Hydatid liver disease with portal vein invasion, cavernous transformation and portal biliopathy.

Hydatid disease is a zoonotic parasitic disease, most commonly affecting the liver, lungs and nervous system. Portal vein involvement by hydatid cyst disease is very rare with only few cases published to our knowledge. We describe a case involving a 53-year-old woman with portal vein invasion, cavernous transformation and portal biliopathy.

CheXmask: a large-scale dataset of anatomical segmentation masks for multi-center chest x-ray images.

The development of successful artificial intelligence models for chest X-ray analysis relies on large, diverse datasets with high-quality annotations. While several databases of chest X-ray images have been released, most include disease diagnosis labels but lack detailed pixel-level anatomical segmentation labels. To address this gap, we introduce an extensive chest X-ray multi-center segmentation dataset with uniform and fine-grain anatomical annotations for images coming from five well-known publicly available databases: ChestX-ray8, CheXpert, MIMIC-CXR-JPG, Padchest, and VinDr-CXR, resulting in 657,566 segmentation masks. Our methodology utilizes the HybridGNet model to ensure consistent and high-quality segmentations across all datasets. Rigorous validation, including expert physician evaluation and automatic quality control, was conducted to validate the resulting masks. Additionally, we provide individualized quality indices per mask and an overall quality estimation per dataset. This dataset serves as a valuable resource for the broader scientific community, streamlining the development and assessment of innovative methodologies in chest X-ray analysis.

Artificial Intelligence Assistance for the Measurement of Full Alignment Parameters in Whole-Spine Lateral Radiographs.

BACKGROUND: Measuring spinal alignment with radiological parameters is essential in patients with spinal conditions likely to be treated surgically. These evaluations are not usually included in the radiological report. As a result, spinal surgeons commonly perform the measurement, which is time-consuming and subject to errors. We aim to develop a fully automated artificial intelligence (AI) tool to assist in measuring alignment parameters in whole-spine lateral radiograph (WSL X-rays). METHODS: We developed a tool called Vertebrai that automatically calculates the global spinal parameters (GSPs): Pelvic incidence, sacral slope, pelvic tilt, L1-L4 angle, L4-S1 lumbo-pelvic angle, T1 pelvic angle, sagittal vertical axis, cervical lordosis, C1-C2 lordosis, lumbar lordosis, mid-thoracic kyphosis, proximal thoracic kyphosis, global thoracic kyphosis, T1 slope, C2-C7 plummet, spino-sacral angle, C7 tilt, global tilt, spinopelvic tilt, and hip odontoid axis. We assessed human-AI interaction instead of AI performance alone. We compared the time to measure GSP and inter-rater agreement with and without AI assistance. Two institutional datasets were created with 2267 multilabel images for classification and 784 WSL X-rays with reference standard landmark labeled by spinal surgeons. RESULTS: Vertebrai significantly reduced the measurement time comparing spine surgeons with AI assistance and the AI algorithm alone, without human intervention (3 minutes vs. 0.26 minutes; P < 0.05). Vertebrai achieved an average accuracy of 83% in detecting abnormal alignment values, with the sacral slope parameter exhibiting the lowest accuracy at 61.5% and spinopelvic tilt demonstrating the highest accuracy at 100%. Intraclass correlation analysis revealed a high level of correlation and consistency in the global alignment parameters. CONCLUSIONS: Vertebrai's measurements can accurately detect alignment parameters, making it a promising tool for measuring GSP automatically.

Prognostic role of magnetic resonance imaging of the abdomen with intravenous contrast and magnetic resonance cholangiopancreatography in primary sclerosing cholangitis.

