PSMA PET/CT in the Brazilian Unified Healthcare System reduces costs with futile salvage therapies in the management of cases of biochemical recurrence of prostate cancer.

Objective: To compare costs between treatment strategies employed prior to and after prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) via the Brazilian Unified Health Care System and their impact on the therapeutic management of biochemical recurrence of prostate cancer. Materials and Methods: The referring physicians were surveyed on their treatment intentions (strategies) at two different time points: prior to and after PSMA PET/CT. Cost comparison results are presented as median (IQR) for each of the two strategies. The shift in therapeutic management after PSMA PET/CT was also analyzed. Results: The study sample included 59 patients (mean age: 65.9 years). The PSMA PET/CT result was considered positive in 38 patients (64.4%) and was found to have an impact on the treatment strategy in for 36 patients (61.0%). Prior to PSMA PET/CT, salvage therapy (i.e., treatment with curative intent) was the intended treatment for most patients, and that was significantly less so after the examination (76.3% vs. 45.8%; p < 0.001). Conversely, a strategy involving systemic (i.e., palliative) therapy became more common after PSMA PET/CT (23.7% vs. 54.2%; p < 0.001). The after-PSMA PET/CT strategy presented higher overall costs than did the before-PSMA PET/CT strategy, in all scenarios evaluated. In all scenarios, nearly half of this cost difference was related to the cost of the PSMA PET/CT itself, the remainder being related to the new treatment choices that stemmed from knowledge of the PSMA PET/CT findings. Conclusion: For patients treated within the Brazilian Unified Health Care System, PSMA PET/CT presented higher costs in comparison with conventional imaging methods. Adding PSMA PET/CT to the workflow had an impact on therapeutic management, mainly representing a shift from futile curative treatments to systemic palliative ones. The amount of funds that could potentially be saved by not providing such futile treatments would suffice to evaluate roughly two patients with PSMA PET/CT scans for each futile treatment strategy avoided.

Objetivo: Comparar custos entre estratégias antes e após o exame de PET/CT-PSMA da perspectiva do Sistema Único de Saúde e seu impacto no manejo terapêutico para pacientes com recidiva bioquímica de câncer de próstata. Materiais e Métodos: Os médicos solicitantes informaram a intenção terapêutica em dois momentos: antes e após o exame. Os resultados de comparação de custo estão apresentados como medianas de custo (p25; p75). A mudança na intenção terapêutica também foi analisada. Resultados: O estudo envolveu 59 pacientes (idade média: 65,9 anos). A PET/CT-PSMA foi considerada positiva em 38 dos 59 pacientes (64.4%). O exame impactou a estratégia de tratamento para 36 pacientes (61%). Antes da obtenção das informações da PET/CT-PSMA, a terapia de resgate (i.e., com intenção curativa) era o tratamento sugerido para a maioria dos pacientes, e após o exame, reduziu significativamente (76,3% vs 45,8%; p < 0,001). Em contrapartida, a terapia sistêmica (i.e., paliativa) aumentou como intenção de tratamento após o exame (23,7% vs 54,2%; p < 0,001). A estratégia "após PET/CT-PSMA" apresentou maiores custos em relação à estratégia "antes da PET/CT-PSMA" nos cenários comparados. Cerca de metade da diferença de custos entre as duas estratégias foi relacionada aos custos do exame propriamente ditos, enquanto a outra metade foi relacionada às novas escolhas de tratamento a partir do exame. Conclusão: Oferecer a PET/CT-PSMA no Sistema Único de Saúde apresentou maiores custos em relação à estratégia com métodos de imagem convencionais e impactou o manejo terapêutico, pelo favorecimento de tratamentos sistêmicos paliativos no lugar de tratamentos curativos fúteis. A quantidade de recursos que poderiam ser poupados ao evitar tratamentos fúteis seria suficiente para avaliar aproximadamente dois pacientes com exames de PET/CT-PSMA para cada estratégia de tratamento fútil evitada.

Imaging assessment of prostate cancer recurrence: advances in detection of local and systemic relapse.

Prostate cancer (PCa) relapse, defined either by persistent PSA levels (after RP) or biochemical recurrence (BCR), is a common occurrence. The imaging evaluation of patients experiencing PCa relapse has undergone significant advancements in the past decade, notably with the introduction of new Positron Emission Tomography (PET) tracers such as Prostate-specific membrane antigen (PSMA), and the progress in functional Magnetic Resonance Imaging (MRI). This article will explore the role of traditional imaging, the evolution of MRI towards the development of the Prostate Magnetic Resonance Imaging for Local Recurrence Reporting (PI-RR) scoring system, and how next-generation imaging is enhancing diagnostic accuracy in the setting of PCa relapse, which is essential for adopting personalized strategies that may ultimately impact outcomes.

Comparative evaluation of machine learning models in predicting overall survival for nasopharyngeal carcinoma using 18F-FDG PET-CT parameters.

