Long-term trends in total administered radiation dose from brain [18F]FDG-PET in children with drug-resistant epilepsy.

PURPOSE: To assess the trends in administered 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) doses, computed tomography (CT) radiation doses, and image quality over the last 15 years in children with drug-resistant epilepsy (DRE) undergoing hybrid positron emission tomography (PET) brain scans. METHODS: We retrospectively analyzed data from children with DRE who had [18F]FDG-PET/CT or magnetic resonance scans for presurgical evaluation between 2005 and 2021. We evaluated changes in injected [18F]FDG doses, administered activity per body weight, CT dose index volume (CTDIvol), and dose length product (DLP). PET image quality was assessed visually by four trained raters. Conversely, CT image quality was measured using region-of-interest analysis, normalized by signal-to-noise (SNR) and contrast-to-noise ratio (CNR). RESULTS: We included 55 children (30 male, mean age: 9 ± 6 years) who underwent 61 [18F]FDG-PET scans (71% as PET/CT). Annually, the injected [18F]FDG dose decreased by ~ 1% (95% CI: 0.92%-0.98%, p < 0.001), with no significant changes in administered activity per body weight (p = 0.51). CTDIvol and DLP decreased annually by 16% (95% CI: 9%-23%) and 15% (95% CI: 8%-21%, both p < 0.001), respectively. PET image quality improved by 9% year-over-year (95% CI: 6%-13%, p < 0.001), while CT-associated SNR and CNR decreased annually by 7% (95% CI: 3%-11%, p = 0.001) and 6% (95% CI: 2%-10%, p = 0.008), respectively. CONCLUSION: Our findings indicate stability in [18F]FDG administered activity per body weight alongside improvements in PET image quality. Conversely, CT-associated radiation doses reduced. These results reaffirm [18F]FDG-PET as an increasingly safer and higher-resolution auxiliary imaging modality for children with DRE. These improvements, driven by technological advancements, may enhance the diagnostic precision and patient outcomes in pediatric epilepsy surgery.

Diagnostic Performance and Interobserver Agreement of Diuretic 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Diagnosis of Upper Urinary Tract Cancer.

BACKGROUND: Previous reports attempted to evaluate bladder cancer using 18 F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) by washing out the excreted FDG with a diuretic. The purpose of this study was to evaluate the value of diuretic FDG PET/plain CT (drtPET/CT) and diuretic FDG PET/contrast-enhanced CT (drtPET/ceCT) in the assessment of upper urinary tract cancers. MATERIALS AND METHODS: A total of 66 patients underwent drtPET/CT for suspected upper urinary tract cancer (UUTC). The study targeted 29 patients who were strongly suspected of having UUTC and underwent magnetic resonance imaging (MRI) of the upper urinary tract. A total of 29 (24 male, five female) patients, with a mean ± SD age of 73 ± 3 (range, 43-84) years, had a suspected neoplasm in the upper urinary tract. They underwent FDG PET/plain and contrast-enhanced CT before and after a diuretic and MRI including diffusion-weighted imaging (DWI). A urologist and a physician board-certified in nuclear medicine and radiology independently interpreted the standard PET/CT (stdPET/CT), drtPET/CT, drtPET/ceCT, ceCT, and MRI with DWI images. Interobserver agreement and the diagnostic performance of each modality were evaluated. RESULTS: The kappa values of stdPET/CT, drtPET/CT, drtPET/ceCT, ceCT, and MRI were 0.381, 0.567, 0.7031, 0.448, and 0.185, respectively, with drtPET/ceCT showing the highest kappa value and the only one with good interobserver agreement (>60%). The area under the curve of drtPET/ceCT was 0.92, which was significantly higher than those of stdPET/CT (P=0.027) and MRI (P=0.047). CONCLUSIONS: In the present study, drtPET/ceCT had the best diagnostic performance and the highest interobserver agreement for detecting upper urinary tract urothelial cancers.

Arterial inflammation on [18F]FDG PET/CT in melanoma patients treated with and without immune checkpoint inhibitors: CHECK-FLAME I.

BACKGROUND AND AIMS: Immune checkpoint inhibitors (ICIs) revolutionized cancer treatment. However, ICIs may increase the immune response to non-tumor cells, possibly resulting in increased arterial inflammation, raising the risk of atherosclerotic events. Nevertheless, malignancies may induce a pro-inflammatory state and the association between ICIs and arterial inflammation remains to be clarified. This study aims to assess differences in increase in arterial inflammation between patients with advanced melanoma treated with ICIs compared to a control group without ICIs. METHODS: Patients with advanced melanoma who underwent [18F]FDG PET/CT scans at baseline, 6 months (T1) and 18 months (T2) were included in this retrospective observational study. Arterial inflammation was evaluated in eight segments by calculating the target-to-background ratio (TBR). The primary study outcome was the difference in increase in mean TBRmax between patients treated with and without ICIs. RESULTS: We included 132 patients of whom 72.7 % were treated with ICIs. After exclusion for the use of anti-inflammatory medication, patients treated with ICIs showed a significant increase in mean TBRmax between baseline and T1 from 1.29 ± 0.12 to 1.33 ± 0.13 (p = 0.017), while in the control group, no change in mean TBRmax (1.30 ± 0.12 to 1.28 ± 0.10, p = 0.22) was observed (p = 0.027). During longer follow-up, mean TBRmax remained stable in both groups. Arterial inflammation increased significantly after ICI therapy in patients without active inflammation (p < 0.001) and in patients without calcifications (p = 0.013). CONCLUSIONS: A significant increase in arterial inflammation as measured on [18F]FDG PET/CT was observed in patients with advanced melanoma treated with ICIs only in the first six months after initiation of therapy, whereas no changes were observed in the control group. Moreover, arterial inflammation was mainly increased in patients without pre-existing inflammatory activity and with non-calcified lesions.

