Evaluation of pneumatosis intestinalis as a complication of lung transplantation.

INTRODUCTION: Pneumatosis intestinalis is a radiological finding characterized by the presence of gas in the bowel wall that is associated with multiple entities. Our aim is to know its incidence in lung transplant patients, its physiopathology and its clinical relevance. METHODS: A search of patients with pneumatosis intestinalis was performed in the database of the Lung Transplant Unit of our hospital. The presence of pneumatosis after transplantation was confirmed in all of them and relevant demographic, clinical and imaging variables were collected to evaluate its association and clinical expression, as well as the therapeutic approach after the findings. RESULTS: The incidence of pneumatosis intestinalis after lung transplantation in our center was 3.1% (17/546), developing between 9 and 1270 days after transplantation (mean, 198 days; median 68 days). Most of the patients were asymptomatic or with mild symptoms, without any major analytical alterations, and with a cystic and expansive radiological appearance. Pneumoperitoneum was associated in 70% of the patients (12/17). Conservative treatment was chosen in all cases. The mean time to resolution was 389 days. CONCLUSION: Pneumatosis intestinalis in lung transplant patients is a rare complication of uncertain origin, which can appear for a very long period of time after transplantation. It has little clinical relevance and can be managed without other diagnostic or therapeutic interventions.

Prevalence of burnout syndrome in Spanish radiologists.

BACKGROUND AND AIMS: The primary objective was to analyze the prevalence and degree of professional burnout in radiologists in Spain. Secondary objectives were to identify possible factors that increase or decrease the risk of burnout to enable preventive and corrective measures, decrease the stress associated with this condition, and thereby increase radiologists' performance and satisfaction at work. MATERIAL AND METHODS: This cross-sectional observational study used a voluntary, anonymous online survey of attending radiologists and residents through Google Forms®. The survey was structured into three sections: a qualitative assessment of the degree of professional burnout with the Maslach Burnout Inventory Human Services Survey (MBI-HSS), a series of sociodemographic and work-related questions, and a final section centered on possible causes of stress and improvements to the working environment. The results of the survey were analyzed statistically to determine which variables were associated with burnout syndrome as well as to identify possible risk factors and protective factors. RESULTS: After disseminating the survey through social networks and email contacts, we received a total of 226 responses (175 from attending radiologists and 51 from residents; 52% men; mean age, 41 ± 11 years; age range, 25-68). The prevalence of the syndrome was 33%, without significant differences between attending radiologists and residents. No risk factors associated with burnout were identified. Teaching in the workplace was the only protective factor. CONCLUSIONS: One-third of the respondents had burnout syndrome. Because the consequences of this syndrome can affect professionals' personal life and their ability to do their jobs, early detection and intervention should be prioritized.

Development of severity and mortality prediction models for covid-19 patients at emergency department including the chest x-ray.

OBJECTIVES: To develop prognosis prediction models for COVID-19 patients attending an emergency department (ED) based on initial chest X-ray (CXR), demographics, clinical and laboratory parameters. METHODS: All symptomatic confirmed COVID-19 patients admitted to our hospital ED between February 24th and April 24th 2020 were recruited. CXR features, clinical and laboratory variables and CXR abnormality indices extracted by a convolutional neural network (CNN) diagnostic tool were considered potential predictors on this first visit. The most serious individual outcome defined the three severity level: 0) home discharge or hospitalization ≤ 3 days, 1) hospital stay >3 days and 2) intensive care requirement or death. Severity and in-hospital mortality multivariable prediction models were developed and internally validated. The Youden index was used for the optimal threshold selection of the classification model. RESULTS: A total of 440 patients were enrolled (median 64 years; 55.9% male); 13.6% patients were discharged, 64% hospitalized, 6.6% required intensive care and 15.7% died. The severity prediction model included oxygen saturation/inspired oxygen fraction (SatO2/FiO2), age, C-reactive protein (CRP), lymphocyte count, extent score of lung involvement on CXR (ExtScoreCXR), lactate dehydrogenase (LDH), D-dimer level and platelets count, with AUC-ROC = 0.94 and AUC-PRC = 0.88. The mortality prediction model included age, SatO2/FiO2, CRP, LDH, CXR extent score, lymphocyte count and D-dimer level, with AUC-ROC = 0.97 and AUC-PRC = 0.78. The addition of CXR CNN-based indices did not improve significantly the predictive metrics. CONCLUSION: The developed and internally validated severity and mortality prediction models could be useful as triage tools in ED for patients with COVID-19 or other virus infections with similar behaviour.