PURPOSE: The objective of this study is to assess the prognostic efficacy of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET-CT) parameters in nasopharyngeal carcinoma (NPC) and identify the best machine learning (ML) prognostic model for NPC patients based on these 18F-FDG PET/CT parameters and clinical variables. METHOD: A cohort of 678 patients diagnosed with NPC between 2016 and 2020 was analyzed in this study. The model was constructed using four advanced ML algorithms, namely Random Forest (RF), Extreme Gradient Boosting (XGBoost), Least Absolute Shrinkage and Selection Operator (LASSO), and multifactor COX step-up regression. Statistical significance of the models was assessed using Kaplan-Meier (K-M) curves, with a significance level established at P < 0.05. The prognostic efficacy of the models was evaluated through the analysis of receiver operating characteristic (ROC) curves, with the area under the ROC curve (AUC) serving as a criterion for model selection. The decision curve analysis (DCA) and concordance index (C-index) were employed to assess the precision of the optimal model. RESULTS: Multivariate analysis revealed age, T stage, and metabolic tumor volume (MTV) for the primary nasopharyngeal tumor (MTVT) as significant independent prognostic factors for overall survival (OS) in NPC patients. Additionally, the LASSO model identified six key variables, including peak standardized uptake value (SUV-peak) for the primary nasopharyngeal tumor (SUV-peak(T)), MTVT, heterogeneity index for neck lymph nodes (HIN), age, pathological type, and T stage. Remarkably, the LASSO model demonstrated superior performance with a 5-year AUC of 0.849 compared to other models. Further assessment using the C-index and DCA confirmed the accuracy of the LASSO model. Subgroup analysis revealed notable risk factors, such as a high heterogeneity index (HI) for the primary nasopharyngeal tumor (HIT), MTV values for neck lymph nodes (MTVN), and HIN. CONCLUSIONS: We developed a novel prognostic machine learning model that integrates 18F-FDG PET-CT parameters and clinical characteristics, significantly enhancing prognosis prediction in NPC.

Omics-derived biological modules reflect metabolic brain changes in Alzheimer's disease.

INTRODUCTION: Brain glucose hypometabolism, indexed by the fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) imaging, is a metabolic signature of Alzheimer's disease (AD). However, the underlying biological pathways involved in these metabolic changes remain elusive. METHODS: Here, we integrated [18F]FDG-PET images with blood and hippocampal transcriptomic data from cognitively unimpaired (CU, n = 445) and cognitively impaired (CI, n = 749) individuals using modular dimension reduction techniques and voxel-wise linear regression analysis. RESULTS: Our results showed that multiple transcriptomic modules are associated with brain [18F]FDG-PET metabolism, with the top hits being a protein serine/threonine kinase activity gene cluster (peak-t(223) = 4.86, P value < 0.001) and zinc-finger-related regulatory units (peak-t(223) = 3.90, P value < 0.001). DISCUSSION: By integrating transcriptomics with PET imaging data, we identified that serine/threonine kinase activity-associated genes and zinc-finger-related regulatory units are highly associated with brain metabolic changes in AD. HIGHLIGHTS: We conducted an integrated analysis of system-based transcriptomics and fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) at the voxel level in Alzheimer's disease (AD). The biological process of serine/threonine kinase activity was the most associated with [18F]FDG-PET in the AD brain. Serine/threonine kinase activity alterations are associated with brain vulnerable regions in AD [18F]FDG-PET. Zinc-finger transcription factor targets were associated with AD brain [18F]FDG-PET metabolism.

Synthesis and preclinical evaluation of [18F]AlF-NODA-MP-C6-CTHRSSVVC as a PET tracer for CD163-positive tumor-infiltrating macrophages.

Positron emission tomography (PET) can provide information about tumor-associated macrophage (TAM) infiltration, as long as a suitable tracer is available. This study aimed to evaluate the radiolabeled peptide [18F]AlF-NODA-MP-C6-CTHRSSVVC as a potential PET tracer for imaging of the CD163 receptor, which is expressed on M2-type tumor-associated macrophages. The conjugated peptide NODA-MP-C6-CTHRSSVVC was labeled with aluminum [18F]fluoride. Tracer binding and its biodistribution were evaluated in an in vitro binding assay and in healthy BALB/c mice, respectively. In addition, different treatments with cyclophosphamide in tumor-bearing mice were used to assess whether the tracer could detect differences in CD163 expression caused by differential TAM infiltration. After 7 days of treatment, animals were injected with [18F]AlF-NODA-MP-C6-CTHRSSVVC, and a 60-min dynamic PET scan was performed, followed by an ex vivo biodistribution study. [18F]AlF-NODA-MP-C6-CTHRSSVVC was prepared in 23 ± 6 % radiochemical yield and showed approximately 50 % of specific receptor-mediated binding in an in vitro binding assay on human CD163-expressing tissue homogenates. No CD163-mediated binding of [18F]AlF-NODA-MP-C6-CTHRSSVVC was detected by PET under normal physiological conditions in healthy BALB/c mice. On the other hand, CD163-positive xenograft tumors were clearly visualized with PET and a positive correlation was found between CD163 levels and the [18F]AlF-NODA-MP-C6-CTHRSSVVC tumor-to-muscle ratio (TMR) obtained from the PET images (Pearson r = 0.76, p = 0.002). No significant differences in the CD163 protein level and in the tracer uptake between treatment groups were found in the tumors. Taken together, [18F]AlF-NODA-MP-C6-CTHRSSVVC appears a promising candidate PET tracer for M2-type TAM, as it binds specifically to CD163 in vitro and its tumor uptake correlates well with CD163 expression in vivo.

