Comparison of laser speckle contrast imaging with laser Doppler for assessing microvascular function

Tew, Garry, Klonizakis, Markos, Crank, Helen, Briers, David and Hodges, Gary (2011) Comparison of laser speckle contrast imaging with laser Doppler for assessing microvascular function. Microvascular Research, 82 (3). pp. 326-332. ISSN 0026-2862

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Abstract

Objective
To compare the inter-day reproducibility of post-occlusive reactive hyperaemia (PORH) and sympathetic vasomotor reflexes assessed by single-point laser Doppler flowmetry (SP-LDF), integrating-probe LDF (IP-LDF) and laser speckle contrast imaging (LSCI), and the spatial variability of PORH assessed by IP-LDF and LSCI. We also evaluated the relationship between IP-LDF and LSCI perfusion values across a broad range of skin blood flows.

Methods
Eighteen healthy adults (50% male, age 27 ± 4 years) participated in this study. Using SP-LDF, IP-LDF and LSCI, indices of skin blood flow were measured on the forearm during PORH (1-, 5- and 10-min occlusions) and on the finger pad during inspiratory gasp and cold pressor tests. These tests were repeated 3–7 days later. Data were converted to cutaneous vascular conductance (CVC; laser Doppler flow/mean arterial pressure) and expressed as absolute and relative changes from pre-stimulus CVC (ΔCVCABS and ΔCVCREL, respectively), as well as normalised to peak CVC for the PORH tests. Reproducibility was expressed as within-subjects coefficients of variation (CV, in %) and intraclass correlation coefficients.

Results
The reproducibility of PORH on the forearm was poorer when assessed with SP-LDF and IP-LDF compared to LSCI (e.g., CV for 5-min PORH ΔCVCABS = 35%, 27% and 19%, respectively), with no superior method of data expression. In contrast, the reproducibility of the inspiratory gasp and cold pressor test responses on the finger pad were better with SP-LDF and IP-LDF compared to LSCI (e.g., CV for inspiratory gasp ΔCVCREL = 13%, 7% and 19%, respectively). The spatial variability of PORH responses was poorer with IP-LDF compared to LSCI (e.g., CV ranging 11–35% versus 3–16%, respectively). The association between simultaneous LSCI and IP-LDF perfusion values was non-linear.

Conclusion
The reproducibility of cutaneous PORH was better when assessed with LSCI compared to SP-LDF and IP-LDF; probably due to measuring larger skin areas (lower inter-site variability). However, when measuring sympathetic vasomotor reflexes on the finger pad, reproducibility was better with SP-LDF and IP-LDF, perhaps due to the high sensitivity of LSCI to changes in skin blood flow at low levels.

Item Type:	Article
Subjects:	A300 Clinical Medicine B100 Anatomy, Physiology and Pathology
Department:	Faculties > Health and Life Sciences > Sport, Exercise and Rehabilitation
Depositing User:	Prof Garry Tew
Date Deposited:	04 Aug 2015 15:29
Last Modified:	12 Oct 2019 15:29
URI:	http://nrl.northumbria.ac.uk/id/eprint/23502

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