Prevalence of burnout syndrome during the COVID-19 pandemic and associated factors.

BACKGROUND: The coronavirus 2019 (COVID-19) epidemic spread throughout the world from the beginning of 2020, increasing healthcare professionals' workloads and levels of physical and emotional stress. AIMS: To determine the prevalence of burnout syndrome in Spanish radiologists during the COVID-19 pandemic and the factors associated with the development of this syndrome, and to compare these findings with those obtained before the pandemic. METHODS: This observation study took place between April 2020 and August 2020 (during the pandemic) through an online survey. A total of 150 responses were obtained. Demographic and work-related information was compiled. Burnout syndrome was measured with the Maslach Burnout Inventory Human Services Survey (MBI-HSS). The prevalence and characteristics of burnout syndrome obtained in this survey were compared with those of the same survey done in 2019. We performed a statistical analysis to identify possible risk factors and protective factors associated with this syndrome and to determine the homogeneity of the two samples. RESULTS: The prevalence of burnout syndrome increased during the COVID-19 pandemic (49.3% vs. 33.6%, p = 0.002). No risk factors or protective factors that were valid both before and after the pandemic were identified. No correlations were identified between sociodemographic or work-related characteristics and burnout syndrome. CONCLUSION: This study demonstrates that burnout syndrome increased significantly in radiologists during the COVID-19 pandemic, affecting nearly half of all those who responded to the survey. These results underline the need to assess support for professional wellbeing of radiologists in Spain. No correlations were identified between burnout and gender, age, number of calls, years in the job, annual income, teaching, marital status, number of children, or type of contract.

[Development of severity and mortality prediction models for covid-19 patients at emergency department including the chest x-ray]. / Elaboración de modelos predictivos de la gravedad y la mortalidad en pacientes con COVID-19 que acuden al servicio de urgencias, incluida la radiografía torácica.

Objectives: To develop prognosis prediction models for COVID-19 patients attending an emergency department (ED) based on initial chest X-ray (CXR), demographics, clinical and laboratory parameters. Methods: All symptomatic confirmed COVID-19 patients admitted to our hospital ED between February 24th and April 24th 2020 were recruited. CXR features, clinical and laboratory variables and CXR abnormality indices extracted by a convolutional neural network (CNN) diagnostic tool were considered potential predictors on this first visit. The most serious individual outcome defined the three severity level: 0) home discharge or hospitalization ≤ 3 days, 1) hospital stay >3 days and 2) intensive care requirement or death. Severity and in-hospital mortality multivariable prediction models were developed and internally validated. The Youden index was used for the optimal threshold selection of the classification model. Results: A total of 440 patients were enrolled (median 64 years; 55.9% male); 13.6% patients were discharged, 64% hospitalized, 6.6% required intensive care and 15.7% died. The severity prediction model included oxygen saturation/inspired oxygen fraction (SatO2/FiO2), age, C-reactive protein (CRP), lymphocyte count, extent score of lung involvement on CXR (ExtScoreCXR), lactate dehydrogenase (LDH), D-dimer level and platelets count, with AUC-ROC = 0.94 and AUC-PRC = 0.88. The mortality prediction model included age, SatO2/FiO2, CRP, LDH, CXR extent score, lymphocyte count and D-dimer level, with AUC-ROC = 0.97 and AUC-PRC = 0.78. The addition of CXR CNN-based indices did not improve significantly the predictive metrics. Conclusion: The developed and internally validated severity and mortality prediction models could be useful as triage tools in ED for patients with COVID-19 or other virus infections with similar behaviour.