Warfarin use is associated with higher aortic bioprosthetic 18F-fluoride PET uptake.

BACKGROUND: Prevalence of bioprosthetic valve degeneration (BVD) is rising as the use of bioprosthetic aortic valves increases. Detecting early signs of BVD remains a challenge, with conventional imaging methods often failing to identify early deterioration stages. 18F-fuoride positron emission tomography (PET-CT) is an emerging technique that offers promising prospects to detect subclinical BVD. This study aimed to compare early PET parameters of fluoride uptake with echocardiographic hemodynamic parameters and compare outcomes according to anticoagulation in patients who received bioprosthetic valves. METHODS: This is a sub-study of the ANTIPRO clinical trial, which involved patients undergoing surgical aortic valve replacement (SAVR) with a porcine bioprosthesis and randomized them into anticoagulated and non-anticoagulated groups. Hemodynamic changes were assessed by transthoracic echocardiography (TTE), while 18F-fluoride PET-CT quantified fluoride uptake and divided the patients in two groups: high-uptake and low-uptake. Mean and maximum gradients by TTE at three years were compared between the two uptake groups. Fluoride uptake was also compared between the anticoagulated and control groups. RESULTS: We found no significant differences in transprosthetic gradients between high-uptake(21.4 ± 8.6 mmHg) and low-uptake(17.3 ± 11.2 mmHg.p = 0.244) PET-defined groups in this specific timeframe. Notably, anticoagulated patients exhibited significantly risk of higher fluoride uptake(OR = 4.34;95%CI:1.04-18.21.p = 0.045). CONCLUSIONS: No association was found between fluoride uptake and hemodynamic evaluation. Anticoagulation was associated with higher fluoride uptake. These findings highlight the emerging role of PET-CT in studying bioprosthetic aortic valves and emphasize the need for extended follow-up to evaluate the impact of anticoagulation on valve degeneration.

Inguinal lymph node metastases from prostate cancer: clinical, pathology, and multimodality imaging considerations.

Objective: To investigate clinical, pathology, and imaging findings associated with inguinal lymph node (LN) metastases in patients with prostate cancer (PCa). Materials and Methods: This was a retrospective single-center study of patients with PCa who underwent imaging and inguinal LN biopsy between 2000 and 2023. We assessed the following aspects on multimodality imaging: inguinal LN morphology; extrainguinal lymphadenopathy; the extent of primary and recurrent tumors; and non-nodal metastases. Imaging, clinical, and pathology features were compared between patients with and without metastatic inguinal LNs. Results: We evaluated 79 patients, of whom 38 (48.1%) had pathology-proven inguinal LN metastasis. Certain imaging aspects- short-axis diameter, prostate-specific membrane antigen uptake on positron-emission tomography, membranous urethra involvement by the tumor, extra-inguinal lymphadenopathy, and distant metastases-were associated with pathology-proven inguinal LN metastases (p < 0.01 for all). Associations with long-axis diameter, fatty hilum, laterality, and uptake of other tracers on positronemission tomography were not significant (p = 0.09-1.00). The patients with metastatic inguinal LNs had higher prostate-specific antigen levels and more commonly had castration-resistant PCa (p < 0.01), whereas age, histological grade, and treatment type were not significant factors (p = 0.07-0.37). None of the patients had inguinal LN metastasis in the absence of locally advanced disease with membranous urethra involvement or distant metastasis. Conclusion: Several imaging, clinical, and pathology features are associated with inguinal LN metastases in patients with PCa. Isolated metastasis to inguinal LNs is extremely rare and unlikely to occur in the absence of high-risk imaging, clinical, or pathology features.

