What is 1st line when looking at the brain?
CT; fast, well tolerated, with or without IV contrast
What is MRI better for in terms of brain imaging?
Better soft tissue resolution
Longer duration
Contra-indicated for some
With or without TV contrast
What is an ischaemic stroke?
Suddent cessation of adequate amounts of blood to the brain
Can be divided according to the territory affected or mechanism
How do ischaemic strokes tend to present?
Rapid onset neurological deficit, which is determined by the area of brain involved
Deprivation of oxygen and glucose
Initiates a cascade of events at a cellular level which can lead to gliosis and liquefactive necrosis
What is the end point of a stroke?
Gliosis
Liquefactive necrosis
What conditions can lead to cardiac embolism?
Atrial fibrillation
Ventricular aneurysm
Endocarditis
What can lead to embolisms?
Cardiac emoblism Paradoxial Atheroscelrotic Fat Air
What area of the brain is most affected by hypertensive haemorrhagic strokes?
Basal ganglia
Imaging of choice in acute stroke?
Non contrast CT
Why is a non contrast CT performed in acute stroke?
Exclude haemorrhage and confirm ischaemia
Permits RAPID treatment e.g. thrombolysis or thrombectomy
Early findings on CT of an ischaemic stroke?
Hyperdense segment of a vessel, direct visualisation of the intravascular thrombus/ embolus and as such is visible immediately
What findings are seen within a few hours of an ischaemic stroke?
Loss of grey white matter differentiation and hypoattenuation of deep nuclei
Cortical hypodensity with assoc parenchymal swelling with resultant gyral effacement
What will happen with the hypodensity seen in ischaemic stroke as time progresses?
More marked resulting in a mass effect
What are the end stages appearances of an ischaemic stroke on CT?
Gliosis as a region of low density with volume loss
What are the different types of extra-axial intracranial haemorrhages?
Extradural
Subdural
Subarachnoid
What colour will blood appear on a CT scan?
White
What will an intra-axial hemorrhage appear like on a CT?
LOBAR haematoma
Midline shift may be present
Where is the blood in an extradural haemorrhage?
Between inner layer of skull and outer layer of dura
What are extradural haemorrhages commonly assoc with?
Trauma
Skull #
What is the source of bleeding in an extradural haemorrhage?
Arterial
Torn middle meningeal artery
What shape is the haemorrhage seen in an extradural haemorrhage?
BICONVEX
Can cause mass effect with herniation
Limited by cranial sutures
Where is the blood collection in a subdural haemorrhage?
Subdural space, the potential space between the dura and the arachnoid mater
What is the mainstay of investigation in subdural haemorrhages?
CT
What causes subdural haemorrhages?
Infants; NAI (shaken baby syndrome)
Young Adults; RTA
Elderly; falls (tearing of bridging veins)
What shape is the subdural haemorrhage?
Semilunar
Crosses sutures
Mass effect
Where is the blood in a SAH?
Subarachnoid space;
Between arachnoid and pia
What are 85% of SAH due to?
Ruptured berry aneurysm
Where will blood be seen in a SAH?
Suprasellar cistern
Sylvian fissure
Sulci
What is the gold standard for SAH?
CT cerebral angiogram
What are common complications of SAH?
Hydrocephalus
Vasospasm
Infarction
What make up the majority of brain tumours in adults?
Metastatic disease
What makes up the majority of brain tumours in children?
Primary tumours
What areas of the body will metastasise to the brain?
Lung Breast Melanoma Renal cell Colorectal
What is the first test when suspected intracranial mass?
CT
Hypo or hyperdense
Determines oedema/ mass effect
What are the features of mets in the brain?
Supra or infra tentorial Usually multiple Lots of oedema Lots of mass effect Avidly enhance
What type of herniation results in “coning”?
Tentorial herniation; descent of cerebellar tonsils below the foramen magnum compressing the brain stem against the clivus
What is the spinal cord contained within?
Thecal sac
Where does the spinal cord extend to - from?
Corticomedullary junction at the foramen magnum of the skull down to the tip of the conus medullaris (L1)
What can cause spinal cord compression?
IV disc; protrusion, extrusion, discitis, osteomyelitis Vertebral; trauma, tumour Epidural space; abscess, haematoma Dura; spinal meningioma Intradural space; nerve sheath tumour
What is the investigation of choice in spinal cord compression?
MRI spine
What are red flags in terms of back pain?
History of malignancy Major trauma Thoracic/ radicular pain Constant, progressive, non-mechanical pain Widespread neurological signs Loss of power in lower limbs Loss of sensation; saddle anaesthesia Urinary retention