Degenerative & Demyelinating diseases

Question 1

4. A 40-year-old with headache, confusion, seizures and visual disturbance has a CT showing low attenuation involving the cortex and subcortical white matter in both occipital lobes. Diffusion weighted MR shows no restriction. Which is the most likely diagnosis?

A. CADASIL

B. Bilateral occipital infarction

C. Posterior reversible encephalopathy syndrome

D. Sinus venous thrombosis

E. Hypoxic brain injury

Answer 1

C. Posterior reversible encephalopathy syndrome

These are typical imaging findings but the abnormalities are not always reversible or posterior.

Question 2

5.Which is the best answer describing neuro-imaging features of pre-eclampsia?

A. Most frequent abnormality on MR is high signal change on T2/fluid attenuated inversion recovery (FLAIR)

B. Lesions are in subcortical white matter only

C. Majority of lesions progress to infarction

D. Lesions are unilateral

E. Cerebral vasospasm is common in mild to moderate pre-eclampsia

Answer 2

A. Most frequent abnormality on MR is high signal change on T2/fluid attenuated inversion recovery (FLAIR)

Lesions are in deep and subcortical WM, pons and basilar territories.

They may be unilateral or bilateral and the majority are reversible although some can progress to infarction.

Vasospasm is uncommon in mild to moderate pre-eclampsia.

Question 3

7. Which of the following is a cause of cerebellar atrophy with cerebral atrophy?

A. Friedreich’s ataxia

B. Ataxic telangectasia

C. Phenytoin toxicity

D. Paraneoplastic atrophy

E. Senile brain atrophy

Answer 3

E. Senile brain atrophy

B-E are causes of cerebellar atrophy without cerebral atrophy.

Question 4

@# 12. Which is the cause of low attenuation in the basal ganglia?

A. Hypoparathyroidism

B. Pseudohypoparathyroidism

C. Hypothyroidism

D. Wilson’s disease

E. Radiation therapy

Answer 4

D. Wilson’s disease

Other causes increase CO poisoning, barbiturate intoxication, hypoxia, hypoglycaemia and lacunar infarcts.

Question 5

13. On review of an MRI of a complex case marked hypointensity of the globus pallidus is noted on T2W1, surrounding a higher intensity centre, ‘eye of the tiger sign’. Which is the most likely cause?

A. Dandy-Walker malformation

B. Multiple sclerosis

C. Hypoparathyroidism

D. Wilson’s disease

E. Hypoglycaemia

Answer 5

D. Wilson’s disease

Due to excess iron accumulation, a central gliosis is associated with Haltervorden-Spatz disease, dementia, retinitis pigmentosa, X-linked disorders with mental retardation, atrophy and Parkinsonian disorders.?

Question 6

20. Which of the following is not typical of Creutzfeldt-Jakob disease (CJD)?

A. Progressive dementia

B. Ataxia

C. Hyperintensity on T2 in head of caudate and putamen

D. Bilateral involvement

E. Gadolinium enhancement of lesion

Answer 6

E. Gadolinium enhancement of lesion

No gadolinium enhancement and no white matter involvement.

Question 7

29. Which is the most common imaging finding in neurosarcoidosis?

A. Leptomeningeal contrast enhancement

B. Hyperintense white matter T2 lesion

C. Grey matter lesions enhancing on MR

D. Involvement of the hypothalamus

E. Focal epidural masses

Answer 7

A. Leptomeningeal contrast enhancement

Basilar meninges often involved. B-E are recognised imaging findings. Spinal disease is less common than brain disease and findings include intramedullary lesions and intrathecal nodular masses.

Question 8

5) A 14-year-old boy with a recent history of viral upper respiratory tract infection presents with a 2-day history of rapid onset of fever and lethargy progressing to reduced consciousness and seizures. MRI shows several large lesions in the cerebral white matter, and a diagnosis of acute disseminated encephalomyelitis is made. Which additional finding is associated with most fulminant course of this disease, with a median survival of only 6 days?

a. grey matter involvement

b. high signal in the CSF on FLAIR images

c. generalized brain oedema

d. areas of petechial haemorrhage

e. enhancement with intravenous gadolinium

Answer 8

d. areas of petechial haemorrhage

Acute disseminated encephalomyelitis is an acute autoimmune demyelinating disease of the central nervous system that affects children more commonly than adults.

It is usually triggered by an inflammatory response to viral infections or vaccinations.

The main symptoms are decreased level of consciousness, varying from lethargy to coma, convulsions, and multifocal neurological symptoms.

MR imaging findings are of multifocal, large, confluent or punctate, high-signal, white matter lesions on T2W/FLAIR images.

Lesions are responsive to treatment with steroids and in 80% of cases completely resolve.

A haemorrhagic, hyperacute variant (acute haemorrhagic leukoencephalitis) has also been described and is known as Hurst’s disease.

In addition to the usual findings, there are multiple, white matter haemorrhages and rapid development of profound generalized mass effect. Hurst’s disease is usually fatal within a few days.

Question 9

12) A 14-year-old boy presents with a grossly abnormal gait, kyphoscoliosis and upper limb tremors. MRI shows mild atrophy of the cerebellum and much more marked cervicomedullary junction thinning with decreased anteroposterior diameter of the upper cervical spinal cord, which returns normal signal. What is diagnosis?

a. Friedreich’s ataxia

b. Creutzfeldt–Jakob disease

c. olivopontocerebellar atrophy

d. Huntington’s disease

e. tuberous sclerosis

Answer 9

a. Friedreich’s ataxia

Loss of myelinated fibres and gliosis in the posterior and lateral columns of the spinal cord are the histopathological hallmarks of Friedreich’s ataxia.

On MRI, the predominant radiological finding is thinning of the cervical spinal cord and medulla, and there may be associated mild cerebellar atrophy.

Conversely, in the majority of other forms of ataxia such as early onset cerebellar ataxia and olivopontocerebellar atrophy, atrophy of the cerebellum and pons predominates with relative sparing of the cord.

Although cerebellar atrophy may be seen in Friedreich’s ataxia, it is less pronounced than in these other diseases.

Question 10

15) A 32-year-old man of African descent presents to the neurologist with a several-month history of headache followed by rapid onset of bilateral facial weakness and blurring of vision. An MRI shows thickening of the basal leptomeninges, which enhance with intravenous gadolinium. Abnormal areas are identified in the pituitary gland, and optic and facial nerves, which all return low signal on T1W images and high signal on FLAIR images. What is the most likely diagnosis?

a. multiple sclerosis

b. tuberculous meningitis

c. neuroamyloidosis

d. neurosarcoidosis

e. lymphoma

Answer 10

d. neurosarcoidosis

Neurosarcoidosis is seen in up to 8% of cases of sarcoidosis and has a tendency to involve the base of the brain.

Cranial nerve involvement occurs frequently and nerve palsies are a common presenting feature.

Bilateral facial nerve palsies, particularly in young adults, are most commonly due to neurosarcoidosis.

The most common imaging manifestation is diffuse basomeningeal thickening, which typically shows enhancement with intravenous gadolinium. Also frequently seen are meningeal nodules and deep white matter lesions with high T2 signal.

Multiple or solitary parenchymal masses may also occur, which can have a ring-like appearance and may therefore mimic primary or metastatic neoplasia.

Question 11

21) A 52-year-old female presents with increasing short-term memory problems. CT and MR scans are normal. A perfusion scintigraphy study of the brain shows reduced perfusion in the posterior parietal regions bilaterally. What is the most likely diagnosis?

a. Alzheimer’s disease

b. vascular dementia

c. Lewy body dementia

d. frontotemporal dementia

e. Parkinson’s disease

Answer 11

a. Alzheimer’s disease

Alzheimer’s disease typically presents with atrophy and reduced perfusion to the mesiotemporal regions bilaterally, but, in younger patients, it often presents with posterior parietal perfusion abnormalities.

Vascular dementia shows patchy cortical and subcortical perfusion defects, with involvement of the cerebellum.

Lewy body dementia is similar to Alzheimer’s disease but with less occipital sparing;

Parkinson’s dementia is also similar but with less mesiotemporal change and more involvement of the visual cortex.

Question 12

23) A 22-year-old man presents with a 6-week history of progressive worsening confusion. Initial CT examination is normal. Following neurological review, the patient undergoes MRI, at which the only abnormality seen is high signal in the posterior portions of the thalami bilaterally on T2W and FLAIR images. What is the most likely condition?

a. acute disseminated encephalomyelitis

b. variant Creutzfeldt–Jakob disease

c. multiple sclerosis

d. metachromatic leukodystrophy

e. Rasmussen’s encephalitis

Answer 12

b. variant Creutzfeldt–Jakob disease

Variant Creutzfeldt–Jakob disease is a rare but important, transmissible, rapidly progressive spongiform encephalopathy and a cause of dementia and death in young patients.

The transmissible agent is thought to be a prion protein (proteins devoid of nucleic acid), and the condition is causally linked to bovine spongiform encephalopathy.

CT is typically normal, but symmetrical hyperintensity in the pulvinar nuclei of the posterior thalami (pulvinar sign) on T2Wor FLAIR MR images has been described as a specific sign for the variant form.

The classic form affects an older age group and is often genetically linked, whereas the variant form is sporadic.

The pulvinar sign is seen only in the variant form, with the classic type typically showing similar hyperintense abnormalities located in the caudate nucleus and putamen.

Question 13

28) With ageing, iron accumulates in tissues of the brain and is seen as low signal on both T1W and T2W sequences at MRI. Which of the following locations for iron deposition is pathological in a 60-yearold man and may indicate onset of dementia?

a. putamen

b. globus pallidus

c. red nucleus

d. dentate nucleus

e. pars reticulate

Answer 13

a. putamen

Non-haem brain iron is normally found within oligodendroglia and astrocytes, with smaller amounts in neurons and myelinated axons.

Half is found within the mitochondria and 10% in the nuclei, and 40% represents a soluble fraction.

