Equine Flashcards
According to the article ‘Abnormal imaging findings of femoral 3rd trochanter in 20 horses’ What do they recommend when a horse comes in for upper pelvic limb lameness?
Shields, G., ‘Abnormal imaging findings of femoral 3rd trochanter in 20 horses.’ VRU. Pre-published
Whenever a pelvic ultrasound is performed - ultrasound of the femoral trochanter should be performed as well.
What muscle groups attach at the 3rd trochanter of the femur?
Shields, G., ‘Abnormal imaging findings of femoral 3rd trochanter in 20 horses.’ VRU. Pre-published
Superficial gluteal muscles, and secondary site of insertion of the tensor fasciae latae
At recheck examinations of 3rd trochanter fractures - what did recheck US and Nuclear scintigraphy findings show?
Shields, G., ‘Abnormal imaging findings of femoral 3rd trochanter in 20 horses.’ VRU. Pre-published
US: Up to 3/4 had similar appearance (cranial displacement of fracture fragment) - likely due to the fracture healing by fibrous union.
Nuclear scintigraphy: mixed bag. Some had decreased IRU, some had increased IRU.
How did IRU of the third trochanter (due to fracture) relate to clinical lameness, duration of lameness and outcome?
Shields, G., ‘Abnormal imaging findings of femoral 3rd trochanter in 20 horses.’ VRU. Pre-published
Did not relate to degree of lameness, duration or outcome.
Describe the appearance of the starry sky hepatic pattern in horses
Starry sky hepatic US pattern in horses. VRU 52.5
numerous, small, hyperechoic foci (some of which cast an acoustic shadow), distributed randomly throughout all of the hepatic parenchyma
What was most common clinical sign in horses that were found to have a starry sky hepatic pattern on US?
Starry sky hepatic US pattern in horses. VRU 52.5
weight loss, anorexia
Was underlying liver dz common?
Starry sky hepatic US pattern in horses. VRU 52.5
9/18 horses had elevated liver enzymes
5/18 had primary liver dz
3/18 had severe dz
Believe that granulomas were not related to hepatic disease
What is the cause of the starry hepatic pattern on equine us?
Starry sky hepatic US pattern in horses. VRU 52.5
Granulomas
Also: fibrosis, eosinophilic inflammation or mineralization
ALL horses had granulomas at necropsy. Whereas, not all samples (36%) that were biopsied had granulomas present.
Why does the magic angle artifact occur?
Effect of DDFT orientation on MRI signal intensity in isolated equine limbs - the magic angle effect VRU 43.5
The angel at which the dipolar interaction between two nuclei is zero.
Dipole-dipole interactions will result in loss of T2 magnetization and loss of signal within a signal. Without interactions -signal will be increased.
How can the magic angle artifact be avoided?
Effect of DDFT orientation on MRI signal intensity in isolated equine limbs - the magic angle effect VRU 43.5
Using longer TE times (most common in
What is the equation of the magic angle artifact?
Which angle is the magic angle, what angles can this artifact be seen at?
Effect of DDFT orientation on MRI signal intensity in isolated equine limbs - the magic angle effect VRU 43.5
When 3 cos^2(angle)-1 = 0
54.74 (55)
Can be seen 50-60.
Which MR sequence is not affected by the magic angle artifact and why?
Characterization of the magic angle effect in the equine DDFT using a low-field MR system VRU 50.1
T2 (Long TE times)
Unlike in high field MR studies, in this study:
Characterization of the magic angle effect in the equine DDFT using a low-field MR system VRU 50.1
They found that there could be focal linear (rather than diffuse) effects associated with the dorsal vs palmar aspect of the DDFT in different areas of the tendon. Why is this?
Palmar aspect of DDFT have fibers that diverse from the middle phalanx to the navicular
Dorsal aspect of DDFT have fibers that diverge from navicular to insertion of impar ligament.
These fibers at these divergences are parallel to each other - if palmar aspect of DDFT is hyperintense proximally, then dorsal aspect of DDFT is hyperintense as well.
In this article:
Characterization of the magic angle effect in the equine DDFT using a low-field MR system VRU 50.1
What other ligament was affecte by the magic angle artifact?
Collateral ligaments of the DIP.
If there is hyperintensity of the collateral ligament, the DDFT should be evaluated palmar aspect of the DDFT on the same side (seen in all 12 cases)
What is the general shape of the DDFT in different areas?
Quantitative evaluation of equine DDFT morphology using MRI VRU 45.2
Distal to navicular bone - the DDFT is crescent shaped
At the navidular - the DDFT is more rounded
Proximal to the navicular bone - the DDFT is bilobed in appearance
Where is the greatest CSA of the DDFT?
Quantitative evaluation of equine DDFT morphology using MRI VRU 45.2
Mid-navicular bone
Where was the greatest medial to lateral measurement?
Dorsal to palmar?
Quantitative evaluation of equine DDFT morphology using MRI VRU 45.2
ML - mid-navicular
DP - proximal to navicular
Was there significant correlation between hoof circumference and DDFT?