[Prevalence of burnout syndrome during the COVID-19 pandemic and associated factors]. / Prevalencia y factores de desgaste profesional en radiólogos durante la pandemia COVID-19.

Background: The coronavirus 2019 (COVID-19) epidemic spread throughout the world from the beginning of 2020, increasing healthcare professionals' workloads and levels of physical and emotional stress. Aims: To determine the prevalence of burnout syndrome in Spanish radiologists during the COVID-19 pandemic and the factors associated with the development of this syndrome, and to compare these findings with those obtained before the pandemic. Methods: This observation study took place between April 2020 and August 2020 (during the pandemic) through an online survey. A total of 150 responses were obtained. Demographic and work-related information was compiled. Burnout syndrome was measured with the Maslach Burnout Inventory Human Services Survey (MBI-HSS). The prevalence and characteristics of burnout syndrome obtained in this survey were compared with those of the same survey done in 2019. We performed a statistical analysis to identify possible risk factors and protective factors associated with this syndrome and to determine the homogeneity of the two samples. Results: The prevalence of burnout syndrome increased during the COVID-19 pandemic (49.3% vs. 33.6%, p = 0.002). No risk factors or protective factors that were valid both before and after the pandemic were identified. No correlations were identified between sociodemographic or work-related characteristics and burnout syndrome. Conclusion: This study demonstrates that burnout syndrome increased significantly in radiologists during the COVID-19 pandemic, affecting nearly half of all those who responded to the survey. These results underline the need to assess support for professional wellbeing of radiologists in Spain. No correlations were identified between burnout and gender, age, number of calls, years in the job, annual income, teaching, marital status, number of children, or type of contract.

Differences in multi-echo chemical shift encoded MRI proton density fat fraction estimation based on multifrequency fat peaks selection in non-alcoholic fatty liver disease patients.

AIM: To compare the performance of multi-echo chemical-shift-encoded (MECSE) magnetic resonance imaging (MRI) proton density fat fraction (PDFF) estimation, considering three different fat frequency peak combinations, for the quantification of steatosis in patients with non-alcoholic fatty liver disease (NAFLD). MATERIALS AND METHODS: The present study was a prospective cross-sectional research of 121 patients with metabolic syndrome and evidence of hepatic steatosis on ultrasound, who underwent a 3 T MRI examination. All patients were studied with a multifrequency MECSE sequence. The PDFF was calculated using six peaks (MECSEp123456), three peaks (MECSEp456), and a single peak (MECSEp5) model. The two simpler fat peak models were compared to the six peaks model, which was considered the reference standard. Linearity was evaluated using linear regression while agreement was described using Bland-Altman analysis. RESULTS: The mean age was 47 (±9) years and BMI was 29.9 (±2.9) kg/m2. Steatosis distribution was 15%/31%/54% (S1/S2/S3, respectively). Compared to MECSEp123456, both models provided linear PDFF measurements (R2= 0.99 and 0.97, MECSEp456 and MECSEp5 respectively). Regression slope (0.92; p<0.001) and mean Bland-Altman bias (-1.5%; 95% limits of agreement: -3.19%, 0.22%) indicated minimal underestimation by using PDFF-MECSEp456. Nonetheless, mean differences in PDFF estimations varied from -1.5% (MECSEp456,p=0.006) to -2.2% (MECSEp5,p<0.001) when compared to full six fat frequencies model. CONCLUSION: Although simpler spectral fat MECSE analysis shows a linear relationship with the standard six peaks model, their variation in estimated PDFF values introduces a low but clinically significant bias in fat quantification and steatosis grading in NAFLD patients.

Magnetic Resonance imaging analysis of liver fibrosis and inflammation: overwhelming gray zones restrict clinical use.

