VIQ - CNS Flashcards
@# 24. Which of the following best describes the typical appearance of intracranial haemorrhage in the late subacute phase (8-30 days)?
A. Increased T1, decreased T2
B. Isointense T1, decreased T2
C. IsointenseT1, increased T2
D. Increased T1, increased T2
E. Decreased T1, decreased T2
D. Increased T1, increased T2
A represents early subacute haemorrhage,
B represents acute (12-72 hours),
C represents hyperacute (less than 12 hours)
and E represents chronic haemorrhage (> 1 month).
@# 8) A 62-year-old man with a history of falls and confusion undergoes MR of the brain. This demonstrates a subdural haematoma of high signal intensity on T1W images and of high signal intensity with a hypointense rim on T2W images. What is the most likely age of the haematoma?
a. ,6 hours
b. 8–72 hours
c. 3 days to 1 week
d. 1 week to several months
e. several months to several years
d. 1 week to several months
In the first 3–6 hours (hyperacute stage) following haemorrhage, the intact red cells contain mostly oxyhaemoglobin, which appears hyperintense on T2W images.
Desaturation occurs peripherally, forming deoxyhaemoglobin, which is seen as hypointensity on T2W images.
In the acute stage (8–72 hours), there is rapid deoxygenation of the oxyhaemoglobin to deoxyhaemoglobin, which, together with the high protein content of the clot and susceptibility effects, results in isoto hypointensity on T1W images and hypointensity on T2W images.
In the early subacute stage (37 days), oxidation of deoxyhaemoglobin to methaemoglobin occurs inside the red cell, resulting in characteristic hyperintensity on T1W images due to paramagnetic effects, and marked hypointensity on T2W images.
In the late subacute stage (1 week to months), extracellular methaemoglobin results in persistent hyperintensity on T1W images, but increasing signal intensity on T2W images, with peripheral susceptibility effects causing a low intensity rim.
In the chronic stage (months to years), iron atoms are deposited as haemosiderin and ferritin, which cause susceptibility effects resulting in low signal intensity on both T1W and T2W images.
@# 34) An unenhanced CT scan of the brain is performed 3 hours after the onset of signs suggestive of ischaemic stroke. Which of the following image window parameters is most likely to reveal the early CT changes?
a. width 400 HU, centre 40 HU
b. width 80 HU, centre 20 HU
c. width 8 HU, centre 32 HU
d. width 0 HU, centre 0 HU
e. width 1500, centre –500 HU
c. width 8 HU, centre 32 HU
Loss of grey–white matter differentiation, obscuration of the lentiform nucleus and the insular ribbon sign are manifestations of cytotoxic oedema that can be seen on CTas early as 2 hours after middle cerebral artery infarction. With normal window settings (width 80 HU, centre 20 HU), the sensitivity and specificity for acute ischaemic stroke detection on unenhanced CT are 57% and 100% respectively.
The sensitivity is improved to 71% with window settings of width 8 HU and centre 32 HU.
This setting accentuates the difference between normal and oedematous brain tissue.
@# 43) A patient with multiple previous ischaemic strokes has an MRI including T2W and DWI sequences. In the left frontal lobe, there is a region of increased T2 signal. The same area is dark on the DWI and bright on the ADC map. Which of the following is the most likely age of this region of ischaemia?
a. 10 minutes
b. 30 minutes
c. 3 days
d. 2 weeks
e. 4 months
e. 4 months
The imaging findings are in keeping with a chronic infarct, in which the unrestricted extra water within gliosis gives a high T2 signal, dark DWI and bright ADC.
Cytotoxic oedema occurs because of early ischaemic damage to the cell membrane Na+/K+ ATPase pump. This can be seen as early as 30 minutes after symptom onset as a bright DWI region. T2W images will be normal this early and the corresponding ADC map dark.
DWI signal increases during the first week due to restricted diffusion but may remain bright for a prolonged period due to T2 ‘shine-through’. ADC will return to normal at 1–4 weeks (pseudonormalization) when restricted diffusion is matched by increasing amounts of vasogenic oedema that is not restricted.
Long-term gliosis has extra water that is not restricted. DWI can be usefully thought of as a T2 signal diminished by net water movement. Since the DWI can be bright because of T2 ‘shine-through’ rather than restricted diffusion, comparison of DWI findings with the ADC map is mandatory.