Objective: To evaluate the usefulness of Anali scores, determined by magnetic resonance imaging, for predicting the prognosis of primary sclerosing cholangitis (PSC) and to analyze interobserver variability, as well as to assess the impact of periportal edema and heterogeneous signal intensity on diffusion-weighted imaging of the liver. Materials and Methods: This was a retrospective cohort study of 29 patients with PSC and baseline magnetic resonance imaging. Anali scores, without gadolinium (0-5 points) and with gadolinium (0-2 points), were calculated by two radiologists. Clinical end-points included liver transplantation, cirrhotic decompensation, and death. We calculated intraclass correlation coefficients (ICCs) for interobserver agreement on the Anali scores, performed Kaplan-Meier survival analysis comparing event-free survival among the score strata, and calculated the areas under receiver operating characteristic curves to determine sensitivity and specificity. Results: Among the patients with a clinical event, the median Anali score was 4 (interquartile range [IQR], 2-5) without gadolinium and 2 (IQR, 1-2) with gadolinium, compared with 1 (IQR, 1.0-2.5) and 1 (IQR, 0.25-1.0), respectively, among those without a clinical event. The ICC was 0.79 (95% confidence interval: 0.57-0.91) for the Anali score with gadolinium and 0.99 (95% confidence interval: 0.98-0.99) for the Anali score without gadolinium. Periportal edema and heterogeneous signal intensity in the liver on diffusion-weighted imaging showed no statistical impact on clinical events (p = 0.65 and p = 0.5, respectively). Conclusion: Anali scores correlate with clinical events in PSC, with a high level of interobserver agreement.

Objetivo: Avaliar a utilidade dos escores Anali determinados por ressonância magnética para prever o prognóstico da colangite esclerosante primária (CEP), analisar a variabilidade interobservador e avaliar o impacto do edema periportal e do sinal heterogêneo do fígado em imagens ponderadas por difusão. Materiais e Métodos: Estudo retrospectivo de coorte de 29 pacientes com CEP e ressonância magnética de base. Os escores Anali sem gadolínio (0 a 5 pontos) e com gadolínio (0 a 2 pontos) foram calculados por dois radiologistas. Os desfechos clínicos incluíram transplante de fígado, descompensação cirrótica ou morte. Foram realizados coeficiente de correlação intraclasse (CCI) para a concordância interobservador com relação ao escore Anali, análise de sobrevivência de Kaplan-Meier comparando o tempo livre de eventos de acordo com o escore, e área sob a curva característica de operação do receptor para sensibilidade e especificidade. Resultados: Nos pacientes com evento clínico, a mediana do escore Anali sem gadolínio foi 4 (intervalo interquartil [IIQ]: 2­5) e com gadolínio foi 2 (IIQ: 1­2), enquanto nos pacientes sem evento clínico o escore sem gadolínio foi 1 (IIQ:1­2,5) e com gadolínio foi 1 (IIQ: 0,25­1). A concordância interobservador com gadolínio foi CCI = 0,79 (intervalo de confiança 95%: 0,57­0,91) e sem gadolínio foi CCI = 0,99 (intervalo de confiança 95%: 0,98-0,99). O edema periportal (p = 0,65) e o sinal heterogêneo do fígado nas imagens ponderadas por difusão (p = 0,5) não apresentaram impacto nos eventos clínicos. Conclusão: Os escores Anali se correlacionam com eventos clínicos na CEP, com alto grau de concordância interobservador.

Measuring the Delay in the Referral of Unstable Vertebral Metastasis to the Spine Surgeon: A Retrospective Study in a Latin American Institution.

Background: The delay in the referral of patients with potential surgical vertebral metastasis (VM) to the spine surgeon is strongly associated with a worse outcome. The spinal instability neoplastic score (SINS) allows for determining the risk of instability of a spine segment with VM; however, it is almost exclusively used by specialists or residents in neurosurgery or orthopedics. The objective of this work is to report the delay in surgical consultation of patients with potentially unstable and unstable VM (SINS >6) at our center. Material: We performed a 5-year single-center retrospective analysis of patients with spine metastasis on computed tomography (CT). Patients were divided into Group 1 (G1), potentially unstable VM (SINS 7-12), and Group 2 (G2), unstable VM (SINS 13-18). Time to surgical referral was calculated as the number of days between the report of the VM in the CT and the first clinical assessment of a spinal surgeon on the medical records. Results: We analyzed 220 CT scans, and 98 met the selection criteria. Group 1 had 85 patients (86.7%) and Group 2 had 13 (13.3%). We observed a mean time to referral of 83.5 days in the entire cohort (std = 127.6); 87.6 days (std = 135.1) for G1, and 57.2 days (std = 53.8) for G2. The delay in referral showed no significant correlation with the SINS score. Conclusion: We report a mean delay of 83.5 days in the surgical referral of VM (SINS >6, n = 98). Both groups showed cases of serious referral delay, with 25% of patients having the first surgical consultation more than three months after the CT study.

