中枢神经系统非典型畸胎瘤样／横纹肌样瘤的影像学表现及研究进展

中枢神经系统非典型畸胎瘤样／横纹肌样瘤是近年来新认识的好发于婴幼儿/儿童中枢神经系统的罕见肿瘤,预后极差,临床容易误诊。CT、脚表现无诊断特异性,但在肿瘤的定位和鉴别诊断上具有重要价值。本文主要对此肿瘤的命名、病理学特点和临床特征、影像学表现作一综述。     

Neuroradiological findings in atypical teratoid/rhabdoid tumor of the central nervous system

PURPOSE: To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) findings of atypical teratoid tumor/rhabdoid tumor (AT/RT) of the central nervous system (CNS). MATERIAL AND METHODS: Twenty cases of CNS AT/RT have been found over the past 23 years in our hospital; these involving 11 boys and 9 girls whose mean age at diagnosis was 5.5 years. Their clinical data, the CT, and MRI findings were reviewed retrospectively. RESULTS: AT/RT was located in the cerebellum in 15 cases. Four cases arose from the supratentorial region, while only one occurred primarily in the lumbar spinal cord. Almost all cases revealed heterogeneous intensity and heterogeneous enhancement. Peripheral cystic components were common. Survival time ranged from 2 months to 3 years, with a mean survival of 11.6 months. CONCLUSION: Most cases of AT/RT are located in the cerebellum. The radiologic manifestations are non-specific. The diagnosis mainly depends on the pathologic findings. However, AT/RT should still remain in the differential diagnosis of brain tumors in young children, especially those located in the cerebellar hemisphere and with eccentric cysts.     

Atypical teratoid/rhabdoid tumors in adult patients: CT and MR imaging features

Primary AT/RT is a rare highly malignant tumor of the CNS, usually occurring in children younger than 5 years of age. The objective of this study was to characterize the CT and MR imaging findings in a series of 5 adult patients with pathologically proved AT/RT. All 5 AT/RTs were supratentorial. In 2 patients who underwent nonenhanced CT, the tumors appeared isoattenuated, and 1 of the 2 tumors contained calcifications. Solid portions of the tumors on MR imaging were isointense on T1-weighted, T2-weighted, and FLAIR images, and 1 case showed restricted diffusion on DWI. The tumors also demonstrated a bandlike rim of strong enhancement surrounding a central cystic area on contrast-enhanced T1-weighted imaging. One tumor was associated with destruction of the calvaria. Although AT/RTs can have nonspecific findings, the tumors in our series were large and isointense on T1-weighted, T2-weighted, and FLAIR images with central necrosis and prominent rim enhancement.     

Central nervous system atypical teratoid/rhabdoid tumour of infancy. CT and mr findings

In 1995, as a result of the observation of Rhabdoid elements among the other components of a Teratoid/Rhabdoid tumor (TRT), a new nomenclature was introduced, Atypical Teratoid/Rhabdoid Tumor (ATRT) of infancy and childhood. We report the clinical history and radiological findings in a child affected by central nervous system (CNS) ATRT.     

Primary diffuse leptomeningeal atypical teratoid rhabdoid tumor (AT/RT) demonstrating atypical imaging findings in an adolescent patient

Atypical teratoid rhabdoid tumor (AT/RT) is a highly malignant central nervous system embryonal tumor, which typically affects the posterior fossa of young children. Primary diffuse leptomeningeal AT/RT, affecting the leptomeninges without any intraparenchymal mass in the brain and spinal cord, is an extremely rare form of AT/RT. Only 5 such cases have been reported previously, none of which underwent Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography (FDG-PET). We herein report a case of primary leptomeningeal AT/RT in an adolescent patient who underwent computed tomography, magnetic resonance imaging and FDG-PET. The computed tomography and magnetic resonance imaging indicated diffusely thickened leptomeninges without any intraparenchymal masses in the head and spine. Furthermore, there were multiple nodules on the thickened leptomeninges. On FDG-PET, the thickened leptomeninges and nodules demonstrated a lower standardized uptake value than that of the normal cerebral cortex. Biopsy and histopathological studies confirmed the diagnosis of AT/RT. Despite its rare occurrence, it is important to recognize primary diffuse leptomeningeal AT/RT for correct diagnosis and management of patients.     

