Quantitative analysis of the effect of the magnetic field generated by a PET/MR scanner on positron range.

OBJECTIVE: Image quality in positron emission tomography (PET) is influenced by positron range. In this work, the effect of the magnetic field of a PET/MR Siemens Biograph mMR 3T on the quality of PET images was studied. APPROACH: Experimental measurements were conducted using18F and68Ga-filled phantoms to quantify image uniformity, recovery coefficients (RCs), spill-over ratios and percent contrast for spherical lesions. Tissue-equivalent phantoms (lung inhale and exhale, adipose, water, trabecular and cortical bone) were used together with a line source to quantify the impact of the magnetic field on the reconstructed PET images. A comparative analysis was made with images obtained with a PET/CT Biograph Vision 600, using the same radionuclides and phantoms. MAIN RESULTS: Higher RCs values were obtained when the image quality phantom was filled with68Ga and scanned with the PET/MR system compared to those obtained with the PET/CT scanner. Hot spheres in the lesion detectability phantom, appear contracted in the transverse direction in the PET/MR system, an effect more evident for68Ga compared to18F, but no elongation in the direction parallel to the magnetic field was observed. In the PET/CT scanner, radial profiles taken from axial slices of line sources, show longer distribution tails extending beyond 20 mm when filled with68Ga and placed inside lung-inhale tissue. In the PET/MR scanner the radial profiles of all materials collapsed into a single distribution with tails extending no more than 10 mm in the direction perpendicular to the magnetic field. SIGNIFICANCE: Positron range depends on positron energy and material density in which they traverse. The results show an evident improvement in image quality in the transaxial direction only, particularly in phantoms filled with68Ga when using a PET/MR system as opposed to images acquired in the PET/CT system due to the presence of the magnetic field.

MR1 blockade drives differential impact on integrative signatures based on circuits of circulating immune cells and soluble mediators in visceral leishmaniasis.

Introduction: Visceral leishmaniasis (VL) is an important tropical and neglected disease and represents a serious global health problem. The initial interaction between the phagocytes and the parasite is crucial to determine the pathogen's capacity to initiate infection and it shapes the subsequent immune response that will develop. While type-1 T-cells induce IL-6, IL-1ß, TNF-α, and IL-12 production by monocytes/macrophages to fight the infection, type-2 T-cells are associated with a regulatory phenotype (IL-10 and TGF-ß) and successful infection establishment. Recently, our group demonstrated the role of an important Th1/Th17 T-cell population, the mucosal-associated invariant T (MAIT) cells, in VL. MAIT cells can respond to L. infantum by producing TNF-α and IFN-γ upon MR1-dependent activation. Objective and methods: Here, we describe the impact of the MR1-blockage on L. infantum internalization on the functional profile of circulating neutrophils and monocytes as well as the impact of the MR1-blockage on the soluble mediator signatures of in vitro whole blood cultures. Results: Overall, our data showed that VL patients presents higher percentage of activated neutrophils than asymptomatic and non-infected controls. In addition, MR1 blockade led to lower TNF-α and TGF-ß production by non-activated neutrophils from asymptomatic individuals. Moreover, TNF-α and IL-10 production by monocytes was higher in VL patients. In the analysis of soluble mediators produced in vitro, MR1-blockade induced a decrease of IFN-γ and an increase of IL-10, IL-27 and IL-33 in the cell cultures of AS group, a cytokine pattern associated with type 2 deleterious response. Discussion and conclusion: These data corroborate the hypothesis that MR1-restricted responses are associated to a protective role during Leishmania infection.

Deuterium MR spectroscopy: potential applications in oncology research.

