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Purpose: The management of differentiated thyroid cancer (DTC) is actually based on a dynamic risk stratification based on classes of response to the therapy. Indeterminate response (IR) includes a heterogeneous group of patients with different characteristics, particularly different Tg and AbTg levels and/or imaging findings. The aim of systematic review (SR) is to evaluate the prognosis, diagnostic findings and other characteristics of patients in the IR class. Methods: A wide literature search in the Scopus, PubMed/MEDLINE and Web of Science databases was performed to find published articles on patients with DTC and IR after treatment. The quality assessment of studies was carried out using QUADAS-2 evaluation. Results: Eight articles were included in the systematic review. Six studies evaluated the prognosis and the prognostic factor in patients with IR, one study evaluated the role of 2-[18F]FDG PET-CT in the management of patients with IR and biochemical incomplete response and one study the risk factors for IR. Conclusion: Patients with DTC and IR to therapy have a probability of disease relapse < 15%. Tg value could be a predictor of disease progression. The role of 2-[18F]FDG PET-CT needs to be further investigated.

Purpose: This updated systematic review and bivariate meta-analysis aimed to investigate the diagnostic performance of 2-[18F]FDG PET/CT for the detection of recurrent disease in patients with differentiated thyroid cancer (DTC) who have negative 131I whole body scintigraphy and increased antithyroglobulin antibodies (TgAb) levels. Methods: The current systematic review was carried out following a preset protocol, and the “Preferred Reporting Items for a Systematic Review and Meta-Analysis” served as a guideline for its development and reporting. A comprehensive research of the PubMed/MEDLINE, Embase and Cochrane library databases was conducted until June 2024. Results: Between 2002 and 2023, 13 studies (608 patients) published on this topic were selected. The pooled sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 2-[18F]FDG PET or PET/CT were 84% (95%CI: 78−87%), 82% (95%CI: 78−86%), 72% (95%CI: 67−76%), 90% (95%CI: 87−93%) and 83% (95%CI: 79%-86%) respectively. The pooled positive and negative likelihood ratios (LR+ and LR − ) and the diagnostic odds ratio (DOR) were 0.180 (95%CI: 0.128–0.253), 3.214 (95%CI: 2.357–4.383), and 17.863 (95%CI: 10.475–30.462), respectively. No statistically significant heterogeneity among the studies was found for all the metrics evaluated (I2< 50%). Conclusions: 2-[18F]FDG PET/CT demonstrated a good diagnostic performance in patients with DTC and increased TgAb. Although more studies are warranted, the provided evidence-based data should support the integration of 2-[18F]FDG PET/CT in clinical and diagnostic guidelines on DTC patients with increased TgAb.

Purpose: The incidence and clinical significance of thyroiditis detected by molecular imaging methods is a clinical challenge that is not widely investigated in the literature. The aim of this systematic review was to analyze published data about the detection of thyroiditis on PET or PET/CT using different tracers. Methods: A comprehensive computer literature search of the Scopus, PubMed/MEDLINE, Embase, and Cochrane library databases was conducted up to November 2019 to find relevant papers on the detection of thyroiditis by PET/CT, the metabolic appearance, and the clinical significance. Results: Twenty-six articles were selected and retrieved in full-text version. From the analyses of these studies, the following main findings have been found. Diffuse thyroid uptake of PET tracers is a relatively frequent event, ranging from 0.4 to 46.2%, and it is commonly related to benign disease. Thyroiditis is the most frequent reason for diffuse increased thyroid 18F-FDG uptake. Cases of malignant disease with a pattern of diffuse 18F-FDG thyroid uptake are less frequent. Preliminary studies show a possible role of thyroiditis detected by 18F-FDG PET/CT in evaluating treatment response and as a prognostic marker in oncological patients treated with immunotherapy. However, further studies are needed. Conclusions: Diffuse 18F-FDG thyroid uptake is a relatively rare event commonly due to benign diseases, among which thyroiditis is the most common. The rate of neoplastic disease with diffuse 18F-FDG thyroid uptake is very low. Diffuse 18F-FDG thyroid uptake requires further investigation and clinical evaluation for the correct diagnosis. Currently, cases of diffuse thyroid uptake with non-18F-FDG radiotracer are only anecdotal.