Radiomics and Machine Learning for prediction of two-year disease-specific mortality and KRAS mutation status in metastatic colorectal cancer.

PURPOSE: Colorectal cancer is usually accompanied by liver metastases. The prediction of patient evolution is essential for the choice of the appropriate therapy. The aim of this study is to develop and evaluate machine learning models to predict KRAS gene mutations and 2-year disease-specific mortality from medical images. METHODS: Clinical and follow-up information was collected from patients with metastatic colorectal cancer who had undergone computed tomography prior to liver resection. The dominant liver lesion was segmented in each scan and radiomic features were extracted from the volumes of interest. The 65% of the cases were employed to perform feature selection and to train machine learning algorithms through cross-validation. The best performing models were assembled and evaluated in the remaining cases of the cohort. RESULTS: For the mortality model development, 101 cases were used as training set (64 alive, 37 deceased) and 35 as test set (22 alive, 13 deceased); while for KRAS mutation models, 55 cases were used for training (31 wild-type, 24 mutated) and 30 for testing (17 wild-type, 13 mutated). The ensemble of top performing models resulted in an area under the receiver operating characteristic curve of 0.878 for mortality and 0.905 for KRAS prediction. CONCLUSIONS: Predicting the prognosis of patients with metastatic colorectal cancer is useful for making timely decisions about the best treatment options. This study presents a noninvasive method based on quantitative analysis of baseline images to identify factors influencing patient outcomes, with the aim of incorporating these tools as support systems.

User Satisfaction with an AI System for Chest X-Ray Analysis Implemented in a Hospital's Emergency Setting.

The acceptance of artificial intelligence (AI) systems by health professionals is crucial to obtain a positive impact on the diagnosis pathway. We evaluated user satisfaction with an AI system for the automated detection of findings in chest x-rays, after five months of use at the Emergency Department. We collected quantitative and qualitative data to analyze the main aspects of user satisfaction, following the Technology Acceptance Model. We selected the intended users of the system as study participants: radiology residents and emergency physicians. We found that both groups of users shared a high satisfaction with the system's ease of use, while their perception of output quality (i.e., diagnostic performance) differed notably. The perceived usefulness of the application yielded positive evaluations, focusing on its utility to confirm that no findings were omitted, and also presenting distinct patterns across the two groups of users. Our results highlight the importance of clearly differentiating the intended users of AI applications in clinical workflows, to enable the design of specific modifications that better suit their particular needs. This study confirmed that measuring user acceptance and recognizing the perception that professionals have of the AI system after daily use can provide important insights for future implementations.

Follicular Cholecystitis Mimicking Xanthogranulomatous Cholecystitis and Malignancy: A Case Report.

Chronic follicular cholecystitis (CFC) is a rare pathology characterized by prominent lymphoid follicles in the lamina propria distributed throughout the gallbladder wall. It has also been mentioned in the literature as lymphoid hyperplasia and pseudolymphoma. CFC represents less than 2% of cholecystectomies. Its etiopathology is mostly unknown. Most reports are based on histopathological findings, with little or no imaging analysis. We describe a case involving a 66-year-old man radiologically diagnosed as xanthogranulomatous cholecystitis (XGC) versus malignancy, revealing CFC with surrounding inflammatory changes in the cholecystectomy specimen.

Inteligencia artificial. Aplicación en las imágenes cardiovasculares y la prevención cardiovascular / Artificial Intelligence in Cardiovascular Imaging and Cardiovascular Prevention

RESUMEN La inteligencia artificial (IA) está basada en programas computacionales que pueden imitar el pensamiento humano y automatizar algunos procesos. En el ámbito médico se está estudiando hace más de 50 años, pero en los últimos años el crecimiento ha sido exponencial. El campo de las imágenes cardiovasculares es particularmente atractivo para aplicarla, dado que, guiadas por IA, personas no expertas pueden adquirir imágenes completas, automatizar procesos y mediciones, orientar diagnósticos, detectar hallazgos no visibles al ojo humano, realizar diagnósticos oportunistas de afecciones no buscadas en el estudio índice pero evaluables a través de las imágenes disponibles, o identificar patrones de asociación dentro de una gran cantidad de datos como fuente de generación de hipótesis. En el campo de la prevención cardiovascular, la IA se ha aplicado en diferentes escenarios con fines diagnósticos, pronósticos y terapéuticos en el manejo de algunos factores de riesgo cardiovascular, como las dislipidemias o la hipertensión arterial. Si bien existen limitaciones con el uso de la IA tales como el costo, la accesibilidad y la compatibilidad de los programas, la validez externa de los resultados en determinadas poblaciones, o algunos aspectos éticos-legales (privacidad de los datos), esta tecnología está en crecimiento vertiginoso y posiblemente revolucione la práctica médica actual.

