CTA of the Abdomen and the Superior Mesenteric Artery
Yes, CTA of the abdomen will definitively show the superior mesenteric artery (SMA) with excellent accuracy—it is the gold standard imaging modality for evaluating the SMA and mesenteric vasculature.
Diagnostic Performance
CTA abdomen and pelvis demonstrates the SMA with sensitivity and specificity of 95% to 100% for detecting stenosis, occlusion, and other vascular pathology 1. This makes it the most accurate non-invasive imaging technique available for SMA evaluation 1.
What CTA Shows
CTA reliably visualizes the following SMA features:
- Origin and proximal segments: Atherosclerotic plaques, stenosis, and occlusions at the vessel origin are clearly depicted 1
- Embolic disease: Filling defects from emboli in the proximal SMA are readily identified 1
- Dissection and aneurysm: CTA accurately shows dissecting aneurysms, thrombosed false lumens, and intimal flaps 2
- Branch vessels: Distal SMA branches and their involvement in disease processes are visualized 3, 4
- Collateral circulation: Development of collateral vessels in chronic disease is assessable 5
Clinical Applications
Acute Mesenteric Ischemia
CTA abdomen and pelvis with IV contrast is the recommended initial imaging examination for suspected acute mesenteric ischemia 1. It detects:
- Superior mesenteric artery embolism or thrombosis 3, 6
- Early ischemic changes including poor arterial enhancement and venous dilatation 6
- Bowel wall abnormalities and complications 6
Chronic Mesenteric Ischemia
CTA provides the best accuracy and inter-reader agreement for grading mesenteric vessel stenosis compared to MRA and ultrasound 1. The American College of Radiology recommends CTA as the primary diagnostic modality to evaluate SMA stenosis and assess for multi-vessel involvement 5.
CTA demonstrates:
- SMA-origin stenosis with quantification of severity 1, 5
- Calcified and non-calcified atherosclerotic plaque 1
- Celiac artery and inferior mesenteric artery patency 1
- Median arcuate ligament compression 1
Technical Considerations
Optimal Imaging Protocol
- Arterial phase timing is critical for optimal SMA visualization 3
- Three-dimensional reconstruction enhances evaluation of vascular anatomy and pathology 3, 4
- Multidetector CT technology provides superior resolution for medium and small arterial structures 3, 4
Comparison to Other Modalities
CTA outperforms alternative imaging methods:
- Versus conventional angiography (DSA): CTA is non-invasive with comparable accuracy; DSA has transitioned to a complementary role with therapeutic intervention capability 1
- Versus MRA: CTA shows better inter-reader agreement and superior evaluation of distal branches 1
- Versus duplex ultrasound: CTA is not operator-dependent and provides comprehensive evaluation without bowel gas interference 1
Important Clinical Pitfalls
Do not confuse venous phase CT with CTA—standard CT abdomen with IV contrast performed during venous phase provides only satisfactory evaluation of major vascular pathology and may miss significant stenosis 1. Arterial phase timing is essential for accurate SMA assessment 3.
Non-contrast CT has no role in evaluating SMA pathology, as it cannot assess non-calcified plaque and will underestimate stenosis severity 1.