Efficacy of unenhanced computed tomography features in distinguishing distal ureteric stones from phleboliths

The aim of this study is to evaluate the contribution of unenhanced computed tomography features in the differentiation of distal ureteric stones (DUS) from phleboliths. This retrospective study included 284 DUS and 116 phleboliths in 298 patients whose diagnosis were confirmed by ureteroscopy. The unenhanced computed tomography features of DUS and phlebolith were recorded, including volume, soft tissue rim, comet-tail sign, central lucency, shape, surface, density of pelvic calcifications and bladder volume. The differences between DUS and phlebolith in terms of mean volume and mean density were statistically significant (p<0.05). A peripheral rim was detected in 216 (80.3%) out of 269 DUS and in 8 (7.4%) of 108 phleboliths. The comet tail sign and central lucency had a 100% positive predictive value for the diagnosis of phleboliths. For the diagnosis of distal ureteral stones, the geometric shape and irregular surface had a 100% positive predictive value, while the smooth surface had a 100% negative predictive value. The contribution of increased bladder volume in the differentiation of phlebolites from distal ureter stones was significant (p<0.01). In the differentiation of distal ureteral stones from phlebolites, the comet tail sign, central lucency, geometric shape, irregular surface, and smooth surface can be used as predictive factors alone. In addition, volume, density, soft tissue rim, shape, and bladder volume are factors that can be used in the differentiation. Using all these features will be useful in daily practice.

Keywords: Distal ureteric stone, computed tomography, phlebolith