The areas of maximum iron concentration in normal adults are found in the globus pallidus, red nucleus, pars reticulata of the substantia nigra and dentate nucleus of the cerebellum.

The brain concentration is independent of general body stores, and the mechanism by which it crosses the blood–brain barrier is not fully understood.

By the eighth decade, the concentration of iron may increase in the caudate nucleus and putamen to levels similar to those seen in the globus pallidus.

Excessive or premature accumulation in these areas has been seen in various forms of senile dementia including Alzheimer’s disease.

Iron deposition is identified on T1W and T2W sequences as signal hypointensity due to magnetic susceptibility.

Question 14

38) Which of the followingMR sequences ismost sensitive for detecting subcortical and periventricular lesions in multiple sclerosis?

a. axial T1W

b. axial T2W

c. axial FLAIR

d. axial proton density

e. axial T1W post-gadolinium contrast

Answer 14

c. axial FLAIR

The FLAIR MR sequence is a heavily T2-weighted inversion recovery sequence designed to nullify the signal from CSF. This highlights any T2 high-signal lesions that may be masked on standard T2W images by adjacent high signal of CSF. This is of particular benefit in the periventricular region and corpus callosum, and studies have shown that FLAIR has higher accuracy than intermediate and T2W sequences in the detection of supratentorial cortical, subcortical and periventricular multiple sclerosis lesions. Depending on location, some lesions can be best seen on standard T2W images; these areas include the posterior fossa, BS and spinal cord.

Question 15

42) An elderly man undergoes CT for gradual onset of confusion and memory loss. A pattern of generalized global brain atrophy showing marked temporal lobe predominance with an increase in size of the hippocampal–choroidal fissure is seen. Coronal T2W images show atrophy of the hippocampus bilaterally. Which condition is most likely to result in such a pattern of volume loss?

a. Pick’s disease

b. Alzheimer’s disease

c. Parkinson’s disease

d. Lewy body dementia

e. multi-infarct dementia

Answer 15

b. Alzheimer’s disease

Alzheimer’s disease is a progressive neurodegenerative disorder and the most common cause of dementia in elderly people. Current thinking is that imaging can help in the early diagnosis by documenting or quantifying atrophy in certain regions of the brain such as the hippocampus and entorhinal cortex. However, conventional structural imaging has a relatively low sensitivity in Alzheimer’s disease and may be normal. Therefore, use is limited to identification of patterns of atrophy and the exclusion of other potential causes of dementia such as normal pressure hydrocephalus, vascular dementia or space-occupying lesion. Patterns of atrophy, when seen, may be relatively specific for different causes of dementia, with hippocampal atrophy a cardinal radiological sign of Alzheimer’s disease.

Pick’s disease has a frontal and temporal preponderance and is part of the rarer group of diseases under the umbrella term ‘frontotemporal lobar degeneration’.

Lewy body dementia typically affects the parietal and occipital lobes and the cerebellum, which are usually spared in Alzheimer’s disease.

Multiinfarct dementia is vascular in origin and will show a patchy distribution of change. The different patterns of atrophy have also been recently demonstrated with 18FDG PET.

Question 16

(Ped) 43) A 10-year-old girl being treated for acute lymphoblastic leukaemia presents with a sudden onset of weakness. The leukocyte count is well below 100 000/mm3, and the platelet count is well below 10 000/mm3. Unenhanced CT brain is normal. Which of the following imaging techniques is most likely to demonstrate the cause of the signs?

a. post-contrast CT brain

b. CT venogram

c. MR venogram

d. DWI

e. gradient echo MRI

Answer 16

e. gradient echo MRI

In children with cancer, acute neurological symptoms may be caused directly by the cancer or by its treatment.

Paediatric tumours commonly metastasizing to the brain include neuroblastoma, osteosarcoma and Ewing’s sarcoma.

Rarer causes are melanoma, Wilms’ tumour and rhabdomyosarcoma. Of these, the sarcomas are most commonly associated with intratumoral bleeding.

Spontaneous bleeding is seen in thrombocytopenia (platelets ,10 000/mm3) and disseminated intravascular coagulation.

Large areas of haemorrhage will be evident on CT, but petechial haemorrhage is best seen on gradient echo MR.

Ischaemia or infarction can be caused by non-bacterial thrombotic endocarditis, disseminated intravascular coagulation, septic infarction, tumour embolism, venous occlusion and radiation-induced vasculopathy.

Radiation-induced vasculopathy can be acute (1–6 weeks) or early delayed (3 weeks to several months), and both are caused by oedema and transient myelin injury. All radiation injury is confined to the field of treatment. Late delayed reaction (several months to years) is accelerated atherosclerosis and white matter infarction consequent on this. Extensive demyelination, white matter necrosis and subsequent astrogliosis can also occur. With ischaemic damage, hyperintense signal may be seen on DWI as early as 1 hour.

Hyperleukocytosis (leukocyte count >100 000/mm3) causes vascular thrombosis, into which there can be secondary haemorrhage. CTor MR venography can be used to look for venous occlusion, particularly venous sinus thrombosis.

Question 17

76) Bilateral globus pallidus injury manifest radiologically as high signal on T2W MR sequences is indicative of poisoning by which of the following substances?

a. lead

b. methanol

c. carbon monoxide

d. carbon dioxide

e. mercury

Answer 17

c. carbon monoxide

Carbon monoxide poisoning results in irreversible formation of carboxyhaemoglobin in the blood, causing anoxic ischaemic encephalopathy. These changes are usually bilateral and affect the basal ganglia, most commonly the globus pallidus. Injury is demonstrated as high signal on T2W and FLAIR images, and shows restricted diffusion on DWI. Areas less commonly affected acutely are the putamen (which is characteristically involved in methanol poisoning) and caudate nucleus. Involvement elsewhere can occur but is less common than basal ganglia changes.

Delayed post-anoxic encephalopathy may develop several weeks after carbon monoxide poisoning, and MRI then shows further high T2 signal changes in the corpus callosum, subcortical U fibres, and internal and external capsules, with low T2 signal changes in the thalamus and putamen.

Question 18

81) A 31-year-old woman presents to the neurologist with a transient episode of facial numbness. On close questioning, she reveals a transient episode of blurred vision which occurred several months previously. MRI, including MR angiography, shows several small areas of low signal on T1W and high signal on T2W images in the optic nerves and cerebellar peduncles. The FLAIR sequence demonstrates further multiple, ovoid, high-signal areas in the corpus callosum and periventricular white matter. The angiogram demonstrates normal head and neck vessels. These imaging findings support which of the following diagnoses?

a. internal carotid artery dissection

b. multiple sclerosis

c. progressive multifocal leukoencephalopathy

d. acute disseminated encephalomyelitis

e. wallerian degeneration

Answer 18

b. multiple sclerosis

MRI is an important paraclinical tool to support the clinical diagnosis of multiple sclerosis.

Multiple sclerosis is an inflammatory autoimmune disease of the brain and spine characterized by demyelination and damage to axons.

It typically presents in a relapsing and remitting way with symptoms dependent on the location of lesions.

MR enables identification of areas of tissue injury and disease progression, and location of active lesions.

The lesions are high signal on T2W sequences (including FLAIR) and can be found throughout the brain, but have a predilection for periventricular white matter, appearing perpendicular to the ventricles with an ovoid conformation (Dawson’s fingers).

The corpus callosum and cranial nerves are also common sites, and the FLAIR sequence helps to reveal lesions that would otherwise be masked by the high T2 signal of CSF. The corpus callosum is best examined on sagittal sequences. On T1W sequences, lesions are often isointense, but low signal can indicate areas of severe inflammation (so-called black holes) resulting in disease progression and disability.

Enhancement with intravenous gadolinium is sometimes seen in lesions during the acute inflammatory phase and is thought to be the earliest detectable sign on MRI

Question 19

11 A patient presents with bradykinesia, rigidity and tremor. 1231- ioflupane is administered and the images, acquired 4 hours post injection, reveal significant depletion of uptake in the corpus striatum. Which of the following could not account for these appearances?

(a) Parkinson’s disease whilst on levodopa treatment

(b) Lewy body dementia

(c) Progressive supranuclear palsy

(d) Shy-Drager syndrome

(e) Fronto-temporal dementia

Answer 19

(e) Fronto-temporal dementia

Parkinson’s disease, Lewy-body dementia and ‘Parkinson’s plus’ syndromes (e.g. progressive supranuclear palsy, corticobasal degeneration and multiple system atrophy) all cause a significant reduction of uptake of 1231-ioflupane in the corpus striatum.

Question 20

17 A demented, 60 year old gentleman with a gait apraxia and urinary incontinence is noted to have hydrocephalus on a CT Head. No obstructive lesion is found, and a trial of CSF withdrawal provides some clinical improvement. Given the most likely diagnosis, which of the following would be an unexpected finding?

(a) Periventricular high signal on FLAIR imaging

(b) Radiotracer accumulation in the lateral ventricles after instillation of 111 ln-DTPA via a lumbar puncture

(c) Downward bowing of the corpus callosum

(d) Normal opening pressure at lumbar puncture

(e) A prominent aqueductal flow void on MR imaging

Answer 20

(c) Downward bowing of the corpus callosum

This patient is suffering from normal pressure hydrocephalus, a potentially treatable cause of dementia in the elderly. Appearances are of communicating hydrocephalus, with ventricles dilated out of proportion to sulcal effacement, upward bowing of the corpus callosum, a pronounced aquaductal flow void on MRI, periventricular hyperintensity, and reflux of indium 111 ln-DTPA into the lateral ventricles.

Question 21

27 A young woman with a family history of a movement disorder presents with rigidity and bradykinesia. MR imaging reveals prominent, localised areas of central high T2W signal within both globus pallidi - although this appears to be on a background of generally decreased signal within these nuclei. Decreased Ti2W signal is also found in the red nuclei and substantia riigra. What diagnosis is suggested by these appearances?

