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.

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.

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.

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.

Evolução da Captação Miocárdica de 18F-FDG em Paciente com Diagnóstico de Cardiotoxicidade / Progression of Myocardial 18F-FDG Uptake in a Patient with Cardiotoxicity

Resumo O objetivo deste relato é mostrar a evolução da cardiotoxicidade (CTX) por quimioterápicos em paciente com linfoma por exames de imagens, destacando a importância da captação miocárdica de flúor-18 fluordeoxiglicose (18F-FDG) pela tomografia por emissão de pósitrons, acoplada à tomografia computadorizada (PET/CT). Feminino, 43 anos, com linfoma uterino, submetida a histerectomia, três esquemas de quimioterapia (QT), sucessivamente, e radioterapia. Apresentou episódios de insuficiência cardíaca aguda dois anos após QT. Ecocardiograma mostrou redução da fração de ejeção do ventrículo esquerdo (FEVE). Análise retrospectiva do 18F-FDG PET/CT observou elevação da captação miocárdica em todos os exames durante o seguimento oncológico. Apesar da remissão oncológica, a paciente desenvolveu IC com FEVE reduzida. Durante a QT, ocorreu aumento difuso e significativo da captação miocárdica de 18F-FDG, que precedeu a queda do desempenho cardíaco, e pareceu refletir alterações metabólicas nos cardiomiócitos relacionadas à CTX. A análise da captação miocárdica de 18F-FDG modificaria o desfecho cardiológico da paciente? Esse questionamento é relevante, visto que outros pacientes podem se beneficiar desse método como marcador precoce de CTX. Os exames de imagem são imprescindíveis no acompanhamento de pacientes com risco de CTX. O ecocardiograma permanece como principal auxílio diagnóstico, porém o 18F-FDG PET/CT pode estar surgindo como uma poderosa ferramenta para um diagnóstico mais precoce dessa condição clínica.

Abstract The objective of this case report was to present the progression of chemotherapy-induced cardiotoxicity in a patient with lymphoma, highlighting the importance of myocardial fluor-18-fluorodeoxyglucose (18F-FDG) uptake by positron emission tomography coupled with computed tomography (PET/CT). 43-year-old female patient with uterine lymphoma, who underwent hysterectomy followed by three chemotherapy regimens and radiotherapy. The patient had episodes of acute heart failure two years after chemotherapy. Echocardiogram revealed a reduction in left ventricular ejection fraction (LVEF). A retrospective analysis of 18F-FDG PET/CT showed an increase in myocardial uptake in all tests performed during oncologic treatment. Despite disease remission, the patient developed heart failure with reduced LVEF. During chemotherapy, there was a diffuse, significant increase in myocardial 18F-FDG uptake, which preceded the decrease in myocardial performance and seemed to reflect metabolic changes in cardiomyocytes, related to cardiotoxicity. Would an analysis of myocardial 18F-FDG uptake yield a different cardiac outcome in this patient? This question is relevant, considering that other patients may benefit from the use of PET as an early marker of cardiotoxicity. Imaging tests are essential in the follow-up of patients at risk of cardiotoxicity. Although echocardiography remains the main imaging test in the diagnosis of cardiotoxicity, 18F-FDG PET/CT may be a powerful tool for the early diagnosis of this condition.

Inguinal lymph node metastases from prostate cancer: clinical, pathology, and multimodality imaging considerations / Metástases de linfonodos inguinais de câncer de próstata: considerações clínicas, patológicas e de imagem multimodalidade

Abstract 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.

Resumo 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 2000-2023. 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 = 0,09-1,00). 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 = 0,07-0,37). 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.

Musculoskeletal pitfalls in 68Ga-PSMA PET/CT.

Prostate-specific membrane antigen (PSMA) is a transmembrane protein expressed in normal prostate cells and overexpressed in prostate cancer. Consequently, it is an important tool in the evaluation of prostate cancer, including the staging of high-risk patients and the assessment of biochemical recurrence. Despite the "specific" designation, benign musculoskeletal conditions, such as fractures, osteodegenerative changes, and fibrous dysplasia, can also show PSMA uptake, which can lead to misinterpretation of the imaging findings. Therefore, radiologists must be aware of these potential pitfalls, understand their causes, and fully analyze their morphologic features on unfused computed tomography (CT) and magnetic resonance imaging scans to correctly interpret the examination. In this pictorial essay, we review the basic characteristics of the 68Ga-PSMA positron-emission tomography/CT (PET/CT) radiotracer, discuss potential causes of false-positive findings on 68Ga-PSMA PET/CT in the musculoskeletal system, and illustrate the corresponding imaging findings.

