A multimodal medical image contrastive learning algorithm with domain adaptive denormalization / 生物医学工程学杂志

Recently, deep learning has achieved impressive results in medical image tasks. However, this method usually requires large-scale annotated data, and medical images are expensive to annotate, so it is a challenge to learn efficiently from the limited annotated data. Currently, the two commonly used methods are transfer learning and self-supervised learning. However, these two methods have been little studied in multimodal medical images, so this study proposes a contrastive learning method for multimodal medical images. The method takes images of different modalities of the same patient as positive samples, which effectively increases the number of positive samples in the training process and helps the model to fully learn the similarities and differences of lesions on images of different modalities, thus improving the model's understanding of medical images and diagnostic accuracy. The commonly used data augmentation methods are not suitable for multimodal images, so this paper proposes a domain adaptive denormalization method to transform the source domain images with the help of statistical information of the target domain. In this study, the method is validated with two different multimodal medical image classification tasks: in the microvascular infiltration recognition task, the method achieves an accuracy of (74.79 ± 0.74)% and an F1 score of (78.37 ± 1.94)%, which are improved as compared with other conventional learning methods; for the brain tumor pathology grading task, the method also achieves significant improvements. The results show that the method achieves good results on multimodal medical images and can provide a reference solution for pre-training multimodal medical images.

Clinical analysis of 30 cases of basal ganglia germinoma in children / 北京大学学报(医学版)

OBJECTIVE@#To summarize and analyze the clinical characteristics of children with basal ganglia germinoma and to improve the level of early clinical diagnosis.@*METHODS@#The clinical data of children diagnosed with basal ganglia germinoma admitted to the Pediatric Surgery Ward of Peking University First Hospital from January 2013 to December 2020 were retrospectively analyzed, and descriptive statistics were used to analyze the clinical characteristics of children with basal ganglia germinoma.@*RESULTS@#A total of 30 patients were included in the study, 28 were male, 2 were female, the mean age at onset was (9.7±2.2) years, the median disease duration was 7 months, 27 had unilateral disease, and 3 had bilateral disease. The clinical manifestations were decreased limb muscle strength, cognitive function disorders, polydipsia, precocious puberty, intracranial hypertension, dysphonia and swallowing dysfunction. The serum and cerebrospinal fluid tumor marker alpha-fetoprotein (AFP) were normal in the 30 patients, and the serum and cerebrospinal fluid tumor marker β-human chorionic gonadotropin (β-HCG) were normal in 8 patients.The serum β-HCG was normal in 11 patients but the cerebrospinal fluid β-HCG was slightly elevated, and the serum and cerebrospinal fluid β-HCG were slightly elevated in 11 patients. A total of 33 lesions with irregular shapes were found by imaging examination, including 15 (45.5%) patchy lesions, 10 (30.3%) patchy lesions, and 8 (24.2%) round-like high-density lesions. Tumors showed obvious high-density shadows on computed tomography (CT) scan. Magnetic resonance imaging (MRI) scan of the tumors showed low or isointensity on T1WI and isointensity on T2WI, accompanied by mild peritumoral edema, hemispheric atrophy, cerebral peduncle atrophy, calcification, cystic degeneration, ventricular dilatation and wallerian degeneration. On contrast-enhanced scans, the tumor showed no enhancement or heterogeneous enhancement.@*CONCLUSION@#The main age of onset of germ cell tumors in the basal ganglia in children is about 10 years old, and males are absolutely dominant. The clinical features and imaging manifestations have certain characteristics. With both combined, the early diagnosis of germ cell tumors in the basal ganglia can be improved.

