The sacroiliac joints (SIJs) can be a source of posterior pelvic pain and guided injections can be useful for both diagnostic and therapeutic purposes. Fluoroscopy and CT can be both be used for SIJ guided injections. CT is preferred at many institutions, often due to the depth of the joint and variation in joint anatomy. 

Iodinated contrast, although not always used in CT-guided injections, can clearly demonstrate an intra-articular position. 

The volume of the SIJs are small, so the injectate volume should reflect this and is usually no more than 2 mL. The injectate mixture will consist of 1 mL of steroid and 0.5 mL-1 mL of local anesthetic. 

When selecting syringes, luer lock syringes are recommended to prevent syringe - needle detachment. Often the needle tip will be in the joint and no injectate can be administered. Fine needle repositing will be required whilst applying pressure to the syringe.