[1] The technique consists of catheterizing the person in order to fill the bladder with a radiocontrast agent, typically diatrizoic acid.
Under fluoroscopy (real time x-rays) the radiologist watches the contrast enter the bladder and looks at the anatomy of the patient.
If the contrast moves into the ureters and back into the kidneys, the radiologist makes the diagnosis of vesicoureteral reflux, and gives the degree of severity a score.
[2] Indications for performing VCUG: Contraindications for voiding cystourethrogram is when the subject is having: A high osmolar contrast agent such as diatrizoate or a low osmolar contrast agent such as Iotalamic acid with a concentration of 150 mg per ml is used for the procedure.
[2] With respect to post-procedural urinary tract infection, the risk has been found to be sufficiently low, except in patients with a pre-existing urologic diagnosis, that pre-operative antibiotic use is not considered a necessary adjunct.
[5] The procedure is invasive and uncomfortable, and it carries a high potential for psychological trauma for both children and parents.
[1][6] The long-term psychological effects of VCUGs on children have been compared to that of childhood sexual abuse.
Accidental catherisation of vagina or unusual urethral opening and retention of urinary catheter are also possible.