What do we know About the Usefulness of 18F-FDG PET-CT for the Management of Invasive Fungal Infection? An International Survey.

BACKGROUND: Recent data support 18F-FDG PET-CT for the management of infections in immunocompromised patients, including invasive fungal infection (IFI). However, its role is not well established in clinical practice. We performed an international survey to evaluate the knowledge of physicians about the usefulness of 18F-FDG PET-CT in IFI, in order to define areas of uncertainty. METHODS: An online survey was distributed to infectious diseases working groups in December 2023-January 2024. It included questions regarding access to 18F-FDG PET-CT, knowledge on its usefulness for IFI and experience of the respondents. A descriptive analysis was performed. RESULTS: 180 respondents answered; 60.5% were Infectious Diseases specialists mainly from Spain (52.8%) and Italy (23.3%). 84.4% had access to 18F-FDG PET-CT at their own center. 85.6% considered that 18F-FDG PET-CT could be better than conventional tests for IFI. In the context of IFI risk, 81.1% would consider performing 18F-FDG PET-CT to study fever without a source and around 50% to evaluate silent lesions and 50% to assess response, including distinguishing residual from active lesions. Based on the results of the follow-up 18F-FDG PET-CT, 56.7% would adjust antifungal therapy duration. 60% would consider a change in the diagnostic or therapeutic strategy in case of increased uptake or new lesions. Uncovering occult lesions (52%) and diagnosing/excluding endocarditis (52.7%) were the situations in which 18F-FDG PET-CT was considered to have the most added value. There was a great variability in responses about timing, duration of uptake, the threshold for discontinuing treatment or the influence of immune status. CONCLUSION: Although the majority considered that 18F-FDG PET-CT may be useful for IFI, many areas of uncertainty remain. There is a need for protocolized research to improve IFI management.

Evaluation of 68Ga-FAPI PET/CT and 18F-FDG PET/CT for the diagnosis of recurrent colorectal cancers.

Objective: The present study aimed to compare the diagnostic value of gallium-68-labeled fibroblast activation protein inhibitor positron emission tomography/computed tomography (68Ga-FAPI PET/CT) and fluorine-18-labeled fluorodeoxyglucose PET/CT (18F-FDG PET/CT) for detecting recurrent colorectal cancers (CRCs). Materials and Methods: Fifty-six patients (age: 18-80 years, 31 men and 25 women) with suspected recurrent CRC were enrolled and underwent 18F-FDG PET/CT and 68Ga-FAPI PET/CT sequentially within 1 week. The maximum standard uptake value (SUVmax), tumor-to-background ratio (TBR), and diagnostic accuracy were estimated and compared between the two modalities by using Student's t-test. The Wilcoxon signed-rank test was used to compare peritoneal carcinoma index (PCI) scores between the two imaging modalities. Results: 68Ga-FAPI PET/CT showed higher sensitivity for detecting recurrence (93 % vs. 79 %); lymph node metastasis (89 % vs. 78 %), particularly peritoneal lymph node metastasis (92 % vs. 63 %); and metastatic implantation on the intestinal wall (100 % vs. 25 %) compared to 18F-FDG PET/CT. However, 68Ga-FAPI PET/CT showed lower sensitivity for detecting bone metastasis (67 % vs. 100 %). The mean SUVmax values of peritoneal metastases and metastatic implantation on the intestinal wall were 4.28 ± 2.70 and 7.58 ± 1.66 for 18F-FDG PET/CT and 5.66 ± 1.97 and 6.70 ± 0.25 for 68Ga-FAPI PET/CT, respectively. Furthermore, 68Ga-FAPI PET/CT showed significantly higher TBR for peritoneal metastatic lesions (4.22 ± 1.47 vs. 1.41 ± 0.89, p < 0.0001) and metastatic implantation on the intestinal wall (5.63 ± 1.24 vs. 2.20 ± 0.5, p = 0.02) compared to 18F-FDG PET/CT. For the same patient, 68Ga-FAPI PET/CT yielded a more accurate PCI score and a greater area under the curve value for the receiver operating characteristic curve (p < 0.01) than 18F-FDG PET/CT. Conclusion: 68Ga-FAPI PET/CT was superior to 18F-FDG PET/CT for detecting recurrence and peritoneal metastases. Hence, we propose the combination of these two modalities for better clinical diagnosis and management of patients with CRC.