Magnetic resonance (MR) identification and grading of subjects with liver fibrosis and inflammation represents a clinical challenge. MR elastography plays a well-defined role in fibrosis estimation, but its use is not widely available in clinical settings. Given that liver MR is becoming the reference standard for fat and iron quantitation, there is a need to clarify whether there is any role for MR imaging in the concomitant evaluation of fibrosis and inflammation in this setting. This review summarizes the diagnostic estimations of different MR imaging parameters obtained from conventional non-contrast-enhanced multiple b values diffusion-weighted acquisitions, variable flip angles T1 relaxation maps and STIR images. Although some derived parameters have shown a significant correlation to histological scores, a small magnitude of effect with wide overlap across severity grades is the rule. Contrary to fat and iron quantification, the low precision and reproducibility of MR imaging metrics limits its clinical relevance in fibrosis and inflammation assessment. In a sequential clinical approach combining different methodologies, MR imaging has no applicability for ruling-out and low accuracy for ruling-in advanced fibrosis. Thereby, MR elastography remains as the only image method with high diagnostic accuracy for the detection of advanced fibrosis. Until date, inflammation remains in a gray zone where biopsy cannot be replaced, and further investigations are needed. The present review offers an in-depth discuss of the MR imaging diagnostic performance for the evaluation of liver fibrosis and inflammation, highlighting the need for scientific improvements.

Critical review of HCC imaging in the multidisciplinary setting: treatment allocation and evaluation of response.

Imaging has not only an established role in screening and diagnosis of hepatocellular carcinoma (HCC) in patients with chronic liver inflammatory diseases, but also a crucial importance for patient stratification and treatment allocation, as well as for assessing treatment response. In the setting of increasing therapeutic options for HCC, the Barcelona Clinic Liver Cancer (BCLC) system still remains the most appropriate way to select candidate cohorts for best treatments. This classification takes into account the imaging information on tumor burden and extension, liver function, and cancer-related symptoms, stratifying patients in five risk categories (Stages 0, A, B, C and D) associated with different treatment options. Still now, there are no clear roles for biomarkers use in treatment allocation. The increasing use of locoregional non-surgical therapies in the different stages is highly dependent on reliable evaluation of treatment response, in particular when they are used with curative intention or for downstaging at liver transplantation re-assessment. Moreover, objective response (OR) has emerged as an important imaging biomarker, providing information on tumor biology, which can contribute for further prognostic assessment. Current guidelines for OR assessment recommend only the measurement of viable tumor according to mRECIST criteria, with further classification into complete response, partial response, stable disease or progressive disease. Either computed tomography (CT) or magnetic resonance (MR) imaging can be used for this purpose, and the Liver Imaging Reporting and Data System (LI-RADS) committee has recently provided some guidance for reporting after locoregional therapies. Nevertheless, imaging pitfalls resulting from treatment-related changes can impact with the correct evaluation of treatment response, especially after transarterial radioembolization (TARE). Volume criteria and emerging imaging techniques might also contribute for a better refinement in the assessment of treatment response and monitoring. As the role of imaging deeply expands in the multidisciplinary assessment of HCC, our main objective in this review is to discuss state-of-the-art decision-making aspects for treatment allocation and provide guidance for treatment response evaluation.

Quantifying steatosis in the liver and pancreas with MRI in patient with chronic liver disease. / Cuantificación por resonancia magnética de esteatosis hepática y pancreática en hepatopatía crónica.