Metabolic imaging in clinical practice has long relied on PET with fluorodeoxyglucose (FDG), a radioactive tracer. However, this conventional method presents inherent limitations such as exposure to ionizing radiation and potential diagnostic uncertainties, particularly in organs with heightened glucose uptake like the brain. This review underscores the transformative potential of traditional deuterium MR spectroscopy (MRS) when integrated with gradient techniques, culminating in an advanced metabolic imaging modality known as deuterium MRI (DMRI). While recent advancements in hyperpolarized MRS hold promise for metabolic analysis, their widespread clinical usage is hindered by cost constraints and the availability of hyperpolarizer devices or facilities. DMRI, also denoted as deuterium metabolic imaging (DMI), represents a pioneering, single-shot, and noninvasive paradigm that fuses conventional MRS with nonradioactive deuterium-labelled substrates. Extensively tested in animal models and patient cohorts, particularly in cases of brain tumours, DMI's standout feature lies in its seamless integration into standard clinical MRI scanners, necessitating only minor adjustments such as radiofrequency coil tuning to the deuterium frequency. DMRI emerges as a versatile tool for quantifying crucial metabolites in clinical oncology, including glucose, lactate, glutamate, glutamine, and characterizing IDH mutations. Its potential applications in this domain are broad, spanning diagnostic profiling, treatment response monitoring, and the identification of novel therapeutic targets across diverse cancer subtypes.

Commissioning of MRI-guided gynaecological brachytherapy using an MR-linac.

Purpose. To evaluate the feasibility of use of an 1.5 T magnetic resonance (MR)-linear accelerator MR-linac for imaging in gynaecologic high-dose-rate (HDR) brachytherapy.Method. Commissioning measurements for MR images quality control, geometric distortion, dwell position accuracy, applicator reconstruction and end-to-end test for a tandem-and-ring applicator were performed following the recommendations of American Brachytherapy Society, International Commission on Radiation Units and Measurements and Report of the Brachytherapy Working Group of the Spanish Society of Medical Physics. The values for MR-based IGABT were compared to the corresponding values with computed tomography (CT).Results. Measured distorsions for the MR images were less than 0.50 mm compared to the CT images. The differences between 3D displacements for all dwell positions were 0.66 mm and 0.62 mm for the tandem and ring, respectively. The maximum difference is 0.64 mm for the distances from the applicator tip obtained using the films. The CT and MR dose differences for the right and left 'A' points were 0.9% and -0.7%, respectively. Similar results were observed in terms of dose distribution for CT and Mr The gamma passing rate was 99.3% and 99.5%, respectively.Conclusion. The use of MR images from an MR-linac used in a radiotherapy service for gynaecological brachytherapy was proved to be feasible, safe and precise as the geometrical differences were less than 1 mm, and the dosimetric differences were less than 1% when comparing to the use of CT images for the same purpose.

Risk of positive screening for anorexia nervosa, bulimia nervosa and night eating syndrome and associated risk factors in medical fellows in Northeastern Mexico: a multicenter study.

BACKGROUND: Eating disorders and food ingestion (EDs) are serious mental illnesses with a higher prevalence in young adults, with difficult diagnoses that cause serious morbidity and mortality problems. There is not much information about the risk of positive screening for EDs, specifically, anorexia nervosa (AN) and bulimia nervosa (BN) and night eating syndrome (NES) in undergraduate medical interns (UMI) and medical residents (MR) in Mexico. AIM: To determine the risk of AN, BN and NES and to determine the risk factors of such conditions such as age, body mass index (BMI) and gender of MR and UMI with AN/BN and NES at four private hospitals in northeastern Mexico. METHODS: A cross-sectional, descriptive, non-randomized survey in MR and UMI in four hospitals in Northeastern Mexico was conducted using an electronic questionnaire that included: informed consent signature, SCOFF questionnaire for AN and BN screening, NES questionnaire. Also, a survey on general sociodemographic data of each participant was included. Chi-square test and a logistic regression model were computed for analyses. RESULTS: The population included a total of 129 MR and UMI. It was observed that 48.8% were positive for AN or BN and 32.6% were positive for the NES. There was no difference between age, sex, BMI, or medical specialty (if they were MR); however, MR from the first year had a higher risk of AN or BN (OR 23.7, 95% CI 1.181-475.266). CONCLUSIONS: There was a higher risk of positive screening for AN or BN and NES in UMI and MR in our population. In the case of MR, those in first year have a higher risk of AN and BN. Timely diagnosis and treatment are mandatory in this population.

