Trauma

Question 1

37. Which of the following features favours extradural rather than subdural haematoma?

A. Extra-axial collection

B. Mixed hyper and hypodense areas

C. Crossing of sutures

D. Crossing of dural attachment

E. Skull fractures

Answer 1

D. Crossing of dural attachment

Both are extra-axial and can be of mixed attenuation. Although skull fractures are more common in EDH, this cannot be the single best answer as EDH cross dural attachments are limited by cranial sutures.

Question 2

@# 40) A 35-year-old man is involved in a low-velocity road traffic accident. Within minutes, he experiences an occipital headache and neck pain. On arrival in hospital, he complains of nausea, vertigo and diplopia. An unenhanced CT scan of the brain is performed. Which of the following abnormal findings is most likely?

a. high density seen in CSF of the sylvian fissure

b. low density and loss of grey–white matter differentiation in the insular region

c. expansion of a vertebral artery with a peripheral, high-density crescent

d. lenticular high attenuation between the temporal lobe and temporal bone

e. crescent-shaped high attenuation between the temporal lobe and temporal bone

Answer 2

c. expansion of a vertebral artery with a peripheral, high-density crescent

Minor trauma stretching the vertebral artery over the lateral mass of C2 can cause vertebral artery dissection.

Symptoms include headache and neck pain, and as many as 95% of patients develop a stroke after hours to weeks. Imaging will show an axially enlarged vessel with a narrow lumen and a periarterial rim sign.

Angiography may demonstrate tapering or occlusion of the artery or the dissection flap.

Predisposing factors to spontaneous arterial dissection include fibromuscular dysplasia, Marfan’s syndrome, collagen vascular disease and homocysteinuria.

Question 3

53) A 50-year-old female presents with a ‘thunder-clap’ headache and fluctuating level of consciousness. Unenhanced CT of the brain shows high-density material layered in the occipital horns of the lateral ventricles. Which of the following is the most appropriate next imaging investigation?

a. CT angiography

b. CT venography

c. MR angiography

d. catheter angiography

e. radionuclide regional cerebral blood flow imaging

Answer 3

a. CT angiography

Some 80–90% of subarachnoid haemorrhage is due to aneurysmal rupture.

Therefore, when the diagnosis is proven or strongly suspected, the cerebral arterial circulation requires assessment.

Sixteen-slice CT angiography (CTA) is as accurate for aneurysm detection as 2D catheter digital subtraction angiography (DSA).

CTA can be used as primary imaging and DSA reserved for difficult cases.

It has the advantages of being safe, immediate, swift and less likely to need sedation or general anaesthetic.

CTA also offers anatomical information beyond just the cerebral vasculature, in contrast to DSA.

With 16-slice CTA, the spatial resolution is similar to DSA: 0.40 mm for CTA and 0.32 mm in DSA (2D DSA 33 cm FOV, 1024_1024 matrix, resolution 0.32_0.32 mm). When DSA is performed with AP and lateral projections, aneurysms may be masked, but 3D rotational DSA avoids this problem. The CTA parameters are as follows: 0.5 rotation/s with a 10 mm table advance per rotation and a 5-s scan, 16 rows of 0.75 mm reconstructed to 0.4 mm, kVp 120, mA 130.

Question 4

55) One week following a subarachnoid haemorrhage, a 50-year-old female, who had thus far been making a good recovery, develops intractable vomiting, vertigo and ataxia. An unenhanced CT of the brain demonstrates unchanged ventricular size but a new hypodense region in a cerebellar hemisphere. Which of the following complications of subarachnoid haemorrhage is most likely to have occurred?

a. acute obstructive hydrocephalus

b. delayed communicating hydrocephalus

c. vasospasm and infarction

d. transtentorial herniation

e. rebleed from a berry aneurysm

Answer 4

c. vasospasm and infarction

Infarction in this case is cerebellar.

Vasospasm is the leading cause of death and morbidity following subarachnoid haemorrhage.

It occurs after 72 hours with a peak at 5–17 days.

Acute obstructive hydrocephalus results from intraventricular blood or the resultant ependymitis obstructing the aqueduct of Sylvius or the outlet of the fourth ventricle.

Communicating hydrocephalus usually occurs after 1 week when the haemorrhage causes impaired CSF absorption.

