ct mastoid

 

 CT mastoid indication,Technique and Procedure

• Headache
• Hearing loss in the affected ear. 
• Swelling behind the ear.
• Labyrinthitis
• Facial nerve dysfunction
• Epidural abscess
• Petrous apicitis
• Earache

Technique 

• Patient preparation : Remove metallic objects including earrings, necklaces. 
• Patient position : head first and supine with their arms by their body.
• Tube voltage : 120 to 130 kVp.
• Scout : Frontal sinus to vertex.
• Scan direction : Caudocranial.
• Scan geometry Slice thickness 0.6 mm.
• Respiration phase :  Suspended.

• InnerEarSeq kV 120 
• Effective mAs 90 
• width 0.6 mm 
• Feed/Scan 1.0 mm 
• Rotation time 1.0 sec. 
• Kernel U90s 
• Image order ca-cr
• CTDIw 39.6 mGy 
• Effective dose:  Male: 0.6 mSv Female: 0.6 mSv 
• For image reconstruction of soft tissue, use kernel U30. 

Contrast protocol : 

• Non-contrast performed first.
• Start delay 60 sec -Flow rate 2 ml/sec
• Post-contrast 50 cc hand injection.