Table 5.

Methodological scoring system (points) for included articles (total scoring; maximum = 24 points)

	Ono et al. [31]	Pirilä-Parkkinen et al. [32]	Zhang et al. [38]	Glupker et al. [39]
I. Study design (maximum score = 11 points)
A. Time	2	2	2	1
B. Randomized sample	0	0	0	0
C. Control group	0	1	0	0
D. Sample size	0	2	0	1
E. Sample gender	1	0	0	1
F. Objective	1	1	1	0
G. Selection criteria	1	1	1	1
H. Baseline characteristics	0	1	0	0
Score	5	8	4	4
II. Study measurements (maximum score = 9 points)
A. Segmentation method (manually or automated)	0	0	0	0
B. Part of airway	1	1	1	0
C. Type of airway measurements	3	2	3	2
D. Airway measurements adjusted	0	0	0	0
E. Method of acquisition	1	1	1	0
F. Blinding measurements method	0	0	0	1
Score	5	4	5	3
III. Data analysis (maximum score = 4 points)
A. Statistical analysis	1	1	1	1
B. Validation of measurements (error of the method)	0	1	0	1
C. Data presentation	2	2	2	2
Score	3	4	3	4
Total score	13	16	12	11
Total score %	13/24 x 100 ≈ 54	16/24 x 100 ≈ 67	12/24 x 100 ≈ 50	11/24 x 100 ≈ 46
Mean quality % of the studies	(54 + 67 + 50 + 46)/4 = 54