Imaging in renal trauma

Abstract

Renal injuries are classified, based on the American Association for the Surgery of Trauma classification, in to five grades of injury. Several imaging modalities have been available for assessing the grade of renal injury, each with their usefulness and limitations. Currently, plain radiographs and intravenous urography have no role in the evaluation of patients with suspected renal injury. Ultrasonography (USG) has a limited role in evaluating patients with suspected retroperitoneal injury; however, it plays an important role during follow up in patients with urinoma formation. USG helps to monitor the size of a urinoma and also for the drainage procedure. The role of selective renal arteriography is mainly limited to an interventional purpose rather than for diagnostic utility. Retrograde pyelography is useful in assessing ureteral and renal pelvis integrity in suspected ureteropelvic junction injury and for an interventional purpose, like placing a stent across the site of ureteric injury. Magnetic resonance imaging has no role in acute renal injuries. Multidetector computed tomography is the modality of choice in the evaluation of renal injuries. It is also useful in evaluating traumatic injuries to kidneys with preexisting abnormalities and can help to define the extent of penetrating injuries in patients with stab wounds in the flank region. The combination of imaging findings along with clinical information is important in the management of the individual patient. This article will describe a spectrum of renal injuries encountered in a trauma setting.

Keywords: Trauma; Renal injury; Imaging; Focused abdominal sonography for trauma; Multidetector computed tomography; Contrast-enhanced computed tomography; Grading; American Association for the Surgery of Trauma classification; Vascular injury; Revision of American Association for the Surgery of Trauma

Core tip: Renal trauma is frequently seen following blunt and penetrating injuries. Surgery, as a method of treatment, is frequently required in severe injuries, with most minor injuries managed conservatively. Apart from the surgical grading by the American Association, an imaging-based grading system is now frequently used and helps to decide further management. Multidetector computed tomography is now the imaging modality of choice and can depict even the severest injuries. Depending upon the imaging findings, patients may be taken for interventional procedures rather than surgery. The American Association for the Surgery of Trauma classification has been updated, with vascular injuries now included, denoting a Grade V injury.