URETEROLITHIASIS - CAN CLINICAL OUTCOME BE PREDICTED WITH UNENHANCED HELICAL CT

PURPOSE: To evaluate the use of helical computed tomography (CT) witho ut contrast material enhancement for prediction of a favorable outcome in ureterolithiasis. MATERIALS AND METHODS: CT studies were reviewed in 69 patients with a single ureteral stone not located at the uretero pelvic junction. CT findings (tissue rim sign, hydronephrosis, perinep hric fat stranding, perinephric fluid collections, and thickening of r enal fascia) were graded on a scale of 0-3. Stone-diameter and renal p arenchymal enlargement were also measured. RESULTS: Twenty-two patient s had spontaneous passage, 12 did not respond: to conservative treatme nt, and 35 were lost to follow-up. When the latter 35 patients were ex cluded, perinephric fat stranding (P = .044) and perinephric fluid col lections (P = .021) were graded significantly higher in patients with spontaneous stone passage. Mean stone diameter was significantly large r (P < .001) in patients in whom conservative treatment failed (mean, 7.8 mm) than inpatients with spontaneous stone passage (mean, 2.9 mm). The presence of a tissue rim sign and the grade of hydronephrosis, re nal fascial thickening, and:renal parenchymal enlargement were not sig nificantly different between the two groups. CONCLUSION: In addition t o stone size, the degree of perinephric fat stranding and the presence of perinephric fluid collections are useful ancillary signs for::help in predicting the likelihood of stone passage.