Objetivo: Investigar achados clinicopatológicos e de imagem associados a metástases linfonodais inguinais em pacientes com câncer de próstata (CaP). Materiais e Métodos: Estudo retrospectivo de uma única instituição de pacientes com CaP submetidos a exames de imagem e biópsia inguinal de linfonodos em 2000­2023. A imagem multimodalidade foi avaliada para morfologia inguinal do linfonodo, linfadenopatia fora da região inguinal, extensão do CaP primário/recorrente e sítios metastáticos não nodais. Características de imagem e clinicopatológicas foram comparadas entre pacientes com e sem linfonodos inguinais metastáticos pela patologia. Resultados: Entre 79 pacientes estudados, 38 (48,1%) apresentaram metástase inguinal de linfonodo comprovada patologicamente. Certos achados de imagem ­ diâmetro do eixo curto, captação do antígeno de membrana prostático específico na tomografia por emissão de pósitrons, envolvimento da uretra membranosa pelo tumor, linfadenopatia fora da região inguinal e metástases a distância ­ foram associados com metástases inguinais no linfonodo pela patologia (p < 0,01). Diâmetro de eixo longo, hilo gorduroso, lateralidade, captação em outros traçadores de tomografia por emissão de pósitrons não foram significativos (p = 0,09­1,00). Clinicopatologicamente, os pacientes com linfonodos inguinais metastáticos apresentaram maior antígeno prostático específico e foram mais resistentes à castração (p < 0,01); idade, grau histológico e tipo de tratamento não foram estatisticamente significantes (p = 0,07­0,37). Nenhum paciente apresentou metástase inguinal isolada no linfonodo na ausência de doença localmente avançada com envolvimento da uretra membranosa ou metástase a distância. Conclusão: Várias características de imagem e clinicopatológicas foram associadas a metástases em LNs inguinais em pacientes com CaP. A metástase isolada para os LNs inguinais é extremamente rara e é improvável que ocorra na ausência de características de imagem e clinicopatológicas de alto risco.

Mimicry of Rhabdomyosarcoma by Tonsillar Actinomycosis: Case Report.

Actinomycosis is a rare infectious disease characterized by slowly progressive, chronic suppurative lesions, often mistaken for malignancies due to its ability to mimic them. It is caused by Actinomyces bacteria, which are part of the normal flora of the human oropharynx, gastrointestinal, and urogenital tracts. This case report describes a 51-year-old male with a history of mandibular rhabdomyosarcoma presenting with severe shoulder and hip pain, dysphagia, and headaches, initially suspected to be a cancer recurrence. However, after further investigation, including a PET-CT and tonsillectomy, the diagnosis of actinomycosis was confirmed through histopathological examination. The case highlights the diagnostic challenges of actinomycosis, especially in patients with complex clinical histories, emphasizing the importance of considering it as a differential diagnosis in similar presentations. The patient was treated with long-term antibiotic therapy, predominantly beta-lactams, demonstrating the necessity of a comprehensive diagnostic approach and the implications of a delayed diagnosis. This case underscores the critical need for high clinical suspicion and awareness among healthcare professionals regarding the potential for actinomycosis to mimic more common diseases, ensuring timely and accurate treatment.

PET myocardial perfusion imaging: Trends, challenges, and opportunities.

Various non-invasive images are used in clinical practice for the diagnosis and prognostication of chronic coronary syndromes. Notably, quantitative myocardial perfusion imaging (MPI) through positron emission tomography (PET) has seen significant technical advancements and a substantial increase in its use over the past two decades. This progress has generated an unprecedented wealth of clinical information, which, when properly applied, can diagnose and fine-tune the management of patients with different types of ischemic syndromes. This state-of-art review focuses on quantitative PET MPI, its integration into clinical practice, and how it holds up at the eyes of modern cardiac imaging and revascularization clinical trials, along with future perspectives.

[Retroperitoneal schwannoma mimicking colorectal cancer metastases: a false positive result report.] / Schwannoma retroperitoneal simulando metástasis de cáncer colorrectal: reporte de un resultado falso positivo.

Introduction: schwannomas are benign and common soft tissue tumors. They are usually asymptomatic and are discovered for other reasons. Materials: we present the case of an 82-year-old male patient with a recent diagnosis of moderately differentiated adenocarcinoma of the colon and a hypermetabolic periaortic nodule as an incidental finding. Results: percutaneous biopsy of the periaortic nodule confirmed the diagnosis of schwannoma. At one year of follow-up, growth of the schwannoma has been demonstrated. There are no signs of progression of his oncological disease. Conclusions: schwannomas are benign tumors, rarely found in the retroperitoneum and can be sources of false-positive positron emission tomography results.

Introducción: los schwannomas son tumores benignos y frecuentes de las partes blandas. Habitualmente son asintomáticos y son descubiertos por otros motivos. Materiales y métodos: presentamos el caso de un paciente masculino de 82 años con diagnóstico reciente de adenocarcinoma de colon moderadamente diferenciado y con un nódulo periaórtico hipermetabólico como hallazgo incidental. Resultados: la biopsia percutánea del nódulo periaórtico confirmó el diagnóstico de schwannoma. Al año de seguimiento, se ha demostrado crecimiento del schwannoma. No hay signos de progresión de su enfermedad oncológica. Conclusión: los schwannomas son tumores benignos, infrecuentes en el retroperitoneo y pueden ser fuentes de resultados falsos positivos en tomografía por emisión de positrones.

Phenotypic and Positron Emission Tomography with [18F]fluordeoxyglucose (FDG PET) differences in corticobasal syndrome: comparison of two cases.