Primary Extra-axial Glioblastoma: Case Report and Literature Review

Glioblastoma multiforme (GBM) is the most frequent and most aggressive primary brain tumor in adults,mainly located in the cerebral hemispheres. In the literature, few cases of primary GBM have been reported to have radiographic and intraoperative features of extra-axial lesions, leading to a diagnostic dilemma. Despite the advances in imaging modalities, the diagnosis of GBM can be challenging, and it is mainly based on the histopathologic confirmation of the excised tumor. We describe the case of a 76- year-old previously healthy female patient who presented to our hospital due to speech disturbances and cognitive impairment. The diagnosis of the tumor type on magnetic resonance imaging (MRI) was difficult, as the findings were suggestive of a malignant meningioma due to the heterogeneous enhancement of a dural-based mass with a dural tail sign. Moreover, the intraoperative findings revealed an extra-axial mass attached to the dura. A histological examination confirmed the diagnosis of glioblastoma with arachnoid infiltration. The patient underwent adjuvant radiotherapy and concomitant temozolomide treatment, she had clinical improvement postoperatively, and was stable during the six months of follow-up. Glioblastoma should be considered in the differential diagnosis of primary extra-axial mass with atypical and malignant features, especially in elderly patients.

Microsurgical Resection of Glioblastoma in a Patient Infected with Covid-19: A Case Report

The COVID-19 pandemic has affected a large number of patients in all countries, overwhelming healthcare systems worldwide. In this scenario, surgical procedures became restricted, causing unacceptable delays in the treatment of certain pathologies, such as glioblastoma. Regarding this tumor with high morbidity and mortality, early surgical treatment is essential to increase the survival and quality of life of these patients. Association between COVID-19 and neurosurgical procedures is quite scarce in the literature, with a few reported cases. In the present study, we present a rare case of a patient undergoing surgical resection of glioblastoma with COVID-19.

Utility of Intraoperative Ultrasound in Neurosurgery

Objective The purpose of the present study is to demonstrate the usefulness of intraoperative ultrasound guidance as a technique for the assessment, in real time, of tumor resection and as a navigation aid during intra-axial brain lesion removal on patients admitted in the Neurosurgical Department at the Hospital Universitario de Caracas, Caracas, Venezuela, in 2018. Methods A total of 10 patients were enrolled, each with intra-axial brain lesions with no previous neurosurgical procedures and a mean age of 49 years old, ranging from 29 to 59 years old. Results A male predominance was observed with 7 cases (70%) over 3 female cases (30%). Six patients had lesions in the dominant hemisphere. The frontal lobe was the most commonly affected,with 5 cases, followed by the parietal lobe,with 4 cases. After craniotomy, ultrasound evaluation was performed previously to dural opening, during tumor resection and after tumor removal. The mean tumor size in axial, coronal and sagittal views was 3.72 cm, 3.08 cm and 3.00 cm, respectively, previously to dural opening with intraoperative ultrasound. The average tumor depth was 1.73 cm from the cerebral cortex. The location and removal duration from the beginning of the approach (ultrasound usage time) was 83.60 minutes, and the average surgery duration was 201 minutes. Navigation with intraoperative ultrasound served to resect intra-axial tumors more precisely and safely. There was no postoperative complication associated with the surgery in this series of cases. Conclusions Intraoperative ultrasound guidance for intra-axial subcortical tumor resection is a technique that serves as a surgical and anatomical orientation tool.

Evaluación de la actividad cerebro-cerebelar cruzada para determinar la lateralidad del lenguaje en pacientes con tumores cerebrales / Evaluation of the crossed cerebro-cerebellar activation to determine language lateralization in patients with brain tumors

Background: The crossed cerebro-cerebellar (CCC) activation facilitates the diagnosis of cortical language lateralization, but needs to be explored with language tasks suitable for patients with different age ranges, educational attainment and eventual presence of language deficits. Aim: To determine the effect of demographic variables in the performance of three language tasks in healthy volunteers and to determine the CCC activation of these tasks as a functional magnetic resonance imaging (fMRI) paradigm in brain tumor patients. Material and Methods: The behavioral performance (correct responses and reaction time) of three language tasks (verbal fluency, semantic and phonological decision tasks) was first examined in 76 healthy volunteers balanced by age and educational level. Later, these tasks were implemented as fMRI paradigms to explore CCC language activation of 20 patients with potential diagnosis of brain tumors. Results: The performance of the verbal fluency task was affected by age. The CCC language activation was reproducible with the semantic and phonological tasks. The combination of the tasks determined typical and atypical language lateralization in 60% and 40% of our patients, respectively. Conclusions: The verbal fluency task must be implemented with care as a clinical fMRI paradigm. Our results suggest that semantic and phonological tasks can be a good alternative for brain tumor patients with language deficits.

