Magnetic resonance imaging (MRI) is a noninvasive diagnostic technique that produces computerized images of internal body structures and tissues. MRI does not use ionizing radiation and has been used for diagnostic imaging for the past 30 years. This document addresses the clinical value of conventional MRI and low field MRI use in rheumatologic and orthopedic conditions.

Investigational and Not Medically Necessary:

Magnetic resonance imaging (MRI) (high, intermediate or low field) is considered investigational and not medically necessary to screen, diagnose, monitor disease activity, or monitor response to medication for rheumatoid arthritis or other rheumatologic conditions.   

Low field magnetic resonance imaging (MRI ) (less than or equal to 0.2T [Tesla] magnet strength) is considered investigational and not medically necessary for all orthopedic applications, including but not limited to when used to evaluate symptoms arising from or need for surgery to the knee, shoulder, spine, foot.

Use of MRI in Rheumatologic Disease:

Rheumatoid Arthritis (RA), a chronic disabling condition, often presents with signs and symptoms of inflammation such as joint pain which leads to structural damage that contributes to loss of function and disability.  Conventional radiography (CR) has a long history of use in the practice of rheumatology.  CR parameters have been standardized and have been used extensively in the rheumatology literature and in guideline development for rheumatology.  When used in clinical drug trials of antirheumatic drugs, CR demonstrated a correlation of response to the drug therapy.  Based on the performance of CR imaging in these trials, and the use of these measures in the rheumatology literature, many rheumatologists use radiographs to stage an individual at the onset of disease as well as to monitor response to therapy.  However, the 2008 recommendation from the American College of Rheumatology (Saag, et al., 2008) for the use of nonbiologic and biologic disease-modifying antirheumatic drugs in rheumatoid arthritis reinforces the importance of clinical disease activity scores to guide treatment decisions and does not describe a significant role for the use of CR, let alone MRI, for treatment decisions for individuals with RA.

Use of MRI in rheumatologic disease has been in part driven by increased access to in-office low-field MRI machines despite the lack of evidence of benefit of even conventional high-field MRI technology in the management of individuals with RA.  The clinical studies of MRI imaging for RA have been problematic in that image acquisition and interpretation vary significantly.  For example, magnet strength, the use of dedicated coils and the choice of MRI sequences determines the acquisition of the image which in turn influences the image quality and ultimately interpretation.  Currently, attempts to standardize image acquisition, terminology and quantification are being studied by an international panel of experts at Outcome Measures in Rheumatoid Arthritis consensus conferences.  This lack of standardization contributes to the difficulty in assessing studies regarding the use of this technique.  Finally, there are no studies in the medical literature which demonstrate the use of low field peripheral or conventional MRI imaging results in improved outcomes for any rheumatologic condition.

In 2006, the American College of Rheumatology published a report on extremity MRI use in rheumatology which reviewed the existing body of literature and made the following summary statements:

"The benefits of low-field strength extremity MRI for the diagnosis and management of rheumatoid arthritis are still being elucidated. Our review raises the following issues:

1. The literature assessing the utility of peripheral joint MRI has used high-field, not low-field extremity MRI; therefore, actual sensitivity, specificity, and predictive value of the low-field scanners available for the practicing rheumatologists are not known.
2. The high sensitivity of MRI for the detection of erosions may be at least partially offset by a lack of specificity; a significant false-positive rate is suggested by the finding that many "erosions" detected by MRI do not progress to radiographic erosions over many years. The one published study evaluating the predictive value of a single MRI erosion showed that only 26% of these became radiographically evident erosions at 2 years.
3. The published literature on the importance of erosions in RA and their correlation with functional decline is based on radiographic studies, not MRI series, and the predictive value of erosions detected by MRI may be significantly less than is assumed (especially for those erosions that are never identified by radiography even after several years).
4. Ideally, scanning would be performed only when the results would provide information that is otherwise unavailable and would affect management; for example, the patient and clinician are unlikely to be helped by peripheral MRI if the patient is receiving maximal therapy, with no evidence of active disease, or if clinical disease activity is significant and treatment change would be indicated regardless of the MRI findings.
5. The marginal benefit of low-field extremity MRI above and beyond standard measures of disease activity and severity (including history, physical examination, selective laboratory testing, and radiography of the hands and wrists) has not been rigorously evaluated in studies published to date. In fact, at least one study suggests that high-field MRI is no better than bilateral hand radiography in detecting progression of joint damage over 2 years, presumably because more joints are surveyed by radiography.
6. Imaging may be helpful in select patients when the history, physical examination, routine laboratory testing, and standard radiographic imaging are inadequate to enable a rational decision regarding management; however, the indications for such imaging remain uncertain. A negative result in a patient with mild RA disease activity might provide confidence for use of less aggressive treatment, but to date there have been no studies to validate this hypothesis using low-field extremity MRI.
7. There is currently no consensus regarding when high-field MRI should be ordered for the diagnosis and management of RA. Due to the limitations of study design and the limited number of studies, it is even more difficult to establish clinical indications for low-field extremity scanning."

