From the Guidelines
A CTA of the abdomen shows detailed images of the abdominal blood vessels and surrounding organs, including the aorta and its branches, portal venous system, and major veins, as well as abdominal organs such as the liver, spleen, pancreas, kidneys, adrenal glands, and intestines, providing valuable information for diagnosing vascular diseases, planning surgeries, evaluating trauma, and monitoring known conditions 1.
Key Findings
- CTA is a fast, accurate, and noninvasive diagnostic tool for evaluating the bowel and assessing intestinal vasculature, and should be the first-step imaging approach in patients with acute bowel ischemia 1.
- The scan can reveal conditions such as aneurysms, blockages, tumors, bleeding, or vascular malformations, and provides cross-sectional images with excellent detail of both vascular structures and soft tissues.
- CTA can be helpful in stratifying patients to identify those who would benefit from angiography as opposed to those who should undergo emergent surgery, and grading the degree of arterial stenosis with CTA has been shown to be highly accurate compared to digital subtraction imaging (DSA) as well as other imaging modalities, including US and MRA 1.
Imaging Protocol
- Comprehensive biphasic CTA includes pre-contrast scans, arterial and venous phases, and multiplanar reconstructions (MPR) to assess the origin of the mesenteric arteries 1.
- Oral contrast is not indicated and may even be harmful, and CTA should be performed despite the presence of acute kidney injury, as the consequences of delayed or missed diagnosis are far more detrimental for patients than exposure to the iodinated contrast agent 1.
Clinical Significance
- CTA is an accurate technique for acute mesenteric ischemia diagnosis, with reported sensitivity and specificity as high as 93% to 100%, and potential to improve patient survival 1.
- Six radiological findings (bowel loop dilatation, pneumatosis intestinalis, SMV thrombosis, free intraperitoneal fluid, portal vein thrombosis, and splenic vein thrombosis) were found to be predictors of bowel necrosis in patients with AMI 1.
- CTA can demonstrate bowel ischemia and free fluid in the face of patent mesenteric vessels in non-occlusive mesenteric ischemia (NOMI), and thrombus in the superior mesenteric vein described as the target sign in mesenteric venous thrombosis (MVT) 1.
From the Research
Computed Tomography Angiography (CTA) of the Abdomen
- A CTA of the abdomen can show various abdominal and pelvic injuries, including splenic, hepatic, renal, and pancreatic injuries 2, 3, 4, 5
- It can also detect substantial abdominal or retroperitoneal injuries, such as hemoperitoneum and hollow viscus injuries 2, 3, 5
- CTA can be used to guide nonoperative management of hepatic and splenic trauma, and can detect vessel injury, active bleeding, or hemobilia 3
- The accuracy of CTA in detecting abdominal injuries is high, with a reported accuracy of more than 95% for hepatic and splenic injuries 3
- CTA can also be used to detect minor injuries that do not require laparotomy, and can reliably diagnose patients with acute pancreatic injuries 5
- The use of CTA in conjunction with clinical monitoring can be reliable in the evaluation of blunt abdominal trauma in selected patients 5