Marcadores moleculares y biomarcadores de imagen: importancia en el avance terapéutico de los tumores cerebrales intraaxiales / Molecular markers and image biomarkers. Importance in the therapeutic advance of intraaxial brain tumors

RESUMEN: La clasificación de los Tumores Primarios del Sistema Nervioso Central (SNC) tiene su origen en la descripción morfológica, cuyo análisis histopatológico ha permitido identificar la línea celular involucrada en estos tumores y obtener el reconocimiento de ciertas características de estas lesiones y su evolución clínica. El estudio molecular ha venido a complementar el diagnóstico inicial permitiendo reconocer entidades que no son distinguibles de otra manera y que han variado los conceptos y definiciones de varias entidades patológicas que modifican el horizonte visible de estas enfermedades. El papel de las imágenes de Resonancia Magnética (RM) en el manejo de los tumores intraaxiales se puede dividir ampliamente en el diagnóstico y la clasificación de los tumores, la planificación del tratamiento y el tratamiento posterior. El presente artículo resume la evidencia epidemiológica relacionada en la clasificación de los tumores primarios del SNC con marcadores moleculares y biomarcadores de imágenes de RM, apuntando a la importancia del uso de la investigación clínica con el manejo terapéutico.

SUMMARY: The classification of primary tumors of the Central Nervous System (CNS) has its origin in the morphological description whose histopathological analysis has allowed to identify the cell line involved in these tumors and obtain the recognition of certain characteristics of these lesions and their clinical evolution. The molecular study has come to complement the initial diagnosis allowing to recognize entities that are not distinguishable in another way and that have varied the concepts and definitions of various pathological entities modifying the visible horizon of these diseases. The role of Magnetic Resonance (MR) images in the management of intraaxial tumors can be broadly divided into the diagnosis and classification of tumors, treatment planning and subsequent treatment. The present article summarizes the epidemiologic evidence related to the classification of primary tumors of the CNS with molecular markers and MR imaging biomarkers.

Biomarcadores radiológicos en RM para una aproximación al diagnóstico molecular en gliomas IDH-mutados (grado II y III) / MR Imaging Biomarkers for a Diagnostic Approach of IDH-mutated Gliomas (Grades II/III)

Resumen Objetivo: Analizar características por resonancia magnética (RM) de gliomas IDH-mutados (grado II y III) en base a parámetros cualitativos, a fin de valorar el rendimiento del signo del mismatch T2-FLAIR y otras características morfológicas de los tumores, en predecir el estado del 1p/19q y su reproducibilidad interobservador. Métodos Estudio retrospectivo, descriptivo y analítico sobre una cohorte de 53 gliomas IDH-mutados (grado II y III) y molecularmente definidos respecto al 1p/19q, seleccionados a partir de la base de datos de la institución, durante el periodo 2014- 2019. Dos neuroradiólogos evaluaron características imagenológicas de forma independiente y enmascarada al diagnóstico: mismatch T2-FLAIR, localización tumoral, bordes, señal, infiltración cortical e inhomogeneidad en T2. Los casos discordantes fueron evaluados por un tercer neuroradiólogo de mayor experiencia. Resultados: Treinta de 53 (56,6%) gliomas fueron no codelecionados, y 23/53 (43,4%) codelecionados. El signo del mismatch T2-FLAIR fue positivo en 16/53 (30,18%) pacientes, 15/16 (93,75%) no codelecionados y 1/16 (6,25%) codelecionado (Exacto de Fisher p = <,0001). Los dos evaluadores demostraron una concordancia interobservador casi perfecta para ese signo, κ =,907 (95% CI, 0,781 a 1,0). La especificidad y el valor predictivo positivo del signo para predecir la ausencia de la codeleción fue de un 95,7% y un 93,8% respectivamente. Discusión: La reciente actualización en la clasificación de los gliomas los clasifica acorde a su perfil molecular. En los últimos años, varios investigadores han estudiado características morfológicas por RM de los tumores con la intención de predecir las características moleculares de los mismos. Conclusión: En nuestra población, el signo del mismatch T2-FLAIR es el único biomarcador radiológico que muestra asociación estadísticamente significativa en predecir la ausencia de codeleción en los gliomas IDH-mutados (grado II y III), con una alta especificidad y un alto valor predictivo positivo.

