What is the best imaging modality to evaluate a splenic artery aneurysm (SAA) or pseudoaneurysm?

Best Imaging for Evaluation of Splenic Artery Aneurysm/Pseudoaneurysm

Contrast-enhanced CT scan is the gold standard for evaluation of splenic artery aneurysm (SAA) or pseudoaneurysm in hemodynamically stable patients. 1

Initial Diagnostic Approach

The choice of diagnostic technique must be based on the hemodynamic status of the patient:

• For hemodynamically unstable patients:

  • E-FAST (Extended Focused Assessment with Sonography for Trauma) is effective and rapid to detect free fluid 1
  • Bedside ultrasound may have utility when patients cannot undergo CT 1

• For hemodynamically stable patients:

  • Contrast-enhanced CT scan with intravenous contrast is the gold standard with sensitivity and specificity approaching 96-100% for splenic injuries 1
  • CT angiography (MDCTA) allows detailed visualization of vascular anatomy and can identify both aneurysms and pseudoaneurysms 2
  • Delayed-phase CT helps differentiate patients with active bleeding from those with contained vascular injuries 1

Advanced Imaging Options

• Doppler Ultrasound (DUS) and Contrast-Enhanced Ultrasound (CEUS):

  • Useful to evaluate splenic vascularization and in follow-up 1
  • Effective in evaluating pseudoaneurysms or blush previously found on CT scan 1
  • Can increase sensitivity for evaluation of splenic flow and injuries 1
  • May allow avoidance of CT scan in patients with low clinical suspicion 1

• Digital Subtraction Angiography (DSA):

  • Remains the gold standard for demonstration of high-flow vascular anomalies and aneurysms 1
  • Provides both diagnostic information and opportunity for therapeutic intervention 3
  • Associated with a low incidence of procedural complications 1

Imaging Considerations for SAA vs. Pseudoaneurysm

• CT angiography allows differentiation between true aneurysms and pseudoaneurysms 2, 4

  • True aneurysms involve all three arterial wall layers
  • Pseudoaneurysms involve only one or two layers 5

• CT findings to evaluate:

  • Size of aneurysm (treatment recommended for lesions ≥2 cm) 5
  • Presence of active extravasation
  • Relationship to surrounding structures
  • Potential communication with other organs (rare complication) 6

Follow-up Imaging

• Doppler US and contrast-enhanced US are useful for follow-up after treatment 1
• Post-embolization imaging is recommended to ensure obliteration of the aneurysm 3

Pitfalls and Caveats

• CT scan may underestimate splenic injuries at the hilum 1
• Ultrasound has reported false-negative rates of up to 42%, particularly when no significant extravasation is present or with injuries near the diaphragm 1
• CT must only be performed in hemodynamically stable patients or those responding to fluid resuscitation 1
• In centers with fast-track CT capabilities, criteria for performing CT in trauma patients may be expanded 1