Table 1.

Specification of machine used for hysterosalpingography in the study centers.

Machine Parameters	Names of diagnostic centers
	SW1	SW2	SW3	SW4
Name of Machine	Toshiba	GE	Allengers	GE
Type of Machine	Computed	Conventional	Computed	Conventional
Year of Manufacture	2011	2007	2014	2010
Filtration (mmAl)	0.90	1.60	0.90	0.83