinblastine, Dacarbazine ( ABVD). After 2 ABVD cycles, interim PET according to Deauville criteria was negative (score 0-3) in 85 patients and positive (score 4-5) in 15 patients (2 patients technically not evaluable). TARC levels were elevated in 89% of patients at diagnosis, and decreased after 2 cycles in 82% of patients. Persistently elevated TARC levels in 18% of patients were significantly associated with a positive PET result ( P = 0.007). Strong predictors for progression-free survival ( PFS) were a negative interim PET (85% vs. 28%, P < 0.0001) and CD68+ cell counts <5% (89% vs. 67%, P = 0.006), while TARC levels at diagnosis and at interim evaluation had no prognostic role. In multivariate analysis, interim PET, CD68+ cell counts and presence of B-symptoms were independently associated with PFS. We conclude that although TARC levels are a biomarker for early response evaluation, they cannot substitute for interim PET as outcome predictor in HL. The evaluation of CD68 counts and B-symptoms at diagnosis may help to identify low-risk patients regardless positive interim PET. [ABSTRACT FROM AUTHOR]

In recent years, 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) has emerged as an important tool for the postoperative management of patients with differentiated thyroid cancer (DTC) and it is widely used in selected clinical situations. The most valuable role that FDG-PET/CT plays in clinical practice is that it can be used to obtain prognostic information in patients with increasing thyroglobulin (Tg) levels and negative 131I whole-body scan post-thyroidectomy and radioiodine (RAI) ablation. FDG-PET/CT may also have a potential role in the initial staging and follow-up of high-risk patients with aggressive histological subtypes, in the identification of patients who are at the highest risk of disease-specific mortality, in the management of patients with RAI-refractory disease, in clinical trials of novel targeted therapies in patients with advanced metastatic disease, and in the evaluation of thyroid nodules with indeterminate fine-needle aspiration for cytology. However, several controversies remain to be resolved, namely: the cutoff value of Tg in the selection of DTC patients for FDG-PET/CT, whether FDG-PET/CT scanning should be performed under thyrotropin stimulation or suppression, and the clinical significance of thyroid FDG-PET/CT incidentalomas. The aim of the present article is to provide an overview of the data about the molecular basis for, clinical indications of, and controversies related to the use of FDG-PET/CT in patients with DTC. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate whether standardized uptake value (SUV) and/or metabolic rate of glucose (MRglu) are different among epithelioid, mixed, and spindle cell uveal melanomas, as well as between low and high risk melanomas; to correlate ultrasonographic data and metabolic parameters with histopathological features; and to assess the role of F-FDG PET/CT for evaluating prognosis. Methods: Of 34 eligible patients prospectively enrolled with clinical suspicion of medium/large uveal melanoma, 26 (15 men, mean age 62.8 ± 11.8 years) were evaluated. All patients underwent metastatic work-up, 3-D dynamic brain and whole-body F-FDG PET/CT, and surgery. Results: Of the 26 ocular lesions, 23 showed F-FDG uptake, with a sensitivity of 88 %. MRglu was significantly higher in the epithelioid cell melanomas than in the spindle cell melanomas, as well as in high-risk lesions than in low-risk lesions ( p = 0.01, p = 0.02, respectively). SUV and MRglu were correlated with histopathological features while ultrasonographic data were not. Conclusion: MRglu is useful for distinguishing the different cell types in uveal melanoma, as well as high-risk from low-risk lesions, while SUV is not. MRglu provides a more accurate evaluation of glucose consumption, whereas SUV provides only an estimation. In addition, the metabolic parameters correlate with histopathological features, well also reflecting cellular behaviour in ocular malignancy. A longer follow-up is needed to assess the role of F-FDG in evaluating prognosis. [ABSTRACT FROM AUTHOR]