Corticobasal syndrome (CBS) is a rare cause of dementia and comprises varied combinations of subcortical signs (akinetic-rigid parkinsonism, dystonia, or myoclonus) with cortical signs (apraxia, alien hand or cortical sensory deficit), usually asymmetric. We aimed to report and compare the clinical and neuroimaging presentation of two patients diagnosed with CBS. While case 1 had severe non-fluent aphasia associated with mild apraxia and limb rigidity, case 2 had a more posterior cognitive impairment, with a different language pattern associated with marked visuospatial errors and hemineglect. FDG PET played a significant role in diagnosis, suggesting, in the first case, corticobasal degeneration and, in the second, Alzheimer's disease pattern. CBS has been widely studied with the advent of new in vivo methods such as brain FDG PET. Studies that deepen the phenotypic and biomarker heterogeneity of CBS will be of great importance for better classification, prognosis, and treatment of the condition.

A síndrome corticobasal (SCB) é uma causa rara de demência e compreende combinações variadas de sinais subcorticais (parkinsonismo acinético-rígido, distonia ou mioclonias) com sinais corticais (apraxia, mão alienígena ou déficit sensorial cortical), geralmente assimétricos. Nosso objetivo foi relatar e comparar as apresentações clínica e de neuroimagem de dois pacientes com diagnóstico de SCB. Enquanto o caso 1 apresentava afasia grave não fluente associada a apraxia leve e rigidez de membros, o caso 2 exibia comprometimento cognitivo mais posterior, com padrão de linguagem distinto, erros visuoespaciais e heminegligência. O FDG PET teve papel significativo no diagnóstico, sugerindo, no primeiro caso, degeneração corticobasal e, no segundo, padrão Alzheimer. A SCB tem sido amplamente estudada com o advento de novos métodos in vivo, como o FDG PET cerebral. Estudos que aprofundem a heterogeneidade fenotípica e de biomarcadores da SCB serão de grande importância para melhor classificação, prognóstico e tratamento da doença.

Linfoma anaplásico de grandes células T associado ao uso de implantes (BIA-ALCL): relato de caso / Implant-associated anaplastic large T-cell lymphoma (BIA-ALCL): case report

Reconhecido pela Organização Mundial de Saúde em 2016, o linfoma anaplásico de grandes células associado ao implante mamário (BIA-ALCL) é um subtipo incomum de linfoma não Hodgkin de células T, que se desenvolve após a inserção de próteses mamárias. A doença é uma afecção rara que afeta cerca de uma a cada 30.000 pessoas com implante mamário texturizado. As principais manifestações clínicas são o seroma tardio, assimetria mamária, massa e contratura capsular, com frequência mais elevada do primeiro. O explante da prótese com capsulectomia total pode ser suficiente para tratar o ALCL, com ressecções estendidas a locais adjacentes, quando necessário. Entretanto, em alguns casos, é realizada a radioterapia e/ou quimioterapia adjuvante. Conclui-se que, para um diagnóstico precoce e um tratamento efetivo, mulheres com seroma de aparecimento súbito e tardio deverão realizar exames complementares para a exclusão dessa afecção, mesmo com tempo inferior à média de desenvolvimento, que é de cerca de 10,6 anos.

Recognized by the World Health Organization in 2016, breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is an uncommon subtype of T-cell non-Hodgkin lymphoma that develops after the insertion of breast implants. The disease is a rare condition that affects approximately one in every 30,000 people with textured breast implants. The main clinical manifestations are late seroma, breast asymmetry, mass, and capsular contracture, with a higher frequency of the former. Explantation of the prosthesis with total capsulectomy may be sufficient to treat ALCL, with resections extended to adjacent sites when necessary. However, in some cases, adjuvant radiotherapy and/or chemotherapy is performed. It is concluded that, for an early diagnosis and effective treatment, women with sudden and late-onset seroma should undergo additional tests to exclude this condition, even with a shorter development time than the average, which is around 10.6 years.

Splenic Embolism in Infective Endocarditis: A Systematic Review of the Literature with an Emphasis on Radiological and Histopathological Diagnoses.

Infective endocarditis (IE) is characterised by fever, heart murmurs, and emboli. Splenic emboli are frequent in left-sided IE. A systematic review of the literature published on splenic embolism (SE) between 2000 and 2023 was conducted. Search strategies in electronic databases identified 2751 studies published between 1 January 2000 and 4 October 2023, of which 29 were finally included. The results showed that the imaging tests predominantly used to detect embolisms were computed tomography (CT), magnetic resonance imaging, positron emission tomography (PET)/CT, single-photon emission computed tomography/CT, ultrasound, and contrast-enhanced ultrasound. More recent studies typically used 18F-FDG PET-CT. The proportion of SE ranged from 1.4% to 71.7%. Only seven studies performed systematic conventional CT screening for intra-abdominal emboli, and the weighted mean frequency of SE was 22% (range: 8-34.8%). 18F-FDG PET-CT was performed systematically in seven studies, and splenic uptake was found in a weighted mean of 4.5%. There was a lack of uniformity in the published literature regarding the frequency and management of splenic embolisation. CT scans were the most frequently used method, until recently, when 18F-FDG PET-CT scans began to predominate. More data are necessary regarding the frequency of SE, especially focusing on their impact on IE management and prognosis.