Deep learning-based image analysis predicts PD-L1 status from 18F-FDG PET/CT images in non-small-cell lung cancer.

Background: There is still a lack of clinically validated biomarkers to screen lung cancer patients suitable for programmed dead cell-1 (PD-1)/programmed dead cell receptor-1 (PD-L1) immunotherapy. Detection of PD-L1 expression is invasively operated, and some PD-L1-negative patients can also benefit from immunotherapy; thus, the joint modeling of both deep learning images and clinical features was used to improve the prediction performance of PD-L1 expression in non-small cell lung cancer (NSCLC). Methods: Retrospective collection of 101 patients diagnosed with pathology in our hospital who underwent 18F FDG PET/CT scans, with lung cancer tissue Tumor Propulsion Score (TPS) ≥1% as a positive expression. Lesions were extracted after preprocessing PET/CT images, and using deep learning 3D DenseNet121 to learn lesions in PET, CT, and PET/CT images, 1,024 fully connected features were extracted; clinical features (age, gender, smoking/no smoking history, lesion diameter, lesion volume, maximum standard uptake value of lesions [SUVmax], mean standard uptake value of lesions [SUVmean], total lesion glycolysis [TLG]) were combined for joint modeling based on the structured data Category Embedding Model. Results: Area under a receiver operating characteristic (ROC) curve (AUC) and accuracy of predicting PD-L1 positive for PET, CT, and PET/CT test groups were 0.814 ± 0.0152, 0.7212 ± 0.0861, and 0.90 ± 0.0605, 0.806 ± 0.023, 0.70 ± 0.074, and 0.950 ± 0.0250, respectively. After joint clinical feature modeling, the AUC and accuracy of predicting PD-L1 positive for PET/CT were 0.96 ± 0.00905 and 0.950 ± 0.0250, respectively. Conclusion: This study combines the features of 18F-FDG PET/CT images with clinical features using deep learning to predict the expression of PD-L1 in NSCLC, suggesting that 18F-FDG PET/CT images can be conducted as biomarkers for PD-L1 expression.

Impact of [18F] FDG PET/CT on outcomes in patients with Staphylococcus aureus bacteremia: A retrospective single-center experience.

OBJECTIVE: Staphylococcus aureus bacteremia (SAB) is a leading cause of community and hospital-acquired bacteremia with significant morbidity and mortality. Effective management depends on accurate diagnosis, source control and assessment of metastatic infections. [18F] FDG PET/CT has been shown to reduce mortality in high-risk SAB patients. This study aims to evaluate the impact of [18F] FDG PET/CT on outcomes in patients with SAB. METHODS: Single-center, retrospective, real-life setting study including all consecutive SAB cases from 2017 to 2019. Medical records were analyzed to collect information. RESULTS: Out of the 315 included patients, 132 underwent [18F] FDG PET/CT. In those patients, a clear focus of infection was more frequently identified, leading to better adapted treatments and extended hospital stays. Overall mortality rates at 30 days, 90 days and one year were 25.1 %, 36.8 % and 44.8 % respectively. Mortality was significantly lower in the [18F] FDG PET/CT group (p < 0.0001) and persisted (p < 0.05) after adjusting for imbalances between groups regarding oncologic patients and deaths within 7 days. The difference in mortality remained significant irrespective of prolonged bacteremia but was not significant with regard to hospital-acquired SAB. Supplementary analysis using the Cox proportional hazards model confirmed that [18F] FDG PET/CT was significantly associated with reduced mortality (p < 0.05). CONCLUSION: In this real-life cohort, patients with SAB having undergone [18F] FDG PET/CT experienced lower mortality rates, highlighting the additional value of [18F] FDG PET/CT in SAB management. Further research is needed to identify the subpopulations that would benefit most from the integration of [18F] FDG PET/CT in their work-up.

IMPeTUs parameters correlate with clinical features in newly diagnosed multiple myeloma.

Objectives: To investigate the correlations between IMPeTUs-based 18 F-FDG PET/CT parameters and clinical features in patients with newly diagnosed multiple myeloma (MM). Materials and methods: PET/CT were analysed according to the IMPeTUs criteria. We correlated these PET/CT parameters with known clinically relevant features, bone marrow plasma cell (BMPC) infiltration rate and the presence of cytogenetic abnormalities. Results: A total of 149 patients (86 males, 63 females; mean age, 59.9 ± 9.7 years) were included. Bone marrow metabolic state correlated with the most clinical features including hemoglobin (rho=-0.23, p=0.004), FLC ratio (rho=0.24, p=0.005), ß2 M (rho=0.28, p=0.001), CRP (rho=0.25, p=0.003), serum calcium (rho=0.22, p=0.02), serum creatinine (rho=0.24, p=0.004) and BMPC (rho=0.21, p=0.003). Besides, the level of hemoglobin was significant lower (0.043), and the levels of FLC ratio (0.037), ß2 M (p=0.024), CRP (p=0.05), and BMPC (p=0.043) were significant higher in patients having hypermetabolism in limbs and ribs. Hottest bone lesion Deauville criteria had a moderate correlation with CRP (rho=0.27, p=0.001) and serum calcium (rho=0.25, p=0.01). Conclusion: Several IMPeTUs-based PET/CT parameters showed significant correlations with clinical features reflecting disease burden and biology, suggesting that these new criteria can be used in the risk stratification in MM patients.

