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Modern Rheumatology
Erschienen in: Modern Rheumatology 2/2008

01.04.2008 | Review Article

Limits and perspectives of ultrasound in the diagnosis and management of rheumatic diseases

verfasst von: Andrea Delle Sedie, Lucrezia Riente, Stefano Bombardieri

Erschienen in: Modern Rheumatology | Ausgabe 2/2008

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Abstract

Musculoskeletal sonography (MSUS) has played a growing role in the diagnosis and management of rheumatic diseases, enabling the imaging of synovitis, bone erosion, and cartilage damage in the early phase of arthritis. “Dynamic” evaluation of tendons and help in guiding needle positioning in interventional manoeuvres are some of the other reasons for its success. MSUS, particularly when coupled with power Doppler (PD) examination, has recently been shown to be an efficient tool for monitoring disease activity and progression in rheumatoid arthritis, spondyloarthritis, crystal-related arthropathy, and osteoarthritis, with general consensus on its interesting results. More specifically, the PD signal has proved to be a simple and promising tool for short-term monitoring of synovial vascularity changes induced by steroids or biological agents in RA patients. MSUS has some limits, because of the physical properties of US and the quality of the equipment; it is, moreover, an operator-related imaging technique, with few standardized protocols. Future goals should be standardization of the examining approach in grey scale and Doppler ultrasound (US), including use of new equipment (3D US), extensive use in other fields (i.e. connective tissue diseases and vasculitis), and possible new applications (e.g. thoracic US).
Literatur
1.
Kane D, Balint PV, Sturrock R, Grassi W. Musculoskeletal ultrasound—a state of the art review in rheumatology. Part 1: current controversies and issue in the development of musculoskeletal ultrasound in rheumatology. Rheumatology 2004;43:823–8.PubMedCrossRef
2.
Tynjala P, Honkanen V, Lahdenne P. Intra-articular steroids in radiologically confirmed tarsal and hip synovitism of juvenile idiopathic arthritis. Clin Exp Rheumatol 2004;22(5):643–8.PubMed
3.
Koski JM, Saarakkala SJ, Heikkinen JO, Hermunen HS. Use of air-steroid-saline mixture as contrast medium in greyscale ultrasound imaging: experimental study and practical applications in rheumatology. Clin Exp Rheumatol 2005;23:373–8.PubMed
4.
Filippucci E, Farina A, Carotti M, Salaffi F, Grassi W. Grey scale and power Doppler sonographic changes induced by intra-articular steroid injection treatment. Ann Rheum Dis 2004;63:740–3.PubMedCrossRef
5.
Grassi W, Filippucci E. Is power Doppler sonography the new frontier in therapy monitoring? Clin Exp Rheumatol 2003;21:424–8.PubMed
6.
Brown AK, Wakefield RJ, Conaghan PG, Karim Z, O’Connor PJ, Emery P. New approaches to imaging early inflammatory arthritis. Clin Exp Rheumatol 2004;22(5 Suppl 35):S18–25.PubMed
7.
Newman JS, Laing TJ, McCarthy CJ, Adler RS. Power Doppler sonography of synovitis: assessment of therapeutic response—preliminary observations. Radiology 1996;198:582–4.PubMed
8.
Stone M, Bergin D, Whelan B, Maher M, Murray J, McCarthy C. Power Doppler ultrasound assessment of rheumatoid hand synovitis. J Rheumatol 2001;28:1979–82.PubMed
9.
Iagnocco A, Cerioni A, Coari G, Ossandon A, Masciangelo R, Valesini G. Intra-articular methotrexate in the treatment of rheumatoid arthritis and psoriatic arthritis: a clinical and sonographic study. Clin Rheumatol 2006;25:159–63.PubMedCrossRef
10.
Ribbens C, André B, Marcelis S, Kaye O, Mathy L, Bonnet V et al. Rheumatoid hand joint synovitis: gray-scale and power Doppler US quantifications following anti-Tumor Necrosis Factor-α treatment: pilot study 1. Radiology 2003;229:562–9.PubMedCrossRef
11.
Taylor PC, Steuer A, Gruber J, Cosgrove DO, Blomley MJK, Marsters PA et al. Comparison of ultrasonographic assessment of synovitis and joint vascularity with radiographic evaluation in a randomized, placebo-controlled study of infliximab therapy in early rheumatoid arthritis. Arthritis Rheum 2004;50:1107–16.PubMedCrossRef
12.