(a) Hallervoden-Spatz syndrome

(b) Huntington chorea

(c) Wilson’s disease

(d) Cerebrotendinous xanthomatosis

(e) Rett syndrome

Answer 21

(a) Hallervoden-Spatz syndrome

The basal ganglia/has the ‘eye of the tiger’ appearance. In combination with the hereditary movement disorder, this suggests Hallervodern-Spatz disease. Other causes of this sign include: CO poisoning, corticobasal ganglionic degeneration, Leigh syndrome, neurofibromatosis, progressive supranuclear palsy, Shy-Drager syndrome, toxins.

Question 22

15 A patient presents with multiple relapsing focal neurological deficits. Which MR imaging feature would be unusual in multiple sclerosis?

(a) Cortical central atrophy

(b) Atrophy of the corpus callosum

(c) Hypointense thalamus on T2W

(d) Hypointense plaques on T2W

(e) Spinal cord involvement

Answer 22

(d) Hypointense plaques on T2W

MS plaques are typically of high-signal intensity on T2W and Proton density imaging. The hypointense thalamus (and putamen) are due to increased ferritin.

Question 23

23 A man referred from the memory clinic has a 99mrc-HMPAO cerebral SPECT. Temporo-parietal hypoperfusion is found. What is the most likely diagnosis?

(a) Pick’s disease

(b) Chronic alcoholism

(c) Aids-related dementia

(d) Lewy-body disease

(e) Multi-infarct dementia

Answer 23

(d) Lewy-body disease

Temporo-parietal hypoperfusion is typically caused by Alzheimer’s type dementia or Lewy body disease.

Two other patterns to consider include:

firstly fronto-temporal hypoperfusion, caused by Pick’s disease, fronto-temporal dementia, chronic alcoholism and schizophrenia;

and secondly patchy/ multiple perfusion defects, caused by AIDS-related dementia, schizophrenia and multi-infarct dementia.

Question 24

(Ped) 26 A 14 year old boy presents with a head injury following an RTA. A junior SpR reviews the unenhanced-CT head examination and is happy there is no sign of trauma, however, they are concerned by an area of calcification. At which of the following sites would calcification be considered abnormal, requiring further investigation?

(a) Basal ganglia

(b) Choroid plexus

(c) Dura

(d) Pineal gland

(e) Pituitary gland

Answer 24

(e) Pituitary gland

Pathological calcification is present in 1.6% of children; examples include pituitary fossa, mamillary bodies, habenular commissure, corpus callosum and tectal plate.

Calcification within the intrasellar or parasellar region raises the possibility of a craniopharyngioma.

All ‘normal’ sites of intracranial calcification increase in frequency with age, and include pineal (< 1 cm), choroid plexus, dural (may also be due to haemorrhage).

There are numerous causes of basal ganglia calcification, but idiopathic is seen as a normal variant.

Question 25

34 A 55 year old patient presents with head trauma. A CT head is performed and bilateral calcification of his basal ganglia is noted. Which of the following is not a recognised cause?

(a) Sturge-Weber-Dimitri syndrome

(b) Fahr’s disease

(c) Hypoparathyroidism

(d) Pseudo-pseudohypoparathyroidism

(e) Hypoxia

Answer 25

(a) Sturge-Weber-Dimitri syndrome

Sturge-Weber syndrome is associated with calcification of the cortical gyri, rather than the basal ganglia.

The cause of basal ganglia calcification can be divided into: physiologic, endocrine, (e.g. hypothyroidism, hypoparathyroidism, pseudo- and pseudopseudohypoparathyroidism), metabolic (e.g. Fahr’s disease and mitochondrial cytopathies), congenital/ developmental (e.g. Cockayne’s syndrome), infection (e.g. TORCH, cystercercosis, tuberculosis), toxic (e.g. CO poisoning, hypoxia, lead), and chemotherapy/ radiotherapy.

Question 26

52 After review of a CT head examination, i.v. contrast medium is administered. The enhancement follows the gyral/ sulcal pattern and involves the meninges around the basal cisterns. Which of the following conditions can give rise to this enhancement pattern?

(a) CSF leak

(b) Pachymeningitis

(c) Spontaneous intracranial hypotension

(d) An intraventricular shunt

(e) Sarcoid

Answer 26

(e) Sarcoid

This is a leptomeningeal pattern of enhancement. This can be seen in acute stroke, leptomeningeal meningitis, inflammatory disea~es such as sarcoid, and metastasis.

Question 27

57 A patient with chronic alcoholic liver disease is admitted with confusion. MR imaging of the brain is performed. Which of the following imaging features is not associated with alcohol intake?

(a) Enlargement of the mammillary bodies

(b) Periventricular demyelination

(c) Hyperintense focii within the corpus callosum on T2W

(d) Atrophy of the corpus callosum

(e) Hyperintense lesions within the pons on T2W

Answer 27

(a) Enlargement of the mammillary bodies

Wernicke’s encephalopathy is associated with necrosis of the mammillary bodies and periventricular demyelination.

MarchifavaBignami disease is associated with hyperintense foci within the corpus callosum on T2W; pontine myelinosis is associated with hyperintense lesions within the pons. Atrophy of the corpus callosum is a recognized feature.

Question 28

15. A 14 year old boy presents with a progressive history of gait and speech disturbance. On both T1- and T2-weighted MR imaging, the globus pallidi are markedly hypointense except for a small central region of high signal intensity. The findings are more pronounced on T2-weighted imaging. What is the most likely diagnosis?

a. Leigh’s disease

b. Hallervorden–Spatz syndrome

c. Wilson disease

d. Mytochondrial encephalomyelopathy

e. Parkinson’s disease

Answer 28

15.b. Hallervorden–Spatz (HS) syndrome

The finding described on MRI is the ‘eye-of-the-tiger’ sign. This is closely associated with HS. HS is a progressive neurodegenerative metabolic disorder characterised by extrapyr- amidal and pyramidal signs.

The condition (for which the pathophysiology is unclear) results in the accumulation of iron within the globus pallidi and brainstem nuclei.

Two clinical entities exist: familial and sporadic.

The familial (classic) form shows earlier onset and rapid progression.

The sporadic (atypical) form is characterised by a later onset, often in teenage years, with slower progression.

Although the ‘eye-of-the-tiger’ sign is closely associated with HS, it has been demon- strated in other rare extrapyramidal parkinsonian disorders including cortical-basal ganglionic degeneration, early-onset levodopa unresponsive parkinsonism and progressive supranuclear palsy.

Question 29

24. Which is the preferred sequence to use when attempting to identify posterior fossa lesions on MRI in patients with multiple sclerosis?

a. T1-weighted spin-echo

b. T2-weighted spin-echo

c. FLAIR

d. Gradient-echo

e. Proton density

Answer 29

24. b. T2-weighted spin-echo

Multiple sclerotic plaques can be located anywhere in the central nervous system but typically they form at the junction of the cortex and white matter and periventricularly. FLAIR is particularly good at locating periventricular lesions as CSF signal is suppressed. In the posterior fossa, however, FLAIR detects fewer lesions than T2-weighted spin-echo.

Question 30

27. A three year old girl undergoes a CT scan of her head following trauma. No acute pathology is demonstrated but there is basal ganglia calcification. Which of the following can be excluded as a cause of the calcification?

a. Down’s syndrome

b. Neurofibromatosis

c. Birth hypoxia

d. Wilson disease

e. Congenital rubella

Answer 30

27. d. Wilson disease

Causes of basal ganglia calcification include:
* Physiological aging.
* Infections/inflammatory: TORCH, TB, cysticercosis, measles, chickenpox, pertussis, Coxsackie B virus, AIDS, SLE.
* Toxins: lead, carbon monoxide, birth anoxia/hypoxia, chemotherapy/radiotherapy, nephrotic syndrome.
* Congenital: Cockayne’s, Fahr’s and Down’s syndromes, neurofibromatosis, tuberous sclerosis, methaemaglobinopathy.
* Endocrine: hypoth, hypopth, pseudhypopt, pseudopseudohypopth, hyperpth
* Metabolic: Leigh disease, mitochondrial cytopathies.
* Trauma: infarction.

Question 31

45. A homeless adult male is admitted with a change in mental state and a metabolic abnormality. CT shows a focus of reduced attenuation in the pons. On MRI the focus is hypointense on T1 and hyperintense on T2. There is restricted diffusion on diffuse ion weighted imaging and there is no enhancement post-contrast. What is the most likely diagnosis?

a. Brainstem glioma

b. Metastasis

c. Infarction

d. Tuberculosis

e. Osmotic myelinolysis

Answer 31

45. e. Osmotic myelinolysis

Osmotic myelinolysis is also referred to as central pontine myelinolysis or osmotic demyelination syndrome.

It is classically seen in an alcoholic, hyponatraemic patient in which rapid correction of sodium releases myelinotoxic compounds leading to destruction of myelin sheaths.

The pons is the commonest site, although extra-pontine areas such as basal ganglia, cerebellar white matter and thalami may also be involved.

Some patients completely recover but the six-month survival rate is only 5–10%.

Brainstem gliomas tend to occur in children and young adults.

Typically the brainstem is asymmetrically expanded with displacement/compression of adjacent cisterns. Local vessels may also be displaced. Enhancement is variable.

Pontine/medulla infarcts account for approximately 2% of all brain infarcts. They may show similar appearances to those described in the question but may also demonstrate enhancement.

One would expect enhancement with metastasis.

Question 32

55. A 35 year old female presents with worsening headache and facial droop. Her chest radiograph is abnormal. Non-contrast-enhanced CT brain is unremarkable. MRI demonstrates leptomeningeal thickening and enhancement, particularly around the basal cisterns. Enhancement extends along the right seventh cranial nerve and along the optic nerves. There are several small superficial parenchymal enhancing lesions found bordering the basal cisterns. What is the most likely diagnosis?

a. Sarcoidosis

b. Tuberculosis meningitis

c. Carcinomatous meningitis

d. Lymphoma

e. Behcet syndrome

Answer 32

55. a. Sarcoidosis

Neurologic manifestations of sarcoidosis occur in 5% of patients. In over 80% of established cases, the chest radiograph is abnormal. Sarcoidosis can involve any part of the nervous system, however it has a predilection for the leptomeninges (arachnoid and pia mater).