AIM: To compare pancreatic and hepatic steatosis quantified by proton density fat fraction (PDFF) on magnetic resonance imaging (MRI) in patients with chronic liver disease. MATERIAL AND METHODS: This cross-sectional study included 46 adult patients who underwent liver biopsy for chronic viral hepatitis (n=19) or other chronic non-alcoholic liver diseases (NALD) (n=27). Liver biopsy was used as the gold standard for diagnosing and grading hepatic steatosis. All patients underwent clinical evaluation and MRI with a multi-echo chemical shift-encoded (MECSE) gradient-echo sequence for liver and pancreas PDFF quantification. We used Spearman's correlation coefficient to determine the degree of association between hepatic PDFF and steatosis grade, and between pancreatic PDFF and steatosis grade and hepatic PDFF. To compare the chronic viral hepatitis group and the NALD group, we used t-tests for continuous or ordinal variables and chi-square tests for categorical variables. RESULTS: Hepatic PDFF measurements correlated with steatosis grades (RS=0.875, p<0.001). Pancreatic PDFF correlated with hepatic steatosis grades (RS=0.573, p<0.001) and hepatic PDFF measurements (RS=0.536, p<0.001). In the subgroup of patients with chronic NALD, the correlations remained significant between pancreatic PDFF and hepatic PDFF (RS=0.632, p<0.001) and between pancreatic PDFF and liver steatosis (RS=0.608, p<0.001); however, in the subgroup of patients with viral hepatitis these correlations were no longer significant. CONCLUSION: Pancreatic fat deposition correlates with hepatic steatosis in patients with chronic NALD, but not in those with chronic viral hepatitis.

Hepatic and pancreatic fat as imaging biomarkers of metabolic syndrome. / Valoración de la grasa hepática y pancreática como biomarcadores de imagen en el síndrome metabólico.

OBJECTIVE: To objectively evaluate hepatic and pancreatic involvement in metabolic syndrome through magnetic resonance imaging (MRI) biomarkers. MATERIAL AND METHODS: From an initial retrospective sample of 407 patients diagnosed with metabolic syndrome studied by MRI in a single center during a 2-year period, 154 were excluded because of a lack of clinical and/or laboratory data, pancreatic abnormalities, or inadequate quality of MRI studies. To measure hepatic and pancreatic fat, we used chemical shift imaging (in-phase and out-of-phase), measuring the fat fraction (%) in regions of interest in the pancreas and liver. Associations between the fat fraction and selected clinical and laboratory variables were assessed with beta regression models. RESULTS: In the end, 253 patients were included. The hepatic fat fraction was 4.9% and the pancreatic fat fraction was 7.9%. We found no significant associations between the hepatic fat fraction and any of the clinical or laboratory variables. However, the pancreatic fat fraction was positively associated with age (OR=1.025, p<0.001) and baseline glucose (OR=1.005, p<0.001). Patients with diabetes had higher values of pancreatic fat fraction (OR=2.64, p=0.038). Pancreatic fat fraction and hepatic fat fraction were positively associated (OR=69.44, p<0.001). CONCLUSIONS: Pancreatic steatosis can be considered a marker of metabolic syndrome and diabetes. Quantitative MRI enables the diagnosis and grading of fatty pancreas through simple chemical shift techniques.

Re-evaluating the significance of the dive response during voluntary surface apneas in the bottlenose dolphin, Tursiops truncatus.

The dive response is well documented for marine mammals, and includes a significant reduction in heart rate (fH) during submersion as compared while breathing at the surface. In the current study we assessed the influence of the Respiratory Sinus Arrhythmia (RSA) while estimating the resting fH while breathing. Using transthoracic echocardiography we measured fH, and stroke volume (SV) during voluntary surface apneas at rest up to 255 s, and during recovery from apnea in 11 adult bottlenose dolphins (Tursiops truncatus, 9 males and 2 females, body mass range: 140-235 kg). The dolphins exhibited a significant post-respiratory tachycardia and increased SV. Therefore, only data after this RSA had stabilized were used for analysis and comparison. The average (±s.d.) fH, SV, and cardiac output (CO) after spontaneous breaths while resting at the surface were 44 ± 6 beats min-1, 179 ± 31 ml, and 7909 ± 1814 l min-1, respectively. During the apnea the fH, SV, and CO decreased proportionally with the breath-hold duration, and after 255 s they, respectively, had decreased by an average of 18%, 1-21%, and 12-37%. During recovery, the fH, SV, and CO rapidly increased by as much as 117%, 34%, and 190%, respectively. Next, fH, SV and CO rapidly decreased to resting values between 90-110 s following the surface apnea. These data highlight the necessity to define how the resting fH is estimated at the surface, and separating it from the RSA associated with each breath to evaluate the significance of cardiorespiratory matching during diving.

