Pediatric Radiology

In the pediatric population, imaging often plays a critical diagnostic role, especially in diagnosing congenital anomalies. In children, CT scans are avoided if at all possible due to the high risk of radiation exposure. In addition, both CT and (especially) MRI require children to hold still for significant periods of time and often require sedation to complete the study. For these reasons, plain radiography (often with contrast), fluoroscopy, and ultrasound are the imaging modalities of choice for most suspected cases involving GI pathology. Some conditions that can be diagnosed using imaging include hypertrophic pyloric stenosis, necrotizing enterocolitis, midgut malrotation with or without volvulus, intestinal atresia intussusception, appendicitis, Hirschsprung disease, mesenteric lymphadenitis, and obstructions of the biliary tree.

Chest abnormalities are a common presenting pathology of the pediatric population. Imaging modalities such as chest X-rays are the initial diagnostic test of choice used in urgent/emergent pediatric cases. Imaging modalities aid in differentiating the causes of respiratory distress in infants and finding the underlying infectious, traumatic, or congenital disorder. Computed tomography (CT) is a useful adjunctive modality in the pediatric population when conventional radiography fails to adequately characterize pathology. Given the common occurrence with many cardiac or vascular anomalies, specific protocols are necessary to highlight potentially abnormal anatomical structures. Pediatric chest imaging is a multimodality process at most centers used to help answer clinical questions and adequately care for individuals.

The apophysis is a secondary ossification center found on non-weight-bearing segments of bones. The apophysis is also the site of ligament or tendon insertion and is involved in the peripheral growth of the bone. These secondary growth centers are generally open in late childhood and may not close until early adulthood. With overuse, the apophysis may become inflamed and painful, becoming vulnerable to tearing and avulsion. An acute apophyseal avulsion fracture occurs when a portion of the apophysis is pulled off by the ligament, usually secondary to explosive movements and eccentric muscular contractions. Apophyseal avulsion fractures are primarily treated conservatively, but may require surgical repair if the avulsed fragment is large or significantly displaced.

The bones of growing children exhibit unique characteristics, which, combined with the unique mechanisms of injury seen in children, result in fracture patterns differing significantly from those common in adults. The greenstick fracture is an incomplete fracture usually seen in long bones. The bone is typically bent, and the fracture extends only partway through the bone. Greenstick fractures are at high risk for refracture and should be completely immobilized. Greenstick fractures rarely require reduction but should be managed cautiously to prevent malunion or angulation deformities. A patient with a greenstick fracture should be referred for orthopedic follow-up.

A “toddler’s fracture” is a spiral or oblique fracture of the distal tibia in toddlers resulting from a low-energy trauma with a rotational/twisting component. These fractures are often seen in children who are learning to walk and who do not have a specific history of trauma. The child can sometimes present with a painful limp or refusal to bear weight on the affected limb. Management comprises analgesia and immobilizing the injured leg for several weeks.

The bones of growing children exhibit unique characteristics. These characteristics, combined with the unique mechanisms of injury seen in children, result in fracture patterns that differ significantly from those that are common in adults. When axial loads are applied, particularly to long bones in children, compressive forces may result in buckling of the bone without disruption of the periosteum. These fractures are called buckle or torus fractures and are considered generally stable, requiring only immobilization.

Supracondylar fractures are the most common elbow fractures in the pediatric population. The most common mechanism of injury involves a fall on an outstretched hand, resulting in a fracture of the distal humerus. Patients frequently present with pain, visible deformity, and limited range of motion of the injured elbow. This fracture often requires immediate orthopedic consultation secondary to the displacement of the fracture and the frequency of concomitant neurovascular injury.