O antígeno de membrana próstata específico (PSMA) é uma proteína transmembrana que apresenta expressão em células prostáticas normais e superexpressão em neoplasia da próstata. Dessa forma, é uma importante ferramenta na avaliação da neoplasia prostática, de utilidade no estadiamento de pacientes de alto risco e na análise de recorrência bioquímica. Apesar do termo "específico", condições musculoesqueléticas benignas podem demonstrar captação de PSMA, como fraturas, alterações osteodegenerativas e displasia fibrosa, podendo levar a uma avaliação equivocada dos achados de imagem. Assim, o radiologista deve conhecer esses potenciais pitfalls, compreender suas causas e analisar as características morfológicas nas imagens não fundidas de TC e RM para interpretar corretamente o exame. Neste ensaio iconográfico, revisaremos as características básicas do radiofármaco 68Ga-PSMA PET/CT, discutiremos possíveis causas de resultados falso-positivos na 68Ga-PSMA PET/CT no sistema musculoesquelético e ilustraremos os achados de imagem correspondentes.

Preoperative evaluation of prostate cancer by 68Ga-PMSA positron emission tomography/computed tomography: comparison with magnetic resonance imaging and with histopathological findings.

Objective: To evaluate the accuracy of preoperative positron emission tomography/computed tomography with 68Ga-labeled prostate-specific membrane antigen (68Ga-PSMA PET/CT) for staging prostate cancer and compare it with magnetic resonance imaging (MRI) using histopathology of surgical specimens as the gold standard. Materials and Methods: In this retrospective study, 65 patients with prostate cancer were analyzed. Results: The accuracy of 68Ga-PSMA PET/CT for tumor detection was 95%, and that of MRI was 91%. There was no difference between 68Ga-PSMA PET/CT and MRI regarding localization of the lesion. The sensitivity of 68Ga-PSMA PET/CT for detecting extraprostatic extension was quite low (14%). For detection of seminal vesicle invasion, 68Ga-PSMA PET/CT showed a sensitivity of 57% and accuracy of 91%. There was a moderate correlation between the maximum standardized uptake value (SUVmax) and the serum level of prostate-specific antigen (p < 0.01; ρ = 0.368) and between the SUVmax and the International Society of Urological Pathology (ISUP) grade (p < 0.01; ρ = 0.513). Conclusion: 68Ga-PSMA PET/CT is a promising tool for detecting and evaluating the primary tumor, which can alter the staging and management of the disease.

Objetivo: Avaliar a acurácia da tomografia por emissão de pósitrons/tomografia computadorizada com PSMA (PET-PMSA) pré-operatória para estadiamento do câncer de próstata e compará-la com a ressonância magnética (RM) utilizando o histopatológico cirúrgico como padrão ouro. Materiais e Métodos: Neste estudo retrospectivo foram analisados 65 pacientes com câncer de próstata. Resultados: A acurácia da PET-PSMA para a detecção tumoral foi de 95% e a da RM foi de 91%. Não houve diferença entre a PET-PSMA e a RM quanto à localização da lesão. A PET-PSMA apresentou baixa sensibilidade (14%) para detecção de extensão extraprostática em comparação ao histopatológico. Para detecção de invasão de vesícula seminal, a PET-PSMA apresentou sensibilidade de 57% e acurácia de 91% em comparação ao histopatológico. Houve correlação moderada entre o SUVmax e o PSA (p < 0,01; ρ = 0,368) e entre o SUVmax e o ISUP (p < 0,01; ρ = 0,513). Conclusão: A PET-PSMA é uma ferramenta promissora para detecção e avaliação do tumor primário, alterando o estadiamento e a conduta do paciente.

Head-to-head comparison of [68Ga]Ga-PSMA-11 and [18F]FDG PET/CT in multiple myeloma.

