Submucosal edema of the collecting system: a new ultrasonic sign of severe, acute renal allograft rejection. A clinical note.

Parenchymal edema is one of the patho-physiological results of the renal allograft rejection process. We report three instances of edema visualized within the renal pelvis at the clinical peak of acute rejection, representing a late, but highly specific, sign of this condition. Its occurrence does not imply clinical irreversibility.