The form of a building is among the most critical design aspects concerning building energy consumption. Form-based passive design strategies, like solar control, can significantly reduce heating and cooling demands if implemented early in the design process. In this sense, there is an evident need for tools that can adequately support designers in their decisions. This paper aims to illustrate how geometry-based graphical methods (GGM) can provide effective support in the conceptual design stage. The paper introduces a novel digital framework for designing and analysing shading devices that leverages geometrical models and graphical methods. The digital implementation of GGM allows extending their applicability to three-dimensional and non-planar geometries. A comprehensive review of existing methods and tools for the design of shading devices lays the ground for the proposed digital framework, which is then demonstrated through two case studies. The results show that the diagrammatic nature of GGM facilitates a better and more direct understanding of the relationship between form and performance.

Purpose: Thyroid nodules classified as TIR3B according to SIAPEC 2014 are considered a clinical challenge due to the risk to be malignant. This retrospective study aimed to compare the performances of total thyroidectomy (TT) and hemithyroidectomy (HT) in the surgical management of a consecutive cohort of patients affected by TIR3B thyroid nodule in terms of side effects and the rate of malignancy detected. Methods: From 2011 to 2019, 136 (111 women, 25 men; average age of 53.5 years) patients having a thyroid nodule with a cytological diagnosis of TIR3B who underwent TT or HT were retrospectively included. Results: Out of 136 patients, 106 (78%) received TT, while the remaining 30 (22%) HT. The final diagnosis was malignant in 65 patients (48%), with follicular variant of papillary carcinoma as the most frequent. The diagnosis of malignancy was significantly more common in the TT group with 56 patients (53%) compared to the HT group with 9 cases (30%) (p= 0.001). Patients who underwent TT were significantly older, had larger nodules and the time between diagnosis and surgery was significantly longer compared to HT (p= 0.001; p0.003; p= 0.002). No main post-surgical complications were registered, except for one case of transient hypocalcemia in a patient who underwent TT. Conclusions: Our data showed a malignancy rate of TIR3B lesions higher than expected (48%). Both TT and HT seem to be effective approaches for the treatment of TIR3B nodules with a very low rate of post-surgical comorbidities. In the choice of surgical approach, it is crucial to consider the presence of risk factors (clinical and ultrasound characteristics), nodule size, patients’ opinion, and surgeon’s skills and experience.

Purpose: In the last years, the role of PET imaging in the assessment of cerebral amyloid angiopathy (CAA) is emerging. In this setting, some tracers have proven their utility for the evaluation of the disease (mainly 11C-Pittsburgh compound B [11C-PIB]), however, the value of other radiotracers has to be clarified. The aim of this systematic review is, therefore, to assess the role of PET imaging in the evaluation of CAA. Methods: A wide literature search of the PubMed/MEDLINE, Scopus, Embase, Web of Science and Cochrane library databases was made to find relevant published articles about the diagnostic performance of PET imaging for the evaluation of CAA. Quality assessment including the risk of bias and applicability concerns was carried out using QUADAS-2 evaluation. Results: The comprehensive computer literature search revealed 651 articles. On reviewing the titles and abstracts, 622 articles were excluded because the reported data were not within the field of interest. Twenty-nine studies were included in the review. In general, PET imaging with amyloid tracers revealed its value for the assessment of CAA, for its differential diagnosis and a correlation with some clinico-pathological features. With less evidence, a role for 18F-fluorodeoxiglucose (18F-FDG) and tau tracers is starting to emerge. Conclusion: PET imaging demonstrated its utility for the assessment of CAA. In particular, amiloid tracers revealed higher retention in CAA patients, correlation with cerebral bleed, the ability to differentiate between CAA and other related conditions (such as Alzheimer's disease) and a correlation with some cerebrospinal fluid biomarkers.

