Unilateral acute renal cortical necrosis - Correlative imaging

Bilateral acute cortical necrosis is a rare form of acute renal failure cha racterized by necrosis of the renal cortex and sparing of the medulla. Litt le information on the imaging presentation of bilateral acute renal cortica l necrosis is available. The enhanced CT appearance is pathognomonic and di agnostic. The unilateral presentation of acute cortical necrosis is extreme ly rare, and no imaging methods have been described. The authors chose to a pply scintigraphic evaluation to this unique condition complementary to CT to confirm the diagnosis. Mercaptoacetylglycine (T3) was selected to assess tubular damage, in contrast to the pure glomerular agent DTPA. Evidence of some tubular function and clear delineation of the shrunken kidney was fou nd. Conversely, in the DTPA study the kidney was not visualized. A DMSA sca n was performed for assessment of viability of the renal cortex and showed a photopenic halo around the small area of the viable cortex of the upper p ole. The halo sign represents a cortical loss. The visualization of the upp er pole as evidence of cortical viability as a consequence of collateral bl ood flow from capsular vessels was seen on angiography. Radiographic and sc intigraphic correlation of this rare condition may be an effective means to confirm the diagnosis and to establish the extent of involvement. However, contrast CT remains the preferred method in the diagnosis of acute cortica l necrosis.