Table 1.

Characteristics of studies included in the present meta-analysis.

Reference	Yr	Country	Patients/controls	Method	TP	FP	FN	TN	Sensitivity (95% CI)	Specificity (95% CI)
Guohuai Zhang[11]	2019	China	47/1433	Color Doppler	47	1	2	1433	96 (86,100)	100 (100, 100)
Haijing Fan[12]	2020	China	20/234	Color Doppler	20	1	1	234	95 (76,100)	100 (98, 100)
Haohan Li[13]	2015	China	74/2926	Color Doppler	74	8	4	2926	95 (87, 99)	100 (99,100)
Jing Chen[14]	2020	China	10/190	Color Doppler	10	0	1	190	91 (59, 100)	100 (98, 100)

FN = false negative, FP = false positive, TN = true negative, TP = numbers of true positive.