Background: We aimed to test whether the prognostic value of 18 F‐Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) in metastatic castration-resistant prostate cancer (mCRPC) extends to the estimation of systemic treatment response duration. Methods: mCRPC patients submitted to FDG-PET/CT in four Italian centers from 2005 to 2020 were retrospectively enrolled. Clinical and biochemical data at the time of imaging were collected, and SUV max of the hottest lesion, total metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated. The correlation between PET- and biochemical-derived parameters with Overall Survival (OS) was analysed. The prediction of treatment response duration was assessed in the subgroup submitted to FDG-PET/CT in the six months preceding Chemotherapy (namely Docetaxel or Cabazitaxel, 24 patients) or Androgen-Receptor Targeted Agents (ARTA, namely Abiraterone or Enzalutamide, 20 patients) administration. Results: We enrolled 114 mCRPC patients followed-up for a median interval lasting 15 months. While at univariate analysis, prostate-specific antigen (PSA), Alkaline Phosphatase (ALP), MTV, and TLG were associated with OS, at the multivariate Cox regression analysis, the sole MTV could independently predict OS (p< 0.0001). In the subgroup submitted to FDG-PET/CT before the systemic treatment initiation, PSA and TLG could also predict treatment response duration independently (p< 0.05). Of note, while PSA could not indicate the best treatment choice, lower TLG was associated with higher success rates for ARTA but had no impact on chemotherapy efficacy. Conclusions: FDG-PET/CT’s prognostic value extends to predicting treatment response duration in mCRPC, thus potentially guiding the systemic treatment selection.

The fungus Aspergillus flavuscan produce high, unsafe levels of aflatoxin in maize (Zea maysL.) and other high‐oil seed crops under environmental conditions favoring fungal growth and sporulation. At high levels, aflatoxin can kill, and chronic exposure to lower levels causes liver cancer, stunted growth during childhood, and depressed immune systems in humans and animals. Aspergillus ear rot (AER) is especially problematic in tropical environments, but most gene identification studies have been done in temperate or subtropical maize. Thus, the objectives of this research include identifying and mapping chromosomal regions and genes associated with AER resistance in tropical maize inbred lines via genome‐wide association study (GWAS) and tying these genes to metabolic pathways and potential resistance mechanisms. A panel of 320 tropical field corn and popcorn inbred lines was analyzed with phenotypic data for AER collected in two environments after harvest, and a set of 291,633 high‐quality polymorphic single‐nucleotide polymorphisms (SNPs) generated via genotyping by sequencing. Seven SNPs significantly associated with AER were identified. Pathway analysis identified 56 associated pathways, yielding possible resistance mechanisms related to flavonoid and phytoalexin plant compounds, plant signaling via hormones, starch biosynthesis, and general plant growth and metabolism. Many of the same genes were identified by both analyses, but GWAS and pathway analysis jointly identified more candidate genes than either alone. Genome‐wide association study (GWAS) in a tropical maize panel found single‐nucleotide polymorphisms associated with Aspergillus ear rot (AER) resistance.A metabolic pathway analysis of the GWAS results found pathways associated with AER.Important pathways included hormone mediated signaling, flavonoid, and phytoalexin biosynthesis.

Background: Physiological focal radiopharmaceutical uptake in the head and uncinate process of the pancreas may be seen on somatostatin receptor-based PET/CT and might lead to false-positive results for neuroendocrine tumours (NETs). We aimed to perform a systematic review and a meta-analysis about the prevalence of this finding. Methods: We performed a comprehensive computer literature search across several databases until July 2020. Pooled prevalence of physiological focal uptake on somatostatin receptor-based PET/CT in the pancreas was calculated on a per-examination-based analysis and 95% confidence interval values (95% CI) were reported. Results: Six studies (684 patients and 829 PET/CT scans) were included. The pooled prevalence of physiological uptake in the head and uncinate process of the pancreas on somatostatin receptor-based PET/CT imaging was 34% (95% CI 19.5–48.7%) with average SUVmax values ranging from 5 to 12.6. Heterogeneity was seen across the selected studies. Conclusions: High radiopharmaceutical uptake in the head and uncinate process of the pancreas is frequent at somatostatin receptor-based PET/CT and it should be recognized by nuclear medicine physicians to prevent unnecessary additional investigations. In addition, next generation PET/CT tomographs might increase the prevalence of this finding.