The most common sites for the disease are the basal meninges and the basal midline structures including the hypothalamus, optic chiasm and pituitary.

Sarcoidosis also commonly involves the cranial nerves, which may reveal abnormal enhancement on contrast-enhanced T1-weighted imaging. The facial nerve is the most common cranial nerve involved clinically, whereas radiologically, the optic nerves are most commonly abnormal.

Dural thickening/dural-based masses may also be present.

Parenchymal sarcoidosis can be seen as enhancing granulomas usually located superficially in the brain parenchyma bordering the basal cisterns.

Non-enhancing lesions in the periventricular white matter and brainstem are common.

Hydrocephalus occurs in approximately 10% of cases.

Question 33

58. A 40 year old unkempt male is admitted with disorientation and ataxia. FLAIR, T2 and diffusion-weighted MR imaging reveal abnormal high signal in both medial thalami, the hypothalamus and peri-aqueductal gray matter. There is atrophy of the right mamillary body. What is the most likely diagnosis?

a. Lymphoma

b. Viral encephalitis

c. Creutzfeldt–Jacob disease

d. Wernicke’s encephalopathy

e. Venous thrombosis

Answer 33

58. d. Wernicke’s encephalopathy (WE)

WE refers to an acute or subacute syndrome characterised by disorientation, gaze paralysis, ataxia and nystagmus.

It invariably occurs in chronic alcoholics but it is caused by thiamine deficiency.

Involvement of the medial thalami is characteristic and typically the mammillary bodies, peri-aqueductal grey matter and hypothalamus are also involved.

In the acute stages of the disease, haemorrhage, necrosis and oedema are encountered, whereas in the latter stages these regions tend to atrophy, particularly the mamillary bodies.

Question 34

QUESTION 15
A 33-year-old woman presents to the Emergency Department with a reduced conscious level. She has been generally unwell with fever, malaise and a dry cough for several weeks and more recently has developed a left facial nerve palsy. An MRI brain reveals nodular thickening and enhancement of the dura and leptomeninges. There is also enhancement of the optic tracts and optic chiasm, as well as the pituitary infundibulum. A few small foci of high T2 signal are demonstrated in the periventricular white matter. What is the most likely diagnosis?

A Multiple sclerosis

B Langerhans cell histiocytosis

C Progressive multifocal leucoencephalopathy

D Sarcoidosis

E Wilson’s disease

Answer 34

D Sarcoidosis

Enhancement involving the optic apparatus, floor of the third ventricle and pituitary infundibulum is particularly suggestive of sarcoidosis.

Question 35

QUESTION 21
A 76-year-old man who has been previously well attends for a CT head as part of investigations for dementia. This reveals severe atrophy of the anterior temporal lobes, more marked on the right side. Which one of the following conditions is this most suggestive of?

A Alzheimer’s disease

B Encephalitis

C Lewy body dementia

D Multisystem atrophy

E Pick’s disease

Answer 35

E Pick’s disease

Asymmetrical temporal (and sometimes frontal) lobe atrophy is typical of Pick’s disease.

Question 36

(Ped) QUESTION 23
Following a recent viral illness, a 5-year-old girl presents with a fluctuating conscious level, seizures and left leg weakness. She is apyrexial and does not have a rash. An MRI is performed. This shows bilateral areas of increased T2 signal in the subcortical white matter and cerebellum and deep grey matter. Which one of the following is the most likely diagnosis?

A Acute disseminated encephalomyelitis (ADEM)

B Bacterial meningitis

C Multiple sclerosis

D Venous sinus thrombosis

E Viral encephalitis

Answer 36

A Acute disseminated encephalomyelitis (ADEM)

ADEM can occur following a viral illness and is classically a monophasic illness that occurs in multiple sites within the brain and the spinal cord. Multiple sclerosis is a possible diagnosis; however, the clinical history makes this far less likely.

Question 37

A 56-year-old man who is known to drink excessive amounts of alcohol is admitted to the Emergency Department with a GCS of 10. His routine blood tests reveal profound hyponatraemia. He is treated and his serum sodium level is normal 2 days later. However, his GCS has dropped to 6. What are the most likely findings on MRI?

A Foci of high T2 signal at the corticomedullary junction

B Foci of high T2 signal in both cerebellar hemispheres and occipital lobes

C Herniation of the cerebellar tonsils through the foramen magnum

D High T2 signal in the pons, basal ganglia and thalami

E Loss of grey-white matter differentiation

Answer 37

D High T2 signal in the pons, basal ganglia and thalami

This is osmotic myelinolysis (also known as central pontine myelinolysis).

Question 38

QUESTION 77
A 45-year-old woman presents with a history of tingling in her right leg, painful eye movements and fatigue. Her symptoms tend to last for a few days/ weeks and then resolve for some time before returning. Which of the following is the most likely finding on MRI?

A Dural thickening and multiple small meningeal masses

B High signal on T2w images in the periventricular white matter especially around the frontal horns of the lateral ventricles and in the basal ganglia

C Multiple large irregular lesions of high T2 signal in the subcortical white matter, brainstem and cerebellum

D Ovoid lesions of high T2 signal in the periventricular white matter orientated parallel to the lateral ventricles

E Ovoid lesions of high T2 signal in the periventricular white matter orientated perpendicular to the lateral ventricles

Answer 38

E Ovoid lesions of high T2 signal in the periventricular white matter orientated perpendicular to the lateral ventricles

This is a common presentation of multiple sclerosis, which typically has a relapsing-rcmitting course. plaques of demyelinadon are characteristically orientated perpendicular to the lateral ventricles and parallel to the spinal cord

Question 39

2. A patient presents with recent onset neurological symptoms suspicious of an acute presentation of MS. Which of following anatomical sites of plaque involvement is least consistent with this?

A. Corpus callosum.

B. Spine involvement in the absence of brain involvement.

C. Cerebral cortex.

D. Symmetrical involvement of cerebral white matter.

E. Floor of the fourth ventricle.

Answer 39

2. D. Symmetrical involvement of cerebral white matter.

Symmetrical involvement of the cerebral hemispheres or cerebellar peduncles is unusual in MS and is occasionally seen in acute disseminated encephalomyelitis (ADEM).

ADEM can mimic an acute presentation of MS both clinically and in terms of imaging findings.

The monophasic nature of ADEM can be deduced both from the uniformity of lesional oedema and contrast enhancement in the acute phase.

Lesions in ADEM resolve on follow-up, and although enhancing and non-enhancing lesions can coexist for a period, new lesions should not appear.

MS plaques are classically seen in the periventricular and juxtacortical white matter.

The other options in the question are all common plaque locations.

Involvement of the corpus callosum is characteristic.

Other common supratentorial sites include the white matter abutting the temporal horns and trigones of the lateral ventricles. Cortical lesions are less conspicuous on MRI than white matter lesions, but their detection is improved by the inclusion of a FLAIR sequence.

Juxtacortical white matter lesions are highly suggestive of MS, as lesions are not commonly seen in this region in normal ageing.

Twelve per cent of patients have lesions on MRI limited to the spine without brain involvement.

Question 40

@# 31. A 58-year-old patient is found at home with a reduced GCS. CT brain reveals atrophy only. MRI brain reveals hyperintensity in the tegmentum (except for the red nucleus) and hypointensity of the superior colliculus on T2WI, as well as hyperintensity in the basal ganglia. What is the most likely cause?

A. Cocaine abuse.

B. Methanol poisoning.

C. Primary basal ganglia haemorrhage.

D. Wilson’s disease.

E. Carbon monoxide poisoning.

Answer 40

31. D. Wilson’s disease.

Hyperintensity in the tegmentum (except for the red nucleus) and hypointensity of the superior colliculus are described as the ‘face of the giant panda sign’ and are seen in axial T2WI sections of the midbrain in Wilson’s disease.

A ‘double panda sign’ has also been described, with a second ‘panda cub face’ in the pons.

Abnormal signal can also be seen in the basal ganglia and thalamus in Wilson’s disease (putamen most commonly).

The signal abnormalities are due to copper deposition. Signal is generally reduced on T1WI sequences, although it may be increased due to the paramagnetic effects of copper and also due to the hepatic component of Wilson’s disease (a portocaval shunt can produce this latter finding). Signal is generally increased on T2WI sequences, but it can be of mixed or reduced intensity.

Similarly carbon monoxide poisoning and methanol poisoning can cause increased or reduced signal on T1WI.

Methanol poisoning typically causes abnormal signal in the putamen, with haemorrhagic necrosis being more typical, whereas carbon monoxide poisoning typically affects the globus pallidus. The latter would be expected to cause low attenuation in the basal ganglia on CT.

The findings on CT exclude basal ganglia haemorrhage.

Amphetamine and cocaine abuse can cause high T2WI signal in the basal ganglia due to small areas of infarction, but are not associated with the midbrain changes.

Question 41

33. A 65-year-old woman with a history of previous subarachnoid haemorrhage presents with slowly progressive cognitive decline and worsening gait. A CT brain reveals ventricular dilatation with rounded frontal horns and periventricular hypodensity. What is the most likely diagnosis?

