Radiology Of The Canine And Feline Skull 2

sihirlifil's version from 2017-11-02 22:54


Question Answer
Parts of the toothCrown, neck, root, pulp cavity
Lamina dura, alveolar bone
Periodontal membrane
Dog dental formula(I3/3 C1/1 PM4/4 M2/3)x2 = 42
Cat dental formulaa(I3/3 C1/1 PM3/2 M1/1)x2 = 30
Carnassial teeth =Maxillary PM4 & Mandibular M1
Red arrows? Blue? What view is this?
Red = PM 1-4
Blue = M 1 & 2
Maxillary oblique open mouth
Red arrows? Green? Which view?
Red = PM 1-4
Green = M 1-3
Mandibular open mouth view
Dentin of the tooth is covered by ___ at the crown and ___ at the rootEnamel at crown, cementum at root
What is this image showing?
Pulp cavity is radiolucent and large in young animals and gets smaller with age
Top = young
Bottom = older
Hypodontia/oligodontia =Missing teeth
Supranumerous teeth =Retained temporary teeth (pseudoplyodontia) or congenital polydontia
How can the crown change in shape?Fracture, abnormal wear, crown removed
How can the root change in shape?Periodontal disease
Displacement/deformation by adjacent mass
Lysis due to adjacent malignant tumor
Change in opacity: lucency, fracture, caries, wide pulp cavity = ?Young or dead tooth
Change in opacity: thinning of dentine layer = ?Dentinogenesis imperfecta
Radiographic changes of periodontal disease/tooth root infectionDestruction of alveolar bone & resorption of alveolar crest between adjacent teeth
Widening of periodontal space (vertical resportion)
Radiolucent halo around tooth root (periapical infxn/inflam --> abscess)
Loss of lamina dura due to widening/destruction
Sclerosis of alveolar bone surrounding lytic lesion
** = ? Arrow?
** = Sclerosis of surrounding alveolar bone
arrow = Lysis around roots
Also Widening of periodontal space and loss of lamina dura
Feline Odontoclastic Resorptive Lesion (FORL) aka?Neck lesions, cervical line erosion, feline caries, feline cavity
FORL: what's going on?Teeth progressively resorbed by odontoclasts, beginning at gingival border
Resorbed cementum and dentin replaced by bone-like tissue
What can happen with extensive feline tooth root abscesses?Formation of fistulous tract exiting near the medial canthus of the eye
Arrows pointing to?
(Feline tooth root abscess) Lysis around root of canine tooth, wide pulp cavity, gas inclusions in the soft tissue

Nasal Disease

Question Answer
Rhinitis: non-destructiveBacterial rhinitis
FB rhinitis (small or recent)
Rhinitis: destructiveFungal rhinitis (aspergillus etc)
Nasal neoplasia
Chronic FB rhinitis
Long-standing chronic rhinitis
Recommended radiographic viewsLateral
Open-mouth VD
Intraoral DV
Rostrocaudal frontal sinus projection (non-brachycephalic)
Which modality is best? why?CT!
Shows each structure without superimposition, can consistently ID subtle destruction & potential penetration towards the brain
Blue? Yellow? Orange? (VD open mouth maxilla)
Blue = nasal & ethmoid turbinates (symmetrical, filamentous pattern)
Yellow = bony nasal septum
Orange = cribriform plate
Can also see Maxillary bone, teeth & alveolar bone
L & R nasal cavities separated by ___Boney nasal septum
Normal skull shows symmetry!
How does bacterial rhinitis look on radiographs?Nares +/- occluded
Can be uni or bilateral
Can ID septum
Increase in soft tissue/fluid opacity superimposed on bony turbinate pattern
Turbinates hard to ID but visible, may be thickened
Bacterial rhinitis (open mouth VD projection)
Bilateral increased ST opacity, preserved bony turbinate detail, nasal septum intact (next dx steps: do flush, figure out what's in there)
How does fungal rhinitis look on radiographs?Abnormal nares, asymmetrical pattern
Uni or bilateral, usually mesati- or dolichocephalic breeds
Septum intact
Patchy hollow turbinate pattern (destruction) superimposed with increased soft tissue opacity, parts of nasal cavity appear empty
Frontal sinus often involved: ST opacity, thickened frontal bone
+/- periosteal reaction
Focal (punctate) lysis of nasal/frontal/maillary bone in advanced cases
Fungal rhinitis (open mouth VD projection)
Predominantly right sided changes
How do nasal tumors look on radiographs?Increased opacity of nasal cavities (mass/fluid)
Turbinate pattern assymetrical & LYSIS
Septum deviated +/- destroyed
Mass effect +/- expansion into contralateral nasal cavity
Soft tissue swelling on maxilla
Reactive new bone
+/- Destruction/deformation of adjacent nasal, maxillary, ethmoid, frontal bone
+/- Invasion of frontal sinus
+/- missing teeth
Nasal tumor (open mouth VD)
Primary lesion in left nasal cavity
What's happening with these rads?
Initial & follow-up radiographs showing progression of a nasal tumor
Initial: increased ST opacity in L nasal cavity, turbinate pattern still visible
Follow-up: ST mass occupies entire L cavity, bony detail gone
Most common nasal tumor in dogsCarcinoma
Others: sarcoma, chondrosarcoma
Less common in brachcephalic dogs (for a change)
Most common nasal tumor in catsNasal lymphoma (may be associated with renal lymphoma)
Cat with mainly left-sided nasal destructive mass (DV intraoral projection)
Abnormal appearance of bony nasal septum
Optimal modality to investigate nasal diseaseCT!!!
CT of nasal tumor (Transverse images, ST window)
Displacing, invading, destroying the normal nasal tissues