Abstract Objective: To analyze magnetic resonance (MR) characteristics of IDH-mutated gliomas (grades II/III) utilizing qualitative parameters with the goal of assessing the performance of the T2-FLAIR mismatch sign and other morphological characteristics of tumors in predicting the 1p/19q co-deletion status as well as inter-observer reproducibility. Methods: Retrospective and descriptive study analyzing a cohort of 53 IDH-mutated lower-grade (grades II/III) gliomas with known 1p/19q co-deletion status. Patients meeting selection criteria for this study were taken from our institutional data from 2014-2019. Two neuroradiologists assessed the following imaging characteristics independently, and blinded from the diagnosis: T2-FLAIR mismatch, tumor location, borders, signal characteristics, cortical infiltration and T2* inhomogeneity. In the event of discordant interpretations, a third senior neuroradiologist also evaluated the case. Results: 23 of the 53 (43.4%) gliomas demonstrated 1p/19q co-deletion and 30 of 53 (56.6%) did not. T2-FLAIR mismatch was positive in 16 of 53 cases (30.2%) with 15 of 16 (93.8%) demonstrating no co-deletion and 1/16 (6.25%) with co-deletion (Fisher's exact p = < .0001). The two readers showed an almost perfect interreader agreement for this sign κ = 0.907 (95% CI, 0.781 to 1.0). Specificity and positive predictive value of the sign to predict the absence of co-deletion was 95.7% and 93.8% respectively. Discussion: The recent update in classification of lower-grade gliomas segregates gliomas according to molecular profile. In the recent past, many researchers have studied MR morphologic characteristics of these tumors with the intention of predicting molecular features of said tumors Conclusion: In our patient population, T2-FLAIR mismatch sign is the only radiologic biomarker that shows statistically significant association with the absence of 1p/19q co-deletion in lower-grade gliomas, with high specificity and positive predictive value.

Lesiones oncológicas intracraneales de apariencia quística / Oncologic Intracranial Lesions with Cystic Appearance

Resumen La presencia de lesiones quísticas de etiología oncológica en el encéfalo es cada vez más frecuente. El rol del especialista en imágenes es describir sus características, morfología y comportamiento con el contraste endovenoso, para llegar a realizar un diagnóstico presuntivo y enumerar sus diagnósticos diferenciales, y así orientar al médico tratante. Haremos una revisión de las lesiones quísticas de etiología oncológica de presentación frecuente en el encéfalo.

Abstract The presence of an oncologic cystic formation in the brain is frequent. The imaging specialist's role is to describe its features, morphology, and image enhancement characteristics with endovenous contrast, to make a presumptive diagnosis, and enumerated differential diagnoses and thus orientate the practitioner. We will analyze the most common expansive cystic formations.

Automated grading of glioma based on density and atypia analysis in whole slide images / 生物医学工程学杂志

Glioma is the most common malignant brain tumor and classification of low grade glioma (LGG) and high grade glioma (HGG) is an important reference of making decisions on patient treatment options and prognosis. This work is largely done manually by pathologist based on an examination of whole slide image (WSI), which is arduous and heavily dependent on doctors' experience. In the World Health Organization (WHO) criteria, grade of glioma is closely related to hypercellularity, nuclear atypia and necrosis. Inspired by this, this paper designed and extracted cell density and atypia features to classify LGG and HGG. First, regions of interest (ROI) were located by analyzing cell density and global density features were extracted as well. Second, local density and atypia features were extracted in ROI. Third, balanced support vector machine (SVM) classifier was trained and tested using 10 selected features. The area under the curve (AUC) and accuracy (ACC) of 5-fold cross validation were 0.92 ± 0.01 and 0.82 ± 0.01 respectively. The results demonstrate that the proposed method of locating ROI is effective and the designed features of density and atypia can be used to predict glioma grade accurately, which can provide reliable basis for clinical diagnosis.

