Table 2.

Quantitative values from 3D iodine density histogram and ECV and cutoff value of the 8 parameters.

Parameters	Mean ± SD	Cutoff value
Max (100ug/cc)	72.9 ± 33.7	≤ 71
Score = 0 (n = 18)	90.9 ± 39.9
Score = 1 (n = 19)	55.8 ± 11.8
Min (100ug/cc)	− 114.3 ± 18.7	≤ − 104
Score = 0 (n = 9)	− 91.9 ± 11.8
Score = 1 (n = 28)	− 121.5 ± 14.2
Median (100ug/cc)	26.3 ± 4.7	> 28
Score = 0 (n = 27)	24.0 ± 3.1
Score = 1 (n = 10)	32.5 ± 2.1
Mean (100ug/cc)	12.3 ± 5.3	> 13.9
Score = 0 (n = 23)	9.2 ± 3.9
Score = 1 (n = 14)	17.5 ± 2.5
SD (100ug/cc)	37.5 ± 9.3	≤ 36
Score = 0 (n = 22)	43.5 ± 6.5
Score = 1 (n = 15)	28.6 ± 4.4
Skewness	− 2.2 ± 0.8	≤ − 2.3
Score = 0 (n = 20)	− 1.6 ± 0.4
Score = 1 (n = 17)	− 2.9 ± 0.5
Kurtosis	7.5 ± 4.3	> 6.2
Score = 0 (n = 19)	4.2 ± 1.2
Score = 1 (n = 18)	10.8 ± 3.6
ECV (%)	17.5 ± 7.2	> 21.2
Score = 0 (n = 26)	14.2 ± 5.8
Score = 1 (n = 11)	25.2 ± 3.1

Optimal thresholds were determined for each variable separately using the Youden index to predict the high PD-L1 expression (TPS ≥ 50%).

The group that met the cutoff value condition was graded as score = 1 and the other group was graded as score = 0.

ECV extracellular volume, TPS tumor proportion score.