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Childhood interstitial lung disease (chILD) refers to a diverse group of rare diffuse parenchymal lung diseases affecting infants and children, previously associated with considerable diagnostic confusion due to a lack of information regarding their clinical, imaging, and histopathologic features. Due to improved lung biopsy techniques, established pathologic diagnostic criteria, and a new structured classification system, there has been substantial improvement in the understanding of chILD over the past several years. The main purpose of this article is to review the latest advances in the imaging evaluation of pediatric interstitial lung disease within the framework of the new classification system.

Trauma to the pediatric spine can manifest as osseous, disco-ligamentous, and/or neurological injuries. Associated mortality is significantly higher than in adults. Injury patterns in children are distinct from those encountered in adults. Although spine radiographs are the first line of diagnosis, they may be challenging to interpret in children due to the difficulty of applying recognized radiographic landmarks to the partially ossified spine. Ligamentous laxity and developmental phenomena also lead to imaging pitfalls. Much of the recent literature on this subject focuses on region-specific injuries or individual entities, and may not be tailored specifically to the radiologist, thereby not stressing key aspects pertinent to the effective performance and successful interpretation of imaging exams. We aim to address this void. We provide a comprehensive review of pediatric spine trauma, outlining the clinical decision tools, imaging protocols including the current American College of Radiology (ACR) appropriateness guidelines, interpretive pitfalls and tips to navigate these pitfalls, and management implications of the spectrum of these injuries. Throughout the text, extensive tables, illustrations and imaging examples reinforce key concepts.

Pediatric musculoskeletal infections often pose a diagnostic challenge due to their frequently vague and nonspecific clinical presentation. Imaging evaluation is a crucial component to diagnostic workup of these entities. Changed epidemiology of these infections over the past 2 decades has resulted in increases in both disease incidence and severity in the pediatric population. Prompt and accurate diagnosis is essential in order to reduce the risk of morbid sequelae, and to optimize patient management. In this article, the unique pathophysiology of musculoskeletal infections and characteristic imaging findings in children compared with adults are reviewed.

Malignant primary bone tumors are uncommon in the pediatric population, accounting for 3%-5% of all pediatric malignancies. Osteosarcoma and Ewing sarcoma comprise 90% of malignant primary bone tumors in children and adolescents. This paper provides consensus-based recommendations for imaging in children with osteosarcoma and Ewing sarcoma at diagnosis, during therapy, and after therapy.

Pediatric soft tissue tumors of the extremity include rhabdomyosarcoma and nonrhabdomyosarcoma neoplasms. This manuscript provides consensus-based imaging recommendations for imaging evaluation at diagnosis, during treatment, and following completion of therapy for patients with a soft tissue tumor of the extremity.

The expanded use of Magnetic Resonance Imaging (MRI) for evaluation of musculoskeletal pathology in infants has resulted in increased sensitivity and specificity of diagnostic evaluation. The unique anatomic, physiologic and behavioral attributes of the infant however, present challenges in MR imaging. Adjustments to MRI hardware, scan technique and protocols can help circumvent several of these challenges. While sedation and anesthesia can ensure immobilization, they have some inherent side effects. Accelerated and abbreviated MRI protocols with judicious use of gadolinium-based contrast can limit the need for sedation/anesthesia. In this article, we overview musculoskeletal MRI in infants, emphasizing technical optimization and safety.

As access to MRI in pediatrics increases, the radiologist needs to become acquainted with the basic principles of MRI safety. As part of the image acquisition, the static magnetic field, gradient system, and the radiofrequency transmit-receive coil interact with medical and non-medical implants and can result in serious injury. The main stage of risk triage is based on the determination of whether the implant is MRI-safe, conditional, unsafe or unknown. Guiding principles include the strict adherence to manufacturer specifications for MRI-conditional implants and the assumption that an unknown implant is MR-unsafe. In this article we review considerations for common medical implants encountered in pediatrics including ventriculoperitoneal shunts, orthopedic hardware, orthodontic hardware, pacemakers, vascular stents, vagal nerve stimulators and cochlear implants. Finally, we review a set of high-yield considerations, including the non-communicative patient (sedated or non-verbal), susceptibility artifacts from unclear source, and the approach to an unknown implant.