@# 18 An elderly, hypertensive man is found collapsed. CT imaging demonstrates a large intracerebral haematoma. The mean CT attenuation is 70 HU, and there are fluid/ fluid levels. How old is the haematoma likely to be?
(a) 0-2 hours
(b) 3-48 hours
(c) 3-7 days
(d) 2-4 weeks
(e) 2 months
(b) 3-48 hours
@# 47 A pregnant lady patient presents with headache and a focal neurological deficit. A non-enhanced CT shows increased attenuation in the superior sagittal sinus. Following the administration of intravenous contrast medium, the dura surrounding the sinus enhances but the sinus itself does not. MR imaging is performed. Given the most likely diagnosis, which appearances would be unusual for this condition?
(a) Low T2W signal intensity at 2 days
(b) lso/high T1W signal intensity in 20 days
(c) High T1W signal intensity in 10 days
(d) Low T2W signal intensity in 20 days
(e) High T2W signal intensity in 10 days
(d) Low T2W signal intensity in 20 days
This patient has suffered a venous sinus thrombosis.
The pattern of signal intensities is as follows:
Acute (< 5 days): T1W isointense, T2W low;
Subacute: T1W high, T2W high;
Chronic: T1W isointense/ high, T2W, isointense/ high.
@# 32 An elderly gentleman has an episode of amaurosis fugax and undergoes Doppler ultrasound assessment of his carotid arteries. Which of the following features is not an indication of either internal carotid artery or common carotid artery stenosis?
(a) Peak systolic velocity of 160 cm/s
(b) Significant quantities of visible plaque
(c) End diastolic velocity of 120 cm/s
(d) Spectral broadening
(e) ICA/ CCA peak systolic velocity ratio of 1.5
(e) ICA/ CCA peak systolic velocity ratio of 1.5
A consensus panel has recently defined the US criteria for gauging carotid artery stenosis. Quantitative criteria include: (table)
@# 35 An elderly, hypertensive man is found collapsed. MR imaging demonstrates a large intracerebral haematoma, with intermediate. signal intensity on T1W and high signal intensity on T2W. How old is the haematoma likely to be?
(a) 0-12 hours·· ·
(b) 12-72 hours
(c) 4-7 days
(d) 8-30 days c
(e) More than 1 month
(a) 0-12 hours
@# 38 An elderly, hypertensive man was found collapsed. MR imaging reveals a large infarct, with low signal intensity on T1W, high signal intensity on T2W, high signal on DWI and low signal on the ADC map. How old is the infarct likely to be?
(a) 0-6 hours
(b) 6 hours to 4 days
(c) 4-14 days
(d) 14-30 days
(e) More than 1 month
(b) 6 hours to 4 days
@# 6. A 52-year-old man is investigated by MRI of brain for a possible transient ischaemic attack (TIA). Focal lesions of CSF signal intensity are identified adjacent to the anterior commissures. The referring neurologist suspects that these lesions are chronic lacunar infarcts. What MRI finding suggests prominent perivascular space?
A. No restricted diffusion on DWI.
B. Hypointense on T1WI.
C. Hyperintense on T2WI.
D. Suppress on FLAIR.
E. Normal surrounding brain parenchyma.
- E. Normal surrounding brain parenchyma.
Perivascular spaces (Virchow–Robin spaces) are pial lined interstitial fluid structures that accompany penetrating arteries, but do not communicate directly with the subarachnoid space. They can occur anywhere, but typically cluster around the anterior commissure. They follow CSF signal intensity, suppress on FLAIR, and do not exhibit restricted diffusion. They can occasionally be giant when located within the midbrain.
Lacunar infarcts will also be hypointense on T1WI and hyperintense on T2WI. Restricted diffusion will be seen when acute/subacute. They are typically of increased signal on FLAIR, although will suppress if there is central encephalomalacia. A halo of surrounding high signal on T2WI and FLAIR is typical of lacunar infarction, although up to 25% of prominent perivascular spaces can also demonstrate a slight halo of increased signal. Lacunar infarcts are also more typically seen more extensive white matter disease.
@# 8. A 32-year-old man presents with recent onset of migraine and TIAs. He also reports some cognitive decline. Cerebral angiogram is normal. An MRI of brain reveals discrete hyperintensities in the anterior temporal poles and external capsules. What is the most likely diagnosis?
A. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).
B. Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke (MELAS).