Evaluation of prognostic risk factors of triple-negative breast cancer with 18F-FDG PET/CT parameters, clinical pathological features and biochemical indicators.

Introduction: Breast cancer is a heterogeneous disease comprising various molecular subtypes, including Luminal A, Luminal B, human epidermal growth factor receptor-2 (HER2) positive, and triple negative types, each with distinct biological characteristics and behaviors. Triple negative breast cancer (TNBC) remains a particularly challenging subtype worldwide. Our study aims to evaluate whether Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) parameters, clinical pathological features, and biochemical indicators serve as prognostic risk factors for TNBC. Additionally, we explore correlations between biochemical indicators and 18F-FDG PET/CT parameters. Methods: We conducted a retrospective analysis of 95 TNBC patients who underwent preoperative 18F-FDG PET/CT examinations at Tianjin Medical University Cancer Institute and Hospital from 2013 to 2018. Collected data included 18F-FDG PET/CT parameters, clinical and pathological features, and biochemical indicators. We used Kaplan-Meier survival analysis and multivariate Cox regression analysis to evaluate associations between 18F-FDG PET/CT parameters/biochemical indicators and disease free survival (DFS)/overall survival (OS). The log-rank test determined significant differences in survival curves, and the Spearman correlation coefficient analyzed correlations between quantitative variables. Visualization and analysis were performed using R packages. Results: Among 95 TNBC patients, mean standardized uptake value (SUVmean) was significantly correlated with DFS. Fasting blood glucose (FBG), α- L-fucosylase (AFU) and Creatine kinase (CK) were independent predictors of DFS, while Precursor albumin (PALB) and CK were independent predictors of OS. FBG showed correlations with SUVpeak and SUVmean, and CK was correlated with peak standardized uptake value (SUVpeak). Our results indicated that 18F-FDG PET/CT parameters and biochemical indicators may constitute a new prognostic model for TNBC patients post-surgery. Discussion: We found that SUVmean, FBG, AFU and CK are predictive factors for DFS in TNBC patients post-surgery, while PALB and CK are predictive factors for OS, which prompts us to pay more attention to these indicators in clinical practice. Also 18F-FDG PET/CT parameters and biochemical indicators have potential utility in constituting a new prognostic model for TNBC patients post-surgery.

Applicability and performance of 18F-FDG PET-based modalities for whole-body cancer screening: a systematic review and meta-analysis.

PURPOSE: Screening tests are the cornerstone for early detection and optimal management of cancers. Most of the present cancer-screening tests are intrusive, time-consuming, and specifically target a particular anatomical site or cancer type. Only a few studies have reported the objective measures of 18F-FDG PET-based cancer screening in asymptomatic individuals. This review and meta-analysis is an attempt to assess the applicability and performance of 18F-FDG PET-based modalities for whole-body cancer screening. MATERIALS AND METHODS: The systematic review and meta-analysis were performed following PRISMA guidelines. Literature searches in PubMed, Scopus, and Embase were conducted using relevant MeSH terms and keywords, for articles published in the last 2 decades (2000-2022). Pooled estimates of diagnostic test accuracy-including sensitivity, specificity, positive-likelihood ratio, negative-likelihood ratio, and hierarchical summary ROC (HSROC) curve were generated using bivariate random-effects meta-analysis. RESULTS: Seventeen studies were included in the systematic review and 13 studies were deemed eligible for meta-analysis. The mean estimates of pooled sensitivity, specificity, positive-likelihood ratio, negative-likelihood ratio, and Odds ratio using 18F-FDG PET with a 95% confidence interval were 0.47 (0.25-0.69), 0.97 (0.95-0.98), 18.8 (6.8-51.5), 0.45 (0.27-0.76), 41.0 (7.9-211.8) and for 18F-FDG PET/CT were 0.83 (0.75-0.88), 0.98 (0.97-0.99), 49.7 (29.2-84.5), 0.15 (0.8-0.28), 329.9 (125.0-870.8), respectively. Among screening modalities, 18F-FDG PET/CT had a higher accuracy i.e., the area under the HSROC curve (AUC): 0.91 (0.87-0.95) compared to 18F-FDG PET: 0.72 (0.61-0.82). CONCLUSION: This study demonstrates that currently 18F-FDG PET-based screening has limited applicability for population-based cancer-screening programs. However, it has a promising role as a combined screening strategy for at-risk individuals and allows for comprehensive diagnostic and prognostic evaluation in high-resource settings.

[18F]FDG-PET/CT in adrenal lesions: diagnostic performance in different clinical settings.

