CT neck protocols Flashcards
CT post contrast neck indications
Cysts Abscesses Masses Lymph Nodes Salivary assessment Laryngeal tumour
CT post contrast protocol
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)
CT post contrast, contrast requirements
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
CT post contrast possible pathologies
Cyst Thyroid nodules Submandibular lipoma Retropharyngeal mass Aspergillosis Thyroid carcinoma
CTA neck carotid indication
Aneurysm
Occlusion
Stenosis
Dissection
CTA neck carotid protocol
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
CTA neck carotid contrast requirements
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
CTA neck carotid possible pathologies
stenosis
occlusion
aneurysm
dissection
CT neck protocol alterations for trauma patient
-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
CT neck protocol alterations for paediatric patient
-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
CT neck protocol for geriatric patient
-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
CT neck protocol alterations for uncooperative patients
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