Endocrine pancreatic tumors (EPTs) are a heterogeneous group of neoplasms with variable clinical and biological features and prognosis, ranging from very slow-growing tumors to highly aggressive and very malignant ones. As other neuroendocrine tumors, EPTs are characterized by the presence of neuroamine uptake mechanisms and/or peptide receptors at the cell membrane and these features constitute the basis of the clinical use of specific radiolabeled ligands, both for imaging and therapy. The more widespread use of hybrid machines, i.e., positron emission tomography/computed tomography (PET/CT), allows to perform imaging with high resolution and high diagnostic accuracy especially for small lesions, and to correlate anatomic location with function. The recent WHO recommendations for classification and prognostic factors help the selection of tracers likely to show a positive image on PET; therefore, tracers exploiting specific metabolic patterns (F-DOPA and C-5-HTP) or specific receptor expression (Ga-DOTA-peptides) are suited to well-differentiated tumors, while the use of F-FDG is preferred for poorly-differentiated neoplasms with high proliferative activity and loss of neuroendocrine features. In differentiated EPTs, C-5-HTP performs better than F-DOPA even though its use is hampered by its complex production and limited availability and experience; Ga-peptides are indicated for all type of gastroenteropancreatic (GEP) neuroendocrine tumors, regardless of their functional activity. In addition, Ga-DOTA-peptides play a distinctive role in planning peptide receptor radionuclide therapy. [ABSTRACT FROM AUTHOR]

The assessment of hepatobiliary and pancreatic tumors is commonly achieved by ultrasound, computed tomography (CT), and magnetic resonance. The 2-[fluorine-18]fluoro-2-deoxy- d-glucose (FDG) positron emission tomography (PET) detects increased glucose metabolism associated with neoplastic lesions, provides high accuracy in most cancer imaging applications and is now widely used in clinical practice. However, PET is not always useful and accurate knowledge of appropriate indications is essential for a proper clinical management. F-FDG is transported into cells and phosphorylated by the enzyme hexokinase to F-FDG-6-phosphate, which cannot proceed down the glycolytic pathway and therefore is accumulated in the malignant tissue. PET allows accurate quantification of FDG uptake in tissue, and previous studies have demonstrated that standardized uptake values provide highly reproducible parameters of tumor glucose use (Weber et al., J Nucl Med 40:1771-1777, ). The recent development and diffusion of hybrid PET-CT scanners allows functional and anatomic data to be obtained in a single examination, improving lesion localization and resulting in significant diagnostic improvement (Wahl, J Nucl Med 45:82S-95S, ). Moreover, CT can be performed diagnostically with the use of intravenous and oral contrast and simultaneous PET-contrast-enhanced CT scanning appears to be an efficient method in cancer evaluation. However, in most centers, a low-dose CT is routinely performed without contrast media infusion. Proper patient preparation, scanning protocol, combined assessment of PET and CT data, and the evaluation of conventional imaging findings are essential to define disease and to avoid diagnostic pitfalls. The role of PET and PET-CT in malignancies of the liver, biliary tract, and pancreas is here reviewed; normal patterns, representative cases, and common pitfalls are also presented. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: The aim of this study was to perform a meta-analysis of published data about the diagnostic performance of 18F-dihydroxyphenylalanine (DOPA) positron emission tomography (PET) or PET/computed tomography (CT) in detecting recurrent medullary thyroid carcinoma (MTC). Materials and Methods: A comprehensive literature search of studies indexed in the PubMed/MEDLINE, Scopus, and Embase databases through January 2012 and regarding 18F-DOPA PET or PET/CT in patients with suspected recurrent MTC was carried out. Pooled detection rates (DR) in per patient and per lesion analyses were calculated. A subanalysis considering serum levels of calcitonin and carcinoembryonic antigen, device used, and carbidopa pretreatment was also performed. Results: Eight studies including 146 patients with suspected recurrent MTC were included. The DRs of 18F-DOPA PET and PET/CT in per patient and per lesion analyses were 66% and 71%, respectively. DRs significantly increased in patients with serum calcitonin ≥1000 ng/L (86%) and calcitonin doubling times <24 months (86%). Conclusions: Fluorine-18-DOPA PET and PET/CT may be useful functional imaging methods in detecting recurrent MTC. The DR of recurrent MTC using these imaging methods increases in patients with higher calcitonin levels and lower calcitonin doubling times. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to systematically review and conduct a meta-analysis of published data about the diagnostic performance of F-dihydroxyphenylalanine (DOPA) positron emission tomography (PET) in patients with paraganglioma (PG). Methods: A comprehensive computer literature search of studies published through 30 June 2011 regarding F-DOPA PET or PET/computed tomography (PET/CT) in patients with PG was performed in PubMed/MEDLINE, Embase and Scopus databases. Pooled sensitivity and specificity of F-DOPA PET or PET/CT in patients with PG on a per patient- and on a per lesion-based analysis were calculated. The area under the receiver-operating characteristic (ROC) curve was calculated to measure the accuracy of F-DOPA PET or PET/CT in patients with PG. Furthermore, a sub-analysis taking into account the different genetic mutations in PG patients was also performed. Results: Eleven studies comprising 275 patients with suspected PG were included in this meta-analysis. The pooled sensitivity of F-DOPA PET and PET/CT in detecting PG was 91% [95% confidence interval (CI) 87-94%] on a per patient-based analysis and 79% (95% CI 76-81%) on a per lesion-based analysis. The pooled specificity of F-DOPA PET and PET/CT in detecting PG was 95% (95% CI 86-99%) on a per patient-based analysis and 95% (95% CI 84-99%) on a per lesion-based analysis. The area under the ROC curve was 0.95 on a per patient- and 0.94 on a per lesion-based analysis. Heterogeneity between the studies about sensitivity of F-DOPA PET or PET/CT was found. A significant increase in sensitivity of F-DOPA PET or PET/CT was observed when a sub-analysis excluding patients with succinate dehydrogenase subunit B (SDHB) gene mutations was performed. Conclusion: In patients with suspected PG F-DOPA PET or PET/CT demonstrated high sensitivity and specificity. F-DOPA PET or PET/CT are accurate methods in this setting. Nevertheless, possible sources of false-negative results should be kept in mind. Furthermore, SDHB gene mutations could influence F-DOPA PET or PET/CT diagnostic performance. [ABSTRACT FROM AUTHOR]

