Comparison of kidney densities of cases with urinary dilatation in unenhanced CT scan

Purpose
The aim of this study was to investigate the diagnostic value of renal parenchymal density differences in distinguishing between acute and chronic urinary dilatations.

Material and methods
Retrospectively, unenhanced CTs of 98 patients were evaluated. Thirty-three had acute urinary obstruction, and 33 had chronic urinary obstruction. Parenchymal density values (HU) and renal pelvic anterior-posterior (AP) diameters of all groups were evaluated by two different radiologists who were unaware of each other and the content of the study. The t-test was used to compare parenchymal densities and renal pelvic diameter differences with normal, acute urinary dilation and chronic urinary dilation groups.

Results
Of the 98 cases who were included in the study, 33 people were in the acute obstruction group (7 females, 26 males), and 33 were in the chronic obstruction group. However, the second observer (observer 2) found a statistically significant difference (p < 0.01) during the measurements of density between the obstructed and normal sides. While for the first observer (observer 1), the correlation between right and left renal density measurements of the normal cases was moderate at 0.576; correlation of measurements done by the second observer was found to be high at 0.777.

Conclusions
Pale kidney findings seems to be helpful in diagnosis of acute urinary occlusion, but different results are obtained with evaluations made by different observers. Moreover, it is not a specific finding because oedema can also be seen in some other conditions, such as acute pyelonephritis; for this reason, one must be careful during the evaluation of this finding.