CT Flashcards

1
Q

What are the dental formulas for dogs & cats?

A

Dog 42 (I 4/4, C 1/1, P 4/4, M 2/3)
Cat 30 (I 4/4, C1/1, P 3/2, M 1/1)

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2
Q

Which neoplasia of the mandible/maxilla tends to be more osteoproliferative than others?

A

Chondrosarcoma

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3
Q

What is the most common tumor of the soft palate?

A

Lymphoma

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4
Q

What is the most common tonsillar and lingual neoplasia in dogs?

A

Squamous cell carcinoma

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5
Q

Where are dentigerous cysts most commonly seen?

A

Near 1st premolar in brachycephalic dogs

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6
Q

What is the difference in origin between an epulide and an odontogenic tumor?

A
  • Epulides arise from periodontal ligament (benign gingivial proliferation)
  • Odontogenic tumors arise from dental lamina (rare)
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7
Q

What is the hallmark feature of an odontoma?

A

Dental structures within the mass

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8
Q

What foramen is at the level of the TMJ joints? What structure(a) pass through it?

A

Oval foramen
- mandibular branch of trigeminal nerve

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9
Q

What are the 5 muscles of mastication?

A

1) Temporal (innervation: mandibular n)
2) Masseter (mandibular nerve)
3) Medial pterygoid (mandibular N)
4) Lateral pterygoid (mandibular N)
5) Dogastricus ( mandibular & facial nerves)

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10
Q

What is the pathophys of jaw drop? And what conditions cause it?

A

Jaw drop requires bilateral flaccid mandibular nerve paralysis.
-Etiologic conditions = idiopathic trigeminal neuropathy, lymphoma, juvenile masticatory myositis; rare differentials = rabies, botulism, Meningiomas

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11
Q

Why is the digastricus muscle unaffected by masticatory myositis?

A

Made of type 2A fibers. Masticatory myositis affects 2M fibers

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12
Q

What dog breed is predisposed to juvenile masticatory myositis?

A

Cavies

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13
Q

What 6 bones form the orbit?

A

1) Frontal
2) Lacrimal
3) Zygomatic
4) Palatine
5) Maxillary
6) Sphenoid

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14
Q

What structures pass through the orbital fissure?

A

Oculomotor, trochlear, abducens, and ophthalmic branch of trigeminal nerve, anastomotic branch of external ophthalmic artery, & orbital venous plexus

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15
Q

What is different about the feline osseous orbit?

A

Bony floor consists of only a small part of maxillary bone holding the last molar teeth

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16
Q

What 3 dog breeds are predisposed to extraocular polymyositis?

A

Goldens
Springer Spaniels
Dobermans

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17
Q

What are 3 common optic nerve tumors?

A

Neurofibrosarcoma
Glioma
Meningioma

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18
Q

What breed(s) are typically affected by craniomandibular osteopathy & calvarial hyperostosis respectively? And how can you differentiate the two conditions?

A

Craniomandibular osteopathy - Westies, Dobies, Labs, Bullmastiffs ; affects mandible, tympanic bulls, calvarium, & petrous temporal bone

Calvarial hyperostosis- bullmastiffs; affects calvarium (frontal, parietal, occipital) WITHOUT mandible abnormalities

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19
Q

MLO of the skull has a predilection site where?

A

Calvarium & zygomatic arch

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20
Q

What are the first and second most common primary bone tumors of the skull?

A

1) Osteosarcoma
2) Chondrosarcoma

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21
Q

Where is the lateral retropharyngeal lymph node located and in what percentage of dogs & cats is it present in?

A

Between the ear base & wing of C1
-Present in ~ 30% of dogs & almost always in cats

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22
Q

Where are the superficial cervical lymph nodes located?

A

Usually paired & located cranial to supraspinatus in between neck musculature

23
Q

Where are the deep cervical nodes located & in what percentage of dogs & cats are they present in?

A

Located cranial to the thyroid gland
- present in ~ 30% of dogs & ABSENT in cats

24
Q

Where does the auditory tube enter the nasopharynx?

A

Dorsolaterally just caudal to the pterygoid hamulus process

25
Q

What is displaced with caudal transtentorial herniation?

A

Displacement of portions of cerebral cortex/cortices VENTRAL to tentorium cerebelli

26
Q

What 2 areas of the brain are particularly affected by necrosis secondary to seizures?

A

Hippocampus & piriform loves

27
Q

What are the two key components of Dandy-Walker syndrome?

A

Partial or complete absence of cerebellar vermis &cystic dilation of the 4th ventricle

28
Q

Dry form of FIP results in what lesions?