Clinicopathological Analysis of Brain Metastatic Carcinoma in Tibet / 中国医学科学院学报

Objective To investigate the clinicopathological features and immunohistochemical phenotypes of brain metastatic carcinoma in Tibetan patients. Methods The clinical and pathological data of all patients with brain metastases from 2014 to 2020 in Tibet Autonomous Region People's Hospital were retrospectively analyzed,including 13 cases of brain metastatic carcinoma.All cases were diagnosed and classified by immunohistochemical staining. Results 13 cases(9 males and 4 females)of brain metastatic carcinoma,aged 26-62 years old,present with headache,dizziness,nausea and vomiting clinically.Four patients had a medical history of tumor,and among the 9 patients with no history of tumor,7 present space occupying lesions in both the brain and other organs.Imaging data could be found in 10 cases,including 4 cases of single lesion and 6 cases of multiple lesions.Primary tumors were identified in 11 cases(8 located in the lung,including 4 cases of adenocarcinoma,3 cases of small cell carcinoma,and 1 case of squamous cell carcinoma;1 case of urothelial carcinoma of the renal pelvis;1 case of thyroid papillary carcinoma;1 case of uterine choriocarcinoma),whereas the primary tumor was unknown for the other 2 cases(1 case of small cell carcinoma and 1 case of adenocarcinoma). Conclusions Brain metastatic carcinoma are more common among middle-aged and elderly people in Tibet.Most of the cases have no history of tumor,with the initial site at the brain metastatic lesions.The most common primary site is the lung,and the primary site of some cases is unknown.Multiple lesions are common in brain metastatic carcinoma,especially in the cerebral hemisphere.For older patients with multiple brain space occupying lesions,the possibility of brain metastatic carcinoma increases.

Advances in Radiomics of Cerebral Metastases / 中国医学科学院学报

Cerebral metastases are the most common intracranial tumors in adults,with an increasing incidence in recent years.Radiomics can quantitatively analyze and process medical images to guide clinical practice.In recent years,CT and MRI-based radiomics has been gradually applied to the precise diagnosis and treatment of cerebral metastases,such as the precise detection and segmentation of tumors,the differential diagnosis with other cerebral tumors,the identification of primary tumors,the evaluation of treatment efficacy,and the prediction of prognosis.This article reviews the advances in radiomics of cerebral metastases.

Application of Magnetization-prepared True Fast Imaging with Steady-state Precession Sequence in Brain Tumor Enhancement / 中国医学科学院学报

Objective To evaluate the application of two-dimensional magnetization-prepared true fast imaging with steady-state precession(2D-MP-TrueFISP)sequence in brain tumor enhancement.Methods In this study,60 cases of brain tumor patients who underwent enhanced magnetic resonance imaging of brain were scanned with 2D-MP-TrueFISP/two-dimensional spoiled gradient-recalled echo(2D-SPGR)before and after enhancement.The scores of lesions on the images of 2D-MP-TrueFISP/2D-SPGR were compared.At the same level of 2D-SPGE and 2D-MP-TrueFISP,the signal intensities(SIs)of lesions,white matter,and cerebrospinal fluid were measured before and after enhancement,and the contrast ratios(CRs)of lesions were calculated.The CRs before and after 2D-SPGR/2D-MP-TrueFISP enhancement and those between 2D-SPGR and 2D-MP-TrueFISP after enhancement were compared.Results The scores of lesions after 2D-MP-TrueFISP/2D-SPGR T1WI enhancement were 9.0(9.0,9.0)and 7.0(6.0,7.0),respectively,with significant difference(

A logistic regression model for prediction of glioma grading based on radiomics / 中南大学学报(医学版)

OBJECTIVES@#Glioma is the most common intracranial primary tumor in central nervous system. Glioma grading possesses important guiding significance for the selection of clinical treatment and follow-up plan, and the assessment of prognosis. This study aims to explore the feasibility of logistic regression model based on radiomics to predict glioma grading.@*METHODS@#Retrospective analysis was performed on 146 glioma patients with confirmed pathological diagnosis from January, 2012 to December, 2018. A total of 41 radiomics features were extracted from contrast-enhanced T@*RESULTS@#A total of 5 imaging features selected by LASSO were used to establish a logistic regression model for predicting glioma grading. The model showed good discrimination with AUC value of 0.919. Hosmer-Lemeshow test showed no significant difference between the calibration curve and the ideal curve (@*CONCLUSIONS@#The logistic regression model using radiomics exhibits a relatively high accuracy for predicting glioma grading, which may serve as a complementary tool for preoperative prediction of giloma grading.

