Diagnostic imaging of lame horse Flashcards

1
Q

Intrathecal analgesia

A

Joints, bursae, tendon sheaths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Blocks are not

A

Lasers

-may need to image adjacent structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

If you can localize lameness

A

Bone scan
Neurologic
-Neuro exam
-Cranial and/or cervical imaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Radiography indications

A
  1. Lame
  2. Trauma
  3. Infection
  4. Screening
  5. Eval healing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Radiography pros

A
  1. Technically simple
  2. Inexpensive
  3. Portable
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Radiography cons

A
  1. Ionizing radiation
  2. Limited by anatomical thickness
  3. Limited contrast resolution: limited for soft tissue eval
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Portable machine settings

A

10-30 mA; 70-90 kVp

  • Skull
  • C spine
  • Up to stifle/shoulder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Marker always

A

Dorsal or

Lateral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Myelography indication

A

Spinal cord compression DDX

  • CVM (Wobblers)
  • Trauma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Arthrography/Bursography Indicationts

A
  1. Determine communication with a wound
  2. Eval adjacent structures
    - ligaments
    - joint capsule
    - tendons
    - cartilage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Fistulography indications

A
  1. Determine extent of wound and structures involved
  2. Look for source of draining tract
    - FB, sequestrum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Ultrasound indications

A
  1. Ush second diagnostic step after rads
  2. Suspected soft tissue injury
    - heat, swelling, pain on palpation tendons and ligaments
  3. Trauma
    - limited by SC gas, best with intact skin
  4. Guidance for intrathecal or intralesional injection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Ultrasound Pros

A
  1. Portable
  2. Relatively inexpensive
  3. No radiation
  4. Good soft tissue eval
  5. Great for serial eval-healing/progression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Ultrasound cons

A
  1. VERY user dependent
  2. Limited Osseous eval
  3. Limited depth of penetration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Ultrasound procedure

A
  1. Always image in two planes: long and transverse
  2. Contralateral limb for comparison
  3. Consistent labeling
    - Zones
    - Distance from point of hock or accessory carpal bone
    * Proximal to left, LF: lateral to left, RF: medial to left
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

High frequency transducer

A

best resolution, less penetration

17
Q

Low frequency transducer

A

deeper penetration but poorer resolution

18
Q

7-12 MHz probe

A

Penetrates 5-7 cm

19
Q

5 MHz probe

A

Penetrates about 12-14 cm

20
Q

2-3 MHz probe

A

Penetrates 20-30 cm

21
Q

Depth knob

A
  • Determines field of view

- Limited by frequency range of transducer

22
Q

Focal zone knob

A
  • Point of greatest resolution of sound beam

- Change every time you change depth

23
Q

Gain knob

A
  • Amplifies returning echoes

- TGC allows you to adjust gain by region

24
Q

Image interpretation

A
  1. Size
  2. Shape
  3. Echogenicity
  4. Margins
  5. Fiber pattern
25
Q

Hyperechoic

A

Bright

  • Scar tissue
  • Mineralization
26
Q

Hypoechoic

A

Dark

  • Fiber disruption
  • Diffuse edema vs core lesion
27
Q

Nuclear scintigraphy

A
Binds to osteoblast act
Vascular phase
Soft tissue phase
Bone phase
*Images displayed as if looking at the horse
*Sensitive, not specific
28
Q

Nuclear scintigraphy indications

A
  1. Subtle/multiple limb lameness
  2. Poor performance/unlocalized lameness
  3. Assess hard to access areas
  4. Whole body scan
  5. Assess tissue viability
29
Q

MRI indications

A
  1. Most complete eval-gold standard
  2. No abnormalities on rads or US
  3. Patient not responding to empirical tx
  4. Early intervention needed
    - confirmation septic arthritis/osteomyelitis
    - +/- IV contrast
30
Q

MRI Pros

A
  1. Gold standard for MSK
  2. Excellent soft tissue contrast resolution
    - great anatomical detail
  3. Sensitive for bone signal
    - bone edema/hemorrhage/necrosis
31
Q

MRI Cons

A
  1. Expensive
  2. Limited availability
  3. Extremely limited by anatomy
  4. General anesthesia
  5. Specific targeted exam
  6. Expertise req’d for interpretation
32
Q

MRI: the more detailed blocking pattern equals

A

More accurate MRI

33
Q

MRI High field (1-3T)

A
  1. Mild lameness/subtle injury suspected
  2. Joint dz is a major DDX
  3. Lameness localizes to proximal to foot
  4. Most amount of info
34
Q

MRI low field standing ( < 1 T)

A
  1. Anesthesia contraindicated, not worth it
  2. More severe injury suspected
  3. Lameness reliably located to foot
  4. Serial recheck exams
35
Q

CT indications

A
  1. Characterize osseous injury
  2. Surgical planning-fx repair/osseous debridement
  3. Assess vascularity
  4. Limited info about articular cartilage
  5. Guidance FNA, BX
36
Q

CT Pros

A
  1. Exam quick
    - less recumbency/anesthesia
    - can go directly to sx/tx
  2. Less expensive than MRI
    - exam and anesthesia time
37
Q

CT Cons

A
  1. Ionizing radiation
  2. Anesthesia
  3. Less soft tissue detail than MRI
  4. Limited by anatomy
    - no shoulders/pelvis/thorax/abdomen/axial skeleton in adults