A. Heavy metal toxicity secondary to aneurysm clip.

B. Parkinson’s disease.

C. Alzheimer’s disease.

D. Normal pressure hydrocephalus.

E. Binswanger’s disease.

Answer 41

33. D. Normal pressure hydrocephalus.

Fifty per cent of cases of normal pressure hydrocephalus (NPH) are idiopathic, while 50% have a cause, e.g. meningitis, neurosurgery, head trauma, or, as in the current vignette, previous subarachnoid haemorrhage. The imaging reveals dilated ventricles with rounded frontal horns, which are enlarged out of proportion to the degree of sulcal enlargement (as one would see in cerebral atrophy). On CT there may be periventricular low attenuation in the frontal and occipital regions, representing transependymal CSF flow. The MRI equivalent is periventricular high signal and there are other MRI findings, including upward bowing of the corpus callosum and the aqueductal flow void sign (reflecting increased CSF velocity through the cerebral aqueduct). The bradykinesia and gait apraxia of NPH may mimic Parkinson’s disease, although there is typically no associated tremor.

Binswanger’s disease (also known as subcortical arteriosclerotic encephalopathy) is a continuous, irreversible ischaemic degeneration of periventricular and deep white matter. MRI reveals extensive periventricular and deep white matter hyperintensities, reflect microinfarctions and demyelination, and enlarged ventricles.

Question 42

@# 34. A 34-year-old liver transplant recipient presents to hospital with confusion and seizures. A CT brain reveals low attenuation in the deep and subcortical white matter of the occipital and parietal lobes bilaterally. There is no abnormal enhancement post IV contrast administration. As the reporting radiologist, you advise that the clinical team first:

A. measure blood glucose

B. measure serum alpha-feta protein

C. measure blood pressure

D. send coagulation screen

E. measure d-dimer.

Answer 42

34. C. Measure blood pressure

The CT findings are consistent with PRES. This is a usually reversible neurological syndrome with a variety of presenting symptoms ranging from altered mental status to seizures, headache, and loss of vision. Common causes include hypertension, eclampsia and preeclampsia, immunosuppressive medications such as cyclosporine, various antineoplastic agents (including interferon), SLE, and various causes of renal failure. Hypertension is common in PRES, but may be mild and is not universally present, especially in the setting of immunosuppression. However, in the vignette given, hypertension is a possible cause and should be sought. Cyclosporin or tacrolimus might be causes; the former is thought to result in PRES both via a direct neurotoxic effect and by causing hypertension. The condition is not always reversible and may result in haemorrhagic infarcts. The classic MRI finding is of hyperintensity on FLAIR in the parieto-occipital and posterior frontal cortical and subcortical white matter. Less commonly the brainstem, basal ganglia, and cerebellum are involved. Atypical imaging appearances include contrast enhancement, haemorrhage, and restricted diffusion on MRI. Abnormalities can often be seen on CT, as described in the vignette.

Question 43

@# 35. A 34-year-old female presents with neurological symptoms suggestive of MS and is referred for an MRI of brain by the neurology team. Which of the following sequences is most useful for determining if there are plaques of differing ages (i.e. dissemination in time)?

A. FLAIR.

B. T2WI.

C. Pre- and post-contrast T1WI.

D. Proton density.

E. STIR.

Answer 43

35. C. Pre- and post-contrast T1WI.

MS plaques are generally most conspicuous on FLAIR sequences.

However, if there are enhancing and non-enhancing plaques on T1WI post-contrast, this indicates plaques of differing ages, i.e. dissemination in time. While this is not diagnostic of MS (imaging alone never is), it is very suggestive.

Proton density sequences are useful, but not quite as useful as FLAIR sequences, in showing periventricular lesions.

T2WI sequences are superior to FLAIR sequences when it comes to detection of lesions in the posterior fossa and spinal cord.

T2W STIR is probably superior to standard T2WI sequences in detecting spinal cord lesions, but is not routinely used.

STIR sequences or fat suppression are useful when imaging the optic nerves, as contrast between lesions and the surrounding orbital fat is increased.

Question 44

@# 37. A 73-year-old has been referred for assessment of cognitive decline. A CT brain reveals cerebral atrophy and a dementia specialist refers her for PET-CT brain. Which of the following findings is most consistent with early Alzheimer’s disease?

A. Diffuse reduced activity.

B. Reduced activity in the precuneus and posterior cingulate gyrus.

C. Reduced activity in the frontotemporal regions.

D. Reduced activity in the caudate and lentiform nuclei.

E. Reduced activity bilaterally in the occipital cortex.

Answer 44

37. B. Reduced activity in the precuneus and posterior cingulate gyrus.

FDG-PET-CT has been shown to have a sensitivity and specificity of 93% for mild to moderate Alzheimer’s disease. The technique has been shown to provide important prognostic information so that a negative PET-CT scan is indicative of unlikely progression of cognitive impairment for a mean follow-up of 3 years in those patients who initially present with cognitive symptoms of dementia.

The more specific findings on PET-CT in Alzheimer’s disease are early reduced activity in the precuneus/posterior cingulate gyrus and the superior, middle, and inferior temporal lobe gyrus, with relative sparing of the primary sensorimotor and visual cortex, and sparing of the striatum, thalamus, and cerebellum.

Diffuse reduced activity of the cortical/subcortical regions and cerebellum is more typical of multiinfarct dementia.

Reduced activity in the fronto-temporal regions is more consistent with fronto-temporal dementia.

Reduced activity in the occipital cortex reflects the visual problems encountered in lewy body dementia.

Reduced activity in the caudate and lentiform nuclei is more typical of Huntingdon’s chorea.

Question 45

57. A 62-year-old man presents with tremor and incontinence. Examination reveals bradykinesia and gait ataxia. He is also noted to have a reduced mini mental state examination (MMSE) and postural hypotension. He has an MRI scan of brain as part of the diagnostic workup. On the axial T2WI a cruciform hyperintensity in the pons is noted. Which of the following is the most likely diagnosis?

A. Parkinson’s disease.

B. Multisystem atrophy (MSA).

C. Progressive supranuclear palsy (PSP).

D. Cryptobasal degeneration.

E. Lewy body dementia.

Answer 45

57. B. Multisystem atrophy (MSA).

T2WI cruciform hyperintensity or the ‘hot cross bun’ sign within the pons, is suggestive of MSA, although it is not specific, as it also occurs in spinocerebellar ataxia. Other MRI features include hyperintensity within the putamen. Patients with MSA typically have parkinsonian features poorly responsive to levodopa therapy and autonomic disturbance. MRI features of Parkinson’s disease are generally non-specific, but narrowing of the pars compacta of the substantia nigra may be seen on T2WI. Substantia nigra atrophy is also a feature of Lewy body dementia. T2WI hypointensity of the putamen due to iron deposition is a feature of progressive supranuclear palsy.

Question 46

36. A 34-year-old woman presents with a seizure. She has a history of migraine and low mood over the preceding year, and reported occasional episodes of confusion. On examination there is slight left-sided motor weakness. An MRI of brain reveals small multifocal frontal and parietal subcortical white matter T2WI hyperintensities, and a few areas of restricted diffusion in the right cerebral hemisphere on DWI. What is the most likely diagnosis?

A. Multiple sclerosis (MS).

B. SLE.

C. Small vessel ischaemia.

D. Susac syndrome.

E. Lyme disease.

Answer 46

36. B. SLE.

The combination of white matter hyperintensities and focal infarcts (indicated by the areas of restricted diffusion) in combination with established neurology and neuropsychiatric symptoms, in a woman of child-bearing age, strongly suggests the diagnosis of cerebral lupus. SLE is an autoimmune disorder that affects many organ systems, including the CNS. Clinical presentation can include migraine, seizures, stroke, chorea, psychosis, mood disorder, acute confusional state, cognitive dysfunction, transverse myelopathy, cranial neuropathies, and aseptic meningitis. The CNS pathology includes vasculitis, dural venous sinus thrombosis, cerebritis, intracranial haemorrhage, infarction, and infection. Infarction can occur as a result of direct thrombosis as well as embolism from Libman–Sacks endocarditis. Diffuse neuropsychiatric symptoms are attributed to direct neuronal damage mediated by antibodies. The most common imaging finding is small multifocal T2WI or FLAIR hyperintense white matter lesions. Focal infarcts and grey matter lesions may also be seen, as well as diffuse steroid responsive subcortical lesions. Acute lesions may enhance. MR angiography and venography may show thrombotic lesions of vessels and dural venous sinus thrombosis, respectively. When a patient with SLE presents with an acute neurological deterioration, it is crucial to image them promptly: initially with unenhanced CT to exclude haemorrhage and then with MRI (including post-contrast sequences) to evaluate for stroke or abscess. Note that a negative brain MRI cannot exclude cerebral lupus. Treatment is immunosuppression, with anticoagulation for thrombotic events. Stroke is atypical for MS. Small vessel ischaemia should not occur in such a young age without an underlying cause and is not a satisfactory diagnosis. Susac syndrome is a triad of encephalopathy, branch retinal artery occlusions, and hearing loss. It is a microangiopathy of unknown aetiology and results in multiple T2WI hyperintense deep white matter and corpus callosum lesions. Lyme disease results in T2WI hyperintense periventricular white matter lesions, which may enhance, and it resemble ADEM or MS.

Question 47

58. A 56-year-old man with chronic alcohol dependence presents with progressive cognitive impairment, gait disturbance, and signs of interhemispheric disconnection. An MRI scan of brain demonstrates increased T2WI signal lesions without mass effect within the corpus callosum and dorsal part of the external capsule. Which of the following is the most likely diagnosis?

A. Wernicke’s encephalopathy.

B. Osmotic myelinolysis.

C. Marchifava–Bignami disease.

D. Alcohol withdrawal syndrome.

E. Chronic hepatic encephalopathy.

Answer 47

58. C. Marchifava–Bignami disease.

This is a rare complication of chronic alcohol consumption characterized by demyelination and necrosis of the corpus callosum, although other white matter tracts (such as the external capsule) may be involved. Bilateral and symmetrical T2WI hyperintensities within the thalami, periaqueductal grey, and mammillary bodies are seen in Wernicke’s encephalopathy. Osmotic myelinolyis is usually secondary to rapid changes in serum sodium and results in increased T2WI signal within the central pons. Extrapontine myelinolysis is rare. In alcohol withdrawal syndrome, patients present with seizures and delirium tremens. MRI may show volume loss in the temporal cortex and anterior hippocampus. Hepatic encephalopathy secondary to hepatocellular failure may produce T1WI hyperintensity within the caudate nucleus, globus pallidus, putamen, and anterior midbrain due to increased concentration of manganese.

