Radiology of the Antrum

Question 1

What are the four paired air-filled spaces that surround the nasal cavity (paranasal sinuses)?

Answer 1

1. Frontal sinus
   - Above the eyes
2. Ethmoid sinuses (anterior, middle and posterior)
   - Between the eyes
3. Sphenoid sinuses
   - Behind the eyes
4. Maxillary sinuses
   - Under the eyes

Question 2

What are paranasal sinuses lined by

Answer 2

• Respiratory mucosa: pseudo-stratified columnar epithelium with cilia
• Tunica propria has serous and mucous glands
• Underlying this is periosteum

Question 3

Where do all the sinuses drain to?

Answer 3

• Frontal, maxillary antrum, anterior and middle ethmoid air cells all drain to middle meatus of the nose
• Posterior ethmoid air cells and sphenoid sinus both drain to the sphenoethmoidal recess

Question 4

How far does the maxillary antrum extend?

Answer 4

A pyramidal structure

• Base: part of the lateral wall of nose
• Apex: extends into the zygomatic process of maxilla
• Roof: floor of orbit
• Floor: Alveolar process and part of palatine process of maxilla
• Posterior: infratemporal surface of maxilla
• Anterior: facial surface of maxilla

Question 5

Common pathology within the antrum

Answer 5

• Mucus retention cysts
• Polyps
• Rhinosinusitis
• Cysts
• Tumours

Question 6

Common pathology extra-antral

Answer 6

• Dental
• Nose
• Orbit
• Pterygopalatine fossa

Question 7

Imaging of the sinus

Answer 7

• Optimum imagine for sinus disease is multi-slice CT and MRI
• Radiographs you will use can include maxillary antrum
• Dental radiographs may occasionally show disease within the sinus

Question 8

Imaging in acute sinusitis

Answer 8

• Radiographs contraindicated in acute sinusitis cases unless to exclude dental cause of symptoms
• Opacified sinuses or fluid levels may be found with acute sinusitis, which accompanies the common cold in 0.5-5% of cases
• Generally, sinusitis is a clinical diagnosis and management should be by medication
• If the condition does not resolve within 10 days, then imaging may be indicated
• Findings on conventional sinus views can be non-specific and may occur in asymptomatic individuals (e.g. mucosal thickening/mucus retention cysts)
• CT is normally the imagine method of choice