PURPOSE: The aim of this study was to compare [18F]FDG and [68Ga]Ga-PSMA-11 PET/CT image findings in patients with multiple myeloma (MM). METHODS: Twenty consecutive patients with symptomatic biopsy-proven MM were submitted to whole body [18F]FDG and [68Ga]Ga-PSMA-11 PET/CT with a time interval of 1-8 days between procedures. All lesions were counted and had their maximum SUV (SUVmax) measured. Intra-class correlation (ICC) was used to assess the agreement between [18F]FDG and [68Ga]Ga-PSMA-11 PET/CT findings. RESULTS: A total of 266 lesions were detected in 19/20 patients. [18F]FDG detected 223/266 (84%) lesions in 17 patients and [68Ga]Ga-PSMA-11 190/266 (71%) lesions in 19 patients. Both procedures did not identify any active lesion in 1 patient. Forty-three (16%) lesions were detected only by [68Ga]Ga-PSMA-11 and 76 (29%) only by [18F]FDG. Both tracers identified 147 (55%) lesions. Intralesional mismatch of FDG-PSMA uptake was identified in 25 of these 147 lesions, found in 8 different patients. Different lesions with uptake of only [18F]FDG or [68Ga]Ga-PSMA-11 in the same patient were found in 4 patients. The highest SUVmax of [18F]FDG and [68Ga]Ga-PSMA-11 had a median (min-max) SUVmax of 6.5 (2.0-37.8) and 5.5 (1.7-51.3), respectively. [18F]FDG and [68Ga]Ga-PSMA-11 respectively identified 18 and 19 soft tissue lesions. False-positive [18F]FDG findings had minimal or no uptake of [68Ga]Ga-PSMA-11. Good reliability (ICC ≥ 0.75) was found for number of lesions, number of soft tissue lesions and highest SUVmax in each patient. CONCLUSION: [18F]FDG or [68Ga]Ga-PSMA-11 alone can detect most MM lesions. Almost half of the lesions take up only one of the tracers, reflecting increased glycolysis or angiogenesis in specific lesions, and suggesting their possible complementary role in MM. The marked [68Ga]Ga-PSMA-11 uptake in some cases raises the possibility of a theranostic approach in selected patients.

Antimicrobial peptide for bacterial infection imaging: first case reported in Brazil

ABSTRACT Molecular imaging markers can be used to differentiate between infection and aseptic inflammation, determine the severity of infection, and monitor treatment responses. One of these markers is ubiquicidin(29-41) (UBI), a cationic peptide fragment that binds to the bacterial membrane wall and is labeled with gallium-68 (68Ga), a positron emitter radioisotope. The use of UBI in positron emission tomography (PET)/computed tomography (CT) for improved detection of lesions has been receiving considerable attention recently. Herein, we report the first case of 68Ga-UBI PET/CT performed in Brazil. The patient was a 39-year-old woman referred for a scan to confirm a clinical suspicion of chronic osteomyelitis of her fractured left tibia. PET images revealed radiotracer uptake near the posterior contour of the tibial fracture focus and the fixation plate, in the soft tissue around the distal half of the tibia, and in the non-consolidated fracture of the left distal fibula. Surgery for local cleaning was performed, and culture of a specimen collected from the surgical site confirmed the presence of Staphylococcus aureus. In the present case, 68Ga-UBI PET/CT, a non-invasive imaging modality, identified the infection foci in vivo, indicating its potential for clinical use.

Preoperative evaluation of prostate cancer by 68Ga-PMSA positron emission tomography/computed tomography: comparison with magnetic resonance imaging and with histopathological findings / Avaliação pré-operatória do câncer de próstata pela tomografia por emissão de pósitrons/tomografia computadorizada com PSMA-68Ga: comparação com ressonância magnética e com achados histopatológicos

Abstract Objective: To evaluate the accuracy of preoperative positron emission tomography/computed tomography with 68Ga-labeled prostate-specific membrane antigen (68Ga-PSMA PET/CT) for staging prostate cancer and compare it with magnetic resonance imaging (MRI) using histopathology of surgical specimens as the gold standard. Materials and Methods: In this retrospective study, 65 patients with prostate cancer were analyzed. Results: The accuracy of 68Ga-PSMA PET/CT for tumor detection was 95%, and that of MRI was 91%. There was no difference between 68Ga-PSMA PET/CT and MRI regarding localization of the lesion. The sensitivity of 68Ga-PSMA PET/CT for detecting extraprostatic extension was quite low (14%). For detection of seminal vesicle invasion, 68Ga-PSMA PET/CT showed a sensitivity of 57% and accuracy of 91%. There was a moderate correlation between the maximum standardized uptake value (SUVmax) and the serum level of prostate-specific antigen (p < 0.01; ρ = 0.368) and between the SUVmax and the International Society of Urological Pathology (ISUP) grade (p < 0.01; ρ = 0.513). Conclusion: 68Ga-PSMA PET/CT is a promising tool for detecting and evaluating the primary tumor, which can alter the staging and management of the disease.

