The Value of Super-resolution Ultrasound Imaging for Peripheral Artery Disease

\*Inclusion Criteria:\* 1. Adults aged ≥18 years and ≤100 years; 2. Diagnosis of peripheral artery disease (PAD) confirmed by comprehensive clinical assessment-including characteristic symptoms (e.g., intermittent claudication, rest pain), physical findings (e.g., diminished or absent distal pulses, bruits), ankle-brachial index (ABI) \< 0.9, and corroborating vascular imaging (e.g., duplex ultrasonography, CTA, or MRA); 3. Alternatively, healthy adults without PAD (i.e., ABI ≥ 0.9, absence of suggestive symptoms or signs, and no history of atherosclerotic cardiovascular disease) who meet all other eligibility requirements; 4. Willing and able to provide written informed consent. \*Exclusion Criteria:\* 1. Inability to complete study procedures due to: 1. Severe involuntary movement disorders (e.g., advanced Parkinson's disease or cerebellar ataxia) interfering with image acquisition; 2. Contraindication to contrast-enhanced ultrasound (e.g., documented hypersensitivity to sulfur hexafluoride microbubble contrast agent \[SonoVue®\]); 3. Active lower-limb infection (e.g., diabetic foot infection with systemic signs or osteomyelitis), which precludes safe or interpretable data collection; 2. Cognitive impairment or legal incapacity precluding autonomous informed consent; 3. Refusal-by the participant or their legally authorized representative-to provide informed consent.