Background Even though Doppler ultrasound (US) is used for diagnosing inflammatory changes it is well-known that Doppler signals are seen in healthy wrist and finger joints (1). Tenosynovitis has been shown to be frequent in rheumatoid arthritis and to predict erosive disease (2). Detailed knowledge of the distribution of feeding vessels in fingers is important to distinguish normal from pathological findings. However, there is no knowledge about Doppler signals in relation to healthy tendon sheaths and the possible pitfalls this may generate.

Objectives To investigate presence of feeding vessels in relation to the healthy flexor tendon sheaths of the fingers by use of 3D Doppler US.

Methods Twenty healthy participants were recruited, 10 women in the age 23-67 years and 10 men in the age 26-54 years. None of the participants had finger pain, history of arthritis or any known finger tendon disease. One participant was a smoker.

The participants had US of the right second and third flexor tendon of the finger (10 men, 10 women). US was carried out using a General Electric Logiq E9 with a 3D ultrasound probe. The Doppler settings were adjusted according to published recommendations (3) with a Doppler frequency of 8.3 MHz and pulse repetition frequency of 0.4. The same Doppler settings were used for all examinations. Specific probe positions on the fingers were selected before study initiation. Two scans were made at each position to minimise the risk of missing Doppler findings, due to different parts of the cardiac cycle being sampled as the sweep was made. Each tendon sheath was divided into specific areas and the visualized 3D Doppler findings in relation to the tendon sheath were plotted on a schematic drawing (Figure 1A).

Results Nutrition vessels in relation to flexor tendons were seen in all 20 healthy controls distal part of

The overall distribution of feeding vessels between the 2nd and 3rd flexor tendon were comparable and is shown in Figure 1A.

The feeding vessels were predominantly seen at ulnar and radial locations, except in the distal part of the metacarpal bones, where the palmar location was common (Figure 1B+C). Palmar vessels were more frequent distally than proximally in the fingers and the dorsal vessels were extremely rare.

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Conclusions Doppler findings in close relation to the tendon sheaths, due to feeding vessels, were common in flexor tendons of the fingers in healthy participants and may be a cause of misinterpretation due to artefacts. These vessels should be taken into consideration when diagnosing tenosynovitis.

References

1. Terslev L, Torp-Pedersen S, Qvistgaard E, von der Recke P, Bliddal H. Doppler ultrasound findings in healthy wrists and finger joints. Annals of the rheumatic diseases. 2004;63(6):644-8.

2. Lillegraven S, Boyesen P, Hammer HB, Ostergaard M, Uhlig T, Sesseng S, et al. Tenosynovitis of the extensor carpi ulnaris tendon predicts erosive progression in early rheumatoid arthritis. Annals of the rheumatic diseases. 2011;70(11):2049-50.

3. Torp-Pedersen ST, Terslev L. Settings and artefacts relevant in colour/power Doppler ultrasound in rheumatology. Annals of the rheumatic diseases. 2008;67(2):143-9.

Disclosure of Interest None declared