on call head and neck gladwin hui acknowledgement: special thanks to elissa price
TRANSCRIPT
CT Head and Neck
• Emergency
• Requests from Emerg or ENT
• Talk to referring physician to make sure airway is secured
• IV Contrast
• Neck vs. C-spine
CT Head and Neck
• Difficult studies
• Not very often (maybe once a month)
• Focus on the urgent issues (will take a long time to learn Head and Neck well)
My Approach to CT Neck1) Airway
- Nasopharynx, oropharynx and hypopharynx (whole airway)- Trachea and esophagus
2) Deep neck spaces- Parapharyngeal space- Retropharyngeal space- Masticator space- Carotid space- Perivertebral space- Anterior visceral space- Submandibular/sublingual space
Approach to CT Neck
3) Glands- Parotid- Submandibular- Thyroid
4) Vessels and lymph nodes5) Bones and Soft tissues6) Neuro
- Brain, orbits, paranasal sinuses, mastoid air cells7) Cord8) Chest
- Lung apices - Mediastinum, Pericardial region
Approach to CT Neck
• Bottom Line
– Check your ABC’S– A = AIRWAY– B = BONES– C = CAROTID SHEATH/VESSELS– S = SPINAL CORD/CANAL
Anatomy: Fat Planes & Spaces
• Deep neck spaces
• - Parapharyngeal space
• - Retropharyngeal space
• - Masticator space
• - Carotid space
• - Perivertebral space
• - Anterior visceral space
• - Submandibular/sublingual space
Anterior Visceral Space
• Extends from hyoid bone to anterior mediastinum
• Sling around the trachea, esophagus
• Contiguous with the retropharyngeal space
Retropharyngeal Space
• Extends from skull base to superior mediastinum
• Limited anteriorly by middle layer of deep cervical fascia, and posteriorly by deep layer of deep cervical fascia
• Extends to mid T-spine, then connects to Danger space and closed off by connective tissue at carina
• Content: Fat, LN
Danger Space
• Extends from skull base to diaphragm in the posterior mediastinum
• Posterior to retropharyngeal space
• Lies between the alar and prevertebral layers of the deep cervical fascia
• Spread of infection from neck to mediastinum
Carotid space – Neurovascular Bundle
• Extends from skull base to mediastinum
• CCA, IJV, Vagus– Dissection, narrowing, aneurysm, rupture– Thrombus– Mass
Parapharyngeal Space
• Key landmark – primarily fat-containing– How is it being effected by a process going on
in the region?
Tonsil
Submedial pterygoid space
Parapharyngeal space
Parotid gland
Neurovascular bundle
Retropharyngeal space
Cellulitis
• Focal or diffuse
• Streaky infiltration of fat planes
• Diffuse enlargement of adjacent muscles
• No focal loculation of fluid
Phlegmon
• Slightly heterogeneous solid swelling
• May be minimal low density suggestive of fluid loculation developing
• Usually seen in tonsillar/peritonsillar or retropharyngeal locations
Fluid Collections
• homogeneous or minimally heterogeneous
• no good peripheral margin, no enhancement
• turns the fat planes grey
Abscess
• Well-defined capsule
• Little or no cellulitic change in adjacent tissues
• Often adjacent to bone (secondary to osteomyelitis)
Complications
ALWAYS CHECK FOR:• Airway obstruction
• Carotid pseudoaneurysm or rupture
• Internal jugular vein thrombosis
• Mediastinitis/fluid collection/abscess
• Pericarditis
Dental Infections
• Usually mandibular, usually molar
• Submedial pterygoid space
• Floor of mouth
• Anterior visceral space
• Parapharyngeal space
• Neurovascular bundle
• Retropharyngeal space
Ludwig’s Angina
• Cellulitis that involves inflammation of the tissues of the floor of the mouth, under the tongue
• Extremely dangerous• Early airway compromise• Extensive edema of tongue and floor of mouth• +/- Floor of mouth fluid/air• No abscess• Dental origin
Tonsil
• Unilateral swollen tonsil
• Parapharyngeal space
• Floor of mouth
• Neurovascular bundle
• Retropharyngeal space
Pharyngeal/Esophageal Perforations
• Air in the fat planes
• Retropharyngeal space
• Neurovascular bundle
• Mediastinum
My Approach to CT Neck1) Airway
- Nasopharynx, oropharynx and hypopharynx (whole airway)- Trachea and esophagus
2) Deep neck spaces- Parapharyngeal space- Retropharyngeal space- Masticator space- Carotid space- Perivertebral space- Anterior visceral space- Submandibular/sublingual space
Approach to CT Neck
3) Glands- Parotid- Submandibular- Thyroid
4) Vessels and lymph nodes5) Bones and Soft tissues6) Neuro
- Brain, orbits, paranasal sinuses, mastoid air cells7) Cord8) Chest
- Lung apices - Mediastinum
Approach to CT Neck
• Bottom Line
– Check your ABC’S– A = AIRWAY– B = BONES– C = CAROTID SHEATH/VESSELS– S = SPINAL CORD/CANAL
Good resources
• Statdx• http://www.med.wayne.edu/diagRadiology/
Anatomy_Modules/axialpages/Overview.html