ABSTRACT Artificial intelligence (AI) is based on computer programs that imitate human thinking and automate certain processes. Artificial intelligence has been studied in the medical field for over 50 years, but in recent years, its growth has been exponential. The field of cardiovascular imaging is particularly attractive since AI can guide non-experts in image acquisition, automate processes and measurements, guide diagnoses, detect findings not visible to the human eye, make opportunistic diagnoses of unexpected conditions in the index test, or identify patterns of association within a large amount of data as a source of hypothesis generation. In the field of cardiovascular prevention, AI has been used for diagnostic, prognostic, and therapeutic purposes in managing cardiovascular risk factors such as dyslipidemia and hypertension. While there are limitations to the use of AI, such as cost, accessibility, compatibility of programs, external validity of results in certain populations, and ethical-legal aspects such as data privacy, this technology is rapidly growing and is likely to revolutionize current medical practice.

Prognostic role of magnetic resonance imaging of the abdomen with intravenous contrast and magnetic resonance cholangiopancreatography in primary sclerosing cholangitis / Papel prognóstico da ressonância magnética do abdome com contraste intravenoso e colangiopancreatografia por ressonância magnética na colangite esclerosante primária

Abstract Objective: To evaluate the usefulness of Anali scores, determined by magnetic resonance imaging, for predicting the prognosis of primary sclerosing cholangitis (PSC) and to analyze interobserver variability, as well as to assess the impact of periportal edema and heterogeneous signal intensity on diffusion-weighted imaging of the liver. Materials and Methods: This was a retrospective cohort study of 29 patients with PSC and baseline magnetic resonance imaging. Anali scores, without gadolinium (0-5 points) and with gadolinium (0-2 points), were calculated by two radiologists. Clinical end-points included liver transplantation, cirrhotic decompensation, and death. We calculated intraclass correlation coefficients (ICCs) for interobserver agreement on the Anali scores, performed Kaplan-Meier survival analysis comparing event-free survival among the score strata, and calculated the areas under receiver operating characteristic curves to determine sensitivity and specificity. Results: Among the patients with a clinical event, the median Anali score was 4 (interquartile range [IQR], 2-5) without gadolinium and 2 (IQR, 1-2) with gadolinium, compared with 1 (IQR, 1.0-2.5) and 1 (IQR, 0.25-1.0), respectively, among those without a clinical event. The ICC was 0.79 (95% confidence interval: 0.57-0.91) for the Anali score with gadolinium and 0.99 (95% confidence interval: 0.98-0.99) for the Anali score without gadolinium. Periportal edema and heterogeneous signal intensity in the liver on diffusion-weighted imaging showed no statistical impact on clinical events (p = 0.65 and p = 0.5, respectively). Conclusion: Anali scores correlate with clinical events in PSC, with a high level of interobserver agreement.