Quantitative structural analysis of trabecular alveolar bone in the mandible by multidetector computed tomography: differences according to tooth presence and type. / Análisis estructural cuantitativo del hueso alveolar trabecular de la mandíbula en tomografía computarizada multidetector: diferencias por tipo y estado dentario.

BACKGROUND AND OBJECTIVE: There is a lack of quantitative measures of the quality of alveolar trabecular bone, an important factor in implantology. This study aimed to develop a method of objectively assessing the quality of trabecular bone by means of image processing and structural analysis of multidetector computed tomography images and to establish differences between tooth types and tooth presence/absence. MATERIALS AND METHODS: We analyzed 20 patients who underwent multidetector computed tomography to evaluate mandibular bone and tooth positioning. Image analysis included automatic segmentation of the mandible, obtainment of sections perpendicular to the dental arch, and structural analysis of the trabecular bone in each section. We calculated the ratio between the volume of bone and the total volume of the section, the thickness, the trabecular number, and the mean attenuation in Hounsfield units. We analyzed the differences among different tooth types (incisors, canines, premolars, and molars) and between present and absent teeth. RESULTS: We found statistically significant differences between different tooth types and between sections in which teeth were present or absent. Incisors had a greater ratio of trabecular bone; the ratio of trabecular bone progressively decreased from the incisors to the canines, premolars, and molars. The ratio of trabecular bone was greater in sections in which teeth were absent than in those in which teeth were present. CONCLUSIONS: The method allows to quantify the structural properties of alveolar bone from multidetector computed tomography images. Our results provide an objective picture of the bone substrate that can be useful for planning and following up dental implant procedures.

Insulin resistance and NAFLD: Relationship with intrahepatic iron and serum TNF-α using 1H MR spectroscopy and MRI.

AIM: The association of non-alcoholic fatty liver disease (NAFLD) with insulin resistance (IR) is well established, yet little is known of their possible relationship with intrahepatic iron and serum tumour necrosis factor (TNF)-α concentrations in adults without diabetes. Thus, this study looked at the relationship of intrahepatic iron and serum TNF-α with intrahepatic triglycerides and IR in non-diabetic adults. METHODS: In this cross-sectional study of 104 healthy non-diabetic Caucasians, a quantitative magnetic resonance (MR) imaging T2 gradient-echo technique was used to measure hepatic iron, with 1H-MR spectroscopy used to measure hepatic triglycerides. HOMA-IR was calculated to determine IR. RESULTS: The prevalence of hepatic iron overload (HIOL) was 26.6% in individuals with NAFLD vs. 0% in those without. IR was present in 87.5% of subjects with both NAFLD and HIOL, in 45.4% of those with NAFLD but not HIOL, and in 4.5% of those with neither. HOMA-IR was positively correlated with hepatic triglycerides (r = 0.56, P < 0.001) and hepatic iron (r = 0.52, P < 0.001), whereas serum TNF-α concentrations correlated with intrahepatic triglyceride levels (r = 0.28, P < 0.04), but not with intrahepatic iron. Hepatic triglycerides, serum TNF-α and age were the only significant determinants of IR in regression analyses. CONCLUSION: IR is closely associated with intrahepatic triglycerides and, to a lesser extent, intrahepatic iron, with some interplay between them. High serum TNF-α concentrations may contribute to the association between NAFLD and IR, while increased hepatic triglycerides appear to be a determinant of the development of HIOL in non-diabetic subjects without haemochromatosis.

Significance of the impact of motion compensation on the variability of PET image features.

