For centuries, bowel trauma had a high mortality rate, and survivors escaped death by withstanding hemorrhage and sepsis. With the introduction of radiography, diagnostic accuracy improved. Multi-row helical detector CT scans are capable of scanning the abdomen in less than 30 seconds and can detect free air, free fluid, abnormal bowel wall enhancement, bowel wall thickening, and mesenteric infiltration. These advances in CT have brought the debate of conservative management of abdominal trauma full circle. Currently, many patients with blunt abdominal trauma or retroperitoneal penetrating trauma can be managed without surgery and can avoid unnecessary laparotomy.
See the related images below.
A 47-year-old man with blunt trauma to the abdomen. Axial CT through upper abdomen reveals 2 spots of free intraperitoneal air (arrows).
Female patient with right-sided colon perforation. Axial CT through the abdomen shows focal gas bubbles (red arrow) and anextraluminal fluid collection (blue arrow) adjacent to the contrast-filled colon.
Multidetector CT scanning using 16- and 64-slice CT has increased the speed in which trauma patients are scanned. In addition, 16- and 64-slice multidetector CT imaging allows the creation of isotropic voxels that allow reformats to be performed in sagittal and coronal planes, which can allow better localization of bowel injuries.
CT of the abdomen is the preferred diagnostic examination for the evaluation of blunt abdominal trauma in the hemodynamically stable patient with blunt abdominal trauma and in selected instances of penetrating trauma to the posterior abdomen. Unstable patients or patients with penetrating injuries to the abdomen undergo exploratory laparotomy.
Abdominal CT examination should be systematic. Traumatic injury to the bowel is rarely isolated. First, evaluate the more commonly injured organs, such as the liver and spleen, as well as the pancreas, adrenals, kidneys, blood vessels, spine, and skeletal structures.
Evaluate traumatic injury to the bowel in the context of the mechanism and location of injury, as follows:
Right upper quadrant: examine the right lung base, right hemi-diaphragm, liver, gallbladder, right colon, right adrenal, right kidney, and right abdominal small bowel loops
Midline: evaluate the base of the heart, diaphragm, pancreas, duodenum, aorta, inferior vena cava, and small bowel mesentery
Left upper quadrant: evaluate the base of the heart, base of the left lung, left hemi-diaphragm, stomach, spleen, tail of the pancreas, left adrenal, left kidney, left colon, and small bowel loops
Lower abdomen and/or pelvis: evaluate the bladder, rectosigmoid, and small bowel loops.
Each imaging modality (eg, plain abdominal radiograph, US, CT) demonstrates typical findings that suggest a diagnosis of bowel trauma.
In the hemodynamically stable patient with abdominal trauma, CT is the study of choice.
Limitations of techniques
The accuracy of CT for the evaluation of bowel injury is as high as 97.6%.
CT can be limited if diagnostic peritoneal lavage (DPL) is performed prior to the CT. Free intraperitoneal fluid and air from the DPL observed on CT makes the evaluation for bowel injury very difficult.
Although CT can suggest bowel injury by demonstrating free intraperitoneal air, free fluid, or thickened bowel wall, in many instances it cannot reliably localize the exact location of bowel injury.
Delayed presentation of bowel injury occasionally occurs. Patients returning with continued symptoms several hours or days after a negative trauma should undergo repeat CT.