A laryngeal fracture is an injury to one of the components of the laryngeal apparatus. These include injuries to the hyoid bone, thyroid cartilage, or cricoid cartilage. These injuries are best evaluated with a CT of the neck. Although contrast is not necessary to evaluate laryngeal injury, CECT and/or CTA is preferred for penetrating trauma. Cartilage fracture may appear as a step-off of the normally smooth contour of the cartilage. Signs of cartilage dislocation include abnormal rotation of the arytenoids cartilage and widening at the articulations. Indirect signs include submucosal edema, hematoma, and airway narrowing. Presence of extra-luminal air suggests injury to the larynx and/or esophagus.
Laryngeal fracture is more commonly caused by blunt than penetrating trauma. Assess the patient’s ability to phonate, listen for the presence of stridor, and palpate for tenderness in the anterior neck. If the patient is stable, flexible laryngoscopy is performed (along with CT) to determine the extent of the injury. Patients in need of emergent airway management may be difficult or impossible to intubate via the oral route, and cricothyrotomy may be impossible depending on the level of injury. In severe cases, emergent tracheotomy may be the only way to secure the patient’s airway.
Blunt trauma force sufficient to cause a laryngeal fracture often results in other injuries to the vasculature, spine, and/or esophagus. Consider CT angiography (CTA) of the neck to exclude arterial injury in patients with laryngeal fracture.
Findings of laryngeal injury may be subtle. Always review the cervical spine CT in bone and soft tissue windows when looking for these injuries as the amount of calcification within the cartilage may vary.
Penetrating arterial injury is the disruption of the vessel wall by a foreign body entering the neck such as with a gunshot wound or knife injury. CTA has largely replaced conventional angiography and/or surgical neck exploration in excluding injury to the major arteries and veins of the neck. CTA findings include neck hematoma, extravasation of contrast, dissection, and pseudoaneurysm formation. A pseudoaneurysm is a saccular defect of the arterial wall where an indwelling hematoma is contained only by the adventitia of the arterial wall as opposed to a true aneurysm, where an intact arterial wall is maintained. Pseudoaneurysms are significantly more likely to rupture due to their weak architecture.
Expanding hematoma, change in phonation, and stridor after penetrating neck injury should prompt definitive airway management, and typically occur prior to the radiographic identification of a carotid artery injury. Absence of these clinical findings may allow the angiographic evaluation prior to definitive airway management.
CTA of the neck has replaced surgical exploration of penetrating neck injuries.
The most common vascular injuries are dissection, hematoma, and pseudoaneurysm.
Figure 3.2 ▪ Penetrating Vascular Injury.
A: Axial CTA shows intimal dissection flap in the right internal carotid artery (arrow) of a 95-year-old male with a gunshot wound. B: Dissection and Pseudoaneurysm. Sagittal CTA shows the dissection and pseudoaneurysm of the ICA (arrow). Metallic debris from a gunshot wound project over the skull base.
Dissection is the disruption of the intima of the vessel wall with blood tracking between the intima and media of the wall, creating an “intimal flap.” CTA is the test of choice to evaluate for carotid artery dissection. CT angiographic findings of traumatic carotid artery dissection include an intimal flap separating the true and false lumens, a narrowed and irregular vessel lumen, thickened vessel wall due to intramural hematoma, and cone-like tapering of the vessel lumen.
A fat-suppressed axial T1-weighted sequence does an excellent job in demonstrating subacute blood products within the vessel wall. Subacute blood products are hyperintense (bright) on T1-weighted images due to the presence of methemoglobin. MR angiography findings are similar to CTA. Conventional angiography remains the gold standard if CTA or MRI/MRA is equivocal.
Carotid artery dissection may be spontaneous or occur in the setting of blunt trauma. Missed carotid artery dissection will likely progress to stroke. Clinical features that should prompt evaluation for carotid artery dissection include neck hematoma, ipsilateral seat-belt ecchymosis, head, neck, or face pain, partial Horner’s syndrome, TIA, and stroke-like symptoms. Minor trauma such as overhead painting or chiropractic manipulation may precipitate a carotid artery dissection.
Cervical spine fractures should raise the clinical suspicion for carotid artery dissection after major trauma.
An axial fat-saturated T1-weighted sequence is routinely used to evaluate for carotid dissection.
CTA of the neck is nearly 100% sensitive and specific for the evaluation of carotid artery dissection when compared to arterial angiography.
Figure 3.3 ▪ Traumatic Carotid Artery Dissection.
A: Sagittal CTA shows abrupt occlusion of the right ICA (arrow) following a car accident in a 19-year-old female. B: Coronal CTA shows abrupt occlusion of the right ICA (arrow). C: AP view of common carotid artery injection angiogram shows severe narrowing of the proximal ICA (arrows). D: AP view of common carotid angiogram following placement of stent in ICA shows thrombus in M1 segment of middle cerebral artery (arrow) subsequently treated with intra-arterial tPA and MERCI retrieval device (thrombus present initially due to dissection).
