Brain Imaging Flashcards
What is first line investigation for brain?
CT with or without IV contrast
Which type of imaging is best for soft tissue resolution and shows grey white matter definition?
MRI
What are downsides of MRI? (3)
Long scan
Contra-indicated for some e.g. pacemakers
not suitable for acutely unwell patients
What cistern is the circle of Willis in?
Supracellar cistern
What colour is fluid in T1 and T2 weighted MRIs?
T1- black fluid
T2 - white fluid
What are 2 types of intracranial haemorrhage & 3 types of second one?
Intra-axial - within brain substance
Extra-axial - out with brain parenchyma but inside the skull
- extra dural, SU dural, subarachnoid
What is typical appearance of hypertensive bleed?
Acute haematoma in the right basal ganglia (thalamus)
What is most common cause of extradural haemorrhage?
Trauma, especially skull fracture
What haematoma is lentiform (biconvex) shaped?
Extramural haematoma
In terms of age groups (Elderly, young and infants) what are the most common causes of subdural haemorrhages in each group?
Elderly - falls
Young - RTA
Infants - NAI e.g. shaken baby syndrome
What is classic shape of subdural haematoma?
Semilunar shape
Subdural haematomas do not cross the sutures. True/false?
False - they do cross sutures
How do subacute haemorrhages present on imaging?
And how do chronic haemorrhages present on imaging?
Subacute - isodense - mixed attenuation (blood is mixed)
Chronic - hypodense - low attenuation
WHere is subarachnoid most commonly
85% berry aneurysm
Arising in circle of Willis
Can be traumatic/vascular malformations
How do subarachnoid haemorrhages present on brain imaging?
Hyper dense material seen in subarachnoid space
What is the next step after CT when subarachnoid blood is found in the absence of appropriate history of trauma?
CT cerebral angiogram for berry aneurysm
What are 3 complications of subarachnoid blood being in brain?
hydrocephalus, vasospasm and infarction
What is the most common type of brain tumour in adults and kids?
Adults - metastasis
Kids - primary brain tumours
Metastasis tend to be very irritant and cause a lot of oedema and mass effect & tend to be rounded lesion with hyper dense outer and hypodense . True/false?
True
Metastasis tend to pick up IV contrast well. True/false?
True
What 3 imaging factors change depend on grade of tumour?
Degree of oedema
Mass effect
Enhancement
What is coning and why is it fatal if not corrected?
Cerebellar tonsillar herniation below the foramen magnum
Fatal because brainstem compressed against Clivus which affects cardiac and respiratory centres of pons and medulla
What is name of bag of spinal cord
Thecal sac
From where in brain does spinal cord extend from
Corticomedullary junction