Evidence of brain metabolism redistribution from neocortex to primitive brain structures in early acute COVID-19 respiratory syndrome.

BACKGROUND: Neuropsychiatric sequelae of COVID-19 have been widely documented in patients with severe neurological symptoms during the chronic or subacute phase of the disease. However, it remains unclear whether subclinical changes in brain metabolism can occur early in the acute phase of the disease. The aim of this study was to identify and quantify changes in brain metabolism in patients hospitalized for acute respiratory syndrome due to COVID-19 with no or mild neurological symptoms. RESULTS: Twenty-three non-intubated patients (13 women; mean age 55.5 ± 12.1 years) hospitalized with positive nasopharyngeal swab test (RT-PCR) for COVID-19, requiring supplemental oxygen and no or mild neurological symptoms were studied. Serum C-reactive protein measured at admission ranged from 6.43 to 189.0 mg/L (mean: 96.9 ± 54.2 mg/L). The mean supplemental oxygen demand was 2.9 ± 1.4 L/min. [18F]FDG PET/CT images were acquired with a median of 12 (4-20) days of symptoms. After visual interpretation of the images, semiquantitative analysis of [18F]FDG uptake in multiple brain regions was evaluated using dedicated software and the standard deviation (SD) of brain uptake in each region was automatically calculated in comparison with reference values of a normal database. Evolutionarily ancient structures showed positive SD mean values of [18F]FDG uptake. Lenticular nuclei were bilaterally hypermetabolic (> 2 SD) in 21/23 (91.3%) patients, and thalamus in 16/23 (69.6%), bilaterally in 11/23 (47.8%). About half of patients showed hypermetabolism in brainstems, 40% in hippocampi, and 30% in cerebellums. In contrast, neocortical regions (frontal, parietal, temporal and occipital lobes) presented negative SD mean values of [18F]FDG uptake and hypometabolism (< 2 SD) was observed in up to a third of patients. Associations were found between hypoxia, inflammation, coagulation markers, and [18F]FDG uptake in various brain structures. CONCLUSIONS: Brain metabolism is clearly affected during the acute phase of COVID-19 respiratory syndrome in neurologically asymptomatic or oligosymptomatic patients. The most frequent finding is marked hypermetabolism in evolutionary ancient structures such as lenticular nucleus and thalami. Neocortical metabolism was reduced in up to one third of patients, suggesting a redistribution of brain metabolism from the neocortex to evolutionary ancient brain structures in these patients.

Utility of multimodal molecular imaging in the diagnosis and decision-making in arterial diseases.

Arterial diseases are prevalent in the general population, particularly in the elderly, and they are among the main causes of morbidity and mortality worldwide. Nuclear imaging is a useful tool in diagnosis and follow-up in different areas of medicine, and over the last 2 decades, these study modalities have become more relevant in the field of angiology and vascular surgery due to their potential benefit in the interpretation of pathophysiological mechanisms associated with the natural history and severity of diseases that affect the circulation such as vasculitis, degenerative aortic aneurysms (AA), peripheral arterial disease (PAD), and complications following reconstructive procedures such as graft infections. The literature has shown evidence of an important number of radiotracers for specific molecules involved in the activity of these entities and their utility as predictors during surveillance and possible therapeutic targets. The present narrative review aims to describe the use of nuclear medicine, imaging methods, and radiotracers that have been applied in arterial diseases, as well as the advantages and considerations, their importance in the diagnosis and follow-up of these complex groups of patients, and future perspectives.

Impact of 18F-FDG PET/CT in the management decisions of breast cancer board on early-stage breast cancer.

PURPOSE: Breast cancer is the most common malignancy accounting for 11.7% of all cancer cases, with a rising incidence rate. Various diagnostic methods, including 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT), play a crucial role in breast cancer diagnosis and staging. However, the unnecessary use of advanced imaging techniques such as PET/CT in early-stage breast cancer can have negative effects on both economics and patients. We aimed to investigate the impact of PET/CT on the management decisions of early-stage breast cancer patients by the breast cancer tumor board. METHODS: A retrospective analysis was performed on a cohort of 81 patients with early-stage breast cancer who were evaluated by breast cancer tumor board from January 2015 to December 2020. Demographic, clinical, and radiographic data, along with surgical procedures and treatment options, were documented and analyzed. RESULTS: The results showed that 18F-FDG PET/CT had a moderate impact on treatment decisions of breast cancer tumor board, as only treatment decisions were changed in 14,86% of the patients. The surgical procedure decision of breast cancer tumor board changed in 12.35% of patients, while 87.65% of patients had consistent decisions before and after PET/CT. Pathological assessments revealed invasive ductal carcinoma as the most prevalent tumor type, and molecular subtypes were predominantly luminal B. PET/CT use had limited impact on surgical procedures and did not significantly alter treatment decisions of breast cancer tumor board in this early-stage breast cancer cohort. CONCLUSIONS: In conclusion, this study highlights the importance of adherence to the guidelines and appropriate use of PET/CT in early-stage breast cancer management. PET/CT should be reserved for cases where it is clinically warranted, considering the potential economic burden and minimal impact on treatment decisions of breast cancer tumor board in this patient population.

