Radiology of Trauma Flashcards
What does imaging constitute in terms of head trauma?
Important part in modern day practice
What has a lot of guidelines been looking at?
Indication for imaging
When is there enhanced role for CT?
After head injury
What is enhanced role for CT after head injury advocated by?
- Neurosurgeons in 1990 and 1998, 1999 guidelines from RCSEng
Historically, what is the only imaging that are performed in form of head trauma?
Skull radiographs
Extremely unreliable
Variable reliability
What is the reliability of head trauma?
ER clinicians miss 13-23%
What does skull radiographs have?
Low sensitivity
What is CT sensitivities and specifities 100% for?
Detecting and locating a surgically significant focal intracranial lesion
What is the effect of Admissions?
- Most patients would be admitted for observations
- Specialists observations are required
- Only 1-3% develop life-threatening intracranial pathology
- Remainder home after 48 hours observation
- Significant resource burden on the NHS
- Quality of observations
- Limited emergency neurosurgical beds in the UK
- Secondary deterioration delayed with routine neurological observations
What is the morbidity of Head trauma?
- Mismanage head injury
- High level of disability following minor/mild head injury
- Far exceeds capacity of UK neuro-rehabilitation services
What are the imaging modalities for head trauma?
SXR limited usefulness:
- Calvarial fractures
- Penetrating injuries
- Radiopaque foreign bodies
What is the Computed Tomography (CT)?
- Main: imaging head trauma in acute setting
What is CT sensitive for?
Mass effect (brain shift)
Ventricular size
Bone Injuries
Acute haemmorhage
What is the limitations for CT including insensitivity in detecting?
- Small and non-haemorrhagic lesions (e.g. contusion)
- DAI
- Detecting increased ICP or cerebral oedema
- Early demonstration of HIE
What is MRI good for?
Looking at tissue discrimination therefore finer points of tissue injury
What does MRI look at?
Specific sequences to look at by-product of haemorrhage [determining the extent of damage]
What is DWI used for?
Impeding infarction or established infarction
What is MRI sensitive for?
Subacute and chronic brain injuries
-Hemosiderin-sensitive T2W GRE + SWI sequences
What does DWI improve?
Detection of acute infarction
What is FLAIR imaging sensitive for?
Subarachnoid haemorrhage and lesions bordered by CSF
What is required for non-haemorrhagic primary lesions (contusions) or secondary effects (oedema, HIE, DAI)?
Superior contrast resolution
What is MRI hindered by?
- Limited availability in acute trauma setting
- Long Imaging times - sensitivity to patient motion
- Relative insensitivity to subarachnoid haemorrhage
- Medical devices incompatability unless MRI-specific
- Risk of in-dwelling devices or forgein bodies
What are examples of foreign bodies?
- Cardiac pacemaker
2. Cerebral aneurysm clip