Thrall chapter 12 MRI features of brain disease in small animals

Question 1

2) Which statement is correct with respect to gadolinium (can be more than one)?
a) Gadolinium results in T1 shortening of tissue in which it accumulates resulting in an increase in T1-signal intensity, that is, the lesion appears brighter than in precontrast images
b) Gadolinium results in T1 shortening of the tissue in which it accumulates resulting in a decrease in T1-signal intensity, that is, the lesion appears darker than in precontrast images.
c) Gadolinium is not used as an MR contrast-medium agent. It fluoresces in response to radiation and is used in the manufacture of radiographic intensifying screens.
d) Gadolinium is a commonly used MR contrast-medium agent. In addition, gadolinium fluoresces in response to radiation and is used in the manufacture of radiographic intensifying screens and some digital flat panels.

Answer 1

A and D

Question 2

3) Agenesis or rupture of the septum pellucidum…(which answers are false)
a) Is common in border collies with seizures
b) Is typically asymptomatic
c) Is seen in larger brachycephalic breeds
d) Is seen more commonly in older dogs

Answer 2

A and D

Question 3

4) Match the term with the definition

Answer 3

see image

lissencephaly- Lhasa apsos overrepresented

Question 4

5) What electrolyte abnormality do dogs with developmental abnormalities of the corpus callosum commonly have?
a) Hyponatraemia
b) Hypernataemia
c) Hyperchloraemia
d) Hyperkalaemia

Answer 4

B

Question 5

6) Which statement about intracranial epidermoid or dermoid cysts is incorrect?
a) They are commonly located in the fourth ventricle or cerebellopontine angle
b) They occur due to abnormal separation of the neuroectoderm from the ectoderm during development
c) They are common in Chinese crested dogs
d) They do not null in FLAIR sequences

Answer 5

C

Question 6

7) What is the significance of the structure the large arrow is pointing towards?
a) This is a dorsal atlantoaxial band, the presence is associated with the severity and clinical signs of syringomyelia is Cavalier king Charles spaniels
b) This is a sign of atlantoaxial luxation
c) This is a sign of atlantoaxial instability seen in cats with hyperflexion

Answer 6

A

Question 7

8) Hepatic insufficiency, particularly due to PSS, can lead to t1 hyperintensity of what area of the brain?
a) Brain stem
b) Lateral geniculate nuclei
c) Olfactory bulb
d) Lentiform nuclei

Answer 7

D

Question 8

9) What is you diagnosis in this 7 month old cat?
a) Toxoplasma
b) FIP
c) Bacterial meningitis
d) Cryptococcosis

Answer 8

B
usually causes ependymitis, resulting in marked contrast enhancement of the lining of the ventricular system

Question 9

10) What is the predictive value of a dural tail sign for a meningioma?
a) 10%
b) 55%
c) 88%
d) 94%

Answer 9

D

Question 10

11) Choroid plexus tumours commonly occur where? (more than one may be correct)
a) Lateral ventricles
b) Third ventricle
c) Fourth ventricle
d) Quadrigeminal cistern

Answer 10

b and c

Question 11

12) Which statement is false regarding pituitary tumours?
a) Tumours less than 5mm may not be visible with mri
b) They usually have minimal perilesional oedema
c) They strongly contrast enhance
d) Cystic regions and regions of haemorrhage can be seen

Answer 11

a. if less than 3mm they may not be seen

Question 12

13) Which cranial nerve is most likely to develop a nerve sheath tumour?
a) II
b) V
c) VII
d) VIII

Answer 12

B.

Although schwannoma, neurilemmoma, and neurofibroma are used interchangeably, the designation malignant (peripheral or cranial) nerve sheath tumor is recommended, because many of these tumors are malignant and determining the cell of origin (Schwann cell, perineurial cell, fibroblast, etc.) is not possible

Question 13

14) Which imaging characteristics would haemorrhage that occurred approximately 1 week ago (assume extracellular methaemoglobin) likely to have?
a) Hypointense on both T1- and T2-weighted sequences
b) Hyperintense on T1-weighted and hypointense on T2-weighted sequences
c) Hyperintense on both T1- and T2-weighted sequences.
d) Hypointense on T1-weighted and hyperintense on T2-weighted sequences

Answer 13

C

Question 14

15) A signal void in a GRE sequence can be caused by…
a) Haemorrhage
b) Mineralization
c) Gas
d) All of the above

Answer 14

D

Question 15

16) in what locations are basal and plaque-like meningiomas common?
a) Optic chiasm
b) Suprasellar region
c) Dorsal to the cerebellum
d) Cerebello-pontomedullary region

Answer 15

A and B

Question 16

17) How old is an infarct before it typically can show contrast enhancement on MRI?
a) Any time
b) After 1 day
c) After 3 days
d) After 1 week

Answer 16

C

it may also develop mass effect at this time

Question 17

18) How old can an infarct be before DWI sequences are less likely to be useful in differentiating it from other differentials (glioma, gme, encephalitis)?
a) 1 day
b) 3-5 days
c) More than 1 week
d) 10 days

Answer 17

B

Question 18

which type of supracollicular fluid accumulation is this?