Question 48

56. A 42-year-old male patient of African-Caribbean ethnicity presents to the neurologists with a history of facial paraesthesia and slight weakness, headache, lethargy, and neck stiffness. He also has a history of mild dyspnoea. An MRI is requested, which shows left frontal leptomeningeal thickening, with an apparent dural mass noted along the falx. There is increased T2WI/FLAIR signal in the cortex adjacent to this area of meningeal disease. There is also thickening and enhancement noted of the right trigeminal and facial nerves on post-contrast T1WI. Further enhancement is also noted along the parasellar region on the left. Multiple non-enhancing high T2WI/FLAIR periventricular white matter lesions are noted. Abnormality is noted in the skull vault, where there is an expanded diploic space over the right occipital region, with associated apparent thinning of the outer table, although this is hard to define on MRI. Due to concern with regard to multifocal meningioma the patient is started on steroids to reduce the mass effect from the frontal lesion and referred to neurosurgery. A CT is non-contributory. An MRI is repeated, which shows only mild meningeal thickening. What is most likely diagnosis?

A. NF-2.

B. Neurosarcoid.

C. Neurotoxoplasmosis.

D. Tuberous sclerosis.

E. Multiple sclerosis.

Answer 48

56. B. Neurosarcoid.

Whilst primary neurosarcoid is rare, it is not uncommon for the systemic disease to present via its neurological manifestations. The findings of neurosarcoid are non-specific, with the common manifestations mirroring those described in this patient. Leptomeningeal thickening and enhancement are classical. Involvement of the perivascular spaces adjacent to this can cause increased signal in the adjacent cortex. This appearance can mimic meningioma. Multifocal meningiomas and nerve sheath schwannomas are features of NF-2, but this would not be expected to resolve with steroid therapy. The features described are not typical of TS. The meningeal disease would make MS unlikely, even given the periventricular high-signal lesions, which are the most common intraparenchymal finding in neurosarcoid. Sarcoid involving the skull table is not directly related to the neurosarcoid and is more commonly seen with other manifestations of musculoskeletal sarcoid. Toxoplasmosis, in the absence of immunocompromise, is unlikely. Overall the response to steroid, along with the wide variation of CNS disease described, are the strongest indicators for sarcoid. Whilst neurosarcoid does typically respond well to steroid therapy, it has a high recurrence rate.

Question 49

60. An immunocompetent 24-year-old patient presents with an acute history of right-sided limb weakness which has rapidly progressed. The patient now also has mixed sensory symptoms and poorly controlled seizures. Basic observations and initial blood results are normal. An MRI is carried out which shows a large mass-like lesion in the right posterior frontal lobe. There is mild mass effect associated with this lesion on the adjacent parenchyma, with mild compression of the right lateral ventricle. The lesion is also noted to involve the corpus callosum and cross the midline into the left cerebral hemisphere. This lesion is bright on FLAIR imaging. On post-contrast T1WI the lesion has peripheral rim enhancement. Vascular structures are noted to pass through the lesion. There is no evidence of necrosis or haemorrhage. On DWI, the b1000 sequence reveals increased signal in the lesion. Other high T2WI lesions are noted in the cerebellum, with a further lesion in the spinal cord. What is the most likely diagnosis based on this information?

A. MS.

B. Glioblastoma multiforme.

C. High-grade astrocytoma.

D. Lymphoma.

E. Abscess.

Answer 49

60. A. MS.

The key feature in this clinical vignette is the identification of the mass lesion crossing the midline. Only a few lesions demonstrate this ability and they are GBM, lymphoma, metastases, MS and other white matter disorders, lipoma, stroke, and shearing injuries. Abscess is thus excluded and would be unlikely given the clinical features. GBM is unlikely given the absence of necrosis and would be rare in a patient of this age group. High-grade astrocytomas do not involve the corpus callosum and cross the midline. Lymphoma exhibiting these features would be uncommon in immunocompetent patients, being more typically associated with HIV-related lymphoma. Tumefactive MS typically presents with an acute clinical history and frequently displays the imaging features described. The presence of vascular structures crossing the lesion also indicates this diagnosis, as these would be displaced by neoplastic lesions.

Question 50

69. A 32-year-old man presents with schizophrenic-like psychosis and parkinsonian-type movement disorder. There is a family history of neuropsychiatric disturbance. An initial CT is requested which demonstrates heavy bilateral, symmetric calcifications within the globus pallidus, thalami, putamen, and cerebellum. There is no enhancement post contrast. Which of the following suggests a diagnosis of Fahr disease over pseudohypoparathyroidism?

A. Involvement of the globus pallidus.

B. Involvement of the thalami.

C. Involvement of the putamen.

D. Involvement of the cerebellum.

E. Normal calcium-phosphorus metabolism.

Answer 50

69. E. Normal calcium-phosphorus metabolism.

Fahr disease is a rare degenerative neurological disorder characterized by extensive bilateral basal ganglia calcifications that can lead to progressive dystonia, parkinsonism, and neuropsychiatric manifestations. CT has higher diagnostic specificity for basal ganglia calcification over MRI. The distribution of calcifications is similar in endocrinological disorders such as hyperparathyroidism, hypoparathyroidism, and pseudohypoparathyroidism. The calcium– phosphorus metabolism is usually normal in Fahr disease. In pseudohypoparathyroidism the serum calcium is low with an appropriately high parathyroid hormone (PTH), due to PTH resistance.

Question 51

70. A 29-year-old female complains of increasing headache, followed by generalized seizure activity 24 hours after giving birth. She is noted to be hypertensive. MRI demonstrates bilateral parieto-occipital T2WI hyperintense cortical and subcortical lesions. ADC is elevated. Similar lesions are noted in the anterior watershed zones. What is the most likely diagnosis?

A. Hypotensive cerebral infarction.

B. Postpartum cerebral angiopathy.

C. Posterior reversible encephalopathy syndrome (PRES).

D. Progressive multifocal leucoencephalopathy (PML).

E. Gliomatosis cerebri.

Answer 51

70. C. Posterior reversible encephalopathy syndrome (PRES).

This is a disorder of cerebrovascular autoregulation and is associated with eclampsia, which is defined clinically as seizure or coma with pregnancy-induced hypertension. There is a predilection for the posterior circulation and watershed zones, possibly due to its sparse vasomotor sympathetic innervation. T2WI hyperintense lesions within the posterior cortex and subcortical white matter, without diffusion restriction, are typical. Diffusion restriction/low ADC will be found in infarction. The diagnosis of postpartum cerebral angiopathy should be considered in normotensive postpartum women presenting with intracerebral haemorrhage. Reversible high T2WI signal abnormalities may also be seen in the cortex and subcortical white matter.
Multifocal stenoses and beading of the intracranial vasculature are also a feature. PML presents with asymmetrical T2WI hyperintensity in the periventricular and subcortical white matter, with cortical sparing. It is seen in the immunocompromised. Gliomatosis cerebri is a diffusely infiltrating tumour involving two or more lobes and is frequently bilateral. Enlargement of the involved structures is seen. It can mimic brainstem PRES.

Question 52

(Ped) 29 A seven-year-old girl presented with lethargy and headache two weeks after a viral infection. On examination she was irritable and febrile. She became increasingly drowsy and soon after admission had a generalised seizure. An MRI brain was performed which showed high signal lesions at the junction between the deep cortical grey matter and subcortical white matter on T2- weighted images. There was surrounding vasogenic oedema. Which of the following is the most likely diagnosis?

a Acute inflammatory demyelinating polyradiculoneuropathy

b Viral encephalitis

C Acute disseminated encephalomyelitis

d Primary CNS lymphoma

e Glioblastoma multiforme

Answer 52

29 Answer C: Acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis is a post-infectious encephalitis, usually following an exanthematous viral illness or vaccination. It is a diffuse inflammatory process leading to areas of demyelination caused by an autoimmune response to the patient’s white matter. Acute inflammatory demyelinating polyradiculoneuropathy is often called Guillain-Barre and does not cause changes in the brain.

Question 53

33 A 12 year old undergoing chemotherapy for acute myeloid leukaemia developed seizures. CT revealed multiple punctate areas of calcification scattered throughout the brain, with little enhancement and no mass effect. Ventricular size was normal. Comparison was made with a CT from two years previously which revealed no abnormality. What is the most likely diagnosis?

a Mineralising angiopathy

b Cytornegalovirus infection

C Fahr’s disease

d Toxoplasmosis

e Carbon monoxide poisoning

Answer 53

33 Answer A: Mineralising angiopathy

Mineralising angiopathy is widespread perivascular calcification which typically occurs in children receiving both irradiation and chemotherapy for acute leukaemia. The commonest sites include BG and junction of cortex and subcortical white matter.

Question 54

54 A 55-year-old chronic alcoholic was admitted following an extended period of heavy drinking. He was noted to be very confused, confabulating and suffering from delusions. On examination he was ataxic and had ophthalmoplegia. What features on MRI would you look for in order to make the diagnosis?

a Cerebellar atrophy

b High signal perpendicular to the lateral ventricle

C High signal within the periaqueductal region

d High signal within the vermis

e High signal within the lentiform nucleus

Answer 54

54 Answer C: High signal within the periaqueductal region

Chronic alcohol results in atrophy of the cerebellum, particularly the vermis. This patient has Wernicke’s encephalopathy, which is characterised by confabulation, delusions, ataxia, ophthalmoplegia and confusion and is caused by thiamine deficiency. High signal is seen in the periaqueductal region, paraventricular thalamic regions and mammillothalamic tract on MR imaging on FLAIR and T2W.