In summary, MRI is a sensitive method of detecting abnormalities in individuals with rheumatologic disease, but the increased numbers of lesions detected have not been proven to drive meaningful decisions (initiation, dosing, continuation or discontinuation of treatment) in these conditions which result in clinically superior outcomes.  Further research is required to show that use of MRI can improve the outcome in individuals with rheumatologic disease.

Hetland and colleagues published the 2- and 5-year results of the CIMESTRA trial in two different publications.  This randomized, placebo-controlled, double-blind study involved 130 subjects with early RA being treated with disease modifying drugs (DMARDs) and intra-articular glucocorticoids with a focus on maximal inflammatory control.  Subjects were evaluated at baseline with an MRI of the wrist or MRI of the wrist and metacarpalphalageal (MCP) joints in addition to radiographs of the wrists, hands and feet, and group of biomarkers for inflammatory disease status including anti-cyclic citrullinated peptide (anti-CCP) and total Sharpe-van der Hejide Score (TSS) (Hetland, 2009).  In the first report presenting the results at 2 years the findings included that MRI erosion, MRI synovitis, and MRI bone marrow edema scores at baseline were significantly associated with radiographic progression at 2 years and were a significant individual predictive factor.  However, after multiple linear regression analysis only MRI bone marrow edema scores remained as a significant predictor of progression in this population of subjects.  The second report follows this same population through 5 years of treatment (Hetland, 2010). This report found that MRI bone marrow edema score was still a strong independent predictor of RA progression, but that it was only "borderline significant" (p=0.09) in multiple linear regression analysis, far behind two other measures, anti-CCP (p=0.002) and TSS (p=0.006).  The authors point out several possible limitations of their study, including a high number of subjects with erosive disease at baseline that may have impacted the predictive power of the study, and that several different MRI units with varying tesla strength were used across the study centers (0.2T to 1.5T).  This may have influenced the quality of the MRI images reviewed and presented a source of uncontrolled variation in MRI scores.  In conclusion, the findings of these studies show that MRI bone marrow edema scores may be a useful predictor of RA progression, but other measures together provided better predictive value.  Further study is warranted to determine if the MRI scores can inform clinical care and improve patient outcomes (clinical utility) of individuals with RA.

Orthopedic Use of Low Field less than or equal to 0.2T) MRI

Similar to the increased use of MRI for rheumatologic disease, the availability of office-based low field MRI imaging systems has resulted in increased use of this technology in various orthopedic applications.  The specific role of low field as compared to conventional high field MRI remains unclear.  Review of the literature regarding low field MRI technology for orthopedic applications reveals a lack of adequately sized, well designed clinical studies.  There are several concerns with low-field MRI.  Magnet strength is critical to image clarity as well as acquisition time.  Less powerful magnets produce lower signal to noise ratios which results in lower quality images.  A recent review (Ghazinoor, 2008) concludes that "there is no question that high field MRI provides better quality images than low-field MRI; however, this does not necessarily translate into greater diagnostic power."  Review of the literature shows that these lower quality images have not been proven to provide equal diagnostic accuracy in adequately sized, properly controlled, randomized prospective trials. 

Low-Field MRI of the Shoulder

Two small studies (Tung, 2000; Magee, 2003) compared high field and low field MRI diagnostic capabilities for glenoid superior labral anteroposterior (SLAP) tears of the shoulder, and another small study (Rand, 1999) compared high field and low field MRI diagnostic capabilities for meniscal tears.  The Magee study reported on 40 subjects with suspected shoulder abnormalities who underwent both high and low field MRI.  In 9 of these 40, the high field MRI altered the diagnosis regarding tendon or labral tears.  All of these results were confirmed by arthroscopy.  The Tung study compared the sensitivity, specificity and accuracy of these two MRI techniques regarding shoulder abnormalities and found high field MRI superior.  The Rand study addressed the use of these imaging modalities in meniscal lesions and found discordant results in 4 of 25 cases.

