Central Nervous System and Head & Neck - Warm Up

Question 1

@# 1. The following are causes of a ‘hair-on-end’ appearance of the skull vault:
a) Haemangioma
b) Thalassaemia major
c) Hereditary spherocytosis
d) Rickets
e) Sickle cell anaemia

Answer 1

1.
a. True
b) True
c) True
d) False
e) True

Question 2

@# 2. Secondary metastases to the brain:
a) Are the commonest cause of brain tumour in adults
b) Are usually multiple
c) Are supratentorial in 75-90%
d) Are usually hypodense on non-contrast CT
e) Are almost always high signal on T2 weighted MRI

Answer 2

a) False - approximately two thirds of brain tumours are primary tumours, whereas one third
are secondary metastases
b) True
c) True - however, from renal cell carcinoma are usually located in the posterior fossa
d) True - however, haemorrhagic metastases may be hyperdense precontrast
e) False - variable signal intensity on T2 weighted images

Question 3

3. Arachnoid cyst:
   a) Is also known as leptomeningeal cyst
   b) Most commonly occurs in the middle cranial fossa
   c) One third are found in the posterior fossa
   d) Can cause erosion of the calvarium
   e) Can calcify

Answer 3

3.
a) True - this is the acquired form, usually secondary to trauma or surgery
b) True - 50%
c) True
d) True - the inner table
e) False

Question 4

@# 4. Concerning the submandibular space:
a) Anteriorly there is free communication between the submandibular space and the
sublingual space
b) The superficial lobe of the submandibular gland lies inferolateral to mylohyoid
c) Intraglandular ducts are seen as linear hypoechoic structures on ultrasound
d) As with the parotid gland, normal lymph nodes are found within the submandibular gland
e) Stenson’s duct exits in the floor of the mouth at the base of the frenulum

Answer 4

4.
a) False - posteriorly
b) True
c) False - linear hyperechoic structures
d) False - due to early glandular encapsulation normal lymph nodes are not found within the
submandibular gland
e) False - Wharton’s duct

Question 5

5. Pyogenic brain abscesses:
   a) Most commonly occur secondary to a generalised septicaemia
   b) Typically occur at the corticomedullary junction
   c) Are more common in the occipital lobes than the frontal lobes
   d) The most common causative organism is Staphylococcus Spp.
   e) On CT have a smooth regular wall with relative thinning of the lateral wall

Answer 5

5.
a) False - 32% occur due to generalised septicaemia from for example, a lung abscess or
pneumonia. However, 41 % occur secondary to extension from paranasal sinus infection
b) True
c) False
d) False - anaerobic Streptococcus Spp.
c) False - relative thinning of medial wall due to poorer blood supply of white matter. This
predisposes to rupture of the abscess medially into the ventricular system

Question 6

@# 6. The following cause wide cranial sutures in children:
a) Subdural haematoma
b) Hypophosphatasia
c) Lead intoxication
d) Lymphoma
e) Neuroblastoma

Answer 6

6.
a) True - only seen in children less than 10 years of age
b) True
c) True
d) True
e) True - also +/- sunray spiculation

Question 7

@# 7. Regarding subarachnoid haemorrhage:
a) It occurs secondary to arteriovenous malformation in 10% of cases
b) It is associated with subdural haemorrhage in 20% of cases
c) 15-20% of patients will have multiple aneurysms
d) Cerebral vasospasm is maximal from 48 to 72 hours after the event
e) MRI is the best modality for detecting early subarachnoid haemorrhage

Answer 7

7.
a) True
b) False - 5%
c) True
d) False - 5-17 days
e) False - may not be seen on MRI for 48 hours. When haemorrhage occurs, oxyHb is
converted to deoxyHb at a rate depending on oxygen tension and local pH. This can be
delayed when oxygen- containing CSF surrounds the haemorrhage. This is why it is
difficult to detect subarachnoid haemorrhage on MRI