Diffusion-weighted MRI, or DWI, is a fast, quantitative technique that is easily integrated into a morphological MR acquisition. The ability of DWI to aid in detecting multifocal skeletal pathology and in characterizing tissue cellularity to a level beyond that possible with other techniques makes it a niche component of multiparametric MR imaging of the skeleton. Besides its role in disease detection and establishing cellularity and character of osseous lesions, DWI continues to be examined as a surrogate biomarker for therapeutic response of several childhood bone tumors. There is increasing interest in harnessing DWI as a potential substitute to alternative modes of imaging evaluation that involve radiation or administration of intravenous contrast agent or radiopharmaceuticals, for example in early detection and diagnosis of capital femoral epiphyseal ischemia in cases of Legg-Calvé-Perthes disease, or diagnosis and staging of lymphoma. The expected evolution of skeletal diffusivity characteristics with maturation and the unique disease processes that affect the pediatric skeleton necessitate a pediatric-specific discussion. In this article, the author examines the developmentally appropriate normal appearances, technique, artifacts and pitfalls of pediatric skeletal DWI.

Contrast-enhanced CT angiography (CTA) is a widely used, noninvasive imaging technique for evaluating cardiovascular structures. Contrast-induced nephrotoxicity is a concern in renal disease; however, the true nephrotoxic potential of iodinated contrast media (CM) is unknown. If a renal impaired patient requires CTA, it is important to protect the kidneys from further harm by reducing total iodinated CM volume while still obtaining diagnostic quality imaging. These same reduced volume CM techniques can also be applied to nonrenal impaired patients in times of CM shortage. This educational review discusses several modifications to CTA that can be adapted to both conventional 64-slice and the newer generation CT scanners which enable subsecond acquisition with a reduced CM volume technique. Such modifications include hardware and software adjustments and changes to both the volume and flow rate of administered CM, with the goal to reduce the dose of CM without compromising diagnostic yield.

Congenital, developmental, and acquired conditions of the pediatric hip frequently present with sequelae in the adult. There is substantial overlap in the end-stage results of these pathologic conditions, including osseous changes, chondral/labral injuries, and premature osteoarthritis. This review discusses the top 10 etiopathogeneses of pediatric hip conditions and presents associated dysmorphisms in the adult on an illustrative, multimodality, case-based template. Quantitative imaging metrics and the role of advanced imaging techniques are reviewed. The ultimate goal is enhanced understanding of the expected evolution of childhood hip pathologic conditions and their associated complications for general radiologists.

Distinct biologic and mechanical attributes of the pediatric skeleton translate into fracture patterns, complications, and treatment dilemmas that differ from those of adults. In children, increasing participation in competitive sports activities has led to an increased incidence of acute injuries that affect the foot and ankle. These injuries represent approximately 13% of all pediatric osseous injuries. Important posttraumatic complications include premature physeal arrest, three-dimensional deformities and consequent articular incongruity, compartment syndrome, and infection. The authors describe normal developmental phenomena and injury mechanisms of the ankle and foot and associated imaging findings; mimics and complications of acute fractures; and dislocations that affect the pediatric ankle and foot. Treatment strategies, whether conservative or surgical, are aimed at restoring articular congruency and functional alignment and, for pediatric patients specifically, protecting the physis. The different types of ankle and foot fractures are described, and the American College of Radiology guidelines used to determine appropriate imaging recommendations for patients who meet the Ottawa ankle and foot rules are discussed. The systems used to classify clinically important fractures, including the Salter-Harris, Dias-Tachdjian, Rapariz, and Hawkins systems, are described, with illustrations that reinforce key concepts. These classification systems aid in diagnosis and treatment planning, facilitate communication, and help standardize documentation and research. This information is intended to supplement radiologists' understanding of developmental phenomena, anatomic variants, fracture patterns, and associated complications that affect the pediatric foot and ankle. In addition, the role of imaging in ensuring appropriate treatment, follow-up, and patient and parent counseling is highlighted.