There are two publications regarding use of 0.2T MRI in the shoulder authored by the same group (Shellock, 2001; Zlatkin, 2004).  The 2001 study was a retrospective review using surgical findings as a gold standard.  There was no discussion of use of MRI to support decisions not to have surgical intervention.  The low-field MRIs were performed at a single institution and were interpreted by three different radiologists, however inter-rater reliability was not reported.  There were three false negative examinations for partial thickness rotator cuff tear.  The results were compared to historical controls and the authors noted "The relationship between image quality and magnetic field strength has created a strong bias in favor of the use of high field systems."  If these results are applied to a pre-operative population, the failure to detect clinically significant lesions could result in inappropriate decisions to treat conservatively or expose individuals to unnecessary diagnostic surgery.  The 2004 study was also retrospective, and also did not compare low-field results to conventional MRI.  Again surgical findings were used as the gold standard.  There was poor negative predictive value for both rotator cuff tears (68%) and labral tears (82%).  Neither of these studies provides evidence that the results of low-field images are useful in the management of individuals with suspected shoulder injury.

Low Field MRI of the Knee

The literature addressing the use of low-field MRI for the evaluation of knee conditions with 0.2 T magnet strength devices is sparse.  Most of the studies published on this issue exceed ten years of age and involve small sample sizes (Franklin, 1997; Kinnunen, 1994; Kladny, 1995).  Two more recent studies by Riel (1999) and Cotten (2000) are still not particularly current, but do provide interesting data.  Riel and colleagues describe a prospective cohort study of 244 subjects who underwent 0.2T low-field MRI followed by arthroscopy within 48 hours.  The sensitivity, specificity and accuracy of low-field MRI for lateral meniscus, medical meniscus, posterior cruciate ligament, anterior cruciate ligament, and articular cartilage lesions were reported.  However, this data is not presented in contrast with data from full-field MRI scans.  Positive predictive value (PPV) and negative predictive value (NPV) data are also not available.  Cotten and others provide data comparing the results of 90 subjects with knee derangement who underwent scanning with both 0.2T and 1.5T MRI machines, followed by arthroscopy.  This study reports the sensitivity, specificity and accuracy of low-field MRI compared to full-field MRI for medial meniscus, lateral meniscus, and anterior cruciate ligament.  As with the Reil study PPV and NPV are not reported.  As with the literature regarding use in the shoulder, there is no randomization to intervene or not based on the results of the low-field images nor is there information regarding follow-up of individuals managed conservatively (without surgery).

Other Orthopedic Uses of Low Field MRI

A study by Nikken et al. (2005) assessed the use of low-field MRI in accessing acute trauma.  The study included 500 subjects with trauma to a variety of sites and compared standard films to low field MRI.  There was no comparison to high field MRI.  The study reported on cost savings, quality of life and expediting diagnostic work up.  No differences were noted for injuries of the wrist, or ankle. 

In summary, these studies convincingly document that image quality in high field MRI is superior to image quality in low field MRI.  The clinical studies demonstrate variability in the accuracy of the images at diagnosing lesions, generally involve small numbers of participants, lack randomization, and are often supported by the MRI manufacturers.  These studies do not show that the lower quality low-field MRI images are useful for making treatment decisions for individuals with suspected orthopedic injury.  Given the ready availability of conventional MRI, use of low-field technology is not supported for use in evaluation of the knee, shoulder or other anatomic sites.  Further study is warranted.

Magnetic Resonance Imaging (MRI) systems are available in different configurations and field strength.  The configuration refers to the design of the magnet.  The most common is the cylinder design, where the individual is enclosed in a cylinder tube for the imaging.  Other types of configurations are the open MRI, which uses a C arm configuration and the individual is not enclosed, but is positioned on a platform for the imaging.  Another type is the extremity only configuration, where the affected extremity is placed within the magnet area.  The configurations can be either high, mid or low field magnetic strength.

Recently, low field strength MRI equipment has become available and is designed to be used in the physician office, primarily for extremity imaging.  The use of low field strength extremity MRI for orthopedic and rheumatologic conditions is proposed for diagnosis and monitoring of disease or injury.  In the treatment of rheumatoid arthritis (RA), it has been proposed for use in staging and monitoring disease progression as well as the response to medication.  Orthopedic applications are primarily for diagnosing injuries to the extremities.

The proposed advantage of low field MRI configuration is the equipment is small and safe enough to be used in the office setting.  The disadvantage is this smaller equipment also has a smaller size magnetic field which contributes to limited image acquisition techniques and limited image resolution resulting in variance in interpretation.  Once the imaging and interpretation variances are resolved, low field MRI may be a useful diagnostic modality.

Image resolution: Refers to the detail an image can hold. The term is most often used in relation to digital images, but is also used to describe how grainy a "film-based" image is; higher resolution means more image detail is captured; for magnetic resonance imagining, the stronger the magnetic field, the stronger the amount of radio signals which can be elicited from the body's atoms and therefore the higher the quality of MRI images.

