Abdominal aorta aneurysm

Clinical:

  • A 70 years old man
  • No known medical problem
  • A smoker
  • Presented with abdominal mass for one year
  • Dizziness for 3 days
  • Went to GP and noted to have high BP
Abdominal radiograph in AP supine view

Radiographic findings:

  • There is homogenous opacity lateral to lumbar spine on the left side
  • The opacity shows smooth convexity with fairly well defined lateral border (yellow arrows)
  • No obliteration of left psoas outline
  • Minimal displacement of bowel loops peripherally
Ultrasound in transverse planes
Ultrasound in sagittal and axial planes

Ultrasound findings:

  • Dilated abdominal aorta is seen from the level of superior mesenteric artery until the level of aortic bifurcation. The common iliac arteries are not dilated.
  • The diameter of abdominal aorta at the level of coeliac trunk and superior mesenteric artery measures 2.9 cm and 3.4 cm respectively.
  • The infra-renal abdominal aorta is much dilated and torturous; widest diameter of 8.1 cm. Thick luminal thrombus causing approximately 70% luminal stenosis. The true lumen measures 2.3 cm.
  • A sliver of fluid surrounding the posterior aspect of the thrombus is seen which suggest presence of a small intramural hematoma. However no definite flap is identified to indicate presence of dissection.
  • No free fluid in the abdominal cavity or in the retroperitoneal space to suggest aortic leak.

Diagnosis: Abdominal aortic aneurysm with no feature of leaking or dissection.

Discussion:

  • Abdominal aortic aneurysms are focal dilatations of the abdominal aorta measuring 50% greater than the proximal normal segment, or >3 cm in maximum diameter.
  • Fusiform type aneurysm is more common than saccular aneurysm.
  • Males are much more commonly affected than females (4:1 male/female ratio)
  • Ultrasound is optimal for general AAA screening and surveillance, The sensitivity and specificity approach 100%; however, it should be noted that visualization is poor in 1% to 3% of patients due to patient habitus or overlying bowel gas.
  • However, ultrasound does not provide sufficient detail for procedural planning or more complex lesions. Ultrasound cannot be reliably used in evaluation for endovascular treatments and assessment of regional branch vessels.
  • Intervention is usually performed if
    • Diameter >5.5 cm
    • enlargement in transverse diameter ≥5 mm in 6 months
    • Symptomatic lesion
Author: radhianahassan