Congenital chest lesions encompass several important entities. Without prompt intervention, many of these can culminate in serious complications. Timely and accurate radiologic interpretation of these entities is integral to patient management. Imaging can help characterize and prognosticate several of these entities, and may both suggest the need for and guide therapy. We overview the clinical presentation, associated complications, imaging characteristics, and prognostic indicators-both postnatal and antenatal-of the spectrum of emergently presenting congenital chest lesions. We also outline current and evolving management strategies, whether fetal, peripartum, or postnatal. The ultimate goal is to help radiologists formulate timely and effective diagnoses of these entities and boost the relevance of their input towards clinical decision-making.

Pediatric musculoskeletal infections often pose a diagnostic challenge due to their frequently vague and nonspecific clinical presentation. Imaging evaluation is a crucial component to diagnostic workup of these entities. Changed epidemiology of these infections over the past 2 decades has resulted in increases in both disease incidence and severity in the pediatric population. Prompt and accurate diagnosis is essential in order to reduce the risk of morbid sequelae, and to optimize patient management. In this article, the unique pathophysiology of musculoskeletal infections and characteristic imaging findings in children compared with adults are reviewed.

Cervical teratomas are a rare form of fetal teratoma that can grow to massive size. Generally, these masses can be surgically excised after birth with excellent physical and functional prognosis because the benign variants respect anatomical borders. The primary complications of these masses are associated with compromise of the trachea and esophagus: upper airway obstruction and polyhydramnios. We report the first documented occurrence of superior vena cava syndrome and hypoxic ischemic encephalopathy associated with a massive, right-sided cervical teratoma. This case highlights that when cervical teratomas are right-sided and sufficiently large, they can extend inferiorly and compromise central venous return to the heart. This unique presentation would likely have required fetal surgical excision to avoid catastrophic cerebral injury.

Acquired diaphragmatic defects occur secondary to trauma, infection, surgery or neoplasm. These defects can lead to abnormal thoraco-abdominal fistulous communications also. Examples of surgically created diaphragmatic defects are omental, colonic interposition and vascular grafts. Regardless of etiology, these transdiaphragmatic communications provide a direct path for spread of pathology between the abdomen and thorax. If left untreated and unrecognized, these fistulae portend a high morbidity and mortality. Subtle but important diagnostic clues can be present on imaging. This pictorial essay describes commonly encountered imaging findings seen with acquired transdiaphragmatic communications. This knowledge will improve diagnostic confidence of the interpreting radiologist in acute situations and confounding clinical scenarios.

The fetal circulation is characterized by the presence of three physiological vascular shunts - the ductus arteriosus, the foramen ovale and the ductus venosus. Acting in concert, these shunts preferentially stream blood flow in a pattern that maximizes efficiency of blood oxygenation by the maternofetal unit. Shortly following the transition to extrauterine life, a quick and predetermined succession of events results in closure of these embryological structures with consequent establishment of postnatal vascular flow patterns. While this transition is often seamless, the physiological shunts of the fetus occasionally fail to regress. Such failure to regress can occur in isolation or in association with other congenital malformations. This failed regression challenges the circulatory physiology of the neonate and might have implications for the optimum functioning of several organ systems. When symptomatic, these shunts are treated. Interventions, when undertaken, might be medical, endovascular or surgical. The radiologist's role continues to expand in the assessment of these shunts, in providing a roadmap for treatment and in prompt identification of treatment-related complications. This review is to familiarize radiologists with the embryology, pre- and post-treatment imaging appearances, and associated complications of persistent fetal vascular shunts.

Diffusion-weighted imaging (DWI) complements the more established T1, fluid-sensitive and gadolinium-enhanced magnetic resonance pulse sequences used to assess several pediatric skeletal pathologies. There is optimism that the technique might not just be complementary but could serve as an alternative to gadolinium and radiopharmaceuticals for several indications. As a non-contrast, free-breathing and noninvasive technique, DWI is especially valuable in children and is readily incorporated into existing MRI protocols. The indications for skeletal DWI in children include distinguishing between benign and malignant skeletal processes, initial assessment and treatment response assessment for osseous sarcomas, and assessment of inflammatory arthropathies and femoral head ischemia, among others. A notable challenge of diffusion MRI is the dynamic nature of the growing pediatric skeleton. It is important to consider the child's age when placing DWI findings in context with potential marrow pathology. This review article summarizes the current and evolving applications of DWI for assessing the pediatric skeleton, rounding off the discussion with evolving directions for further research in this realm.