Question 5

@# 69) In the presence of raised intracranial pressure, the anterior cerebral artery is at risk of compression during which of the following types of brain herniation?

a. transforaminal herniation

b. sphenoid herniation

c. ascending transtentorial herniation

d. descending transtentorial herniation

e. subfalcine herniation

Answer 5

e. subfalcine herniation

Transtentorial herniation may be descending (towards the posterior fossa) or ascending (upward displacement of the cerebellum through the tentorial incisura).

Descending transtentorial herniation causes shift of the temporal lobe over the tentorium, which may compress the third cranial nerve, the posterior cerebral and anterior choroidal arteries, and the midbrain.

Contralateral hemiparesis may occur due to compression of the ipsilateral cerebral peduncle.

Ipsilateral hemiparesis may also occur due to compression of the contralateral cerebral peduncle against the tentorial edge (Kernohan’s notch phenomenon, a false localizing sign).

Subfalcine herniation occurs when the cingulate gyrus shifts beneath the falx, due to medially directed supratentorial mass effect. This may cause compression of the anterior cerebral artery (resulting in ipsilateral distal anterior cerebral infarction) and internal cerebral veins.

Sphenoid herniation involves herniation of the frontal lobe posteriorly across the edge of the sphenoid ridge, and rarely produces significant clinical symptoms.

Transforaminal herniation results in herniation of the inferior cerebellum downward through the foramen magnum, which can result in obtundation and death.

Question 6

80) A 24-year-old man is an unrestrained passenger in a car involved in a high-speed collision. He is found unconscious at the scene. CT of the brain is normal. MR scan of the brain demonstrates multiple small foci of high signal on T2W images in the white matter of the parasagittal regions of the frontal lobes and the periventricular regions of the temporal lobes. What is the most likely diagnosis?

a. acute subdural haematoma

b. diffuse axonal injury

c. cortical contusions

d. intracerebral haematoma

e. subcortical grey matter injury

Answer 6

b. diffuse axonal injury

Diffuse axonal injury is characterized by widespread axonal disruption occurring in response to acceleration or deceleration forces – direct impact is not necessary.

Typically, patients are immediately unconscious after the injury.

CT is commonly negative, though 20% of lesions contain sufficient haemorrhage to be visible.

On MR scan, typical findings are of multiple small foci of decreased signal intensity on T1W images and increased signal intensity on T2W images.

Characteristic locations are the frontal and temporal white matter near the grey–white matter junction.

More severe injuries may involve the lobar white matter and corpus callosum, with the brain stem involved in the most severe cases.

Cortical contusions usually involve the superficial grey matter, and patients are less likely to present with immediate loss of consciousness. They characteristically occur near bony protuberances and are more commonly haemorrhagic.

Subcortical grey matter injury is an uncommon type of injury seen after severe head trauma, with petechial haemorrhages in the basal ganglia and thalamus.

Question 7

93) A 14-year-old boy is hit by a vehicle while riding his bike and sustains a left-sided head injury. Paramedics report a transient loss of consciousness at the scene. On examination, he is confused with a GCS of 13/15. Unenhanced CT of the brain is performed, which shows a biconvex extra-axial collection in the left temporoparietal region with attenuation value of 65 HU. On bone windows, there is an undisplaced, linear, left temporoparietal skull fracture. What is the most likely diagnosis?

a. acute subdural haematoma

b. acute extradural haematoma

c. acute subarachnoid haemorrhage

d. acute intracerebral haematoma

e. cerebral cortical contusion

Answer 7

b. acute extradural haematoma

Acute extradural haematomas are traumatic in origin and tend to be commoner in younger patients.

Two-thirds of cases involve the temporoparietal region, and 75–95% of patients have an associated skull fracture.

Bleeding is usually from the underlying middle meningeal artery, though it may also be due to disruption of the middle meningeal vein, dural venous sinuses or diploic veins.

Typical appearances are of a high-density lentiform or biconvex collection, which forms between the inner table of the skull and the dura mater.

The dura is firmly bound to the skull at sutural margins, so extradural haematomas tend not to cross suture lines.

Acute subdural haematomas usually follow severe trauma, and have a poorer prognosis than acute extradural haematomas due to a high incidence of associated contusions and other brain injuries.

They tend to be crescentic in shape and may freely extend across suture lines, being limited only by the interhemispheric fissure and tentorium.

They are commonly bilateral, particularly in infants, and have no particular association with skull fractures.

Question 8

20 A 23 year old man is involved in an RTA as a passenger and arrived in A&E with a GCS of 3/15. The initial CT head is reported as normal. Diffuse axonal injury is suspected and an MRI is arranged. Which of the following structures are most likely to be affected?

