Fluorodeoxyglucose Positron Emission Tomography Research Articles

Advancements and Challenges in the Management of Prosthetic Valve Endocarditis: A Review

Prosthetic valve endocarditis (PVE) is the medical term used to describe a focus of infection involving a valvular substitute within the heart. It is a significant concern in the field of cardiology, and the epidemiology of PVE has seen notable developments over the last five decades. The disease currently affects an older demographic and is becoming increasingly prevalent in patients with transcatheter-implanted valves. It is imperative that we urgently address the significant challenges posed by PVE. It is a disease that has a wide range of potential aetiologies, clinical presentations, and courses. In developed countries, Staphylococcus aureus is now the predominant causative organism, resulting in an aggressive form of disease that frequently afflicts vulnerable or elderly populations. However, it is clear that Enterococcus species present a significant challenge in the context of PVE following TAVR procedures, given their elevated prevalence. The 2023 Duke/International Society for Cardiovascular Infectious Diseases infective endocarditis diagnostic criteria now include significant developments in microbiological and image-based techniques for diagnostic purposes, specifically the incorporation of fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography. These developments unequivocally enhance the diagnostic sensitivity for PVE, while maintaining the specificity. They do so in accordance with the results of studies conducted specifically for the purpose of validation. The lack of rigorous scientific studies and a shortage of funding and resources for research have led to a significant gap in our understanding. Randomized controlled trials could provide invaluable insight and guidance for clinical practice, but they are missing, which represents a major gap. It is clear that there is an urgent need for more research. PVE is a life-threatening condition that must be handled by a multidisciplinary endocarditis team at a cardiac centre in order to improve outcomes. The emergence of innovative surgical techniques has empowered clinicians to steer more patients away from surgical procedures, despite the presence of clear indications for them. A select group of patients can now complete parenteral or oral antimicrobial treatment at home. Additionally, antibiotic prophylaxis is the best option for individuals with prosthetic valves who are going to have invasive dental procedures. These individuals should be given antibiotics beforehand.

Elevated locus coeruleus metabolism provides resilience against cognitive decline in preclinical Alzheimer's disease.

Alterations in locus coeruleus' (LC) metabolic turnover are associated with Alzheimer's disease (AD)-pathology and cognitive impairment. However, the evolution of these changes across disease stages and their functional relevance remains unknown. We examined associations of [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) -derived LC metabolism with clinical diagnostic status, cerebrospinal fluid (CSF) -based AD biomarkers of AD pathology, and cognitive decline in Alzheimer's Disease Neuroimaging Initiative (ADNI) participants (n=604). FDG-PET-derived LC metabolism was elevated in the earliest preclinical stages and lower in later disease stages. Higher LC metabolism was associated with attenuated memory decline in preclinical stages, particularly in those with low CSF Aβ42, but not in AD patients with cognitive impairment. Higher locus coeruleus [18F]-FDG-PET-derived signal in the early preclinical stages of AD can confer cognitive resilience and may reflect increased metabolic activity, whereas later stages are characterized by lower LC FDG-PET-derived signal, possibly due to neurodegeneration. LC FDG-PET signal is lower in Alzheimer's disease (AD) patients. LC FDG-PET signal is higher in the preclinical stage of AD. We observed less memory decline in those with higher LC FDG-PET signal. Higher LC FDG-PET signal conferred cognitive resilience in preclinical AD.

A deep learning method for the recovery of standard-dose imaging quality from ultra-low-dose PET on wavelet domain.

Recent development in positron emission tomography (PET) dramatically increased the effective sensitivity by increasing the geometric coverage leading to total-body PET imaging. This encouraging breakthrough brings the hope of ultra-low dose PET imaging equivalent to transatlantic flight with the assistance of deep learning (DL)-based methods. However, conventional DL approaches face limitations in addressing the heterogeneous domain of PET imaging. This study aims to develop a wavelet-based DL method capable of restoring high-quality imaging from ultra-low-dose PET scans. In contrast to conventional DL techniques that denoise images in the spatial domain, we introduce WaveNet, a novel approach that inputs wavelet-decomposed frequency components of PET imaging to perform denoising in the frequency domain. A dataset comprising total-body 18F -FDG PET images of 1447, acquired using total-body PET scanners including Biograph Vision Quadra (Siemens Healthineers) and uEXPLORER (United Imaging) in Bern and Shanghai, was utilized for developing and testing the proposed method. The quality of enhanced images was assessed using a customized scoring system, which incorporated weighted global physical metrics and local indices. Our proposed WaveNet consistently outperforms the baseline UNet model across all levels of dose reduction factors (DRF), with greater improvements observed as image quality decreases. Statistical analysis (p < 0.05) and visual inspection validated the superiority of WaveNet. Moreover, WaveNet demonstrated superior generalizability when applied to two cross-scanner datasets (p < 0.05). WaveNet developed with total-body PET scanners may offer a computational-friendly and robust approach to recover image quality from ultra-low-dose PET imaging. Its adoption may enhance the reliability and clinical acceptance of DL-based dose reduction techniques.