Question 8

8. The following are true concerning MRI:
   a) The magnet is cooled with liquid helium
   b) The shim coil lies within the gradient coil
   c) Surface coils improve signal-to-noise ratio
   d) Gadolinium is contraindicated in pregnancy
   e) Gadolinium is contraindicated in patients with haemolytic anaemia

Answer 8

8.
a) True
b) False - outside it
c) True
d) True
e) True

Question 9

9. The following are usually hyperdense to normal brain on CT:
   a) Medulloblastoma
   b) Metastases
   c) Acoustic neuroma
   d) Epidermoid
   e) Meningioma

Answer 9

9.
a) True - in 80%
b) False - usually hypodense
c) False - usually isodense but enhances avidly
d) False - hypodense
e) True

Question 10

@# 10. Klippel-Feil syndrome is associated with the following:
a) Sprengel’s deformity
b) Syringomyelia
c) Cranial asymmetry
d) Low posterior hair line
e) Schmorl nodes

Answer 10

10.
a) True - in 25-40% - Sprengel’s Deformity is a congenital condition characterized by a small and undescended scapula often associated with scapular winging and scapular hypoplasia.

b) True - Syringomyelia is a neurological disorder in which a fluid-filled cyst (syrinx) forms within the spinal cord.

c) True

d) True

e) False

Question 11

@# 11. Chemodectomas:
a) Are derived from chemoreceptor cells
b) Are bilateral in 20% of cases
c) Normally arise from the adventitial layer of the common carotid artery
d) Normally cause splaying of the internal and external carotid arteries
e) Normally cause narrowing of the internal and external carotid arteries

Answer 11

11.
a) False - chemodectoma is a misnomer
b) False - 5%
c) True
d) True
e) False

Question 12

12. Concerning trauma to the skull:
    a) Temporal bone fractures are most commonly transverse
    b) Longitudinal temporal bone fractures often cause a sensorineural hearing loss
    c) Transverse temporal bone fractures cause facial palsy in 30-50% of cases
    d) Skull fracture is seen in 90% of cases of extradural haematomas
    e) Subdural haematomas commonly cause diffuse swelling of the underlying hemisphere

Answer 12

12.
a) False - 75% are longitudinal
b) False - conductive hearing loss
c) True - this is often complete
d) True
e) True - therefore causing more mass effect than would be expected

Question 13

@# 13. Concerning orbital mass lesions:
a) 60-80% of children with retinoblastoma have bilateral tumours
b) On MRI, retinoblastoma usually enhances following intravenous gadolinium
c) Rhabdomyosarcoma of the orbit presents with rapid onset proptosis and visual loss
d) Inflammatory orbital pseudotumour involves the muscle tendons
e) 50% of patients with optic nerve glioma have neurofibromatosis Type 1

Answer 13

13.
a) False - 20-40%, and this is most often the autosomal dominant type
b) True
c) False - vision is preserved
d) True
e) False - 25%. 15% of patients with neurofibromatosis Type 1 have optic nerve glioma

Question 14

@# 14. The following cause basal ganglia calcification:
a) Pseudopseudohypoparathyroidism
b) Hyperparathyroidism
c) Carbon monoxide poisoning
d) Toxoplasmosis
e) Cockayne’s syndrome

Answer 14

14.
a) True
b) True
c) True
d) True
e) True - autosomal recessive demyelinating disease associated with deafness and dwarfism

Question 15

@# 15. Regarding cerebral interventional procedures:
a) An 8-French catheter is normally used
b) The right brachial artery is usually catheterised
c) Most interventional procedures are better done under local anaesthetic with mild sedation
d) Guidewires may safely remain within a catheter for up to 5 minutes without withdrawal
and flushing
e) Injection of 25 ml of contrast by hand in about 1.5 seconds is safe in the internal carotid
artery

