Imaging in Child Abuse
Caffey’s landmark article of 1946 noted an association between healing long-bone fractures and chronic subdural hematomas in infancy, and it was the first to draw attention to physical abuse as a unifying etiology.  In 1962, Caffey and Kempe et al proposed manhandling and violent shaking as mechanisms of injury and emphasized the acute and long-term sequelae of abuse as serious public health problems.  Since these early reports, investigators have more clearly defined the pathophysiology of abusive injuries (see the images below). Community-service and law-enforcement authorities have taken a role in protecting potential victims and in prosecuting perpetrators.
In the United States, in 2015, there were 683,000 victims of child abuse, and approximately 1670 children died of abuse and neglect, a rate of 2.25 per 100,000 children. Almost 75% of those deaths occurred in children younger than 3 years. Most reports of abuse were submitted by educational personnel (18.4%) and legal and law enforcement personnel (18.2%). Approximatley 9% of reports were submitted by medical personnel. 
For infants and children younger than 2 years, a skeletal survey should be performed as the initial screening examination when child abuse is being considered. [4, 5, 6, 7] The survey consists of the acquisition of a series of images collimated to each body region.  The series includes frontal and lateral views of the skull, frontal and lateral views of the spine, frontal views of the chest (ribs) and pelvis, and frontal views of the extremities, including the hands and feet. [9, 10]
The skeletal survey is widely available and inexpensive in comparison with alternative imaging modalities. Other important advantages of the skeletal survey include a high sensitivity for most acute and healing fractures and a relatively low radiation burden. 
A babygram, in which the entire skeleton is depicted on a single image, is not an appropriate substitute for a properly performed survey. Geometric distortion and varying exposures are unacceptable limitations of this image. Use of a high-detail, high-contrast, screen-film system with good spatial resolution is mandatory. All abnormal areas should be viewed on at least 2 projections.
Computed tomography (CT) scanning of the head is the imaging modality of choice for evaluating a child with acute neurologic findings or retinal hemorrhage on physical examination. It is more sensitive to acute intracerebral and extra-axial hemorrhages than is magnetic resonance imaging (MRI). Brain MRI may be helpful as an adjunct for the evaluation of axonal shear injuries and for a precise dating of intracranial hemorrhage. [12, 13]
Subarachnoid hemorrhages (SAHs) are best demonstrated on CT scans. The use of MRI to detect acute SAH remains controversial. However, MRI is superior to CT scanning for differentiating a hypoattenuating subdural hematoma from cerebrospinal fluid (CSF) and for detecting small and chronic extra-axial fluid collections. (See the images below; both images reveal a subdural hematoma, the first with a CT scan and the second with an MRI scan.)
(See the images below.)
Classic metaphyseal lesion (CML), as represented by a corner fracture of the lateral aspect of the humeral metaphysis.
Most child abuse–related injuries are readily detectable during imaging. Radiologic examination is the mainstay for diagnosing physical abuse in children. [14, 15, 16] Careful correlation of the observed radiologic findings with the proposed mechanism of injury and with the child’s clinical status is imperative in the evaluation of any child in whom abuse is suspected. If such correlation is not performed, important clues of an inflicted injury may be overlooked, and the child may be returned to an abusive environment—with potentially disastrous consequences. [17, 18, 19, 20]
The radiologist has important medical and legal roles in cases of child abuse. The radiologist may be the first to raise a question of abuse if characteristic or unexplained findings are encountered during imaging. Immediate, direct communication with the referring physician is imperative in such cases.
A radiologist’s testimony regarding findings of possible abuse may be required, and the radiologist may be asked to give an opinion as to the likely age of the child’s fractures and about the possibility of alternative diagnoses. Familiarity with radiographic patterns and mechanisms of abuse generally allows the radiologist to give an interpretation with a high degree of certainty.
Because imaging studies document occult injuries, they may justify the implementation of protective measures when the patient’s clinical presentation suggests abuse.
Kleinman et al reported the utility of high-detail, postmortem radiography in identifying skeletal injuries that had otherwise been overlooked. 
