CT Pns

A CT PNS (Computed Tomography of the Paranasal Sinuses) captures cross-sectional pictures of the air-filled spaces around your nose and eyes. The scan:

• Takes less than 10 minutes
• Requires no injections in most cases
• Delivers high-resolution 3D images
• Guides ENT specialists in planning surgery or medical treatment

CT PNS is a specialized X-ray technique that rotates around your head, creating thin “slices” of your sinus cavities. The computer stitches these slices into a 3D map, revealing:

• Mucosal thickening
• Fluid levels
• Bony abnormalities
• Septal deviation

How it differs from regular CT

Unlike a full-head scan, CT PNS focuses only on sinus regions, reducing both scan time and radiation dose.

Radiologists review:

• Lund-Mackay score for mucosal disease extent
• Ostiomeatal complex patency
• Septal deviation angle
• Haller cell presence
• Concha bullosa size

• Confirm chronic rhinosinusitis
• Detect complications like orbital abscess
• Evaluate trauma-related fractures
• Map anatomy before sinus surgery

Common triggers

• Recurrent sinus headaches
• Nasal obstruction lasting >4 weeks
• Suspected sinusitis unresponsive to antibiotics
• Pre-surgical evaluation for FESS (Functional Endoscopic Sinus Surgery)

Age groups

• Adults: most common
• Children: when chronic symptoms persist and simpler imaging has failed

• Quick: 5–10 minutes scan time
• Accurate: detects 1 mm lesions
• Non-invasive: no scopes inside the nose
• Guides therapy: reduces unnecessary antibiotics

• Acute and chronic sinusitis
• Nasal polyposis
• Mucocele or pyocele
• Sinonasal tumors
• Deviated nasal septum
• Fungal balls or allergic fungal sinusitis

• Remove earrings, glasses, and metal hairpins
• Wear a hospital gown if clothing has metal zippers
• No fasting required for non-contrast scans
• For contrast studies: 4-hour fasting and kidney function test (if diabetic or >60 yrs)

• Doctor’s prescription
• Previous scan films (if any) for comparison
• Pregnancy test for women of child-bearing age opting for contrast
• KFT report if contrast is planned

• Morning slots reduce wait times and provide same-day reports
• Avoid during active nosebleeds—wait until bleeding stops

Suitable

• Adults and children >5 yrs with persistent symptoms
• Patients scheduled for sinus surgery

Unsuitable

• Pregnant patients (unless urgent)
• Individuals with severe contrast allergy

1. Check-in: arrive 15 min early
2. Metal removal: store valuables in locker
3. Positioning: lie on the CT table, head in a soft holder
4. Scan: stay still for 5–10 seconds while the machine rotates
5. Contrast (if needed): IV line inserted; warm sensation felt for 30 sec
6. Completion: table slides out; immediate return to normal activities

• Notify staff of kidney disease or diabetes if contrast is used
• Carry list of current medications—some may interact with contrast dye
• Remove eye makeup; metallic particles can distort images

Risks

• Radiation exposure: comparable to 6 months of natural background; still kept ALARA (As Low As Reasonably Achievable)
• Pregnancy: inform staff if you are or might be pregnant

Limitations

• Cannot always separate active infection from post-infection scarring
• Metallic dental fillings may create streak artifacts