Unenhanced spiral CT in acute ureteral colic: a replacement for excretory urography?

Abstract

Objective: To compare the usefulness of unenhanced spiral CT (UCT) with that of excretory urography (EU) in patients with acute flank pain.

Materials and methods: Thirty patients presenting with acute flank pain underwent both UCT 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.

Results: Twenty-one of the 30 patients had one or more ureteral stones and nine had no stone. CT depicted 22 of 23 calculi in the 21 patients with a stone, and no calculus in all nine without a stone. The sensitivity and specificity of UCT were 96% and 100%, respectively. EU disclosed 14 calculi in the 21 patients with a stone and no calculus in eight of the nine without a stone. UCT and EU demonstrated secondary signs of ureterolithiasis in 15 and 17 patients, respectively.

Conclusion: For the evaluation of patients with acute flank pain, UCT is an excellent modality with high sensitivity and specificity. In near future it may replace EU.

Fig. 1

A 43-year-old patient with acute flank pain. A, B. Transaxial scans through the kidneys and bladder, respectively. Dilatation of the left renal pelvis (arrow in A) and a left distal ureter stone (arrow in B) are seen. Arrowhead: right renal calyceal stone.

Fig. 2

A 46-year-old man with acute flank pain. A transaxial CT scan through the lower poles of the kidneys demonstrates soft tissue rim sign around the ureter stone (black arrow) and periureteral strand in adjacent fat tissue (white arrows).

Fig. 3

A 57-year-old woman with acute right flank pain. A: EU; B, C: Transaxial UCT scans through the kidneys and bladder. A dense delayed nephrogram is seen in A, but the entire EU study revealed no stone shadow. On UCT a tiny stone at the right ureterovesical junction (arrow in C) is seen along with dilatation of the renal pelvocalyceal system (arrows in B).

Fig. 4

A 45-year-old male patient with acute flank pain. A: EU; B, C: UCT. Two separate stones (arrows) are demonstrated in the left proximal ureter in A, but on UCT (B, C) they are seen as one elongated stone. UCT (C), however, demonstrates small renal stones (arrowheads), not seen in A, at the lower pole of the left kidney.

Fig. 5

A 53-year-old man with acute flank pain. A: EU; B, C: Two consecutive CT scans of the pelvis. A single stone is seen in the left distal ureter in A; UCT, however, clearly demonstrates two separate distal ureter stones (white arrows) in B and C. The smaller stone in the more distal ureter, seen in C, is obscured in A.

Fig. 6

Incidentally discovered transitional cell carcinoma of the left kidney (arrows) in a 72-year-old man who presented with acute flank pain and hematuria.