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Thymic Imaging Pitfalls and Strategies for Optimized Diagnosis. Radiographics : a review publication of the Radiological Society of North America, Inc Thymic imaging is challenging because the imaging appearance of a variety of benign and malignant thymic conditions are similar. CT is the most commonly used modality for mediastinal imaging, while MRI and fluorine 18 fluorodeoxyglucose (FDG) PET/CT are helpful when they are tailored to the correct indication. Each of these imaging modalities has limitations and technical pitfalls that may lead to an incorrect diagnosis and mismanagement. CT may not be sufficient for the characterization of cystic thymic processes and differentiation between thymic hyperplasia and thymic tumors. MRI can be used to overcome these limitations but is subject to other potential pitfalls such as an equivocal decrease in signal intensity at chemical shift imaging, size limitations, unusual signal intensity for cysts, subtraction artifacts, pseudonodularity on T2-weighted MR images, early imaging misinterpretation, flow and spatial resolution issues hampering assessment of local invasion, and the overlap of apparent diffusion coefficients between malignant and benign thymic entities. FDG PET/CT is not routinely indicated due to some overlap in FDG uptake between thymomas and benign thymic processes. However, it is useful for staging and follow-up of aggressive tumors (eg, thymic carcinoma), particularly for detection of occult metastatic disease. Pitfalls in imaging after treatment of thymic malignancies relate to technical challenges such as postthymectomy sternotomy streak metal artifacts, differentiation of postsurgical thymic bed changes from tumor recurrence, or human error with typical "blind spots" for identification of metastatic disease. Understanding these pitfalls enables appropriate selection of imaging modalities, improves diagnostic accuracy, and guides patient treatment. RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. 10.1148/rg.230091
Multimodality imaging appearance of intrapericardial paragangliomas. Clinical radiology Paragangliomas are neuroendocrine tumours of the sympathetic and parasympathetic nervous systems originating from neural crest cells. Less than 1% of paragangliomas in the heart originate from intrinsic cardiac ganglia cells in the posterior wall of the atria, atrioventricular groove, and along the root of the great vessels. We describe the tumour characteristics, patient demographics, presentation, means of diagnosis, pathology correlation, management, and outcome in 11 patients with intrapericardial paragangliomas. To the authors' knowledge, this is the largest case series reported, with emphasis on multimodality imaging findings. 10.1016/j.crad.2022.08.131
Multimodality Imaging of Cardiac Paragangliomas. Radiology. Cardiothoracic imaging Paragangliomas are rare neuroendocrine tumors of extra-adrenal autonomic paraganglia origin. Paragangliomas rarely involve the heart, and they account for less than 1% of primary cardiac tumors. Most cardiac paragangliomas are incidentally detected at echocardiography or CT or during the workup of symptomatic patients with high catecholamine levels. Paragangliomas are typically located around the great vessels, coronary arteries (atrioventricular groove), or the atria, which can be explained by the tumor origin from the paraganglia and the distribution of the cardiac plexus. At MRI, cardiac paragangliomas typically have low to intermediate signal on T1-weighted images and high signal on T2-weighted images. The tumors are strongly vascularized, with high uptake on first-pass perfusion images and a heterogeneous pattern on late gadolinium enhancement images. Functional imaging is indicated for diagnostic confirmation and to screen for additional tumor locations or metastatic disease. Surgical excision is the only curative treatment. Cardiac CT angiography or invasive angiography should be performed preoperatively to precisely delineate tumor vascularization. In particular, its relation with the coronary arteries should be determined, as paragangliomas can be perfused by the coronary arteries, posing additional surgical challenges and the need for coronary revascularization. This imaging essay reviews the characteristics of paragangliomas and the use of multimodality imaging for diagnosis and treatment. CT Angiography, Molecular Imaging, MR Imaging, PET/CT, Cardiac, Heart, Neoplasms-Primary © RSNA, 2023. 10.1148/ryct.230049
