Acute Fractures and Dislocations of the Ankle and Foot in Children.

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. The online slide presentation from the RSNA Annual Meeting is available for this article. ©RSNA, 2020.

Ultrasound with Doppler evaluation of congenital hepatic vascular shunts.

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.

Caudal cell mass developmental aberrations: an imaging approach.

The objective of this review is to describe antenatal and postnatal imaging criteria, which allow diagnosis and aid workup, prognostication and treatment of developmental anomalies of the caudal cell mass. The lower spinal cord (conus medullaris), filum terminale and inferior lumbar and sacral nerve roots develop from the caudal cell mass, a remnant of the embryologic primitive streak composed of undifferentiated pluripotential cells. Anomalous caudal cell mass development can manifest as tight filum terminale, caudal dysgenesis, terminal myelocystocele, anterior sacral meningocele or sacrococcygeal teratoma. Lower spinal cord development occurs simultaneously and in topological proximity to the developing lower gastrointestinal and genitourinary tracts, leading to coexistent malformations. We review the embryology of the caudal cell mass, describe the role of antenatal and postnatal imaging for diagnosing, staging, prognosticating and guiding intranatal or postnatal intervention for developmental anomalies of this region and briefly discuss clinical manifestations and treatment goals and strategies. An overview of antenatal imaging diagnosis of associated multisystem abnormalities will be provided where applicable.

Malformed vertebrae: a clinical and imaging review.

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.

Systematic radiographic evaluation of tibial hemimelia with orthopedic implications.

Tibial hemimelia is a rare lower-extremity pre-axial longitudinal deficiency characterized by complete or partial absence of the tibia. The reported incidence is 1 in 1 million live births. In this pictorial essay, we define tibial hemimelia and describe associated conditions and principles of preoperative imaging assessment for a child with tibial hemimelia. We also indicate the imaging findings that might influence the choice of treatment, describe the most widely used classification systems, and briefly discuss current treatment approaches.

Pediatric distal forearm and wrist injury: an imaging review.

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.