Abstract

Nailfold capillaroscopy is used primarily to study microvascular structure, and in patients with Raynaud's phenomenon (RP) helps to differentiate between primary (idiopathic) RP and RP secondary to an underlying systemic sclerosis-spectrum disorder. In contrast, laser Doppler techniques measure microcirculatory blood flow, and therefore assess microvascular function. Capillaroscopy and laser Doppler are therefore complementary. There are different laser Doppler techniques: flowmetry (using a single probe), laser Doppler imaging (LDI), and laser speckle contrast imaging (LSCI). LDI and LCSI both measure blood flow over an area rather than at a single site. Laser Doppler techniques have been applied in research studies in patients with RP and systemic sclerosis, including as outcome measures in clinical trials: protocols often involve dynamic imaging, measuring blood flow response to (for example) a standard temperature stimulus.

This lecture will describe the main applications of capillaroscopy and laser Doppler techniques in clinical practice and research, relevant to the rheumatologist, and the rationale underpinning these.

Upon completion of the session, participants should be able to:

1. Discuss applications of capillaroscopy and different laser Doppler methods in patients with RP and systemic sclerosis

2. Discuss similarities and differences between the techniques.