(a) The splenium of the corpus callosum

(b) The inferior cerebellar peduncle

(c) The tegmentum

(d) The basal ganglia

(e) The hypothalamus

Answer 8

(a) The splenium of the corpus callosum

Diffuse axonal injury is most likely to affect the lobar grey/ white matter junction, the corpus callosum, the dorso-lateral brainstem and the internal capsule. There is relative sparing of the cortex.

Question 9

21 Which is the commonest type of cerebral herniation?

(a) Subfalcine

(b) Transtentorial

(c) Transalar

(d) Tonsilar

(e) Transcranial

Answer 9

(a) Subfalcine

Subfalcine is the commonest type of herniation.

Question 10

30 A patient presents with thunderclap headache, vomiting and neck stiffness. A CT demonstrates blood in the subarachnoid space. Which of the following is the next most common symptom associated with SAH?

(a) Seizures

(b) Altered consciousness

(c) Focal neurology

(d) Subhyaloid haemorrhages

(e) Vertigo

Answer 10

(c) Focal neurology

There are focal neurological signs in approximately one third of cases of subarachnoid haemorrhage. Seizures occur in 6-:-16% of cases, altered consciousness in 2%, subhyaloid haemorrhages in 10%; vertigo is a recognised feature but rare.

Question 11

37 A middle aged man is found collapsed, with a GCS pf 5/15. A CT head (performed without i. v. contrast medium administration) reveals increased attenuation material within the basal cisterns, superior cerebellar cistern and cortical sulci. Which of the following conditions is not associated with the likely underlying diagnosis?

(a) Intra-cerebral arterio-venous malformation

(b) Eclampsia

(c) Hypertension

(d) MELAS

(e) Tumour

Answer 11

(d) MELAS

Subarachnoid haemorrhage is described. It is associated with a ruptured aneurysm1ir 70% of cases, and an AVM in 10%. Other causes include: hypertensibn, tumour haemorrhage, embolic infarction, blood dyscrasia, eclampsia, and intracranial infection. SAH is cryptogenic in approximately 5%.

Question 12

45 A young patient suffers seemingly trivial trauma to the neck and subsequently presents with acute onset focal weakness. Arterial dissection is suspected. Regarding arterial dissection of the head and neck, which of the following is incorrect?

(a) Dissection of the internal carotid artery is more common than vertebral. artery dissection

(b) Vertebral dissection is commonest at the C4-5 level

(c) Stroke occurs earlier with intracranial, rather than extracranial dissection

(d) Periarterial rim of high signal can be seen on T1 W

(e) Neck pain and headache are present in the majority

Answer 12

(b) Vertebral dissection is commonest at the C4-5 level

Vertebral dissection is most common at the C1-2 level.

Stroke may be delayed for several hours in extracranial dissections.

The periarterial rim of high signal on T1 W represents intramural haematoma.

Question 13

@# 1 A young man presents with a thunderclap headache. A CT examination is performed. Sub-arachnoid blood is seen with a localised clot which has a maximum thickness of 2 mm. No intraventricular nor parenchymal blood is seen. What is the Fisher Grade?

(a) Grade 0

(b) Grade I

(c) Grade II

(d) Grade Ill

(e) Grade IV

Answer 13

(d) Grade Ill

The Fisher scale is useful in communicating the description of SAH.

Grade 1: no haemorrhage evident,

grade 2: SAH < 1 mm,

grade 3: SAH > 1 mm,

grade 4: associated intra-ventricular haemorrhage or parenchymal extension.

Question 14

16 A patient with a known intracerebral neoplasm suddenly deteriorates. A CT head demonstrates enlargement of Lt CPA cistern and new areas of high atten. in ant. midbrain. Which type of cerebral herniation is most likely?

(a) Subfalcine

(b) Transtentorial

(c) Transcalvarial

(d) Tonsillar

(e) Transalar

Answer 14

(b) Transtentorial

Descending transtentorial (or uncal) herniation is associated with: effacement of the ipsilateral suprasellar cistern, enlargement of the ipsilateral CPA cistern, Duret haemorrhages in the midbrain (which would feature as regions of high attenuation), and PCA ischemia.

Question 15

39 A young man suffers a severe head injury and a CT head identifies a significant haematoma. Which feature would be more suggestive of an extra-dural, rather than sub-dural haematoma?

