Table 1.

Study characteristics

Reference	Year	Country	Study design	Modality	Reference standard	Definition target condition
Borushok et al.24	1990	USA	R	US	S+PA	Perforated
Choi et al.25	1998	USA	U	CT	S+PA	Necrotizing and perforated appendicitis
Foley et al.26	2005	USA	R	CT	S+PA	Perforated
Miki et al.27	2005	Japan	R	CT	S+PA	Gangreneous and perforated appendicitis
Tsuboi et al.28	2008	Japan	R	CT	S+PA	Perforated
Seo et al.29	2009	South Korea	R	CT H/L	S+PA	Perforated
Suthikeeree et al.30	2010	Thailand	R	CT	S+PA	Perforated
Kim et al.31	2011	South Korea	R	CT H/L	S+PA	Perforated
Suh et al.32	2011	South Korea	R	CT	S+PA	Perforated
Kim et al.33	2012	South Korea	P	CT H/L	S+PA	Perforated
Leeuwenburgh et al.34	2014	Netherlands	P	US, US+CT, MRI	S+PA	Perforated appendicitis or pus in abdomen
Liu et al.35	2015	China	R	CT	S+PA	Perforated
Ali et al.23	2018	Pakistan	U	CT	PA	Perforated

R, retrospective; US, ultrasonography; S, surgery; PA, histopathology; U, uncertain; H/L, high and low radiation dose; P, prospective.