The Relationship between Ureteral Obstruction Time and Secondary Signs in Computed Tomography due to Ureteral Stone Obstruction.

Objective: To investigate the relationship between numerical values obtained using computed tomography (CT) in stone-related urinary obstruction and the duration of obstruction.

Study Design: Cross-sectional study.

Place And Duration Of Study: Department of Urology, Alanya Alaaddin Keykubat University, Turkey, from January 2018 to September 2019.

Methodology: Eighty-three patients were investigated. Commencement of obstruction was defined as time of onset of pain. Cases with less than seven days elapsed between onset of obstruction; and CT were classified as acute obstruction; and those with durations of seven days or more as chronic obstruction. Bilateral renal parenchymal and renal fatty tissue densities were measured in three planes.

Results: Acute obstruction was present in 53 patients and chronic obstruction in 30. Median renal parenchymal densities in the obstructive and non-obstructive kidneys were 33 and 37 Hounsfield unit (HU), respectively; and median perirenal densities were 99 and 108 HU, the differences being statistically significant (p <0.05). Median perirenal density were 96 HU in acute obstruction and 104.5 HU in chronic obstruction and the difference was statistically significant (p <0.05). No statistically significant difference was determined between renal parenchymal density in acute and chronic obstruction (p >0.05).

Conclusions: A low perirenal density on CT indicated prolonged duration of urinary obstruction.  Key Words: Computed tomography, Hounsfield unit, Kidney stone, Ureter, Ureteral stone.