(a) High attenuation

(b) Absence of skull fracture

(c) Peripheral enhancement

(d) Mixed density

(e) Crosses the tentorium cerebelli

Answer 15

(e) Crosses the tentorium cerebelli

The ability to cross dural reflections, such as the falx and tentorium cerebelli, places the haematoma in the extra-dural, rather than subdural space.

Question 16

43 Which of the following imaging features would not support the diagnosis of diffuse axonal injury?

(a) Multiple ovoid lesions ranging in size from 5-15 mm

(b) Involvement at the grey-white interface

(c) Lesions seen more prominently on CT than MR imaging

(d) On CT imaging, lesions demonstrate a low attenuation margin

(e) Sparing of grey matter

Answer 16

(c) Lesions seen more prominently on CT than MR imaging

The typical lesions of diffuse axonal injury are seen more prominently on MR than CT imaging.
Currie

Question 17

@# 12. Which of the following best represents the decline in positive CT findings for a clinically suspected subarachnoid haemorrhage from scanning at 12 hours post-ictus to 3 days post-ictus?

a. 90% positive at 12 hours to 70% positive at 3 days

b. 90% positive at 12 hours to 60% positive at 3 days

c. 98% positive at 12 hours to 90% positive at 3 days

d. 98% positive at 12 hours to 75% positive at 3 days

e. 90% positive at 12 hours to 50% positive at 3 days

Answer 17

12.d. 98% positive at 12 hours to 75% positive at 3 days

Question 18

19. A 72 year old man from a nursing home presents to the accident and emergency department. Nurses have noticed increasing confusion following a fall six days earlier. His inflammatory markers are normal. A non-contrast CT scan of the head demonstrates a crescent-shaped collection in the left fronto-parietal region. The collection is isodense to CSF and there is no midline shift, nor hydrocephalus. On T1-weighted MR imaging the lesion is isointense to CSF. The most likely diagnosis is:

a. Subdural hygroma

b. Brain atrophy

c. Subdural empyema

d. Chronic subdural haematoma

e. Enlarged subarachnoid space

Answer 18

19. a. Subdural hygroma

This is a traumatic subdural effusion which shows up as a localised CSF-fluid collection within the subdural space.

They present in the elderly or in young children usually 6–30 days following trauma.

The majority are asymptomatic but patients may present with increasing confusion or headaches.

They are devoid of blood products on imaging, unlike chronic subdural haematomas.

Subdural haematomas are also more likely to cause effacement of the ventricular system and loss of the normal sulci-gyral pattern.

Normal inflammatory markers and lack of pyrexia lessen the probability of an empyema.

Question 19

(MSK) 25. A 75 year old man who is on warfarin for atrial fibrillation is involved in a high-speed road traffic accident in which he sustains a head injury. He lost consciousness at the scene. On arrival at the A&E department his GCS is 15. He has no other injuries. According to NICE guidelines, his management should include the following:

a. Skull radiograph

b. No immediate imaging but admission for regular neurological observations

c. CT head

d. Skull radiograph followed by CT head

e. MRI head

Answer 19

25. c. CT head

According to NICE guidance he should undergo CT head and the investigation should be performed within the hour following referral. The fact he is anticoagulated, over 65 and experienced a loss of consciousness would all be factors in warranting an urgent CT head.

Question 20

31. A ten year old girl attends the emergency department after a head injury. You are requested to perform an acute CT scan of her head. According to NICE guidelines for head injury, which one of the following criteria alone does not warrant an acute head CT scan?

a. Retrograde amnesia lasting >5 minutes

b. Antegrade amnesia lasting >5 minutes

c. More than one episode of vomiting

d. CSF otorrhea

e. Abnormal drowsiness

Answer 20

31. c. More than one episode of vomiting

NICE head injury guidelines for children (under 16) advocate CT head imaging if there are three or more discrete episodes of vomiting. All of the other criteria listed are requisites for acute CT head scanning. CSF otorrhoea implies basal skull fracture. Other criteria include:
_ When the head injury occurs as a result of a dangerous mechanism (high-speed road traffic accident either as a pedestrian, cyclist or vehicle occupant, fall from over three metres, high speed injury from a projectile or an object).
_ Age > one year; GCS <14 on assessment in the emergency department.
_ Age > one year: GCS (paediatric) <15 on assessment in the emergency department.

