Session 12 Flashcards
Features of radiographs
X ray beam onto plate detector
Quick, cheap, readily available, low ionising radiation dose
Low contrast, 2D
Features of US
Handheld probe using sound waves
Cheap, no ionising radiation
Operator dependent, limited by bone
Useful for thyroid and superficial soft tissue only
Features of CT
X ray beam from passing through a doughnut shaped scanner
Quick, readily available
High radiation dose
Features of MRI
Images acquired from within a magnet- usually shaped like a long tunnel
Best contrast, no ionising radiation
Slow, expensive, limited availability
HNN uses for radiographs
Minor skull trauma (no need for CT)
Cervical spine trauma
Foreign bodies within neck
US HNN uses
Thyroid evaluation
Superficial head and neck masses
Superficial infection
Carotid doppler
CT HNN uses
Trauma- NICE criteria
Acute focal neurological symptoms (evaluate for haemorrhagic strokes)
Malignancy
Infection
Angiographic imaging of arteries and veins
MRI HNN uses
Best imaging of brain - tumour evaluation, epilepsy
Cervical spinal cord traumatic injury
HN tumours
What abnormalities can be seen in a skull radiograph
Skull fracture
Pneumocranium
Fluid level
Lytic soft tissue- Mets/myeloma
Normal lateral skull radiograph
What can be seen on a facial radiograph
Tripod fracture
Black eyebrow
Gas in orbit
TMJ dislocation
Mandibular fracture
cervical spine radiograph can visualise
Fractures/subluxation
Atlanto-axial subluxation
Facet dislocation
Vertebral erosion
Soft tissue widening
Lung lesion/pneumothorax
Jefferson fracture
Caution with radiographs
Cannot see ligamentous injury
Significant injury can be present with normal radiography- consider CT or MRI if spinal crod
Extradural
Features of extradural bleed
Defined traumatic cause
Usually arterial bleed- MMA
Biconvex Oval shape
Associated with fracture 75%
Lucid interval
Neurosurgical emergency
Subdural
Causes of sub dural bleed
Paeds = trauma or NAI
Adult = trauma
Elderly = trauma often mild
Features of sub dural bleed
Usually venous bleed- bridging beins
Crescentic shape
Acute = history of trauma and symptoms
Chronic = confusion
Treatment for sub dural haemorrhage
Correct anticoagulation - warfarin
Small can be managed conservatively - further CT if deteriorate
Large or symptomatic = neurosurgical emergency
Subarachnoid
Caused by trauma or ruptured aneurysm or vessel
Subarachnoid bleed features
Small vessel bleed
Peripheral hyper density following sulci
Can be asymptomatic
Small with normal GCS can be managed conservatively- correct anticoagulation, further CT if deteriorate
Consider neurosurgical option
Features of subarachnoid due to ruptured aneurysm
Arterial bleed due to aneurysm
Central hyper density within subarachnoid space
Thunderclap headache
LP if normal
Neurosurgical emergency- angiographic imaging needed
Subarachnoid specifically ruptured aneurysm
Density of tissues on CT from least to most dense
Air < Fat < Fluid < Soft tissue and blood < bone < metal
Black —> grey —> white
