Table 3.

Performance of U-Net Models for Segmentation of Lung and Lesions

Lung Segmentation	DSC	Jaccard	RVD
Overall	0.981	0.965	−0.46%
Moderate	0.990	0.980	0.63%
Severe	0.987	0.975	0.16%
Critical	0.961	0.935	−2.56%
(Lesion Segmentation, DSC, Jaccard, RVD)
Overall	0.778	0.663	2.1%
Moderate	0.746	0.619	3.1%
Severe	0.790	0.671	2.6%
Critical	0.826	0.723	−3.3%

Note:

• Dice similarity coefficient (DSC): 2*TP / ( 2*TP + FP + FN ).

• Jaccard index: TP / ( TP + FP + FN ).

• Relative volume difference (RVD): (Vol(res) / Vol(ref) -1) *100%.

res: automated segmentation results exported by U-Net.

ref: reference segmentation results contoured by radiologists.