Unenhanced helical computed tomography in the evaluation of acute flank pain.

OBJECTIVE

The diagnostic value of unenhanced helical computed tomography (CT) for the evaluation of acute flank pain is investigated in a prospective study.

PATIENTS AND METHODS

In 125 patients aged 18-86 years, we performed unenhanced helical CT in addition to abdominal plain film, abdominal ultrasound and urinalysis as a diagnostic measure for acute flank pain. Ureteral calculi were confirmed or, respectively, excluded by retrograde ureteropyelography in 80 cases. In the other cases, diagnosis was verified by clinical course and/or stone asservation.

RESULTS

In 91 of 125 patients the flank pain was caused by a ureteral calculus. In 67 of 91 patients with urolithiasis, stones could be collected for analysis. Helical CT was able to precisely identify 90 ureteral calculi. Abdominal plain films led to 8 false-positive and 48 false-negative findings. Thus, sensitivity of plain radiography, ultrasound and urinalysis was 47, 11 and 84% with a specificity 76, 97 and 32%, respectively.

CONCLUSIONS

Unenhanced helical CT reaches a distinctively increased diagnostic value (sensitivity 99%, specificity 97%) in the evaluation of acute flank pain as compared to plain radiography, ultrasound and urinalysis.