Purpose: To retrospectively evaluate and compare F-FDG, F-DOPA and Ga-somatostatin analogues for PET/CT in patients with residual/recurrent medullary thyroid carcinoma (MTC) suspected on the basis of elevated serum calcitonin levels. Methods: Included in the study were 18 patients with recurrent MTC in whom functional imaging with the three tracers was performed. The PET/CT results were compared on a per-patient basis and on a per-lesion-basis. Results: At least one focus of abnormal uptake was observed on PET/CT in 13 patients with F-DOPA (72.2% sensitivity), in 6 patients with Ga-somatostatin analogues (33.3%) and in 3 patients with F-FDG (16.7%) ( p < 0.01). There was a statistically significant difference in sensitivity between F-DOPA and F-FDG PET/CT ( p < 0.01) and between F-DOPA and Ga-somatostatin analogue PET/CT ( p = 0.04). Overall, 72 lesions were identified on PET/CT with the three tracers. F-DOPA PET/CT detected 85% of lesions (61 of 72), Ga-somatostatin analogue PET/CT 20% (14 of 72) and F-FDG PET/CT 28% (20 of 72). There was a statistically significant difference in the number of lymph node, liver and bone lesions detected with the three tracers ( p < 0.01). In particular, post-hoc tests showed a significant difference in the number of lymph node, liver and bone lesions detected by F-DOPA PET/CT and F-FDG PET/CT ( p < 0.01 for all the analyses) and by F-DOPA PET/CT and Ga-somatostatin analogue PET/CT ( p < 0.01 for all the analyses). The PET/CT results led to a change in management of eight patients (44%). Conclusion: F-DOPA PET/CT seems to be the most useful imaging method for detecting recurrent MTC lesions in patients with elevated serum calcitonin levels, performing better than F-FDG and Ga-somatostatin analogue PET/CT. F-FDG may complement F-DOPA in patients with an aggressive tumour. [ABSTRACT FROM AUTHOR]