Cross-sectional imaging with CT and/or MRI of pediatric chest tumors

The purpose of this study was to provide an overview of the spectrum of pediatric chest masses, to present the results of cross-sectional imaging with CT and/or MRI, and to define diagnostic criteria to limit differential diagnosis. Seventy-eight children with thoracic mass lesions were retrospectively evaluated using CT (72 patients) and/or MR imaging (12 patients). All masses were evaluated for tissue characteristics (attenuation values or signal intensity, enhancement, and calcification) and were differentiated according to age, gender, location, and etiology. Twenty-eight of 38 (74 %) mediastinal masses were malignant (neuroblastoma, malignant lymphoma). Thirty of 38 (79 %) pulmonary masses were metastatic in origin, all with an already known primary tumor (osteosarcoma, Wilms tumor). With one exception, all remaining pulmonary lesions were benign. Seventeen of 21 (81 %) chest wall lesions were malignant (Ewing sarcoma, primitive neuroectodermal tumor). The majority of mediastinal and chest wall tumors in children is malignant. Lung lesions are usually benign, unless a known extrapulmonary tumor suggests pulmonary metastases. Cross-sectional imaging with CT and/or MRI allows narrowing of the differential diagnosis of pediatric chest masses substantially by defining the origin and tissue characteristics. Magnetic resonance imaging is preferred for posterior mediastinal lesions, whereas CT should be used for pulmonary lesions. For the residual locations both modalities are complementary. Received 7 March 1997; Revision received 9 September 1997; Accepted 14 November 1997     

Imaging findings of CNS atypical teratoid/rhabdoid tumors

Four patients with brain tumors were diagnosed with atypical teratoid/rhabdoid tumors and underwent CT and MR imaging. For all tumors, aggressive features were shown by imaging studies and included hydrocephalus, apparent invasion of the adjacent brain and dura, and marked mass effect. The striking heterogeneity of the atypical teratoid/rhabdoid tumor shown by imaging studies reflects the histopathologic complexity of these tumors, and awareness of atypical teratoid/rhabdoid tumor is important in making the correct diagnosis of this uncommon but probably underdiagnosed entity.     

CT and MR imaging findings of palatal tumors

Palatal tumors commonly arise from the minor salivary glands, and benign tumors account for approximately half of all minor salivary gland tumors. Minor salivary gland tumors have an affinity for the posterior hard palate and soft palate and virtually never arise in the midline, probably because of the distribution of palatal salivary glands. The majority of benign salivary gland tumors of the palate are pleomorphic adenomas, while the most common malignant salivary gland tumor is adenoid cystic carcinoma, followed by mucoepidermoid carcinoma, adenocarcinoma, and polymorphous low-grade adenocarcinoma. Epithelial tumors frequently arise from the soft palate. The majority of benign epithelial tumors of the palate are papillomas, while most malignant epithelial tumors are squamous cell carcinomas. Various types of mesenchymal tumors, including fibromas, lipomas, schwannomas, neurofibromas, hemangiomas, and lymphangiomas, also involve the palate. This article describes the CT and MR findings of benign and malignant palatal tumors.     

CT and MR imaging findings of endocrine tumor of the pancreas according to WHO classification

The pancreatic endocrine tumors are rare neuroendocrine tumors of the pancreas originating from totipotential stem cells or differentiated mature endocrine cells within the exocrine gland. Endocrine tumors are usually classified into functioning and non-functioning tumors and presents with a range of benignity or malignancy. In this article, we present the various CT and MR imaging findings of endocrine tumors of pancreas according to recent WHO classification.     