MR Lymphangiography in Lymphatic Disorders: Clinical Applications, Institutional Experience, and Practice Development. Radiographics : a review publication of the Radiological Society of North America, Inc Lymphatic flow and anatomy can be challenging to study, owing to variable lymphatic anatomy in patients with diverse primary or secondary lymphatic pathologic conditions and the fact that lymphatic imaging is rarely performed in healthy individuals. The primary components of the lymphatic system outside the head and neck are the peripheral, retroperitoneal, mesenteric, hepatic, and pulmonary lymphatic systems and the thoracic duct. Multiple techniques have been developed for imaging components of the lymphatic system over the past century, with trade-offs in spatial, temporal, and contrast resolution; invasiveness; exposure to ionizing radiation; and the ability to obtain information on dynamic lymphatic flow. More recently, dynamic contrast-enhanced (DCE) MR lymphangiography (MRL) has emerged as a valuable tool for imaging both lymphatic flow and anatomy in a variety of congenital and acquired primary or secondary lymphatic disorders. The authors provide a brief overview of lymphatic physiology, anatomy, and imaging techniques. Next, an overview of DCE MRL and the development of an MRL practice and workflow in a hybrid interventional MRI suite incorporating cart-based in-room US is provided, with an emphasis on multidisciplinary collaboration. The spectrum of congenital and acquired lymphatic disorders encountered early in an MRL practice is provided, with emphasis on the diversity of imaging findings and how DCE MRL can aid in diagnosis and treatment of these patients. Methods such as DCE MRL for assessing the hepatic and mesenteric lymphatic systems and emerging technologies that may further expand DCE MRL use such as three-dimensional printing are introduced. RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. 10.1148/rg.230075
A review of the role of MRI in diagnosis and treatment of early stage lung cancer. Clinical and translational radiation oncology Despite magnetic resonance imaging (MRI) being a mainstay in the oncologic care for many disease sites, it has not routinely been used in early lung cancer diagnosis, staging, and treatment. While MRI provides improved soft tissue contrast compared to computed tomography (CT), an advantage in multiple organs, the physical properties of the lungs and mediastinum create unique challenges for lung MRI. Although multi-detector CT remains the gold standard for lung imaging, advances in MRI technology have led to its increased clinical relevance in evaluating early stage lung cancer. Even though positron emission tomography is used more frequently in this context, functional MR imaging, including diffusion-weighted MRI and dynamic contrast-enhanced MRI, are emerging as useful modalities for both diagnosis and evaluation of treatment response for lung cancer. In parallel with these advances, the development of combined MRI and linear accelerator devices (MR-linacs), has spurred the integration of MRI into radiation treatment delivery in the form of MR-guided radiotherapy (MRgRT). Despite challenges for MRgRT in early stage lung cancer radiotherapy, early data utilizing MR-linacs shows potential for the treatment of early lung cancer. In both diagnosis and treatment, MRI is a promising modality for imaging early lung cancer. 10.1016/j.ctro.2020.06.002
The role of radiological imaging for masses in the prevascular mediastinum in clinical practice. Prosch Helmut,Röhrich Sebastian,Tekin Zeynep Nilufer,Ebner Lukas Journal of thoracic disease Tumors in the prevascular compartment of the mediastinum are rare and imaging plays a major role in their detection, (differential) diagnosis, staging, and follow-up. The prevascular compartment is bordered anteriorly by the posterior aspect of the sternum, posteriorly by the ventral aspect of the pericardium, cranially by the thoracic outlet, and caudally by the diaphragm. In many cases, the diagnosis of a lesion in the prevascular compartment is an incidental finding either on chest radiograph (CR) or on computed tomography (CT) scans. The differential diagnosis of masses in the pre-vascular mediastinum include primarily tumors arising from the thymus or the thyroid gland, lymphomas and germ cell tumors. The differential diagnosis of mediastinal masses is primarily based on the location of the mass, its tissue composition (i.e., fat content, calcifications) and the age of the patient. The imaging method of choice is CT, as it combines a high spatial and temporal resolution with the ability to determine tissue composition and detect fluid components, as well as areas of fat and calcifications. MRI is used as a more specific problem-solving tool to discriminate solid lesions from cystic lesions or to provide evidence of minimal fat content in teratoma and thymic rebound. The role of PET/CT in the evaluation of tumors other than lymphomas in the prevascular compartment is still under discussion. 10.21037/jtd-20-964
