From the Guidelines
Duplex ultrasound is the primary test for evaluating iliac artery disease, with a sensitivity and specificity of approximately 90% to 95% for diagnosing stenoses > 50% in diameter from the iliac arteries to the popliteal arteries. This non-invasive test uses a combination of Doppler ultrasound and imaging to visualize blood flow and identify stenosis or occlusions in the iliac arteries 1. The accuracy of duplex ultrasound depends on the ability to visualize the vessel adequately, and the use of color Doppler can improve accuracy 1. However, accuracy can be diminished in examinations of the iliac arteries if bowel gas or tortuosity obscures the iliac vessels, or if dense calcification obscures flow 1.
Some key points to consider when using duplex ultrasound for iliac artery disease evaluation include:
- The test requires a highly skilled sonographer and can take over an hour to perform 1
- Duplex ultrasound can be used to choose between endovascular and surgical revascularization, but it is not satisfactory for evaluating tibial arteries for distal bypass or choosing specific treatment plans with a high degree of confidence 1
- CT angiography (CTA) or magnetic resonance angiography (MRA) can provide comprehensive imaging of the iliac arteries and are often used before interventional procedures, with CTA having a reported sensitivity and specificity of 96% and 98%, respectively, for detecting aorto-iliac stenoses >50% 1
In terms of other diagnostic tests, the ankle-brachial index (ABI) can be used as a primary test for evaluating iliac artery disease, but it is not as sensitive or specific as duplex ultrasound for diagnosing stenoses > 50% in diameter from the iliac arteries to the popliteal arteries. Conventional angiography may be performed in some cases, which involves injecting contrast dye into the arteries and taking X-ray images, but this test is invasive and allows for simultaneous diagnosis and treatment.
From the Research
Diagnostic Tests for Iliac Arteries
The diagnostic tests for iliac arteries include:
- Duplex ultrasound scanning 2, 3
- Computed Tomography Angiography (CTA) 3, 4, 5
- Contrast-enhanced ultrasound (CEUS) combined with CTA 5
- Color Doppler Ultrasound (CDU) 6
- Digital Subtraction Angiography (DSA) 3, 4, 5
Sensitivity and Specificity of Diagnostic Tests
The sensitivity and specificity of these tests vary:
- Duplex ultrasound scanning has a sensitivity of 93% and specificity of 91% in detecting significant stenoses 2
- CTA has a higher accuracy than duplex ultrasound in evaluating iliac arterial diseases, with a Cohen's kappa agreement of 1.0 3
- DE-SR with APR has a higher diagnostic accuracy than DE-SR or APR alone, with an accuracy of 95.20% 4
- Color Doppler Ultrasound can be used to detect endofibrosis of the iliac arteries, with abnormal waveforms and high peak systolic velocity (PSV) and end-diastolic velocity (EDV) seen in all limbs of athletes diagnosed with endofibrosis 6
Advantages and Limitations of Diagnostic Tests
The advantages and limitations of these tests include:
- Duplex ultrasound scanning is a reliable and non-invasive test, but may have limited sensitivity in low-flow segments distal to total occlusions 2
- CTA is a highly accurate test, but may require contrast-enhanced radiological imaging, which can be a limitation in some patients 3
- CEUS combined with CTA can provide more information about postoperative hemodynamics than CTA alone, but its role in postoperative follow-up of endovascular treatment of AAA needs to be further explored 5
- Color Doppler Ultrasound is a useful test for detecting endofibrosis of the iliac arteries, but may require pre- and postexercise imaging to diagnose the condition 6