Question 55

55 A 35 year old presents with progressive personality changes and increasing withdrawal. CT brain demonstrated cerebral atrophy affecting the frontal lobes and anterior temporal lobe with associated compensatory enlargement of the frontal horns of the lateral ventricles. The rest of the brain was normal. What is the likely diagnosis?

a Alzheimer’s disease

b Parkinson’s disease

C Progressive supranuclear palsy

d Fabry’s disease

e Pick’s disease

Answer 55

55 Answer E: Pick’s disease

Striking disproportional atrophy of the frontal and anterior temporal lobes in a young patient is typical of Pick’s disease, which is also known as frontotemporal atrophy. In Alzheimer’s disease there is medial temporal lobe atrophy with compensatory enlargement of the temporal horns. Parkinson’s disease results in a generalised cerebral atrophy. Progressive supranuclear palsy results in atrophy of the midbrain, globus pallidus and frontal lobes.

Question 56

56 A 39-year-old man was being investigated for progressive involuntary movement. On CT he was found to have caudate atrophy with compensatory enlargement of the anterior horns of the lateral ventricles. What would one expect to see on MRI imaging?

a Eye of the tiger sign

b High signal in the caudate and putamen on T2-weighted MR images

C High signal in the thalamus on T2-weighted MR images

d Loss of the pars compacta

e High signal in the pons on T2-weighted MR images

Answer 56

56 Answer B: High signal in the caudate and putamen on T2-weighted MR images

This patient has Huntington’s chorea which has autosomal-dominant inheritance and is characterised by involuntary choreoathetoid movements and severe memory impairment. The age at which symptoms occur is dependent on the length of the trinucleotide CAG-repeat mutation on chromosome 4, but is typically around 40 years. On imaging there is bilateral atrophy of the caudate lobe with compensatory enlargement of the frontal horns of lateral ventricles. High signal is seen within the caudate and putamen in the juvenile form.

Question 57

57 A 63-year-old male undergoing a CT for unwitnessed fall had marked widening of the cerebellar sulcal spaces suggestive of cerebellar atrophy. Which of the following is unlikely to be a cause?

a Phenytoin

b Alcohol

C Ataxia telangiectasia

d Tuberous sclerosis

e Bronchial carcinoma

Answer 57

57 Answer D: Tuberous sclerosis

Phenytoin, alcohol, ataxic telangiectasia and paraneoplastic syndrome from a bronchial tumour all result in cerebellar atrophy. Other causes are marijuana, steroids, radiation, multisystem atrophy and gluten insensitivity.

Question 58

58 A 17-year-old boy was being investigated for partial complex seizures refractory to drug treatment and was being considered for a lobectomy. An interictal FDG-PET scan demonstrated reduced signal in the right temporal lobe. What would be the next appropriate step in management?

a Continue with medical management

b Perform an ictal FDG-PET scan

C Right temporal lobe resection

d Left temporal lobe resection

e Radiotherapy

Answer 58

58 Answer C: Right temporal lobe resection

This patient has temporal lobe epilepsy caused by mesial temporal sclerosis. On MRI there is atrophy of the hippocampus, amygdala, mammillary bodies and fornix. High signal within the hippocampus is seen on T2-weighted imaging which may be bilateral in 20% of cases. Nuclear medicine imaging can be used to diagnose the site of the epilepsy focus. On interictal FDG-PET imaging there is decreased uptake of radiotracer at the site of fit focus. On ictal SPECT scanning there is increased uptake of tracer at the focus of the fit. If epilepsy is refractory to antiepileptics, a temporal lobectomy can be performed. Approximately 50% of all temporal lobe resections are for epilepsy.

Question 59

53 A 40-year-old female was being investigated for a familial movement disorder. On CT of her brain there was caudate atrophy with compensatory enlargement of the frontal horns of the lateral ventricles. How is this condition inherited?

a X-linked recessive

b X-linked dominant

C Autosomal dominant

d Autosomal recessive

e Not inherited

Answer 59

53 Answer C: Autosomal dominant

This patient has Huntington’s disease, which is an autosomal dominantly inherited disease. The age at which symptoms occur is dependent on the length of the trinucleotide CAG repeat sequence.

Question 60

54 A 15-year-old girl with a neurocutaneous disorder had an MRI which showed vermian and interhemispheric atrophy with compensatory enlargement of the Nth ventricle. There were also multiple small cortical wedge infarcts. What cutaneous abnormalities is she most likely to have?

a Cafe au lait spots

b Axillary freckles

c Telangiectasia

d Port wine stain

e Adenoma sebaceum

Answer 60

54 Answer C: Telangiectasia

Ataxic telangiectasia is an autosomal recessive disease, which is characterised by multiple telangiectasia, cerebellar ataxia, pulmonary infections and immunodeficiency. Brain imaging demonstrates vermian atrophy, cerebral infarcts and cerebral haemorrhage secondary ruptured telangiectatic vessels. Patients are susceptible to upper respiratory infections and malignancy such lymphoma and leukaemia in children. Adults have a very high incidence of breast and bowel cancers.

Question 61

55 A 22-year-old Australian gap year student started to develop unusual behaviour, dystonia and dysarthria while travelling around Europe. On MRI she was found to have high signal in the caudate and putamen. There were no mass lesions, hydrocephalus or extra axial blood. What is the most likely diagnosis?

a Wilson’s disease

b Ataxic telangiectasia

C Leigh’s disease

d Carbon monoxide poisoning

e HIV

Answer 61

55 Answer A: Wilson’s disease

Wilson’s disease is an autosomal recessively inherited condition, which results in abnormal caeruloplasmin metabolism. Copper is deposited within the liver, cornea and brain. Dysarthria, dystonia and tremors are commonly early clinical findings. On imaging there is atrophy of the caudate lobe and high signal within the outer margin of the putamen, caudate and lateral aspect of the thalami. High signal is often seen within the pons. Treatment is with a collating agent.

Question 62

57 A 35-year-old woman is being investigated for demyelinating disease. What is the best sequence to demonstrate plaques in the posterior fossa?

a Axial T2

b Coronal FLAIR

C Axial proton density

d Axial FLAIR

e Coronal Ti

Answer 62

57 Answer A: Axial T2

FLAIR and T2 sequences are good at identifying MS plaques. T2 sequences are better at identifying lesions within the spinal cord and posterior fossa.

Question 63

59 A 30-year-old West African woman was being investigated for a right Bell’s palsy and diabetes insipidus. She was known to have an abnormal CXR. On MRI she was found to have diffuse meningeal enhancement with some modularity. What would be your next investigation?

a Repeat CXR

b CT brain

C Meningeal biopsy

d Staging CT

e Full blood count

Answer 63

59 Answer C: Meningeal biopsy

This patient has sarcoid, which is most common is females and West Africans and the most common presentation is with bihilar lymphadenopathy. The CNS is affected in 1-8% of patients with sarcoid. The leptomeninges, dura, subarachnoid space, peripheral nerves and ventricular system are affected and the most common findings are cranial neuropathies with the facial and acoustic nerves being the most commonly affected. Patients can present with aseptic meningitis, fits and MS-like plaques. On imaging there is diffuse enhancement of the meninges, which is sometimes nodular and is most common in the basal cisterns, but can affect any region. Hydrocephalus may be present and small vessel change can occur. Definitive diagnosis is made by meningeal biopsy and ACE levels may not be raised.

Question 64

8 A patient with suspected Alzheimer’s presents with memory impairment, personality change and mild but definite cogwheel rigidity. The referrer is keen to start Alzheimer’s therapy soon due to the high clinical suspicion and success rate of early therapy. Out of the following options, which is the best investigation to ensure therapy will not exacerbate a Parkinsonian crisis?

a CT scan

b DaTSCAN

C Tc-99m HMPAO brain scan

d MRI scan

e PET-CT with FDG

Answer 64

8 Answer B: DaTSCAN

Schizophrenia therapy can produce Parkinson’s-like symptoms and if there are equivocal changes on the DaTSCAN, treatment should be used with caution. The only way to assess presynaptic receptors for dopaminergic uptake is with a DaTSCAN.

Question 65

13 A 68-year-old male with no previous psychiatric history was referred with declining memory and confusion. A CT showed patchy low density in the deep white matter with marked generalized atrophy and multiple small well-defined areas of low density, which lacked mass effect. He was then referred for a radionuclide HMPAO scan which demonstrated reduced perfusion to the superior parieto-temporal cortices bilaterally. What is the most likely diagnosis?

a Frontotemporal dementia with concurrent vascular disease

b Alzheimer’s disease/DLB (dementia of the Lewy body type) probably secondary to vascular pathology

C A mixed pattern of Alzheimer’s/DLB type and vascular dementia

d Drug-induced Parkinson’s disease

e Mesial temporal sclerosis

Answer 65

13 Answer C: A mixed pattern of Alzheimer’s/DLB type and vascular dementia

Alzheimer’s and dementia of the Lewy body type do not have a vascular aetiology but may coexist with vascular dementia. Mesial temporal sclerosis is a form of epilepsy diagnosed clinically and is best imaged on MRI. Frontotemporal dementia presents differently and imaging shows frontal and temporal lobe changes.

Question 66

15 A 66-year-old man with a history of chronic schizophrenia, for which he receives medication, presents to the neurologists with recent onset tremor and apathy. A DaTSCAN shows bilateral `comma-shaped’ tracer uptake in the striatal pathways. CT shows ill-defined low density in the periventricular deep white matter with a mild degree of atrophy. What is the most appropriate preliminary diagnosis at this stage?

a Idiopathic Parkinson’s disease

b Vascular dementia

C Drug-induced Parkinsonian syndrome

d Early-onset Alzheimer’s disease

e Depression

Answer 66

15 Answer C: Drug-induced Parkinsonian syndrome

The DaTSCAN is normal hence there is no evidence of idiopathic Parkinson’s disease, but this study will not exclude drug-induced symptoms, which are caused by blockade of postsynaptic receptors. The treatment of schizophrenia includes drugs, which can produce a Parkinson’s-like syndrome. Early-onset Alzheimer’s refers to patients under 60 years old; the symptoms and investigation are not compatible with this diagnosis. Depression is also feasible.

