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 £ K 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 endorsement 2.Operator training 3.Awareness of machine factors 4.Initial power setting 5.Exposure time 6.Stationary probe 7.Probe self heating 8.Pre-existing temperature elevation 9.Sensitive tissues 10. Pulsed doppler 11. Thermal and mechanical indices 12. Doppler for fetal heart monitoring 13. Peripheral pulse monitoring 14. 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 Developments Panorama 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

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

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

Increased Transmission Thru Cyst

Ultrasound Pathology Hand 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 1 st 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

Calcification in Achilles Tendon

Achilles Tendon Insertion Problems

Achilles Tendon Rupture

Tibialis Posterior Tenosynovitis

Stress Fractures