Presynaptic terminal integrity is associated with glucose metabolism in Parkinson's disease.

To investigate the relationship of synaptic loss with glucose metabolism and dopaminergic transporters in Parkinson's disease (PD) patients. A total of 16 patients with PD and 11 age-matched healthy controls underwent positron emission tomography (PET) with the tracers [18F]SynVesT-1, a ligand for the presynaptic terminal marker synaptic vesicle protein 2A (SV2A), and FDG. PD patients also underwent PET with the dopamine transporter (DAT) ligand [18F]FP-CIT. The difference in synaptic density between PD patients and age-matched normal controls(NCs) was determined in the selected regions of interest, and the correlations of the [18F]SynVesT-1 PET SUVRs with [18F]FP-CIT PET SUVRs and [18F]FDG PET SUVRs were evaluated. Compared with that in the NC group, the synaptic density in the caudate region was significantly lower in the PD group (SUVR: 2.51 ± 0.36 vs. 3.18 ± 0.32, p < 0.001), especially in the pre-commissural caudate and post-commissural caudate (SUVR: 2.42 ± 0.29 vs. 2.63 ± 0.32, p < 0.01; 0.76 ± 0.31 vs. 0.97 ± 0.33, p < 0.001). A reduced synaptic density was significantly correlated with DAT (r = 0.61, p < 0.001) and glucose metabolism (r = 0.73, p < 0.001) in the post-commissural caudate. In the post-commissural regions of the caudate, there was a partial mediating effect of synaptic density on the relationship between glucose metabolism and DAT availability (indirect effect: β4 = 0.039, p = 0.024). [18F]SynVesT-1 binds specifically to SV2A, reflecting synaptic density, and there is a positive correlation metabolic pattern related to the changes reflected by [18F]SynVesT-1 and [18F]FDG.

The prognostic value of pretreatment [18F]FDG PET/CT parameters in esophageal cancer: a meta-analysis.

This study aims to evaluate the prognostic implications of pretreatment [18F]FDG-PET metrics in esophageal cancer patients through a meta-analysis of the existing literature. We carefully searched electronic databases, including PubMed and Embase, from inception to April 1, 2024, to identify studies describing the prognostic value of pretreatment PET metrics for advanced esophageal cancer. Clinical endpoints examined were overall survival (OS), recurrence-free survival (RFS)/disease-free survival (DFS), and progression-free survival (PFS). Hazard ratios (HRs) for PFS and OS were taken directly from the original reports. Forty-seven publications, including 5504 patients, were included in our analysis. OS and PFS were analyzed in 31 and nine studies, respectively, and DFS/RFS was analyzed in 16 studies. The comprehensive pooled analysis revealed significant associations between metabolic parameters derived from positron emission tomography (PET) imaging and clinical outcomes. Expressly, the pooled HR indicated that patients with higher SUVmax were significantly associated with poor PFS (HR: 1.06; 95% CI: 1.01-1.12, p = 0.011) and poor RFS/DFS (HR: 1.09; 95% CI: 1.02-1.18, p = 0.019). Patients with higher SUVmean were significantly associated with poorer OS (HR: 1.07; 95% CI: 1.01-1.14, p = 0.025). High MTV was significantly associated with inferior OS (HR: 1.02; 95% CI: 1.00-1.05, p = 0.049). High TLG was significantly associated with poorer RFS/DFS (HR: 2.02; 95% CI: 1.11-3.68, p = 0.022). This study unveiled pretreatment FDG-derived parameters as valuable prognostic indicators in assessing esophageal cancer outcomes. Specifically, SUVmax is associated with PFS and RFS/DFS. SUVmean and MTV were correlated with OS, and TLG was only associated with RFS/DFS. Question Inconsistent findings on the prognostic value of pretreatment [18F]FDG PET parameters in esophageal cancer require comprehensive analysis to clarify their role in outcome prediction. Findings Higher pretreatment [18F]FDG-PET metrics (SUVmax, SUVmean, MTV, TLG) are associated with poor survival outcomes, emphasizing their potential value in enhancing prognostic assessments for esophageal cancer. Clinical relevance This study highlights the prognostic significance of pretreatment [18F]FDG-PET metrics in esophageal cancer, providing valuable insights for patient outcome prediction and potentially guiding personalized treatment strategies.

