Week 3 Lesson 18 Tendons and ligaments diagnostic imaging

What is the range of sound frequencies that the human ear can perceive?

Sound in the range of 20 to 20,000 Hz.

Beyond what frequency is sound officially classified as ultrasound?

Sound over 20,000 Hz.

What is the measurement unit used for the number of sound cycles per second?

Hertz (Hz).

What is the relationship between the frequency of a sound wave and its wavelength?

The higher the frequency, the shorter the wavelength.

How are frequency and penetration depth related in ultrasonography?

They are inversely related.

What is a characteristic of using a low-frequency transducer like 5 MHz?

It can penetrate deeper but provides less detail.

What is the advantage of using a high-frequency transducer like 8 MHz?

It provides increased detail but penetrates less.

Which imaging modality is the diagnostic method of choice for assessing equine tendon injuries?

Ultrasonography.

List two imaging modalities besides ultrasound used to evaluate equine limb injuries.

Radiography and MRI.

What are the three main components of a portable ultrasound unit?

Screen, control panel/keyboard, and transducer.

What does B-mode stand for in ultrasound imaging?

Brightness mode.

How many dimensions are represented in a B-mode ultrasound image?

Two dimensions (2D).

What is the common definition of M-mode in ultrasonography?

Motion mode.

List the five primary properties of sound wave interactions with tissues.

Reflection, absorption, scattering, attenuation, and refraction.

What mnemonic is suggested to remember the properties of sound wave interactions?

Rabbits Are Smart And Rapid.

Which tissue types typically cause ultrasound waves to be absorbed?

Bone and minerals.

Which medium is known to be a strong reflector of ultrasound waves?

Air.

What occurs when an ultrasound wave is refracted?

The wave changes direction as it passes through air or tissues.

How is a scattered sound wave described?

It is reflected in all directions by small or irregular surfaces.

What is the specific term for the weakening of sound as it travels through a medium?

Attenuation.

How much sound energy does air attenuate within 0.05 cm using a 2.0-MHz transducer?

Half of the sound energy.

What determines the intensity of pixels on an ultrasound monitor?

The strength of the returning echoes.

What is the characteristic of a tissue to reflect sound waves and produce echoes called?

Echogenicity.

How does an anechoic structure appear on an ultrasound screen?

It appears black.

What is a common synonym for the term anechoic?

Echo-lucent.

How is the term hypoechoic defined?

A low level of gray echoes that appear darker than surrounding tissues.

What does the term hyperechoic describe?

Brighter echoes that appear light gray or white.

What term describes tissues that possess the same level of echogenicity?

Isoechoic.

Which structures in the distal limb are the most echogenic?

Bone and gas.

Which substances are generally the least echogenic in ultrasound terminology?

Fluids such as blood or urine.

What term is used to describe a uniform and smooth tissue texture on ultrasound?

Homogenous.

What does a heterogeneous echotexture indicate?

A mixed or non-uniform echogenicity.

In comparison to tendons, how would you describe the echogenicity of the liver?

The liver is hypoechoic to tendons.

What are the basic surface requirements for equine patient restraint during an ultrasound?

A non-slip surface.

What is the preferred position for a horse during a distal limb ultrasound?

A standing, weight-bearing position.

What is the clipping range for a forelimb ultrasound?

From below the accessory carpal bone to below the fetlock.

What is the clipping range for a hindlimb ultrasound?

From the metatarsal region up to the chestnut.

Why is a dilute chlorhexidine scrub used during patient preparation?

To remove excessive organic matter from the skin.

What substance is applied after alcohol to improve sound wave transmission?

Ultrasound coupling gel.

What type of linear transducers are typically used for equine distal limb imaging?

High-frequency transducers ranging from 7.5 to 16 MHz.

Which transducer type is best for imaging the proximal suspensory ligament?

A micro-convex transducer.

What optional tool helps improve contact and visualize the full width of a tendon?

A standoff pad.

What are the two primary scanning planes used during a patient examination?

Transverse and longitudinal.

What is the typical scanning order for a distal limb ultrasound?

Start proximally and move distally.

How is the forelimb anatomically zoned for ultrasound referencing?

3 zones subdivided into 6 regions.

How is the hindlimb anatomically zoned for ultrasound referencing?

4 zones or 8 regions.

Name the three main soft tissue structures of the distal limb from superficial to deep.

The SDFT, DDFT, and SL.

What does the acronym SDFT stand for?

Superficial Digital Flexor Tendon.

What does the acronym DDFT stand for?

Deep Digital Flexor Tendon.

What is the full name of the SL in the horse's limb?

Suspensory Ligament.

What is the synonym for the Accessory Ligament of the DDFT?

Inferior check ligament.

How does a normal tendon appear in a longitudinal scan?

