A 42-year old male patient presented with the complaints of right lumbar pain, high-grade fever, burning micturition and pyuria for past 4 days. He was diagnosed with a liver abscess which had ruptured into the superior pole of right kidney.

Objective: To evaluate the usefulness of non-enhanced spiral CT (NECT) and compare it with that of excretory urography (EU) in patients with acute flank pain. Methods: Ninety five patients presenting with acute flank pain underwent both NECT and EU. Both techniques were used to determine the presence, size, and location of urinary stone, and the presence or absence of secondary signs was also evaluated. The existence of ureteral stone was confirmed by its removal or spontaneous passage during follow-up. The absence of a stone was determined on the basis of the clinical and radiological evidence. Result: Seventy eight of the 95 patients had one or more ureteral stones and 17 had no stones. CT depicted 79 of 83 calculi in the 78 patients with a stone and no calculus in all seventeen without a stone. The sensitivity and specificity of NECT were 95% and 100%, respectively. EU disclosed 73 calculi in the 78patients with a stone and no calculus in fifteen of the seventeen without a stone, with sensitivity and specificity 89% and 88% respectively. Conclusion: For the evaluation of patients with acute flank pain, NECT is an excellent modality with high sensitivity and specificity. In near future it may replace EU.