Question Answer
Line pointing at
External acoustic meatus
What does otitis media look like on radiographs?Thickening & increased opacity of tympanic bulla
Otitis media L side (Rostrocaudal open mouth projection)
White arrow = Odontoid peg
What's happening in these radiographs? Arrow? *?
Nasopharyngeal polyp & otitis media in a cat
Arrow = ST mass protruding into pharynx
* = increased opacity & thickening of R tympanic bulla
Bony changes indicate a chronic lesion
Optimal modality for ear diseaseCT again! (good for external ear canal and middle ear)
What are these CT projections showing?
Left: normal
Middle: Otitis media
Ceruminous gland adenocarcinoma
Benign ear canal tumors (9)Polyp
Sebaceous gland adenoma
Ceruminous gland adenoma
Basal cell tumor
Benign melanoma
Malignant ear canal tumors (8)Ceruminous gland adenoCARCINOoma
Squamous cell carcinoma
Carcinoma (undetermined origin)
Sebaceous gland adenoCARCINOma
Round cell tumor
Malignant melanoma
Which tumor type more common in cats?Malignant :(
What does ceruminous gland adenoCA look like on radiographs?Soft tissue mass w/ destruction of tympanic bulla
Ceruminous gland adenocarcinoma

Skull Fractures

Question Answer
Which skull bones can fracture?Any (cranium, maxilla, mandible, involving TMJ)
Big problem when radiographing skull fractures?Superimposition
Refer for CT!
Productive benign osseous lesions (6)CMO (Craniomandibular osteopathy in WHWT) (west highland white terriers?)
Hyperostosis of the calvarium in young Bull mastiffs (unknown pathogenesis, self-limiting)
Productive osteomyelitis
Healing fracture
Acromegaly in cats (enlarged skull & mandible)
Hypervitaminosis A in cats (occipital new bone)
Craniomandibular osteopathy: progressive? what's it look like?SELF-LIMITING in young dogs
Bilaterally symmetrical!
CMO of the tympanic bulla, calvarium
CMO of the mandible
Top ddx of CMO?Mandibular osteomyelitis
How do you tell CMO & mandibular osteomyelitis apart?Both are highly proliferative periosteal bone production, but mandibular osteomyelitis is UNILATERAL
Mandibular osteomyelitis
How do malignant neoplasias look?Proliferative or osteolytic (geographic to permeative)
Teeth may be displaced, eroded, or lost
Radiographs do not help predict histologic nature of lesion
Most common oral tumor in DOGSMalignant melanoma
Most common oral tumor in CATSSCC
List malignant oral tumorsSCC (cats)
Malignant melanoma (dogs)
Primary bone tumor (OsteoSA)
Other oral sarcomas
How do non-malignant tumors behave?Highly invasive & destructive odontogenic tumors
List non-malignant oral tumorsAcanthomatous ameloblastoma (mostly in dogs) (aka acanthomatous epulis, basal cell CA, adamantinoma)
Complex & compound odontoma (dental opacities)
These are radiographs of what?
SCC (in an 11-y-o male golden retriever... weird)
Soft tissue into bone
Ameloblastic odontoma aka?Epulides, acanthomatous, Adamantinoma
Ameloblastic odontoma: how does it behave? Originates?Benign but aggressive (frequently invades bone)
Originates from periodontal ligament
More common in DOGS than cats
Ameloblastic odontoma: how to tx?Sx removal, radiotherapy, bleomycin tx
May recur :(
Ameloblastic odontoma in a dog
This is a CT transverse image, bone window, at the level of the TMJs. What disease?
Neoplasia affecting articular process of the TMJ
Complication of meningioma in cats?Hyperostosis in bone adjacent to tumor
Examples of multilobular tumors of boneOsteochondroma rodens
Multilobular osteochondroSA
How common are multilobular tumors of bone? Occur where?Uncommon
Calvarium, maxilla, & mandible
Multilobular tumors of bone: what happens?Lysis AND proliferation!
Slow growing
Recurrance after removal & metastasis are reported
(Other neoplasia with bone proliferation of skull)(Osteoma)
What are these three animals (dog/cat/dog) affected with? (CT transverse bone)
Multilobular tumor e.g. chondoma rodens, multilobular osteochondroSA
May present with neuro signs
Foreign body!
These 2 radiographs demonstrate the importance of what concept?
Left is in pharynx, right in nasal passage! Can't always tell the difference with only VD/DV view!

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