Table. 2 The distribution of included quality according to QUADAS-2 tool
| Â | Afifi 2016 [9] | Du 2014 [10] | Ebraheem 2017 [11] | Goshima 2008 [12] | Hassan 2009 [13] | Kokabi 2015 [14] | Li 2016 [15] | Mannelli 2009 [16] | Wu 2017 [17] | Xiao 2008 [18] | Yousef 2017 [19] | Yuan 2014 [20] |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Ris of bias | U | U | U | L | U | U | U | L | U | L | U | L |
 Patient selection | L | L | L | L | L | L | L | L | L | L | L | L |
 Index Test | U | U | U | L | U | U | U | L | U | L | U | L |
 Reference standard | L | L | L | L | L | L | L | L | L | L | L | L |
 Flow and timing | L | L | L | L | L | L | L | L | L | L | L | L |
Applicability Concerns | L | L | L | L | L | L | L | L | L | L | L | L |
 Patient selection | L | L | L | L | L | L | L | L | L | L | L | L |
 Index Test | U | U | U | L | U | U | U | L | U | L | U | L |
 Reference standard | L | L | L | L | L | L | L | L | L | L | L | L |