BACKGROUND: The goal of this study was to prospectively analyze the diagnostic performances of magnetic resonance imaging (MRI) and positron emission tomography (PET)/computed tomography (CT) in predicting pathologically assessed residual disease in a large, single-institution series of locally advanced cervical cancer (LACC) patients triaged to neoadjuvant treatments followed by radical surgery. METHODS: Between April 2007 and March 2010, 96 patients with histologically documented cervical cancer (any histology) and FIGO stage IB2-IVA were enrolled. MRI and PET/CT were recommended to be performed within 4-6 weeks from the end of treatment, and histology was the reference standard. Sensitivity, specificity, and accuracy were compared using the McNemar test. RESULTS: For residual disease in the cervix, sensitivity was higher for MRI than for PET/CT (86.1% vs 63.1%; P = .002), while specificity was significantly higher for PET/CT compared with MRI ( P = .002). There was no difference in accuracy values between the 2 imaging modalities. For MRI analysis of lymph node groups, sensitivity, specificity, and accuracy were 35.7%, 95.9%, and 88.0%, respectively. Conversely, sensitivity, specificity, and accuracy for PET/CT were 28.6%, 97.8%, and 88.7%, respectively. Absence of follicular structures replaced by prevalent sclerosis and/or sinus histiocytosis was the most frequently documented morphological pattern in false-positive cases. CONCLUSION: Neither MRI nor PET/CT accurately detected residual disease in LACC patients triaged to radical surgery after neoadjuvant treatment, disallowing the option of avoiding or modulating completion surgery. Cancer 2011;. © 2011 American Cancer Society. [ABSTRACT FROM AUTHOR]

Purpose. To perform an overview about the role of positron emission tomography (PET) or PET/computed tomography (PET/CT) using different radiopharmaceuticals in recurrent medullary thyroid carcinoma (MTC) based on biochemical findings (increased tumor marker levels after primary surgery). Methods. A comprehensive literature search of studies published in PubMed/MEDLINE, Scopus, and Embase databases through February 2012 regarding PET or PET/CT in patients with recurrent MTC was performed. Results. Twenty-nine studies comprising 714 patients with suspected recurrent MTC were retrieved. Twentyseven articles evaluated the role of fluorine-18-fluorodeoxyglucose (FDG) PET or PET/CT in recurrent MTC with conflicting results. Diagnostic accuracy of FDG-PET and PET/CT increased in MTC patients with higher calcitonin and carcinoembryonic antigen values, suggesting that these imaging methods could be very useful in patients with more advanced and aggressive disease. Eight articles evaluated the role of fluorine-18-dihydroxyphenylalanine (FDOPA) PET or PET/CT in recurrent MTC reporting promising results. Overall, FDOPA seems to be superior but complementary compared to FDG in detecting recurrent MTC. Few studies evaluating other PET tracers are also discussed. Conclusions. PET radiopharmaceuticals reflect differentmetabolic pathways in MTC. FDOPA seems to be the most useful PET tracer in detecting recurrentMTC based on rising levels of tumor markers. FDG may complement FDOPA in patients with more aggressive MTC. [ABSTRACT FROM AUTHOR]

