From the Guidelines
Triple phase CT angiography (CTA) of the abdomen refers to imaging performed at three distinct time points after contrast administration: non-contrast, arterial, and portal venous phases, which is crucial for identifying the underlying cause of mesenteric ischemia and evaluating for possible bowel complications. For suspected mesenteric ischemia, this approach is particularly valuable as it allows comprehensive evaluation of the mesenteric vasculature 1. The non-contrast phase helps detect vascular calcification, hyper-attenuating intravascular thrombus, and intramural hemorrhage, while the arterial phase captures the early contrast filling of arteries, which is crucial for identifying arterial occlusions or stenoses that may cause acute mesenteric ischemia. The portal venous phase shows contrast in the portal and mesenteric veins, helping detect venous thrombosis that could lead to venous mesenteric ischemia.
- This multi-phase approach increases diagnostic accuracy by providing a complete picture of blood flow through the mesenteric circulation, allowing differentiation between arterial and venous causes of ischemia, and revealing secondary signs of bowel compromise such as pneumatosis intestinalis or portal venous gas 1.
- The use of CTA is strongly recommended in patients with suspected acute mesenteric ischemia, as it has been shown to have high sensitivity and specificity for diagnosing the condition, and can help guide treatment decisions 1.
- It is essential to perform CTA without delay in patients with suspected mesenteric ischemia, as delays in diagnosis can lead to increased mortality rates 1.
- The patient should be well-hydrated and follow any specific preparation instructions provided by the radiology department to ensure optimal results.
- 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.
From the Research
Triple Phase CTA
- Triple phase CTA refers to a computed tomography angiography (CTA) scan that is performed in three phases: arterial, portal venous, and delayed phase 2, 3, 4.
- The arterial phase is used to evaluate the arterial supply to the bowel, while the portal venous phase is used to assess the venous drainage 2, 3.
- The delayed phase is used to evaluate the bowel wall and detect any signs of ischemia or infarction 4.
Diagnosis of Mesenteric Ischemia
- CTA is a key diagnostic tool for mesenteric ischemia, and triple phase CTA is often used to evaluate patients with suspected mesenteric ischemia 2, 3, 4.
- The use of intravenous contrast enhancement and imaging in the arterial and/or portal venous phase can help diagnose acute mesenteric ischemia in the early stages 2, 3.
- A high index of suspicion is key for early diagnosis, and a triphasic computed tomography angiography is the essential diagnostic tool 4.
Treatment Options
- Treatment options for mesenteric ischemia include endovascular recanalization and stenting, aspiration embolectomy, thrombolysis, and open surgical embolectomy 2, 3, 5.
- Endovascular therapy may be an option in patients with mesenteric venous thrombosis who do not respond to anticoagulation therapy 2, 3, 5.
- Laparotomy is needed to evaluate the extent and severity of visceral organ ischemia, which is treated according to the principles of damage control surgery 2, 3.