颅内非典型畸胎瘤样/横纹肌样瘤的影像学表现（附6例报道）

目的：探讨颅内非典型畸胎瘤样／横纹肌样瘤（AT／RT）的影像学特征。方法：回顾性分析2010年10月－2014年6月经病理和免疫组化诊断为 AT／RT 的6例患者的 CT（n＝3）和 MRI（n＝6）表现,并进行相关文献复习。结果：6名患者平均年龄2．05岁。肿瘤位于幕上4例,幕下1例,幕上及幕下多发病灶1例。肿瘤最大径30～96 mm,平均（59±24）mm。囊变6例,出血4例,钙化2例,所有病灶都有中重度强化。病灶扩散加权成像（DWI）呈不均匀高信号,表观扩散系数（ADC）值（0．70±0．12）×10－3 mm2／s 。1例病灶侵犯邻近硬膜及颅骨;1例病灶发生柔脑膜种植。2例患者术后随访 MRI 时病灶复发。结论：虽然颅内 AT／RT 无特异性影像学表现,但当肿瘤较大、伴有囊变及出血、低 ADC 值及脑脊液播散时,不应排除 AT／RT 的诊断。     

Noninvasive diagnostic assessment of brain tumors using combined in vivo MR imaging and spectroscopy.

To determine the potential value of multimodal MRI for the presurgical management of patients with brain tumors, we performed combined magnetic resonance imaging (MRI) and proton MR spectroscopy (MRS) in 164 patients who presented with tumors of various histological subtypes confirmed by surgical biopsy. Univariate statistical analysis of metabolic ratios carried out on the first 121 patients demonstrated significant differences in between-group comparisons, but failed to provide sufficiently robust classification of individual cases. However, a multivariate statistical approach correctly classified the tumors using linear discriminant analysis (LDA) of combined MRI and MRS data. After initial separation of contrast-enhancing and non-contrast-enhancing lesions, 91% of the former and 87% of the latter were correctly classified. The results were stable when this diagnostic strategy was tested on the additional 43 patients included for validation after the initial statistical analysis, with over 90% of correct classification. Combined MRI and MRS had superior diagnostic value compared to MRS alone, especially in the contrast-enhancing group. This study shows the clinical value of a multivariate statistical analysis based on multimodal MRI and MRS for the noninvasive evaluation of intracranial tumors.     

中枢神经系统肿瘤的MRI影像标注专家共识

随着人工智能（AI）技术在医学影像领域广泛应用,数据的标准化是关键。医学影像数据的标注是其中的重要环节,标注的质量直接决定了AI模型的效能。目前AI技术已经用于中枢神经系统肿瘤性疾病的多方面研究。为了规范中枢神经系统肿瘤数据的标注,中国医师协会放射医师分会“互联网+”医学影像专委会联合业内影像医学、计算机科学和人工智能科技企业的专家结合实践操作并反复讨论,对中枢神经系统肿瘤的MRI影像标注提出初步指导意见,旨在统一数据采集及标注规则,从而提高模型的泛化性,促进AI技术的优化、验证及推广。     

Application of contrast agents in CT and MRI (NMR): their potential in imaging of brain tumors

Summary 21 patients with clinical and CT diagnoses of intracranial tumor were studied by MRI (NMR) prior to and after administration of intravenous Gadolinium-DTPA. Resultant MRI images were compared with corresponding CT sections with respect to lesion detection, contrast enhancement, tumor delineation and visualization of perifocal edema. All intracranial lesions shown on CT were identified on MRI. Contrast enhancement in MRI images was achieved in 19 out of 21 patients, as it was also with CT. In these cases improved differentiation between tumor, perifocal edema and adjacent brain structures were obtained. In most cases sufficient visualization of perifocal edema in MRI required T₂ weighted images (SE 1600/70) in addition to spin echo scans routinely performed prior to and after contrast medium (SE 400/30 or 800/30). No side effects were encountered following administration of Gadolinium-DTPA. The good tolerance and the efficacy justifies the use of Gadolinium-DTPA for contrast enhanced MRI imaging.Dedicated to Professor S. Wende on the occasion of his 60th birthday     