PURPOSE: Data regarding [18F]FDG-PET/CT for the characterization of adrenal lesions are limited. Most of the studies proposed the tumor-to-liver maximum standardized uptake values (SUVratio) > 1.5 as the best cut off to predict malignancy. The aim of the study was to calculate the optimum cut off in a heterogeneous population with adrenal lesions and evaluate the diagnostic performance SUVratio >1.5. PATIENTS AND METHODS: Retrospective analysis of adrenal lesions undergoing [18F]FDG-PET/CT (2013-2022) for different reasons (atypical adrenal incidentalomas, extra adrenal tumor staging). The diagnosis of benignity was assessed by: (i) histology; (ii) stability or minimal diameter increase (<20%/<5 mm) on 12-months follow-up for non-operated patients. The optimal SUVratio and performance of SUVratio >1.5 were calculated by ROC curves. RESULTS: Forty-two consecutive lesions (diameter 36.1 ± 20.3 mm, 6 bilateral) underwent [18F]FDG-PET/CT (19F, age 61.2 ± 11.7 years). Twenty-nine lesions were benign, 11 malignant [8 metastases (2 bilateral) and 1 adrenocortical carcinoma (ACC)] and 2 pheochromocytomas. The SUVratio cut-off in our population was 1.55 (Sn 100%, Sp 73.7%, AUC 0.868), with similar values excluding pheochromocytomas and metastases (SUVratio cut-off 1.49, Sn 100%, Sp 96.3%, AUC 0.988). The SUVratio cut-off of 1.5 showed 100% Sn, 87% Sp, 73% PPV, and 100% NPV. CONCLUSION: [18F]FDG-PET/CT could help in decision making process avoiding unnecessary surgery. The SUVratio cut-off of 1.5 has a good performance in a heterogenous population.

18F-FDG PET/CT metrics-based stratification of large B-cell lymphoma receiving CAR-T cell therapy: immunosuppressive tumor microenvironment as a negative prognostic indicator in patients with high tumor burden.

Chimeric antigen receptor T (CAR-T) cell therapy has greatly improved the prognosis of relapsed and refractory patients with large B-cell lymphoma (LBCL). Early identification and intervention of patients who may respond poorly to CAR-T cell therapy will help to improve the efficacy. Ninety patients from a Chinese cohort who received CAR-T cell therapy and underwent 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scans at the screening stage (median time to infusion 53.5 days, range 27-176 days), 1 month and 3 months after CAR-T cell infusion were analyzed, with RNA-sequencing conducted on 47 patients at the screening stage. Patients with maximum diameter of the largest lesion (Dmax) < 6 cm (N = 60) at screening stage showed significantly higher 3-month complete response rate (85.0% vs. 33.3%, P < 0.001), progression-free survival (HR 0.17; 95% CI 0.08-0.35, P < 0.001) and overall survival (HR 0.18; 95% CI 0.08-0.40, P < 0.001) than those with Dmax ≥ 6 cm (N = 30). Besides, at the screening stage, Dmax combined with extranodal involvement was more efficient in distinguishing patient outcomes. The best cut-off values for total metabolic tumor volume (tMTV) and total lesion glycolysis (tTLG) at the screening stage were 50cm3 and 500 g, respectively. A prediction model combining maximum standardized uptake value (SUVmax) at 1 month after CAR-T cell therapy (M1) and tTLG clearance rate was established to predict early progression for partial response/stable disease patients evaluated at M1 after CAR-T cell therapy and validated in Lyon cohort. Relevant association of the distance separating the two farthest lesions, standardized by body surface area to the severity of neurotoxicity (AUC = 0.74; P = 0.034; 95% CI, 0.578-0.899) after CAR-T cell therapy was found in patients received axicabtagene ciloleucel. In patients with Dmax ≥ 6 cm, RNA-sequencing analysis conducted at the screening stage showed enrichment of immunosuppressive-related biological processes, as well as increased M2 macrophages, cancer-associated fibroblasts, myeloid-derived suppressor cells, and intermediate exhausted T cells. Collectively, immunosuppressive tumor microenvironment may serve as a negative prognostic indicator in patients with high tumor burden who respond poorly to CAR-T cell therapy.

Role of quantitative imaging biomarkers in an early FDG-PET/CT for detection of immune-related adverse events in melanoma patients: a prospective study.

