Abdominal CT: renal, ureter, and adrenal injury
Diagnosing renal injuries
Renal injuries follow a similar pattern to those in the spleen and liver.
Kidney lacerations
There can be relatively small lacerations or hematomas involving the cortex
Larger and deeper lacerations can injure the vasculature and result in active bleeding and retroperitoneal bleeding.
Shattered kidney and devascularization
Severe trauma can result in a shattered kidney, where the tissue becomes extensively injured and disrupted. When the injury extends to the hilum, there is potential for a vascular injury resulting in devascularization of portions of the kidney.
In the example below, there is absent enhancement of several segments of the kidney due to tissue and vascular injury, and these injured segments blend in with the surrounding perinephric blood.
Subcapsular hematoma
Sometimes blood from a renal injury accumulates under the renal capsule. This is called a subcapsular hematoma. You can recognize these by how they compress and distort the kidney shape compared to the uninjured kidney.
A large subcapsular hematoma compresses the underlying tissue, resulting in increased pressure on the kidney and impaired perfusion. Look at the compressed left kidney in our next CT image and notice that there is less enhancement and the cortex and medulla appear distinct from each other. Compare this to the normal right kidney which has uniform bright enhancement throughout.
Deceleration injury
Deceleration injury is a type of blunt trauma that occurs when a rapidly moving person is suddenly brought to a halt. These injuries can stretch the renal hilum where the vessels, nerves, and ureter enter the kidney. This can result in a traumatic dissection of the artery and result in multiple infarcts that look like peripheral, wedge-shaped defects.
Diagnosing ureter injuries
In severe renal trauma, you must also evaluate the ureter for injuries. Traumatic ureteral injury can result in a urine leak around the kidney and may be an indication for ureteral stenting or surgical repair.
When the initial scan shows a kidney injury, delayed images allow time for the kidneys to form contrast-opacified urine, similar to a urogram. In the case shown next, the patient had a smaller cortical laceration and blood surrounding the kidney.
The next image from the same patient is at the level of the renal hilum. It shows more blood has leaked around the kidney from the small laceration seen in the previous image. You can also see that the renal pelvis is a bit dilated and there is dense material within it, suggesting some blood clots. This finding raises the concern of a collecting system injury.
Delayed images obtained at 8 minutes allowed the kidney to produce contrast-enhanced urine. Notice how a thin layer of contrast leaks out and surrounds the kidney, indicating that the collecting system is injured.
Diagnosing adrenal injuries
Adrenal injuries occur with severe blunt trauma to the abdomen.
The right adrenal gland is more commonly injured. This is because blunt force to the liver will compress the right adrenal into the vertebral bodies, resulting in a crush-type injury. Left adrenal injury is much less common.
Injury to the adrenal gland can appear in several different ways on CT imaging. In this first case, there is decreased or interrupted enhancement of the right adrenal gland, indicating injury and haematoma.
In this second example, there are several small areas of active bleeding surrounding the haemorrhagic adrenal gland.
Adrenal injury can also appear as ill-defined blood products with loss of a visible gland, or the adrenal gland can appear as a round mass.
This is an edited excerpt from the Medmastery course Abdomen CT: Trauma by Michael P. Hartung, MD. Acknowledgement and attribution to Medmastery for providing course transcripts
- Hartung MP. Abdominal CT: Common Pathologies. Medmastery
- Hartung MP. Abdominal CT: Essentials. Medmastery
- Hartung MP. Abdomen CT: Trauma. Medmastery
References
- Top 100 CT scan quiz. LITFL
Radiology Library: Abdominal Trauma. Solid organ injury
- Hartung MP. Abdominal Trauma: solid organ injuries
- Hartung MP. Abdominal Trauma: spleen, liver, and pancreas injury
- Hartung MP. Abdominal Trauma: renal, ureter, and adrenal injury
- Hartung MP. Abdominal Trauma: solid organ injury [case study]
Abdominal CT interpretation
Assistant Professor of Abdominal Imaging and Intervention at the University of Wisconsin Madison School of Medicine and Public Health. Interests include resident and medical student education, incorporating the latest technology for teaching radiology. I am also active as a volunteer teleradiologist for hospitals in Peru and Kenya. | Medmastery | Radiopaedia | Website | Twitter | LinkedIn | Scopus
MBChB (hons), BMedSci - University of Edinburgh. Living the good life in emergency medicine down under. Interested in medical imaging and physiology. Love hiking, cycling and the great outdoors.