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.