Abdomen

Discussion

63-year-old male presented with left flank pain and decreased renal function (creatinine: 3.9 mg/dl, GFR: 15 ml/min).

Characterization of ureteral stone

Axial and coronal images

Conventional non-contrast/renal colic protocol CT scan showed a calcification along the course of left proximal ureter. Low atomic number of stone in Z effective images (6.91) and removal of stone in uric acid suppressed images were indicative of uric acid stone. The patient had type 2 diabetes as a risk factor with low urine pH of 5, and urinary alkalinization was prescribed. Double J stent was placed. Follow up CT one month later showed disappearance of the stone.

Urinary tract stone composition could be characterized quantitatively with Z effective images and also with the help of uric acid suppressed and uric acid only images. Identification of stone composition is important to determine the appropriate therapy option.

History

Benefits or pitfalls of dual-energy CT

Key images Findings