Table 3.

RQS rating of included studies

16 Items according to 6 key domains	Range	Median (range)	Percentage of ideal score, n (%)	Adherence rate, n (%)
Total 16 items	− 8 to 36	11 (− 2 to 16)	9.3 (26)	65/144 (45)
Domain 1: protocol quality and stability in image and segmentation	0 to 5	2 (1 to 2)	1.9 (38)	17/36 (47)
Protocol quality	0 to 2	1 (1 to 1)	1.0 (50)	9/9 (100)
Multiple segmentations	0 to 1	1 (0 to 1)	0.9 (89)	8/9 (89)
Test–retest	0 to 1	0 (0 to 0)	0.0 (0)	0/9 (9)
Phantom study	0 to 1	0 (0 to 0)	0.0 (0)	0/9 (0)
Domain 2: feature selection and validation	− 8 to 8	5 (− 8 to 6)	1.3 (17)	13/18 (72)
Feature reduction or adjustment of multiple testing	− 3 to 3	3 (− 3 to 3)	2.3 (78)	8/9 (89)
Validation	− 5 to 5	2 (− 5 to 3)	− 1.0 (0)	5/9 (56)
Domain 3: biologic/clinical validation and utility	0 to 6	3 (2 to 6)	3.6 (59)	21/36 (58)
Non-radiomics features	0 to 1	1 (0 to 1)	0.6 (56)	5/9 (56)
Biologic correlations	0 to 1	1 (0 to 1)	0.6 (56)	5/9 (56)
Comparison to “gold standard”	0 to 2	0 (0 to 2)	0.4 (22)	2/9 (22)
Potential clinical utility	0 to 2	2 (2 to 2)	2.0 (100)	9/9 (100)
Domain 4: model performance index	0 to 5	2 (1 to 4)	2.3 (47)	12/27 (44)
Cut-off analysis	0 to 1	0 (0 to 0)	0.0 (0)	0/9 (0)
Discrimination statistics	0 to 2	2 (1 to 2)	1.7 (83)	9/9 (100)
Calibration statistics	0 to 2	0 (0 to 2)	0.7 (33)	3/9 (33)
Domain 5: high level of evidence	0 to 8	0 (0 to 0)	0.0 (0)	0/18 (0)
Prospective study	0 to 7	0 (0 to 0)	0.0 (0)	0/9 (0)
Cost-effectiveness analysis	0 to 1	0 (0 to 0)	0.0 (0)	0/9 (0)
Domain 6: open science and data	0 to 4	0 (0 to 1)	0.2 (6)	2/9 (22)

The ideal score was described as score and percentage of score to ideal score for each item. In the cases where a score of one point per item was obtained, the study was considered to have basic adherence to each item. The adherence rate was calculated as proportion of the number of articles with basic adherence to number of total articles. The bolded numbers indicated the sum of domains or RQS

RQS radiomics quality score