Resumo Objetivo: Avaliar a utilidade dos escores Anali determinados por ressonância magnética para prever o prognóstico da colangite esclerosante primária (CEP), analisar a variabilidade interobservador e avaliar o impacto do edema periportal e do sinal heterogêneo do fígado em imagens ponderadas por difusão. Materiais e Métodos: Estudo retrospectivo de coorte de 29 pacientes com CEP e ressonância magnética de base. Os escores Anali sem gadolínio (0 a 5 pontos) e com gadolínio (0 a 2 pontos) foram calculados por dois radiologistas. Os desfechos clínicos incluíram transplante de fígado, descompensação cirrótica ou morte. Foram realizados coeficiente de correlação intraclasse (CCI) para a concordância interobservador com relação ao escore Anali, análise de sobrevivência de Kaplan-Meier comparando o tempo livre de eventos de acordo com o escore, e área sob a curva característica de operação do receptor para sensibilidade e especificidade. Resultados: Nos pacientes com evento clínico, a mediana do escore Anali sem gadolínio foi 4 (intervalo interquartil [IIQ]: 2-5) e com gadolínio foi 2 (IIQ: 1-2), enquanto nos pacientes sem evento clínico o escore sem gadolínio foi 1 (IIQ:1-2,5) e com gadolínio foi 1 (IIQ: 0,25-1). A concordância interobservador com gadolínio foi CCI = 0,79 (intervalo de confiança 95%: 0,57-0,91) e sem gadolínio foi CCI = 0,99 (intervalo de confiança 95%: 0,98-0,99). O edema periportal (p = 0,65) e o sinal heterogêneo do fígado nas imagens ponderadas por difusão (p = 0,5) não apresentaram impacto nos eventos clínicos. Conclusão: Os escores Anali se correlacionam com eventos clínicos na CEP, com alto grau de concordância interobservador.

Tomografía computada y resonancia magnética en la patología de la vesícula biliar: más allá de la litiasis / Computed tomography and magnetic resonance in gallbladder patology: beyond lithiasis

Resumen La enfermedad de la vesícula biliar es una causa común de dolor abdominal. Si bien por lo general el dolor es secundario a la presencia de litiasis y colecistitis aguda, el espectro de la enfermedad es amplio e incluye anomalías congénitas, otros procesos inflamatorios y neoplasias. La tomografía computada (TC) y la resonancia magnética (RM) tienen un papel relevante en aquellos casos en los que la ecografía no es concluyente y en la planificación del tratamiento. Dentro de las anomalías congénitas, la forma en “gorro frigio” es la más frecuente. Los pólipos son en su mayoría lesiones benignas, siendo las características de malignidad un tamaño superior a 10 mm, solitario y sésil. La adenomiomatosis es reconocible por el engrosamiento de la pared vesicular y los componentes quísticos intramurales. Es importante reconocer el gas intramural e intraluminal en la colecistitis enfisematosa y los microabscesos y hemorragias intraluminales en la colecistitis gangrenosa debido a su alta morbilidad y mortalidad. La colecistitis xantogranulomatosa presenta nódulos intramurales que ocupan más del 60% del área de la pared engrosada y la conservación lineal del realce de la mucosa sin interrupción. El carcinoma vesicular se presenta como una lesión infiltrante que se extiende al hígado, un engrosamiento mural o una masa polipoide intraluminal.

Abstract Gallbladder disease is a common cause of abdominal pain. Although the pain is usually secondary to the presence of lithiasis and acute cholecystitis, the spectrum of the disease is broad and includes congenital anomalies, other inflammatory processes and neoplasms. Computed tomography (CT) and magnetic resonance (MRI) have a relevant role in those cases in which ultrasound is not conclusive and in treatment planning. Among the congenital anomalies, the “phrygian cap” shape is the most frequent. Polyps are mostly benign lesions, with the characteristics of malignancy being larger than 10 mm, solitary and sessile. Adenomyomatosis is recognizable by gallbladder wall thickening and intramural cystic components. It is important to recognize intramural and intraluminal gas in emphysematous cholecystitis and intraluminal microabscesses and hemorrhages in gangrenous cholecystitis because of its high morbidity and mortality. Xanthogranulomatous cholecystitis presents with intramural nodules occupying more than 60% of the thickened wall area and linear preservation of mucosal enhancement without interruption. Gallbladder carcinoma presents as an infiltrative lesion extending to the liver, a mural thickening or an intraluminal polypoid mass.

Anomalía de la unión biliopancreática: una entidad infrecuente en Occidente / Pancreaticobiliary maljunction: a rare entity in the West

