Imaging in Child Abuse and Its Techniques

Introduction:

Child abuse, also called child maltreatment, is the rejection or maltreatment of a child through physical, sexual, or psychological means by their parents or caretaker. Child abuse is classified into neglect, emotional abuse, sexual abuse, and physical abuse. Physical child abuse is also called nonaccidental injury (NAI).

What Are the Imaging Techniques Required in Child Abuse?

Child abuse is classified as:

• Skeletal injury.

• Intracranial injury.

• Thoracolumbar injury.

1. Skeletal Injury:

Injury to long bones is a more common bone injury in child abuse. Other common injuries are posterior rib fractures, classic metaphyseal lesions (CML), skull fractures, humeral fractures, and injury to the scapula, sternum, and spine. Fractures of ischiopubic rami are commonly associated with sexual abuse. In 0 to 24 months old infants, child abuse is evaluated by a skeletal survey and follow-up skeletal survey after two weeks. Child abuse is assessed in children more than two years old by skeletal survey and radiographic examination of individual sight of injury as per clinical history.

• Classic Metaphyseal Lesions: Paul Kleinman gave the term classic metaphyseal lesions (CML). This fracture is commonly observed in children less than two years old as they are small enough to shake and cannot protect their limbs. CML shows bucket handle appearance in X-rays. This fracture is most commonly found in the lower extremities, often in the knees. This fracture is about 50 percent of child abuse cases.

• Plain Radiograph - CML appears as a radiolucent area within the symphyseal metaphysis and is perpendicular to the long axis of the bone. This fracture can be either complete or partial.

• Nuclear Medicine - In nuclear medicine, the fractured site showed increased uptake of technetium- 99m methylene diphosphonate. Increased uptake of radioactive substances indicates metaphyseal fracture.

• Rib Fracture: Rib fractures in children are challenging to locate on radiographic images. Rib fractures are mostly incomplete, superimposed by surrounding structures, and are often non-displaced. Rib fractures are most commonly occurring in the posterior and lateral aspects of the ribs. Sometimes occurs in bilateral and multiple ribs also. This fracture becomes more visible with their healing due to callus and subperiosteal new bone formation in X-rays. Hence suspected rib fractures in child abuse require a follow-up skeleton survey after two weeks. Oblique chest X-rays are often advised to detect rib fractures in child abuse.

• Scapular Fracture: Scapular fracture is less common in children and is highly specific for child abuse at the acromion. For example, while shaking an infant, there might be a stretching of deltoid muscles that results in the avulsion of the acromion.

• Spinal Fracture: A spinal fracture is rare in children. This fracture occurs through hyperflexion and hyperextension mechanisms. When the child is thrown against a hard surface with their spine perpendicular to the surface, there might be compression of the vertebral body (most often thoracolumbar junction). Spinal fracture in child abuse appears as a Hangman's fracture bilateral fracture of C2 (pars interarticularis) and subluxation of C2 over C3 (third cervical vertebrae)].

• Skull Fracture: Skull fracture accounts for about 8 to 13 percent of fractures and is about one-third of skeletal fractures in abused children below two years. It appears as linear lucent areas with sharp margins. For the detection of skull fractures, skull radiography is preferred over CT (computed tomography) as the skull fractures are roughly parallel to the orientation that might be missed on CT. In addition, it requires four series of X-rays at different views.

• AP (anteroposterior).

• Both lateral.

• Towne view.

• Stairway Falls: Head injury is the most common in stairway falls. However, there might be mild to moderate injury associated with stairway falls as the initial fall has a moderate impact, followed by low-impact falls.

2. Intracranial Injury:

Intracranial injuries in child abuse can be evaluated with cranial CT and magnetic resonance imaging (MRI). Ultrasonography is also helpful in revealing intracranial abnormalities, but it fails to evaluate the intracranial injury fully. Therefore, CT is the key diagnostic tool in evaluating shaken baby syndrome. Sometimes, skull injury is associated with intracranial hemorrhage in 30 percent of abused children, as the skull of young children is thinner.

Intracranial hemorrhages are extradural hemorrhages, subdural hematomas, and subarachnoid hemorrhages.

• When there is a direct blow to the head, there might be damage to the skull with rupture of the meningeal vessels outside the dura mater resulting in extradural hemorrhages.

• During shaking, the head of the child may be thrown violently back and forth, causing subdural hematomas by damage to the veins crossing the space between the dura and the arachnoid mater. Subdural hematomas appear as crescent-shaped in CT.

• When there is massive damage to the head, there might be damage to the blood vessels over the surface of the brain resulting in subarachnoid hemorrhage.

• Cerebral parenchymal injuries are common in children but are difficult to visualize under a CT scan. MRI produces detailed signs of cerebral parenchymal injuries such as swelling and blood leakage in axonal injury.

3. Thoracoabdominal Injury:

Thoracolumbar injury can be visualized with the help of the following imaging techniques:

• Helical contrast-enhanced CT of thorax and abdomen.

• Ultrasonography of abdomen (follow-up).

• Upper gastrointestinal series.

• The liver is the most commonly injured abdominal organ in child abuse.

• Pancreatic injury results in pancreatitis, vomiting, fever, and increased serum amylase. CT is considered superior in the detection of pancreatitis and pseudocyst. Pancreatitis associated with abdominal injury in child abuse causes the spread of intramedullary bone necrosis. The pancreatic transaction can also be observed in CT.

• The duodenum and proximal jejunum of the small intestine are commonly affected during an abdominal injury in child abuse. Patients with bowel injury hematoma present with vomiting and pain. Hematoma on CT appears as highly attenuated masses. Ultrasonography shows hematoma as a hyperechoic area, and it later becomes hypoechoic.

• Bowel perforation may show intraperitoneal air in plain radiographs and CT.

• Pneumothorax, pleural effusion, hemothorax, lung contusion, and a cardiac laceration are also associated with child abuse.

Conclusion:

The radiologist should differentiate long bone injury from other medical conditions, determine the possible causes of injury, and estimate the age of the injury in child abuse. CT scan is the standard choice of imaging for abused children with a head injury. The skeletal survey on child abuse requires at least 21 X-ray images. Follow-up skeletal images should be done 10 to 14 days after the initial skeletal survey. CT or MRI should be performed earlier, three to five days after injury, when the clinical neurological signs are present.