Identification of mild cognitive impairment using multimodal 3D imaging data and graph convolutional networks

Objective.Mild cognitive impairment (MCI) is a precursor stage of dementia characterized by mild cognitive decline in one or more cognitive domains, without meeting the criteria for dementia. MCI is considered a prodromal form of Alzheimer's disease (AD). Early identification of MCI is crucial for both intervention and prevention of AD. To accurately identify MCI, a novel multimodal 3D imaging data integration graph convolutional network (GCN) model is designed in this paper.Approach.The proposed model utilizes 3D-VGGNet to extract three-dimensional features from multimodal imaging data (such as structural magnetic resonance imaging and fluorodeoxyglucose positron emission tomography), which are then fused into feature vectors as the node features of a population graph. Non-imaging features of participants are combined with the multimodal imaging data to construct a population sparse graph. Additionally, in order to optimize the connectivity of the graph, we employed the pairwise attribute estimation （PAE） method to compute the edge weights based on non-imaging data, thereby enhancing the effectiveness of the graph structure. Subsequently, a population-based GCN integrates the structural and functional features of different modal images into the features of each participant for MCI classification.Main results.Experiments on the AD Neuroimaging Initiative demonstrated accuracies of 98.57%, 96.03%, and 96.83% for the normal controls (NC)-early MCI (EMCI), NC-late MCI (LMCI), and EMCI-LMCI classification tasks, respectively. The AUC, specificity, sensitivity, and F1-score are also superior to state-of-the-art models, demonstrating the effectiveness of the proposed model. Furthermore, the proposed model is applied to the ABIDE dataset for autism diagnosis, achieving an accuracy of 91.43% and outperforming the state-of-the-art models, indicating excellent generalization capabilities of the proposed model.Significance.This study demonstratesthe proposed model's ability to integrate multimodal imaging data and its excellent ability to recognize MCI. This will help achieve early warning for AD and intelligent diagnosis of other brain neurodegenerative diseases.

Alpha-fetoprotein-producing intramucosal gastric cancer found during examination of metastatic lymph nodes.

Endoscopic resection has been applied as an absolute indication for early gastric cancer showing intramucosal cancer ≤ 2cm in diameter, differentiated-type adenocarcinoma without ulcerative findings. We describe the case of a 76-year-old man who underwent radical gastrectomy for alpha-fetoprotein-producing gastric cancer, in which the depth of invasion was clinically diagnosed as T1a after lymph node metastases were detected. Upper gastrointestinal endoscopy revealed a type 0-IIc tumor nearly 10mm in diameter at the antrum. Computed tomography showed a 47-mm nodule along the common hepatic artery and a 22-mm nodule in the infrapyloric area. Both were pathologically confirmed as adenocarcinoma by endoscopic ultrasound-guided aspiration. No evidence of malignancy elsewhere was seen on 18F-fluorodeoxyglucose positron emission tomography. Serum alpha-fetoprotein level was elevated. Postoperatively, microscopic examination revealed moderately differentiated adenocarcinoma confined to the mucosal layer without lymphovascular involvement. Immunohistochemical examination for alpha-fetoprotein revealed that the metastatic nodes were positive despite the primary tumor being negative. The patient died of exacerbation of myelodysplastic syndrome 5years 8months postoperatively with no recurrence. Our experience suggests the need for further studies to validate whether the indications for endoscopic resection can apply to alpha-fetoprotein-producing gastric cancer in the same manner as to conventional gastric cancer.

Role of 18-Fluorine Fluoro-deoxy Glucose Positron Emission Tomography (FDG-PET/CT scan) in Suspected Relapsed Ovarian Cancer; an Institutional Experience.