Question 21

QUESTION 19
A 40-year-old motorcyclist is brought to the Emergency Department following a road traffic accident. His GCS at the scene was 9 but has now dropped to 6. His CT head reveals multiple small hyperdense lesions at the corticomedullary junction and in both basal ganglia. His condition does not improve and his GCS drops further to 4. He remains in hospital and an MRI scan a month after his admission shows low signal foci on T2w images at CM junction and in the basal ganglia. What is the most likely diagnosis?

A Diffuse axonal injury

B Extensive subarachnoid haemorrhage

C Hypoxic cerebral injury

D Multiple haemorrhagic contusions

E Venous infarction

Answer 21

A Diffuse axonal injury

Diffuse axonal injury occurs in shearing injuries as a result of sudden rotation, acceleration or deceleration. Typical findings include high attenuation on CT at the corticomedullary junction and in the corpus callosum, internal capsule and brainstem due to microvascular haemorrhages. However, CT may be normal and MRI (especially gradient echo sequences) is more sensitive. Cerebral atrophy is a late feature.

Question 22

QUESTION 79
A 37-year-old woman is involved in a road traffic accident and sustains a severe head injury. Her CT head shows acute blood within the extradural, subdural and subarachnoid spaces. Which one of the following statements is true regarding extradural haematomas?

A They are crescentic in shape.

B They are commonest in the temporoparietal region.

C They are rarely associated with a skull fracture.

D They are usually due to laceration of the middle cerebral artery.

E They commonly cross the cranial sutures.

Answer 22

B They are commonest in the temporoparietal region.

Question 23

29. A 27-year-old female patient undergoes urgent neuroimaging following loss of consciousness as a result of an RTA. CT is unremarkable. MRI reveals multiple small areas of increased signal on T2WI in the white matter near the grey–white matter junction within the frontal and temporal lobes. In the same locations, DWI reveals areas of increased signal on the B1000 image and reduced signal on the ADC map. What is the most likely diagnosis?

A. Subarachnoid haemorrhage.

B. Extradural haematoma.

C. Subdural haematoma.

D. Hypoxic brain injury.

E. Diffuse axonal injury.

Answer 23

29. E. Diffuse axonal injury (DAI).

CT is initially often normal (up to 80% of cases) in DAI. If positive, it may reveal small low attenuation foci (oedema) or high attenuation foci of petechial haemorrhage. The gray/white matter interface of the frontotemporal lobes, corpus callosum (especially the splenium), and brainstem are the most commonly involved sites in DAI. MRI is much more sensitive and is the investigation of choice.
The signal on MRI depends on the age of the lesion and whether haemorrhage is present, but classically hyperintense foci on T2WI sequences are seen acutely. In the more chronic phase, the lesions may only be detected as hypointense foci at characteristic locations on GE sequences: this appearance may remain for years. DWI reveals hyperintense foci of restricted diffusion on B1000 images, with corresponding low signal on the ADC map. The findings on DWI are easily distinguishable from extradural haematoma/subarachnoid haemorrhage/subdural haematoma/ generalized oedema, which are discussed in other questions in this chapter.

Question 24

30. A 34-year-old man undergoes MRI of brain after admission for head trauma. Which of the following sequences is most sensitive for subarachnoid haemorrhage?

A. T1WI.

B. T1WI with fat saturation.

C. T2WI.

D. FLAIR.

E. Proton density.

Answer 24

30. D. FLAIR.

Although CT is generally used for investigating acute subarachnoid haemorrhage (SAH), FLAIR sequence on MRI has been suggested as being as sensitive as or more sensitive than CT.

It is particularly useful in regions where CT may be limited due to beam hardening artefacts or if there is a very small amount of blood.

Acute SAH appears as high intensity on FLAIR within the cisterns and sulci.

Subacute SAH may be better appreciated on MRI because of its high signal intensity when the blood is isointense to CSF on CT. SAH differs from intra-parenchymal haemorrhage in that the mix of blood with high-oxygen tension CSF delays generation of paramagnetic deoxyhaemoglobin, and oxyhaemoglobin remains present longer than in intra-parenchymal haemorrhage.

This contributes to continued T2 prolongation.

Beware that there are other pathological (meningitis, leptomeningeal metastases, acute stroke, fat-containing tumour/dermoid rupture) and benign (artefact, supplemental oxygenation) causes of FLAIR hyperintensity in the subarachnoid space.

Chronic haemorrhage from SAH is best detected on GE sequences, resulting in marked subarachnoid low signal (the blooming of superfi cial siderosis).

