On non-contrast CT, there are bilateral hypodensity on both renal sinuses, larger on left kidney, with normal caliber of both ureters. Bilateral renal concretions are noted, largest at left upper calyx.
In excretory phase, there are non-enhancing fluid-density cysts intimately related to and encircling renal calyces and stretching infundibula with mild dilatation due to partial obstruction. This is more prominent on left kidney.