Diagnostic Imaging Pathways in Peripheral Artery Disease: A Comparative Review of Duplex Ultrasound Through Computed Tomography Angiography

Abstract Peripheral artery disease (PAD) is a major global health challenge, affecting more than 200 million people worldwide and an estimated 8 to 12 million in the United States. Its clinical spectrum ranges from intermittent claudication to chronic limb-threatening ischemia and acute limb ischemia. Accurate vascular imaging is essential for diagnosis, risk stratification, treatment planning, and postprocedural surveillance, guiding management from conservative therapy to endovascular or surgical revascularization. In this review, we aim to summarize the contemporary imaging pathways in PAD, focusing on noninvasive methods—duplex ultrasound (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA)—and invasive strategies such as digital subtraction angiography (DSA) with adjunct intravascular imaging. DUS, with high sensitivity for detecting ≥50% stenosis, is a cost-effective, radiation-free first-line modality, though operator dependence and acoustic shadowing may limit accuracy in heavily calcified vessels. CTA offers rapid, high-resolution anatomical assessment but requires ionizing radiation and iodinated contrast. MRA provides excellent soft-tissue contrast without radiation, with noncontrast techniques such as quiescent-interval single-shot (QISS) mitigating gadolinium-related concerns in renal dysfunction. As of now, DSA remains the gold standard, with intravascular modalities including intravascular ultrasound and optical coherence tomography improving lesion characterization and optimizing endovascular therapy. Angioscopy and near-infrared spectroscopy contribute additional structural or lipid-content insights. Emerging technologies—photon-counting computed tomography (CT), photoacoustic imaging, and artificial intelligence-augmented analysis—promise enhanced resolution, reduced artifact burden, and improved physiological and molecular assessment. Current American College of Cardiology/American Heart Association and ESC guidelines endorse DUS as the initial diagnostic test, with CTA or MRA selected according to renal function, calcification severity, and revascularization planning needs. Tailoring imaging strategies to patient-specific characteristics enables more precise intervention, reduces amputation risk, and advances personalized PAD care.