Ultrasound of muscle disorders

Transcription

1 Ultrasound of muscle disorders Sigrid Pillen MD PhD Pediatric neurologist The Netherlands

2 Disclosures None

3 "Muscle ultrasound disclaimer"

4 Muscle ultrasound Introduction Specific NMD Quantification Dynamic imaging Does US help diagnose NMD patients?

5 Muscle ultrasound Introduction Specific NMD Quantification Dynamic imaging Does US help diagnose NMD patients?

6 Muscle ultrasound: introduction

7 Introduction: muscle ultrasound Rectus femoris 3.12 cm vastus femur Normal quadriceps muscle

8 Muscle type and build

9 Muscle trauma Normal gastrocnemius Rupture with hematoma

10 Muscle identification & anatomy teaching Flexor carpi radialis and pronator teres muscles in forearm Forearm extensors with panoramic view

11 Needle guidance for EMG / injection therapy

12 Muscle ultrasound in neuromuscular disorders: "256 shades of grey" Healthy Duchenne muscular dystrophy muscle fascia muscle muscle fat fascia fat muscle

13 Muscle ultrasound Introduction Specific NMD Quantification Dynamic imaging Does US help diagnose NMD patients?

14 Every NMD has is own appearance: DMD: homogeneous affected and strong attenuation Healthy Ambulant DMD Advanced stage

15 Typical picture of SMA: severe atrophy and moth eaten pattern

16 Inflammatory myopathies: Focal changes Increased perfusion Fasciitis Calcification

17 Ultrasound in Bethlem myopathy Healthy: central aponeurosis visible Bethlem myopathy: central shadow sign Bonnemann Neuropediatrics 2003

18 Muscle ultrasound Introduction Specific NMD Quantification Dynamic imaging Does US help diagnose NMD patients?

19 Subjectivity of our visual system

20 How grey is that image: age dependency Normal? NMD? Normal aging!

21 Echo intensity: age dependent

22 Quantitative echo intensity analysis Mean echo intensity Compare with normal value Number of SD above normal (= z score)

23 Muscle echo intensity quantified Mean grey value Pro: Well investigated, high diagnostic value Contra: Software and hardware dependent New reference values for each US device

24 Alternative quantification methods Compare with: ROI: Mean grey value Phantom Subcutaneous tissue Backscatter analysis Not software dependent Less but still hardware dependent Luminosity ratio Less but still software and hardware dependent Difficult in very thin patients, edema..

25 QMUS reporting Neuromuscular disorder yes/no? Distribution of abnormalities: differential diagnosis Muscle biopsy location Dermatomyositis Polyneuropathy

26 Optimal muscle biopsy site identification Rectus femoris: + 1 SD Biceps brachii: + 3 SD

27 Optimal biopsy site: avoid "too abnormal" Biceps brachii: only fat/fibrosis Search for muscle with remaining muscle tissue

28 Muscle ultrasound Introduction Specific NMD Quantification Dynamic imaging Does US help diagnose NMD patients?

29 You see more when it s moving

30 Muscles: you see more when they re moving! Healthy biceps brachii muscle

31 US is more sensitive for detecting fasciculations than needle EMG

32 Fibrillations on ultrasound

33 Proof: combined ultrasound EMG EMG needle

34 Great! But... Overall sensitivity 45%, specificity 85% Proximal muscles sensitivity 63% but distally 33% Why? Detection only possible when at least 5 fibs/second Temperature dependent: 100% at 40? C vs 63% at 30? C And: Only with high-end ( expensive ) US-machines: high frequency, high frame rate, little noise van Alfen Muscle Nerve 2010

35 Fasciculations and fibrillations can easily be differentiated

36 Pseudotremor: contraction of large neurogenic units

37 Muscle ultrasound Introduction Specific NMD Quantification Dynamic imaging Does US help diagnose NMD patients?

38 Diagnostic value in children with suspected NMD Visual evaluation: sensitivity at best +/- 70% Quantitative evaluation: sensitivity >90% Positive predictive value: 90% Negative predictive value: 86% Lower sensitivities in: Children < 3 years: sensitivity 75% Mitochondrial myopathies: sensitivity 45 70% Pillen et al NMD 2007 Pillen et al Neuroped 2006 Pillen et al US Med Biol 2006

39 Can US aid in diagnosing ALS? - revised El Escorial criteria

40 Typical US findings in ALS at diagnosis Lots of fasciculations Mild to moderately increased EI Atrophy only in paretic muscles EI Fasciculations Arts US med biol 2008

41 60-year old patient with symptoms suggestive of ALS biceps 2cm: atrophy rectus femoris EI Fasciculations

42 Typical US findings in IBM Severely increased EI Pronounced atrophy No/some fasciculations EI Fasciculations

43 How to differentiate ALS mimics Cervical and lumbar spinal stenosis with myelopathy NO BULBAR OR THORACIC ABNORMALITIES Benign cramp fasciculation syndrome NORMAL EI Inclusion body myositis EI MORE INCREASED, LESS FASCICS Multifocal motor neuropathy (with silent cerebral lesion) FOCAL NERVE ABNORMALITIES?

44 US in ALS and mimics 1. Cross sectional study 48 ALS-patients and 27 ALS-mimics 10 muscles measured for EI and fascics Optimal cut-off point defined:?2 muscles with EI > 1.5?Ö4 muscles with fasciculations 2. Prospective study 59 patients with suspected ALS (27 ALS, 32 mimics) Sensitivity 96% Specificity 84% Arts US med biol 2008 Arts Clin Neurophys 2012

45 Diagnosing ALS - revised El Escorial criteria

46 Diagnosing ALS - revised El Escorial criteria

47 "Fasciculations = denervation"?œawaji criteria US can detect fasciculations in 10-30% of the muscles that are EMG negative 1,2,3 US can increase diagnostic certainty by detecting subclinical involvement of EMG negative regions 4 US added to EMG: 5 5% of patients possible?^ probable/definite ALS 20% of patients probable?definite ALS 1 Walker Muscle Nerve Wenzel J Neuroimaging Reimers J Neurol Arts Clin Neurophys Misawa Neurology 2011

48 Fasciculations in ALS: screening of "unusual muscles" Temporalis muscle Tongue (submental muscles)

49 To conclude Muscle ultrasound is a good screening tool for NMD in children can be used to determine the optimal muscle biopsy site is better in detecting fasciculations than EMG (as an add-on tool to EMG): increases clinical diagnostic certainty in ALS

50 Thanks for your attention!