Background: 18F-fluoro-deoxy-glucose (18F-FDG) positron emission tomography integrated/combined with computed tomography (PET-CT) provides the best diagnostic results in the metabolic characterization of undetermined solid pulmonary nodules. The diagnostic performance of 18F-FDG is similar for nodules measuring at least 1 cm and for larger masses, but few data exist for nodules smaller than 1 cm. Case presentation: We report five cases of oncologic patients showing focal lung 18F-FDG uptake on PET-CT in nodules smaller than 1 cm. We also discuss the most common causes of 18F-FDG false-positive and false-negative results in the pulmonary parenchyma. In patient 1, contrast-enhanced CT performed 10 days before PET-CT did not show any abnormality in the site of uptake; in patient 2, high-resolution CT performed 1 month after PET showed a bronchiole filled with dense material interpreted as a mucoid impaction; in patient 3, contrast-enhanced CT performed 15 days before PET-CT did not identify any nodules; in patients 4 and 5, contrast-enhanced CT revealed a nodule smaller than 1 cm which could not be characterized. The 18F-FDG uptake at follow-up confirmed the malignant nature of pulmonary nodules smaller than 1 cm which were undetectable, misinterpreted, not recognized or undetermined at contrast-enhanced CT. Conclusion: In all five oncologic patients, 18F-FDG was able to metabolically characterize as malignant those nodules smaller than 1 cm, underlining that: 18F-FDG uptake is not only a function of tumor size but it is strongly related to the tumor biology; functional alterations may precede morphologic abnormalities. In the oncologic population, especially in higher-risk patients, PET can be performed even when the nodules are smaller than 1 cm, because it might give an earlier characterization and, sometimes, could guide in the identification of alterations missed on CT. [ABSTRACT FROM AUTHOR]

The utilization of 2-[fluorine 18] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) in combination with computed tomography (CT) in the assessment of gynecologic malignancies has been rapidly growing in recent years; however, its role in clinical practice has yet to be established. A number of pitfalls are commonly encountered, including normal physiologic activity in bowel loops and blood vessels, or focal retained activity in ureters and urinary bladder. Increased uptake has also been reported in many benign pelvic processes and in premenopausal patients; endometrial activity changes cyclically, whereas increased ovarian uptake may be functional. FDG PET-CT has an emerging role in staging nodal disease and in the evaluation of local recurrence or peritoneal spread of gynecologic malignancies and is also useful in monitoring response to therapy and in long-term follow-up. FDG PET-CT is most suitable in patients with high tumor markers and negative or uncertain conventional imaging data. Patient preparation, proper scanning protocol, combined assessment of PET and CT data, and the evaluation of conventional imaging findings are essential to define disease and to avoid diagnostic pitfalls. [ABSTRACT FROM AUTHOR]

Early diagnosis of peritoneal spread in malignant disease is essential to prevent unnecessary laparotomies and to select the patients in whom complete cytoreduction is feasible. Although anatomic imaging is the mainstay for evaluating peritoneal seeding, small neoplastic implants can be difficult to detect with CT and MR imaging. FDG PET-CT has the potential to improve detection of peritoneal metastases as lesion conspicuity is high at PET due to low background activity and fused PET-CT offers the combined benefits of anatomic and functional imaging. Correlation of uptake modalities with the pathogenesis of intraperitoneal spread of malignancies, provides a rational system of analysis and is essential to define disease. Distinct patterns appear to predict the presence of either nodular or diffuse peritoneal pathology. Main pitfalls are related to normal physiologic activity in bowel loops and blood vessels or focal retained activity in ureters and urinary bladder. PET-CT is most suitable in patients with high tumor markers and negative or uncertain conventional imaging data and in selecting patients for complete cytoreduction. FDG PET-CT adds to conventional imaging in the detection and staging of peritoneal carcinomatosis and is a useful diagnostic tool in monitoring response to therapy and in long term follow-up. [ABSTRACT FROM AUTHOR]