Impact of baseline and interim quantitative PET parameters on outcomes of classical Hodgkin Lymphoma.

Currently, analysis of interim PET (iPET) according to the Deauville score (DS) is the most important predictive factor in Hodgkin lymphoma (HL); however, there is room for improvement in its prognostic power. This study aimed to evaluate the prognostic value of quantitative PET analysis (maximum standard uptake value [SUVmax], total metabolic tumor volume [TMTV] and total lesion glicolysis [TLG]) at baseline (PET0) and iPET in a retrospective cohort of newly diagnosed classical HL. For positive iPET (+ iPET), the reduction of quantitative parameters in relation to PET0 (ΔSUVmax, ΔTMTV and ΔTLG) was calculated. Between 2011 and 2017, 234 patients treated with ABVD were analyzed. Median age was 30 years-old, 59% had advanced stage disease, 57% a bulky mass and 25% a + iPET (DS 4-5). At baseline, high TLG was associated with an increased cumulative incidence of failure (CIF) (p = 0.032) while neither SUVmax, TMTV or TLG were associated with overall survival (OS) or progression-free survival (PFS). In multivariate analysis, only iPET was associated with CIF (p < 0.001). Among ΔSUVmax, ΔTMTV and ΔTLG, only a ΔSUVmax ≥ 68.8 was significant for PFS (HR: 0.31, CI95%: 0.11-0.86, p = 0.024). A subset of patients with improved PFS amongst + iPET was identified by the quantitative (ΔSUVmax ≥ 68.8%) analysis. In this real-world Brazilian cohort, with prevalent high-risk patients, quantitative analysis of PET0 did not demonstrate to be prognostic, while a dynamic approach incorporating the ΔSUVmax to + iPET succeeded in refining a subset with better prognosis. These findings warrant validation in larger series and indicate that not all patients with + iPET might need treatment intensification.

Initial evaluation and external validation of 68Ga-PSMA-11 PET/CT in tubarial gland characterization.

INTRODUCTION: Radiotracer 68Ga-PSMA-11 used in PET/CT scans allows for identification and localization of gland tissue. It allows for their consideration in clinical scenarios and to design further and stronger research to answer pertinent questions regarding their function and implications. We aimed to externally validate first reported findings of location, size, and ligand uptake of the tubarial glands using 68Ga-PSMA-11 PET/CT. MATERIALS AND METHODS: A cross-sectional study was performed with 68Ga-PSMA-11 PET/CT studies of patients with prostate cancer confirmed diagnosis from the database of the Radiology Department from 2018 to 2022. The maximum cephalocaudal length (CCL) in the tubarial glands and the Maximum Standardized Uptake Value (SUVmax) of major glands were recorded. RESULTS: A total of 202 patients were included (mean age 67.43 ± 8.5). The mean CCL of the tubarial glands was 37.38 ± 9.84 and a SUVmax of 6.56 ± 2.14. The rest of the glands were as follows: parotid 15.12 ± 4.43, submandibular 16.82 ± 5.43 and sublingual 5.84 ± 3.24. No differences were found between laterality. A weak correlation between age and SUVmax of tubarial glands was identified. Tubarial glands had a similar 68Ga-PSMA-11 uptake to that of sublingual glands. CONCLUSION: This study corroborates the existence of a conglomerate of glands in the nasopharynx roof, near the posterolateral pharyngeal recess. It serves as validation in a different population with similar results in previous research. Without 68GA-PSMA-11 PET/CT the abundance, configuration and potential clinical relevance of these glands would probably not have been identified. Radiotracer uptake was similar amongst the major salivary glands, with a more similar uptake to that shown by the sublingual gland.

Probable 4-Repeat Tauopathy Criteria Predict Brain Amyloid Negativity, Distinct Clinical Features, and FDG-PET/MRI Neurodegeneneration Patterns in Corticobasal Syndrome.

BACKGROUND: Corticobasal syndrome (CBS) is associated with diverse underlying pathologies, including the four-repeat (4R)-tauopathies. The Movement Disorders Society (MDS) criteria for progressive supranuclear palsy (PSP) proposed the novel category "probable 4R-tauopathy" to address the phenotypic overlap between PSP and corticobasal degeneration (CBD). OBJECTIVES: To investigate the clinical ability of the MDS-PSP criteria for probable 4R-tauopathy in predicting a negative amyloid-PET in CBS. Additionally, this study aims to explore CBS patients classified as 4R-tauopathy concerning their clinical features and neuroimaging degeneration patterns. METHODS: Thirty-two patients with probable CBS were prospectively evaluated and split into those who fulfilled or did not fulfill the 4R-tauopathy criteria (CBS-4RT+ vs. CBS-4RT-). All patients underwent positron emission tomographies (PET) with [18 F]fluorodeoxyglucose and [11 C]Pittsburgh Compound-B (PIB) on a hybrid PET-MRI scanner to perform multimodal quantitative comparisons with a control group. RESULTS: Eleven patients were clinically classified as CBS-4RT+, and only one had a positive PIB-PET. The CBS-4RT+ classification had 92% specificity, 52% sensitivity, and 69% accuracy in predicting a negative PIB-PET. The CBS-4RT+ group presented with dysarthria and perseveration more often than the CBS-4RT- group. Moreover, the CBS-4RT+ group showed a prominent frontal hypometabolism extending to the supplementary motor area and striatum, and brain atrophy at the anterior cingulate and bilateral striata. CONCLUSIONS: The 4R-tauopathy criteria were highly specific in predicting a negative amyloid-PET in CBS. Patients classified as 4R-tauopathy presented distinct clinical aspects, as well as brain metabolism and atrophy patterns previously associated with tauopathies.