Answer 15

15.
a) False - 5 or 6-French
b) False - right femoral artery
c) False - general anaesthetic is best for cerebral interventional procedures
d) False - up to 1 minute
e) False - 7 ml

Question 16

@# 16. The following are true of MRI:
a) The net magnetisation factor rotates at the Larmor frequency
b) The Larmor frequency is 42.6 MHz at a magnetic field strength of 1.5 Tesla
c) The repetition time controls the amount of T1 weighting
d) T1 weighted images have an echo time less than 80 ms
e) T1 recovery is also called longitudinal relaxation

Answer 16

16. 16
    a) True
    b) False - 63.9 MHz
    c) True
    d) False - less than 20 ms
    e) True

Question 17

@# 17. Multiple wormian bones are seen in the following:
a) Down’s syndrome
b) Osteogenesis imperfecta
c) Hyperphosphatasia
d) Osteopetrosis
e) Pyknodysostosis

Answer 17

17.
a) True
b) True
c) False - hypophosphatasia
d) False
e) True

Question 18

18. 18 Concerning pineal region masses:
    a) Pineoblastomas are categorised as part of the primitive neuroectodermal tumour group
    b) Pineoblastomas usually show poor enhancement
    c) Pineal germinomas are associated with Parinaud’s syndrome
    d) Germinomas are 10 times more common in males than females
    e) Germinomas are hypodense on unenhanced CT

Answer 18

18.
a) True - they are similar to medulloblastomas
b) False - avidly enhance
c) True - paralysis of upward gaze
d) True
e) False - isodense or hyperdense

Question 19

@# 19. A generalised increase in skull vault density is seen in the following:
a) Fibrous dysplasia
b) Fluorosis
c) Phenytoin therapy
d) Craniometaphyseal dysplasia
e) Myelofibrosis

Answer 19

19.
a) True
b) True - calcification of muscle attachments is also seen
c) True
d) True - associated with metaphyseal splaying of the long bones
e) True - the spleen is greatly enlarged

Question 20

@# 20. Concerning pituitary adenomas:
a) Hormonally active pituitary adenomas are usually microadenomas
b) The normal posterior pituitary is hyperintense to grey matter on T1 weighted images
c) Prolactinoma is the most commonly encountered pituitary adenoma
d) They are five times more common than craniopharyngiomas
e) Immediately after injection of gadolinium, pituitary adenomas remain hypointense to grey
matter on T1 weighted imaging

Answer 20

20.
a) True - 75% of pituitary adenomas are hormonally active
b) True
c) True
d) True
e) True - they become isointense or hyperintense after half an hour

Question 21

@# 21. Causes of thickening of the skull calvarium include:
a) Acromegaly
b) Sickle cell anaemia
c) Rickets
d) Phenytoin
e) Hyperparathyroidism

Answer 21

21.
a) True - also causes an enlarged sella
b) True - due to extramedullary haematopoesis
c) False - causes thinning of skull
d) True
e) False - causes thinning of skull

Question 22

22. Regarding meningiomas:
    a) 1-4% are ‘malignant’
    b) Approximately 50% are parasagittal
    c) The majority enhance homogenously
    d) 40-60% calcify
    e) The dural ‘tail’ sign is specific for meningioma

Answer 22

22.
a) True - i.e. invade local brain parenchyma
b) True
c) True - 10% have low attenuation areas representing necrosis
d) False - 20%
e) False - seen in 60% of meningiomas but it is not specific

Question 23

@# 23. Concerning haemangioblastoma:
a) It is the commonest primary posterior fossa tumour in adults
b) Most are associated with von Hippel-Lindau syndrome
c) Calcification occurs in 20-30% of cases
d) It usually presents as a well defined cystic mass
e) Flow void may be seen on MRI

Answer 23

23.
a) True
b) False - 4-20% are associated with von Hippel-Lindau syndrome
c) False - calcification is very rare
d) True - in 40% presents as solid mass
e) True - from the vascular pedicle of the mural nodule associated with cystic
haemangioblastoma