The diagnostic value of magnetic resonance imaging compared to computed tomography in the evaluation of fat-containing thoracic lesions. The British journal of radiology Intrathoracic fat-containing lesions may arise in the mediastinum, lungs, pleura, or chest wall. While CT can be helpful in the detection and diagnosis of these lesions, it can only do so if the lesions contain scopic fat. Furthermore, because CT cannot demonstrate microscopic or intravoxel fat, it can fail to identify and diagnose microscopic fat-containing lesions. MRI, employing spectral and chemical shift fat suppression techniques, can identify both macroscopic and microscopic fat, with resultant enhanced capability to diagnose these intrathoracic lesions non-invasively and without ionizing radiation. This paper aims to review the CT and MRI findings of fat-containing lesions of the chest and describes the fat-suppression techniques utilized in their assessment. 10.1259/bjr.20220235
Pictorial Review of Mediastinal Masses with an Emphasis on Magnetic Resonance Imaging. Park Jin Wang,Jeong Won Gi,Lee Jong Eun,Lee Hyo Jae,Ki So Yeon,Lee Byung Chan,Kim Hyoung Ook,Kim Seul Kee,Heo Suk Hee,Lim Hyo Soon,Shin Sang Soo,Yoon Woong,Jeong Yong Yeon,Kim Yun Hyeon Korean journal of radiology Magnetic resonance imaging (MRI) has become a crucial tool for evaluating mediastinal masses considering that several lesions that appear indeterminate on computed tomography and radiography can be differentiated on MRI. Using a three-compartment model to localize the mass and employing a basic knowledge of MRI, radiologists can easily diagnose mediastinal masses. Here, we review the use of MRI in evaluating mediastinal masses and present the images of various mediastinal masses categorized using the International Thymic Malignancy Interest Group's three-compartment classification system. These masses include thymic hyperplasia, thymic cyst, pericardial cyst, thymoma, mediastinal hemangioma, lymphoma, mature teratoma, bronchogenic cyst, esophageal duplication cyst, mediastinal thyroid carcinoma originating from ectopic thyroid tissue, mediastinal liposarcoma, mediastinal pancreatic pseudocyst, neurogenic tumor, meningocele, and plasmacytoma. 10.3348/kjr.2019.0897
Imaging modalities (MRI, CT, PET/CT), indications, differential diagnosis and imaging characteristics of cystic mediastinal masses: a review. Mediastinum (Hong Kong, China) Cystic mediastinal masses have traditionally represented a diagnostic dilemma with differentiation of malignant masses a particular area of concern. Each imaging modality has strengths and weaknesses in mediastinal imaging-computed tomography (CT) offers increased spatial resolution at the cost of poorer soft tissue differentiation and requiring ionizing radiation, while magnetic resonance imaging (MRI) offers superior soft tissue contrast/characterization at significantly greater cost. Ultrasound offers real-time visualization but is operator and tissue dependent. [18F]fluoro-D-glucose (F-18 FDG) positron emission tomography (F-18 FDG PET) CT provides functional information, but poorer spatial resolution. Recent advances have focused upon the use of magnetic resonance imaging to aid in characterization of cystic mediastinal lesions, particularly in the context of indeterminate CT findings. The mediastinum may be divided into three anatomic compartments: prevascular, visceral, and paravertebral. All three compartments extend superiorly from the thoracic inlet and inferiorly to the diaphragm. These compartments provide a useful framework for categorizing normal and pathologic mediastinal processes. In this article, we will review the imaging characteristics of mediastinal cystic lesions via a case-based review divided by anatomical mediastinal compartments. Characteristic imaging features and troubleshooting are particular areas of focus. Normal variants that may mimic cystic pathology are discussed. The roles of CT and MRI will be emphasized. Cases from our institution are presented as illustrative examples. 10.21037/med-22-31
