The primary goal of imaging in patients with acute kidney injury (AKI) is differentiating obstructive (pre-renal and post-renal) from nonobstructive (primary renal) causes.
Basic tenets of managing AKI are first provided adequate renal perfusion and second identify and relieve obstructions to urine flow. Ultrasonography is an excellent diagnostic tool for patients with rising serum creatinine or oliguria unresponsive to plasma volume expansion. Clinical factors should guide imaging studies including anatomy at-risk in the surgical field, anesthetic techniques, blood loss, intravascular volume status, preexisting conditions, and patient demographics. Toxic nephropathy should be suspected as it is more common than direct injuries. Computed tomography and MRI are more comprehensive modalities but have some limitations.