El objetivo de este estudio fue investigar la precisión diagnóstica de la PET/TC con 18F-FDG en la estadificación del cáncer de laringe, comparar estos resultados con las técnicas de imagen convencional (CI) y evaluar los parámetros metabólicos para predecir la supervivencia.

This study focuses on the inkjet printing of aluminum-doped zinc oxide (AZO) spherical and platelet nanoparticle-based nanoflakes with typical sizes ranging from 700 to 800 nm. The AZO nanoparticles were synthesized by aqueous precipitation. The preparation of the solvent-based inks was performed with the control of the viscosity, ink stability, and nanoparticle dispersion. The results showed that the viscosity for nanoparticle dispersions slightly changes (from 6.9 to 8.7 cPs) when the nanoparticles mass concentration increases from 1.8 to 10%. In order to achieve thin films of AZO nanoparticles, we optimized the printing process by real-time monitoring of drop velocity with a stroboscopic camera. This technology involves direct patterning of a functional material by tiny MEMS-jets on a flexible and rigid substrate at specific locations. The lowest concentration of AZO nanoparticles corresponding to 1.8% enables printing several times during the nanoparticle dispersions and the clogging of printhead nozzles is less pronounced. In our conditions, the optimum voltage value is 25 V to achieve a drop velocity from 7 to 9 m/s. In the case of nanospheres with 10% of AZO nanoparticles, for a large dropspace (90 μm), the individual printed droplets appear as a sequence of linear dots. When the drop spacing decreases to 75 μm, isolated drops start to overlap and merge. Further decrease in the drop spacing eliminates scalloping and leads finally to a regular and continuous layer at 55 μm.

Balint syndrome is a rare neurological disorder characterized by simultanagnosia, optic ataxia, and ocular apraxia, and its etiology can be very heterogeneous. Diagnosis is based on neuropsychological evaluation, but brain radiological and nuclear medicine imaging also plays an important role. Because few case reports have been published in literature, in this work, we present 2 patients affected by Balint syndrome in which 18F-FDG PET/CT helped in the diagnosis and follow-up.

A 79-year-old man with a history of prostate adenocarcinoma treated with prostatectomy underwent 18F-FCH PET/CT for restaging purpose, which was negative for relapse but showed the presence of choline-positive lymph nodes in the left axilla. The patient underwent a COVID-19 vaccination in the left arm 6 days prior. Thus, PET/CT findings were considered as inflammatory lymph nodes. With the current drive of global COVID-19 immunization, this case underlines the importance of knowing vaccination history to interpret correctly the findings and to avoid false-positive reports.