Question 24

24. The following are true concerning central nervous system (CNS) infections:
    a) Fungal infections present as meningitis more commonly than granuloma or abscess
    b) Histoplasmosis tends to occur in the immunosuppressed
    c) Mucormycosis tends to occur in the immunosuppressed
    d) Cryptococcosis is the commonest CNS fungal infection
    e) CT of the brain in cryptococcus infection is usually normal

Answer 24

24.
a) True
b) False - endemic
c) True
d) True
e) True - reflecting mild meningeal involvement

Question 25

25. 25 Regarding differentiation between epidermoids and dermoids of the brain:
    a) Both are formed due to enclosure of ectodermal elements when the neural tube closes
    b) Epidermoids are more common
    c) Epidermoids more closely resemble cerebrospinal fluid on MRI
    d) Epidermoids may become malignant
    e) Fat-fluid level on imaging is highly suggestive of dermoids

Answer 25

25.
a) True
b) True
c) True
d) False - both are benign and slow growing
e) True

Question 26

@# 26. Concerning epiloia (tuberous sclerosis):
a) The classic triad of adenoma sebaceum, seizures and mental retardation occurs in 50% of
cases
b) Subependymal giant cell astrocytoma typically occurs posteriorly in the 3rd ventricle
c) Heterotopic grey matter islands in white matter occur in the majority of patients
d) Most patients die from complications of renal involvement
e) It is associated with lymphangioleiomyomatosis

Answer 26

26.
a) False - 30%
b) False - it occurs anteriorly in the region of the foramen of Monro
c) True - 93%
d) True - 75% of patients die from complications of renal failure by 20 years of age
e) True - in 1 % of cases

Question 27

@# 27. The following are true of colloid cysts:
a) They usually arise from the lateral ventricles
b) They typically obstruct the foramen of Monro
c) They are hyperdense on unenhanced CT in 60-80% of cases
d) They are usually high signal on T1 weighted MRI
e) They are associated with the Brun phenomenon

Answer 27

27.
a) False - typically 3rd ventricle
b) True
c) False - 50% hyperdense. 50% isodense
d) True
e) True - acute severe headache reproduced by patient tilting head forward. In this position
the cyst may obstruct the foramen of Monro

Question 28

28. Concerning parasitic CNS infections:
    a) The brain is involved in 10-20% of cases of hydatid disease
    b) Most patients with cysticercosis develop seizures
    c) Hydatid disease of the brain mostly involves the posterior fossa
    d) Toxoplasmosis is often confused with CNS lymphoma
    e) Grape-like clustered lesions in the basal cisterns are seen in cysticercosis

Answer 28

28.
a) False – 1 - 4%
b) True - 90%
c) False - usually supratentorial CSF-density lesions in middle cerebral artery territory
d) True
e) True

Question 29

29. Concerning cerebellopontine angle masses:
    a) Meningiomas are the second commonest cerebellopontine angle mass
    b) Meningiomas are typically brighter on T2 weighted MRI than T1
    c) Meningiomas commonly cause expansion of the internal auditory canal
    d) Epidermoids have the same signal as cerebrospinal fluid on MRI
    e) Acoustic neuroma usually enhance poorly on post-contrast scans

Answer 29

29.
a) True
b) False - less bright on T2 weighted MRI
c) False - usually no expansion
d) True
e) False - enhances avidly

Question 30

@# 30. A small pituitary fossa is caused by the following:
a) Radiotherapy as a child
b) Dystrophia myotonica
c) Nelson’s syndrome
d) Hypopituitarism
e) Achondroplasia

Answer 30

30.
a) True
b) True - hereditary condition of early adult life characterised by frontal baldness, cataracts,
testicular atrophy and thickening of the skull with large frontal sinuses
c) False - this is seen post-adrenalectomy for Cushing’s syndrome and causes an expanded
pituitary fossa
d) True
e) False - this causes a J-shaped sella

