A comparison of noncontrast computerized tomography with excretory urography in the assessment of acute flank pain.

PURPOSE: We compare noncontrast enhanced computerized tomography (CT) and excretory urography (IVP) in the evaluation of acute flank pain.

MATERIALS AND METHODS: A total of 40 consecutive patients presenting to the emergency department with acute flank pain were evaluated with noncontrast CT, films of the kidneys, ureters and bladder, and IVP. The patients were treated according to the clinical picture. All 40 sets of evaluations were later assessed randomly by an independent consultant radiologist for the presence, size and location of a stone, ureteral dilatation and secondary signs of ureteral obstruction.

RESULTS: Of 40 patients 12 had no calculus and 28 had a calculus confirmed on removal or documented passage of a stone. Absence of a stone was based on clinical and radiological followup with clinical resolution. CT revealed all 28 calculi and no calculus in 11 of 12 patients with 100% sensitivity and 92% specificity. IVP demonstrated 18 calculi (64% sensitivity) and no calculus in 11 of 12 patients (92% specificity). Ureteral obstruction was seen in 28 of the 40 patients, and CT and IVP were equivalent in detection (100% sensitivity). Films of the kidneys, ureters and bladder alone demonstrated 15 of 28 stones (54% sensitivity).

CONCLUSIONS: Noncontrast CT is an accurate, safe, rapid technique to assess acute flank pain, and the evaluation of choice for patients who would otherwise require IVP for diagnosis.