Prognostic Values of the Gray-to-White Matter Ratio on Brain Computed Tomography Images for Neurological Outcomes after Cardiac Arrest: A Meta-Analysis

Table 1

Study characteristics of included studies.

First author	Publication year	Country	Time of CT measurement	Study design	Cardiac etiology (%)	Method of GWR measurement	Sample size	CT scanner (manufacturers/row/slice thickness)	GWR calculation	TTM (%)	AUC	Cutoff	GWR value
													Good outcome	Poor outcome
Chae et al. [4]	2016	Korea	Within 6 h after ROSC	R	56%	GWR-AV	119	GE/NA/5 mm	Manual	100%	0.65	1.24	1.23 (0.05)	1.19 (0.08)
Choi et al. [5]	2008	Korea	Within 24 h after resuscitation	R	46%	GWR-BG	28	GE/NA/5 mm	Manual	NA	0.947	1.22	1.28 (0.01)	1.19 (0.01)
Cristia et al. [6]	2014	USA	Within 24 h after ROSC	R	NA	GWR-AV	77	GE/16 or 64 rows/5 mm	Manual	70%	0.64	1.20	NA	NA
Gentsch et al. [7]	2015	Germany	Within 7 days after arrest	R	53%	GWR-SI	98	GE/16 rows/5 mm	Manual	100%	0.810	1.11	NA	NA
Hanning et al. [8]	2016	Germany	Within 24 h after arrest	R	39%	GWR-SI	84	NA	Automated	NA	0.860	1.084	1.10 (1.08-1.12)	1.06 (1.05-1.08)
Inamasu et al. [9]	2011	Japan	Within 2 h of arrival	R	0%	GWR-SI	39	GE/16 rows/5 mm	Manual	NA	NA	NA	NA	NA
Jeon et al. [10]	2017	Korea	Within 6 h after arrest	R	49%	GWR-AV	39	Philips/64 rows/NA	Manual	0%	0.891	1.21	1.27 (1.24-1.31)	1.17 (1.14-1.21)
Kim et al. [11]	2013	Korea	Within 1 h after resuscitation	R	69%	GWR-AV	51	GE/64 rows/5 mm	Manual	100%	0.747	1.24
Kim et al. [12]	2014	Korea	Within 24 h after ROSC	R	38%	GWR-AV	91	NA	Manual	44%	0.922	1.23
Lee et al. [13]	2013	Korea	Within 3.5 h after ROSC	R	76%	GWR-SI	224	NA	Manual	100%	0.864	1.17	1.25 (1.21-1.32)	1.17 (1.13-1.21)
Lee et al. [14]	2015	Korea	Within 24 h after ROSC	R	100%	GWR-AV	283	NA	Manual	100%	0.591	1.26	1.318 (1.285-1.368)	1.302 (1.257-1.350)
Lee et al. [15]	2016	Korea	Within 24 h after ROSC	R	0%	GWR-AV	164	NA	Manual	100%	0.638	1.22	NA	NA
Lee et al. [16]	2018	Korea	Within 24 h after resuscitation	R	52%	GWR-SI	258	NA	Manual	100%	0.60	1.14	1.15 (1.11-1.22)	1.13 (1.07-1.19)
Lee et al. [17]	2017	Korea	Within 6 h after arrest	R	55%	GWR-AV	67	Siemens/16 rows/5 mm	Manual	100%	NA	1.13
Lee et al. [18]	2016	Korea	Within 1 h after ECMO pump	R	NA	GWR-BG	30	Siemens/64 rows/5 mm	Manual	100%	0.872	1.24	1.28 (1.24-1.40)	1.17 (1.12-1.24)
Liu et al. [19]	2017	China	Within 5 days after ROSC	R	60%	GWR-BG	43	NA	Manual	100%	0.756	1.13
Metter et al. [20]	2011	USA	Within 24 h after arrest	P	NA	GWR-AV	240	GE/NA/5 mm	Manual	70%	0.72	1.20	1.26 (1.24-1.30)	1.22 (1.16-1.27)
Ryu et al. [21]	2017	Korea	Within 48 h after ECPR	R	83%	GWR-BG	42	GE/64 rows/5 mm	Manual	38%	0.792	1.23	1.31 (1.25-1.37)	1.21 (1.11-1.28)
Scarpino et al. [22]	2019	Italy	Within 24 h after arrest	P	NA	GWR-BG	346	NA	Manual	40%	0.87	1.21	NA	NA
Son et al. [23]	2020	Korea	Within 6 h after ROSC	R	30%	GWR-AV	58	Siemens/64 rows/5 mm	Manual	0%	0.719	1.07	1.24 (1.19-1.29)	1.16 (1.11-1.24)
Streitberger et al. [24]	2019	Germany	24 h-10 days after arrest	R	46%	GWR-AV	108	GE/NA/5 mm	Manual	100%	0.80	1.13	NA	NA
Torbey et al. [25]	2000	USA	Within 24 h after arrest	R	NA	GWR-AV	25	GE/NA/5 mm	Manual	NA	NA	1.18	NA	NA
Wang et al. [26]	2018	China	Within 72 h after resuscitation	R	22%	GWR-BG	58	GE/16 rows/5 mm	Manual	100%	0.698	1.18	1.24 (1.20-1.32)	1.19 (1.11-1.25)
Youn et al. [27]	2017	USA	Within 24 h after arrest	R	NA	GWR-AV	240	GE/NA/5 mm	Manual	91%	0.726	1.10

AUC: area under the curve; AV: average; BG: basal ganglia; ECMO: extracorporeal membrane oxygenation; ECPR: extracorporeal cardiopulmonary resuscitation; GWR: gray-to-white ratio; P: prospective; R: retrospective; SI: simplified estimation method; TTM: targeted temperature management.