Resumen La anomalía de la unión biliopancreática (AUBP) es una malformación congénita en la que los conductos pancreáticos y biliares se unen anatómicamente fuera de la pared duodenal. Debido a la excesiva longitud del canal común, la acción del esfínter no afecta la unión pancreatobiliar, lo que permite el reflujo del jugo pancreático hacia la vía biliar. Se asocia con quistes del colédoco y sus manifestaciones incluyen cáncer de la vía biliar, pancreatitis, coledocolitiasis y colangitis. Es una rara patología, especialmente en países occidentales. La colangiopancreatografía por resonancia magnética (CPRM) se ha convertido en el método más utilizado por no ser invasivo, teniendo en cuenta que la colangiopancreatografía retrógrada endoscópica (CPRE) se encuentra contraindicada en casos de pancreatitis aguda y colangitis, además del riesgo de pancreatitis posterior al procedimiento. La distancia entre la unión biliopancreática y la pared duodenal debe ser superior a 9 mm de longitud para diagnosticar AUBP mediante CPRM. En caso de que mida entre 6 y 9 mm y la acción del esfínter afecte la unión pancreatobiliar, se lo denomina unión biliopancreática alta (UBPA) y se debe confirmar mediante CPRE. Describimos los hallazgos en imágenes de siete pacientes jóvenes con clínica abdominal y diagnóstico de AUBP o UBPA por CPRM, y además revisamos la literatura sobre el tema.

Abstract Pancreaticobiliary maljunction (PBM) is a congenital malformation in which the pancreatic and biliary ducts are anatomically joined outside the duodenal wall. Due to the excessive length of the common channel, the action of the sphincter does not affect the pancreaticobiliary junction, allowing the reflux of pancreatic juice into the bile duct. It is associated with cysts of the common bile duct and its manifestations include cancer of the bile duct, pancreatitis, choledocholithiasis and cholangitis. It is a rare pathology, especially in Western countries. Magnetic resonance cholangiopancreatography (MRCP) has become the most used method because it is non-invasive, taking into account that endoscopic retrograde cholangiopancreatography (ERCP) is contraindicated in cases of acute pancreatitis and cholangitis, in addition to the risk of pancreatitis after the procedure. The distance between the biliopancreatic junction and the duodenal wall must be greater than 9 mm in length to diagnose PBM by MRCP. If it is between 6 to 9 mm and the action of the sphincter affects the pancreaticobiliary junction, it is called high confluence of pancreaticobiliary ducts (HCPBD) and should be confirmed by ERCP. We describe the imaging findings of 7 young patients with abdominal symptoms and diagnosis of PBM or HCPBD by MRCP, and also review the literature on the subject.

Oncocitomas: hallazgos tomográficos y correlación anatomopatológica / Oncocytomas: Imaging Findings and Anatomopathology Correlation

Introducción: En imágenes, los hallazgos del oncocitoma generalmente coinciden con el carcinoma de células renales (CCR) por lo que resulta muy poco segura su discriminación mediante imágenes. Objetivos: Evaluar el comportamiento de una muestra de oncocitoma en tomografía (TC). Métodos: Se seleccionaron retrospectivamente los pacientes con cirugía de tumor renal y diagnóstico anatomopatológico de oncocitoma, que fueron tratados entre enero de 2015 y diciembre de 2017. Se incluyeron los pacientes a quienes se les realizó TC con medio de contraste endovenoso en nuestra institución. Resultados: Del total de pacientes (n = 44), 43 tenían una lesión única renal, mientras que uno tenía tres lesiones. Del total de las lesiones (n = 47), 20 (42,55 %) fueron diagnosticadas tras una nefrectomía radical y 24 (51,10 %) fueron diagnosticadas por una nefrectomía parcial. La media de diámetro máximo fue de 36,5 mm (RIQ 22-44,25), de los cuales se agruparon en menores y mayores a 4 cm; se encontraron 22 tumores en este último grupo (47 %). De estos, en 15 tumores (31,91 %) que tenían más de 4 cm se encontró la cicatriz central. Se evidenciaron calcificaciones en 3 pacientes (6,8 %). Se encontró 1 tumor (2,1 %) con inversión de realce segmentario luego de la administración medio de contraste endovenoso. En este caso, el oncocitoma era menor a 4 cm. Conclusión: El hallazgo de una masa sólida con realce más intenso que el parénquima circundante durante la fase nefrográfica obliga a considerar al oncocitoma entre los diagnósticos diferenciales