As access to MRI in pediatrics increases, the radiologist needs to become acquainted with the basic principles of MRI safety. As part of the image acquisition, the static magnetic field, gradient system, and the radiofrequency transmit-receive coil interact with medical and non-medical implants and can result in serious injury. The main stage of risk triage is based on the determination of whether the implant is MRI-safe, conditional, unsafe or unknown. Guiding principles include the strict adherence to manufacturer specifications for MRI-conditional implants and the assumption that an unknown implant is MR-unsafe. In this article we review considerations for common medical implants encountered in pediatrics including ventriculoperitoneal shunts, orthopedic hardware, orthodontic hardware, pacemakers, vascular stents, vagal nerve stimulators and cochlear implants. Finally, we review a set of high-yield considerations, including the non-communicative patient (sedated or non-verbal), susceptibility artifacts from unclear source, and the approach to an unknown implant.

A variety of structural developmental anomalies affect the vertebral column. Malformed vertebrae can arise secondary to errors of vertebral formation, fusion and/or segmentation and developmental variation. Malformations can be simple with little or no clinical consequence, or complex with serious structural and neurologic implications. These anomalies can occasionally mimic acute trauma (bipartite atlas versus Jefferson fracture, butterfly vertebra versus burst fracture), or predispose the affected individual to myelopathy. Accurate imaging interpretation of vertebral malformations requires knowledge of ageappropriate normal, variant and abnormal vertebral morphology and the clinical implications of each entity. This knowledge will improve diagnostic confidence in acute situations and confounding clinical scenarios. This review article seeks to familiarize the reader with the embryology, normal and variant anatomy of the vertebral column and the imaging appearance and clinical impact of the spectrum of vertebral malformations arising as a consequence of disordered embryological development. Teaching points • Some vertebral malformations predispose the affected individual to trauma or myelopathy. • On imaging, malformed vertebrae can be indistinguishable from acute trauma. • Abnormalities in spinal cord development may be associated and must be searched for. • Accurate interpretation requires knowledge of normal, variant and abnormal vertebral morphology.

This study aimed to identify findings on non-ECG-gated CT pulmonary angiography (CTPA) indicating decreased left ventricle (LV) systolic function, later confirmed by echocardiogram.After obtaining institutional review board approval, review was performed of emergency department (ED) patients who had CTPA and follow-up echocardiogram within 48 h, over 18 months. Patients with pulmonary embolus, suboptimal CTPA, arrhythmias or pericardial tamponade were excluded. One hundred thirty-seven patients were identified and divided into cases (LVEF40%, n = 52) and controls (LVEF50%, n = 85). Two reviewers performed these analyses: measurement of enhancement in main pulmonary artery (MPA), LV, and aorta; subjective enhancement of LV and aorta (Ao) relative to MPA using a four-point Likert scale; contrast transit time (TD) to trigger CTPA and LV shortlong axis dimensions. When available, the most recent N-terminal pro-B-type natriuretic peptide (NT-proBNP) level was recorded.Decreased aortic and LV subjective enhancement were the best predictors of LV systolic dysfunction. For Ao/MPA ratio, an optimal cutoff value of 0.20 resulted in a sensitivity of 0.54 and specificity of 0.93 (AUC = 0.83, 0.78-0.88 95% CI). A threshold of 86.7 HU for Ao enhancement resulted in a sensitivity of 0.68 and specificity of 0.90 (AUC = 0.82, 0.77-0.88 95% CI). A LV short axis diameter of more than 54.3 mm had a sensitivity of 0.62 and specificity of 0.98 (AUC = 0.88, 0.83-0.92 95% CI). For the LV long axis diameter, a cutoff of 87.5 mm resulted in a sensitivity of 0.66 and specificity of 0.84 (AUC = 0.78, 0.72-0.84 95% CI). With bolus timing, cases had a longer TD (13.4 vs. 10.4 s, p 0.0001).Unsuspected LV systolic dysfunction can be recognized on a CTPA by identification of decreased aortic enhancement, LV enlargement and increased TD. This has important diagnostic implications for the patient presenting with shortness of breath, chest pain, or dyspnea.