Magnetic resonance imaging of the pediatric mediastinum: updates, tips and tricks. Thacker Paul G Pediatric radiology Magnetic resonance imaging (MRI) of the pediatric mediastinum is challenging for the practicing radiologist. Many confounding factors add to the complexity of pediatric mediastinal MRI including small patient size, broad spectrum of mediastinal pathologies, motion artifacts and the need for sedation in a significant portion of children. However, with special attention to motion-reduction techniques and knowledge of pediatric-specific considerations, pediatric radiologists can help to provide accurate and timely diagnosis and also prevent multimodality imaging where MRI might be all that is needed. The purpose of this paper was present a practical review of pediatric mediastinal MRI with particular emphasis on diseases where MRI is the primary imaging modality of choice. Additionally, the author addresses those mediastinal processes for which MRI serves as a secondary problem-solving imaging tool. 10.1007/s00247-021-05041-8
Radiological Imaging in Chest Diseases: Moving Away from Conventional Modes. Indian journal of pediatrics A chest radiograph is the most common and the initial radiological investigation for evaluating a child presenting with respiratory complaints. However, performing and interpreting chest radiography optimally requires training and skill. With the relatively easy availability of computed tomography (CT) scanning and more recently multidetector computed tomography (MDCT), these investigations are often performed. Although these can be the cross-sectional imaging modalities of choice in certain situations where detailed and exact anatomical and etiological information is required, both these investigations are associated with increased radiation exposure which has more detrimental effects on children, especially when repeated follow-up imaging is necessary to assess the disease status. Ultrasonography (USG) and magnetic resonance imaging (MRI) have evolved as radiation-free radiological investigations for evaluating the pediatric chest pathologies over the last few years. In the present review article, the utility and the current status, as well as the limitations of USG and MRI for evaluation of pediatric chest pathologies, are discussed. Radiology has grown beyond having just the diagnostic capabilities in managing children with chest disorders in the last two decades. Image-guided therapeutic procedures (percutaneous and endovascular) are routinely performed in children with pathologies in the mediastinum and lungs. The commonly performed image-guided pediatric chest interventions, including biopsies, fine needle aspiration, drainage procedures and therapeutic endovascular procedures, are also discussed in the current review. 10.1007/s12098-023-04615-8
State-of-the-art MR Imaging for Thoracic Diseases. Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Since thoracic MR imaging was first used in a clinical setting, it has been suggested that MR imaging has limited clinical utility for thoracic diseases, especially lung diseases, in comparison with x-ray CT and positron emission tomography (PET)/CT. However, in many countries and states and for specific indications, MR imaging has recently become practicable. In addition, recently developed pulmonary MR imaging with ultra-short TE (UTE) and zero TE (ZTE) has enhanced the utility of MR imaging for thoracic diseases in routine clinical practice. Furthermore, MR imaging has been introduced as being capable of assessing pulmonary function. It should be borne in mind, however, that these applications have so far been academically and clinically used only for healthy volunteers, but not for patients with various pulmonary diseases in Japan or other countries. In 2020, the Fleischner Society published a new report, which provides consensus expert opinions regarding appropriate clinical indications of pulmonary MR imaging for not only oncologic but also pulmonary diseases. This review article presents a brief history of MR imaging for thoracic diseases regarding its technical aspects and major clinical indications in Japan 1) in terms of what is currently available, 2) promising but requiring further validation or evaluation, and 3) developments warranting research investigations in preclinical or patient studies. State-of-the-art MR imaging can non-invasively visualize lung structural and functional abnormalities without ionizing radiation and thus provide an alternative to CT. MR imaging is considered as a tool for providing unique information. Moreover, prospective, randomized, and multi-center trials should be conducted to directly compare MR imaging with conventional methods to determine whether the former has equal or superior clinical relevance. The results of these trials together with continued improvements are expected to update or modify recommendations for the use of MRI in near future. 10.2463/mrms.rev.2020-0184
