Axial Skeleton Imaging

Front 1

*What are the 5-6 radiographic opacities?

Back 1

Metal> mineral> soft tissue/fluid > fat > gas
-Term is opacity

Front 2

**Positioning is critical with axial skeleton radiographs, so what should you do?

Back 2

Sedation or anesthesia!!!

Front 3

Opacity is to X-rays as _______ is to CT.

Back 3

Attenuation

Front 4

*What are the 5 attenuations of CT?

Back 4

Metal> mineral> soft tissue/fluid > fat > gas
-Same as X-rays, but its attenuation not opacity!

Front 5

Why are CT's so good for bony structures such as the spine?

Back 5

No superimpositing of structures because there's multiple imaging planes

Front 6

What are the disadvantages of CT's?

Back 6

Need special machine and someone who can interpret them-specialist

Front 7

*What imaging is the best determinant of lesion localization?

Back 7

MRIs
-Best technique or soft tissues too and neural structures!

Front 8

What do MRI's use instead of X-rays? What's the term used instead of opacity?

Back 8

Protons
Term is intensity

Front 9

How does bone appear on an MRI? Soft tissues?

Back 9

Hypo-intense=black!-bone
Soft tissues are shades of gray

Front 10

What is the spinal formula of the dogs? Cat?

Back 10

Dog: C7:T13:L7:S3:Ca20
Cat: C7:T13:L7:S3:Ca22-23

Front 11

**What are the 3 locations that have narrower disc spaces?

Back 11

1) C2-3
2) C7-T1
3) T10-T11 (anticlinal-spinous processes are upright)

Front 12

What region most commonly gets IVDD?

Back 12

Thoracolumbar junction

Front 13

The ventral margin of _____ is irregular.

Back 13

L4

Front 14

**Where does the diaphragm insert on the vertebral column?

Back 14

Ventral margin of L4

Front 15

Where on the vertebral column is spondylitis from a migrating grass awn most likely? Why?

Back 15

L4 because that's where the diaphragm inserts

Front 16

Where do the nerve roots exit the spinal cord?

Back 16

Intervertebral foramen

Front 17

Can you get osteoarthritis in the spine?

Back 17

Yes, the caudal articular process articulates with cranial articular process=joint

Front 18

Accessory processes _____-___ summate with the intervertebral foramen.

Back 18

T11-L6
-NOT herniated disk material!

Front 19

True or false. Mineralized discs usually cause spinal cord or nerve compression.

Back 19

False, not in the correct locations

Front 20

**When do discs mineralize in chondrodystrophic breeds?

Back 20

By 2 years of age
-so just bc have a mineralized disc doesn't mean its causing the pain!

Front 21

How can you tell if a disc is mineralized?

Back 21

Compare width of adjacent spaces

Front 22

**Where is contrast medium injected for a myelography?

Back 22

Subarachnoid space

Front 23

**What kind of contrast medium do you want to use for a myelography?

Back 23

Nonionic, iodinated contrast medium
*Kills patient if ionic bc sucks water into CSF

Front 24

What are the 3 layers of the meninges?

Back 24

1) Dura
2) Arachnoid
3) Pia
*Don't want to inject contrast medium into subdural space

Front 25

What are the 3 injection sites for contrast medium when performing a myelogram?

Back 25

1) L5-6
2) L4-5
3) Cisternal

Front 26

What are the 3 types of lesions that can occur in the spinal cord and can be seen by myelography?

Back 26

1) Extradural
2) Intradural-extramedullary
In the dura outside the spinal cord
3) Intramedullary
-in spinal cord

Front 27

**How does an extradural lesion appear on a myelogram?

Back 27

Deviation with thinning of the subarachnoid contrast medium columns on lateral projections

Front 28

**What type of lesion does IVDD cause (Intramedullary, intradural-extramedullary, extradural)?

Back 28

Extradural

Front 29

**How does an intradural-extramedullary lesion appear on a myelogram?

Back 29

-Filling defect within contrast medium column
-**Golf-tee sign

Front 30

**What neoplasia causes an intradural-extramedullary lesion?

Back 30

Meningioma

Front 31

***How do intramedullary lesions appear on a myelogram?

Back 31

Thinning/loss of contrast medium columns on lateral and VD/DV projections

Front 32

**What are 2 common causes of intramedullary lesions?

Back 32

1) Neoplasia
2) Edema

Front 33

**What are transitional vertebrae?

Back 33

Vertebrae takes on characteristics of neighboring section
-Usually incidental

Front 34

What is an example of a transitional vertebrae b/w the cervical and thoracic lumbar?

Back 34

C7 with ribs
-Takes on characteristics of T13

Front 35

What is an example of a transitional vertebrae at thoracic-lumbar vertebrae?

Back 35

T13 with no ribs
L1 w/ elongated transverse process

Front 36

What is an example of a transitional vertebrae at the lumbar-sacral area?

Back 36

-Fusion of transverse process with sacrum
-Sacrum w/ disc spaces
~Can be associated with cauda equine syndrome