week 4, lec 2- head CT protocols

Question 1

what is the patient preparation for CT head scan?

Answer 1

Informed consent 
Check for contraindications
Procedure explanation
Contrast questionnaire
Remove metal from head
Consider MAR for permanent metal
Look at potential previous scans of head

Question 2

what are different scout images called

Answer 2

• Surview
• Pilot
• Scanogram
• Topogram
• Scout

Question 3

what are 5 indications for a CT non con brain

Answer 3

Trauma 
CVA/TIA 
SDH/SAH 
Unexplained severe headaches 
Dementia/Memory Loss 
Psychiatric  
Speech difficulty 
Difficulty swallowing 
Ventricular size 
Bone / Skull abnormalities

Question 4

what are 5 NM variations of CT non con brain

Answer 4

Most commonly associated with PET 
Often combined with CAP 
Full body cancer work up 
Performed as post contrast scan 
Secure and comfortable 
PET Long scan time 
SPECT / CT used to look at brain function but has limited clinical use

Question 5

what are 5 RT variations of CT non con brain

Answer 5

Head secured in treatment position using thermoplastic mask

Mask is secured to flat table top

Identical reproduction for treatment

Usually performed Non Contrast and fused with MRI

Scanned on larger field of view to include table

Pitch often larger than diagnostic as lower resolution is required

Question 6

what is the slice thickness and type of MPR for non con CT brain

Answer 6

Common 2-3 planes at 2.5mm

Brain and bone window

Question 7

what are 5 indications for CT contrast brain

Answer 7

Further characterisation of SOL 
Metastases 
Characterisation of ICH seen on unenhanced scan 
AVM 
Epilepsy
Infections 
Seizures (especially recent onset)

Question 8

what is the patient prep for CT contrast brain

Answer 8

2 hour fast
Patent cannula
Contrast: 40mLs of Ultravist 370 contrast

Question 9

list 5 indications for CT sinuses and facial bones

Answer 9

Sinusitis 
Polyps 
Trauma 
Surgical planning 
Neoplastic disease of nose, nasopharynx or sinuses (+C)

Question 10

what are 4 indications for non con IAMs/PTBs

Answer 10

Vertigo
Hearing loss
Cholesteatoma
Mastoiditis

Question 11

what are 2 indications for contrast IAMs/PTBs

Answer 11

• Acoustic neuroma

- Tinnitus

Question 12

what is 1 indication for orbits +/- brain (non con)

Answer 12

Trauma/ foreign body

Question 13

what is 5 indications for orbits +/- brain (contrast)

Answer 13

Infection/Abscess 
Optic nerve mass
Proptosis/Diplopia 
Vision loss 
Melanoma

Question 14

what is a CTA COW protocol

Answer 14

Performed as stand-alone study or as part of head and neck CTA
Coverage will vary with indication from COW only to whole brain
Position chin down as per Brain
Soft algorithm and individual window to differentiate between contrast and calcification
Small SFOV
Thin slice
Pitch <1 / overlap
Common indications: aneurysm, stroke, AVM
Contrast scan in arterial phase
50-100ml @ 4-5ml/sec
Contrast timing can be aided by bolus tracking
MPR ave. MIP, various 3D rendering methods

Question 15

what needs to be taken into account when imaging trauma patients?

Answer 15

? Unconscious / Unstable patient
Lots of staff
Leads, wires & monitors
Hard collar? 
Other injuries? 
Contrast? 
Organised room
Ready to scan
Quick
Send images for reporting / viewing
Clean up
Ready room again

Question 16

what needs to be taken into account when imaging paediatric patients?

Answer 16

Methods can vary with age
Sedation / GA required? 
Parent / other in room? 
Minimise dose
Secure head
Explain simply
Reassure them
Organised / quick

Question 17

what needs to be taken into account when imaging geriatric patients

Answer 17

Physical limitations
Comorbidities
Medication
Secure head
Explain simply
Reassure them
Organised / quick

Question 18

what needs to be taken into account when imaging uncooperative patients

Answer 18

Altered mental state
Alcohol and drug affected
Aggressive
Confused
Safety is priority
Use straps and immobilisation devices
May need to alter parameters for faster scan to reduce chance of movement
Have back-up