Aim: The diagnosis, severity and extent of a sterile inflammation or a septic infection could be challenging since there is not one single test able to achieve an accurate diagnosis. The clinical use of 18F-fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) imaging in the assessment of inflammation and infection is increasing worldwide. The purpose of this paper is to achieve an Italian consensus document on [18F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases, such as osteomyelitis (OM), prosthetic joint infections (PJI), infective endocarditis (IE), prosthetic valve endocarditis (PVE), cardiac implantable electronic device infections (CIEDI), systemic and cardiac sarcoidosis (SS/CS), diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), fever and inflammation of unknown origin (FUO/IUO), pediatric infections (PI), inflammatory bowel diseases (IBD), spine infections (SI), vascular graft infections (VGI), large vessel vasculitis (LVV), retroperitoneal fibrosis (RF) and COVID-19 infections. Methods: In September 2020, the inflammatory and infectious diseases focus group (IIFG) of the Italian Association of Nuclear Medicine (AIMN) proposed to realize a procedural paper about the clinical applications of [18F]FDG PET/CT or PET/MRI in inflammatory and infectious diseases. The project was carried out thanks to the collaboration of 13 Italian nuclear medicine centers, with a consolidate experience in this field. With the endorsement of AIMN, IIFG contacted each center, and the pediatric diseases focus group (PDFC). IIFG provided for each team involved, a draft with essential information regarding the execution of [18F]FDG PET/CT or PET/MRI scan (i.e., indications, patient preparation, standard or specific acquisition modalities, interpretation criteria, reporting methods, pitfalls and artifacts), by limiting the literature research to the last 20 years. Moreover, some clinical cases were required from each center, to underline the teaching points. Time for the collection of each report was from October to December 2020. Results: Overall, we summarized 291 scientific papers and guidelines published between 1998 and 2021. Papers were divided in several sub-topics and summarized in the following paragraphs: clinical indications, image interpretation criteria, future perspectivess and new trends (for each single disease), while patient preparation, image acquisition, possible pitfalls and reporting modalities were described afterwards. Moreover, a specific section was dedicated to pediatric and PET/MRI indications. A collection of images was described for each indication. Conclusions: Currently, [18F]FDG PET/CT in oncology is globally accepted and standardized in main diagnostic algorithms for neoplasms. In recent years, the ever-closer collaboration among different European associations has tried to overcome the absence of a standardization also in the field of inflammation and infections. The collaboration of several nuclear medicine centers with a long experience in this field, as well as among different AIMN focus groups represents a further attempt in this direction. We hope that this document will be the basis for a “common nuclear physicians’ language” throughout all the country.

Purpose: The aim of this study was to assess the potential role of thyroglobulin (Tg) kinetics in predicting 2-[18F]-FDG-PET/CT results and overall survival (OS) in patients affected by differentiated thyroid carcinoma (DTC) and suspected recurrence. Methods: On hundred and thirty-nine patients were retrospectively included. All patients underwent 2-[18F]-FDG-PET/CT due to detectable Tg levels and negative [131I] whole-body scan. The last two consecutive serum Tg measurements before PET/CT were used for Tg-doubling time (TgDT) and Tg-velocity (Tg-vel) calculation. Receiver operating characteristic (ROC) curves were used to determine the optimal cutoff points for Tg, TgDT and Tg-vel for predicting PET/CT results. Results: One hundred and fifteen (83%) patients had positive PET/CT for DTC recurrence, while the remaining 24 (17%) negative. Stimulated Tg before PET and Tg-vel were significantly higher in patients with a positive PET/CT scan than negative scan (average Tg 190 vs 14 ng/mL, p= 0.006; average Tg-vel 4.2 vs 1.7 ng/mL/y, p< 0.001). Instead, TgDT was significantly shorter in positive scan (average TgDT 1.4 vs 4.4 years, p< 0.001). ROC curve analysis revealed the best Tg, TgDT and Tg-vel cutoff of 18 ng/mL,1.36 years and 1.95 ng/mL/y. In patients with Tg<18 ng/mL, the PET/CT detection rate was significantly lower in patients with low Tg-vel (p= 0.018) and with long TgDT (p= 0.001). ATA class risk, PET/CT results and Tg before PET were confirmed to be independent prognostic variables for OS. Conclusions: Tg kinetics may help to predict 2-[18F]-FDG-PET/CT results in DTC patients with negative [131I]WBS and detectable Tg, especially in case of low-moderate Tg.