Skeletal injury is the most common form of injury (excluding external soft-tissue injuries) in child abuse. Fractures are documented in 11-55% of physically abused children. 
ACR Appropriateness Criteria
The appropriate imaging of pediatric patients being evaluated for suspected physical abuse depends on the age of the child, the presence of neurologic signs and symptoms, and evidence of visceral thoracic or abdominopelvic injuries.
A skeletal survey is indicated in the initial imaging evaluation of children 24 mo of age or younger. In
older children, it is usually appropriate to target imaging to the area(s) of suspected injury.
Skeletal survey and CT of the head without contrast are indicated in the emergent/initial imaging evaluation of a child with neurologic signs and symptoms, complex skull fracture, apnea, multiple fractures, spine trauma, or facial injury. These examinations are not indicated for general screening.
MRI of the head may provide additional diagnostic information to head CT in about 25% of children.
MRI of the cervical spine should be considered at the time of head MRI, because unsuspected injury (usually ligamentous) may be present in over 33% of children with intracranial injury.
Skeletal survey and CT of the chest/abdomen/pelvis with IV contrast are indicated if there are signs or symptoms of intrathoracic or intra-abdominal visceral injury (eg, abdominal pain/distention/bruising, abnormal liver, or pancreatic enzymes).
In children 24 mo of age or younger with equivocal skeletal survey or with a high clinical suspicion for abuse and a negative initial skeletal survey, a repeat limited/focused skeletal survey performed at 2 wk may add diagnostic information.
The resulting fracture may cross the diaphysis in an oblique or transverse plane, or it may create the highly specific and classic metaphyseal lesion (CML). The classic metaphyseal lesion is also referred to as a corner fracture or a bucket-handle fracture. A CML occurs when a torsional force is applied to the immature primary spongiosa adjacent to a cartilaginous growth plate.
Rib fractures occur when a compressive force is applied simultaneously to the sternum and to the costovertebral junction during violent shaking as the perpetrator compresses the child’s chest using both hands. 
The posterior ribs are most commonly fractured, because the greatest force is imparted to the articulation of the head and to the neck of the rib with the transverse process of the vertebral body.
However, fractures are not limited to the posterior aspects of the ribs. Anterolateral fractures are also common. Rib fractures are typically noted at several contiguous levels; they are frequently bilateral.
(See the image below.)
Head injury accounts for 80% of deaths associated with abuse in children younger than age 2 years. Mechanisms of injury include forceful shaking, either by itself or accompanied by abrupt impact. [12, 13, 25, 26] (See the images below.)
In an acute setting, CT scanning is more readily available and more cost-effective than MRI. MRI is used as a problem-solving modality when CT findings are unexplained or confusing.
CT scanning of the abdomen is indicated if abdominal injury is suspected. CT scanning demonstrates visceral injuries and retroperitoneal hematomas.
Gastrografin upper-GI study under fluoroscopic guidance is occasionally indicated for evaluating submucosal hemorrhages of the duodenum or for identifying perforation of the duodenum.
Skeletal scintigraphy may be used when clinical suspicion remains high despite normal findings on a skeletal survey.  Advantages of scintigraphy include increased sensitivity for acute posterior rib fractures, because the spine tends to obscure these injuries on radiographic examination. Fractures of the spine may be better depicted with scintigraphy than with radiography.
Limitations of techniques
Fractures that are parallel or nearly parallel to the section orientation may be missed during CT scanning. Therefore, radiography of the skull is preferred over CT scanning for examining these injuries.
The disadvantages of scintigraphy include diminished sensitivity in detecting skull fractures and CMLs, as these are contiguous with the normal isotope-avid growth plates. In addition, because all abnormal sites must be confirmed radiographically, an osseous survey is the preferred initial examination.
Scintigraphy is also limited because of its expense, lack of availability, amount of gonadal radiation exposure relative to plain radiography, and lack of reader expertise.
Evan Geller MD, Bernard Coombs MB, ChB, PhD, David Levey MD, Eugene Lin MD, Beverly Wood MD MSEd PhD, Avneesh Chhabra MD, Eleanor Smergel MD | March 23, 2017 | https://emedicine.medscape.com/article/407144-overview