Taylor PC, Steuer A, Gruber J, McClinton C, Cosgrove DO, Blomley MJ. Ultrasonographic and radiographic results from a two-year controlled trial of immediate or one-year-delayed addition of infliximab to ongoing methotrexate therapy in patients with erosive early rheumatoid arthritis. Arthritis Rheum 2006;54:47–53.PubMedCrossRef
13.
Takahashi A, Sato A, Yamadera Y, Takeda I, Kanno T, Ohguchi Y et al. Doppler sonographic evaluation of effect of treatment with infliximab (Remicade) for rheumatoid arthritis. Mod Rheumatol 2005;15(1):37–40.PubMedCrossRef
14.
Shio K, Homma F, Kanno Y, Yamadera Y, Ohguchi Y, Nishimaki T et al. Doppler sonographic comparative study on usefulness of synovial vascularity between knee and metacarpophalangeal joints for evaluation of articular inflammation in patients with rheumatoid arthritis treated by infliximab. Mod Rheumatol 2006;16(4):220–5.PubMedCrossRef
15.
Hau M, Kneitz C, Tony HP, Keberle M, Jahns R, Jenett M. High resolution ultrasound detects a decrease in pannus vascularisation of small finger joints in patients with rheumatoid arthritis receiving treatment with soluble tumour necrosis factor a receptor (etanercept). Ann Rheum Dis 2002;61:55–8.PubMedCrossRef
16.
Terslev L, Torp-Pedersen S, Qvistgaard E, Kristoffersen H, Rogind H, Danneskiold-Samsoe B et al. Effects of treatment with etanercept (Enbrel, TNRF:Fc) on rheumatoid arthritis evaluated by Doppler ultrasonography. Ann Rheum Dis 2003;62(2):178–81.PubMedCrossRef
17.
Fiocco U, Ferro F, Vezzù M, Cozzi L, Checchetto C, Sfriso P et al. Rheumatoid and psoriatic knee synovitis: clinical, grey scale, and power Doppler ultrasound assessment of the response to etanercept. Ann Rheum Dis 2005;64:899–905.PubMedCrossRef
18.
Iagnocco A, Perella C, Ceccarelli F, Tripodo E, Alessandri C, Magrini L et al. Ultrasonographic assessment of the response to Etanercept treatment in patients with rheumatoid arthritis. Reumatismo 2006;58(3):233–8.PubMed
19.
Filippucci E, Iagnocco A, Salaffi F, Cerioni A, Valesini G, Grassi W. Power Doppler sonography monitoring of synovial perfusion at wrist joint in rheumatoid patients treated with adalimumab. Ann Rheum Dis 2006;65:1433–7. PubMedCrossRef
20.
D’Agostino MA, Breban M, Said-Nahal R, Dougados M. Refractory inflammatory heel pain in spondyloarthropathy. A significant response to infliximab documented by ultrasound. Arthritis Rheum 2002;46:840–3.PubMedCrossRef
21.
Perez-Ruiz F, Martin I, Canteli B. Ultrasonographic Measurement of Tophi as an Outcome Measure for Chronic Gout. J Rheumatol 2007;34:1888–93.PubMed
22.
Iagnocco A, Filippucci E, Meenagh G, Delle Sedie A, Riente L, Bombardieri S et al. Ultrasound imaging for the rheumatologist. I. Ultrasound of the shoulder. Clin Exp Rheumatol 2006;24:6–11.PubMed
23.
Filippucci E, Iagnocco A, Meenagh G, Riente L, Delle Sedie A, Bombardieri S et al. Ultrasound imaging for the rheumatologist II. Ultrasound of the hand and wrist. Clin Exp Rheumatol 2006;24:118–22.PubMed
24.
Iagnocco A, Filippucci E, Meenagh G, Delle Sedie A, Riente L, Bombardieri S et al. Ultrasound imaging for the rheumatologist III. Ultrasound of the hip. Clin Exp Rheumatol 2006;24:229–32.PubMed
25.
Meenagh G, Iagnocco A, Filippucci E, Riente L, Delle Sedie A, Bombardieri S et al. Ultrasound imaging for the rheumatologist IV. Ultrasonography of the knee. Clin Exp Rheumatol 2006;24:357–60.PubMed
26.