Eating disorders and food ingestion such as anorexia (AN) or bulimia (BN) nervosa and night eating syndrome (NES) are a group of mental illnesses that are frequently under diagnosed. Medical residents (MR) and undergraduate medical interns (UMI) are a high-risk population for such disorders due to their young age, stress environments, erratic eating patterns and long working hours. The aim of this study was to determine the risk of AN, BN and NES and to determine the risk factors of such conditions. One hundred twenty-nine UMI and MR were studied and showed that 48.8% were positive for AN or BN and 32.6% were positive for NES. MR in the first year of medical residency had a higher risk. Timely diagnosis and treatment are mandatory in this population.

Neuropathy Score Reporting and Data System (NS-RADS): A Practical Review of MRI-Based Peripheral Neuropathy Assessment.

The Neuropathy Score Reporting and Data System (NS-RADS) is a newly developed MR imaging-based classification that standardizes reporting and multidisciplinary communication for MR imaging diagnosis and follow-up of peripheral neuropathies. NS-RADS classification has shown to be accurate and reliable across different centers, readers' experience levels, and degrees of peripheral neuropathies, which include nerve injury, entrapment, neoplasm, diffuse neuropathy, post-interventional status, and temporal changes in muscle denervation. This article brings a practical review of NS-RADS classification, representative MR cases, and a step-by-step tutorial on how to approach this staging system. Readers can gain knowledge and apply it in their practice, aiming to standardize the communications between specialties and improve patient management.

The insula mediates the effects of glucocorticoids in anxiety.

Increased activity in the insula has been consistently reported to be associated with anxiety and anxiety-related disorders. However, little is known on how the insula regulates anxiety. The present study aims at determining the role of the insula on the effects of glucocorticoids in anxiety. A combination of pharmacological manipulations, including blockade of adrenal GC synthesis by metyrapone and intra-insular microinjections of corticosterone, corticosterone-BSA, mineralocorticoid receptor (MR) antagonist spironolactone and glucocorticoid receptor (GR) antagonist mifepristone, were used to assess the short-term (5 min) effects of intra-insular corticosterone in two anxiety-like behaviors in male Sprague-Dawley rats. The elevated plus maze (EPM) and Novelty Suppressed Feeding (hyponeophagia) were utilized. We found that corticosterone in the insula is sufficient to prevent the anxiolytic effects corticosterone synthesis blockade in anxiety, and that intra-insular corticosterone has anxiolytic or anxiogenic effects depending on the amount of corticosterone microinjected and the arousal associated to the test, without affecting the HPA axis. Glucocorticoid anxiolytic effects in the insula are mediated by MRs, while its anxiogenic effects are dependent on a mifepristone-sensitive membrane-bound mechanism. Anxiety appears to be modulated at the insula through a competition between fast MR-dependent anxiolytic and membrane-associated anxiogenic signaling pathways that orchestrate the behavioral response to stress and determines the resulting level of anxiety.

Historia de la medicina chilena: ¿Cómo, dónde y cuándo habría nacido la cirugía moderna chilena? / ¿How, where and when modern chilean surgery would have been born?

The challenge of knowing the events surrounding the modern origins of the different specialties of Chilean medicine should be of interest to the specialists of these specialties. Thus, in the case of surgery, fortunately in Chile there are testimonial documents, which reviewed and analyzed can suggest this question, mentioning the one who today is considered the world father of modern surgery, whose important surgical teachings were delivered to Chilean disciples who introduced it in our country. In the context of the War of the Pacific, in the year 1879, a "blood hospital" was built in Santiago, donated by Domingo Matte, a Chilean politician, to receive the many war wounded who were transported from the north. It was Dr. Manuel Barros Borgoño, a young surgeon recently graduated from the Faculty of Medicine in Paris, with a degree revalidated in Chile, who in 1880 took charge of this hospital, and together with his team, began to apply his experience in listerian methods learned in Paris from his teacher Dr. Just Lucas Champonniere. Just Lucas Champonniere, giving beginning to the Chilean antiseptic surgery, managing to reduce the mortality of surgeries to 3%, compared to 80% of other Chilean hospitals that refused to change, and continued with the use of sponge soaked in cerato (lard).

