Imaging Technology Only as Good as Man and Machine

Imaging in rheumatology has come a long way in the past two decades. From diagnosis to assessment and monitoring, today imaging technology - such as high-resolution grey-scale ultrasound and highly sensitive Doppler mode - can steer a new course for patients with rheumatic and musculoskeletal diseases.

But how well the technology works depends on the skill of the technician and the quality of the machine, write the authors of a review published in the January-February issue of Clinical and Experimental Rheumatology.  They cite a study in which the concordance between ultrasonographers with high experience in ultrasound who used good quality machines was significant (median kappa 0.64 for grey-scale ultrasound and Doppler synovitis and 0.41 for erosions), as was the correlation between less experienced technicians and low quality machines.

In this review, Esperanza Naredo of the Hospital General Universitario in Spain, provides an evidence-based update on the role of ultrasound in rheumatoid arthritis, spondyloarthitis, osteoarthritis and juvenile idiopathic arthritis. The review is based on a literature search of PubMed and Embase published in 2015.

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Doppler mode, either color Doppler (CD) or power Doppler (PD), can detect pathological synovial and tenosynovial flow, which is a marker of synovial inflammatory activity. Naredo cited one study in which both grey-scale ultrasound and power Doppler synovitis reflected synovial inflammation in early rheumatoid arthritis.

In terms of its ability to diagnose disease, positive power Doppler synovial signals were a predictor of high risk progression to established arthritis, according to a study of 100 patients with non-specific musculoskeletal disease symptoms and positive anticyclic citrullinated peptide (anti-CCP) antibodies. Half of the patients in the study developed inflammatory arthritis after a median 7.9 months (0.1–52.4), the majority (86%) fulfilling the 2010 American College of Rheumatology/European League Against Rheumatism (EULAR) criteria for rheumatoid arthritis.

Assessment of structural damage in rheumatoid arthritis

Naredo and colleagues cite a study in which Peluso et al. investigated the performance of 3D ultrasound to detect bone erosions in hand and wrist joints of 20 early rheumatoid arthritis patients without erosions on radiography (using computed tomography (CT) as the reference method). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 3D ultrasound as compared with computed tomography was 0.9, 0.55, 0.71 and 0.83, respectively.

D’Agostino et al. undertook an international, multicenter, open-label, single-arm clinical trial to assess the responsiveness of a combined power Doppler and grey-scale ultrasound synovitis score (Global OMERACTEULAR Synovitis Score (GLOESS)) in patients with rheumatoid arthritis starting abatacept. DAS28 significantly decreased from weeks 1 to 24, reaching clinical meaningful improvement at week 8.

Prognostication of outcomes

A study by Sreerangaiah et al. confirmed that Doppler-detected synovial vascularity  (either with 2D or 3D ultrasound) in wrist and MCP joints was highly associated with structural damage progression at 12 months in 85 RA patients with seropositive early rheumatoid arthritis.  A study by Naredo and colleagues investigated the predictive value of ultrasound-detected synovitis in relation to failed tapering of biologic therapy in 77 rheumatoid arthritis patients in sustained clinical remission. At 12 months, 45.5% of patients presented BT tapering failure, 29.9% in the first 6 months.

Diagnostic performance in psoriatic arthritis

Ultrasound has been used to detect a variety of inflammatory findings in early psoriatic arthritis (PsA) as shown in a study by Bandinelli et al. who described wrist and hand US abnormalities in 112 cases. Grey-scale ultrasound and power Doppler synovitis, tenosynovitis, peritendinitis and erosions were found independently of the clinical findings.

Osteoarthritis

The role that inflammation plays in the pathogenesis of osteoarthritis is under investigation. Naredo wrote that there is little information on the responsiveness of musculoskeletal ultrasound (MSUS) findings in osteoarthritis. Four studies have looked into this issue over the last four years (two on hand OA and two studies on knee OA). Power Doppler synovitis was associated with radiographic worsening, particularly with bone erosion development or progression. However, in the study by Kortekaas et al. grey-scale GS synovial thickening was also associated with erosive deterioration.

Juvenile idiopathic arithitis

Over the past years, musculoskeletal ultrasound (MSUS) has been increasingly implemented in paediatric rheumatology. Naredo recommends the use MSUS to diagnose JIA. She cited one study (Nieto et al) in which the researcher evaluated the extent to which musculoskeletal ultrasound influenced the diagnosis and management decisions in daily clinical practice. Nieto found that in 65 of 111 patients who had a musculoskeletal ultrasound, the initial diagnosis was changed for 38 patients. 

Naredo concludes by recommending that MSUS be used to detect early joint damage and monitor disease activity as well as using ultrasound as a tool to assess prognosis and the “the accurate placement of intra-articular injections.”

References:

E. Naredo and A. Iagnocco. "Review:  One year in review: ultrasound in arthritis," Clinical and Experimental Rheumatology. January February 2016. Clin Exp Rheumatol 2016; 34: 1-10.