BACKGROUND: To evaluate the role of the novel quantitative imaging biomarker (QIB) SUVX% of 18F-FDG uptake extracted from early 18F-FDG-PET/CT scan at 4 weeks for the detection of immune-related adverse events (rAE) in a cohort of patients with metastatic melanoma (mM) patients receiving immune-checkpoint inhibitors (ICI). PATIENTS AND METHODS: In this prospective non-interventional, one-centre clinical study, patients with mM, receiving ICI treatment, were regularly followed by 18F-FDG PET/CT. Patients were scanned at baseline, early point at week four (W4), week sixteen (W16) and week thirty-two (W32) after ICI initiation. A convolutional neural network (CNN) was used to segment three organs: lung, bowel, thyroid. QIB of irAE - SUVX% - was analyzed within the target organs and correlated with the clinical irAE status. Area under the receiver-operating characteristic curve (AUROC) was used to quantify irAE detection performance. RESULTS: A total of 242 18F-FDG PET/CT images of 71 mM patients were prospectively collected and analysed. The early W4 scan showed improved detection only for the thyroid gland compared to W32 scan (p=0.047). The AUROC for detection of irAE in the three target organs was highest when SUVX% was extracted from W16 scan and was 0.76 for lung, 0.53 for bowel and 0.81 for thyroid. SUVX% extracted from W4 scan did not improve detection of irAE compared to W16 scan (lung: p = 0.54, bowel: p = 0.75, thyroid: p = 0.3, DeLong test), as well as compared to W32 scan in lungs (p = 0.32) and bowel (p = 0.3). CONCLUSIONS: Early time point 18F-FDG PET/CT at W4 did not lead to statistically significant earlier detection of irAE. However, organ 18F-FDG uptake as quantified by SUVX% proved to be a consistent QIB of irAE. To better assess the role of 18F-FDG PET/CT in irAE detection, the time evolution of 18F-FDG PET/CT quantifiable inflammation would be of essence, only achievable in multi centric studies.

Quantitative brain [18F]FDG PET beyond normal blood glucose levels.

Introduction SUV measurements from static brain [18F]FDG PET acquisitions are a commonly used tool in preclinical research, providing a simple alternative for kinetic modelling, which requires complex and time-consuming dynamic acquisitions. However, SUV can be severely affected by the animal handling and preconditioning protocols, primarily by those that may induce changes in blood glucose levels (BGL). Here, we aimed at developing and investigating the feasibility of SUV-based approaches for a wide range of BGL far beyond normal values, and consequently, to develop and validate a new model to generate standardized and reproducible SUV measurements for any BGL. Material and methods We performed dynamic and static brain [18F]FDG PET acquisitions in 52 male Sprague-Dawley rats sorted into control (n = 10), non-fasting (n = 14), insulin-induced hypoglycemia (n = 12) and glucagon-induced hyperglycemia (n = 16) groups. Brain [18F]FDG PET images were cropped, aligned and co-registered to a standard template to calculate whole-brain and regional SUV. Cerebral Metabolic Rate of Glucose (CMRglc) was also estimated from 2-Tissue Compartment Model (2TCM) and Patlak plot for validation purposes. Results Our results showed that BGL=100±6 mg/dL can be considered a reproducible reference value for normoglycemia. Furthermore, we successfully established a 2nd-degree polynomial model (C1=0.66E-4, C2=-0.0408 and C3=7.298) relying exclusively on BGL measures at pre-[18F]FDG injection time, that characterizes more precisely the relationship between SUV and BGL for a wide range of BGL values (from 10 to 338 mg/dL). We confirmed the ability of this model to generate corrected SUV estimations that are highly correlated to CMRglc estimations (R2= 0.54 2TCM CMRgluc and R2= 0.49 Patlak CMRgluc). Besides, slight regional differences in SUV were found in animals from extreme BGL groups, showing that [18F]FDG uptake is mostly directed toward central regions of the brain when BGLs are significantly decreased. Conclusion Our study successfully established a non-linear model that relies exclusively on pre-scan BGL measurements to characterize the relationship between [18F]FDG SUV and BGL. The extensive validation confirmed its ability to generate SUV-based surrogates of CMRglu along a wide range of BGL and it holds the potential to be adopted as a standard protocol by the preclinical neuroimaging community using brain [18F]FDG PET imaging.

[18F]FDG PET/CT Imaging Is Associated with Lower In-Hospital Mortality in Patients with Pyogenic Spondylodiscitis-A Registry-Based Analysis of 29,362 Cases.

BACKGROUND: While MRI is the primary diagnostic tool for the diagnosis of spondylodiscitis, the role of [18F]-fluorodeoxyglucose ([18F]FDG) PET/CT is gaining prominence. This study aimed to determine the frequency of [18F]FDG PET/CT usage and its impact on the in-hospital mortality rate in patients with spondylodiscitis, particularly in the geriatric population. METHODS: We conducted a Germany-wide cross-sectional study from 2019 to 2021 using an open-access, Germany-wide database, analyzing cases with ICD-10 codes M46.2-, M46.3-, and M46.4- ('Osteomyelitis of vertebrae', 'Infection of intervertebral disc (pyogenic)', and 'Discitis unspecified'). Diagnostic modalities were compared for their association with in-hospital mortality, with a focus on [18F]FDG PET/CT. RESULTS: In total, 29,362 hospital admissions from 2019 to 2021 were analyzed. Of these, 60.1% were male and 39.9% were female, and 71.8% of the patients were aged 65 years and above. The overall in-hospital mortality rate was 6.5% for the entire cohort and 8.2% for the geriatric subgroup (p < 0.001). Contrast-enhanced (ce) MRI (48.1%) and native CT (39.4%) of the spine were the most frequently conducted diagnostic modalities. [18F]FDG PET/CT was performed in 2.7% of cases. CeCT was associated with increased in-hospital mortality (OR = 2.03, 95% CI: 1.90-2.17, p < 0.001). Cases with documented [18F]FDG PET/CT showed a lower frequency of in-hospital deaths (OR = 0.58, 95% CI: 0.18-0.50; p = 0.002). This finding was more pronounced in patients aged 65 and above (OR = 0.42, 95% CI: 0.27-0.65, p = 0.001). CONCLUSIONS: Despite its infrequent use, [18F]FDG PET/CT was associated with a lower in-hospital mortality rate in patients with spondylodiscitis, particularly in the geriatric cohort. This study is limited by only considering data on hospitalized patients and relying on the assumption of error-free coding. Further research is needed to optimize diagnostic approaches for spondylodiscitis.