Resumo Objetivo: Avaliar a acurácia da tomografia por emissão de pósitrons/tomografia computadorizada com PSMA (PET-PMSA) pré-operatória para estadiamento do câncer de próstata e compará-la com a ressonância magnética (RM) utilizando o histopatológico cirúrgico como padrão ouro. Materiais e Métodos: Neste estudo retrospectivo foram analisados 65 pacientes com câncer de próstata. Resultados: A acurácia da PET-PSMA para a detecção tumoral foi de 95% e a da RM foi de 91%. Não houve diferença entre a PET-PSMA e a RM quanto à localização da lesão. A PET-PSMA apresentou baixa sensibilidade (14%) para detecção de extensão extraprostática em comparação ao histopatológico. Para detecção de invasão de vesícula seminal, a PET-PSMA apresentou sensibilidade de 57% e acurácia de 91% em comparação ao histopatológico. Houve correlação moderada entre o SUVmax e o PSA (p < 0,01; ρ = 0,368) e entre o SUVmax e o ISUP (p < 0,01; ρ = 0,513). Conclusão: A PET-PSMA é uma ferramenta promissora para detecção e avaliação do tumor primário, alterando o estadiamento e a conduta do paciente.

Musculoskeletal pitfalls in 68Ga-PSMA PET/CT / Pitfalls do sistema musculoesquelético na PET/CT com 68Ga-PSMA

Abstract Prostate-specific membrane antigen (PSMA) is a transmembrane protein expressed in normal prostate cells and overexpressed in prostate cancer. Consequently, it is an important tool in the evaluation of prostate cancer, including the staging of high-risk patients and the assessment of biochemical recurrence. Despite the "specific" designation, benign musculoskeletal conditions, such as fractures, osteodegenerative changes, and fibrous dysplasia, can also show PSMA uptake, which can lead to misinterpretation of the imaging findings. Therefore, radiologists must be aware of these potential pitfalls, understand their causes, and fully analyze their morphologic features on unfused computed tomography (CT) and magnetic resonance imaging scans to correctly interpret the examination. In this pictorial essay, we review the basic characteristics of the 68Ga-PSMA positron-emission tomography/CT (PET/CT) radiotracer, discuss potential causes of false-positive findings on 68Ga-PSMA PET/CT in the musculoskeletal system, and illustrate the corresponding imaging findings.

Resumo O antígeno de membrana próstata específico (PSMA) é uma proteína transmembrana que apresenta expressão em células prostáticas normais e superexpressão em neoplasia da próstata. Dessa forma, é uma importante ferramenta na avaliação da neoplasia prostática, de utilidade no estadiamento de pacientes de alto risco e na análise de recorrência bioquímica. Apesar do termo "específico", condições musculoesqueléticas benignas podem demonstrar captação de PSMA, como fraturas, alterações osteodegenerativas e displasia fibrosa, podendo levar a uma avaliação equivocada dos achados de imagem. Assim, o radiologista deve conhecer esses potenciais pitfalls, compreender suas causas e analisar as características morfológicas nas imagens não fundidas de TC e RM para interpretar corretamente o exame. Neste ensaio iconográfico, revisaremos as características básicas do radiofármaco 68Ga-PSMA PET/CT, discutiremos possíveis causas de resultados falso-positivos na 68Ga-PSMA PET/CT no sistema musculoesquelético e ilustraremos os achados de imagem correspondentes.

[The intensity of PSMA intraprostatic uptake as a predictor of clinically significant prostate cancer]. / La intensidad de la captación intraprostática del PSMA como predictor de cáncer de próstata clínicamente significativo.

INTRODUCTION: Positron emission tomography (PET) with prostate-specific membrane antigen (PSMA) improves prostate cancer staging. Furthermore, the intensity of intraprostatic uptake of PSMA can predict clinically relevant oncologic outcomes. The objective of this study is to evaluate whether the intensity of PSMA uptake is associated with clinically significant prostate cancer and to determine which value of PSMA uptake best discriminates this relationship. METHODS: A cohort study of 40 patients with biopsy-proven prostate cancer prior to external radiotherapy was conducted. The correlation between intraprostatic PSMA uptake intensity and adverse pathological findings in prostate biopsy was evaluated. Which PSMA uptake value better discriminates clinically significant prostate cancer was assessed using ROC curves. RESULTS: Forty percent of the patients had a clinically significant prostate cancer and the maximum standardized uptake value (SUV max) had a mean of 11.5 (SD ± 7). The sample showed a Spearman correlation coefficient of 0.4 (p = 0.007). The area under the curve (AUC) was 0.73 and a SUV max = 9.5 showed a sensitivity of 0.81 and a specificity of 0.71 in the detection of clinically significant prostate cancer. CONCLUSION: Intraprostatic PSMA uptake intensity can be a new diagnostic tool in the detection of clinically significant prostate cancer. An uptake intensity equal or greater than 9.5 is correlated with clinically significant prostate cancer.