Riente L, Delle Sedie A, Iagnocco A, Filippucci E, Meenagh G, Valesini G et al. Ultrasound imaging for the rheumatologist V. Ultrasonography of the ankle and foot. Clin Exp Rheumatol. 2006;24(5):493–8.PubMed
27.
Delle Sedie A, Riente L, Iagnocco A, Filippucci E, Meenagh G, Valesini G et al. Ultrasound imaging for the rheumatologist. VI. Ultrasonography of the elbow, sacroiliac, parasternal, and temporomandibular joints. Clin Exp Rheumatol 2006;24(6):617–21.PubMed
28.
Filippucci E, Iagnocco A, Meenagh G, Riente L, Delle Sedie A, Bombardieri S et al. Ultrasound imaging for the rheumatologist. Clin Exp Rheumatol 2006;24:1–5.PubMed
29.
Backhaus M, Kamradt T, Sandrock D, Loreck D, Fritz J, Wolf KJ et al. Arthritis of the finger joints: a comprehensive approach comparing conventional radiography, scintigraphy, ultrasound, and contrast-enhanced magnetic resonance imaging. Arthritis Rheum 1999;42:1232–45.PubMedCrossRef
30.
Meenagh G, Filippucci E, Iagnocco A, Delle Sedie A, Riente L, Bombardieri S et al. Ultrasound imaging for the rheumatologist VIII. Ultrasound imaging in osteoarthritis. Clin Exp Rheumatol 2007;25(2):172–5.PubMed
31.
Grassi W, Filippucci E, Farina A. Ultrasonography in osteoarthritis. Semin Arthritis Rheum 2005;34:19–23.PubMedCrossRef
32.
Filippucci E, Iagnocco A, Meenagh G, Riente L, Delle Sedie A, Bombardieri S et al. Ultrasound imaging for the rheumatologist VII. Ultrasound imaging in rheumatoid arthritis. Clin Exp Rheumatol 2007;25(1):5–10.PubMed
33.
Riente L, Delle Sedie A, Filippucci E, Iagnocco A, Meenagh G, Grassi W et al. Ultrasound imaging for the rheumatologist IX. Ultrasound imaging in spondyloarthritis. Clin Exp Rheumatol 2007;25(3):349–53.PubMed
34.
Delle Sedie A, Riente L, Filippucci E, Iagnocco A, Meenagh G, Grassi W et al. Ultrasound imaging for the rheumatologist X. Ultrasound imaging in crystal-related arthropathies. Clin Exp Rheumatol 2007;25(4):513–7.PubMed
35.
Grassi W, Filippucci E, Farina A, Cervini C. Sonographic imaging of tendons. Arthritis Rheum 2000;43:969–76.PubMedCrossRef
36.
Martinoli C, Bianchi S, Derchi LE. Tendon and nerve sonography. Radiol Clin North Am 1999;37:691–711.PubMedCrossRef
37.
Kane D, Grassi W, Sturrock R, Balint PV. Musculoskeletal ultrasound—a state of the art review in rheumatology. Part 2: clinical indications for musculoskeletal ultrasound in rheumatology. Rheumatology 2004;43:829–38.PubMedCrossRef
38.
El Miedany YM, Aty SA, Ashour S. Ultrasonography versus nerve conduction study in patients with carpal tunnel syndrome: substantive or complementary tests? Rheumatology 2004;43:887–95.PubMedCrossRef
39.
Klauser A, Frauscher F, Schirmer M. Value of contrast-enhanced power Doppler ultrasonography (US) of the metacarpophalangeal joints on rheumatoid arthritis. Eur Radiol 2004;14:545–6.PubMedCrossRef
40.
Gibbon WW, Wakefield RJ. Ultrasound in inflammatory disease. Radiol Clin North Am 1999;37:633–51.PubMedCrossRef
41.
Wakefield RJ, Brown AK, O’Connor PJ, Emery P. Power Doppler sonography: improving disease activity assessment in inflammatory musculoskeletal disease. Arthritis Rheum 2003;48:285–8.PubMedCrossRef
42.
Taggart A, Filippucci E, Wright G, Bell A, Cairns A, Meenagh G et al. Musculoskeletal ultrasound training in rheumatology: the Belfast experience. Rheumatology (Oxford) 2006;45:102–5.CrossRef
43.
