The kidney is the most commonly injured genitourinary organ. The diagnosis and treatment depend on the mechanism of injury (blunt or penetrating trauma), the clinical presentation, and the extent of the lesions. Knowledge of the different appearances of the posttraumatic kidney on imaging studies is essential for prompt and effective treatment of patients. This pictorial essay reviews the imaging evaluation and principal imaging findings associated with blunt and penetrating renal trauma. The role of computed tomography is emphasized because it is a very sensitive, specific, and accurate modality in detecting the presence or absence of injury and defining its extent.
Renal injury is a common feature of major abdominal trauma, occurring in 8-10% of all blunt and penetrating injuries [1]. Blunt injuries account for approximately 80% of all cases of renal trauma [2] and more frequently involve the left kidney. Injury can occur as a result of direct blows or deceleration. Rapid deceleration has been associated with a high incidence of renal pedicle injuries and ureteropelvic junction disruption [3]. Predisposing factors such as ureteropelvic junction and other causes of chronic hydronephrosis, horseshoe kidney and ectopia, cancer and polycystic diseases make the kidney more vulnerable. Penetrating injuries are due mostly to gunshot or stab wounds [2] and often require surgery. Iatrogenic injuries are an important subgroup of renal trauma. Percutaneous nephrostomy, renal biopsy, and extracorporeal shock wave lithotripsy can produce a spectrum of renal injury including hematomas and distal vascular lesions [3-5].
The management of renal injuries is controversial. The diagnosis and treatment of renal trauma depend on the mechanism of injury, the age of the patient, and the clinical manifestations. Prompt and accurate evaluation of the type and extent of trauma is essential for appropriate management.
The purpose of this pictorial essay is to present a spectrum of diagnostic imaging findings in patients with renal trauma and to underline the role of spiral computed tomography (CT) in the grading of renal injury.