PSMA PET/CT in the Brazilian Unified Healthcare System reduces costs with futile salvage therapies in the management of cases of biochemical recurrence of prostate cancer / PET/CT-PSMA no Sistema Único de Saúde reduz custos com terapias de resgate fúteis no manejo de pacientes com recidiva bioquímica de câncer de próstata

Abstract Objective: To compare costs between treatment strategies employed prior to and after prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) via the Brazilian Unified Health Care System and their impact on the therapeutic management of biochemical recurrence of prostate cancer. Materials and Methods: The referring physicians were surveyed on their treatment intentions (strategies) at two different time points: prior to and after PSMA PET/CT. Cost comparison results are presented as median (IQR) for each of the two strategies. The shift in therapeutic management after PSMA PET/CT was also analyzed. Results: The study sample included 59 patients (mean age: 65.9 years). The PSMA PET/CT result was considered positive in 38 patients (64.4%) and was found to have an impact on the treatment strategy in for 36 patients (61.0%). Prior to PSMA PET/CT, salvage therapy (i.e., treatment with curative intent) was the intended treatment for most patients, and that was significantly less so after the examination (76.3% vs. 45.8%; p < 0.001). Conversely, a strategy involving systemic (i.e., palliative) therapy became more common after PSMA PET/CT (23.7% vs. 54.2%; p < 0.001). The after-PSMA PET/CT strategy presented higher overall costs than did the before-PSMA PET/CT strategy, in all scenarios evaluated. In all scenarios, nearly half of this cost difference was related to the cost of the PSMA PET/CT itself, the remainder being related to the new treatment choices that stemmed from knowledge of the PSMA PET/CT findings. Conclusion: For patients treated within the Brazilian Unified Health Care System, PSMA PET/CT presented higher costs in comparison with conventional imaging methods. Adding PSMA PET/CT to the workflow had an impact on therapeutic management, mainly representing a shift from futile curative treatments to systemic palliative ones. The amount of funds that could potentially be saved by not providing such futile treatments would suffice to evaluate roughly two patients with PSMA PET/CT scans for each futile treatment strategy avoided.

Resumo Objetivo: Comparar custos entre estratégias antes e após o exame de PET/CT-PSMA da perspectiva do Sistema Único de Saúde e seu impacto no manejo terapêutico para pacientes com recidiva bioquímica de câncer de próstata. Materiais e Métodos: Os médicos solicitantes informaram a intenção terapêutica em dois momentos: antes e após o exame. Os resultados de comparação de custo estão apresentados como medianas de custo (p25; p75). A mudança na intenção terapêutica também foi analisada. Resultados: O estudo envolveu 59 pacientes (idade média: 65,9 anos). A PET/CT-PSMA foi considerada positiva em 38 dos 59 pacientes (64.4%). O exame impactou a estratégia de tratamento para 36 pacientes (61%). Antes da obtenção das informações da PET/CT-PSMA, a terapia de resgate (i.e., com intenção curativa) era o tratamento sugerido para a maioria dos pacientes, e após o exame, reduziu significativamente (76,3% vs 45,8%; p < 0,001). Em contrapartida, a terapia sistêmica (i.e., paliativa) aumentou como intenção de tratamento após o exame (23,7% vs 54,2%; p < 0,001). A estratégia "após PET/CT-PSMA" apresentou maiores custos em relação à estratégia "antes da PET/CT-PSMA" nos cenários comparados. Cerca de metade da diferença de custos entre as duas estratégias foi relacionada aos custos do exame propriamente ditos, enquanto a outra metade foi relacionada às novas escolhas de tratamento a partir do exame. Conclusão: Oferecer a PET/CT-PSMA no Sistema Único de Saúde apresentou maiores custos em relação à estratégia com métodos de imagem convencionais e impactou o manejo terapêutico, pelo favorecimento de tratamentos sistêmicos paliativos no lugar de tratamentos curativos fúteis. A quantidade de recursos que poderiam ser poupados ao evitar tratamentos fúteis seria suficiente para avaliar aproximadamente dois pacientes com exames de PET/CT-PSMA para cada estratégia de tratamento fútil evitada.