Filippucci E, Unlu Z, Farina A, Grassi W. Sonographic training in rheumatology: a self teaching approach. Ann Rheum Dis 2003;62:565–7.PubMedCrossRef
44.
Koski JM, Saarakkala S, Helle M, Hakulinen U, Heikkinen JO, Balint P et al. Assessing the intra- and inter-reader reliability of dynamic ultrasound images in power Doppler ultrasonography. Ann Rheum Dis 2006;65:1658–60.PubMedCrossRef
45.
Scheel AK, Schmidt WA, Hermann KG, Bruyn GA, D’Agostino MA, Grassi W et al. Interobserver reliability of rheumatologists performing musculoskeletal ultrasonography: results from a EULAR “Train the trainers” course. Ann Rheum Dis 2005;64:1043–9.PubMedCrossRef
46.
Naredo E, Moller I, Moragues C, de Agustin JJ, Scheel AK, Grassi W et al. Interobserver reliability in musculoskeletal ultrasonography: results from a “Teach the Teachers” rheumatologist course. Ann Rheum Dis 2006;65:14–9.PubMedCrossRef
47.
D’Agostino MA, Wakefield RJ, Filippucci E et al. Intra- and inter-observer reliability of ultrasonography for detecting and scoring synovitis in rheumatoid arthritis: a report of a EULAR ESCISIT Task Force. Ann Rheum Dis 2005;64 Suppl III:62.
48.
Fiocco U, Ferro F, Cozzi L, Vezzu M, Sfriso P, Checchetto C et al. Contrast medium in power Doppler ultrasound for assessment of synovial vascularity: comparison with arthroscopy. J Rheumatol 2003;30:2170–6.PubMed
49.
Szkudlarek M, Court-Payen M, Jacobsen S, Klarlund M, Thomsen HS, Østergaard M. Interobserver agreement in ultrasonography of the finger and toe joints in rheumatoid arthritis. Arthritis Rheum 2003;48:955–62.PubMedCrossRef
50.
Wakefield RJ, Balint PV, Szkudlarek M, Filippucci E, Backhaus M, D’Agostino MA et al. Musculoskeletal Ultrasound Including Definitions for Ultrasonographic Pathology. J Rheumatol 2005;32:2485–7.PubMed
51.
Keen HI, Lavie F, Wakefield RJ, D’Agostino MA, Berner Hammer H, Hensor EM et al. The development of a preliminary ultrasonographic scoring system for features of hand osteoarthritis. Ann rheum Dis 2007 Aug 17; [Epub ahead of print].
52.
Wakefield RJ, D’Agostino MA, Iagnocco A, Filippucci E, Backhaus M, Scheel AK et al. The OMERACT Ultrasound Group: Status of Current Activities and Research Directions. J Rheumatol 2007;34:848–51.PubMed
53.
Naredo E, Gamero F, Bonilla G, Uson J, Carmona L, Laffon A. Ultrasonographic assessment of inflammatory activity in rheumatoid arthritis: comparison of extended versus reduced joint evaluation. Clin Exp Rheumatol 2005;23:881–4.PubMed
54.
Iagnocco A, Ossandon A, Coari G, Conti F, Priori R, Alessandri C et al. Wrist joint involvement in systemic lupus erythematosus. An ultrasonographic study. Clin Exp Rheumatol 2004;22:621–4.PubMed
55.
Wright S, Filippucci E, Grassi W, Grey A, Bell A. Hand arthritis in systemic lupus erythematosus: an ultrasound pictorial essay. Lupus 2006;15:501–6.PubMedCrossRef
56.
Iagnocco A, Coari G, Palombi G, Valesini G. Knee joint synovitis in Sjogren’s syndrome. Sonographic study. Scand J Rheumatol 2002;31:291–5.PubMedCrossRef
57.
Riente L, Baldini C, Delle Sedie A, Possemato N, Tavoni A. Ultrasound evaluation of early primary Sjogren’s syndrome. Ann Rheum Dis 2006;65(Suppl II):582 [abstract].
58.
Reimers CD, Fleckenstein JL, Witt TN, Muller-Felber W, Pongratz DE. Muscular ultrasound in idiopathic inflammatory myopathies of adults. J Neurol Sci 1993;116:82–93.PubMed
59.
