Equine Diagnostic Radiography & Ultrasonography Radiography Distal Limb T… · • Echogenicity...

1

Equine Diagnostic

Radiography & UltrasonographyDr. Russell Tucker DACVR

Prof Emeritus, WSU

90

~30

DLPMO ~ projects

medial forward

lateral backward

~30PL to DM projection

2

DMPLO (PL-DMO)

~ projects

lateral forward

medial backward

EQUINE DISTAL LIMB

TENDONS & LIGAMENTS

Anatomic Abbreviations:

SDF = Superficial Digital Flexor

DDF = Deep Digital Flexor

ICL = Inferior Check Ligament

SL = Suspensory Ligament

AL = Annular Ligament

DAL = Digital Annular Ligament

DDAL = Distal Digital Annular Ligament

SDSL = Straight Distal Sesamoidean Ligament

ODSL = Oblique Distal Sesamoidean Ligament

PL = Plantar Ligament

CL = Collateral Ligament

1. Longitudinal

Scanning Planes

2. Transverse

3. Oblique

2

1

3

Sedated & Placed in Stocks

Clip & Shave Both Legs

or

Clean & Wet Hair (diluted 30% alcohol)

Scan in Direction of Hair

Preparation Standoff Pads

or

Offsets

“sonolucent”

material for

scanning irregular

surfaces

&

superficial structures

3

Extended FOV

proximal distal

5 cm

Elasticity Imaging DDF lesion

Metacarpus

Proximal MCIII longitudinal

4 cm “footprint” 12 MHz linear probe, using ACC bone as reference

- with 5 focal zones activated & uniform gain across FOV

Metacarpus

Mid-Distal MCIII longitudinal

Metacarpus

Distal MCIII & Inter-Sesamoid longitudinal

Suspensory Branch Insertion

transverse longitudinal

Insertion onto abaxial fossa of proximal sesamoid bone

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Suspensory Branch

Insertion

longitudinal

transverse

TRANSVERSE IMAGES

• Orthogonal to Longitudinal Images

• Zones 1a, 1b --- 3a, 3b on front limbs

• Zones 1a, 1b --- 4a, 4b on rear limbs

• Use cm distal to LANDMARKS

• Distal Accessory Carpal Bone (DACB)

• Tuber Calcaneous Bone or MT4 head

MCIII 4 cm distal to accessory carpal boneTransverse

41A

A

4 cm “footprint” 12 MHz linear probe, using ACC bone as reference

- with 5 focal zones activated & uniform gain across FOV

MCIII 8 cm distal to accessory carpal boneTransverse

MCIII 12 cm distal to accessory carpal bone

Transverse


Transverse

5


Transverse


Transverse

Suspensory branched

~proximal pouch of fetlock joint


Transverse

Suspensory Branch Insertion

may require stand off pad

1 cm


Transverse

Proximal sesamoids axial surfaces


Transverse

Palmar Annular Ligament Thickness

~ requires dynamic imaging to visualize

REAR LIMBS

• Orthogonal to Longitudinal Images

• Zones 1a, 1b --- 3a, 3b on front limbs

• Zones 1a, 1b --- 4a, 4b on rear limbs

• Use cm distal to LANDMARKS

• Distal to 4th Metatarsal Head (MT4)

• Distal to point of Tuber Calcaneus

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Distal Tarsus -Transverse

DDF exiting tarsal canal

MTIII 4 cm distal to Tarsus

Transverse

* need to image slightly medially for entire DDF


Transverse


Transverse


Transverse

Identical to front legs

~may require stand off pad for PaAL

Tendon & Ligament Pathology

• Compare Sides RT vs LT

• Sequential Scanning Protocol

• Record in at least 2 anatomic planes

– Sagittal (longitudinal)

– Transverse (axial)

– Oblique Planes may be required

*Carefully document & describe lesions

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Tendon & Ligament Scanning

• Clip or Not ?

• Shave or Not ?

• Fiber pattern important

• Try 30% diluted alcohol

• Image 2 orthogonal planes

– Sagittal (longitudinal)

– Transverse (axial)

– Oblique scan planes

Compare legs

RH norm prox suspensory

LH abnormal proximal suspensory

Compare size & echogenicity & fiber patterns

LF vs RF

ICL size

Compare to other limb

or medial vs lateral

LH medial Susp

LH lateral Susp

Loss of fiber pattern

• Cross-sectional area

• Region of involvement

• Length of lesion

• Echogenicity

• Focal or diffuse

• Fiber pattern

• Change over time

25 mm2

Lesion Characterization & Descriptions

DDF

Cross Sectional Area of Lesions

• Trace the tendon

1 = total tendon

• Trace the lesion

2 = lesion

• Calculate X-sec %

ROI 1 / ROI 2 = 38 %

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5 yr THB gelding RF lame

~ swelling above fetlock

R

R

R

DMPLO

projects medial

sesamoid caudally

5 yr THB gelding RF lame

~ swelling above fetlock

RF Suspensory med branch

- 5.28 cm outline/ 1.92 cm2

- hypoechoic & fiber loss

RF Suspensory lat branch (norm)

- 4.54 cm outline/1.47 cm2

- uniform fiber pattern

Lat Branch

Med Branch

Echogenicity of Lesions

• Hypoechogenicity

– Acute & Healing Phases

• Hyperechogenicity

– Healing & Chronic Phases

• Calculate Abnormal %

– % change over time

Fiber Integrity of Lesions1. Fiber Loss & Disruption

– Acute & Healing Phases

2. Fiber Replacement

– Healing & Chronic Phases

3. Fiber Restructuring

– % change over time

• Type I replaces Type III collagen

• Longitudinal orientation

• May require 6-12 months to occur

• Forever decreased strength

Focal vs Diffuse

Common digital extensor tendon over medial carpusDLPMO

Focal vs Diffuse lesions

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Core Lesions

~ contained w/in interior

Peripheral Lesions

~ extend to edgeLesion: Proximal to Distal

10-22 cm DACB

SDF Tear

10cm

12cm

15cm

22cm

SDF

DDF

Acute Inflammatory Stage

~ edema & hemorrhage (hypoechoic)

Initial scan DDF

90 days lay off

Healing 3-6 months

Type I replaces Type III collagen

~ restores fiber orientation

PROGRESSIVE

REHABILITATION

Month 0-2

Stall rest & hand walk

30 min/d Mon 1, 45 min/d Mon 2

Month 2-3


25-45 min/d, jog 5 min/d

Month 4-6


20-45 min/d, jog 10 min/d

Peri-tendinal effusions

• Amount

• Cellularity

• Fibrin

• Adhesions

• Tendon sheath

• Synovium

10

Fluid & Effusion

Composition10 yr gelding THB - chronic RF fetlock swelling & lameness

R

R R

Lat RF collateral transverse

Dynamic Imaging for Adhesions

• Critical for follow-up exams

• Exact location of lesion

• Size & characteristics

• Compare to other limb

Accurate & Detailed

Lesion DescriptionsQuestions???

Equine Diagnostic Radiography & Ultrasonography Radiography Distal Limb T… · • Echogenicity...

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Transcript of Equine Diagnostic Radiography & Ultrasonography Radiography Distal Limb T… · • Echogenicity...