CT and Magnetic Resonance Imaging Findings of the Intracranial Extra-cerebral Chondroma:A Case Report / 中国医学科学院学报

Intracranial intradural chondroma is a rare disorder,the imaging findings of which have been rarely reported.The current study reported a case of intracranial extra-cerebral chondroma and described the detailed CT and magnetic resonance imaging findings,which would provide valuable imaging evidence for the diagnosis of intracranial extra-cerebral chondroma.

Supervivencia prolongada luego de pequeñas dosis de terapia con radioyodo en metástasis cerebral de cáncer de tiroides / Long-term survival after small doses of radioiodine therapy for brain metastases of thyroid cancer

Resumen El cáncer diferenciado de tiroides generalmente se acompaña de una supervivencia a largo plazo. Sin embargo, en algunos casos pueden desarrollarse metástasis a distancia y, entre ellas, las localizaciones cerebrales son de mal pronóstico. El objetivo de esta presentación es comunicar el caso clínico de una mujer de 65 años que consultó por diplopía en la mirada vertical que había aparecido un mes antes. La resonancia magnética mostró una gran masa a nivel del cóndilo occipital. Se realizó el diagnóstico de tumor cerebral primario, por lo que fue operada dos veces con resección tumoral incompleta. El estudio histopatológico confirmó una lesión metastásica de carcinoma de tiroides. Se realizó una tiroidectomía total con resección de un cáncer papilar de la variante folicular. Luego, fue tratada con éxito con pequeñas cantidades repetitivas de yodo radiactivo para una dosis total acumulada de 325 mCi 131I, con una supervivencia a largo plazo.

Abstract Differentiated thyroid cancer is generally accompanied by a long term survival. However,in some cases distant metastases can develop and among them, brain localizations are of poor prognosis. The aim of this presentation is to communicate the clinical case of a 65 year-old woman who consulted for diplopia in vertical gaze which had appeared one month earlier. MRI showed a big mass at the level of the occipital condyle. Diagnosis of primary brain tumor was made so she was operated twice with incomplete tumor resection. The pathological study was confirmatory of a metastatic lesion of thyroid carcinoma. A total thyroidectomy with resection of a papillary cancer of the follicular variant was performed. Then, she was successfully treated with small repetitive radioiodine amounts for a total accumulated dose of 325 mCi 131I, with a long-term survival.

Pilocytic astrocytoma, another way to reach your diagnosis / Astrocitoma pilocítico, outra forma de chegar ao seu diagnóstico

Abstract Cerebellar astrocytoma (low-grade glioma) is the most frequent tumor of the Central Nervous System in pediatric age, corresponding to 10-20% of brain tumors, having its maximum incidence at 5 years. Brain tumors are the second cause of death at this age, behind leukemias. Its most frequent clinic is headache with vomiting which can worsen in the morning and awaken the patient at night. The most frequent ophthalmological clinic is papilledema and involvement of the cranial nerve VI. In our case we present an atypical presentation (cranial IV), in which a quick derivation favored a better prognosis.

Resumo O astrocitoma cerebelar (glioma de baixo grau) é o tumor mais frequente do Sistema Nervoso Central em idade pediátrica, correspondendo a 10-20% dos tumores cerebrais, tendo sua incidência máxima em 5 anos. Os tumores cerebrais são a segunda causa de morte nesta idade, atrás das leucemias. Sua clínica mais frequente é a cefaleia com vômitos que podem piorar pela manhã e despertar o paciente à noite. A clínica oftalmológica mais frequente é o papiledema e o envolvimento do nervo craniano VI. Em nosso caso apresentamos uma apresentação atípica (IV craniana), em que uma derivação rápida favoreceu um melhor prognóstico.