Background: Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin tumor. Currently, 18F-fluoro-deoxy-glucose (18F-FDG) PET/CT is the functional imaging modality of choice. Few data are available on the use of 68Ga-somatostatin analogs. The aim of our study was to evaluate and compare the diagnostic performance of 18F-FDG and 68Ga-somatostatin analog PET/CT in MCC patients.Results: Fifteen patients (12 males, 3 females; median age 73 years; range 41-81 years) with histologically proven MCC (4 with unknown primary lesion) who underwent both 18F-FDG and 68Ga-somatostatin analog PET/CT for staging, re-staging, or treatment response assessment were retrospectively evaluated. Results of both studies were qualitatively analyzed and compared on a patient- and lesion-based analysis, using histology or clinical/radiological follow-up as reference standard for final diagnosis. According to final diagnosis, 8/15 patients had at least one MCC lesion and 7/15 had no evidence of disease. On a patient-based analysis, 18F-FDG and 68Ga-somatostatin analogs correctly classified as positive 8/8 (100% sensitivity) patients and as negative 6/7 (85.7% specificity) and 5/7 (71.4% specificity) patients, respectively, with no significant difference. On a lesion-based analysis, 18F-FDG detected 67/75 lesions (89%) and 68Ga-somatostatin analogs 69/75 (92%), with no significant difference. In four patients with unknown primary MCC, both tracers failed to identify the primary MCC site.Conclusions: Our preliminary data suggest that 18F-FDG and 68Ga-somatostatin analog PET/CT provide good and equivalent diagnostic performance, adding interesting insights into the complex MCC biology. However, these results do not suggest that 18F-FDG PET/CT should be replaced by 68Ga-somatostatin receptor imaging, which should be performed in addition, according to clinical indication, to the perspective of “personalized medicine.” [ABSTRACT FROM AUTHOR]

Study Design. Retrospective study. Objective. To evaluate, in a pediatric population, 18F-Fluorodeoxy- glucose (18F-FDG) metabolic activity of normal spinal cord and to assess the correlation with demographic, clinical, and environmental variables. Summary of Background Data. 18F-FDG uptake of normal spinal cord is variable in children. The knowledge of physiological metabolism of spinal cord is essential to distinguish normal from pathological findings by positron emission tomography–computed tomography (PET-CT). Methods. We retrospectively evaluated 18F-FDG positron emission tomography–computed tomography scans from a total of 167 pediatric patients (97 males; 3.9–18.9 yr) divided into 4 age groups (0–4.9 yr, 5–9.9 yr, 10–14.9 yr, and 15–18.9 yr), excluding those submitted to previous or recent therapeutic procedures influencing spinal cord metabolism or with central nervous system diseases. Spinal cord was divided into 3 levels (C1–C7; D1–D6; and D7–L1), and maximum standardized uptake value (SUVmax) of each cord level was measured. Correlations between SUVmax and spinal cord level, age, body weight, sex, type of disease, and season were statistically assessed. Results. Median SUVmax was similar and significantly ( P < 0.01) higher at C1–C7 and D7–L1 levels than at D1–D6 level and it significantly ( P < 0.01) increased with age in all spinal cord levels. A positive and significant association between SUVmax and body weight, female sex, and Hodgkin lymphoma was found. No significant association with season was observed. By multivariate analysis, only weight and female sex remained significant. Conclusion. Knowledge of physiological 18F-FDG spinal cord activity in children is essential for a correct interpretation of positron emission tomography–computed tomography, especially in oncologic pediatric patients to avoid potential pitfalls. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To systematically review the role of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) in evaluating treatment response to imatinib or other drugs in gastrointestinal stromal tumors (GIST). Methods: A comprehensive literature search of published studies through February 2011 in PubMed/MEDLINE and EMBASE databases was performed. Results: We identified 19 studies including 628 patients with GIST. Main findings of included studies are presented. Conclusions: 18F-FDG PET has a significant value in assessing treatment response to imatinib or other drugs in GIST patients. 18F-FDG PET allows an early assessment of treatment response and is a strong predictor of clinical outcome. [Copyright &y& Elsevier]