In lung cancer, quantification by positron emission tomography/computed tomography (PET/CT) imaging presents challenges due to respiratory movement. Our primary aim was to study the impact of motion compensation implied by retrospectively gated (4D)-PET/CT on the variability of PET quantitative parameters. Its significance was evaluated by comparison with the variability due to (i) the voxel size in image reconstruction and (ii) the voxel size in image post-resampling. The method employed for feature extraction was chosen based on the analysis of (i) the effect of discretization of the standardized uptake value (SUV) on complementarity between texture features (TF) and conventional indices, (ii) the impact of the segmentation method on the variability of image features, and (iii) the variability of image features across the time-frame of 4D-PET. Thirty-one PET-features were involved. Three SUV discretization methods were applied: a constant width (SUV resolution) of the resampling bin (method RW), a constant number of bins (method RN) and RN on the image obtained after histogram equalization (method EqRN). The segmentation approaches evaluated were 40[Formula: see text] of SUVmax and the contrast oriented algorithm (COA). Parameters derived from 4D-PET images were compared with values derived from the PET image obtained for (i) the static protocol used in our clinical routine (3D) and (ii) the 3D image post-resampled to the voxel size of the 4D image and PET image derived after modifying the reconstruction of the 3D image to comprise the voxel size of the 4D image. Results showed that TF complementarity with conventional indices was sensitive to the SUV discretization method. In the comparison of COA and 40[Formula: see text] contours, despite the values not being interchangeable, all image features showed strong linear correlations (r > 0.91, [Formula: see text]). Across the time-frames of 4D-PET, all image features followed a normal distribution in most patients. For our patient cohort, the compensation of tumor motion did not have a significant impact on the quantitative PET parameters. The variability of PET parameters due to voxel size in image reconstruction was more significant than variability due to voxel size in image post-resampling. In conclusion, most of the parameters (apart from the contrast of neighborhood matrix) were robust to the motion compensation implied by 4D-PET/CT. The impact on parameter variability due to the voxel size in image reconstruction and in image post-resampling could not be assumed to be equivalent.

Tissue iron quantification in chronic liver diseases using MRI shows a relationship between iron accumulation in liver, spleen, and bone marrow.

AIM: To investigate iron loading within the liver, pancreas, spleen, and bone marrow using magnetic resonance imaging (MRI) transverse relaxation rate (R2*), in patients with diffuse liver diseases; to evaluate the relationships between iron accumulation in these tissue compartments; and to assess the association between tissue iron overload and the pattern of hepatic cellular iron distribution (hepatocytes versus Kupffer cells). MATERIAL AND METHODS: Fifty-six patients with diffuse liver diseases had MRI-derived R2* values, using a multi-echo chemical-shift encoded MRI sequence, of the liver, pancreas, spleen, and vertebral bone marrow. All patients had liver biopsy samples scored for hepatic iron grading (0-4) and iron cellular distribution (within hepatocytes only or within both hepatocytes and Kupffer cells). RESULTS: Liver R2* increased with histological iron grade (RS=0.58, p<0.001) and correlated with spleen (RS=0.71, p<0.001) and bone marrow R2* (RS=0.66, p<0.001), but not with pancreatic R2* (RS=0.22, p=0.096). Splenic and bone marrow R2* values were also correlated (RS=0.72, p<0.001). Patients with iron inside Kupffer cells had the highest R2* in liver, spleen and bone marrow. CONCLUSIONS: Patients with chronic diffuse liver diseases have concomitant hepatic, splenic, and bone marrow iron loading. The highest hepatic iron scores and iron inside Kupffer cells were associated with the highest splenic and bone marrow deposits, suggesting systemic iron accumulation in the mononuclear phagocytic system.

Imaging biomarkers in liver fibrosis. / Cuantificación de la fibrosis hepática mediante biomarcadores de imagen.

There is a need for early identification of patients with chronic liver diseases due to their increasing prevalence and morbidity-mortality. The degree of liver fibrosis determines the prognosis and therapeutic options in this population. Liver biopsy represents the reference standard for fibrosis staging. However, given its limitations and complications, different non-invasive methods have been developed recently for the in vivo quantification of fibrosis. Due to their precision and reliability, biomarkers' measurements derived from Ultrasound and Magnetic Resonance stand out. This article reviews the different acquisition techniques and image processing methods currently used in the evaluation of liver fibrosis, focusing on their diagnostic performance, applicability and clinical value. In order to properly interpret their results in the appropriate clinical context, it seems necessary to understand the techniques and their quality parameters, the standardization and validation of the measurement units and the quality control of the methodological problems.

