Ureteral Stones Diagnosis and Tests

While CT is the gold standard, other imaging modalities play specific roles. Ultrasound is the primary diagnostic tool for pregnant women and children to avoid radiation exposure. It relies on sound waves to visualize the kidney and bladder. While excellent at detecting hydronephrosis (the swelling caused by the blockage), ultrasound is notoriously poor at visualizing the ureter itself, especially the mid-section, which is obscured by bowel gas. Therefore, it is often used as a screening tool or for monitoring, rather than definitive mapping.

Plain X-ray of the Kidneys, Ureters, and Bladder (KUB) is often used as an adjunct. However, its utility is limited because radiolucent stones (such as uric acid stones) are invisible on X-ray, and bowel gas or stool can obscure even calcified rocks. Its primary role is follow-up; if a stone is visible on the initial X-ray, subsequent X-rays can track its progress down the ureter without the need for repeat high-radiation CT scans.