Contrast flow and enhancement patterns seen on thoracic CT angiography (CTA) can often be challenging and may often reveal more than is immediately apparent. A non-diagnostic CTA following the initial contrast injection can be secondary to many causes; these include both extrinsic factors, such as injection technique/equipment failure (iv cannula, power injector), and intrinsic, patient-related factors. Contrast pressure and flow graphs often contain useful information regarding the etiology of a non-diagnostic scan. Understanding these graphs will help the radiologist plan a repeat contrast injection to overcome the deficiencies of the first injection and thus obtain a diagnostic scan. The current review article outlines normal and abnormal intravenous contrast dynamics, discusses how to recognize etiologies of non-diagnostic scans, and ultimately addresses techniques to overcome obstacles towards obtaining normal contrast opacification of the target vessel. In addition, there are some life-threatening findings, which unless sought for, may remain hidden in plain sight. Key Points • Using contrast enhancement and flow patterns to identify the cause of a non-diagnostic CTA. • Recognize life threatening causes of altered contrast dynamics such as cardiac asystole. • Non-target vessel opacification may hold key to underlying pathophysiology. Electronic supplementary material The online version of this article (doi:10.1007/s13244-016-0524-3) contains supplementary material, which is available to authorized users.

Lesions involving the outer cortical surface of the bone occur quite often among children. Broadly, these include benign cortical, juxtacortical and periarticular lesions, dysplasias affecting the cortical bone, regional and diffuse periosteal pathology and malignant tumours. Some of these lesions are unique to the paediatric population; others are more frequently seen among children than adults — yet others have an adult predilection but can occasionally be seen in children. A complete list of differential considerations for lesions involving the outer cortical surface of the bone in children is presented. Imaging characteristics on plain film radiography and MR are described in association with multiple examples and illustrations. A pictorial review detailing the imaging features of surface lesions of the bone in children will be a useful aide for both radiologists and their clinical colleagues, and will help them sort their way through the maze of differential diagnoses for these abnormalities. Teaching Points • Surface lesions of bones in children comprise a distinct entity and differ from those in adults. • Imaging plays an important role towards classifying surface lesions of bones in children. • MRI features may be characteristic and aid precise diagnosis, thus guiding further management.

Evaluation for pneumothorax is an important indication for obtaining chest radiographs in patients who have had trauma, recent cardiothoracic surgery or are on ventilator support. By definition, a persistent pneumothorax constitutes ongoing bubbling of air from an in situ chest drain, 48 h after its insertion. Persistent pneumothorax remains a diagnostic dilemma and identification of potentially treatable aetiologies is important. These may be chest tube related (kinks or malposition), lung parenchymal disease, bronchopleural fistula, or rarely, oesophageal-pleural fistula. Although radiographs remain the mainstay for diagnosis and follow up of pneumothorax, computed tomography (CT) is increasingly being used for problem solving. Aetiology of persistent air leak determines the optimal treatment. For some, a simple repositioning of the chest tube/drain may suffice; others may require surgery. In this pictorial review, we will briefly describe the physiology of pneumothorax, discuss imaging features of identifiable causes for persistent pneumothorax and provide a brief overview of treatment options. Specific aetiology of a persistent air leak may often not be immediately discernible, and will need to be carefully sought. Accurate interpretation of imaging studies can expedite diagnosis and facilitate prompt treatment. Key points • Persistent pneumothorax is defined as a leak persisting for more than 2 days. • Radiographs can identify chest-tube-related causes of pneumothorax. • CT is the most useful test to identify other causes. • Penetrating thoracic injury can cause fistulous communication resulting in a persistent pneumothorax. • Discontinuity of visceral pleura identified by CT may indicate a bronchopleural fistula.