Question 31

@# 31. Indications for MRI in stroke include:
a) Normal CT
b) Investigation of venous thrombosis
c) Investigation of arterial dissection
d) Supratentorial infarcts
e) Detection of reversible ischaemia

Answer 31

31.
a) True - MRI is more sensitive than CT for the diagnosis of early ishaemic stroke and small
vascular insults
b) True - loss of the normal flow void within a dural sinus or cerebral vein may indicate
thrombosis
c) True
d) False - however, MRI is vastly superior to CT in evaluation of the posterior fossa
e) True

Question 32

@# 32. Allowing are true of the signal characteristics of intracerebral haematoma on MRI:
a) In the first 12 hours the haematoma is high signal on T1 weighted images
b) Intracellular methaemoglobin is high signal on T2 weighted images
c) Extracellular methaemoglobin is low signal on T2 weighted images
d) Haemosiderin is low signal on T1 weighted images
e) Deoxyhaemoglobin is low signal on T2 weighted images

Answer 32

32.
a) False - intermediate signal intensity. At this stage it is bright on T2 weighted images due to
oxyhaemoglobin
b) False - low signal
c) False - high signal
d) True
e) True

Question 33

@# 33. Posterior scalloping of vertebral bodies is caused by the following:
a) Ependymoma
b) Acromegaly
c) Lipoma
d) Syringomyelia
e) Down’s syndrome

Answer 33

33.
a) True - especially of the filum terminale and conus
b) True
c) True
d) True - especially if the onset is before 30 years of age
e) False - but causes anterior scalloping of vertebral bodies

Question 34

@# 34. Concerning brain herniation:
a) Uncal herniation is the commonest type
b) Uncal herniation normally causes a ‘blown out’ pupil
c) Subfalcine herniation causes enlargement of the adjacent lateral ventricle
d) Uncal herniation causes infarction of the posterior cerebral artery
e) Transtentorial herniation causes infarction of the posterior inferior cerebellar artery

Answer 34

a) False - subfalcine herniation is the most common
b) True - due to compression of 3rd cranial nerve
c) False - compression of the adjacent lateral ventricle and enlargement of the contralateral
one due to obstruction at the level of the foramen of Monro
d) True
e) True

Question 35

@# 35. Concerning otosclerosis:
a) It usually presents in infancy
b) It is more common in females
c) Stapedial otosclerosis causes a progressive sensorineural hearing loss
d) A lucent halo is seen around the cochlea on CT in the late phase of cochlear otosclerosis
e) Cochlear otosclerosis is more commonly seen than stapedial otosclerosis

Answer 35

35.
a) False - adolescents and young adults
b) True
c) False - progressive conductive hearing loss
d) False - this is seen in the early phase. Later bony proliferation and sclerosis occur
e) False - cochlear otosclerosis 10-20%. Stapedial otosclerosis 80-90%

Question 36

@# 36. Concerning orbital anatomy:
a) The inferior orbital fissure communicates with the pterygopalatine fossa and the masticator
space
b) There are 7 extra-ocular muscles
c) All the extra-ocular muscles arise from a common fibrous ring, the annulus of Zinn
d) The ophthalmic artery lies inferior to the optic nerve in the optic foramen
e) The levator palpebrae superioris can easily be identified on MRI

Answer 36

36.
a) True
b) True - four rectus muscles comprise the muscle cone, the levator palpebrae superioris and
the inferior and superior oblique muscles
c) False - all except inferior oblique muscle
d) True
e) False - with the superior rectus muscle is often referred to as the superior muscle complex

Question 37

37. Concerning the differences between cortical contusions and diffuse axonal injury (DAI):
    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 37