The fate of hematopoietic stem and progenitor cells (HSPC) is tightly regulated by their bone marrow (BM) microenvironment (ME). BM transplantation (BMT) frequently requires irradiation preconditioning to ablate endogenous hematopoietic cells. Whether the stromal ME is damaged and how it recovers after irradiation is unknown. We report that BM mesenchymal stromal cells (MSC) undergo massive damage to their mitochondrial function after irradiation. Donor healthy HSPC transfer functional mitochondria to the stromal ME, thus improving mitochondria activity in recipient MSC. Mitochondrial transfer to MSC is cell-contact dependent and mediated by HSPC connexin-43 (Cx43). Hematopoietic Cx43-deficient chimeric mice show reduced mitochondria transfer, which was rescued upon re-expression of Cx43 in HSPC or culture with isolated mitochondria from Cx43 deficient HSPCs. Increased intracellular adenosine triphosphate levels activate the purinergic receptor P2RX7 and lead to reduced activity of adenosine 5′-monophosphate–activated protein kinase (AMPK) in HSPC, dramatically increasing mitochondria transfer to BM MSC. Host stromal ME recovery and donor HSPC engraftment were augmented after mitochondria transfer. Deficiency of Cx43 delayed mesenchymal and osteogenic regeneration while in vivo AMPK inhibition increased stromal recovery. As a consequence, the hematopoietic compartment reconstitution was improved because of the recovery of the supportive stromal ME. Our findings demonstrate that healthy donor HSPC not only reconstitute the hematopoietic system after transplantation, but also support and induce the metabolic recovery of their irradiated, damaged ME via mitochondria transfer. Understanding the mechanisms regulating stromal recovery after myeloablative stress are of high clinical interest to optimize BMT procedures and underscore the importance of accessory, non-HSC to accelerate hematopoietic engraftment.

The fate of hematopoietic stem and progenitor cells (HSPC) is tightly regulated by their bone marrow (BM) microenvironment (ME). BM transplantation (BMT) frequently requires irradiation preconditioning to ablate endogenous hematopoietic cells. Whether the stromal ME is damaged and how it recovers after irradiation is unknown. We report that BM mesenchymal stromal cells (MSC) undergo massive damage to their mitochondrial function after irradiation. Donor healthy HSPC transfer functional mitochondria to the stromal ME, thus improving mitochondria activity in recipient MSC. Mitochondrial transfer to MSC is cell-contact dependent and mediated by HSPC connexin-43 (Cx43). Hematopoietic Cx43-deficient chimeric mice show reduced mitochondria transfer, which was rescued upon re-expression of Cx43 in HSPC or culture with isolated mitochondria from Cx43 deficient HSPCs. Increased intracellular adenosine triphosphate levels activate the purinergic receptor P2RX7 and lead to reduced activity of adenosine 5′-monophosphate–activated protein kinase (AMPK) in HSPC, dramatically increasing mitochondria transfer to BM MSC. Host stromal ME recovery and donor HSPC engraftment were augmented after mitochondria transfer. Deficiency of Cx43 delayed mesenchymal and osteogenic regeneration while in vivo AMPK inhibition increased stromal recovery. As a consequence, the hematopoietic compartment reconstitution was improved because of the recovery of the supportive stromal ME. Our findings demonstrate that healthy donor HSPC not only reconstitute the hematopoietic system after transplantation, but also support and induce the metabolic recovery of their irradiated, damaged ME via mitochondria transfer. Understanding the mechanisms regulating stromal recovery after myeloablative stress are of high clinical interest to optimize BMT procedures and underscore the importance of accessory, non-HSC to accelerate hematopoietic engraftment.

Fusarium ear rot (FER), caused by Fusarium verticillioides(Sacc.) Nirenberg, is one of the major ear diseases that affect both yield and grain quality in maize (Zea maysL.), especially in tropical environments. Fusariumgenetic resistance is a complex trait, controlled by several small‐effect genes and strongly influenced by the environment. We applied a comprehensive genome‐wide association study and genomic prediction for ear rot and starburst symptoms, using 291,633 high‐quality single nucleotide polymorphism (SNPs) markers in 320 tropical maize inbred lines, in two distinct locations in Brazil's southern region. Three SNPs were significantly associated with starburst symptoms, each associated with 6–8% of the phenotypic variance, and with gene models that have expression levels in ears, pericarp, and kernels, corresponding to disease infection period and suggesting some role in FER resistance. No significant SNP was associated with FER, which is an indication that the genetic architecture for this trait is highly polygenic, with potentially many variants having small effects that are not detectable in the association mapping analysis. We observed genomic prediction accuracies ranging from 0.34 to 0.4 for FER and starburst, respectively. Further research is required to validate these significant SNPs and their relationship to genes affecting FER resistance, and also to improve genomic prediction accuracies across different genetic backgrounds.

