A Non-significant Risk Clinical Study to Assess Perfusion Changes With Application of a TUS for Patients With PAD

Inclusion Criteria: 1. Age ≥22. 2. Diagnosis of infrapopliteal PAD. 3. Rutherford class 4 or 5 as determined by the investigator. 4. Toe Brachial Index (TBI) ≤ 0.6 OR Toe Blood Pressure ≤ 50 mmHg. Exclusion Criteria: 1. Prior stenting in posterior tibial, anterior tibial or peroneal artery. 2. Re-vascularization procedure within 25 days prior to enrollment in the study. (Note: Patients who had re-vascularization procedure earlier than 25 days prior to enrollment are eligible for enrollment if they meet other criteria). 3. Ulcers, cellulitis, or skin breakdown in treatment areas (posterior calf). 4. History or diagnosis of severe chronic venous insufficiency or mixed arterio-venous disease. 5. Acute limb ischemia within 30 days prior to treatment. 6. History or diagnosis of deep venous thrombosis below the knee in treatment leg. 7. Uncontrolled diabetes defined as HbA1c greater than 10%. 8. Ongoing hyperbaric oxygen treatment (HBOT) 9. Any conditions that, in the opinion of the investigator, may render the patient unable to complete the study or lead to difficulties for patient compliance with study requirements, or could confound study data. 9\. Patient's enrollment in another investigational study that has not completed the required primary endpoint follow-up period (Note: Patients involved in a long-term surveillance phase of another study are eligible for enrollment in this study).