The Value of Non-Enhanced Spiral CT in the Diagnosis of Suspected Urolithiasis / 대한비뇨기과학회지

ABSTRACT

PURPOSE: We prospectively determined the value of a non-enhanced spiral CT (NESCT) in the diagnosis of suspected urolithiasis by a comparison with excretory urography (EU). MATERIALS AND METHODS: After giving informed consents, 114 and 103 patients, with suspected urolithiasis, underwent either NESCT or EU, respectively. All the NESCT and EU films were assessed by 2 urologists and 1 radiologist with no knowledge of the clinical histories. The sensitivity, specificity, positive and negative predictive value, diagnostic accuracy and other valuable diagnostics in each group were compared. RESULTS: The sensitivity, specificity and accuracy of NESCT in diagnosing urinary calculi were 96.8, 95.2 and 96.5%, and for EU, were 75.3, 90.9 and 78.6%, respectively. The examinations were performed with an average of less than 5 minutes for the NESCT versus 113+/-31 minutes for the EU, and the times taken to a definitive diagnosis in the two groups were 2.4+/-0.3 and 59+/-5.2 hours, respectively. In the EU group, 24 patients (23.3%) had revisited and 11 (10.6%) were admitted for pain control, prior to the imaging evaluation, only 2 patients (1.7%) revisited, and none were admitted in the NESCT group. In our institution, the cost of a NESCT was more expensive than that of an EU (140,000 vs. 35,790 Won), however the cost-effectiveness is enhanced by the accuracy of NESCT, which lead to fewer ancillary studies. CONCLUSIONS: NESCT is accurate, reliable and safe, and has many advantages over EU, and therefore could be recommended as a first diagnostic modality for the evaluation of patients with suspected urolithiasis.