We report the imaging appearances of a case of pathologically proven, neonatal neuroblastoma 4S with diffuse hepatic metastatic involvement at presentation. Patient had an abnormal appearing liver both by ultrasound and MR. There was no evidence for associated adrenal tumor by imaging. Lack of an associated adrenal mass led to initial misinterpretation of diffuse hepatic accumulation of MIBG seen with radionuclide scintigraphy. To the best our knowledge, this is the first report of metastatic neonatal 4S neuroblastoma without an adrenal (or extra-adrenal) primary identified either on pre- or post-natal imaging.

Mediastinal and paracardiac lesions are usually first diagnosed on a chest radiograph or echocardiogram. Often, a computed tomography is obtained to further delineate these lesions. CT may be suboptimal for evaluation of enhancement characteristics and direct extension into the adjacent mediastinal structures. With its intrinsic superior soft-tissue characterization, magnetic resonance imaging (MRI) can better delineate these lesions, their internal tissue characteristics, and identify adhesion/invasion into adjacent structures. This pictorial essay provides a brief synopsis of the key MRI sequences and their utility in further characterizing mediastinal and paracardiac lesions.

Congenital aberrant hepatic vascular communications result from intrahepatic or extrahepatic errors in vascular development or involution during the transition from fetal to newborn hepatic circulation. These hepatic vascular shunts can be fortuitously discovered and asymptomatic, or can cause symptoms of varying severity, often presenting diagnostic dilemmas. Some hepatic vascular shunts resolve spontaneously while others require interventional radiologic or surgical closure. Affected patients are often first studied with real-time and Doppler ultrasound, so radiologists should familiarize themselves with the expected ultrasound findings of these vascular shunts for effective diagnosis, triage and management. In this review, the authors focus on ultrasound and Doppler findings of hepatic vascular shunts with underlying embryology, clinical features and management strategies. Broadly, these aberrant hepatic vascular communications include portosystemic venous shunts (which can be intra- or extrahepatic and include persistent patent ductus venosus), arterioportal, arteriovenous or mixed shunts.

Acute limp in a child presents a diagnostic conundrum and can result from a variety of causes. The underlying etiology is often referable to the hip, but the spine, abdomen, pelvis, or knee can be alternatively implicated. An adequate clinical history and satisfactory physical examination are often difficult in younger children. Consequently, there is disproportionate reliance on imaging to arrive at the correct diagnosis. The potential for rapid clinical deterioration and long-term sequelae is a risk with some of the conditions presenting with acute hip (septic hip, osteomyelitis). This review article describes the imaging appearance of common etiologies for acute limp in the ambulatory preschool (1–5 years) and school-age child (5–12 years). The ultimate goal is to familiarize the interpreting radiologist with the imaging appearance of specific clinical entities that lead to acute limp while providing a readily accessible resource on how to image the patient most appropriately and judiciously.

Physeal injuries occurring secondary to neonatal birth-related trauma are rare entities. Most reported cases of physeal injury involve the distal humerus with only a few published case reports of proximal femoral involvement. So far, we have found only one reported case of neonatal distal femoral epiphysiolysis following Caesarean section. We hereby report a unique case of distal femoral physeal injury with at least partial epiphyseal separation following an uneventful, spontaneous vaginal delivery. Given the uneventful delivery and no known prenatal risk factors, the imaging findings were initially not recognized as being secondary to birth-related injury. Nonaccidental trauma and infection were considered among the possible etiologies for the clinical and imaging findings and a detailed workup for both these entities was performed. Distal femoral physeal injury was considered as a diagnosis of exclusion only after both initial differential considerations were excluded. The authors hope that a knowledge of this entity will facilitate a more accurate differential in cases of thigh swelling and hypomobility in the newborn.

