Aorta and illiac arteries

Objectives

  • Identify characteristics of a complete aortoiliac duplex imaging exam.
  • Define aortic and iliac aneurysms.
  • Importance of orthogonal orientation in aneurysm measurement.
  • Key characteristics for evaluating iliac stents.
  • Frequent complications with aortic endograft repair (EVAR).
  • Four types of endoleaks and their frequencies.

Background

  • Color duplex ultrasonography (CDU) is essential for evaluating the aorta and iliac arteries.
  • CDU detects abdominal aortic aneurysms with excellent correlation to arteriography.
  • Noninvasive and well-tolerated by patients.

Sonographic Examination Techniques

  • Indications for aortoiliac duplex exam include: pulsatile abdominal mass, known/ suspected aneurysm, claudication, and follow-up after intervention.
  • Patients should fast for optimal imaging.
  • Positioning is typically supine with the head elevated.

Scanning Technique

AAA Protocol
  • Exam includes both transverse and sagittal planes of the aorta and iliac arteries.
  • Diameter measured at proximal aorta, mid-aorta, and distal aorta.
  • Care must be taken for proper measurement angles.
  • Evaluate aneurysm length, proximity to renal arteries, thrombus presence, etc.
Postintervention Protocol
  • Follow-up is essential for detecting restenosis and complications post-EVAR.
  • Evaluate stents for alignment, deployment, and vessel wall relationship.
  • Typical procedures include Doppler measurements through various segments of the treatment area.

Diagnosis

  • Normal findings: aortic diameter <2 cm; tapering aorta profile; high-resistance Doppler signals.
  • AAA considered when diameter >3 cm or >50% increase compared to a normal segment.
  • Aneurysms may be fusiform or saccular.
  • complications of aneurysms include rupture and hydronephrosis.

EVAR

  • EVAR is less invasive for AAA repair and associated with improved survival rates.
  • Requires close follow-up to monitor endoleaks, stent kinking, and migration risks.
  • Types of endoleaks identified include types I-IV.

Technical Considerations

  • Address challenges posed by bowel gas, obesity, and vessel tortuosity.
  • Use proper Doppler techniques for accurate assessments and identify complications.

Key Takeaways

  • Aortoiliac duplex ultrasound is a critical evaluation tool for vascular conditions, especially for monitoring AAAs and related interventions.