renal forniceal rupture
Renal forniceal or calyceal rupture is the radiographic finding of a perirenal urine leak as a result of ureteric obstruction.
The renal fornices are the thin pointed projections, arising from the lateral aspects of each minor calyx, and extending a short distance into the renal columns. Each fornix contacts the renal pyramid on its inner surface.
The renal fornix is the most susceptible part of the renal collecting system to rupture from increased pressure .
Causes include :
- ureteric calculus (~75%)
- extrinsic compression
- benign, e.g. pregnancy
- intrinsic obstruction, e.g. hematoma, tumor
- posterior urethral valves
- pelviureteric junction obstruction
On non-contrast CT, perinephric low-density fluid and fat stranding will be present. On delayed phase imaging contrast will accumulate outside of the collecting system forming a urinoma .