[18F]FDG PET/CT Integration in Evaluating Immunotherapy for Lung Cancer: A Clinician's Practical Approach.

The advent of immune checkpoint inhibitors (ICIs) has revolutionized the treatment paradigm of lung cancer, resulting in notable enhancements in patient survival. Nevertheless, evaluating treatment response in patients undergoing immunotherapy poses distinct challenges due to unconventional response patterns like pseudoprogressive disease (PPD), dissociated response (DR), and hyperprogressive disease (HPD). Conventional response criteria such as the RECIST 1.1 may not adequately address these complexities. To tackle this issue, novel response criteria such as the iRECIST and imRECIST have been proposed, enabling a more comprehensive assessment of treatment response by incorporating additional scans and considering the best overall response even after radiologic progressive disease evaluation. Additionally, [18F]FDG PET/CT imaging has emerged as a valuable modality for evaluating treatment response, with various metabolic response criteria such as the PERCIMT, imPERCIST, and iPERCIST developed to overcome the limitations of traditional criteria, particularly in detecting pseudoprogression. A multidisciplinary approach involving oncologists, radiologists, and nuclear medicine specialists is crucial for effectively navigating these complexities and enhancing patient outcomes in the era of immunotherapy for lung cancer. In this review, we delineate the key components of these guidelines, summarizing essential aspects for radiologists and nuclear medicine physicians. Furthermore, we provide insights into how imaging can guide the management of individual lung cancer patients in real-world multidisciplinary settings.

Imaging in Renal Cell Carcinoma Detection.

INTRODUCTION: Imaging in renal cell carcinoma (RCC) is a constantly evolving landscape. The incidence of RCC has been rising over the years with the improvement in image quality and sensitivity in imaging modalities resulting in "incidentalomas" being detected. We aim to explore the latest advances in imaging for RCC. METHODS: A literature search was conducted using Medline and Google Scholar, up to May 2024. For each subsection of the manuscript, a separate search was performed using a combination of the following key terms "renal cell carcinoma", "renal mass", "ultrasound", "computed tomography", "magnetic resonance imaging", "18F-Fluorodeoxyglucose PET/CT", "prostate-specific membrane antigen PET/CT", "technetium-99m sestamibi SPECT/CT", "carbonic anhydrase IX", "girentuximab", and "radiomics". Studies that were not in English were excluded. The reference lists of selected manuscripts were checked manually for eligible articles. RESULTS: The main imaging modalities for RCC currently are ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). Contrast-enhanced US (CEUS) has emerged as an alternative to CT or MRI for the characterisation of renal masses. Furthermore, there has been significant research in molecular imaging in recent years, including FDG PET, PSMA PET/CT, 99mTc-Sestamibi, and anti-carbonic anhydrase IX monoclonal antibodies/peptides. Radiomics and the use of AI in radiology is a growing area of interest. CONCLUSIONS: There will be significant change in the field of imaging in RCC as molecular imaging becomes increasingly popular, which reflects a shift in management to a more conservative approach, especially for small renal masses (SRMs). There is the hope that the improvement in imaging will result in less unnecessary invasive surgeries or biopsies being performed for benign or indolent renal lesions.

Impact of mediastinal tumor burden and lymphatic spread in locally advanced non-small-cell lung cancer: A secondary analysis of the multicenter randomized PET-Plan trial.

PURPOSE: The aim of this secondary analysis of the prospective randomized phase 2 PET-Plan trial (ARO-2009-09; NCT00697333) was to evaluate the impact of mediastinal tumor burden and lymphatic spread in patients with locally advanced non-small-cell lung cancer (NSCLC). METHODS: All patients treated per protocol (n = 172) were included. Patients received isotoxically dose-escalated chemoradiotherapy up to a total dose of 60-74 Gy in 30-37 fractions, aiming as high as possible while adhering to normal tissue constraints. Radiation treatment (RT) planning was based on an 18F-FDG PET/CT targeting all lymph node (LN) stations containing CT positive LNs (i.e. short axis diameter > 10 mm), even if PET-negative (arm A) or targeting only LN stations containing PET-positive nodes (arm B). LN stations were classified into echelon 1 (ipsilateral hilum), 2 (ipsilateral station 4 and 7), and 3 (rest of the mediastinum, contralateral hilum). The endpoints were overall survival (OS), progression-free survival (PFS), and freedom from local progression (FFLP). RESULTS: The median follow-up time (95 % confidence interval [CI]) was 41.1 (33.8 - 50.4) months. Patients with a high absolute number of PET-positive LN stations had worse OS (hazard ratio [HR] = 1.09; 95 % CI 0.99 - 1.18; p = 0.05) and PFS (HR = 1.12; 95 % CI 1.04 - 1.20; p = 0.003), irrespective of treatment arm allocation. The prescribed RT dose to the LNs did not correlate with any of the endpoints when considering all patients. However, in patients in arm B (i.e., PET-based selective nodal irradiation), prescribed RT dose to each LN station correlated significantly with FFLP (HR=0.45; 95 % CI 0.24-0.85; p = 0.01). Furthermore, patients with involvement of echelon 3 LN stations had worse PFS (HR = 2.22; 95 % CI 1.16-4.28; p = 0.02), also irrespective of allocation. CONCLUSION: Mediastinal tumor burden and lymphatic involvement patterns influence outcome in patients treated with definitive chemoradiotherapy for locally advanced NSCLC. Higher dose to LNs did not improve OS, but did improve FFLP in patients treated with PET-based dose-escalated RT.

Impact of multidisciplinary Endocarditis Team on management of infective endocarditis.

Infective Endocarditis (IE) is a complex, life-threatening disease. The aim of the present study was to evaluate the impact of the Endocarditis-Team on management of IE. This observational study conducted at a university hospital (2015‒22), included adult patients with IE. The study period was divided in two periods: before (pre-Endocarditis-Team; pre-ET) and after the establishment of the Endocarditis-Team (post-Endocarditis-Team; post-ET) on January 2018. Among 505 IE episodes (187 in pre-Endocarditis-Team, 318 in post-ET period), 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography was more commonly used in post-ET period (14 % vs. 28 %; p < 0.001). Overall, thirty-day and one-year mortality were 14 % and 27 %, respectively; no difference was observed between the two periods. In post-ET period, the administration of 4-weeks, rather than 6-weeks, of intravenous antimicrobial treatment was higher than in the post-ET period (15 % vs. 45 %; p < 0.001). Indication for surgery was present in 115 (61 %) patients in pre-ET and in 153 (48 %) in the post-ET period. In post-ET period, among patients with indication, valve surgery was more frequently performed (66 % vs. 78 %; p = 0.038). Such difference was due to a higher acceptance of operative indication by the cardiac surgeon (69 % vs. 94 %; p = 0.013). The observed increase in number of patients benefiting from cardiac surgery in the post-ET period led to a decrease of subsequent embolic events, since among patients with operative indication (n = 268), new embolic events after the establishment of the indication were more common in the pre-ET period compared to post-ET (23 % vs. 12 %; p = 0.033). After the implementation of the multidisciplinary Endocarditis-Team we observed several improvements in the general management of IE patients.

18F-FDG PET/CT biomarkers as predictors of long term outcomes and survival rates in patients with high risk malignant pulmonary masses/nodules treated with stereotactic ablative radiotherapy.

INTRODUCTION: Stereotactic ablative body radiotherapy (SABR) is a standard treatment option for patients with malignant pulmonary masses (including primary and metastatic lesions) who are unfit for surgery or who are medically operable but refuse surgery. Flourine-18 flurodeoxyglucose positron emission tomography (18F-FDG PET) volumetric metabolic parameters, i.e., metabolic tumour volume (MTV) and total lesion glycolysis (TLG) play an important role in assessing the biological characteristics of some tumours and its role as potential prognostic factors has also been introduced. OBJECTIVES: The aim of this retrospective study is to assess the value of baseline metabolic volumetric parameters as prognostic imaging biomarkers in patients with pulmonary masses/nodules treated with SABR. METHODS: 70 patients were included in this retrospective study (39 male and 31 female, age range 47-91 years, mean 76 years). Standardized uptake value (SUVmax), SUVmean, MTV and TLG for all the patients were calculated on baseline 18F-FDG PET/CT. Patient outcome was divided into 3 categories free of disease, stable disease and disease progression. RESULTS: There was no significant statistical difference in the SUVmax and SUVmean in all the three categories. Mean SUVmax ranges from 7.13 to 8.08 with its highest value in the stable disease and lowest value in the progressive disease categories. Similarly, the average SUVmean was 4.9 in the free of disease category and 4.68 in the progressive disease category. MTV and TLG were low in the free of disease and the highest in progressive disease. MTV increased from 2.25 cm3 in free of disease category to 3.23 cm3 and 7.29 cm3 in stable disease and progressive disease, respectively. TLG has increased from 11.7 in the disease-free survival category to 18.77 and 40.39 in the stable and progressive disease, respectively. Patients with low MTV had longer overall survival (OS) than patients with high MTV (37 months versus 27 months, p value = 0. 0018). In addition, OS was longer in patients with low TLG (36 months versus 24 months, p value = 0.016). CONCLUSIONS: TLG and MTV are more useful than SUVmax and SUVmean for predicting outcome, OS and progression-free survival (PFS) in patients receiving SABR. The TLG and MTV measurement on 18F-FDG PET imaging may be routinely recommended in baseline 18F-FDG PET/CT prior to SABR.