Noninvasive Liver Assessment in Adult Patients With Fontan Circulation Using Acoustic Radiation Force Impulse Elastography and Hepatic Magnetic Resonance Imaging.

BACKGROUND: Patients who have undergone the Fontan procedure are at risk of developing hepatic dysfunction. However, broad recommendations regarding liver monitoring are limited. The purpose of this study was to characterize the frequency of liver disease in adult Fontan patients using multimodality imaging (hepatic magnetic resonance imaging [MRI], acoustic radiation force impulse [ARFI] elastography, or hepatic ultrasound). METHODS: In a prospective cross-sectional analysis of adult patients palliated with a Fontan procedure, hepatic MRI, ARFI, and hepatic ultrasound were used to assess for liver disease. The protocol compared (1) varying prevalence of liver disease based on each imaging technique, (2) agreement between different techniques, and (3) association between noninvasive imaging diagnosis of liver disease and clinical variables, including specific liver disease biomarkers. RESULTS: Thirty-seven patients were enrolled. The ARFI results showed high wave propagation velocity in 35 patients (94.6%). All patients had some abnormality in the hepatic MRI. Specifically, 8 patients (21.6%) showed signs of chronic liver disease, 10 patients (27%) had significant liver fibrosis, and 27 patients (73%) had congestion. No correlation was found between liver stiffness measured as propagation velocity and hepatic MRI findings. Only 7 patients had an abnormal hepatic ultrasound study. CONCLUSIONS: There is an inherent liver injury in adult Fontan patients. Signs of liver disease were observed in most patients by both hepatic MRI and ARFI elastography but not by ultrasound imaging. Increased liver stiffness did not identify specific disease patterns from MRI, supporting the need for multimodality imaging to characterize liver disease in Fontan patients.

Retention of gadolinium compounds used in magnetic resonance imaging: a critical review and the recommendations of regulatory agencies. / Retención de compuestos de gadolinio usados en resonancia magnética: revisión crítica y recomendaciones de las agencias regulatorias.

The Spanish Agency for Drugs and Healthcare Products (AEMPS), based on the recommendations of the European Committee for Risk Assessment in Pharmacovigilance, established on 13 March 2017 that linear gadolinium-based MR contrast media, such as MultiHance, Omniscan, Magnevist (currently not marketed) and Optimark (no longer marketed in Spain), the clinical benefits do not outweigh the potential risks derived from their use. AEMPS recommends to suspend its marketing for general use based on the retention of these compounds in the brain. On the other hand, the AEMPS justifies the maintenance of Primovist and MultiHance for liver studies, and Magnevist of intra-articular administration (not commercialized in Spain), and justified the almost exclusive use of macrocyclic structure contrasts (Gadovist, ProHance and Dotarem). However, this retention is known to be different for each of the contrast media. All existing gadolinium contrasts agents have a distribution phase with tissue retention, due to a very slow exchange, in the interstitium of bone, skin, kidney, brain and other organs. The existence of histological effects or clinical symptoms associated with the accumulation of these trace amounts of gadolinium has not been demonstrated. The major toxicological concern with these contrast agents is related to nephrogenic systemic fibrosis (NSF). Since the safety profiles are mainly related to the interstitial retention space in the tissues, it does not seem justified to actually exclude contrast media that do not have cases related to the NSF. Based on all of this, we disagree with the latest AEMPS recommendation suggesting the marketing stoppage of linear agents without considering the individual retention profiles. This recommendation is not based neither on the data nor existing knowledge about the retention, relaxivity and clinical efficiency of the Gd compounds. It is therefore necessary to carry out prospective studies on the histological and clinical relevance of these organic Gd deposits.