Weight and DDFT?
Quantitative evaluation of equine DDFT morphology using MRI VRU 45.2
Hoof circumference/DDFT - no
Weight/DDFT - yes
What changes in the DDFT were seen in horses with lameness?
Quantitative evaluation of equine DDFT morphology using MRI VRU 45.2
Increased signal
Loss of symmetry
Loss of correlation between the measurements
Increased Cross sectional areas in core lesions only
How did measurements compare between the medial and lateral lobes?
Between different limbs?
Quantitative evaluation of equine DDFT morphology using MRI VRU 45.2
Similar in patients with clinically normal feet
Animals with lesion sin the DDFT - the measurements different, and there was lack of symmetry.
What is a typical bone edema pattern?
MRI findings in the equine DDFT and distal sesamoid bone in advanced navicular disease - an ex vivo study VRU 46.4
Increased PD and T2 signal of the bone marrow
Decreased T1 signal
What were two causes of loss of signal of the T1 hyperintense bone marrow within the navicular bone on histology?
Quantitative evaluation of equine DDFT morphology using MRI VRU 45.2
Degenerative or necrotic fat
Thickened trabecular bone, and formation of bone islands
What is the classification scheme of mineralization of the ungual cartilages?
Grade 0 - no ossification
Grade 1 - Minimal ossification at the base of the cartilage
Grade 2 - slight ossification in the base of the palmar portion of the DIP joint
Grade 3 - Moderate ossification reaching the proximal border of the navicular bone
Grade 4 - Advanced ossification above the navicular bone into the middle portion of the proximal third of the middle phalanx
Grade 5 - extensive ossification close to the middle portion of the proximal third of the middle phalanx.
What can lead to ossification of the collateral cartilages?
Collateral cartilage ossification of the distal phalanx in the brazilian jumper horse. VRU 43.5
impact, hereditary factors, poor limb conformation, incorrectly fitted shoes
Which horses are likely to show lameness related to ungual cartilages.
Collateral cartilage ossification of the distal phalanx in the brazilian jumper horse. VRU 43.5
Horses with a large sole (draft horse) - do not show lameness
Small horses, with narrow sole and minimal hoof expansion are more likely to show lameness
Of the population in the article: Collateral cartilage ossification of the distal phalanx in the brazilian jumper horse. VRU 43.5
Which horses were more likely to have a higher incidence of ossification of the ungual cartilages (grade 3-5)?
Horses in full show mode (jumper horses)
Where was ossification more likely to occur in the population in the article:
Collateral cartilage ossification of the distal phalanx in the brazilian jumper horse. VRU 43.5
At the base of the cartilage (86.4%), rather than via a separate site of ossification (6.6%)
What are the five ligaments associated with the ungual cartilages? What do they connect?
Fractures of the distal phalanx and associated soft tissue and osseous abnormalities in 22 horses with ossified sclerotic ungual cartilages diagnosed with MRI. VRU 52.4
1) Chondrocoronal ligament: dorsal proximal aspect of ungual cartilage to dorsomedial/lateral margin of the middle phalanx
2) Chondrotendonous ligament - connects dorsal aspect of the cartilages to the extensor process of the distal phalanx
3) Chondrocompedal - attaches palmar proximal aspect of the cartilages to the distal aspect of the proximal phalanx
4) Chondrosesamoidean - axial aspect of the ungual cartilages to abaxial margins of the distal sesamoid bone
5) Chondroungular ligament - connects abaxial distal margin of the ungual cartilage to the palmar process of the distal phalanx
Describe the fractures that were seen in the article:
Fractures of the distal phalanx and associated soft tissue and osseous abnormalities in 22 horses with ossified sclerotic ungual cartilages diagnosed with MRI. VRU 52.4
simple, non-articular fractures that were non-displaced
Located in the palmar aspect of the distal phalanx
Oriented in an axial proximal to abaxial distal and palmar to dorsal orientation extending from base of an ossified cartilage
What imaging characteristics did the fractures have on each MR sequence?
Fractures of the distal phalanx and associated soft tissue and osseous abnormalities in 22 horses with ossified sclerotic ungual cartilages diagnosed with MRI. VRU 52.4
Hyperintense on T1, T2, PD and STIR images.
The hyperintensity on the STIR image extended beyond the margins of the fracture
What grade of ossification of the ungual cartilages were seen associated with these fractures?
Fractures of the distal phalanx and associated soft tissue and osseous abnormalities in 22 horses with ossified sclerotic ungual cartilages diagnosed with MRI. VRU 52.4
Moderate-severe in the majority
What soft tissue changes were seen associated with the fractures of the distal phalanx in the article:
Fractures of the distal phalanx and associated soft tissue and osseous abnormalities in 22 horses with ossified sclerotic ungual cartilages diagnosed with MRI. VRU 52.4
Increased signal intensity/enlargement of colalteral ligaments
increased or decreased signal of the chondrocoronal, chondrosesamoidean on PD, T2 and STIR images
