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Musculoskeletal Ultrasound Topics

• What is ultrasound ?• How does it work ?• Equipment• Artefacts• Safety • What does it offer to those interested in

musculo-skeletal problems ?

What Is Ultrasound?

• Sound waves with frequency above 20,000hz.

• Frequency for musculoskeletal use 5 to 25 mega hz

• Use of ultrasound depends on detecting echoes.

Components of an Ultrasound System

• Source of ultrasound waves

• Echo detection system

• Computer processing

• Image Display

• Image storage

Ultrasound Production and Detection Systems

• Piezo-electric crystals• Vibrate when exposed to electrical current• Produce electrical output when excited by

vibration.• Parallel arrays• Acoustic focussing• 1% of time emitting ultrasound• 99% of time listening

Piezo electric crystals

Ultrasound waves

Ultrasound Production and Detection Systems

Focussing by acoustic lens

Piezo electric crystals

Ultrasound waves

Processing

Ultrasound Production and Detection Systems

Piezo electric crystals

Ultrasound waves

Cyst

Ultrasound Processing and Display

• Huge progress with advances in computers.

• Display modes

• B Mode - brightness mode, grey scale

Ultrasound Equipment

• Radiology department based systems £120-150K

• Philips, Siemens, GE, Accuson, etc

• Late 1990’s new companies involved.

• Dedicated musculo-skeletal machines.

• Portable machines

Diasus Musculoskeletal Ultrasound

• Dedicated musculoskeletal machine

• £30-35 K• Variety of probes • The machine I trained on

and still use regularly.• No colour Doppler

Portable/Hand Held Ultrasound Machines

• Sonosite

• Portable can be run off battery.

• 5-10mHz probe for musculoskeletal work

• £15 – 25 K

Sonosite Portable Machines

Handheld Version Makes Imaging Technology Battle-Ready

Ultimate Ultrasound

March 28 — A technology widely used for a glimpse at the soon-to-be-born has now been turned into a battlefield unit that may help keep soldiers from dying in Iraq.

What Do You Need To Perform Ultrasound

Successfully ?• Equipment

• Training

• Anatomy knowledge

• Time

What Does Ultrasound Offer

• Diagnosis

• Assessment of disease activity and treatment monitoring

• Guiding procedures– Aspiration 3x normal likely to obtain fluid– Injection accuracy increased from 59% to 96%

Diagnosis

• Extends clinical examination• More sensitive for detecting effusions and

synovitis than clinical exam• Better than MRI for tendon and tendon sheath

problems• 7-10 x more sensitive than plain x-ray at detecting

erosions.• Equals MRI for detecting synovitis and erosions. • Equals MRI for soft tissue shoulder problems.

Safety Issues• BMUS Guidelines• British Medical

Ultrasound Society• 15 points

1. Medical endorsement2. Operator training3. Awareness of machine

factors4. Initial power setting5. Exposure time6. Stationary probe7. Probe self heating

8. Pre-existing temperature elevation

9. Sensitive tissues10. Pulsed doppler11. Thermal and

mechanical indices12. Doppler for fetal heart

monitoring13. Peripheral pulse

monitoring14. Transcranial

ultrasound 15. Non-diagnostic uses of

ultrasound equipment

Future Developments

• 2D, 3D, 4D

• High resolution power Doppler

• Microbubble contrast

Future Developments

• High resolution power Doppler

• Microbubble contrast

Future DevelopmentsPanorama Views

Advantages of Musculoskeletal Ultrasound

• Increasingly available

• No major safety issues

• Extends clinical examination

• More sensitive than plain radiology

• As sensitive as MRI for erosions and synovitis.

• Allows more accurate injection and more successful aspiration.

• Dynamic, allows movement.

Ultrasound of Normal Musculoskeletal Tissues

Ultrasound of Normal Musculoskeletal Tissues

• Tendon and ligament• Muscle• Nerve• Bone• Joints• Cysts, bursi and effusions• Blood vessels• Fat

Tendons

Muscle Longitudinal Cross section

Nerves

Bone

MCP Joint

MCP head

Phalangeal head

Cartilage

Extensor tendon

Bursi, Cysts and Effusions

Pre-Tibial Bursitis

Knee Effusion

Cyst

Artery

Artery

Veins

Fat

Common Artefacts

• Anisotropy

• Reverberation

• Acoustic shadowing

• Increased transmission through cyst

Piezo electric crystals

Ultrasound waves

Anisotropy

Anisotropy Achilles Tendon

Reverberation

Piezo electric crystals

Ultrasound waves

Bone

Acoustic shadowing

Acoustic shadowing

Increased Transmission Thru Cyst

Ultrasound PathologyHand and Wrist

Tenosynovitis

Flexor Tenosynovitis

Joints

Erosions

1-2mm erosion

2-4mm erosion

>4mm erosion

Thanks to David Kane

Effusions and Synovitis

Thanks to David Kane

Assessment of Synovitis using Power Doppler

MCP joint

Erosion

Normal US 1st MTP

.

Patella tendonitis or jumpers knee. Patella tendon insertion hypo-echoic and swollen.

Patella

Patella tendon

Hypo-echoic area

Osgood Schlatters

• Patella tendon

• Tibial tuberosity

.

Baker’s Cyst

Cyst

.

Medial head of gastrocnemius

Bakers Cyst

Muscle Tears

Achilles Tendinopathy

Achilles Tendinopathy

Calcification in Achilles Tendon

Achilles Tendon

Insertion Problems

Achilles Tendon Rupture

Tibialis Posterior Tenosynovitis

Stress Fractures