What is the primary purpose of performing radionuclide cystography?

Radionuclide cystography is primarily performed to determine urinary reflux. This imaging technique uses a radiopharmaceutical that is administered into the bladder and allows healthcare professionals to visualize the bladder and the ureters during the process of voiding. One of the key indications for this procedure is to identify vesicoureteral reflux (VUR), a condition where urine flows backward from the bladder into the ureters and potentially the kidneys, which can lead to infections and other complications.

By monitoring the flow of the radioactive material during urination, clinicians can effectively see whether the urine is flowing in the correct direction and diagnose the presence of reflux. This assessment is vital, particularly in pediatric patients, as untreated VUR can cause renal damage over time.

Evaluating bladder capacity and assessing renal function are important aspects of urological health but are not the primary focus of radionuclide cystography. Similarly, while diagnosing kidney stones is a relevant concern in urology, it is typically addressed through different imaging modalities, such as ultrasound or CT scans. Thus, the correct answer, identifying the primary purpose as determining urinary reflux, highlights the specific application of radionuclide cystography in clinical practice.