Emergency and Trauma · Neuro and Spine

Acute Neuro and Spine Emergency One-Liners

High-yield one-liners on emergency neuroimaging for stroke, haemorrhage, herniation and acute spinal emergencies including trauma and cord compression.

Rapid-revision one-liners covering emergency neuroimaging for acute ischaemic stroke, intracranial haemorrhage, herniation, and acute spinal emergencies including trauma and cord compression.

Hyperacute stroke CT
Non-contrast CT head is the first investigation in suspected stroke to exclude haemorrhage; early ischaemic signs include dense MCA sign, loss of insular ribbon and sulcal effacement.
ASPECTS scoring
ASPECTS (Alberta Stroke Program Early CT Score) assigns 10 points to MCA territory regions; each region showing ischaemic change subtracts 1 point. Score below 7 indicates large established infarct and poorer thrombectomy outcome.
CT perfusion in stroke
CT perfusion identifies the ischaemic penumbra (Tmax >6 seconds or MTT prolongation) versus the infarct core (CBF <30% or DWI restriction); mismatch ratio guides thrombectomy in extended time windows.
CTA in acute stroke
CT angiography from aortic arch to vertex identifies large-vessel occlusion (LVO) amenable to mechanical thrombectomy; ICA terminus and M1 MCA occlusions are the highest-yield targets.
DWI in hyperacute stroke
DWI with ADC map is the most sensitive MRI sequence for hyperacute ischaemia, showing restricted diffusion within minutes of onset; DWI-negative stroke occurs in approximately 6-8% of cases, particularly in the posterior fossa.
Intracranial haemorrhage density
Acute blood is hyperdense (60-80 HU) on non-contrast CT; active bleeding may show heterogeneous density with swirl sign or spot sign on CTA indicating haematoma expansion.
Epidural versus subdural haematoma
Epidural haematoma is biconvex (lentiform), does not cross sutures but crosses the midline if the sagittal sinus is stripped; subdural haematoma is crescentic, crosses sutures but not the midline.
Subarachnoid haemorrhage CT sensitivity
Non-contrast CT detects SAH with over 95% sensitivity within 6 hours of onset; sensitivity declines thereafter. CT angiography identifies the aneurysm; lumbar puncture is indicated if CT is negative but clinical suspicion remains.
Transtentorial herniation
Uncal herniation shows medial displacement of the uncus compressing the ipsilateral third nerve (pupil dilation) and cerebral peduncle; CT shows effacement of the perimesencephalic cistern and ipsilateral PCA territory infarction.
Tonsillar herniation
Tonsillar herniation is defined by cerebellar tonsil descent below the foramen magnum (>5 mm in adults); causes medullary compression and is rapidly fatal without decompression.
Cervical spine CT clearance
CT is the primary modality for cervical spine clearance in trauma; NEXUS criteria or Canadian C-spine rules guide imaging in alert patients. Obtunded patients with high-energy mechanism warrant CT regardless.
Atlanto-occipital dislocation
AO dislocation is identified by abnormal basion-dental interval (>12 mm) or basion-axial interval (>12 mm) on CT; highly unstable and often fatal.
C2 odontoid fracture classification
Anderson and D'Alonzo classification: Type I (tip avulsion), Type II (base of dens, most common and highest non-union risk), Type III (extends into C2 body).
Hangman fracture
Bilateral pars interarticularis fractures of C2 (traumatic spondylolisthesis) from hyperextension; classified by Levine-Edwards system based on displacement and angulation.
Thoracolumbar burst fracture
Burst fracture involves both anterior and middle columns with retropulsion of bone into the spinal canal; CT with sagittal and coronal reformats is essential for canal compromise assessment.
Spinal cord compression MRI
MRI is the investigation of choice for suspected cord compression (metastatic, epidural abscess or haematoma); T2 signal change within the cord indicates myelopathy and urgency for decompression.
Cauda equina syndrome
Cauda equina syndrome is a surgical emergency; MRI showing large central disc herniation or mass compressing multiple nerve roots with bladder dysfunction warrants emergency decompression within 48 hours.
Spinal epidural haematoma
Spinal epidural haematoma appears as a biconvex extradural collection; hyperacute on T1 iso, hyperacute T2 hyperintense, evolving with blood product age. Anticoagulation is the most common predisposing factor.

Caution

Stroke imaging protocols and thrombectomy time windows are institution-specific and evolving with trial evidence. Always verify current AHA/ASA, ESO or local stroke pathway guidance.

Exam pearl

In viva, always state the time from symptom onset before discussing imaging findings. For spine trauma, name the injured columns and assess stability using the three-column model.

Viva questions

What is the ASPECTS score and what does a score below 7 indicate?
ASPECTS assigns 10 points to MCA territory regions on non-contrast CT or DWI. Each region showing ischaemic change subtracts 1 point. A score below 7 indicates a large established infarct core and is associated with poorer functional outcomes after thrombectomy.
How do you distinguish epidural from subdural haematoma on CT?
Epidural haematoma is biconvex (lentiform), limited by sutures but can cross the midline if the sagittal sinus is stripped. Subdural haematoma is crescentic, crosses sutures freely but is limited by dural reflections such as the falx and tentorium.
What is the imaging investigation of choice for suspected spinal cord compression?
MRI of the entire spine with T1, T2 and STIR sequences is the investigation of choice, as it demonstrates cord signal change, epidural collections, disc herniation and metastatic disease with superior soft-tissue contrast.
What is the significance of the spot sign on CTA in intracerebral haemorrhage?
The spot sign represents active contrast extravasation within an acute intracerebral haematoma on CTA and is a strong independent predictor of haematoma expansion, increased mortality and poor functional outcome.
Describe the three-column model of spinal stability.
Denis three-column model: anterior column (anterior longitudinal ligament and anterior two-thirds of vertebral body/disc), middle column (posterior one-third of body/disc and posterior longitudinal ligament), posterior column (pedicles, facets, laminae and posterior ligamentous complex). Disruption of two or more columns indicates instability.

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