Introducción: La tomografía por emisión de positrones (PET) con antígeno de membrana específico de próstata (PSMA) mejora la estadificación del cáncer de próstata. Además, la intensidad de captación intraprostática del PSMA puede predecir resultados oncológicos clínicamente relevantes. Nuestro objetivo fue evaluar si la intensidad de captación de PSMA se asocia con el cáncer de próstata clínicamente significativo y poder conocer qué valor de captación de PSMA discrimina mejor esta relación. Métodos: Se realizó un estudio de cohorte de 40 pacientes con cáncer de próstata comprobado por biopsia previo a la realización de radioterapia externa. Se evaluó correlación entre intensidad de captación del PSMA intraprostático y los resultados patológicos adversos en la biopsia prostática. Se estudió qué valor de captación de PSMA discrimina mejor el cáncer de próstata clínicamente significativo utilizando curvas ROC. Resultados: El 40% de los pacientes tuvieron un cáncer de próstata clínicamente significativo, el maximum standardized uptake value (SUV max) tuvo una media de 11.5 (DE ± 7). La muestra arrojó un coeficiente de correlación Spearman de 0.4 (p = 0.007). El área bajo la curva (AUC) fue de 0.73, mostrando el punto de corte un SUV max = 9.5, sensibilidad 0.81 y especificidad 0.71 en la detección de cáncer de próstata clínicamente significativo. Conclusión: la intensidad de captación del PSMA intraprostático puede ser una nueva herramienta diagnóstica en la detección del cáncer de próstata clínicamente significativo. Una intensidad de captación = 9.5 tuvo una buena correlación con el cáncer de próstata clínicamente significativo.

La intensidad de la captación intraprostática del PSMA como predictor de cáncer de próstata clínicamente significativo / The intensity of PSMA intraprostatic uptake as a predictor of clinically significant prostate cancer

Resumen Introducción: La tomografía por emisión de positrones (PET) con antígeno de membrana específico de próstata (PSMA) mejora la estadificación del cáncer de próstata. Además, la intensidad de captación intraprostática del PSMA puede predecir resultados oncológicos clínicamente relevantes. Nuestro objetivo fue evaluar si la intensidad de captación de PSMA se asocia con el cáncer de próstata clínicamente significativo y poder conocer qué valor de captación de PSMA discrimina mejor esta relación. Métodos: Se realizó un estudio de cohorte de 40 pacientes con cáncer de próstata comprobado por biopsia previo a la realización de radioterapia externa. Se evaluó correlación entre intensidad de captación del PSMA intraprostático y los resulta dos patológicos adversos en la biopsia prostática. Se estudió qué valor de captación de PSMA discrimina mejor el cáncer de próstata clínicamente significativo utilizando curvas ROC. Resultados: El 40% de los pacientes tuvieron un cáncer de próstata clínicamente significativo, el maximum standardized uptake value (SUV max) tuvo una media de 11.5 (DE ± 7). La muestra arrojó un coeficiente de correlación Spearman de 0.4 (p = 0.007). El área bajo la curva (AUC) fue de 0.73, mostrando el punto de corte un SUV max ≥ 9.5, sensibilidad 0.81 y especificidad 0.71 en la detección de cáncer de próstata clínicamente significativo. Conclusión: la intensidad de captación del PSMA intraprostático puede ser una nueva herramienta diagnóstica en la detección del cáncer de próstata clínicamente significativo. Una intensidad de captación ≥ 9.5 tuvo una buena correlación con el cáncer de próstata clínicamente significativo.

Abstract Introduction: Positron emission tomography (PET) with prostate-specific membrane antigen (PSMA) improves prostate cancer staging. Furthermore, the intensity of intraprostatic uptake of PSMA can predict clinically relevant oncologic outcomes. The objective of this study is to evaluate whether the intensity of PSMA uptake is associated with clinically significant prostate cancer and to determine which value of PSMA uptake best dis criminates this relationship. Methods: A cohort study of 40 patients with biopsy-proven prostate cancer prior to external radiotherapy was conducted. The correlation between intraprostatic PSMA uptake intensity and adverse pathological findings in prostate biopsy was evaluated. Which PSMA uptake value better discriminates clinically significant prostate cancer was assessed using ROC curves. Results: Forty percent of the patients had a clinically significant prostate cancer and the maximum standardized uptake value (SUV max) had a mean of 11.5 (SD ± 7). The sample showed a Spearman correlation coefficient of 0.4 (p = 0.007). The area under the curve (AUC) was 0.73 and a SUV max ≥ 9.5 showed a sensitivity of 0.81 and a specificity of 0.71 in the detection of clinically significant prostate cancer. Conclusion: Intraprostatic PSMA uptake intensity can be a new diagnostic tool in the detection of clinically significant prostate cancer. An uptake intensity equal or greater than 9.5 is correlated with clinically significant prostate cancer.