IMPACTO-MR: um estudo brasileiro de plataforma nacional para avaliar infecções e multirresistência em unidades de terapia intensiva / IMPACTO-MR: a Brazilian nationwide platform study to assess infections and multidrug resistance in intensive care units

RESUMO Objetivo: Descrever o IMPACTO-MR, um estudo brasileiro de plataforma nacional em unidades de terapia intensiva focado no impacto das infecções por bactérias multirresistentes relacionadas à assistência à saúde. Métodos: Descrevemos a plataforma IMPACTO-MR, seu desenvolvimento, critérios para seleção das unidades de terapia intensiva, caracterização da coleta de dados, objetivos e projetos de pesquisa futuros a serem realizados na plataforma. Resultados: Os dados principais foram coletados por meio do Epimed Monitor System® e consistiram em dados demográficos, dados de comorbidades, estado funcional, escores clínicos, diagnóstico de internação e diagnósticos secundários, dados laboratoriais, clínicos e microbiológicos e suporte de órgãos durante a internação na unidade de terapia intensiva, entre outros. De outubro de 2019 a dezembro de 2020, 33.983 pacientes de 51 unidades de terapia intensiva foram incluídos no banco de dados principal. Conclusão: A plataforma IMPACTO-MR é um banco de dados clínico brasileiro de unidades de terapia intensiva focado na pesquisa do impacto das infecções por bactérias multirresistentes relacionadas à assistência à saúde. Essa plataforma fornece dados para o desenvolvimento e pesquisa de unidades de terapia intensiva individuais e ensaios clínicos observacionais e prospectivos multicêntricos.

ABSTRACT Objective: To describe the IMPACTO-MR, a Brazilian nationwide intensive care unit platform study focused on the impact of health care-associated infections due to multidrug-resistant bacteria. Methods: We described the IMPACTO-MR platform, its development, criteria for intensive care unit selection, characterization of core data collection, objectives, and future research projects to be held within the platform. Results: The core data were collected using the Epimed Monitor System® and consisted of demographic data, comorbidity data, functional status, clinical scores, admission diagnosis and secondary diagnoses, laboratory, clinical, and microbiological data, and organ support during intensive care unit stay, among others. From October 2019 to December 2020, 33,983 patients from 51 intensive care units were included in the core database. Conclusion: The IMPACTO-MR platform is a nationwide Brazilian intensive care unit clinical database focused on researching the impact of health care-associated infections due to multidrug-resistant bacteria. This platform provides data for individual intensive care unit development and research and multicenter observational and prospective trials.

Case report: Takayasu arteritis in a newborn, 5-years follow-up

Takayasu Arteritis (TA) is classified as a large vessel vasculitis, it primarily affects aorta and principal branches. The clinical presentation in pediatric patients is odd and there a few literature about it. The case is about a feminine patient hospitalized after birth with diagnosis of patent ductus arterious (PDA), abnormal widening of the descending aorta, aneurysm of the aortic arch. It is kept under close surveillance for 5 years, with imaging improvement in treatment with methotrexate and immunoglobulin, however she presented relapses on two occasions where the caliber decreased in descending aorta and left iliac artery. We can conclude that Identifying AT findings is important for early diagnosis, medical management, and proper monitoring specifically in pediatric patients where little literature is available.

La arteritis de Takayasu (AT) se clasifica como una vasculitis de grandes vasos desarrollándose sobre todo en aorta y ramas principales. Su presentación en pacientes pediátricos es rara y existe muy poca información en la literatura. Se trata de una paciente femenina hospitalizada al nacimiento, a quien se diagnostica ductus arterioso persistente (DAP), dilatación de aorta descendente y aneurisma de arco aórtico. Se mantiene bajo vigilancia estrecha durante cinco arios, con mejoría imagenológica en tratamiento a base metrotexato e inmunoglobulina, sin embargo, presenta recaídas en dos ocasiones, donde se observa disminución del calibre de aorta descendente y arteria iliaca izquierda. Se puede concluir que el identificar los hallazgos de la AT es importante para realizar un diagnóstico temprano, manejo médico oportuno y vigilancia adecuada, en específico en pacientes pediátricos, de quienes se tiene poca información en la literatura.

PET/MR: primary inferior vena cava leiomyosarcoma.