Answer 18

type 2.
In the first pattern, there is enlargement of the caudodorsal recess of the third ventricle with the thin membrane separating the third ventricle from the quadrigeminal cistern being displaced caudodorsally. In pattern 2, there is enlargement of both the caudodorsal aspect of the third ventricle and the quadrigeminal cistern and the membrane separating these compartments is visible. In pattern 3, due to enlargement of the quadrigeminal cistern alone, the membrane separating the quadrigeminal cistern and the third ventricle is displaced rostrally. Enlargement of the quadrigeminal cistern results in varying degrees of flattening of the rostrodorsal aspect of the cerebellum

Question 19

craniopharygiomas occur where?
a) in the pharynx
b) near the sella turcica
c) in the cerebromedullarypontine angle
d) in the fourth ventricle

Answer 19

B
occur in the region of the sella turcica and are typically associated with anomalous development of the pituitary gland.
occur in the region of the sella turcica and are typically associated with anomalous development of the pituitary gland.

Question 20

which of the following is a common feature found with lobar holoprosencephaly in dogs?
a) agenesis of the optic chiasm
b) agenesis of the caudate nucleus
c) agenesis of the pineal gland
d) agenesis of the corpus callosum

Answer 20

D agenesis or dysgenesis
Holoprosencephaly is the failure of the forebrain to bifurcate normally into two discrete cerebral hemispheres. Holoprosencephaly exists in three forms, lobar form is most common in dogs.
miniatures schnauzers over-represented.

Question 21

name the 4 most common storage diseases of the brain according to thrall

Answer 21

Mucopolysaccharidosis, neuronal cell lipofuscinosis, cerebellar abiotrophy, and globoid cell leukodystrophy are the most common

Question 22

which description best describes juvenile NCL?
a) progressive juvenile cortical atrophy and hydrocephalus and an abnormally small corpus callosum
b) juvenile cortical atrophy and severe peripheral meningeal thickening and enhancement
c) progressive cerebellar atrophy
d) symmetrical white matter disease, mild hydrocephalus, and symmetrical contrast enhancement of the corpus callosum, internal capsule, and corona radiata.

Answer 22

B and A
Juvenile and adult onset disease seen. Brain atrophy, small corpus callosum.
Less common: Sometimes reduced GM/WM distinction with thinning of the GM. Meningeal thickening and enhancement
subdural haematoma in one dog

A- also mucopolysaccharidosis
C- cerebellar abiotropy
D- GCL

Question 23

which breed is over-represented idiopathic hypertrophic pachymeningitis?
a) border terrier
b) chinese crested
c) greyhound
d) GSD

Answer 23

C

Question 24

In dogs with neurological signs, what percentage of MRIs are normal in dogs with evidence of inflammatory disease from CSF analysis?
a) 90%
b) 53%
c) 8.3%
d) 24%

Answer 24

D

Question 25

what percentage of dogs with pituitary dependent hyperadrenocorticism, without neurological signs, have a pituitary tumour of 4-12mm in vertical height? a) up to 20% b) up to 40% c) up to 60% d) up to 90%

Answer 25

C. MR is useful for visualizing the presence of both microtumors (3–10 mm in diameter) and macrotumors (>10 mm) in dogs with PDH, with or without neurologic signs, especially when endocrine test results are equivocal. Pituitary tumors are always better visualized after contrast medium administration

Question 26

gliomatosis cerebri can mimic which other diseases?

Answer 26

Encephalitis, leukodystrophies, and metabolic encephalopathies. It is classified as a malignant (grade III) neuroepithelial tumor of astrocytic origin.

Question 27

meningioma or lymphoma?

Answer 27

There is thickening of both the peripheral meninges (particularly on the left, arrow) and the falx (rostrally). Mass lesions and meningeal infiltration are common manifestations of intracranial lymphoma in both cats and dogs. also consider histiocytic sarcoma.

Question 28

which of these is most likely to cross the cribriform plate a) olfactory neuroblastoma b) glioma c) glioblastoma multiforme d) meningioma

Answer 28

A or nasal masses/ fungal infection

Question 29

which vessels supply this infacrted region? (T2W, FLAIR, DWI, ADC) a) rostral cerebral b) caudal cerebral c) perforating arteries d) striate arteries

Answer 29

D

Question 30

name 3 T1W hyperintense substances/ tissues?

Answer 30

My Best Friend is Pretty Cool: M: melanin B: blood (i.e. methaemoglobin in subacute haemorrhage) F: fat and slow flow P: protein; paramagnetic substances (e.g. manganese, copper); posterior pituitary gland C: contrast (i.e. gadolinium) and cholesterol 3 Fs and 4 Ms: F: fat F: slow flow F: proteinaceous fluid M: melanin M: methaemoglobin M: mineralisation M: Magnevist (gadolinium contrast) plasma cell tumours (sometimes

Question 31

the average hounsfield units of haemorrhage is... a) 40-60HU b) 60-100HU c) 100-140HU d) 140-160HU

Answer 31

B

Question 32

in dogs, the T2w FLAIR mismatch sign is strongly correlated with... a) astrocytomas b) gliomas c) oligodenrogliomas d) ependymomas

Answer 32

C- usually low grade. The T2FMM was identified in 14/186 (8%) of MRI studies, and all dogs with T2FMM had oligodendrogliomas (n = 12 low-grade [LGO], n = 2 high-grade [HGO]; P < .001).