Secondary signs during non-enhanced helical computed tomography in the diagnosis of ureteral stones

Nonenhanced helical computed tomography (NHCT) is a well-accepted diagnostic method for examining patients with suspected ureterolithiasis. NHCT shows stones within the lumen of the ureter, and it can also be used to evaluate secondary signs associated with ureteral obstruction from stones. Secondary signs include the tissue rim sign, hydroureter, perirenal stranding, and renal density differences between affected and nonaffected kidneys. Identification of secondary signs can help diagnose ureteral stones and contributes to the evaluation of ureteral obstruction.