Assessing Synovitis and Bone Erosion With Apparent Diffusion Coefficient in Early Stage of Rheumatoid Arthritis:

Evaluation of Synovitis of Hand in Patients With Rheumatoid Arthritis Using Diffusion Kurtosis Magnetic Resonance Imaging: Initial Findings

OBJECTIVE

To explore the role of diffusion kurtosis magnetic resonance (MR) imaging in the noninvasive identification of synovitis in hand arthritis.

METHODS

A total of 30 patients with rheumatoid arthritis (RA) and 10 patients suspected of RA were enrolled in the prospective study. A 3.0-T MR imaging including the diffusion kurtosis MR imaging sequence (b = 0, 500, 1000, 1500, 2000 s·mm2) was performed. A total of 210 regions of interest were confirmed and diffusion kurtosis MR imaging parameters were generated. The suspected synovitis or effusion was scored on a scale of 0 (effusion) to 3 (mild, moderate, severe synovitis), according to RA-MR imaging scoring system. The performance of diffusion kurtosis MR imaging parameters (the apparent diffusion coefficient [ADC], diffusion coefficient [D], and kurtosis [K]) in distinguishing different synovitis scores was evaluated.

RESULTS

There were significant differences in ADC, D, and K values among different synovitis scores (all P < 0.001). Synovitis scores were negatively correlated with the ADC and D values significantly (r = -0.725, -0.757, respectively, all P < 0.001), but positively correlated with the K values significantly (r = 0.429, P < 0.001). The area under the curve values of D, ADC, and K values were 0.884, 0.874, and 0.728 for differentiating score 1-3 from score 0, respectively. Diffusion coefficient and ADC had similar diagnostic performance, and both were higher than K in detecting synovitis. No significant difference was found between the ADC and D values in detecting synovitis.

CONCLUSIONS

The diffusion kurtosis MR imaging may be feasible as a noninvasive method for the diagnosis and grading of synovitis in the hands of RA patients, and the D and ADC values showed similar diagnostic performance, both of which were higher than K values.

Emerging quantitative MR imaging biomarkers in inflammatory arthritides

PURPOSE

To review quantitative magnetic resonance imaging (qMRI) methods for imaging inflammation in connective tissues and the skeleton in inflammatory arthritis. This review is designed for a broad audience including radiologists, imaging technologists, rheumatologists and other healthcare professionals.

METHODS

We discuss the use of qMRI for imaging skeletal inflammation from both technical and clinical perspectives. We consider how qMRI can be targeted to specific aspects of the pathological process in synovium, cartilage, bone, tendons and entheses. Evidence for the various techniques from studies of both adults and children with inflammatory arthritis is reviewed and critically appraised.

RESULTS

qMRI has the potential to objectively identify, characterize and quantify inflammation of the connective tissues and skeleton in both adult and pediatric patients. Measurements of tissue properties derived using qMRI methods can serve as imaging biomarkers, which are potentially more reproducible and informative than conventional MRI methods. Several qMRI methods are nearing transition into clinical practice and may inform diagnosis and treatment decisions, with the potential to improve patient outcomes.

CONCLUSIONS

qMRI enables specific assessment of inflammation in synovium, cartilage, bone, tendons and entheses, and can facilitate a more consistent, personalized approach to diagnosis, characterisation and monitoring of disease.

MRI and ultrasound of the hands and wrists in rheumatoid arthritis. I. Imaging findings

The management of patients with rheumatoid arthritis (RA) has rapidly evolved with the development of newer disease-modifying drugs and the recognition that long-term damage can be mitigated by an earlier and more-informed use of these medications. Historically, radiographs were the mainstay of imaging in RA patients, but radiographic joint narrowing and erosions are late and insensitive findings in the disease. MRI (with intravenous contrast agent) and ultrasound (with power Doppler interrogation) of the hands and wrists are able to demonstrate erosions earlier and with greater sensitivity than radiographs. More importantly, these imaging studies also depict synovitis and active soft-tissue inflammation, which represents a precursor to structural damage. Additionally, MRI can show inflammation within the bones (osteitis), which is proving to be the most important prognosticator of an aggressive disease course. Part I of this review discusses the imaging techniques, pitfalls, definitions, and comparative studies of MRI and ultrasound for identifying and quantifying erosions, synovitis, and osteitis. Part II will demonstrate how these imaging findings influence the clinical management of RA patients throughout their disease course, from presentation through clinical remission.