Saturday, September 6, 2008 - 8:11PM EST

Diagnosis of Abdominal Aortic Aneurysm

Diagnostic Testing for Abdominal Aortic Aneurysm

Physical Examination

Because abdominal aortic aneurysms (AAA) often produce no symptoms, they are frequently detected during a routine physical examination. In fact, 75% of abdominal aortic aneurysms are detected during routine physical examination or during an unrelated radiological or surgical procedure. Conditions such as obesity, fluid in the abdomen, spinal malformations, and other medical conditions can make detection by physical examination alone very difficult or impossible.

General physical examination includes:

  • Examination of the abdominal region
  • Examination of the lower extremities
  • Measurement of blood pressure
  • Assessment of circulation (e.g., color, pulse, swelling)

Physical examination is the least effective part of the diagnostic work-up and is thought to accurately identify an abdominal aortic aneurysm in only 65% of cases. It is particularly ineffective for determining the presence of small aneurysms in obese individuals.

Laboratory Evaluation

  • Complete blood count (CBC)
  • Red blood count
  • White blood count
  • Serum creatinine levels - this test is used to evaluate kidney function

Radiological Studies

Abdominal ultrasound (sonogram) can identify AAA with nearly 100% accuracy and can measure anterior-posterior (front to back) as well as transverse (side to side) dimensions to within 0.3-0.4 cm.

Once the abdominal aortic aneurysm has been identified by ultrasound an abdominal computerized tomography (CAT) scan is usually done to assess:

  • Size (more precise measurement than ultrasound)
  • Anatomical features
  • Relationship to renal arteries
  • Indication of calcifications or thrombus
  • Unknown abdominal pathology that may impact on surgical repair of the AAA

The CT scan can measure the dimensions of an abdominal aortic aneurysm to within 0.03 cm. Precise measurement is crucial in order for the surgeon to plan a successful repair procedure. An angiogram with contrast dye may be combined with the CT scan to highlight vessel anatomy, aneurysm position, and its relationship to other structures.