Weber MA, Jappe U, Essig M, Krix M, Ittrich C, Huttner C et al. Contrast-enhanced ultrasound in dermatomyositis and polymyositis. J Neurol 2006;253:1625–32.PubMedCrossRef
60.
Weber MA, Krix M, Jappe U, Huttner HB, Hartmann M, Meyding-Lamade U et al. Pathologic skeletal muscle perfusion in patients with myositis: detection with quantitative contrast-enhanced US – initial results. Radiology 2006;238:640–9.PubMedCrossRef
61.
Schmidt WA, Kraft HE, Vorpahl K, Volker L, Gromnica-Ihle EJ. Color duplex ultrasonography in the diagnosis of temporal arteritis. N Eng J Med 1997;337:1336–42.CrossRef
62.
Schmidt WA, Gromnica-Ihle EJ. Incidence of temporal arteritis in patients with polymyalgia rheumatica: a prospective study using colour Doppler ultrasonography of the temporal arteries. Rheumatology 2002;41:46–52.PubMedCrossRef
63.
Seitz WS, Kline HJ, McIlroy MB. Quantitative assessment of peripheral arterial obstruction in Raynaud’s phenomenon: development of a predictive model of obstructive arterial cross-sectional area and validation with a Doppler blood flow study. Angiology 2000;51:985–98.PubMedCrossRef
64.
Cheng KS, Tiwari A, Boutin A, Denton CP, Black CM, Morris R et al. Differentiation of primary and secondary Raynaud’s disease by carotid arterial stiffness. Eur J Vasc Endovasc Surg 2003;25:336–41.PubMedCrossRef
65.
Moore TL, Lunt M, McManus B, Anderson ME, Herrick AL. Seventeen-point dermal ultrasound scoring system-a reliable measure of skin thickness in patients with systemic sclerosis. Rheumatology 2003;42:1559–63.PubMedCrossRef
66.
Hashikabe M, Ohtsuka T, Yamazaki S. Quantitative echographic analysis of photochemotherapy on systemic sclerosis skin. Arch Dermatol Res 2005;296:522–7.PubMedCrossRef
67.
Akesson A, Hesselstrand R, Scheja A, Wildt M. Longitudinal development of skin involvement and reliability of high frequency ultrasound in systemic sclerosis. Ann Rheum Dis 2004;63:791–6.PubMedCrossRef
68.
Scheja A, Akesson A. Comparison of high frequency (20 MHz) ultrasound and palpation for the assessment of skin involvement in systemic sclerosis (scleroderma). Clin Exp Rheumatol 1997;15(3):283–8.PubMed
69.
Lichtenstein DA. Ultrasound in the management of thoracic disease. Crit Care Med 2007;35[Suppl.]:S250–61.CrossRef
70.
Picano E, Frassi F, Agricola E, Gligorova S, Gargani L, Mottola G. Ultrasound lung comets: a clinically useful sign of extravascular lung water. J Am Soc Echocardiogr 2006;19:356–63.PubMedCrossRef
71.
Doveri M, Frassi F, Consensi A, Vesprini E, Gargani L, Tafuri M et al. Le comete ultrasoniche polmonari: un nuovo segno ecografico di fibrosi polmonare nella sclerodermia. Reumatismo 2007;59(numero speciale 2):12.
72.
Downey DB, Fenster A, Williams JC. Clinical utility of three-dimensional US. Radiographics 2000;20:559–71.PubMed
73.
Strunk J, Lange U. Three-dimensional power Doppler sonographic visualization of synovial angiogenesis in rheumatoid arthritis. J Rheumatol 2004;31:1004–6.PubMed
74.
Albrecht K, Muller-Ladner U, Strunk J. Quantification of synovial perfusion in rheumatoid arthritis using Doppler ultrasonography. Clin Exp Rheumatol 2007;25:630–8.PubMed
Metadaten
Titel
Limits and perspectives of ultrasound in the diagnosis and management of rheumatic diseases
verfasst von
Andrea Delle Sedie
Lucrezia Riente
Stefano Bombardieri
Publikationsdatum
01.04.2008
Verlag
Springer Japan
Erschienen in
Modern Rheumatology / Ausgabe 2/2008
Print ISSN: 1439-7595
Elektronische ISSN: 1439-7609
DOI
https://doi.org/10.1007/s10165-008-0046-z

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