Table 2.

Parameters for evaluating brown adipose tissue characteristics using near-infrared time-resolved spectroscopy (NIR_TRS) in the supraclavicular and control muscle regions.

					Correlation (r2)
					Supraclavicular region						Deltoid (forearm) region
Ref. no.	Instrument	n	Study design	Parameters	${\mu }_{\text{s}}^{\prime }$	Oxy-Hb	Deoxy-Hb	Total-Hb	StO2	AdjStO2	${\mu }_{\text{s}}^{\prime }$	Oxy-Hb	Deoxy-Hb	Total-Hb	StO2
Nirengi et al. (29)	NIRTRS	18	Cross-sectional	SUVmean	0.41*	0.52*	0.48*	0.53*	0.14*	0.07	0.08	0.25	0.21	0.20	0.08
				SUVmax	0.44*	0.52*	0.49*	0.53*	0.18*	0.08	0.04	0.27	0.23	0.12	0.05

The correlation coefficients of tissue-oxygenated hemoglobin (oxy-Hb), deoxygenated Hb (deoxy-Hb), total Hb (total-Hb), tissue Hb oxygen saturation (StO₂,), and optical scattering parameters as determined by NIR_TRS under thermoneutral conditions and the uptake of ¹⁸F-fluorodeoxy glucose (FDG) or cold-induced thermogenesis are presented.

${\mu }_{\text{s}}^{\prime }$, reduced scattering coefficient determined by NIR_TRS; adjusted StO₂ in the supraclavicular region relative to the deltoid muscle; SUV_mean, the mean standardized uptake value of the radioactivity (SUV) assessed by ¹⁸FDG–PET/CT; SUV_max, the maximal SUV assessed by ¹⁸FDG–PET/CT; BAT volume, evaluated by summating all voxel volume with SUV >2.0 assessed by ¹⁸FDG–PET/CT; Ref. no., reference number is obtained from the list of references in this paper.

^*P < 0.05.