Introduction: The imaging findings of oncocytomas usually coincide with renal cell carcinoma (RCC), which makes it difficult to discriminate them in imaging. Objective: To evaluate the imaging findings of a sample of oncocytomas in tomography (CT). Methods: We retrospectively selected patients with renal tumor surgery and oncocytoma anatomopathological diagnosis, who were treated between January 2015 and December 2017. Patients who underwent CT with intravenous contrast at our institution were included. Results: Of the total number of patients (n = 44), 43 had a single renal lesion while one patient presented 3 lesions. Of the total lesions (n = 47), 20 (42.55%) were diagnosed after a radical nephrectomy and 24 (51.10%) were diagnosed by a partial nephrectomy. The mean maximum diameter was 36.5 mm (RIQ 22-44, 25), of which they were grouped by tumor length into smaller or larger than 4 cm, with 22 tumors in this last group (47%). Of these, 15 tumors (31.91 %) that were larger than 4 cm had a central scar. Calcifications were evident in 3 patients (6.8 %). One tumor (2.1%) was found with the presence of inversion of segmental enhancement after administration of intravenous contrast. In this case, the oncocytoma was less than 4 cm. Conclusion: The finding of a solid mass with more enhancement than the surrounding parenchyma during the nephrographic phase makes it necessary to consider oncocytoma among the differential diagnoses

Prostatitis crónica: Aporte del contraste endovenoso en fase tardía para su caracterización en resonancia magnética multiparamétrica de próstata / Chronic Prostatitis: Contrast Contribution in Late Phase for its Characterization in Multiparametric-Magnetic Resonance Imaging of the Prostate

Resumen Objetivo: El objetivo de este estudio es demostrar la utilidad de una secuencia tardía post-contraste en la resonancia magnética multiparamétrica de próstata (RMMP) para caracterizar lesiones PI-RADS II. Materiales y métodos: Se analizaron en forma retrospectiva las RMMP realizadas entre enero de 2015 y diciembre de 2016. El protocolo de la RMMP fue basado en las recomendaciones del PI-RADS versión 2, y se agregó una adquisición tardía luego del dinámico post-contraste. Los reportes fueron revisados bajo la versión 2.1. Resultados: Se seleccionaron 31 pacientes que presentaron lesiones categorizadas como PI-RADS II en la zona periférica, los cuales se encontraban en seguimiento del antígeno prostático específico y presentaron confirmación histológica de prostatitis crónica. Se evidenció un realce tardío de la lesión en todos los pacientes. Según los resultados histopatológicos, 30 presentaban prostatitis crónica y el restante tejido benigno (tejido fibromuscular). Discusión: La prostatitis crónica no muestra realce temprano, y presenta realce tardío debido al tejido conectivo fibroso que la compone. En la RMMP, la prostatitis puede imitar el cáncer de próstata. Agregar una adquisición tardía solo adiciona 150 segundos al estudio y podría ayudar a resolver aquellos casos inciertos categorizados como PI-RADS III empleando las secuencias convencionales, debido a que el realce tardío de la lesión es altamente sugestivo de un proceso inflamatorio (PI-RADS II). Conclusión: La presencia de realce tardío es una herramienta útil para realizar un adecuado diagnóstico de una lesión PI-RADS II en la zona periférica, pudiendo evitar una biopsia innecesaria.

Abstract Objective: The aim of this study is to demonstrate the utility of a post-contrast late sequence in multiparametric magnetic resonance imaging (RMMP) to characterize PI-RADS II lesions. Materials and methods: The RMMPs performed between January 2015 and December 2016 were retrospectively analyzed. The RMMP protocol was based on the recommendations of the PI-RADS version 2, and a late acquisition was added, after the dynamic post-contrast. The reports were reviewed under the version 2.1. Results: 31 patients with PI-RADS II lesions in the peripheral zone were selected, who were in prostate specific antigen follow-up and had histological confirmation of chronic prostatitis. A late enhancement of the lesion was evidenced in all patients. According to the histopathological results, 30 had chronic prostatitis and the remaining benign tissue (fibromuscular tissue). Discussion: Chronic prostatitis does not show early enhancement, and presents late enhancement due to its fibrous connective tissue. In RMMP, prostatitis may mimic prostate cancer. Adding a late sequence only adds 150 seconds to the study and could help to resolve those uncertain cases categorized as PI-RADS III using traditional sequences because the late enhancement of the lesion is highly suggestive of an inflammatory process (PI-RADS II). Conclusion: The presence of late enhancement is a useful tool to perform an adequate diagnosis of a PI-RADS II lesion in the peripheral zone, helping to avoid an unnecessary biopsy.