Table 1.

Reliability and validity of LSCI and thermography (standard and mobile phone–based) in patients with systemic sclerosis–related Raynaud's phenomenon^a

Summary measure	Test–retest reliability			Difference in reliability,	Validity
	LSCI (n = 159)	Standard thermography (n = 159)	Mobile phone thermography (n = 141)b	LSCI versus standard thermography	LCSI and standard thermography	Standard and mobile phone thermography
Distal dorsal difference	0.67 (0.56, 0.77)	0.58 (0.43, 0.71)	0.61 (0.51, 0.73)	0.08 (−0.05, 0.25)	0.65 (0.50, 0.79)	0.90 (0.79, 0.97)
Reperfusion/rewarming AUClog	0.67 (0.54, 0.76)	0.68 (0.58, 0.80)	0.61 (0.51, 0.72)c	−0.01 (−0.17, 0.11)	0.94 (0.87, 1.00)	0.98 (0.94, 1.00)
MAXlog	0.64 (0.52, 0.75)	0.72 (0.64, 0.81)	NA	−0.09 (−0.21, 0.03)	0.87 (0.77, 0.95)	NA
Gradient over first 2 minutes	0.46 (0.40, 0.69)	0.56 (0.40, 0.74)	NA	−0.09 (−0.24, 0.18)	0.52 (0.33, 0.70)	NA

^aData for the summary measures of distal dorsal difference, reperfusion/rewarming area under the curve (AUC_log), maximum blood flow rate/skin temperature after rewarming (MAX_log), and gradient of reperfusion/rewarming over the first 2 minutes have been averaged over 8 digits. Values are the intraclass correlation coefficients (ICCs) (with 95% confidence intervals [95% CIs]) for the test–retest reliability of laser speckle contrast imaging (LSCI), standard thermography, and mobile phone–based thermography, the difference (with 95% CIs) in ICC point estimates between LSCI and standard thermography, and the estimated validity, expressed as latent correlation coefficients (with 95% CIs), between LSCI and standard thermography and between standard and mobile phone thermography. NA = not applicable.

^bFor mobile phone thermography, 141 data sets were available (n = 18 missing due to technical fault at 2 of the centers).

^cThe AUC_log for mobile phone thermography was approximated from the mean values of 2 frames, post–cold challenge of the hand.