Question 25

32. A 27-year-old man suffers a head injury. A CT brain is performed. Which of the following features favours a subdural haematoma (SDH) over an extradural haematoma (EDH)?

A. The haematoma measures 50 HU.

B. The presence of a temporal skull fracture.

C. The haematoma crosses the midline over the falx.

D. The collection has a biconvex configuration.

E. The haematoma crosses sutures.

Answer 25

32. E. The haematoma crosses sutures.

An SDH will cross suture lines and may extend over the whole cerebral hemisphere; an EDH will not. Only an EDH can cross the midline, and this usually occurs at the vertex in the setting of a venous EDH. EDHs are more usually arterial bleeds and associated with temporal skull fractures, which disrupt the adjacent middle meningeal artery. The latter are typically biconvex; SDHs are typically lentiform in shape. Both measure 50–60 HU if acute. Chronic SDHs may be iso- or hypodense to brain, although anaemia or clotting disorders can produce a similar appearance. EDH is a neurosurgical emergency more so than SDH because of the potential lucent period followed by sudden deterioration as arterial bleeding continues after having stripped the dura from the inner table of the skull.

Question 26

41 A 45-year-old female fell down a flight of stairs under the influence of alcohol and presented to the Emergency Department with a deteriorating GCS. A non-contrast CT revealed a 13-mm deep left temporoparietal lenticular haematoma. What is the most likely source of the bleed?

a Middle meningeal artery

b Internal cerebral veins

C Bridging cortical veins

d Choroidal arteries

e Vein of Labbe

Answer 26

41 Answer A: Middle meningeal artery

Extradural haematomas (EDH) are biconvex/lentiform in shape and result from a lacerated middle meningeal artery/dural sinus in 70-85 %.

Associated fractures are seen in 85-95%. EDH occur between the skull and the dura and cross dural attachments, but not sutures.

Subdural haematomas are crescentic and are generally caused by stretching/tearing of bridging cortical veins.

They occur between the dura and arachnoid and cross sutures but not dural attachments.

Question 27

42 A 46-year-old motorcyclist was involved in a high-speed RTA. On arrival of the paramedics, the GCS was recorded as 4/15 and the patient was intubated at the site of injury. An emergency noncontrast CT showed multiple subtle petechial haemorrhages characteristic of diffuse axonal injury. What is the most likely site of the petechial haemorrhage?

a Insular ribbon

b Watershed areas

C Periventricular white matter

d Grey-white matter junction

e Cerebellum

Answer 27

42 Answer D: Grey-white matter junction

Diffuse axonal injury (DAI) occurs in severe trauma as a result of shearing stress along the course of the white matter tracts especially at the grey-white matter junction. The injury is usually microscopic and initial CTs are usually normal despite profound clinical impairment. Acute DAI may also be seen as small petechial haemorrhages at the grey-white matter junction (67 %), internal/external capsule, corona radiata, corpus callosum (21 %) and brainstem. MR features depend on the age of the haemorrhage. Prognosis is poor.

Question 28

14 A 42-year-old smoker presented with right arm weakness and left-sided ptosis with a constricted left pupil. A contrast-enhanced CT of his neck was performed. What is the most likely appearance of the carotid arteries?

a Normal appearance on left

b Luminal narrowing on left

C Double lumen sign on right

d Double lumen sign on left

e Luminal narrowing on right

Answer 28

14 Answer B: Luminal narrowing on left

The most common site of an extracranial internal carotid artery dissection is the segment of vessel just distal to the carotid bifurcation.

The most common finding on angiography is that of a tapered luminal narrowing and associated enlargement of the diameter of the dissected vessel.

If there is a severe stenosis, then a `string’ sign can be seen.

An intimal flap is frequently not identified in internal carotid artery dissections and therefore the characteristic `double lumen’ sign is not usually seen.

On CT the eccentric rim of intramural haematoma does not usually enhance but on MRI it can display increased signal intensity on T1-weighted images as a result of the methaemoglobin content, although fatsuppression imaging is needed in order to differentiate the intramural haematoma from surrounding periarterial fat.

The rim of intramural haematoma may not exhibit hyperintensity in the first few days after dissection as it contains primarily deoxyhaemoglobin and will therefore be isointense with the surrounding muscle.

Partial ptosis and constricted pupil are components of Horner’s syndrome due to interruption in the sympathetic nerve supply.