Question 67

(Ped) 26 A two-year-old child is under investigation for delayed walking and widebased gait. Their speech is difficult to understand. There is a history of recurrent chest infections. A CT brain is performed, which demonstrates cerebellar cortical atrophy and dilatation of the fourth ventricle. There is also a cerebral infarct. What is the most likely diagnosis?

a Friedreich’s ataxia

b Ataxia telangiectasia

C Multiple sclerosis

d Wolman disease

e Niemann-Pick disease

Answer 67

26 Answer B. Ataxia telangiectasia

Ataxia telangiectasia is a rare autosomal-recessive disorder characterised by telangiectasias, cerebellar ataxia, sinus and pulmonary infections, immunodeficiencies and increased risk of developing malignancies. Cerebral infarcts are caused by emboli shunted through the vascular malformations in the lung. Ruptured telangiectatic vessels can cause cerebral haemorrhage. Wolman disease is a very rare autosomal-recessive lipid storage disease, which is almost always fatal in the first year of life. Friedreich’s ataxia shows atrophy of the cervical spinal cord but the cerebellum is usually spared. Multiple sclerosis shows plaques within the brain and cerebral atrophy, not cerebellar atrophy. Niemann-Pick disease is lipid storage disorder; there are multiple sub-types, most of which would have been fatal by the age of presentation of this child and there is also no imaging CNS abnormalities involved.

Question 68

32 A 55-year-old male was brought in unconscious following a house fire. He was intubated and had a CT head, which was unremarkable. Three days later he did not regain consciousness and an MRI head was performed. This showed low signal intensity on T1-weighted images and high signal on T2-weighted and FLAIR images within the medial portions of the globus pallidus bilaterally. What is the most likely diagnosis?

a Hypoxic ischaemic encephalopathy

b Carbon monoxide poisoning

C Central pontine myelinolysis

d Venous infarction

e Wilson’s disease

Answer 68

32 Answer B: Carbon monoxide poisoning

Carbon monoxide poisoning is a leading cause of accidental poisoning. In the brain CO has a predilection for the globus pallidus. On CT there is symmetric hypodensity while on MRI the medial portions of the globus pallidus appear as areas of low signal on Ti and high signal on T2 and FLAIR images. The caudate nucleus, putamen and thalamus are occasionally involved. The differentials include Wilson’s disease and cyanide poisoning.

Question 69

33 A 55-year-old female was admitted with a short history of headache and drowsiness. She was found to be hypertensive with a BP of 220/140.On ophthalmoscopy she was found to have grade IV papilloedema. PRES was suspected clinically. What features would be expected on CT?

a Periventricular low-density white matter changes perpendicular to the lateral ventricles

b Low-density white matter changes within the occipital lobes

c Intraparenchymal haemorrhage affecting the basal ganglia

d Low-density changes affecting the cerebellar white and grey matter

e Diffuse bilateral asymmetrical perivenous low-density changes

Answer 69

33 Answer B: Low-density white matter changes within the occipital lobes

The imaging pattern of PRES is seen in eclampsia, cyclosporin toxicity following transplantation, autoimmune disorders like SLE and Wegener’s and in hypertension. The exact cause is unproven but an unstable blood pressure is a frequent finding. Typical findings in PRES include reversible vasogenic oedema in the parieto-occipital, posterior frontal and cortical and subcortical white matter. The cerebellum and brainstem are less commonly involved. Haemorrhage and restricted diffusion on DWI are atypical.

Question 70

41 A 14-year-old girl presented after her parents became aware that her walking was slower than usual and she kept tripping over. On examination she had an ataxic gait and bilateral reduction in toe proprioception. MRI brain and spinal cord were performed and showed atrophy of the cervical spinal cord without evidence of cerebellar atrophy. Which of the following is the most likely diagnosis?

a Ataxia telangiectasia

b Guillain-Barre syndrome

C Multiple sclerosis

d Friedreich’s ataxia

e Joubert syndrome

Answer 70

41 Answer D: Friedreich’s ataxia

Friedreich’s ataxia is the most common inherited progressive ataxia. It usually presents before adolescence. cerebellum is atrophied in ataxia telangiectasia and cerebrum is atrophied in multiple sclerosis. Guillain-Barre not produce any Cx changes.

Question 71

52 A 32-year-old Caucasian female was scanned following worsening weakness of the lower limbs. Several discrete oval and round lesions were identified in the periventricular white matter perpendicular to the ventricles on MRI. A sample of CSF confirmed the diagnosis made on MRI. Which of the following is not a usual feature of this condition?

a Cortical lesions

b Haemorrhage

C Ring enhancement

d Corpus callosal involvement

e Periventricular extension

Answer 71

52 Answer B: Haemorrhage

Demyelisation lesions in multiple sclerosis typically occur in the periventricular region, perpendicular to the ventricle. Lesions can occur anywhere in the brain and affect both grey and white matter. Ring enhancement occurs up to six weeks after the occurrence of the plaque. Haemorrhage is not a feature.

Question 72

53 A middle-aged alcoholic man was admitted with a reduced level of consciousness and quadriplegia. He had been discharged a few days earlier when he was noted to have a low sodium. On the most recent admission he had a CT, which appeared normal. A MRI, however, demonstrated a butterfly-shaped area of high signal in the pons on T2 and FLAIR images. Similar lesions were also seen in the thalami. What is the most likely diagnosis?

a Brainstem glioma

b Central pontine myelinolysis

C Multiple sclerosis

d Gliomatosis cerebri

e Venous infarction

Answer 72

53 Answer B: Central pontine myelinolysis

Central pontine myelinolysis or osmotic demyelination syndrome is acute demyelination secondary to rapid correction of a hyponatraemia. It commonly occurs in diabetic patients with diabetic ketoacidosis, anorexics and alcoholics. However, less common causes are SIADH, Wilson’s and craniopharyngioma. Patients develop symptoms a few days following the correction of the electrolyte imbalance and presentation is varied from unconscious (locked in syndrome), spastic quadriparesis and pseudobulbar palsy or with extrapyramidal signs. High signal is seen within the pons on FLAIR and T2 W usually after a couple of weeks. There may be high signal in the basal ganglia and this is typically bilateral and symmetrical. Prognosis is very poor with a mortality of approximately 90%.

Question 73

7. A chronic alcoholic was admitted with dehydration, acute confusion and electrolyte imbalance. The patient was admitted and treated vigorously with intravenous fluids. The next day the patient went into a coma. MRI shows a round abnormality in the central area of the pons which returns low signal on T1 and high on T2. The most likely cause of the abnormality is?

(a) Acute pontine infarct

(b) Pontine haemorrhage

(c) Wilson’s disease

(d) Glioma

(e) Central pontine myelinolysis

Answer 73

7. (e) Pontine myelinolysis

Also known as osmotic myelinolysis. This condition is seen in people with rapidly corrected hyponatraemia with intravenous fluids. The rapid correction of sodium releases myelinotoxic compounds resulting in destruction of myelin sheaths. This is particularly common in alcoholics.

Question 74

27. A 60-year-old man with a history of chronic alcoholism is admitted with confusion and dysarthria. MRI shows a 2 cm area of abnormality in the central pons which returns high T2 signal and low on T1. There is a rim of normal tissue around this lesion and prominence of the cerebellar folia. What is the most likely diagnosis?

(a) Multiple sclerosis

(b) Central pontine myelinosis

(c) Infarction

(d) Neoplasm

(e) Acute disseminated encephalomyelitis

Answer 74

27. (b) Central pontine myelinosis

This is characterised by a symmetrical, non-inflammatory demyelination of the basis pontis. The underlying cause is rapidly corrected hyponatraemia. MRI appearances are characteristic with a spari

Question 75

36. A 35-year-old woman with spastic paraparesis presents with an episode of right facial paralysis. FLAIR axial images show multiple foci of hyperintense signal in the periventricular distribution, aligned at a right angle to the ventricles. Contrastenhanced T1 images of cervical spine show multiple enhancing lesions in the cervical cord. What is the most likely diagnosis?

(a) Diffuse axonal injury

(b) Small vessel ischemic change

(c) Vasculitis

(d) Multiple sclerosis

(e) Neurosarcoidosis

Answer 75

36. (d) Multiple sclerosis

MS typically produces multiple white matter lesions that are hyperintense on T2 and FLAIR. Characteristically, these lesions are aligned at right angles to ventricles. Contrast enhancement may be seen in active lesions.

Question 76

38. A 52-year-old man with a history of previous treated arteriovenous malformation in brain presents with bilateral sensorineural hearing loss. MRI of the brain shows that the contours of brain outlined by hypointense rim on T2 and T2* GRE images. What is the most likely diagnosis?

(a) Central nervous system siderosis

(b) MR sequence artefacts

(c) Brain surface vessels

(d) Neurocutaneous melanosis

(e) Meningoangiomatosis

Answer 76

38. (a) Central nervous system siderosis

Recurrent subarachnoid bleeds cause haemosiderin deposition on the surface of the brain, brainstem and leptomeninges

Question 77

5. Which of the following statements are correct about MRI features of multiple sclerosis: (T/F)

(a) Corpus callosum lesions are best visualized on axial view.

(b) T2W spin echo is superior to FLAIR for posterior fossa lesions.

(c) Whiter matter lesions are more conspicuous than grey matter lesions.

(d) Ring enhancement on post gadolinium T1W MRI suggests an alternative diagnosis.

(e) 10-15 % of patients have lesions limited to the spinal cord.’

Answer 77

Answers:

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

Explanation:
MS plaques are classically seen in periventricular and juxtacortical white matter. Involvement of corpus callosum is characteristic and is best seen on Sagittal images. Both solid and ring enhancement may occur. Incomplete ring enhancement is seen in larger MS plaques.