37.
a) True
b) True
c) True
d) False - much better seen on MRI than CT
e) True

Question 38

@# 38. Concerning non-accidental injury (NAI):
a) Skull fracture is the commonest NAI
b) Subdural haemorrhage is the commonest intracranial complication
c) Different ages of subdural haemorrhage seen on CT is pathognomonic of NAI
d) NAI-associated fracture usually affects the parietal bone
e) NAI accounts for half of deaths from head trauma in children less than 2 years of age

Answer 38

38.
a) False - second commonest after long bone fracture
b) True
c) False - they do have a propensity to rebleed if spontaneous
d) False - usually occipital
e) False - 80%

Question 39

@# 39. Concerning brain infarction:
a) Peak time for haemorrhagic transformation is 3-5 days post-infarct
b) Maximal brain swelling is seen on imaging on days 3-7 post-infarct
c) Gyral enhancement peaks from days 7-14 on CT
d) The hyperdense artery sign is usually seen within the first 2 hours post-infarct
e) The insular ribbon sign is usually seen within the first 2 hours post-infarct

Answer 39

39.
a) False - 1-2 weeks post-infarct
b) True
c) True
d) False - at 2-6 hours
e) False - at 2-6 hours

Question 40

@# 40. Regarding Fong disease:
a) It is an autosomal recessive disorder
b) Hypoplasia of the fingernails of the thumb and index finger is a feature
c) Bilateral posterior iliac horns are diagnostic, but only seen in one third of patients
d) It may be associated with recurrent dislocation of the patella
e) It is associated with renal osteodystrophy

Answer 40

40.
a) False - rare autosomal dominant disorder characterised by symmetrical meso- and
ectodermal anomalies
b) True - also spooning, splitting and ridging of fingernails
c) False - diagnostic but seen in 80% of patients
d) True - a feature is fragmentation, hypoplasia or absence of the patella
e) True

Question 41

@# 41. Concerning differences between primary CNS lymphoma and toxoplasmosis:
a) High signal on T2 weighted MRI favours lymphoma
b) Subependymal extension across the corpus callosum is more likely to occur in
toxoplasmosis
c) Toxoplasmosis is more frequently multiple
d) The lesions are usually smaller in lymphoma
e) Ring enhancement following contrast administration favours lymphoma

Answer 41

41.
a) False - toxoplasmosis
b) False
c) True
d) False
e) False - toxoplasmosis

Question 42

@# 42. Regarding contrast media:
a) Nephrotoxicity is predisposed in patients with multiple myeloma
b) Contrast potentiates blood clotting and platelet aggregation
c) Prophylactic haemodialysis lowers the risk of contrast media nephrotoxicity in patients
with pre-existing renal impairment
d) Intravenous infusion of 0.9% saline lowers the risk of contrast media nephrotoxicity in
patients with pre-existing renal impairment
e) Haemofiltration lowers the risk of contrast media nephrotoxicity in patients with preexisting
renal impairment

Answer 42

42.
a) True
b) False - it impairs it
c) False
d) True - (1 ml/kg body weight/hr) starting 4 hours before contrast injection and continuing
for at least 12 hours afterwards
e) True

Question 43

@# 43. Regarding osmotic myelinolysis:
a) It is caused by rapid correction of hypernatraemia
b) It affects the pons most commonly
c) MRI typically shows abnormality within 24 hours
d) On MRI there is hyperintensity on T2 weighted imaging
e) There is a good response to treatment

Answer 43

43.
a) False - caused by rapid correction or overcorrection of severe hyponatraemia. Usually
occurs in a comatose patient following prolonged intravenous fluid administration. 60-70%
occurs in chronic alcoholics
b) True
c) False - MRI becomes positive 1-2 weeks post-onset of symptoms
d) True
e) False - 5-10% survival rate beyond 6 months

Question 44

44. The following structures pass through the jugular foramen:
    a) Tenth cranial nerve
    b) Twelfth cranial nerve
    c) Internal jugular vein
    d) Superior petrosal sinus
    e) Ascending pharyngeal artery