Question 29

(MSK) 25 An elderly man on warfarin treatment for atrial fibrillation is found at the bottom of a flight of 10 stairs with widespread bruising to his arms and face. On transfer to the Emergency Department he was confused but is otherwise neurologically intact, moving all four limbs and opening his eyes spontaneously. What is the most appropriate investigation?

a Carotid Doppler

b Urgent CT head

c Echocardiogram

d Chest X-ray

e Skull X-ray

Answer 29

25 Answer B: CT head

There is no scope for a skull X-ray in head trauma. An urgent CT head is mandatory and can delineate fractures and acute haemorrhage very well.
National Institute for Clinical Excellence. Investigation for Clinically Important Brain Injury:
NICE guideline 56. London: NIHCE; 2007. www.nice.org/guidance/ CG056
Selection of adults for CT scan: urgent scan if any of the following (results within 1 hour)
* GCS<13 when first assessed or GCS<15 two hours after injury
* Suspected open or depressed skull fracture
* Signs of base of skull fracture
* Post-traumatic seizure
* Focal neurological deficit
* >1 episode of vomiting
* Coagulopathy + any amnesia or LOC since injury
A CT scan is also recommended (within eight hours of injury) if there is either more than 30 minutes of amnesia of events before impact or any amnesia or LOC since injury if one of the following applies: Aged >_65 years, coagulopathy or on warfarin or a dangerous mechanism of injury (i.e. RTA as pedestrian, RTA - ejected from car, fall >1 in or >5 stairs).
Selection of children (under 16 years) for CT scan: urgent scan if any of the following:
* witnessed loss of consciousness >5 minutes
* amnesia (antegrade or retrograde) >5 minutes
* Abnormal drowsiness
* >_3 Discrete episodes of vomiting
* clinical suspicion of NAI
* post-traumatic seizure (no PMH epilepsy)
* GCS <14 in emergency room
* (paediatric GCS<15 if aged <1)
* suspected open or depressed skull fracture or tense fontanelle
* signs of base of skull fracture
* focal neurological deficit
* aged <1 - bruise, swelling or laceration on head >5 cm
* dangerous mechanism of injury (high speed RTA, fall from >3 in, high speed projectile).

Question 30

38 A young male presented with symptoms of neck pain and ipsilateral headache following a weekend of rock climbing. Signs of ipsilateral Horner’s syndrome were also elicited. Following an MRI, a diagnosis of carotid artery dissection was made. Which segment of the carotid artery is most likely to be involved?

a Cervical segment

b Petrous segment

C Lacerum segment

d Cavernous segment

e Supraclinoid segment

Answer 30

38 Answer A: Cervical segment

Carotid artery dissection is known to occur after seemingly trivial trauma. Partial Homer’s is present in less than 50% of patients and ipsilateral persistent headache is common. It accounts for up to 25% of strokes in the young and middle-aged patients. The extracranial portion is more commonly involved (cervical ICA at C1-C2 - 60%); dissection of the intracranial portion is relatively rare as the skull base absorbs most of the force.

Question 31

28. A 28-year-old unconscious man was admitted to the Accident & Emergency Department after a motorcycle accident. He briefly regained consciousness and then started to decline again. CT of the head shows a fracture of his right parietal bone over a lentiform extra-axial haematoma with midline shift. What is the most likely diagnosis?

(a) Subdural haematoma

(b) Extradural haematoma

(c) Subarachnoid haemorrhage

(d) Meningioma

(e) Intraparenchymal bleed

Answer 31

28. (b) Extradural haematoma

Classically an extradural haematoma is seen as a lentiform/biconvex hyperdense collection bounded by cranial sutures and associated with skull fracture. The collection may be heterogenous if active bleeding is occurring.

Question 32

18. Concerning the differences between cortical contusions and diffuse axonal injury (DAI): (T/F)

(a) Patients with cortical contusions are much less likely to have had loss of consciousness.

(b) Patients with cortical contusions usually have a better prognosis.

(c) Cortical contusions are more commonly haemorrhagic than DAI.

(d) CT is the best modality to diagnose acute DAI.

(e) Most patients with DAI suffer immediate loss of consciousness.

Answer 32

Answers:
(a) Correct
(b) Correct
(c) Correct
(d) Not correct
(e) Correct

Explanation:
Diffuse axonal injury are seen much better on MRI than CT. On MRI diffusion weighted images and susceptibility weighted images are most