Performance of 68Ga-labeled prostate-specific membrane antigen ligand positron emission tomography/computed tomography in the diagnosis of primary prostate cancer: a systematic review and meta-analysis

ABSTRACT Objective: To explore the feasibility of 68Ga-PSMA PET/CT in diagnosing primary prostate cancer. Materials and Methods: Embase, PubMed and Cochrane Library databases were searched for studies published before July 2020. The studies that used 68Ga-PSMA PET/CT for detecting primary prostate cancer, and pathological biopsy as the reference standard were included. The selecting process used preferred reporting items for systematic reviews and meta-analyses (PRISMA). The quality of enrolled studies was assessed by the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Results: According to our search strategy, 9 studies were included for analysis. A total of 547 patients with primary prostate cancer and 443 lesion segments that underwent 68Ga-PSMA PET/CT scans were included and their pathological biopsies were compared. The results of these studies showed some differences. For instance, the lowest sensitivity of 68Ga-PSMA PET/CT in diagnosing primary prostate cancer was 67%, while the highest sensitivity recorded was 97%. Conclusions: Compared with conventional imaging examinations, 68Ga-PSMA PET/CT had higher sensitivity and specificity in detecting primary prostate cancer. At present, most of the studies that used 68Ga-PSMA PET/CT for detecting prostate cancer are retrospective studies. Based on its advantage of high detection rate, the use of 68Ga-PSMA PET/CT in the detection of primary prostate cancer is worthy of promotion.

Use of PET/CT as a diagnostic tool in various clinical scenarios related to systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic disease mediated by immune complexes of unknown aetiology that generates excessive production of autoantibodies against components of the cell nucleus, generating multisystemic involvement affecting organs or systems such as the central nervous, cardiovascular, haematolymphoid, musculoskeletal, kidney, serous, skin and subcutaneous tissue cells, among others. 2-Fluoro-2-deoxyglucose (FDG) is a glucose analogue that has been shown to be a useful diagnostic tool to establish the initial systemic involvement of this disease and response to the various treatments used.

El lupus eritematoso sistémico (LES) es una enfermedad sistémica mediada por inmunocomplejos de etiología desconocida, la cual genera una producción excesiva de autoanticuerpos contra componentes del núcleo celular. Esto último conlleva un compromiso multisistémico que afecta a órganos o sistemas como el nervioso central, el cardiovascular, el hematolinfoide, el musculoesquelético, el rinón, las serosas, la piel y el tejido celular subcutáneo, entre otros. La 2-fluoro-2-desoxiglucosa (FDG) es un análogo de la glucosa que ha mostrado ser una herramienta diagnostica útil para establecer el compromiso sistémico inicial de esta enfermedad y la respuesta a los diversos tratamientos.

Interictal and postictal 18F-FDG PET/CT in epileptogenic zone localization.

Objective: To evaluate the performance of 18F-fluorodeoxyglucose positron-emission tomography/computed tomography ( 18F-FDG PET/CT) in localizing epileptogenic zones, comparing 18F-FDG injection performed in the traditional interictal period with that performed near the time of a seizure. Materials and Methods: We evaluated patients with refractory epilepsy who underwent 18F-FDG PET/CT. The reference standards for localization of the epileptogenic zone were histopathology and follow-up examinations (in patients who underwent surgery) or serial electroencephalography (EEG) recordings, long-term video EEG, and magnetic resonance imaging (in patients who did not). The 18F-FDG injection was performed whether the patient had an epileptic seizure during the EEG monitoring period or not. The 18F-FDG PET/CT results were categorized as concordant or discordant with the reference standards. Results: Of the 110 patients evaluated, 10 were in a postictal group (FDG injection after a seizure) and 100 were in the interictal group. The 18F-FDG PET/CT was concordant with the reference standards in nine (90%) of the postictal group patients and in 60 (60%) of the interictal group patients. Among the nine postictal group patients in whom the results were concordant, the 18F-FDG PET/CT showed hypermetabolism and hypometabolism in the epileptogenic zone in four (44.4%) and five (55.6%), respectively. Conclusion: Our data indicate that 18F-FDG PET/CT is a helpful tool for localization of the epileptogenic zone and that EEG monitoring is an important means of correlating the findings. In addition, postictal 18F-FDG PET/CT is able to identify the epileptogenic zone by showing either hypometabolism or hypermetabolism.