The ribs are frequently affected by blunt or penetrating injury to the thorax. In the emergency department setting, it is vital for the interpreting radiologist to not only identify the presence of rib injuries but also alert the clinician about organ-specific injury, specific traumatic patterns, and acute rib trauma complications that require emergent attention. Rib injuries can be separated into specific morphologic fracture patterns that include stress, buckle, nondisplaced, displaced, segmental, and pathologic fractures. Specific attention is also required for flail chest and for fractures due to pediatric nonaccidental trauma. Rib fractures are associated with significant morbidity and mortality, both of which increase as the number of fractured ribs increases. Key complications associated with rib fracture include pain, hemothorax, pneumothorax, extrapleural hematoma, pulmonary contusion, pulmonary laceration, acute vascular injury, and abdominal solid-organ injury. Congenital anomalies, including supernumerary or accessory ribs, vestigial anterior ribs, bifid ribs, and synostoses, are common and should not be confused with traumatic pathologic conditions. Nontraumatic mimics of traumatic rib injury, with or without fracture, include metastatic disease, primary osseous neoplasms (osteosarcoma, chondrosarcoma, Ewing sarcoma, Langerhans cell histiocytosis, and osteochondroma), fibrous dysplasia, and Paget disease. Principles of management include supportive and procedural methods of alleviating pain, treating complications, and stabilizing posttraumatic deformity. By recognizing and accurately reporting the imaging findings, the radiologist will add value to the care of patients with thoracic trauma. Online supplemental material is available for this article. ©RSNA, 2017.

Congenital and acquired disorders of the accessory organs of digestion are encountered relatively commonly when imaging infants and young children. This chapter reviews the relevant embryology, anatomy and imaging findings of the spectrum of pathology affecting these organs.

Pediatric ear, nose, and throat emergencies broadly comprise infection, trauma, and airway obstruction secondary to a multitude of etiologies. Imaging occupies center stage in the diagnosis of many of these conditions and their complications, making it imperative for radiologists and other physicians covering the pediatric emergency department to familiarize themselves with the imaging appearances of these entities. Toward this goal, this article describes the imaging features of common pediatric ear, nose, and throat emergencies. Differential considerations, potential fallacies, and complications have been discussed when appropriate. Because a sound knowledge of the most relevant, efficient, time, and cost-effective imaging modality is of undisputable value in the acute setting, the preferred modality for each specific condition has been outlined. Finally, in alignment with our commitment to using radiation judiciously, we have suggested using ultrasonography and magnetic resonance instead of computed tomography, where possible, to optimize cost-benefit ratio for our young patients.

Injuries to the pediatric distal forearm and wrist have myriad manifestations. Growth plate injuries can occur in the skeletally immature child. An unfused growth plate is less robust than ligamentous complexes and therefore is more easily injured. The Salter-Harris fracture classification system is used to grade physeal injuries based on their imaging appearance. This grading has prognostic significance: higher grades imply an increased likelihood of eventual growth disturbance. A disrupted distal radioulnar joint characterizes Galeazzi-type injuries at all ages; however, before skeletal maturity is attained, a disrupted radioulnar joint can manifest as a distal ulnar physeal separation with associated epiphysiolysis of the distal ulna, termed a Galeazzi-equivalent fracture. Bone contusions can be diagnosed using fluid-sensitive fat-suppressed magnetic resonance imaging, and their detection can alter the prognosis. The unique cartilaginous cushion of the developing bony carpus imparts resilience to fracture and dislocation until carpal maturity is reached. Chronic compressive forces to the wrist in a skeletally immature gymnast can result in a distinct pattern of bone and soft-tissue injury referred to as gymnast wrist. If the distal radial physis fuses prematurely, ulnar growth will outpace radial growth, leading to positive ulnar variance and consequent chronic wrist pain from ulnar impaction.