Positron emission tomography (PET) combined with a magnetic resonance (MR) scanner (PET/MR) with 18F-fluorodeoxyglucose (FDG) tracer is being used in quite a few nuclear medicine centers. The aim of this study is to illustrate two uncommon cases of primary inferior vena cava leiomyosarcoma which were formerly evaluated with anatomical images such as computed tomography and ultrasound. These techniques were inferior in the definition of the tumor and its characteristics. F-18 FDG PET/MR was essential and provided all the necessary information: its origin, local extension, anatomo-metabolic behavior, form of presentation, and distant metastasis in one single diagnostic technique. PET/MR accurately contributed to the diagnosis in a shortened period of time and, therefore, in the prognosis of this disease with greater benefits.

Differential Diagnosis of Major Depressive Disorder and Bipolar Disorder: Genetic and Hormonal Assessment and the Influence of Early-Life Stress.

Few studies have assessed biomarkers for the differentiation of major depressive disorder (MDD) and bipolar disorder (BD). However, some elements of depression such as hormones and receptors of the renin-angiotensin-adrenal system (RAAS), the hypothalamus-pituitary-adrenal (HPA) axis, and history of early-life stress (ELS) could be considered for differential diagnosis. Therefore, this study aimed to assess aldosterone and cortisol levels, MR and GR gene polymorphisms, and ELS as potential biomarkers for differentiating MDD and BD. This study presents a case-control design. Groups comprised samples for genetic, cortisol, and aldosterone analysis: healthy control (HC; n = 113/97/103), MDD (n = 78/69/67) and BD (n = 82/68/65) subjects. Furthermore, all subjects were assessed for diagnostic screening, the severity of depression, and history of ELS by applying MINI-PLUS, GRID-HDRS, and CTQ, respectively. In addition, genotype and allelic frequencies of GR (N363S, R22/23K and BclI) and MR (MI180V and -2G/C) polymorphisms were evaluated via PCR. Our findings demonstrate that basal aldosterone levels may be a biomarker for differentiating BD and MDD. Furthermore, ELS affects the HPA axis in BD, cortisol may be considered a biomarker for distinguishing BD and MDD, but only in the absence of ELS, and, finally, history of ELS and MR-2G/C variant alleles are factors that contribute to the severity of depressive symptoms in MDD and BD.

The role of mucosal-associated invariant T cells in visceral leishmaniasis.

Mucosal-associated invariant T (MAIT) cells are restricted by MR1 and are known to protect against bacterial and viral infections. Our understanding of the role of MAIT cells in parasitic infections, such as visceral leishmaniasis (VL) caused by protozoan parasites of Leishmania donovani, is limited. This study showed that in response to L. infantum, human peripheral blood MAIT cells from children with leishmaniasis produced TNF and IFN-γ in an MR1-dependent manner. The overall frequency of MAIT cells was inversely correlated with alanine aminotransferase levels, a specific marker of liver damage strongly associated with severe hepatic involvement in VL. In addition, there was a positive correlation between total protein levels and the frequency of IL-17A+ CD8+ MAIT cells, whereby reduced total protein levels are a marker of liver and kidney damage. Furthermore, the frequencies of IFN-γ+ and IL-10+ MAIT cells were inversely correlated with hemoglobin levels, a marker of severe anemia. In asymptomatic individuals and VL patients after treatment, MAIT cells also produced IL-17A, a cytokine signature associated with resistance to visceral leishmaniasis, suggesting that MAIT cells play important role in protecting against VL. In summary, these results broaden our understanding of MAIT-cell immunity to include protection against parasitic infections, with implications for MAIT-cell-based therapeutics and vaccines. At last, this study paves the way for the investigation of putative MAIT cell antigens that could exist in the context of Leishmania infection.

Semiactive Knee Orthotic Using a MR Damper and a Smart Insole to Control the Damping Force Sensing the Plantar Pressure.