Oligodendroglioma anaplásico quístico: reporte de caso / Anaplastic cystic oligodendroglioma: case report

Resumen: Los oligodendrogliomas anaplásicos son gliomas infiltrantes grado III de la organización mundial de la salud (OMS). Son tumores poco frecuentes y representan el 5-10% de todas las neoplasias intracraneales primarias. Su incidencia es de 0.3 por 100.000 habitantes por año en Estados Unidos. Con frecuencia se presentan en adultos entre los 40-60 años de edad. Los síntomas principales pueden ser déficit motor, déficit cognitivos y síntomas de aumento de la presión intracraneal. Su comportamiento en resonancia magnética muestra un aspecto heterogéneo con necrosis, degeneración quística y hemorragia intratumoral. Las presentaciones quísticas extensas son poco frecuentes. Reportamos el caso de un oligodendroglioma anaplásico de aspecto predominantemente quístico en una mujer joven.

Abstract: Anaplastic oligodendrogliomas are grade III infiltrating gliomas of the World Health Organization (WHO). They are rare tumors and represent 5-10% of all primary intracranial neoplasms. Its incidence is 0.3 per 100.000 inhabitants per year in the United States. They often occur in adults between 40-60 years of age. The main symptoms may be motor deficit, cognitive deficits and symptoms of increased intracranial pressure. Its behavior in MRI shows a heterogeneous appearance with necrosis, cystic degeneration and intratumoral hemorrhagic. Extensive cystic presentations are rare. We report the case of an anaplastic oligodendroglioma of predominantly cystic appearance in a young woman.

Gliosarcomas: magnetic resonance imaging findings / Gliossarcomas: achados de ressonância magnética

Abstract Background: Central nervous system (CNS) gliosarcoma (GSM) is a rare primary neoplasm characterized by the presence of glial and sarcomatous components. Objective: In this report, we describe the clinical and neuroimaging aspects of three cases of GSM and correlate these aspects with pathological findings. We also provide a brief review of relevant literature. Methods: Three patients were evaluated with magnetic resonance imaging (MRI), and biopsies confirmed the diagnosis of primary GSM, without previous radiotherapy. Results: The analysis of conventional sequences (T1, T1 after contrast injection, T2, Fluid attenuation inversion recovery, SWI and DWI/ADC map) and advanced (proton 1H MR spectroscopy and perfusion) revealed an irregular, necrotic aspect of the lesion, peritumoral edema/infiltration and isointensity of the solid component on a T2-weighted image. These features were associated with irregular and peripheral contrast enhancement, lipid and lactate peaks, increased choline and creatine levels in proton spectroscopy, increased relative cerebral blood volume (rCBV) in perfusion, multifocality and drop metastasis in one of the cases. Conclusion: These findings are discussed in relation to the general characteristics of GSM reported in the literature.

Resumo Introdução: O gliossarcoma (GSM) do sistema nervoso central (SNC) é uma neoplasia primária rara, caracterizada pela presença de componentes gliais e sarcomatosos. Objetivo: Nosso objetivo é descrever os aspectos clínicos e de neuroimagem de três casos com este diagnóstico e correlacioná-los com os achados patológicos. Também foi realizada uma breve revisão da literatura relevante. Métodos: Três pacientes foram avaliados por ressonância magnética (RM), e biópsias confirmaram o diagnóstico de GSM primário, sem radioterapia prévia. Resultados: Foram analisadas as sequências convencionais (T1, T1 após injeção de contraste, T2, FLAIR-fluid attenuation inversion recovery, SWI, DWI/mapa ADC) e as sequências avançadas (espectroscopia de prótons 1H e perfusão), observando-se aspecto necrótico e irregular da lesão, edema/infiltração peritumoral, isointensidade do componente sólido em T2, associada a realce irregular e periférico pelo meio de contraste, pico de lípides e de lactato e aumento dos níveis de colina e creatina na espectroscopia de prótons, aumento do volume sanguíneo cerebral relativo (rCBV) na perfusão, multifocalidade e "drop" mestástase em um dos casos. Conclusão: O presente estudo descreve características do GSM, discutindo as informações na literatura científica, ilustrando algumas particularidades desses tumores.