Obtain a urinalysis in all patients with multisystem trauma or suspected isolated renal injury Management/Diagnostic Testing Hemodynamically stable patients who present with suggestive clinical findings, gross hematuria, microscopic hematuria of more than 50 RBCs/hpf, major associated injuries, or a history of significant deceleration injury should undergo radiographic evaluation Obtain a contrast-enhanced CT scan with delayed images Children who remain unstable despite resuscitative measures should undergo a one-shot IVP before emergency laparotomy Children with isolated microscopic hematuria of less than 50 RBCs/hpf not require immediate imaging These patients may be discharged and can be evaluated on an outpatient basis with CT, IVP, or ultrasound if hematuria persists However, in some pediatric trauma centers, management of these patients involves hospitalization for observation, followed by nonemergent radiographic evaluation The diagnostic performance of imaging modalities as they relate to the evaluation of renal trauma is reviewed below: Computed Tomography Contrast-enhanced CT with additional 10-minute delayed scan is the “gold standard” imaging modality for staging a stable trauma patient The delayed scan or “excretory” phase, occurs after contrast has passed into the renal pelvis and ureter, allowing better definition and evaluation of these structures Trauma patients lacking radiographic signs of renal injury who not have any perinephric, periureteral, or pelvic fluid collections not require delayed imaging per expert consensus If any of these subtle findings, especially lowdensity fluid tracking around the kidney and down the ureter, are present on the initial contrast-enhanced CT, delayed scan is indicated A UPJ or a ureteral injury can easily be missed if delayed images are not obtained The diagnostic accuracy of CT scan has been reported to be as high as 98% ( Fig 108.3 ) The ability of CT to quickly evaluate solid organ and vascular injuries has significantly improved the management of trauma Important radiologic findings that should be noted when reviewing CT for renal trauma include arterial medial extravasation of contrast, denoting a severe arterial injury; medial hematoma without arterial extravasation, often secondary to a venous injury; differential contrast uptake and excretion, which is indicative of arterial injury or thrombosis; cortical rim sign, often indicative of a main renal artery injury; degree of parenchymal laceration and involvement of the collecting system; degree of