A

Pyogranulomatous inflammation of the Leptomeninges, choroid plexus, ependyma & brain parenchyma

29
Q

What dog breed is predisposed to necrotizing leukocephalitis & what location(s) does it affect?

A

Adult Yorkshire Terrier
- cerebrum & brainstem

30
Q

What pituitary lesion has a stalk-like appearance?

A

Craniopharyngioma

31
Q

Where does the maxillary branch of the trigeminal nerve exit in cats?

A

Round foramen (there is no alar canal in cats)

32
Q

Where does the maxillary branch of the trigeminal nerve exit in dogs?

A

Round foramen —> alar canal —> rostral alar foramen

33
Q

What congenital abnormality can result in reduced tracheal diameter with thickened misshapen cartilages?

A

Mucopolysaccardosis 7

34
Q

What are the 3 reflections of the mediastinum?

A

1) Cranioventral
2) Caudoventral
3) Plicae vena cava

35
Q

Describe the course of the mediastinum and what obliques it cranially & caudally, respectively?

A

Runs obliquely craniocaudally from right to left.
- Ventral cranial mediastinum slightly to RIGHT due to left cranial lung extension across midline
- Caudal mediastinum is to LEFT of midline due to extension of accessory lung lobe

36
Q

Where is the Cisterna chyli located and what originates from it?

A

Cisterna chyli originates ventral to L4.
-thoracic duct originates from the Cisterna chyli

37
Q

What is the course of the thoracic duct in the thorax?

A

Runs dorsal to aorta & ventral to azygous vein.

38
Q

Describe a possible appearance of the cisterna chyli….

A

Sometimes seen as a “ hat-shaped” structure draping dorsally over aorta

39
Q

Mean density levels for lung CT in dogs during expiration and inspiration are what?

A

-713 Hu = expiration
-846 Hu = inflated inspiration

40
Q

What lung lobes are most likely to torse in deep-chested and barrel-chested breeds respectively?

A

Deep-chested: right middle
Barrel-chested: left cranial

41
Q

Lower attenuation values have reported in the liver and spleen with what conditions, respectively?

A

Liver: hepatic lipidosis (cats/tortoises)
Spleen: hemangiosarcoma (in relation to benign etiologies such as hematomas & focal nodular hyperplasia)

42
Q

What cat breed commonly develops pancreatic cysts?

A

Persians

43
Q

What are the CT features of acute pancreatitis?

A

-Enlargement or mass effect
- Hypodense central or peripheral areas
- LACK of contrast enhancement
- Ascites
- Regional thrombosis possible

44
Q

Where is the Cisterna chyli located?

A

Ventral to the first 4 lumbar vertebrae.
- Bordered ventrally by aorta & dorsally by azygous vein
-Becomes thoracic duct as it passes through aortic hiatus

45
Q

What are the CT characteristics of an ameloblastoma?

A

-Mandibula > maxilla
- locally destructive
- spherical or multilocular cystic
- expansile

46
Q

What are the CT characteristics of an odontoma?

A

-lobulated enamel foci within a well-defined cyst like structure
- at root of maxillary tooth

47
Q

In horses, the dorsal and ventral nasal conchae divide the nasal cavity into what?

A

Longitudinally into the dorsal, middle, and large ventral nasal meatus

48
Q

What are the communications and separations between the frontal and maxillary sinuses?

A
  • sinuses communicate with eachother via large oval opening
  • direct communication with nasal cavity
  • separated into rostral and caudal parts by thin bony septum
    -separated into medial & lateral compartments by infra orbital canal
49
Q

The rostral and caudal maxillary sinuses overlie the apices of which teeth , respectively?

A

Rostral maxillary sinus - Triadan 8 & 9

Caudal maxillary sinus - Triadan 10 & 11

50
Q

The dorsal and ventral conchal sinuses communicate with what structures respectively?

A

Dorsal conchae - caudal maxillary sinus

Ventral conchae - rostral maxillary sinus

51
Q

What is the etiology of a dentigerous cyst?

A

Incomplete closure of the 1st branchial cleft —> cyst like structure surrounding tooth crown (often adjacent to temporal bone)

52
Q

Describe the CT features of cholesterinic granulomas in horses?

A
  • Benign outgrowths of choroid plexus
  • common & often bilateral
  • occur in lateral and 4th ventricles
  • can cause neuro signs due to obstructive hydrocephalus or direct brain compression
53
Q

What structures are collectively termed the distal sesamoidean ligaments?

A
  • short sesamoidean ligament
    -oblique sesamoidean ligament
  • cruciate sesamoidean ligament
    -straight sesamoidean ligament