Objetivo: Avaliar a capacidade da PET/CT FDG detectar a zona epileptogênica, com injeção da FDG realizada tanto no período interictal como perto de uma crise epiléptica. Materiais e Métodos: Foram avaliados pacientes com epilepsia de difícil controle que realizaram PET/CT FDG. A zona epileptogênica foi definida pelo follow up/anatomopatológico ou eletroencefalogramas (EEGs) seriados, telemetria e ressonância magnética. PET/CT FDG foi realizada independentemente se o paciente tinha crise epiléptica durante a monitoração com EEG ou no período interictal. Os resultados foram definidos como concordantes ou discordantes, comparando com a zona epileptogênica. Resultados: Foram incluídos no estudo 110 pacientes: 10 no grupo pós-ictal (injeção de FDG depois da crise) e 100 no grupo interictal. A PET/CT FDG foi concordante com a zona epileptogênica em nove pacientes do grupo pós-ictal (90%) e 60 pacientes do grupo interictal (60%). Entre os nove pacientes concordantes do grupo pós-ictal, quatro mostraram hipermetabolismo (44,4%) e cinco mostraram hipometabolismo na zona epileptogênica (55,6%). Conclusão: Nossos resultados confirmaram que a PET/CT FDG é uma ferramenta útil na localização da zona epileptogênica e a monitoração com EEG é muito importante para correlacionar os achados. Além disso, PET/CT FDG realizada no período pós-ictal é capaz de identificar a zona epileptogênica, mostrando tanto hipometabolismo como hipermetabolismo.

Interictal and postictal 18F-FDG PET/CT in epileptogenic zone localization / PET/CT FDG- 18F interictal e pós-ictal na localização da zona epileptogênica

Abstract Objective: To evaluate the performance of 18F-fluorodeoxyglucose positron-emission tomography/computed tomography ( 18F-FDG PET/CT) in localizing epileptogenic zones, comparing 18F-FDG injection performed in the traditional interictal period with that performed near the time of a seizure. Materials and Methods: We evaluated patients with refractory epilepsy who underwent 18F-FDG PET/CT. The reference standards for localization of the epileptogenic zone were histopathology and follow-up examinations (in patients who underwent surgery) or serial electroencephalography (EEG) recordings, long-term video EEG, and magnetic resonance imaging (in patients who did not). The 18F-FDG injection was performed whether the patient had an epileptic seizure during the EEG monitoring period or not. The 18F-FDG PET/CT results were categorized as concordant or discordant with the reference standards. Results: Of the 110 patients evaluated, 10 were in a postictal group (FDG injection after a seizure) and 100 were in the interictal group. The 18F-FDG PET/CT was concordant with the reference standards in nine (90%) of the postictal group patients and in 60 (60%) of the interictal group patients. Among the nine postictal group patients in whom the results were concordant, the 18F-FDG PET/CT showed hypermetabolism and hypometabolism in the epileptogenic zone in four (44.4%) and five (55.6%), respectively. Conclusion: Our data indicate that 18F-FDG PET/CT is a helpful tool for localization of the epileptogenic zone and that EEG monitoring is an important means of correlating the findings. In addition, postictal 18F-FDG PET/CT is able to identify the epileptogenic zone by showing either hypometabolism or hypermetabolism.

Resumo Objetivo: Avaliar a capacidade da PET/CT FDG detectar a zona epileptogênica, com injeção da FDG realizada tanto no período interictal como perto de uma crise epiléptica. Materiais e Métodos: Foram avaliados pacientes com epilepsia de difícil controle que realizaram PET/CT FDG. A zona epileptogênica foi definida pelo follow up/anatomopatológico ou eletroencefalogramas (EEGs) seriados, telemetria e ressonância magnética. PET/CT FDG foi realizada independentemente se o paciente tinha crise epiléptica durante a monitoração com EEG ou no período interictal. Os resultados foram definidos como concordantes ou discordantes, comparando com a zona epileptogênica. Resultados: Foram incluídos no estudo 110 pacientes: 10 no grupo pós-ictal (injeção de FDG depois da crise) e 100 no grupo interictal. A PET/CT FDG foi concordante com a zona epileptogênica em nove pacientes do grupo pós-ictal (90%) e 60 pacientes do grupo interictal (60%). Entre os nove pacientes concordantes do grupo pós-ictal, quatro mostraram hipermetabolismo (44,4%) e cinco mostraram hipometabolismo na zona epileptogênica (55,6%). Conclusão: Nossos resultados confirmaram que a PET/CT FDG é uma ferramenta útil na localização da zona epileptogênica e a monitoração com EEG é muito importante para correlacionar os achados. Além disso, PET/CT FDG realizada no período pós-ictal é capaz de identificar a zona epileptogênica, mostrando tanto hipometabolismo como hipermetabolismo.