Objectives: To determine the role of 18-Fluorine Fluoro-deoxy glucose Positron Emission Tomography (18F FDG-PET/CT scan) in suspected relapsed ovarian cancer patients. Study Design: Cross-sectional study. Place and Duration of Study: Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore Pakistan, from Jan 2010 to Dec 2017. Methodology: A total of 964 patients of epithelial ovarian carcinoma who had histologically proven ovarian cancer diagnosed from January 2010 until December 2017 were reviewed. 70 patients on surveillance who had FDG-PET/CT scan for suspected relapse were included in our study. Data collected from the digital Hospital Information System after Institutional review board approval. Results: Average age for our study group was 48.6 years ± 11.4 SD. Serous pathology was predominant in 47/70(67.1%) patients followed by Endometroid (14.3%). FDG-PET/CT scan changed the stage in 30% patients. Sensitivity, specificity, positive predictive value, and negative predictive value of FDG-PET/CT were 96%, 72%, 89% and 88% respectively while it is 92%, 76%, 90%, and 80% respectively for conventional CT scan. Average Cancer antigen-125 (CA-125) at suspected relapse is 290. 21 patients (75%) showed FDG avid disease on PET scan in whom CA-125 was normal. Conclusion: PET scan has better negative predictive value than conventional CT scan to detect relapse in ovarian cancer, its overall sensitivity is comparable to contrast-enhanced CT scan. CA-125 is not a reliable marker for the detection of relapse in ovarian cancer patients.

Solitary fibrous tumor of the gallbladder: a case report

BackgroundPrimary solitary fibrous tumors (SFTs) of the gallbladder are rare. Here, we report the case of a patient who underwent surgical treatment for a primary SFT originating in the gallbladder.Case presentationA 48-mm gallbladder tumor was detected in a 70-year-old man using abdominal ultrasonography at a primary hospital, and he was subsequently referred to our department. A 50-mm enhanced tumor in the gallbladder was identified using computed tomography. Magnetic resonance imaging revealed a smooth-marginated tumor with hyperintensity on T2-weighted imaging. 18F-Fluorodeoxyglucose positron emission tomography confirmed high-level fluorodeoxyglucose uptake in the gallbladder tumor in the early phase without increasing uptake in the later phase. Surgical resection was planned to evaluate the tumor diagnosis. Initially, we performed open cholecystectomy with wedge resection of the gallbladder bed. Intraoperative pathological examination suggested gallbladder cancer; therefore, we performed radical surgery, including resection of the common bile duct, extended radical lymphadenectomy, and choledochojejunostomy. Ultimately, the final pathological examination revealed an SFT originating from the gallbladder with a negative surgical margin. Postoperatively, the patient developed bile leakage that was treated with tube drainage. The patient recovered satisfactorily and was discharged on postoperative day 20. At 24 months postoperatively, the patient was in good general condition without recurrence.ConclusionsWe report a rare case of a primary SFT originating in the gallbladder. Clinicians should be aware that SFT can be found in the gallbladder, and when it is difficult to make a preoperative diagnosis, surgical treatment should be considered.

A Case of Cardiomyopathy Associated with CD36 Deficiency: Role of 18F-Fluorodeoxyglucose Positron Emission Tomography in the Diagnosis.

We herein report a patient with type I CD36 deficiency. The patient was initially suspected of having isolated cardiac sarcoidosis based on the presence of non-sustained ventricular tachycardia, delayed myocardial enhancement on magnetic resonance imaging (MRI), and diffuse accumulation of 18F-fluorodeoxyglucose (18F-FDG) on cardiac positron emission tomography (PET). Our findings suggest that the diagnosis of cardiomyopathy associated with CD36 deficiency is often missed, highlighting the importance of a differential diagnosis of isolated cardiac sarcoidosis.

