Doppler US in rheumatic diseases with special emphasis on rheumatoid arthritis and spondyloarthritis

Abstract

Developments in digital ultrasonography (US) technology and the use of high-frequency broadband transducers have increased the quality of US imaging, particularly of superficial tissues. Thus, US, particularly color US or power Doppler US, in which high-resolution transducers are used, has become an important imaging modality in the assessment of rheumatic diseases. Furthermore, therapeutic interventions and biopsies can be performed under US guidance during the assessment of lesions. In this era of effective treatments, such as biologics, improvements in synovial inflammation in rheumatoid arthritis as well as changes in enthesitis in spondyloarthropathies, including ankylosing spondylitis and psoriatic arthritis, can be monitored effectively using gray-scale and/or power Doppler US. US is also a good imaging modality for crystal arthropathies, including gout and pseudogout, in which synovitis, erosions, tophi, and crystal deposition within or around the joint can be visualized readily. Vascular and tenosynovial structures, as well as the salivary glands, can be assessed with US in vasculitis and connective tissue disorders, including systemic lupus erythematosus and Sjögren's syndrome. Current research is focused on improving the sensitivity, specificity, validity, and reproducibility of US findings. In this review, we summarized the role of US, particularly power Doppler US, in rheumatic diseases and inflammation in superficial tissues.

Figures

Figure 1. a–c.

Change in the flow pattern of Doppler US with pressure. Right second metacarpophalangeal joint of a patient with rheumatoid arthritis shows flow signals within the joint (a). The flow signals reduce with mild pressure applied with the probe over the joint (b). The flow disappears with excessive pressure applied with the probe over the joint (c).

Figure 2. a–g.

The left hand of a 48-year-old female with rheumatoid arthritis. Photograph of the left hand (a) shows swelling in the wrist and second finger. Longitudinal power Doppler image (b) shows minimally increased vascularity in the left ulnocarpal joint. Longitudinal gray-scale US (c) shows cortical irregularity (arrows) in the second left metacarpophalangeal joint. Longitudinal power Doppler (d), transverse power Doppler (e), angled longitudinal power Doppler (f), volar aspect (g), and longitudinal power Doppler (f) images show severely increased vascularity with cortical penetration (f,arrows) in the second left metacarpophalangeal joint.

Figure 3. a, b.

Longitudinal US image (a) shows cortical irregularity at the Achilles tendon insertion, and transverse power Doppler image (b) shows grade 2 vascularization at the Achilles tendon insertion.

Figure 4. a–e.

A 23-year-old female with psoriatic arthritis. Photograph of the hands (a) shows psoriatic skin changes and swelling, especially in the right third distal interphalangeal joint and left fourth distal interphalangeal joint. Longitudinal (b) and transverse gray-scale (c) US show soft-tissue swelling and erosions (c,arrows) in the right third distal interphalangeal joint. Longitudinal power Doppler image (d) shows increased vascularity in the right third distal interphalangeal joint. Another longitudinal power Doppler image (e) shows increased vascularity in the right first distal interphalangeal joint.

Figure 5. a, b.

Gouty arthritis. The right hand second proximal interphalangeal (PIP) joint posteroanterior X-ray (a) and longitudinal B mode US (b) show erosion and tophi.

Figure 6. a, b.

Gouty arthritis. Longitudinal B-mode (a) and longitudinal power Doppler US (b) show tophi (a,arrow) and synovial vascularity and inflammation in the right third metatarsophalangeal joint.