Magnetic resonance imaging of the pediatric mediastinum. Bardo Dianna M E,Biyyam Deepa R,Patel Mittun C,Wong Kevin,van Tassel Dane,Robison Ryan K Pediatric radiology The mediastinum, the central anatomical space of the thorax, is divided by anatomical landmarks but not by physical boundaries. The mediastinum is a conduit, a space through which cranial nerves, important nerve branches, the sympathetic chain, vascular structures, and visceral structures, the trachea and esophagus pass. This arrangement allows contiguous extension or communication of disease along facial planes and through potential spaces to and from the head and neck or cervical spine, to and from the superior mediastinum, between superior and inferior mediastinal levels, and between inferior mediastinal spaces into the intra- and retroperitoneal spaces. Magnetic resonance imaging (MRI) of the mediastinum in children poses technical challenges, in particular cardiac and respiratory motion, and diagnostic challenges, including a broad range of tissue types and possible diagnoses. In this paper we review mediastinal anatomy, MRI sequences and protocol choices and include a short discussion of features and MRI findings of some of the congenital and acquired pathologies that are most often encountered in the pediatric mediastinum. 10.1007/s00247-018-4112-1
Approach to Imaging of Mediastinal Masses. Diagnostics (Basel, Switzerland) Mediastinal masses present a diagnostic challenge due to their diverse etiologies. Accurate localization and internal characteristics of the mass are the two most important factors to narrow the differential diagnosis or provide a specific diagnosis. The International Thymic Malignancy Interest Group (ITMIG) classification is the standard classification system used to localize mediastinal masses. Computed tomography (CT) and magnetic resonance imaging (MRI) are the two most commonly used imaging modalities for characterization of the mediastinal masses. 10.3390/diagnostics13203171
Rare mediastinal masses - imaging review. Patnaik Sujata,Malempati Amaresh Rao,Uppin Megha,Susarla Rammurti Journal of cancer research and therapeutics Mediastinal masses span a wide histopathological and radiological spectrum. Apart from primary thymic/thyroid masses and lymphomas, all other mediastinal masses can be considered rare tumors. Chest radiography and Computed tomography (CT) are helpful to characterize the mass and can reach a diagnosis or a close differential diagnosis. MRI in special situations can depict the pericardial/vascular invasion better, and diffusion studies can recognize benign from the malignant mass. The imaging details of 15 histopathologically proven cases of rare mediastinal tumors are described. Neuroblastoma (NB) (n = 3) was the most common among the rare masses. Three were sarcomas, one liposarcoma, one synovial sarcoma, one spindle-cell tumor and one Hemangiopericytoma (HPC). Lymphoma presenting as a single mass, neuroendocrine tumor (NET) of the anterior mediastinum, paraganglioma of the posterior mediastinum (one each) were seen.The imaging features of these rare mediastinal masses have to be kept in mind for appropriate diagnosis. 10.4103/jcrt.JCRT_587_19
Anterior mediastinal lesions: CT and MRI features and differential diagnosis. Nakazono Takahiko,Yamaguchi Ken,Egashira Ryoko,Mizuguchi Masanobu,Irie Hiroyuki Japanese journal of radiology Anterior mediastinum is the most common location of mediastinal tumors, which include various solid and cystic lesions. The lesion location and CT and MRI features are important in the differential diagnosis. Recently, CT-based mediastinal compartment classification systems were proposed and suggested to be useful for accurate evaluation of mediastinal lesions. CT and MRI reflect the pathological findings of mediastinal lesions, and knowledge of the pathological features is important for the differential diagnosis. In this article, we review the CT and MRI features of anterior mediastinal lesions and describe important points in the differential diagnosis. 10.1007/s11604-020-01031-2