Table 1.

Classical approaches for COVID-19 using CT-scan

Authors	Database (CT Images)	Segmentation	No. of patient	Accuracy (%)
Jun Chen et al. [17]	46,096	UNet++	106 with 51 + ve	95.24%
Shuai Wang et al. [104]	453	–	99	82.90%
Xiaowei Xu et al. [115]	618	VNet	219 with 110 + ve	86.70%
Ying Song et al. [93]	777		88	86.00%
Opir Gozes et al. [34]		U-Net	56	99.60%
Fei Shan [85]	249	VB-Net	249	91.60%
Cheng Jin et al. [43]	970	2D CNN	496	94.98%
Mucahid Barstuga et al. [9]	150	–	–	99.68%
Lin Li [62]	4356	U-Net	3322	–
Chuansh Zheng [90]	–	U-Net	540	95.90%
Shua Jin [44]	–	UNet++	1136 with 723 + ve	–