Background/Purpose:

MCP and PIP joints are frequently involved in rheumatoid arthritis. Complete ultrasound assessment of these joints requires the palmar and the dorsal approach for both the grey scale (GSUS) and the power Doppler (PDUS) modality. However, depending on the approach used, the frequency of findings consistent with synovitis seems to differ considerably. As ultrasound assessment increasingly influences our understanding of disease remission, this study was undertaken to investigate the role of palmar versus dorsal GSUS and PDUS in therapy-naive patients with rheumatoid arthritis.

Methods:

Patients with newly diagnosed and therapy-naive RA were included. Patients were assessed by clinical examination and ultrasound. Ultrasound was performed with grey scale (GSUS) and power Doppler (PDUS) of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints, using the dorsal and palmar approach. Synovitic findings in GSUS and PDUS were graded semiquantitatively from 0 to 3 as specified before. After the initial assessment, patients were treated with anti-rheumatic drugs according to national guidelines and were seen on a regular outpatient basis. Clinical and sonographic reevaluation together with assessment of EULAR responses was performed at month 6.  

Results:

Sofar, 40 patients with RA were included into this ongoing study. Palmar and dorsal GSUS identified 44.4% and 27.3% synovitic findings, respectively (p < 0.05). MCP joints with GSUS synovitis were tender and/or swollen in 53.4% and 62.6% in the palmar and volar approach, respectively (differences not significant). MCP joints with GSUS findings were PDUS positive in 17.8% using the volar approach compared to 71.7% using the dorsal approach (p < 0.001). Similar results were seen in the PIP joints with no significant differences concerning clinical concordance, while ultrasound concordance with PDUS was statistically significant between the palmar and dorsal approach.

Conclusion:

In therapy naïve RA patients, marked discrepancies between palmar and dorsal GSUS can be observed. While palmar GSUS detects significantly more synovitic findings than dorsal GSUS, both the clinical and PDUS concordances are low. The dorsal approach, on the other hand, shows significantly better concordance between GSUS and PDUS. The reasons are manifold  and include anatomical differences between the palmar and the dorsal aspect of the joints resulting in different sensitivities for GSUS and PDUS. In order to optimize ultrasonographic evaluation of small joints in RA, these findings require further clarification. Further analysis is underway to reassess GSUS and PDUS in these patients at month 6 of treatment.

---

« Back to 2012 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparing-palmar-and-dorsal-ultrasound-assessment-of-small-joint-synovitis-in-rheumatoid-arthritis-dorsal-greyscale-mode-yields-significantly-better-concordance-with-power-doppler/