CT neck protocols Flashcards Preview

MRS432- CT > CT neck protocols > Flashcards

Flashcards in CT neck protocols Deck (12)
Loading flashcards...
1
Q

CT post contrast neck indications

A
Cysts 
Abscesses 
Masses 
Lymph Nodes 
Salivary assessment 
Laryngeal tumour
2
Q

CT post contrast protocol

A

Commonly scanned with the patient lying supine, head first in the scanner with arms by their side. Chin slightly raised (to have head/neck in a straight line)

Dual Scouts usually performed; allow for a tighter field of view to maximise resolution when the scanner reconstructs the images

Scan direction covers from arch of aorta (T4) to pit fossa (COW). ? Reduce scan range

Fine slice thickness with overlapping slices (Pitch <1)

Soft algorithm with w/w 350, w/l 40 (approx..)

Scan performed on suspended respiration and asked not to swallow

If immovable metal objects such fillings use metal artefact reduction if available

Axial, Coronal and Sagittal MPR’s (2-5mm)

3
Q

CT post contrast, contrast requirements

A

IV contrast (50-75ml), unless contra-indicated

Injection rate 2.0-3.5 ml/sec depending on vein and patient size

20 gage cannula is acceptable, in L or R cubital fossa

Can be timed scan at 40-50 sec or bolus tracked at aorta arch 20-30 sec delay

Dual phase venous and arterial

4
Q

CT post contrast possible pathologies

A
Cyst
Thyroid nodules
Submandibular lipoma
Retropharyngeal mass
Aspergillosis
Thyroid carcinoma
5
Q

CTA neck carotid indication

A

Aneurysm
Occlusion
Stenosis
Dissection

6
Q

CTA neck carotid protocol

A

CTA of neck vessels to highlight arteries of neck

Patient positioned supine head first with arms by their side. Chin slightly raised (to have head/neck in a straight line)

Scan from aortic arch to Circle of Willis

Dual Scouts usually performed; allow for a tighter field of view to maximise resolution when the scanner reconstructs the images

Scan with thinnest slice thickness overlapping for reformats/3D (pitch <1)

Fast tube rotation time to reduce time of scan

Reformats will be Ax, Cor, Sag average and slab MIPS. 3D recons and curved vessel extractions. Anything else radiologist or referrer requires

Window on individual basis to distinguish between contrast and calcium. Start @ WW 1000 and WL 400

7
Q

CTA neck carotid contrast requirements

A

Large cannula (18g) in right arm to reduce artefact at vessel origins

Scan from aortic arch to Circle of Willis

Pressure inject 75-100 ml contrast @ 4-5 ml/sec. Many sites will use duel injection syringes with saline push @ same rate

Bolus track off aortic arch with minimum trigger delay

8
Q

CTA neck carotid possible pathologies

A

stenosis
occlusion
aneurysm
dissection

9
Q

CT neck protocol alterations for trauma patient

A

-Trauma patient: lots of staff, quick scan, organised room ready to scan

Contrast volume dependent on patient size

Fast non-con scan to prevent patient movement and risk of repeating

Metallic artefact from fillings etc. Use metal artefact reduction

Pronounced kyphotic curve. Common in the elderly, may need to prop head up higher

Poor venous access. Small cannula ok for ST neck not for CTA. May need ultrasound guidance for cannulation

Trauma or unconscious patient place equipment away from area to be scanned as much as possible and turn off auto instructions

10
Q

CT neck protocol alterations for paediatric patient

A

-Paediatric patient: parent in the room, sedations/ GA, secure head, organised and quick scan, simple explanation

Contrast volume dependent on patient size

Fast non-con scan to prevent patient movement and risk of repeating

Poor venous access. Small cannula ok for ST neck not for CTA. May need ultrasound guidance for cannulation

Trauma or unconscious patient place equipment away from area to be scanned as much as possible and turn off auto instructions

11
Q

CT neck protocol for geriatric patient

A

-Geriatrics: secure head, explain simply, organised and quick scan

Contrast volume dependent on patient size

Fast non-con scan to prevent patient movement and risk of repeating

Metallic artefact from fillings etc. Use metal artefact reduction

Pronounced kyphotic curve. Common in the elderly, may need to prop head up higher

Poor venous access. Small cannula ok for ST neck not for CTA. May need ultrasound guidance for cannulation

If patient hard on hearing turn auto instructions up as you need to remove hearing aids

Trauma or unconscious patient place equipment away from area to be scanned as much as possible and turn off auto instructions

12
Q

CT neck protocol alterations for uncooperative patients

A

immobilisation devices, alter parameters for a fast scan, staff to help

Contrast volume dependent on patient size

Fast non-con scan to prevent patient movement and risk of repeating

Metallic artefact from fillings etc. Use metal artefact reduction

Pronounced kyphotic curve. Common in the elderly, may need to prop head up higher

Poor venous access. Small cannula ok for ST neck not for CTA. May need ultrasound guidance for cannulation

Trauma or unconscious patient place equipment away from area to be scanned as much as possible and turn off auto instructions