Upper Airway Imaging

Question 1

what makes up the upper airway

Answer 1

nasal cavity
pharynx
larynx
trachea
mainstem bronchi

Question 2

what views are used to image the nasal cavity

Answer 2

DV
open mouth VD
intraoral DV
lateral
frontal (rostrocaudal)

Question 3

what is viewed on standard DV imaging of the nasal cavity

Answer 3

nasal passages (has summation of mandible)

look for symmetry

Question 4

what is viewed on open mouth VD imaging of the nasal cavity

Answer 4

maxilla, nasal septum, and nasal passages without summation of mandible

should see fine lined turbinates within the nasal passage

Question 5

what is viewed on intraoral DV imaging of the nasal cavity

Answer 5

similar to open mouth VD but with a plate inside the mouth - image does not extend as far caudally

Question 6

what is viewed on lateral imaging of the nasal cavity

Answer 6

frontal sinuses and bony structures (has summation of nasal passages)

may need wedge/spoon to keep face parallel to plate

Question 7

what is viewed on frontal imaging of the nasal cavity

Answer 7

frontal sinuses - gas filled

summation excludes the nose from view

Question 8

what factors do you evaluate on nasal radiographs

Answer 8

1. nasal passage opacity
2. turbinates
3. frontal sinus opacity
4. bone integrity (septum, frontal, maxillary)

Question 9

hyperplastic rhinitis

Answer 9

• increased ST opacity in nasal passage
• loss of turbinate detail
• sinuses unaffected

usually BILATERAL

Question 10

ddx for hyperplastic rhinitis

Answer 10

• infectious - viral or bacterial
• allergic/autoimmune
• foreign body
• dental disease
• hemorrhage

Question 11

destructive rhinitis

Answer 11

• destruction of turbinates
• lucent areas in nasal passage
• focal areas of increased ST opacity
• frontal sinus plaques (“cotton ball” plaques in sinuses from fungal rhinitis)

Question 12

ddx for destructive rhinitis

Answer 12

• chronic fungal rhinitis (dogs - aspergillus; cats - cryptococcus)
• chronic foreign body rhinitis
• severe lymphoplasmacytic rhinitis

Question 13

nasal neoplasia

Answer 13

• ST mass
• turbinate destruction
• bony distortion/destruction
• facial swelling

usually UNILATERAL

Question 14

ddx for nasal neoplasia

Answer 14

carcinoma (dogs)
lymphoma (cats)

Question 15

what view is most often used to evaluate larynx and pharynx

Answer 15

lateral

Question 16

what are normal radiographic changes in the larynx and pharynx

Answer 16

old dogs get mineralization of tracheal rings, epiglottis, and laryngeal cartilage

Question 17

what are most common radiographic pathologies of the pharynx

Answer 17

1. elongated/thickened soft palate
2. foreign bodies
   - ST swelling and tracheal displacement
3. trauma
4. masses (neoplastic, polyps, lymphadenopathy, abscess)
   - masses: displacement of soft palate, secondary gas in pharynx
   - LNs: narrowing of pharynx, increased sT opacity pushing on dorsal pharyngeal wall

Question 18

what are radiographic pathologies of the larynx

Answer 18

1. edema/inflammation
   - thickening of larynx
   - increased opacity in area of larynx
2. neoplasia
   - destruction of hyoid apparatus
   - ST opacities
3. upper airway obstruction
   - larynx and hyoid pulled caudally
   - gas dilation of pharynx
   - dogs: under-inflated chest
   - cats: over-inflated chest

Question 19

what views are used to evaluate the trachea

Answer 19

lateral
DV

Question 20

normal trachea on lateral projection

Answer 20

diameter should be slightly smaller than the larynx

can get normal deviations with flexion/extension of the neck

Question 21

normal trachea on DV projection

Answer 21

should run just to the right of the heart with constant diameter

Question 22

pathologies causing tracheal deviation

Answer 22

1. cranial mediastinal mass
   - trachea deviates right w/ compressed lumen
2. hilar lymphadenopathy
   - caudal trachea deviates ventrally
3. left atrial enlargement
   - caudal trachea deviates dorsally
4. persistent R aortic arch
   - trachea deviates ventrally and to the left

Question 23

pathologies causing tracheal narrowing

Answer 23

1. hypoplasia
   - congenital malformation causing trachea to be 1/2 size of the larynx
2. collapse
   - degeneration of tracheal cartilage; narrowing varies on inspiration/expiration
3. masses
   - neoplasia uncommon
4. trauma
   - pneumomediastinum and subcutaneous emphysema