Low field magnetic resonance imaging: The strength of a magnetic field is measured in Tesla or Gauss Units; low-field MRI utilizes a magnetic field equal to or less than 0.2 Tesla (2,000 Gauss). 

The following codes for treatments and procedures applicable to this document are included below for informational purposes.  Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy.  Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member. 

When Services are Investigational and Not Medically Necessary:
For the procedure and diagnosis codes listed below, or when the code describes a procedure indicated in the Position Statement section as investigational and not medically necessary.

When Services are also Investigational and Not Medically Necessary:

Future ICD-10 coding (effective 10/01/2013)
A draft of ICD-10 Coding related to this document, as it might look today, is available for reference and comments at: Appendix 1: Future ICD-10 coding

Peer Reviewed Publications:

1. Benton N, Stewart N, J Crabbe, et al. MRI of the wrist in early rheumatoid arthritis can be used to predict functional outcome at 6 years. Ann Rheum Dis. 2004; 63:555–561.
2. Bird P, Ejbjerg B, McQueen F, et al. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 5: An international multicenter reliability study using computerized MRI erosion volume measurements. J Rheumatol. 2003; 30(6):1380-1384.
3. Bird P, Kirkham B, Portek I, et al. Documenting damage progression in a two-year longitudinal study of rheumatoid arthritis patients with established disease (the DAMAGE study cohort): is there an advantage in the use of magnetic resonance imaging compared with plain radiography? Arthritis Rheum. 2004; 50:1383–1389.
4. Chen TS, JV Crues 3rd, Ali M, Troum OM. Magnetic resonance imaging is more sensitive than radiographs in detecting change in size of erosions in rheumatoid arthritis. J Rheumatol. 2006; 33(10):1957-1967.
5. Conaghan PG, Ejbjerg B, Lassere M, et al. A multireader reliability study comparing conventional high-field magnetic resonance imaging with extremity low-field MRI in rheumatoid arthritis. J Rheumatol. 2007; 34(4):854-856.
6. Cotten A, Delfaut E, Demondion X, et al. MR imaging of the knee at 0.2 and 1.5 T: correlation with surgery. AJR Am J Roentgenol. 2000; 174(4):1093-1097.
7. Ejbjerg BJ, Narvestad E, Jacobsen S, et al. Optimised, low cost, low field dedicated extremity MRI is highly specific and sensitive for synovitis and bone erosions in rheumatoid arthritis wrist and finger joints: comparison with conventional high field MRI and radiography. Ann Rheum Dis, 2005; 64(9):1280-1287.
8. Ejbjerg J, Vestergaard A, Jacobsen S, et al. The smallest detectable difference and sensitivity to change of magnetic resonance imaging and radiographic scoring of structural joint damage in rheumatoid arthritis finger, wrist, and toe joints: a comparison of the OMERACT rheumatoid arthritis magnetic resonance imaging score applied to different joint combinations and the Sharp/van der Heijde radiographic score. Arthritis Rheum 2005; 52(8):2300-2306.
9. Forslind K, Johanson A, Larsson EM, et al. Magnetic resonance imaging of the fifth metatarsophalangeal joint compared with conventional radiography in patients with early rheumatoid arthritis. Scand J Rheumatol. 2003; 32(3):131-137.
10. Franklin PD, Lemon RA, Barden HS. Accuracy of imaging the menisci on an in-office, dedicated, magnetic resonance imaging extremity system. Am J Sports Med. 1997; 25(3):382-388.
11. Freeston JE, Conaghan PG, Dass S, et al. Does extremity-MRI improve erosion detection in severely damaged joints? A study of long-standing rheumatoid arthritis using three imaging modalities. Ann Rheum Dis. 2007; 66(11):1538-1540.
12. Ghazinoor S, Crues JV 3rd, Crowley C. Low-field musculoskeletal MRI. J Magn Reson Imaging. 2007; 25(2):234-244.
13. Graham TB, Laor T, Dardzinski BJ. Quantitative magnetic resonance imaging of the hands and wrists of children with juvenile rheumatoid arthritis. J Rheumatol. 2005; 32(9):1811-1820.
14. Hetland ML, Ejbjerg B, Horslev-Petersen K, et al.; CIMESTRA study group. MRI bone edema is the strongest predictor of subsequent radiographic progression in early rheumatoid arthritis. Results from a 2-year randomised controlled trial (CIMESTRA). Ann Rheum Dis. 2009; 68(3):384-390.
