Black kidney sign: a new computed tomographic finding associated with the hypoperfusion complex in children.

The authors describe a new CT finding associated with the hypoperfusion complex in children: complete lack of enhancement of both kidneys without renal swelling, without subcapsular cortical rim enhancement, and without peripheral wedge-shaped areas of hypoattenuation. This "black kidney sign" was found in two severely injured children who died within a few hours after the CT examination. It may help to establish a diagnosis of severe hemodynamic instability and may be a negative prognostic factor.