Ultrasonic Perfusion Estimation in Cuff Muscle

The purpose of this study is to evaluate the potential of ultrasound perfusion imaging technique for assessing the progression of peripheral arterial disease (PAD) and monitoring its response to therapy by measuring changes in microvessel alterations and perfusion variations.

The clinical manifestations of peripheral arterial disease (PAD), regardless of etiology, are due to a lack of blood flow to the musculature relative to its metabolism, which results in pain in the affected muscle groups. PAD affecting the lower extremities causes claudication, cramping pain in the calf, thigh or hip muscle induced by exercise. The initial test for evaluation of patients with claudication is ankle brachial index (ABI). Therefore, a non-invasive and affordable US technique that can quantify blood perfusion and microvasculature density, without using contrast agent, will improve PAD detection in early stage and can monitor the disease progress as well as the treatment response. The investigators anticipate that our new cost-effective and non-invasive ultrasound perfusion technique offers a quantitative imaging of perfusion that would help separating PAD from non-PAD and monitor the disease progression and treatment response.

Blood flow, Blood Vessel, Ischemia, Cuff muscle, Vascular, Ultrasound, Intermitant claudication, Cramp

The objective of this arm of the study is to evaluate the potentials of Ultrasound Perfusion imaging technique for early detection of peripheral arterial disease in patients and assess the disease progression and monitor the treatment response. The investigators anticipate that our new cost-effective and non-invasive ultrasound perfusion technique offers a quantitative imaging of perfusion and microvessels of cuff muscle that would separate PAD from non-PAD and help early detection of PAD and would help monitoring the disease progression and treatment response.

In this project, The investigators will use Alpinion ECUBE-12R (Alpinion, Bothell, WA) US platform. This state-of-the-art research US machine provides beam formed as well as Plane-Wave imaging options that allow high frame rate imaging. The investigators have characterized the acoustic output of this system for safe human studies and obtained the IRB approval for human studies. It should be noted that our technique is not limited to the Alpinion system; the investigators can also use other US systems, such as Verasonics, Vantage, (Redmond, WA). This technique can be adapted to other modern US machines in the future.

Aim 1: Determine the efficacy of ultrasonic perfusion imaging for early detection of PAD. The goal is to quantify the perfusion of cuff muscle in patients with lower leg claudication and compare the results to those obtained in healthy individuals

Perfusion density of the cuff muscle will be quantified by the new automatic ultrasound microvessel quantification technique and the resulting measurements will measure the outcome of this part of the study.

Aim 2: Determine the efficacy of ultrasonic perfusion imaging for assessment of treatment response in PAD patients. The goal is to quantify the perfusion of the cuff muscle in PAD patients in 3 time points, 6 months, and every year after treatment.

At each time point after the treatment, the perfusion density of the cuff muscle will be quantified by the new automatic ultrasound microvessel quantification technique and the resulting measurements will measure the outcome of this part of the study.

Inclusion Criteria: Male and female volunteers > 18 years old. Male and female volunteers with symptom of claudication and suspected peripheral arterial disease (PAD) who are scheduled for vascular testing. Exclusion Criteria: Patients with gangrene. Patients with lower leg amputation. Having ulcer and any health condition that does not allow proper use of ultrasound scanning. People considered in "vulnerable" populations.