Tests
1st tests to order
cranial CT
Test
CT remains the imaging modality of choice and is superior to MRI for detecting skull fracture in both pediatric and adult patients.[35][36][37]
All patients with features suggestive of a skull fracture (e.g., Battle sign, periorbital ecchymoses, rhinorrhea, or otorrhea) should have cranial CT. Basilar skull fractures are the most difficult to detect; CT scans should be performed with thin cuts, and should include 3D reconstruction of some type.[38][39][40][41] However, as skull fractures often present with no clinical symptoms or signs on physical exam but are significant risk factors for intracranial pathology, the question of whom to scan is very important. Evaluation criteria to guide imaging include the New Orleans Criteria, the Canadian CT head rule, and the American College of Radiology Appropriateness Criteria®, and UK National Institute for Health and Care Excellence (NICE) criteria.[28][29][30][37] The yield of fracture detection is increased if more than one radiologist reviews the images.[40]
Result
detects skull fractures and any associated intracranial pathology
Tests to consider
MRI
Test
While CT is considered the first-line imaging modality for suspected intracranial injury, MRI is useful when there are persistent neurologic deficits that remain unexplained after CT, especially in the subacute or chronic phase or in the absence of trauma history.[37]
The main benefit of MRI is increased detection of associated intracranial pathology such as diffuse axonal injury not seen on CT scan. MRI can increase detection of intracranial hemorrhage (extradural/subdural) by up to 30%.[4][35][39][42] MRI may therefore be considered if there is continuing concern of intracranial pathology, in the absence of CT findings.
MRI (alone or in conjunction with angiography) may also be useful if the fracture involves major vascular structures (e.g., the carotid canal or superior sagittal sinus), to assess underlying vascular injury/pathology.[37][39][43][44][45]
Result
detects skull fractures and any associated intracranial pathology
MR angiography
beta-2 transferrin assay
Test
For any patient with head trauma and otorrhea/rhinorrhea, an immunoassay (beta-2 transferrin assay) of the suspect fluid can stain positive in the presence of the protein.
The test should be performed if clear or blood-tinged drainage is present from the nose or ears.
If positive, it indicates cerebrospinal fluid (CSF) leakage and is reliable even in the presence of blood or mucus. It has a sensitivity of nearly 100% and a specificity of 95%.[55]
Result
positive if CSF leak
cranial ultrasound
Test
May be a useful adjunct to a CT head following confirmation of a fracture in the pediatric population, to detect dural tears, brain herniation, or a growing skull fracture.[37] There may also be a role for ultrasound to screen for skull fractures in pediatric patients with minor head trauma.[48][49][50]
Result
may show dural tears or brain herniation
plain skull x-ray
Test
Inferior to CT scanning and no longer recommended as a first-line investigation. However, it may be used as an interim aid if CT scanning is not available.
Result
may reveal fracture
skeletal survey
Test
Should be considered if child abuse is suspected.[51][52]
The skeletal survey should be composed of frontal and lateral views of the skull, lateral views of the cervical spine and thoracolumbosacral spine, and single frontal views of the long bones, hands, feet, chest, and abdomen. Oblique views of the ribs should be obtained to increase the accuracy of diagnosing rib fractures, which may be the only skeletal manifestation of abuse.[51] A repeat limited skeletal survey after 2 weeks can detect additional fractures and can provide fracture dating information.[51] Repeat skeletal survey should be performed when abnormal or equivocal findings are found on the initial study and when abuse is suspected on clinical grounds.[51][53] To limit radiation exposure, pelvis, spine, and skull radiographs can be omitted if no injury was initially seen in these regions.[51]
Result
variable; unexplained fractures including skull fractures, long-bone fractures, rib fractures, and classic metaphyseal lesions
CT angiogram
Test
Should be considered if there is any suspicion for vascular injury, such as when the fracture involves the carotid canal or overlies a vessel (e.g., middle meningeal artery, sagittal sinus).[37]
Result
may detect any associated vascular injury/pathology
CT venogram
Test
From an imaging standpoint, the most important risk factor for traumatic venous injury is a skull fracture (or less commonly a penetrating foreign body) that involves a dural venous sinus or jugular bulb or foramen).[37] In the acute setting, CT venogram is the most useful study in the imaging evaluation of suspected intracranial venous injury.[37][54]
Result
may reveal acute dural venous sinus thrombosis
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