Ludwig’s angina is a severe infection involving the sublingual, submandibular, and submental spaces causing induration and elevation of the tongue. Most cases are odontogenic in origin. Contrast-enhanced neck CT demonstrates a phlegmon with inflammation beneath the tongue, and may also show the presence of an abscess (fluid collection with contrast enhancing rim) or spread of the infection to the mediastinum.
Ludwig’s angina is diagnosed clinically, and confirmed with CECT. The greatest immediate threat to life is airway obstruction. Preparation should be made for immediate nasal fiberoptic intubation in case of decompensation. Oral intubation or cricothyrotomy may be impossible due to swelling and landmark distortion. Clues that a patient needs a secure airway prior to imaging include respiratory distress, air hunger, and an inability to tolerate laying flat. Many cases require operative drainage, though improvement with medical management alone is also possible.
Tracheal disruption is a rare injury, which includes tears of the connective tissue and fractures of the tracheal cartilage. CXR and CT findings of tracheal disruption include extensive subcutaneous emphysema, bilateral pneumothoraces, and pneumomediastinum. Other findings include an abnormally superior position of the hyoid bone (above the 3rd cervical vertebra) or penetration of the trachea by the distal end of an endotracheal tube.
Most patients with this injury will die in the pre-hospital setting as airway management is often extremely challenging. In cases of disruption due to penetrating trauma, it may be possible to intubate the trachea distal to the injury through laceration. In cases caused by blunt trauma, the injury may be able to be bridged using fiberoptic intubation techniques. If this is impossible, tracheostomy will be required. These injuries often require operative repair; however, if the defect can be bridged and the air leak halted, expectant management is possible.
A peritonsillar abscess (PTA) is a collection of pus located between the palatine tonsillar capsule and the pharyngeal muscles. CECT of the neck is the preferred method for imaging PTA. PTA appears as a fluid collection with a rim of contrast enhancement in the tonsillar fossa. Narrowing and contralateral displacement of the airway is seen to varying degrees. Peritonsillar cellulitis or phlegmon may have a similar clinical appearance, but will lack a well defined abscess collection (though sometimes an early abscess can be difficult to distinguish from a phlegmon). Other CT findings include obscuration of the adjacent parapharyngeal fat. Bedside ultrasound can rapidly confirm the presence of PTA. An endocavitary transducer is placed gently within the mouth and the symptomatic side scanned in both the sagittal and tranverse planes. The abscess will appear as a hypoechoic structure. This technique allows for the precise localization of the abscess and the internal carotid artery.
The diagnosis of a PTA is primarily clinical. Confirmation with imaging is not necessary in most cases. Clinical findings include unilateral sore throat, trismus, swelling of the tonsillar pillar, and deviation of the uvula. Definitive treatment of a PTA is ED drainage (often needle aspiration is sufficient) combined with antibiotics. A CT or ultrasound can confirm the presence or abscence of fluid and avoid an unnecessary procedure. Obtain a CT in cases where the patient is immunosuppressed, appears extremely toxic, or if there is concern for spread of the infection to the deep neck spaces and/or mediastinum.
Figure 3.7 ▪ Tonsillar Abscess.
A: Axial CECT shows a rim-enhancing fluid collection in the right tonsillar fossa (arrow). There is some inflammation in the right parapharyngeal fat. B: Coronal CECT shows a rim-enhancing fluid collection in the right tonsillar fossa (arrow). C: Intraoral ultrasound performed at the bedside demonstrates two hypoechoic regions within a swollen tonsil representing a tonsillar abscess. Depth measurements can be made for needle entry. The distance to the ipsilateral carotid artery can be determined as well.
A retropharyngeal abscess (RPA) is a collection of pus in the retropharyngeal space due to trauma or extension of a parapharyngeal infection. Contrast-enhanced neck CT of an RPA typically demonstrates a dark fluid collection distending the retropharyngeal space posterior to the oropharynx with or without a contrast-enhancing rim. Differentiation from suppurative retropharyngeal lymphadenitis can be difficult, but lymph nodes tend to be located off-midline. An early abscess or retropharyngeal phlegmon may not demonstrate rim enhancement. CT is very sensitive for RPA and alternative diagnoses. Traditionally, soft tissue lateral neck radiographs have been used to evaluate for abnormal swelling in the prevertebral/retropharyngeal tissues (>7 mm at C2 and >14 mm at C6 in children and > 22 mm at C6 in adults). Detection of gas within the prevertebral soft tissues is highly suggestive, but rarely seen. As expiration and neck flexion can both spuriously thicken the prevertebral soft tissues, the specificity is low. Optimal technique is crucial, including true lateral positioning, and obtaining the radiograph during inspiration and neck extension.
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