Introduction to Musculoskeletal Ultrasound Johannes Roth MD, PhD, FRCPC, RhMSUS Professor of Pediatrics University of Ottawa Gurjit S Kaeley MBBS, MRCP, RhMSUS Professor of Medicine Division Chief Director of Musculoskeletal Ultrasound University of Florida College of Medicine, Jacksonville. Disclosures Johannes Roth MD, PhD, FRCPC, RhMSUS Nothing to disclose Gurjit S Kaeley MBBS, MRCP Unrestricted equipment loan from Esaote Evidence Based Medicine Key References Stefano Bianchi, Carlo Martinoli.Ultrasound of the Musculoskeletal System. Springer 2007. M Backhaus et al. Guidelines for musculoskeletal ultrasound in Rheumatology. Ann Rheum Dis 2001;60:641 649. Wakefield RJ et al. Proceedings from the OMERACT Special Interest Group for Musculoskeletal Ultrasound including definitions for ultrasonographic pathology. J Rheumatol 2005; 32:2485 2487 1
Objectives After attending this session you should be able to Understand the basics of ultrasound scanning Recognize sonographic appearances of skin, tendons, muscles, nerves, bone, fluid collections and inflammatory lesions. Able to perform a basic knee sonographic exam Understand the principles of ultrasound guided joint injections Understand the application of musculoskeletal ultrasound to rheumatological practice. Agenda Introduction Basic Physics Concepts Terminology Basic principles of ultrasound scanning Identify normal tissues Sonography of the Knee Musculoskeletal Ultrasound in Rheumatological Practice Guided interventions Billing and Coding Ultrasound Equipment Ultrasound machine Transducers: High frequency (High resolution, less penetration) Low frequency (Low resolution, deep penetration) Gel Transducer cover Computer/printer 2
What is ultrasound? Ultrasound imaging uses transmission and reflection of high frequency longitudinal mechanical waves (ultra sonic waves) Image information is provided by energy of waves reflected from surfaces between different tissues Wave propagation speed allows calculation of distance Frequency Human hearing is in the 20-20,000 Hz range. Frequency of an ultrasound wave is above 20,000 Hz (20 KHz) Medical ultrasound commonly is in the 5-22 MHz range. Generation of ultrasound beam 1) conversion of electrical to mechanical (sound) = converse piezoelectric effect (Gabriel Lippman 1881). 2) Conversion sound to electrical energy = piezoelectric effect (Pierre Curie 1880) one piezoelectric crystal = ultrasound wave, summation of waves=ultrasound beam 3
Reflection Strong specular reflections bright dots (hyperechoic), gallstone Weak diffuse reflections grey dots (hypoechoic), solid organs No reflection dark dots (anechoic), fluid Deep structures hypoechoic, attenuation limits beam transmission Reflection Reflection at the interface of two tissues depends on Difference in the acoustic impedance of the tissues Angle of incidence of the sound beam Reflection of sound increases with the increase in difference in acoustic impedance. Typical reflection at soft tissue interfaces 99.9% soft tissue air 40% muscle and bone < 1% soft tissue to soft tissue Terminology Echoic - white Hyperechoic white/grey Isoechoic - grey Hypoechoic grey/dark grey Anechoic - black 4
Direction of the beam Anisotropy Ultrasound Grayscale or B-Mode Doppler. 5
Doppler Effect Christian Doppler (1803-1853) The observed frequency of a wave depends on the relative speed of the source and the observer. Born in Salzburg Professor of Mathematics and Physics in Prague, Banská Štiavnica/Slovakia and Vienna Doppler Effect Doppler detects the Frequency shift ft fr 6
Doppler equation 2 ft V cosine Frequency (fd) = ft - fr = C Velocity V and Angle dependent Cosine 90 degrees = 0 Detects only movement towards or away from the transducer Doppler modalities Color Doppler Angle dependent Determines mean velocity Image relates to velocity Power Doppler Angle independent can be displayed with colour Summarizes all signals Signal relates to number of erythrocytes Enough Physics Let s get started 7
How to hold the probe The need for gel a lot of gel!!! 8
Pressure and Gel! Instrument settings Knobology after choosing your preset adjust: Frequency Depth Focus Gain PRF for Doppler Then say cheese and push the freeze button The Impact of Ultrasonic Frequency on Attenuation Frequency = Attenuation; Attenuation = Penetration 9
Frequency: Penetration vs Resolution 10 MHz 18 MHz DEPTH Should be adjusted so area of interest is centred, seen completely but is not too large or too small. Focus Should be at the level of the area of interest 10
GAIN Adjusts the amplification of echoes on the monitor Brightness Compensates for attenuation Will increase brightness of the entire image TGC TGC = Time Gain Compensation Adjusts the Gain at specific depths Agenda Introduction Identify normal tissues Skin and subcutaneous tissue Muscles Nerves Tendons and demonstrate anisotropy Bone and cartilage Blood vessels Joint structure Selected artifacts Sonography of the Knee Musculoskeletal Ultrasound in Rheumatological Practice Guided interventions Billing and Coding 11
Which tissues are important? Fluid anechoic, posterior enhancement, compressible 0.2 cm Fluid Compression (Doppler!) Can be more difficult in deeper structures 12
Cartilage Homogeneous anechoic layer lining the bony cortex with superficial and deep margins that characteristically appear thin, sharp, continuous and regularly hyperechoic Careful technique and positioning is everything! Blood Vessels 13
