CT Neck for Stridor: Indications and Approach
Contrast-enhanced CT of the neck is indicated for hemodynamically stable patients with stridor when there is concern for deep neck infection, airway obstruction from mass effect, or when the etiology of stridor remains unclear after initial clinical assessment, particularly in adults and older children where direct visualization may be limited. 1
When to Order CT Neck with Contrast
Primary Indications
- Suspected deep neck space infection or inflammation where CT is superior to ultrasound for evaluating the extent of deep neck pathology and can identify dental sources of infection in febrile patients 2
- Evaluation of airway patency and aerodigestive tract integrity in the emergency setting, as the aerodigestive tract must be scrutinized for patency when evaluating acute neck symptoms 1
- Assessment of mass lesions causing airway compromise, where contrast helps distinguish vessels from lymph nodes and confirms whether masses are hypervascular 2
Technical Considerations
- Always use intravenous contrast for neck CT in stridor evaluation, as contrast accentuates abnormally enhancing phlegmonous and neoplastic tissues and delineates abscesses or necrotic areas 1
- Dual-phase imaging (with and without contrast) is not usually necessary 2
- Apply ALARA (as low as reasonably achievable) principles with lower dose protocols 2
Alternative Imaging Modalities
Ultrasound as First-Line in Specific Populations
- In infants presenting with stridor, ultrasound can be considered first, particularly for suspected subglottic hemangioma, as it provides bedside assessment of airway narrowing, is non-invasive, and color Doppler establishes vascular nature of lesions 3
- However, ultrasound has limitations including operator dependency and inability to assess thoracic extension or deeply located lesions 3
Common Pitfalls to Avoid
- Do not order non-contrast CT for stridor evaluation, as contrast is essential for distinguishing inflammatory/infectious processes from normal structures and assessing vascularity 2, 1
- Do not delay imaging in stable patients when clinical examination cannot definitively identify the cause, as serious implications for orbits, brain, and spinal cord may be revealed 1
- Remember that CT may fail in certain pediatric cases (such as subglottic hemangioma) where ultrasound or direct tracheobronchoscopy may be more diagnostic 3
Systematic Evaluation Approach
When interpreting neck CT for stridor, systematically evaluate: aerodigestive tract patency and adjacent soft tissues, vascular structures, lymph nodes, thyroid gland, cervical spine, and cutaneous/subcutaneous tissues 1