This work presents the development of semiactive knee orthosis prototype that focus to absorb the forces and impacts in this joint during the human gait. This prototype consists of three subsystems: the first is a wireless and portable system capable of measuring the ground reaction forces in the stance phase of the gait cycle, by means of an instrumented insole with force sensing resistors strategically placed on the sole of the foot, an electronic device allows processing and transmit this information via Bluetooth to the control system. The second is a semiactive actuator, which has inside a magnetorheological fluid, highlighting its ability to modify its damping force depending on the intensity of the magnetic field that circulates through the MR fluid. It is regulated by a Proportional Derivative (PD) controller system according to the values of plantar pressure measured by the insole. The third component is a mechanical structure manufactured by 3D printing, which adapts to the morphology of the human leg. This exoskeleton is designed to support the forces on the knee controlling the action of the magnetorheological actuator by ground reaction forces. The purpose of this assistance system is to reduce the forces applied to the knee during the gait cycle, providing support and stability to this joint. The obtained experimental results indicate that the device fulfills the function by reducing 12 % of the impact forces on the user's knee.

Multicenter Repeatability and Reproducibility of MR Fingerprinting in Phantoms and in Prostatic Tissue.

PURPOSE: To evaluate multicenter repeatability and reproducibility of T1 and T2 maps generated using MR fingerprinting (MRF) in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI system phantom and in prostatic tissues. METHODS: MRF experiments were performed on 5 different 3 Tesla MRI scanners at 3 different institutions: University Hospitals Cleveland Medical Center (Cleveland, OH), Brigham and Women's Hospital (Boston, MA) in the United States, and Diagnosticos da America (Rio de Janeiro, RJ) in Brazil. Raw MRF data were reconstructed using a Gadgetron-based MRF online reconstruction pipeline to yield quantitative T1 and T2 maps. The repeatability of T1 and T2 values over 6 measurements in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI system phantom was assessed to demonstrate intrascanner variation. The reproducibility between the 4 clinical scanners was assessed to demonstrate interscanner variation. The same-day test-retest normal prostate mean T1 and T2 values from peripheral zone and transitional zone were also compared using the intraclass correlation coefficient and Bland-Altman analysis. RESULTS: The intrascanner variation of values measured using MRF was less than 2% for T1 and 4.7% for T2 for relaxation values, within the range of 307.7 to 2360 ms for T1 and 19.1 to 248.5 ms for T2 . Interscanner measurements showed that the T1 variation was less than 4.9%, and T2 variation was less than 8.1% between multicenter scanners. Both T1 and T2 values in in vivo prostatic tissue demonstrated high test-retest reliability (intraclass correlation coefficient > 0.92) and strong linear correlation (R2  > 0.840). CONCLUSION: Prostate MRF measurements of T1 and T2 are repeatable and reproducible between MRI scanners at different centers on different continents for the above measurement ranges.

Acquired Peripheral Nerve Injury Findings in Critically Ill COVID-19 Patients.

We retrospectively analyzed clinical, NCS/EMG, and NMRI aspects of five COVID-19 intensive care unit inpatients that received mechanical ventilation. After awakening from sedation, they experienced peripheral neuromyopathic symptoms. Teaching Point: Acquired peripheral nerve injury has been described in COVID-19 infection and knowledge of the clinical, nerve conduction studies/electromyography (NCS/EMG) and neurographic magnetic resonance imaging (NMRI) findings are crucial.

Future assessment of the impact of the COVID-19 pandemic on the electricity market based on a stochastic socioeconomic model.

This paper proposes a time-series stochastic socioeconomic model for analyzing the impact of the pandemic on the regulated distribution electricity market. The proposed methodology combines the optimized tariff model (socioeconomic market model) and the random walk concept (risk assessment technique) to ensure robustness/accuracy. The model enables both a past and future analysis of the impact of the pandemic, which is essential to prepare regulatory agencies beforehand and allow enough time for the development of efficient public policies. By applying it to six Brazilian concession areas, results demonstrate that consumers have been/will be heavily affected in general, mainly due to the high electricity tariffs that took place with the pandemic, overcoming the natural trend of the market. In contrast, the model demonstrates that the pandemic did not/will not significantly harm power distribution companies in general, mainly due to the loan granted by the regulator agency, named COVID-account. Socioeconomic welfare losses averaging 500 (MR$/month) are estimated for the equivalent concession area, i.e., the sum of the six analyzed concession areas. Furthermore, this paper proposes a stochastic optimization problem to mitigate the impact of the pandemic on the electricity market over time, considering the interests of consumers, power distribution companies, and the government. Results demonstrate that it is successful as the tariffs provided by the algorithm compensate for the reduction in demand while increasing the socioeconomic welfare of the market.