Intrahepatic Cholangiocarcinoma Presenting as an Incidentaloma on F-18 PYL PSMA PET/CT

AbstractCholangiocarcinoma is an aggressive malignancy arising from the biliary tract epithelium with rising incidence and mortality. Imaging commonly used for diagnostic workup includes computed tomography (CT) scan and magnetic resonance imaging (MRI). Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) scans can be used for investigating equivocal findings on radiographic imaging. Prostate-specific membrane antigen (PSMA) is known to be highly expressed in prostate adenocarcinoma, allowing it to be leveraged as a target for both imaging and radioligand therapy in prostate cancer. However, PSMA is also commonly expressed in other malignancies such as breast cancer, thyroid carcinomas, and head and neck malignancies, which increase the chances of their incidental diagnosis on PSMA PET scans. Biliary tract cancers, including cholangiocarcinoma, are not commonly expected to be incidentally diagnosed on PSMA PET imaging. Here, we describe the case of a patient with known prostate adenocarcinoma who was later incidentally diagnosed with advanced intrahepatic cholangiocarcinoma on PSMA PET/computed tomography (CT). This case highlights the unexpected finding of cholangiocarcinoma on PSMA PET/CT and suggests further investigation into the role of PSMA PET in diagnosing ambiguous cases of cholangiocarcinoma and its potential theranostic applications.

A Phase 2 study of acimtamig (AFM13) in patients with CD30-positive, relapsed or refractory peripheral T-cell lymphomas.

Patients with relapsed or refractory (R/R) peripheral T-cell lymphoma (PTCL) generally have poor prognoses and limited treatment options. This study evaluated the efficacy of a novel CD30/CD16A bispecific innate cell engager, acimtamig (AFM13), in patients with R/R PTCL. Patients included those with CD30 expression in ≥1% of tumor cells and who were R/R following ≥1 prior line of systemic therapy. Acimtamig (200 mg) was administered once weekly in 8-week cycles. The primary endpoint was overall response rate (ORR) by fluorodeoxyglucose-positron emission tomography per independent review committee; secondary and exploratory endpoints included duration of response (DoR), safety, progression-free survival, and overall survival. The ORR in 108 patients was 32.4% (95% CI: 23.7, 42.1) with a complete response rate of 10.2% (95% CI: 5.2, 17.5); median DoR was 2.3 months (95% CI: 1.9, 6.5). Patients with R/R angioimmunoblastic T-cell lymphoma exhibited the greatest number of responses (53.3% [95% CI: 34.3, 71.7]). Responses were independent of CD30 expression level, prior brentuximab vedotin treatment, or steroid premedication. Acimtamig exhibited a tolerable safety profile; the most common treatment-related adverse events were infusion-related reactions in 27 patients (25.0%) and neutropenia in 11 patients (10.2%). No cases of cytokine release syndrome or acimtamig-related deaths were reported. Despite exhibiting promising clinical activity and tolerable safety in a heavily pretreated PTCL population, the study did not meet the criteria for the primary endpoint. The promising clinical efficacy observed warrants further investigation, and development of acimtamig for patients with R/R CD30+ lymphomas continues in combination with allogeneic natural killer cells.

Extracerebral Normalization of 18F-FDG PET Imaging Combined with Behavioral CRS-R Scores Predict Recovery from Disorders of Consciousness.

Identifying patients likely to regain consciousness early on is a challenge. The assessment of consciousness levels and the prediction of wakefulness probabilities are facilitated by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET). This study aimed to develop a prognostic model for predicting 1-year postinjury outcomes in prolonged disorders of consciousness (DoC) using 18F-FDG PET alongside clinical behavioral scores. Eighty-seven patients with prolonged DoC newly diagnosed with behavioral Coma Recovery Scale-Revised (CRS-R) scores and 18F-FDG PET/computed tomography (18F-FDG PET/CT) scans were included. PET images were normalized by the cerebellum and extracerebral tissue, respectively. Images were divided into training and independent test sets at a ratio of 5:1. Image-based classification was conducted using the DenseNet121 network, whereas tabular-based deep learning was employed to train depth features extracted from imaging models and behavioral CRS-R scores. The performance of the models was assessed and compared using the McNemar test. Among the 87 patients with DoC who received routine treatments, 52 patients showed recovery of consciousness, whereas 35 did not. The classification of the standardized uptake value ratio by extracerebral tissue model demonstrated a higher specificity and lower sensitivity in predicting consciousness recovery than the classification of the standardized uptake value ratio by cerebellum model. With area under the curve values of 0.751 ± 0.093 and 0.412 ± 0.104 on the test sets, respectively, the difference is not statistically significant (P = 0.73). The combination of standardized uptake value ratio by extracerebral tissue and computed tomography depth features with behavioral CRS-R scores yielded the highest classification accuracy, with area under the curve values of 0.950 ± 0.027 and 0.933 ± 0.015 on the training and test sets, respectively, outperforming any individual mode. In this preliminary study, a multimodal prognostic model based on 18F-FDG PET extracerebral normalization and behavioral CRS-R scores facilitated the prediction of recovery in DoC.