15. Hetland ML, Stengaard-Pedersen K, Junker P, et al.; CIMESTRA study group. Radiographic progression and remission rates in early rheumatoid arthritis - MRI bone oedema and anti-CCP predicted radiographic progression in the 5-year extension of the double-blind randomised CIMESTRA trial. Ann Rheum Dis. 2010; 69(10):1789-1795.
16. Jimenez-Boj E, Nöbauer-Huhmann I, Hanslik-Schnabel B, et al. Bone erosions and bone marrow edema as defined by magnetic resonance imaging reflect true bone marrow inflammation in rheumatoid arthritis. Arthritis Rheum. 2007; 56(4):1118-1124.
17. Kinnunen J, Bondestam S, Kivioja A, et al. Diagnostic performance of low field MRI in acute knee injuries. Magn Reson Imaging. 1994; 12(8):1155-1160.
18. Kladny B, Glückert K, Swoboda B, Beyer W, Weseloh G. Comparison of low-field (0.2 Tesla) and high-field (1.5 Tesla) magnetic resonance imaging of the knee joint. Arch Orthop Trauma Surg. 1995; 114(5):281-286.
19. Lassere M, McQueen F, Ostergaard M, et al. OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Studies. Exercise 3: An international multicenter reliability study using the RA-MRI Score. J Rheumatol. 2003; 30(6):1366-1375.
20. Lindegaard HM, Vallø J, Hørslev-Petersen K, et al. Low-cost, low-field dedicated extremity magnetic resonance imaging in early rheumatoid arthritis: a 1-year follow-up study. Ann Rheum Dis. 2006; 65(9):1208-1212.
21. Magee T, Shapiro M, Williams D. Comparison of high-field-strength versus low-field-strength MRI of the shoulder. AJR Am J Roentgenol. 2003; 181(5):1211-1215.
22. Maillefert JF, Dardel P, Cherasse A, et al. Magnetic resonance imaging in the assessment of synovial inflammation of the hindfoot in patients with rheumatoid arthritis and other polyarthritis. Eur J Radiol. 2003; 47(1):1-5.
23. McQueen FM, Benton N, Crabbe J, et al. What is the fate of erosions in early rheumatoid arthritis? Tracking individual lesions using x rays and magnetic resonance imaging over the first two years of disease. Ann Rheum Dis. 2001; 60(9):859-868.
24. Nikken JJ, Oei EH, Ginai AZ, et al. Acute peripheral joint injury: cost and effectiveness of low-field-strength MR imaging--results of randomized controlled trial. Radiology. 2005; 236(3):958-967.
25. Ostergaard M, Hansen M, Stoltenberg M, et al. Magnetic resonance imaging-determined synovial membrane volume as a market 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.
26. Rand T, Imhof H, Turetschek K, et al. Comparison of low field (0.2T) and high field (1.5T) MR imaging in the differentiation of torn from intact menisci. Eur J Radiol. 1999; 30(1):22-27.
27. Riel KA, Reinisch M, Kersting-Sommerhoff B, et al. 0.2-Tesla magnetic resonance imaging of internal lesions of the knee joint: a prospective arthroscopically controlled clinical study. Knee Surg Sports Traumatol Arthrosc. 1999; 7(1):37-41.
28. Shellock FG, Bert JM, Fritts HM, et al. Evaluation of the Rotator Cuff and Glenoid Labrum Using a 0.2-Tesla Extremity Magnetic Resonance (MR) System: MR Results Compared to Surgical Findings. J Magn Reson Imaging. 2001; 14:763-770
29. Tehranzadeh, J, Ashikyan O, Dascalos J. Advanced imaging of early rheumatoid arthritis. Radiol Clin North Am. 2004; 42(1):89-107. 
30. Tung GA, Entzian D, Green A, Brody JM. High-field and low-field MR imaging of superior glenoid labral tears and associated tendon injuries. AJR Am J Roentgenol. 2000; 174(4):1107-1114. 
31. Zlatkin MB, Hoffman C, Shellock FG. Assessment of the rotator cuff and glenoid labrum using an extremity MR system: MR results compared to surgical findings from a multi-center study. J Magn Reson Imaging. 2004; 19(5):623-631.

Government Agency, Medical Society, and Other Authoritative Publications:

1. American College of Rheumatology. Extremity Magnetic Resonance Imaging Task Force. Extremity magnetic resonance imaging in rheumatoid arthritis: report of the American College of Rheumatology Extremity Magnetic Resonance Imaging Task Force. Arthritis Rheum. 2006; 54(4):1034-1047.

Low Field MRI
Magnetic Resonance Imaging
Office MRI
Peripheral MRI