(Ultrasound Review) Power Doppler sonography may be a valuable tool for differentiating inflammatory and non-inflammatory pannus in the knee of patients with rheumatoid arthritis, according to the results of a prospective study conducted at University Ancona in Jesi, Italy. This recent research was published in Annals of Rheumatologic Disease.
The authors reported that "proliferation of the synovial tissue resulting in the formation of synovial pannus is an early event in the course of the disease and can be seen before destruction of cartilage and bone."
By using power Doppler to assess the vascularity of the pannus an estimation of disease activity can be made. The objective of the study was to determine the usefulness of ultrasound by comparing ultrasound results with the clinical findings and laboratory measures of disease activity.
MRI has been shown to accurately demonstrate the rate of progression of joint destruction. Compared with MRI, ultrasound is a noninvasive, reproducible and relatively inexpensive diagnostic tool, they said.
An ultrasound contrast agent (Levovist) was used to enhance Doppler signals and improve the detection of low flow around the joint. Synovial membrane blood flow was quantified using time-intensity curves and calculation of the area under the curve. A 10-13MHz linear array transducer was used on an Esaote AU3 harmonic system with software that enabled analysis of Doppler signal intensity before and after contrast injection.
Results demonstrated a significant correlation between the area under the curve and the degree of knee inflammation. Also, there was a stronger correlation with the disease activity score and the chronic arthritis systemic index, which were used to clinically evaluate disease activity. The authors concluded "the transit of microbubbles of ultrasound contrast across a tissue can be used to estimate haemodynamic alterations and may have a role in assessing synovial activity and the therapeutic response to treatment of synovitis of the knee."
Power Doppler sonography in the assessment of synovial tissue of the knee joint in rheumatoid arthritis: a preliminary experienceCarotti M et al
Dept of rheumatology, University of Ancona, Jesi, Italy
Ann Rheum Dis 2002 September; 61:877-882
By Ultrasound Review
November 12, 2002
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