Tendon and tendon sheath Hyperechoic (relative to subdermal fat) fibrillar pattern (ie, hyperechoic parallel lines in longitudinal planes and hyperechoic dots in transverse planes) with a thin hypoechoic (relative to tendon fibres) halo in transverse or thin hypoechoic lines above and below the tendon in longitudinal views. Tendon fibrillar Long Trans Enthesis Achilles Tendon Fat Pad Bursa / Fibrocartilag Calcaneus Fibrocartilage 14
Nerve fascicular Nerve fascicular Tendon and Nerve Median nerve Median N Flexor tendon Flexor tendon Flexor T 15
Bone and Muscle And now try it yourself!!! Practical Session Objectives Identify Bone Joint Structures Muscle Tendons Nerve Demonstrate Anisotropy Artifact 16
Musculoskeletal Ultrasound of The Knee Objectives Scan familiar anatomy This session is aimed to give you a taste of what you can do with familiar knowledge. We will be asking you to perform limited scanning. Full standard scans are not difficult to perform once basic training has been acquired Guidelines for Musculoskeletal Ultrasound in Rheumatology Knee Standard scans of the knee 1. Suprapatellar longitudinal scan in neutral position 2. Suprapatellar transverse scan in neutral position 3. Suprapatellar transverse scan in maximal flexion 4. Infrapatellar longitudinal scan 5. Infrapatellar transverse scan 6. Medial longitudinal scan 7. Lateral longitudinal scan 8. Posterior medial longitudinal scan 9. Posterior lateral longitudinal scan 10. Posterior transverse scan 17
Knee - Synovial Spaces All illustrations in this presentation adapted from C Martinoli Knee Ligaments and Tendons BF ITB QT SM LCL LCL MCL MCL ST Lateral Anterior Medial Suprapatellar longitudinal scan (30 Flexion) 30 Flexion Different positions might be necessary for Doppler!!! straight 18
Suprapatellar longitudinal scan (30 Flexion) Fat pad Patella Fat pad Recess Femur Growth Plate Schmidt-WA ARD 2004: Sagittal midline 2.4 ± 1.2 mm Suprapatellar transverse scan (30 flexion) Pat Tendon Tendon Femur Bone Suprapatellar transverse scan in maximal flexion Schmidt-WA ARD 2004: Cartilage 3.1 ± 0.7 mm 19
The parapatellar recess Lateral Medial lateral retinaculum PATELLA PATELLA FEMUR FEMUR medial retinaculum Infrapatellar long prox Location of Bursa Tendon Patella Hoffa Schmidt-WA ARD 2004: Patella tendon 2 cm distal Patella 3.2 ± 0.7 mm Infrapatellar longitudinal distal Bursa infrapatellaris superficialis Hoffa Bursa infrapat profunda Tibia 20
Infrapatellar transverse scan Patella Tendon Condyle Gout Double Contour Sign Knee: Maximum Flexion Transverse Long Double Contour Interface Sign Chondrocalcinosis 21
Practical Session Objectives Scan and identify Quadriceps tendon in orthogonal planes Patellar Ligament in Orthogonal planes Inspect the femoral condyle cartilage with the knee in maximal flexion. Agenda Introduction Identify normal tissues Sonography of the Knee Musculoskeletal Ultrasound in Rheumatological Practice Guided interventions Billing and Coding US Guided Injection Region: Suprapatellar Recess Diag copyright Primal and Servier 22
Accessing the Recess Confirming the Position Longitudenally Injecting Under Visualization 23
Acute Podagra: 1 st MTP Aspiration US Guided SASD Injection Deltoid Fat Stripe SASD SST SASD Subacromial subdeltoid bursa Carpal Tunnel Injection 24
2 nd MCP INJECTION Metacarpal Head Metacarpal Head Agenda Introduction Identify normal tissues Sonography of the Knee Musculoskeletal Ultrasound in Rheumatological Practice Detection of common pathology Guided interventions Billing and Coding Ultrasound Billing and documentation Verify your State s nuances in what is allowable for medicare Document diagnosis and indication for ultrasound Complete Scan: 76881 Directed Scan: 76882 Right sided scan Code 76881/2 modifier RT, use second modifier 59 for upper and lower extremity scan Left sided scan Code 76881/2 modifier LT, use second modifier 59 for upper and lower extremity scan Bilateral scan Bill twice using above codes 25
Procedure Billing and documentation Procedure code Use appropriate procedure code Ultrasound guided needle placement Code 76942 CHANGED IN 2015 SEE NEXT 2 SLIDES Use modifier 25 with office visit code Document Diagnosis Indication for US guidance Procedure documentation Aftercare Must have a permanent US picture of needle in target site New for Medicare 2015 2015 Billing Code Changes 20604 Arthrocentesis, aspiration and/or injection, small joint or bursa (e.g., fingers, toes); with ultrasound guidance, with permanent recording and reporting 20606 Arthrocentesis, aspiration and/or injection, intermediate joint or bursa (e.g., temporomandibular, acromioclavicular, wrist, elbow or ankle, olecranon bursa); with ultrasound guidance, with permanent recording and reporting 20611 Arthrocentesis, aspiration and/or injection, large joint or bursa (e.g., shoulder, hip, knee, subacromial bursa); with ultrasound guidance, with permanent recording and reporting 2015 Code Changes Procedure CPT 2014 CPT 2015 Small Joint Injection + MSK US 20600 + 76942 20604 Intermediate Joint Injection + MSK US 20605 + 76942 20606 Large Joint Injection + MSK US 20610 + 76942 20611 Tendon Sheath Injection + MSK US 20550 + 76942 No change Tendon Origin / Insert. Injection + MSK US 20551 + 76942 No change Carpal Tunnel Injection + MSK US 20526 + 76942 No change Injection, enzyme Dupuytren s + MSK US 20527 + 76942 No change Ganglion Cyst Injection + MSK US 20612 + 76942 No change ACR Update Nov 6 th 2014 (email) 26
QUESTIONS? 27