C. Myoclonic epilepsy with ragged red fibres (MERRF).
D. Sporadic subcortical arteriosclerotic encephalopathy (sSAE).
E. Protein S deficiency.
- A. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL).
This is a hereditary small vessel disease, which causes stroke in young adults.
The genetic mutation is found on chromosome 19.
Presentation can include migraine, cognitive decline, psychiatric disturbance, TIAs, and stroke, the latter usually with substantial/complete recovery after individual strokes, particularly early in the disease process.
Imaging reveals subcortical lacunar infarcts and leukoencephalopathy in young adults.
The frontal lobe has the highest lesion load, followed by the temporal lobe and insula.
Anterior temporal pole and external capsule lesions have higher sensitivity and specificity for CADASIL.
The cerebral cortex is usually spared.
MRI is the investigation of choice: CT will reveal only areas of hypodensity and angiography is normal.
sSAE is associated with hypertension and results in multiple lacunar infarcts in the lenticular nuclei, pons, internal capsule, and caudate nuclei.
MELAS and MERRF are mitochondrial disorders.
MELAS results in bilateral multiple cortical and subcortical hyperintense lesions on FLAIR images;
MERRF has a propensity for the basal ganglia and caudate nuclei, and watershed ischaemia/ infarcts are common.
Hypercoagulable states such as protein S deficiency result in cortical and lacunar infarcts of various sizes, but the cerebral angiogram is abnormal.
@# 62. A 36-year-old man is admitted following a seizure. Unenhanced CT demonstrates a right frontal mixed attenuation lesion, which avidly enhances post contrast. Multiple flow voids are seen on MRI of brain. What finding on catheter angiography differentiates arteriovenous malformation (AVM) from other vascular lesions of the brain?
A. Early venous drainage.
B. Arterial stenoses of feeder vessels.
C. External carotid transdural supply.
D. Dilated medullary veins (caput medusa).
E. Dilated cortical veins.
- A. Early venous drainage.
Brain AVMs are abnormal connections between arteries that would normally supply the brain tissue and veins that normally drain the brain, resulting in shunting with an intervening network of vessels within the brain parenchyma.
The finding of early venous drainage is important in differentiating brain AVMs from other vascular lesions.
Cortical venous drainage may be seen in superficial lesions.
Recruitment of transdural supply is observed in large lesions, although this is a more typical feature of proliferative angiopathy, which is a diffuse type of AVM.
Classically, in this condition, normal brain parenchyma is interspersed between the abnormal vessels.
Stenoses of feeder vessels are also often identified in proliferative angiopathy.
The caput medusa of dilated medullary veins is a feature of DVAs, a normal variant.
Dilated cortical veins are seen in dural arteriovenous fistulas (DAVFs), which are abnormal connections between arteries that normally supply the meninges (but not the brain) and small venules within the dura.
@# 40) A 35-year-old man is involved in a low-velocity road traffic accident. Within minutes, he experiences an occipital headache and neck pain. On arrival in hospital, he complains of nausea, vertigo and diplopia. An unenhanced CT scan of the brain is performed. Which of the following abnormal findings is most likely?
a. high density seen in CSF of the sylvian fissure
b. low density and loss of grey–white matter differentiation in the insular region
c. expansion of a vertebral artery with a peripheral, high-density crescent
d. lenticular high attenuation between the temporal lobe and temporal bone
e. crescent-shaped high attenuation between the temporal lobe and temporal bone
c. expansion of a vertebral artery with a peripheral, high-density crescent
Minor trauma stretching the vertebral artery over the lateral mass of C2 can cause vertebral artery dissection.
Symptoms include headache and neck pain, and as many as 95% of patients develop a stroke after hours to weeks. Imaging will show an axially enlarged vessel with a narrow lumen and a periarterial rim sign.
Angiography may demonstrate tapering or occlusion of the artery or the dissection flap.
Predisposing factors to spontaneous arterial dissection include fibromuscular dysplasia, Marfan’s syndrome, collagen vascular disease and homocysteinuria.
@# 69) In the presence of raised intracranial pressure, the anterior cerebral artery is at risk of compression during which of the following types of brain herniation?
a. transforaminal herniation
b. sphenoid herniation
c. ascending transtentorial herniation
d. descending transtentorial herniation
e. subfalcine herniation
e. subfalcine herniation
Transtentorial herniation may be descending (towards the posterior fossa) or ascending (upward displacement of the cerebellum through the tentorial incisura).