Peri-ictal yawning: A potential lateralizing sign in temporal lobe epilepsy.

The primary objective of this retrospective analysis was to evaluate the incidence and lateralization value of peri-ictal yawning (PY) in people with temporal lobe epilepsy (TLE). PY has only occasionally been reported as a manifestation of focal epilepsy. We aimed to determine whether PY could serve as an indicator to help lateralize seizure onset during epileptic seizures. Among 236 consecutive TLE patients admitted for video-EEG monitoring, we analyzed the clinical characteristics, along with scalp video-EEG, magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET), Wada test, and stereo EEG (SEEG) in patients with PY. Among the 236 patients, 26 (11.0%) exhibited PY, and 36 of 1018 recorded seizures (3.5%) were associated with PY. Of the 26 patients with PY, 19 (73.1%) had non-dominant TLE, while 7 (26.9%) had dominant TLE. The majority of these patients presented with staring, arrest, and automatisms during their seizures with accompanying vegetative signs. PY occurred either during the ictal or postictal phase in all patients. Exception for 10 seizures (10/36, 27.8%) at the early stage (less than 25% total duration), PY was primarily linked to the late ictal and postictal phases. Surgical intervention was performed in 12 patients, 9 of whom (75%) achieved seizure freedom (Engel class I), with 7 of these 9 (77.8%) having non-dominant TLE. Yawning is a physiological phenomenon typically not associated with epilepsy. The present series suggests that PY is relatively uncommon in TLE, but may represent a rare vegetative sign, particularly in cases with non-dominant TLE. Further investigation with a larger cohort of surgically confirmed cases and using intracranial EEG is essential to deepen our understanding of this phenomenon. Yawning is a typical physiological response that is generally not linked to epilepsy. However, it can occasionally indicate seizure activity, particularly in TLE. PY happens more often observed in non-dominant TLE and usually occurs in the later stages of a seizure or just after it. It may hold potential as a lateralizing marker in TLE.

A model of lymphocryptovirus-associated post-transplant lymphoproliferative disorder in immunosuppressed Mauritian cynomolgus macaques.

Immunocompromised individuals are at risk for developing lymphocryptovirus-associated lymphoproliferative diseases, such as Epstein Barr virus (EBV)-associated B cell lymphomas and post-transplant lymphoproliferative disorder (PTLD). We previously reported development of cynomolgus lymphocryptovirus (CyLCV)-associated PTLD in Mauritian cynomolgus macaques (MCMs) undergoing hematopoietic stem cell transplantation (HSCT), which mirrored EBV-PTLD in transplant patients. Here, we sought to develop a MCM model of lymphocryptovirus-associated lymphoproliferative disease in immunosuppressed MCMs without HSCT. Five simian immunodeficiency virus (SIV)-infected, CD8α+ cell-depleted MCMs received an infusion of autologous B-lymphoblastoid cells transformed with CyLCV, followed by varying degrees of immunosuppression. Four of five infused macaques developed masses coincident with increasing CyLCV plasma viremia, and necropsies confirmed the presence of multicentric lymphomas, which most commonly manifested in lymph nodes, gastrointestinal tract, adrenal glands, and pancreas. Affected tissues harbored neoplastic lymphocytes double-positive for CD20 and CyLCV EBNA2 antigen, large frequencies of proliferating B cells, and high levels of cell-associated CyLCV DNA. In addition, longitudinal 18F-fluorodeoxyglucose positron-emission tomography (18F-FDG PET) of one MCM successfully detected lymphoproliferative disease in the adrenal glands prior to clinical signs of disease. These data demonstrate successful induction of lymphocryptovirus-associated PTLD-like disease in 4 of 5 MCMs, and thus support the use of MCMs as a preclinical NHP model of EBV-associated lymphoproliferative disease that could be employed to test novel diagnostic and therapeutic modalities.

Agreement between Cerebrospinal Fluid Biomarkers, Brain 18-Fluorodeoxyglucose PET, and Clinical Diagnosis in Older Adults with Cognitive Impairment.