Answer 44

44.
a) True
b) False - passes through its own canal, the hypoglossal canal
c) True
d) False - inferior petrosal sinus, which drains to the internal jugular vein
e) True

Question 45

@# 45. Cerebellar medulloblastoma:
a) Is the commonest paediatric brain tumour
b) Is more common in females
c) 75% of patients are less than 15 years of age
d) Calcification occurs in 40-50%
e) Is associated with basal cell carcinomas

Answer 45

45.
a) False - second commonest paediatric tumour. Is second only to astrocytoma. However, it is
the commonest paediatric posterior fossa tumour
b) False - more common in males
c) True - peak occurrences are from 4-8 years and 15-35 years of age
d) False - calcification occurs in up to 20% of patients. Cystic change or necrosis occurs in up
to 50%. Medulloblastomas are usually solid hyperdense masses on CT. On MRI they are
usually hypointense to grey matter on T1 weighting and have an extremely variable
appearance on T2 weighting. Oedema is almost always seen
e) True - high incidence of medulloblastoma is seen in children with Gorlin’s syndrome (basal
cell naevus syndrome)

Question 46

@# 46. The following are causes of intra-orbital calcification:
a) Haemangioma
b) Neurofibroma
c) Rhabdomyosarcoma
d) Coat’s disease
e) Adenocarcinoma of the lacrimal gland

Answer 46

46.
a) True - only rarely have calcified phleboliths
b) True - rarely
c) False
d) False - but indistinguishable from non-calcified retinoblastoma
e) True - may calcify

Question 47

@# 47. Glucagon:
a) Has an immediate onset of action
b) Is less potent than buscopan
c) Has a duration of action of 30 minutes
d) Is contraindicated in pregnant or breastfeeding women
e) Decreases peristalsis in the oesophagus

Answer 47

47.
a) False - onset is in one minute
b) False - more potent
c) False - 15 minutes
d) False - safe
e) False - however, buscopan does and is therefore preferred when assessing for oesophageal
varices

Question 48

@# 48. Regarding acquired immune deficiency syndrome (AIDS) of the CNS:
a) 60-80% of patients with AIDS will develop neurologic symptoms
b) The cortical grey matter is usually spared in HIV encephalitis
c) AIDS dementia complex occurs in approximately 40-50% of patients with AIDS
d) Progressive multifocal leukoencephalopathy does not occur in patients with normal
immunity
e) Primary CNS lymphoma is by far the commonest intracranial tumour in AIDS

Answer 48

48.
a) False - 40%
b) True
c) False - 7-15%
d) True
e) True

Question 49

@# 49. The following are true concerning chemical shift artefact in MRI:
a) It occurs in the frequency encoding direction
b) It increases with decreasing field strength
c) Increasing the bandwidth decreases the risk of chemical shift artefact
d) A dark line is seen adjacent to fat
e) Is used in diagnosing certain fat-containing lesions

Answer 49

49.
a) True
b) False - decreases
c) True - but this will decrease signal-to-noise ratio
d) True
e) True

Question 50

@# 50. Concerning vascular masses of the head and neck:
a) High-flow vascular malformations are normally treated with percutaneous sclerotherapy
b) Infantile haemangiomas usually warrant intervention
c) Pre-operative embolisation of juvenile angiofibroma reduces blood loss at surgery but may
predispose to recurrence
d) Extracranial external carotid artery aneurysms are most frequently secondary to
atherosclerotic disease
e) Haemangiopericytomas are benign tumours that may be located in the soft tissues of the
neck

Answer 50

50. 50
    a) False - intra-arterial embolisation with possible surgical excision
    b) False - they spontaneously involute. Although non-involuting cases are described in 5% of
    cases
    c) True
    d) False - most frequently secondary to trauma. But may also result from infection, congenital
    vascular anomalies and atherosclerotic disease
    e) False - may be malignant