Cushing's disease is a rare endocrine disorder characterised by cortisol overproduction with severe complications. Therapies for cortisol reduction are often necessary. Here we report the outcomes from the pivotal phase III study of osilodrostat (a potent oral inhibitor of cytochrome P450 11B1, mitochondrial [11β-hydroxylase]; Novartis Pharma AG, Basel, Switzerland) in patients with Cushing's disease.

Supplemental Digital Content is available in the text.

El comportamiento metabólico del plasmocitoma en la PET/TC con 18F-FDG no está claro.

Purpose: The aim of our study was to compare the efficacy of thyroid remnant ablation using low (1.1 GBq) and intermediate-high radioiodine (RAI) activity (1.85–3.7 GBq) in low-risk differentiated thyroid carcinoma (DTC) and to evaluate the staging role of the whole body scan (WBS) in detection extrathyroidal disease. Materials and methods: We retrospectively included 277 patients who underwent total thyroidectomy and RAI for low-risk DTC and divided them in two groups according to RAI activity at ablation: group 1 (n= 174) treated with low activity (1.1 GBq), and group 2 (n= 103) with intermediate-high activity (1.85–3.7 GBq). To evaluate the successful ablation rate, the WBS 1 year after RAI was visually interpreted using a three-point scale: score 0 in case of absence of visible RAI uptake in thyroid bed; score 1 in presence of faint uptake in the thyroid bed; and score 2 in case of significant RAI uptake in thyroid bed. Results: The success ablation rate was significantly higher in group 2 than group 1 (p< 0.001) with the presence of a positive WBS (score 1–2) in 65% low-activity group and 33% in intermediate-high group. Considering response to therapy categories, excellent response rate was significantly higher in group 2 (p= 0.020), while indeterminate response was higher in group 1 (pvalue = 0.005). Post RAI imaging revealed extrathyroidal uptake in 27 cases: 17 laterocervical nodal and 10 distant metastases. In both groups similar detection rate of nodal and distant metastases were recognized without any statistical difference. Conclusions: The ablation rate with intermediate-high RAI activity (1.85–3.7 GBq) was better than with a low activity (1.1 GBq). First WBS may help to recognize nodal and distant metastases in about 10% of cases changing clinical stage and subsequent management.

Ewing sarcoma (ES) is one of the most common pediatric solid tumors with aggressive behavior and unfavorable survival. In this study, we evaluated the diagnostic accuracy of baseline and restaging fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) scans and their possible prognostic role in pediatric ES. We evaluated 17 patients who underwent a total of 27 18F-FDG-PET/CT scans (10 for staging and 17 for restaging). The PET images were analyzed visually and semiquantitatively by measuring SUVmean, SUVmax, SUVlbm, SUVbsa, MTV, and TLG. Moreover, PET/CT results were compared with other conventional imaging (CI) results. Among 10 baseline PET/CT scan results, 9 were positive and 1 not valuable by interference; baseline PET/CT and CI were concordant in 7 cases and discordant in 2, with pulmonary micrometastases not detected by PET/CT. Among 17 restaging PET/CT scan results, 9 were positive and 8 negative; CI and restaging PET/CT were concordant in 9 cases and discordant in 8. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of restaging 18F-FDG-PET/CT were 73%, 83%, 89%, 62.5%, and 76%, respectively. After a median follow-up of 20 months, relapse/progression occurred in 8 patients and death in 5. A positive 18F-FDG-PET/CT at restaging was significantly associated with shorter overall survival compared with unremarkable PET/CT at the same timepoint, but not with progression-free survival. Instead, metabolic PET/CT features were not correlated with outcome. 18F-FDG-PET/CT showed a good diagnostic performance in pediatric ES; except for pulmonary micrometastases, PET/CT was better than CI at restaging. Only restaging PET/CT result was significantly correlated with overall survival.