Background: Clinical practice has advanced toward a combined diagnostic approach that involves clinical criteria and biological markers for Alzheimer's disease (AD) and other dementias. Objective: To establish the level of diagnostic agreement between an initial clinical diagnosis and cerebrospinal fluid (CSF) and [18F]-fluorodeoxyglucose (FDG)-positron emission tomography (PET) biomarkers in a cohort of patients from a memory clinic. Methods: This is a observational, retrospective, cohort study conducted at an outpatient memory clinic. Between July 2018 and September 2023, data from adults' ≥ 55 years with a mild cognitive impairment or dementia diagnosis without etiological diagnosis were obtained, complemented with the evaluation of biomarkers in CSF and [18F] FDG-PET biomarker assessment were included. Kappa coefficients (κ) were used to establish the level of agreement between CSF and [18F] FDG-PET results. Results: Seventy-seven patients had an available [18F] FDG-PET scan, and 25 (32.5%) had both biomarkers. We observed a fair-to-moderate diagnostic agreement between patients' initial and their final diagnosis in the presence of CSF (κ = 0.233, 95% confidence interval [CI]: -0.099-0.566) and [18F] FDG-PET (κ = 0.451, 95% CI: 0.277-0.625, p < 0.001) results. The Kappa value for diagnostic concordance between [18F] FDG-PET and CSF to differentiate between AD and other dementias was 0.733 (95% CI: 0.425-1.000, p < 0.005). Conclusion: This study demonstrates good agreement between the CSF and FDG-PET biomarkers to differentiate AD from other dementias. (Rev Invest Clin. 2024;76(5):230-7).

Perinatal exposure to PBDE-47 decreases brain glucose metabolism in male adult rats: Associations with shifts in triiodothyronine and neurobehavior

BackgroundThe brominated flame retardant 2, 2′, 4, 4′-tetrabromodiphenyl ether (PBDE-47) is well known as a developmental neurotoxicant, yet the underlying mechanisms remain elusive. Increasing evidence has demonstrated that brain glucose metabolism perturbation plays a role in neural impairments. Nevertheless, whether this disturbance is involved in PBDE-47-induced neurotoxicity remains unknown. ObjectivesTo explore the impacts of perinatal PBDE-47 exposure on brain glucose metabolism, and its link to thyroid hormones (THs) levels as well as neurobehavioral changes. MethodsFemale Sprague-Dawley rats were orally exposed to PBDE-47 at environmentally relevant levels (0.1, 1.0, and 10.0 mg/kg bw) from pre-pregnancy through weaning of offspring. The male offspring were continued to raise to 88 days after birth for follow-up experiments. Morris water maze and Open field tests were performed to assess the neurobehavioral alterations. The brain glucose metabolism was evaluated using 18F-labeled fluorodeoxyglucose (18F-FDG) positron emission tomography. Serum THs levels were measured via enzyme-linked immunosorbent assay. ResultsPerinatal exposure to PBDE-47 induced neurobehavioral impairments in adult male rats as evidenced by learning and memory impairments, hyperactivity and anxiety-like behavior. Moreover, positron emission tomography showed that the glucose metabolism in the whole and the specific brain regions were markedly declined. Interestingly, variations in brain glucose metabolism were associated with the increased serum triiodothyronine (T3) levels, and both were linked to neurobehavioral disorders. ConclusionExposure to environmentally related levels of PBDE-47 at critical developmental stages lowers glucose metabolism in the whole brain and in various brain regions, which is associated with behavioral and cognitive deficits in adult male rats. Moreover, the association may be influenced by the disturbance of T3 homeostasis.

Comparative accuracy of Mini-Linguistic State Examination, Addenbrooke's Cognitive Examination, and Depistage Cognitif de Quebec for the diagnosis of primary progressive aphasia.