Background Pulmonary arteries are not just affected by thrombus. Congenital and acquired conditions can also involve the pulmonary arteries. An awareness of these conditions is important for the radiologist interpreting chest computed tomography (CT). Methods The anatomy of the pulmonary arteries was reviewed. CT and magnetic resonance (MR) acquisition protocols for imaging the pulmonary arteries were discussed. The imaging appearances of congenital and acquired anomalies involving the pulmonary arteries, using CT and other modalities, were presented. Results Imaging features of congenital anomalies presented include pulmonary agenesis, partial pulmonary artery agenesis, patent ductus arteriosus, pulmonary artery sling, congenital pulmonary artery stenosis and coronary to pulmonary artery fistula. Acquired pulmonary artery anomalies discussed include arteritis, infected aneurysm and sarcoma. Pulmonary artery filling defects besides thromboembolism are also discussed, including foreign body emboli. Imaging features of bronchogenic carcinoma and mediastinal fibrosis demonstrating compression of the pulmonary arteries are presented, followed by a brief discussion of post repair appearance of the pulmonary arteries for congenital heart disease. Conclusions Congenital and acquired pulmonary artery anomalies have a characteristic appearance on a variety of imaging modalities. An acquaintance with the imaging features of these anomalies is needed to avoid misinterpretation and reach the correct diagnosis. Teaching Points • Discuss a variety of congenital and acquired anomalies of the pulmonary arteries. • Discuss the imaging appearance of the presented congenital or acquired pulmonary artery anomalies. • Describe CT and MR acquisition protocols for imaging the pulmonary arteries. • Review the anatomy of the pulmonary arteries.

OBJECTIVE. The thalami are subject to multiple insults including metabolic and toxic phenomena, acute demyelination, infection, infarction, hemorrhage and neoplastic involvement. The purpose of this article is to review the neuroimaging approach, classification, and imaging of bilateral thalamic lesions with histopathology correlation and application of advanced techniques. CONCLUSION. Neuroimaging of abnormal pediatric thalami uses conventional MRI sequences and advanced techniques to characterize lesions. Although there is considerable imaging overlap, a tailored approach can facilitate diagnosis and management.

Medication neurotoxicity may have a variety of imaging manifestations in children. In this pictorial essay, we review the two most common brain injury patterns, posterior reversible encephalopathy syndrome (PRES) and acute toxic leukoencephalopathy (ATL). Proposed etiologies, salient features on neurological imaging, and methods for differentiating these entities and their implications will be discussed. Certain agents do not fall into these two broad patterns but instead characteristically involve central structures. We individually review several medications and their respective neurotoxic appearances including methotrexate, cyclosporine A, tacrolimus, metronidazole and vigabatrin. Diagnosis of medication neurotoxicity may be achieved by the combination of new-onset neurological deficits, recent initiation of a new therapy agent and distinctive findings on magnetic resonance imaging. Clinical and radiological improvement and/or resolution are frequently observed after the agent is discontinued.

Staging of gynecologic malignancies is essential for proper management; it is important to ensure that the appropriate imaging examinations are performed to ensure the most accurate staging possible. Accurate staging is very crucial for these patients because the treatment plan and prognosis depend primarily upon the staging at the time of initial diagnosis. Many women are understaged on clinical conventional staging examination, even by experienced gynecologic oncologists, because of location of the metastatic disease (eg, under the hemidiaphragm) or because of the small size of tumor deposits. This article will describe the types of imaging examinations that are available for staging, their diagnostic capabilities, proper use, as well as their inherent limitations.

Transcatheter Aortic Valve Implantation (TAVI) is increasingly being used in patients with severe aortic stenosis who are not candidates for surgery. ECG-gated CT angiography (CTA) plays an important role in the preoperative planning for these devices. As the number of patients undergoing these procedures increases, a subset of patients is being recognized who have contraindications to iodinated contrast medium, either due to a prior severe allergic type reaction or poor renal function. Another subgroup of patients with low flow and low gradient aortic stenosis is being recognized that are usually assessed for severity of aortic stenosis by stress echocardiography. There are contraindications to stress echocardiography and some of these patients may not be able to undergo this test. Non-contrast MRI can be a useful emerging modality for evaluating these patients. In this article, we discuss the emerging indications of non-contrast MRI in preoperative assessment for TAVI and describe the commonly used MRI sequences. A comparison of the most important measurements obtained for TAVI assessment on CTA and MRI from same subjects is included. Teaching Points • MRI can be used for preoperative assessment of aortic annulus. • MRI is an alternate to CTA when iodinated contrast is contraindicated. • Measurements obtained by non-contrast MRI are similar to contrast enhanced CTA. • MRI can be used to assess severity of aortic stenosis. Electronic supplementary material The online version of this article (doi:10.1007/s13244-016-0470-0) contains supplementary material, which is available to authorized users.