Uniform, even, regular striations with hyperechoic interfaces.

What are the hyperechoic interfaces in a longitudinal tendon scan separated by?

Anechoic spaces representing the endotenon.

What is the endotenon composed of?

Loose, vascularized connective tissue.

How does a normal tendon appear in a transverse scan?

A coarse granular pattern of densely packed echogenic dots.

What forms the hyperechogenic interface on the surface of a tendon in a transverse scan?

The paratenon and overlying fascia.

What is the shape and location of the SDFT just below the carpal joint?

It is oval and located palmaro-medial to the DDFT.

How does the shape of the SDFT change in the mid-metacarpal region?

The dorsal aspect becomes concave, creating a crescent shape.

Describe the SDFT in the distal metacarpus.

It becomes gradually thinner dorso-palmarly and more symmetrical.

What is the manica flexoria?

A thin membranous ring formed by the SDFT around the DDFT in zone IIIb.

Where does the DDFT start in relation to the SDFT?

It starts dorsolateral to the SDFT.

What is the shape of the DDFT throughout its path in the metacarpus?

It remains oval in shape.

What are the three portions of the suspensory ligament?

Proximal origin, the body, and two branches.

Why might the suspensory ligament look different in young horses?

Muscle fibers can give it a mottled, hypoechoic appearance.

What is the cross-sectional shape of the origin and body of the suspensory ligament?

Rectangular.

How does the echogenicity of the suspensory ligament body compare to flexor tendons?

Coarser, more heterogeneous, and less echogenic.

What is the shape of the suspensory ligament branches distally?

Initially oval and then tear-drop shaped.

What are the Roentgen signs used to detect variations in anatomy via ultrasound?

Number, size, shape, position, and appearance/echogenicity.

What does a hypoechoic change in a tendon usually suggest?

An acute injury involving edema or increased water content.

What does a hyperechoic change in a tendon usually indicate?

A chronic injury.

How does an acute injury appear when the lesion fills with blood and debris?

Heterogeneous and variably echogenic.

What is a common indicator of the quality of tendon repair in a longitudinal image?

The characteristic striated or fibrillar pattern.

How does acute damage typically affect the size of a tendon?

It is usually associated with an increase in size.

What happens to the position of the SDFT in cases of severe damage and elongation?

It becomes displaced medially.

What happens to the torn ends of a tendon following a full transection?

They retract dorsally and distally.

What can cause a tendon to be pushed out of its normal anatomical place?

Peritendinous effusions or bleeding.

What is the "core lesion" in SDF tendinopathy?

A discrete hypoechoic lesion visible in the central region of the tendon.

In which region is an SDFT core lesion most commonly found?

The mid-metacarpal region.

Does a core lesion always result in an increased tendon cross-sectional area?

No, it can occur with or without an increase in area.

What are common causes of SDF traumatic injuries?

Slipped bandages, hitting obstacles, or percutaneous trauma.

What are the ultrasonographic signs of percutaneous injury?

Peritendinous bleeding and hematoma spreading around tendons.

What is the extent of the Digital Flexor Tendon Sheath (DFTS)?

From the distal quarter of the metacarpus to the foot.

Where is a hypoechoic region normally found on the DDFT within the digital sheath?

On the dorsal surface at the proximal limit of the sheath.

What are the structures within the proximal pouch of the digital sheath that join the DDFT?

Synovial plicae.

What is the primary difference between non-septic and septic tenosynovitis?

Non-septic is usually from trauma

What characterizes the effusion in septic tenosynovitis?

It is marked and can range from anechoic to hypoechoic.

What is the "Halo sign" in DDF tendinopathy?

A hypoechoic halo around the DDFT caused by a thickened epitenon.

How does the synovial membrane appear in septic tenosynovitis?

Thickened and edematous.

Where does DDF tendinopathy most commonly occur in the distal limb?

Within the digital sheath or navicular bursa.

How common is DDF tendinopathy in the metacarpal region?

It is considered extremely rare.

What is the appearance of the striation pattern in a healthy adult suspensory ligament?

The pattern is regular.

What happens to the striation of the SL origin in older horses?

It may appear thinner or less marked.

Is the suspensory ligament bilaterally symmetrical in a healthy horse?

Yes, it should be symmetrical at any level.

What does a localized subcutaneous edema on ultrasound indicate?

A degree of traumatic injury.

Which interaction creates the actual ultrasound image?

Reflection.

What is the primary function of ultrasonography in assessing recovery?

To follow up on recovery and response to treatment.

What does the term "paratenon" refer to in a transverse scan?

Part of the hyperechogenic interface on the tendon surface.

How should the transducer be moved to obtain a longitudinal view?

Rotate the transducer 90 degrees from the transverse plane.