Elastografia por ressonância magnética para avaliação de doença hepática gordurosa não alcoólica / Magnetic resonance elastography for evaluation of non-alcoholic fatty liver disease

Introdução: A doença hepática gordurosa não alcoólica (DHGNA) é uma das causas mais comuns de hepatopatia. Devido ao grande risco de progressão para cronicidade, seu rastreamento se faz necessário. A Elastografia por Ressônancia Magnética (MRE) foi estabelecida em diversos estudos como uma técnica acurada para o diagnóstico de fibrose. Objetivos: Descrever a prevalência de esteatose e de fibrose hepática em pacientes com DHGNA submetidos à MRE; estimar o grau de fibrose, correlacionando com a escala METAVIR, e avaliar a fração de gordura por densidade de prótons (PDFF) e os fatores clínicos associados à esteatose e fibrose. Métodos: Estudo transversal, realizado mediante revisão de imagens de MRE, entre janeiro de 2017 e março de 2019, em um hospital da região sul do Brasil. Resultados: Dos 298 pacientes incluídos, a maioria dos pacientes apresentava esteatose leve (41,6%, n=124) ou ausente (30,9%, n=92), enquanto 15,1% (n=45) apresentava esteatose moderada e 12,4% (n=37), acentuada. A maioria dos pacientes (65,8%, n=181) apresentava rigidez hepática dentro da normalidade, 11,6% (n=32) inflamação crônica, 7,6% (n=21) fibrose estágio 1-2, 3,6% (n=10) fibrose estágio 2-3, 4,7% (n=13) fibrose estágio 3-4 e 6,5% (n=18) fibrose estágio 4 ou cirrose. Discussão: Os resultados encontrados nesta amostra reforçam os fatores de risco para o desenvolvimento de DHGNA previamente avaliados. Uma combinação de estratégias não invasivas, incluindo a MRE, poderá selecionar os pacientes com maior probabilidade de agravos. Conclusão: Nesse estudo, a maioria dos pacientes apresentou a forma leve ou ausência de esteatose e rigidez hepática dentro da normalidade. A MRE tem se mostrado uma técnica altamente acurada, não invasiva para estadiamento de fibrose hepática em pacientes com DHGNA, sem influência significativa da idade, sexo, adiposidade e grau de inflamação hepática.

Introduction: Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of liver disease. Due to the high risk of progression to chronicity, its tracking is necessary. Magnetic Resonance Elastography (MRE) has been established in several studies as an accurate technique for diagnosing fibrosis. Objectives: To describe the prevalence of steatosis and liver fibrosis in NAFLD patients undergoing MRE; estimate the degree of fibrosis, correlating with the METAVIR scale, and assess the proton density fat-fraction (PDFF). Methods: A cross-sectional study, performed by reviewing MRE images, between January 2017 and March 2019, in a hospital in southern Brazil. Results: Of the 298 patients included, most patients had mild (41.6%, n=124) or absent (30.9%, n=92) steatosis, while 15.1% (n=45) had moderate and 12.4% (n=37) marked steatosis. Most patients (65.8%, n=181) had liver stiffness within the normal range, 11.6% (n=32) chronic inflammation, 7.6% (n=21) stage 1-2 fibrosis, 3.6% (n=10) stage 2-3 fibrosis, 4.7% (n=13) stage 3-4 fibrosis, and 6.5% (n=18) stage 4 fibrosis or cirrhosis. Discussion: The results found in this sample reinforce the risk factors for the development of NAFLD previously evaluated. A combination of non-invasive strategies, including MRE, may select the patients with the greatest likelihood of harm. Conclusions: MRE has been shown to be a highly accurate, non-invasive technique for staging liver fibrosis in NAFLD patients, with no significant influence of age, sex, adiposity, and degree of liver inflammation.