Descending transtentorial herniation causes shift of the temporal lobe over the tentorium, which may compress the third cranial nerve, the posterior cerebral and anterior choroidal arteries, and the midbrain.
Contralateral hemiparesis may occur due to compression of the ipsilateral cerebral peduncle.
Ipsilateral hemiparesis may also occur due to compression of the contralateral cerebral peduncle against the tentorial edge (Kernohan’s notch phenomenon, a false localizing sign).
Subfalcine herniation occurs when the cingulate gyrus shifts beneath the falx, due to medially directed supratentorial mass effect. This may cause compression of the anterior cerebral artery (resulting in ipsilateral distal anterior cerebral infarction) and internal cerebral veins.
Sphenoid herniation involves herniation of the frontal lobe posteriorly across the edge of the sphenoid ridge, and rarely produces significant clinical symptoms.
Transforaminal herniation results in herniation of the inferior cerebellum downward through the foramen magnum, which can result in obtundation and death.
@# 1 A young man presents with a thunderclap headache. A CT examination is performed. Sub-arachnoid blood is seen with a localised clot which has a maximum thickness of 2 mm. No intraventricular nor parenchymal blood is seen. What is the Fisher Grade?
(a) Grade 0
(b) Grade I
(c) Grade II
(d) Grade Ill
(e) Grade IV
(d) Grade Ill
The Fisher scale is useful in communicating the description of SAH.
Grade 1: no haemorrhage evident,
grade 2: SAH < 1 mm,
grade 3: SAH > 1 mm,
grade 4: associated intra-ventricular haemorrhage or parenchymal extension.
@# 12. Which of the following best represents the decline in positive CT findings for a clinically suspected subarachnoid haemorrhage from scanning at 12 hours post-ictus to 3 days post-ictus?
a. 90% positive at 12 hours to 70% positive at 3 days
b. 90% positive at 12 hours to 60% positive at 3 days
c. 98% positive at 12 hours to 90% positive at 3 days
d. 98% positive at 12 hours to 75% positive at 3 days
e. 90% positive at 12 hours to 50% positive at 3 days
12.d. 98% positive at 12 hours to 75% positive at 3 days
@# 9. Which brain tumour has the greatest incidence across all age groups?
A. Meningioma
B. Metastases
C. Pituitary adenoma
D. Haemangioblastoma
E. Glioma
E. Glioma
Gliomas consist of astrocytomas, oligodendrogliomas, paragangliomas, ganglogliomas and medulloblastomas
@# 23. Which is the most common location of oligodendroglioma?
A. Temporal lobe
B. Parietal lobe
C. Occipital lobe
D. Frontal lobe
E. Cerebellum
D. Frontal lobe
Most commonly involve cortical & subcortical white matter, occasionally through CC as butterfly glioma.
@# 60) Which of the following is the most common radiation-induced CNS tumour?
a. ependymoma
b. oligodendroglioma
c. lymphoma
d. glioblastoma multiforme
e. meningioma
e. meningioma
Meningioma is the most common radiation-induced CNS tumour, and has been particularly associated with low-dose radiation treatment for tinea capitis.
For the diagnosis of radiation-induced meningioma to be made, the meningioma must arise in the radiation field, appear after a latency period of years and should not have been the primary tumour irradiated.
Radiation-induced meningiomas are more frequently multiple and have higher recurrence rates than non-radiation-induced tumours.
@# 26 An elderly man is admitted for assessment of focal neurological symptoms. An incidental supratentorial cystic lesion is demonstrated. Which of the following features would make the diagnosis of subdural hygroma, rather than arachnoid cyst, more likely?
(a) Isointense to CSF on T1W MR imaging
(b) Mass effect
(c) Isointense to CSF on T2W MR imaging
(d) Flattened sulci
(e) Bony remodeling
(e) Bony remodeling
Scalloping of the adjacent bone, possibly through transmitted pulsations, is often seen in arachnoid cysts. This is never seen in subdural hygromas, but can be seen with epidermoid cysts or porencephaly.?
@# (CNS) 9 A plain radiograph is performed on a male child. Unilateral, premature fusion of both the coronal and lambdoid sutures is evident. What is the most appropriate description?
(a) Scaphocephaly
(b) Brachycephaly
(c) Plagiocephaly
(d) Trigonocophaly
(e) Oxycephaly
(c) Plagiocephaly
The common craniosynostoses include:
