Invited Commentary

Abstract

HomeRadioGraphicsVol. 30, No. 1 PreviousNext Free AccessInvited CommentaryMichael A. BrunoMichael A. BrunoAuthor AffiliationsDepartment of Radiology, Penn State College of Medicine, Milton S. Hershey Medical Center Hershey, PennsylvaniaMichael A. BrunoPublished Online:Jan 1 2010https://doi.org/10.1148/radiographics.30.1.0300163MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked InEmail I am delighted to have an opportunity to comment on the excellent article by Narváez et al (1) in this issue of RadioGraphics. The authors present a comprehensive review of the MR imaging findings in patients with early manifestations of rheumatoid arthritis, emphasizing the key pathologic features that are present in the early onset of the disease, a discrete and important time interval when initiation of appropriately aggressive therapy is of the utmost importance but the diagnosis is often quite difficult to establish. The article is well written and marvelously illustrated, and the authors appropriately emphasize the urgency of identifying those patients who would benefit from early initiation of treatment with biologic agents (anti-tumor necrosis factor α drugs such as etanercept, infliximab, and rituximab), steroids, or disease-modifying antirheumatic drugs such as methotrexate.For more than 50 years, imaging of patients with rheumatoid arthritis has consisted almost entirely of conventional radiography and thus has had very limited impact beyond helping to establish the initial diagnosis, which was often not made until significant irreversible joint damage had already occurred. In recent years, however, the advanced imaging of patients with rheumatoid arthritis with cross-sectional imaging methods such as MR imaging and US has become much more important in the initial diagnosis and ongoing management in this large patient population. As Narváez et al (1) point out, the role of imaging may be of particular value in patients in whom the diagnosis of rheumatoid arthritis is merely suspected, or in those showing only the earliest, and somewhat ambiguous, manifestations of disease. This change in the role of imaging from a peripheral to a central one in patients with rheumatoid arthritis has been driven by several factors. Foremost is the availability of interventions that can dramatically alter the course of the disease and substantially reduce or even prevent joint destruction if applied early enough and in a sufficiently aggressive way. This so-called early aggressive therapy approach to early rheumatoid arthritis was first advocated by leading rheumatologists such as Dr Theodore Pincus (now at the New York University School of Medicine), Dr Paul Emery (University of Leeds, England), and others nearly 2 decades ago (2), but has only recently become the new standard of care in rheumatoid arthritis. Second is the fact that there is currently no reliable physical examination or laboratory assessment that can help establish the diagnosis in early rheumatoid arthritis with sufficient accuracy and speed to allow the initiation of therapy within what is probably a very narrow window of opportunity for most patients. As Narváez et al illustrate, MR imaging can help fill this diagnostic void by helping identify characteristic, reliable evidence of early disease long before it would be possible with conventional means. Because as many as 1% of the world’s population (tens of millions of people) are afflicted with rheumatoid arthritis and the incidence of new cases is reported to be as many as four per 10,000 adults per year worldwide (3), the impact of this type of accelerated diagnosis is quite substantial. Consequently, radiologists now have a much greater opportunity to have a positive impact on these patients, and now, more than ever before, it is incumbent upon all radiologists to familiarize themselves with this topic. The article by Narváez et al (1) does our specialty a great service in this regard, and is thus a timely and important contribution to the radiology literature.Currently, despite intensive work in this area by expert panels of rheumatologists and radiologists, most notably the OMERACT group, a consensus on diagnostic criteria for MR imaging (and US) in early rheumatoid arthritis has not yet been reached. The roles of MR imaging, US, and perhaps even 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET) do indeed overlap in this patient population; however, MR imaging may be of particular value in that it can uniquely help detect potentially reversible inflammatory “preerosive” changes, which manifest as focal areas of discrete signal intensity change and are an apparent precursor—or at least a potential precursor—for the development of characteristic erosions in rheumatoid arthritis. Østergaard et al (4) were among the first to suggest that these early changes in bone marrow signal intensity, seen with fluid-sensitive MR imaging sequences at the joint margins in patients with rheumatoid arthritis, appear to represent a type of preerosive osteitis, an inflammatory rather than an erosive process, occurring at the typical locations of rheumatoid erosions. This hypothesis was ultimately proved histologically by the same research group (5). Narváez et al (1) cite this literature and note that these lesions are indeed a manifestation of an inflammatory process, but adhere to the common practice of referring to them as localized “bone marrow edema,” after the OMERACT nomenclature. The reader should understand, however, that the word edema in this context refers to a focus of inflammation in the subchondral bone, which, if unchecked, will evolve into a characteristic erosion of rheumatoid arthritis.The excellent article by Narváez et al (1) focuses on the use of MR imaging primarily in initial triage among patients who present with early manifestations of rheumatoid arthritis to allow the rapid initiation of treatment, which is a particularly strong “niche” for MR imaging. However, MR imaging, as well as other advanced imaging methods such as US, has also been shown to play a significant role in ongoing therapeutic management in these patients. Narváez et al in fact mention this topic in the very last sentence of their article, but I feel that the issue is important enough to warrant further discussion here.Because physical examination, radiography, and laboratory methods are quite limited in helping determine when the level of treatment is adequate, answering this critical clinical question is increasingly becoming the job of the radiologist. Indeed, with a much stronger armamentarium than ever before, today’s rheumatologist is now under much greater pressure to verify and justify treatment decisions, such as what medications and classes of medications to use at what dosage and with what frequency, whether to use a particular medication alone or in combination with others, and so on. Rapid and accurate feedback as to the effectiveness of the chosen regimen is much more urgently needed by clinicians than ever before, if joint damage and long-term morbidity are to be avoided. MR imaging, US (especially power Doppler US), and 18F FDG PET have all been shown to have tremendous efficacy in providing just this type of rapid and meaningful data on the clinical response to any chosen treatment (6–8). Each imaging method has its own strengths and drawbacks, and, in fact, for ongoing monitoring of therapy, semiquantitative power Doppler US assessment of synovitis in treated rheumatoid arthritis may well be the preferred approach. Indeed, power Doppler US can reproducibly help detect small changes in the severity of synovitis, thereby allowing rapid modification of therapy when needed (6,9,10). With MR imaging, a decrease in the degree of contrast enhancement and the quantitative assessment of the enhanced (inflamed) synovial volume with use of manual or semiautomated methods have been shown to have great utility, as Narváez et al (1) point out.Most rheumatologists now believe that treatment failure is more likely if therapy is not guided by some objective means of assessment, and that physical examination, patients’ subjective impressions of their symptom severity, and conventional radiography are, individually or in combination, simply not sufficient to the task. In addition, because aggressive treatment options are costly and carry their own significant risks, there is even greater pressure to objectively document their ongoing effectiveness so as to justify both the risk and the expense to third-party payors. As I mentioned earlier, this has created for radiologists both a golden opportunity to have a positive impact on a huge population of patients—those millions of persons currently living with rheumatoid arthritis (including those patients with new, as yet undiagnosed disease)—and a significant new burden of responsibility to ensure that the treatment needs of each rheumatoid arthritis patient are met.Future research in this field should emphasize a greater degree of standardization of MR imaging techniques and a greater degree of consensus regarding diagnostic criteria. For example, a broadly accepted MR imaging scoring system and a better consensus regarding which outcomes measures are most useful would be of great benefit in the acceleration of clinical trials. The development of new automated methods for quantification of MR imaging findings might make the the clinical use of image-based quantitative analysis in rheumatoid arthritis feasible. Novel MR imaging contrast agents such as injectible ultrasmall superparamagnetic iron oxide particles, the use of which is currently under intense investigation (11), may further increase the value of MR imaging in the management of cases of rheumatoid arthritis. Finally, further research should lead to a greater consensus regarding the respective roles of MR imaging and US, as well as other advanced imaging modalities, in this patient population.References1 Narváez JA, Narváez J, De Lama E, De Albert MMR imaging of early rheumatoid arthritis. Radio-Graphics 2009;30(1):143–163; discussion 163–165. Google Scholar2 Pincus TThe case for early intervention in rheumatoid arthritis. J Autoimmun 1992;5(suppl A): 209–226. Crossref, Medline, Google Scholar3 Kaipiainen-Seppänen O, Aho K, Isomäki H, Laakso MIncidence of rheumatoid arthritis in Finland during 1980–1990. Ann Rheum Dis 1996;55(9): 608–661. Crossref, Medline, Google Scholar4 Østergaard M, Hansen M, Stoltenberg Met al.New radiographic bone erosions in the wrists of patients with rheumatoid arthritis are detectable with magnetic resonance imaging a median of two years earlier. Arthritis Rheum 2003;48(8):2128–2131. Crossref, Medline, Google Scholar5 McQueen FM, Gao A, Østergaard Met al.High-grade MRI bone oedema is common within the surgical field in rheumatoid arthritis patients undergoing joint replacement and is associated with osteitis in subchondral bone. Ann Rheum Dis 2007;66(12): 1581–1587. Crossref, Medline, Google Scholar6 Bruno M, Wakefield R. Ultrasound evaluation of rheumatoid arthritis. In: Bruno M, Mosher T, Gold G, eds. Arthritis in color: advanced imaging of arthritis. Philadelphia, Pa: Saunders-Elsevier, 2009; 100–118. Crossref, Google Scholar7 Østergaard, Hansen M, Stoltenberg Met al.Magnetic resonance imaging-determined synovial membrane volume as a marker of disease activity and a predictor of progressive joint destruction in the wrists of patients with rheumatoid arthritis. Arthritis Rheum 1999;42(5):918–929. Crossref, Medline, Google Scholar8 Ribbens C, Hustinx R. Nuclear (scintigraphic) methods and FDG-PET in rheumatoid arthritis and osteoarthritis. In: Bruno M, Mosher T, Gold G, eds. Arthritis in color: advanced imaging of arthritis. Philadelphia, Pa: Saunders-Elsevier, 2009; 145–147. Crossref, Google Scholar9 Wakefield RJ, O’Connor PJ, Conaghan PGet al.Finger tendon disease in untreated early rheumatoid arthritis: a comparison of ultrasound and magnetic resonance imaging. Arthritis Rheum 2007;57(7): 1158–1164. Crossref, Medline, Google Scholar10 Backhaus M, Kamradt T, Sandrock Det al.Arthritis of the finger joints: a comprehensive approach comparing conventional radiography, scintigraphy, ultrasound, and contrast-enhanced magnetic resonance imaging. Arthritis Rheum 1999;42(6):1232–1245. Crossref, Medline, Google Scholar11 Simon GH, von Vopelius-Feldt J, Wendland MFet al.MRI of arthritis: comparison of ultrasmall super-paramagnetic iron oxide vs. Gd-DTPA. J Magn Reson Imaging 2006;23(5):720–727. 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