More brain Flashcards
(98 cards)
What are imaging characteristics of a mucocele?
Imaging diagnosis - IC mucocele in a dog. VRU 49.6
Similar to an abscess
T2/FLAIR hyperintense
T1 - isointense
Peripheral ring enhancement
Abscesses generally have more perilesional edema, cystic core
Why do mucoceles form?
Imaging diagnosis - IC mucocele in a dog. VRU 49.6
buildup of mucus secretions with cyst formation
Occur secondary to occlusion of nasofrontal duct caused by inflammation, fibrosis, trauma, congenital abnormality or neoplasia
What is an empty sella? how was it graded?
MRI features of empty sella in dogs. VRU 49.4
Absent or reduced pitutiary siz.
Hypophyseal tissue filling more than 50% of the sella - normal
30-50% - partial empty sella
In humans, what clinical symptoms correspond with empty sella syndrome?
Do dogs have similar symptoms?
MRI features of empty sella in dogs. VRU 49.4
pituitary insufficiency, hypertension, headache, CSF leakage (hydrocephalus), increased, benign intracranial pressure
Dogs did not have similar symptoms or evidence of pituitary insufficiency
What are the different forms of empty sella syndrome?
MRI features of empty sella in dogs. VRU 49.4
Primary - incomplete formation
Secondary - adenoma with necrosis, infarction, infection, autoimmune disease, iatrogenic
Is there an association with empty sella syndrome and ventriculomegaly?
MRI features of empty sella in dogs. VRU 49.4
No.
How is normal ventricle size measured via US or MRI?
Is there clinical signs associated with degree of ventriculomegaly?
MRI features of empty sella in dogs. VRU 49.4
US imaging of the lateral cerebral ventricles in dogs VRU 31.2
Ratio between ventricular height and height of brain
25% - severe ventriculomegaly
No association between ventriculomegaly and clinical signs.
What is the normal width and height of a dog pituitary gland?
Is there association between body weight, brain size and pituitary size?
Mensuration of normal pituitary gland from MRI in 96 dogs. VRU 42.2.
5mm height
6.5mm width
No association between pituitary size, body weight, brain volume/size.
What is normal width, height and length of a cat pituitary gland?
What is normal volume?
Is there significance between age, body weight, and pituitary size?
Mensuration of normal pituitary gland from MRI in 17 cats. VRU
Width: 5mm
Height: 3.4mm
Length: 5.5mm
Volume: 0.05cm^3
No association
What percentage of cats will have multiple meningiomas?
Imaging diagnosis - synchronous primary brain tumors in a dog VRU 48.6
17%
What are primitive neuroectodermal tumors?
Imaging diagnosis - synchronous primary brain tumors in a dog VRU 48.6
Another term for medulloblastoma
What is Dandy-walker malformation?
Imaging diagnosis - dandy walker malformation VRU 49.3
Congenital malformation of the CNS - most notably the cerebellum and adjacent tissues
What characteristics do most Dandy-walker malformations have?
Imaging diagnosis - dandy walker malformation VRU 49.3
Absent/small cerebellar vermis
Cystic malformation of the fourth ventricle
Enlargement of the posterior fossa
Other variants: cystic malformation of 4th ventricle without enlargement of posterior fossa, enlargement of cisterna magna with compression/atrophy of cerebellum
What is the triad of findings associated with Dandy-Walker Syndrome?
US appearance of Dandy-walker-like syndrome in a boston terrier. VRU 45.4
Hydrocephalus
Vermian hypoplasia
Cysts associated with the fourth ventricle
What breed may be predisposed to Dandy-walker syndrome?
Boston terriers
US appearance of Dandy-walker-like syndrome in a Boston terrier. VRU 45.4
What is characteristic signalment/history of feline hippocampal necrosis?
MRI of feline hippocampal necrosis VRU 49.4
Animals of any age
Cats from switzerland or italy
Generalized/complex seizures
What is appearance of hippocampal necrosis on MRI in felines?
MRI of feline hippocampal necrosis VRU 49.4
Hippocampus and piriform lobe T2 hyperintense, T1 hypointense and various degrees of contrast enhancement
What are MRI characteristics of an epidermoid cyst?
Imaging diagnosis - IC epidermoid cyst in a Doberman pinscher - VRU 48.3
This is different from other article: Canine IC epidermoid cyst VRU 40.4
T2: hyperintense - similar to CSF FLAIR: hyperintense No edema T1 - hypointense T1 +C - +/- rim enhancement
Where do epidermoid cysts most commonly occur?
Imaging diagnosis - IC epidermoid cyst in a Doberman pinscher - VRU 48.3
cerebellopontine angle - 40-50%
4th ventricle - 15%
sellar fossa - 10-15%
What are imaging differences between epidermoid cysts vs dermoid cyst vs arachnoid cyst?
Imaging diagnosis - IC epidermoid cyst in a Doberman pinscher - VRU 48.3
Epidermoid cyst: T2: hyperintense - similar to CSF FLAIR: hyperintense No edema T1 - hypointense T1 +C - +/- rim enhancement
Dermoid cyst: Hyperintense in T1 and T2 due to high fat content
Arachnoid cyst: hypointense on FLAIR, similar to CSF.
Epidermoid cysts have higher signal on FLAIR due to protein/cholesterol content
What are imaging characteristics of a dermoid cyst within the medulla?
MRI of a medullary dermoid cyst with secondary hydrocephalus in a dog. VRU 40.1
T1 - dramatically hyperintense (pre-contrast)
T2 - hyperintense
**both T1 and T2 had patchy regions of low signal - likely due to presence of hair, sweat, glandular tissue
Post contrast - no enhancement
No edema
Why are dermoid cysts hyperintense on T1 weighted images?
MRI of a medullary dermoid cyst with secondary hydrocephalus in a dog. VRU 40.1
Presence of fat
What are reasons for hyperintense on pre contrast T1 images?
MRI of a medullary dermoid cyst with secondary hydrocephalus in a dog. VRU 40.1
Fat
Slow flowing blood
Melanin
Hemorrhage - early/late subacute phase - due to methemoglobin
How do you differentiate between pure fat lipomas and dermoid cysts?
MRI of a medullary dermoid cyst with secondary hydrocephalus in a dog. VRU 40.1
Lipomas are more uniform -will completely suppress with STIR images
Can be difficult if dermoids are highly fatty