Patient with Rosai-Dorfman-Destombes disease:18F-FDG-PET/CT as a diagnostic tool

Rosai-Dorfman-Destombes disease (RDD) is a rare non-Langerhans cell histiocytosis, with sinus involvement and massive lymphadenopathy. RDD is usually self-limited; it can appear alone or related to other diseases. We present a 9-year-old male with biopsy of that lesion was taken, giving as result a benign histiocytosis, compatible with RDD. The patient was scanned with full body 18F-FDG PET/CT, the results of the study showed hypermetabolic focal lesions in the sphenoid sinus, ethmoid sinus, and bilateral nasal involvement with hypermetabolic focal injury in the middle third of the left tibia, findings in relation to high-grade expansive injury. The study of 18F-FDG PET/CT demonstrated avid FDG lesions at nodal and extranodal sites, and it also can be used in monitoring and/or evaluating response to treatment.

La enfermedad de Rosai-Dorfman-Destombes (RDD) es una rara histiocitosis de células no Langerhans, con compromiso de los senos nasales y linfadenopatías masivas. RDD es usualmente autolimitada, y puede aparecer sola o asociada a otras enfermedades. Se presenta el caso de un niño varón de 9 años cuyo resultado histopatológico mostró histiocitosis benigna compatible con RDD. El paciente se sometió a una Tomografía Computarizada/Tomografía de Emisión de Positrones con 18F-fluorodeoxyglucosa (18F-FDG-TEP/TC) de todo el cuerpo, que mostró lesiones focales hipermetabólicas en los senos esfenoidales, etmoidales, y nasales bilaterales, junto a una lesión focal hipermetabólica en el tercio medio de la tibia izquierda. El estudio con 18F-FDG-PET/CT pudo demostrar lesiones ávidas de glucosa en sitios nodales y extra-nodales, y también puede servir en la monitorización o evaluación de la respuesta al tratamiento.

Lithium Intoxication as a cause of reversible dementia mimicking FDG PET features of Alzheimer's disease.

Rapidly progressive dementia (RPD) is a rare neurological disorder. Drug toxicity is among the differential diagnoses, including the use of lithium, in which an overdosage might cause cognitive dysfunction. Clinical suspicion, laboratory confirmation, and drug interruption are key points in the management of lithium intoxication. We described a 66-year-old female patient under treatment with lithium who developed an RPD associated with parkinsonian symptoms. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) showed an "Alzheimer-like" pattern, while cerebrospinal fluid biomarkers for the disease were negative. There was a significant clinical and radiological improvement after lithium interruption. Lithium intoxication is a potentially reversible cause of RPD, as demonstrated in this case report. Drug discontinuation should be considered even in patients with normal levels of this metal, if cognitive impairment is detected. 18F-FDG PET/CT images may show an "Alzheimer-like" image pattern in acute intoxication and are useful for monitoring these patients.

Demência rapidamente progressiva é uma condição rara, cujos diagnósticos diferenciais incluem intoxicação por drogas como lítio, podendo causar importante disfunção cognitiva. A suspeita clínica, a confirmação laboratorial e a interrupção do uso medicamentoso são elementos fundamentais em seu diagnóstico e manejo. Trata-se de paciente feminina, de 66 anos de idade, que apresentou quadro demencial após intoxicação por lítio. Tal quadro foi acompanhado de sintomas parkinsonianos, além de Tomografia por Emissão de Pósitrons com 18F-Fluodeoxiglicose (18F-FDG PET/CT) compatível com padrão "Alzheimer-like". Houve melhora objetiva de parâmetros clínicos e imaginológicos após a interrupção do uso medicamentoso. A intoxicação por lítio é uma causa potencialmente reversível de demência rapidamente progressiva. A descontinuação da droga deve ser considerada também em pacientes com níveis normais do metal no sangue se alterações cognitivas forem encontradas. Imagens 18F-FDG PET/CT podem demonstrar achados sugestivos de doença de Alzheimer na intoxicação aguda e parecem ser um método útil no seguimento.