Clinical diagnosis in primary progressive aphasia (PPA) is challenging. Recently, emphasis has been placed on the importance of screening evaluation. Three different screening tests that use different strategies based on the assessment of language (Mini-Linguistic State Examination, MLSE) or different cognitive domains (Addenbrooke's Cognitive Examination, ACE-III and Dépistage Cognitif de Québec, DCQ) have been proposed and independently validated. These tests aim to detect PPA and classify into the three main variants (non-fluent (nfvPPA), semantic (svPPA) and logopenic (lvPPA)). This study aims to evaluate and compare the diagnostic capacity of these three instruments in PPA. A cross-sectional study including 43 patients with PPA (nfvPPA (n = 19), svPPA (n = 8), and lvPPA (n = 16)) and 21 cognitively unimpaired controls was conducted. Clinical diagnoses were established based on an extensive multidisciplinary assessment including neuropsychological assessment, fluorodeoxyglucose-positron emission tomography, MRI, and cerebrospinal fluid biomarkers. Both PPA patients and controls completed the three tests (MLSE, ACE-III, and DCQ). Internal consistency was excellent for the three tests. The area under the curve for the diagnosis of PPA was 0.950 for MLSE, 0.953 for ACE-III, and 0.933 for DCQ. Correlations between the three tests were high. The MLSE, ACE-III, and DCQ tests obtained adequate levels of discrimination between the variants of PPA, with accuracies between 76-79%. This study confirms the validity of ACE-III, MLSE, and DCQ for the diagnosis of PPA and its variants. This suggests that detailed assessment of linguistic characteristics (MLSE) and non-linguistic features (DCQ, ACE-III) are relevant for the diagnosis and classification of PPA.

Imaging of Upper Tract Urothelial Carcinoma.

Upper tract urothelial carcinoma (UTUC) originates in the renal pelvis or ureters and typically affects elderly patients, with its incidence increasing over the past few decades. UTUC is a distinct clinical entity with more aggressive clinical behavior than that of lower tract urothelial carcinoma. Due to the significant challenge of acquiring an adequate tissue sample for biopsy, comprehensive risk stratification is required for treatment planning, including radical nephroureterectomy and kidney-sparing management. Imaging plays an important integrated role in risk assessment along with endoscopy and pathologic examination. Lifelong surveillance is required after treatment due to the high incidence of recurrent and metachronous tumors. Lynch syndrome is a frequently unrecognized genetic disorder associated with UTUC that warrants specific attention in patient management. UTUC may manifest with diverse imaging findings, including filling defects, wall thickening, and mass-forming lesions. CT urography is the preferred modality for diagnosis and staging or restaging of UTUC, with numerous technical variations. Efforts have been made to optimize image quality and radiation exposure. Due to its poor sensitivity for small lesions, use of MR urography is limited to special clinical scenarios (eg, when patients have contraindications to iodinated contrast agents). Fluorine 18 fluorodeoxyglucose PET helps to detect metastatic lesions. Image-guided biopsy may be considered for uncertain lesions. Radiologists need to be familiar with the imaging findings and their differential diagnoses. ©RSNA, 2024 Supplemental material is available for this article.

Dietary Intake Is Similar Among Adult Men with Different Levels of Cold-Induced Brown Adipose Tissue Activation.

Brown adipose tissue (BAT) activation has important metabolic health implications, yet the relationship between habitual dietary intake and BAT activity in humans remains to be fully understood. We compared dietary intake among adult men with (BATpositive, age: 34.8 ± 5.4 years, BMI: 28.2 ± 5.3 kg/m2, n = 12) and without (BATnegative, age: 39.1 ± 4.1 years, BMI: 31.1 ± 6.7 kg/m2, n = 11) cold-induced BAT activation. Activation of BAT was measured immediately following 2 h of cold exposure using 18F fluorodeoxyglucose positron emission tomography and computed tomography reported as maximum standardized uptake (SUVmax). Participants categorized as BATpositive had an SUVmax > 1.5 g/mL that was normalized to lean body mass (SUVlean) for analysis. Shivering intensity was recorded every 15 min during cold exposure and dietary intake was estimated from 7 consecutive 24 h dietary recalls. The BATnegative group was significantly older than the BATpositive group (p = 0.046). Although BATnegative participants consumed an average of 281.2 kcal/day more than BATpositive, there were no significant differences in dietary intake between groups (p ≥ 0.202). Further, no statistically significant associations between SUVlean and dietary intake among BATpositive participants were observed (p ≥ 0.175). Participants who shivered (n = 9) during cold exposure tended to be shorter (p = 0.056) and have a lower waist-to-hip ratio (p = 0.097) but did not differ in dietary intake (p ≥ 0.204) or BAT activity (p = 0.964) when compared to the non-shivering (n = 11) group. Our results indicate that BAT activity and shivering during cold exposure are more strongly related to variables such as age and body size or composition rather than habitual dietary intake. We conclude that habitual dietary intake likely has a negligible influence on BAT activity among adult men.