MR imaging in tumors of the pineal region

Summary Ten patients with tumors of the pineal region underwent CT and MRI investigations. There were 3 germinomas, 3 teratomas and 1 of each of the following: pineocytoma, PNET, ependymoma and meningioma. Not only were tumor size and growth compared to CT, but an attempt was made to obtain knowledge of the histology of the tumor by special T₂ calculations. The investigations did not lead to an improvement in type specific diagnosis.Dedicated to Prof. Dr. Peiffer on the occasion of his 65th birthday     

Non-Hodgkin's lymphoma of the nasopharynx: CT and MR imaging

OBJECTIVE: Nasopharyngeal (NP) non-Hodgkin's lymphoma (NHL) is an uncommon tumour. The aim of the study was to describe the appearances on CT and MR imaging, and identify the features which help to distinguish NPNHL from other NP tumours. MATERIALS AND METHODS: The CT (n=8) and MR (n=10) images of 14 patients with NPNHL were reviewed retrospectively. Patients with NPNHL were divided into primary NPNHL, where the primary tumour was in the NP (n=7) and secondary NPNHL where the primary tumour was at another extranodal site in the head and neck (n=7). All NPNHL were assessed for tumour size and distribution, appearance and local tumour invasion, in addition lymphadenopathy was assessed in primary NPNHL. RESULTS: The NPNHL ranged in size from 20-75 mm (mean of 55 mm for primary and 30 mm for secondary NHL) and were homogeneous on CT in eight (100%) and MR in seven (70%) and mildly heterogeneous on MR in three (30%) patients. NPNHL involved all walls of the NP in 10 (71%) (n=1). Primary NPNHL extended superficially in five (71%) to involve the nasal cavity (n=3) and oropharynx (n=2) and lymphadenopathy was present in five (71%) being bilateral and involving multiple nodal sites (n=4) with necrosis (n=2) and matting (n=3). CONCLUSION: NPNHL is a homogeneous tumour that tends to diffusely involve all walls of the nasopharynx and spread in an exophytic fashion to fill the airway, rather than infiltrating into the deep tissues. Deep tumour infiltration, when it occurs, is found in those patients with primary NHL and is usually limited in extent and of small volume. and extended in an exophytic fashion to fill the NP cavity in six (43%). Deep tumour invasion was present in two (14%) both patients with primary NHL, the extent and volume of this tumour invasion was small and involved the prevertebral muscles (n=2), parapharyngeal fat space (n=1) and skull base Primary NHL more commonly spreads superficially to involve the nasal cavity or oropharynx, lymphadenopathy is frequent and extensive. A large tumour that fills the nasopharynx, with no or minimal invasion into deep structures, and a propensity to extend down into the tonsil, rather than up into the skull base, may suggest the diagnosis of NHL over nasopharyngeal carcinoma.     

Evolving role of F-FDG-PET/CT for the body tumor and metastases in pediatrics

¹⁸F-FDG-positron emission tomography-computerized tomography (¹⁸F-FDG-PET/CT) scan is an important imaging tool which may provide both functional and anatomical information in a single diagnostic test. It has the potential to be a valuable tool in the noninvasive evaluation and monitoring of pediatric tumors including the metastases because ¹⁸fluorodeoxyglucose (¹⁸F-FDG) is a glucose analogue that concentrates in areas of active metabolic activity. This review provides an update on functional and metabolic imaging approaches for assessment and management of the body tumor and metastases in pediatrics using a combined whole body ¹⁸F-FDG-PET/CT scanners. We discuss the benefits include improved pediatric patients’ outcome facilitated by staging and monitoring of disease and better treatment planning. It is worth to concern the preparation of children undergoing PET studies and radiation dosimetry and its implications for family and caregivers. It is important to consider the normal distribution of ¹⁸FDG in children, common variations of the normal distribution. We show some of our cases that most tumors in children accumulate and retain FDG, allowing high-quality images of their distribution and pathophysiology either at the primary site as well as in the areas of metastatic disease.