The initial way of diagnosis is physical exam. Your doctor may be able to feel a pulsatile mass in the center of the abdomen and make the clinical diagnosis. In obese patients, physical exam is less helpful.
Listening with a stethoscope may also reveal a bruit or abnormal sound from turbulence of blood within the aneurysm.
X-rays can show calcium deposits in the aneurysm wall. But plain X-rays of the abdomen cannot determine the size and the extent of the aneurysm.
Ultrasonography usually gives a clear picture of the size of an aneurysm. Ultrasound has about 98% accuracy in measuring the size of the aneurysm and is safe and noninvasive.
CT scan of the abdomen is highly accurate in determining the size and extent of the aneurysm and its location in the aorta.
MRI/MRA (magnetic resonance imaging and arteriography) may be an alternative when CT scan can’t be a choice for certain patients.
Clinically, ultrasonography is the first choice because it’s safe, noninvasive and high accuracy. In preparing for surgery, CT scan (together with dye injection) or MRI is often used further.