Clinical Use of Magnetic Resonance Perfusion Imaging to Qualitatively Assess Adequate Distal Perfusion After Endovascular Revascularization in Critical Limb Ischemia

Inclusion Criteria: * Age 20 and above * Critical limb ischemia with ulcer * Ankle brachial index(ABI) ≤ 0.9 or Toe brachial index (TBI) ≤ 0.5 or Transcutaneous oxygen pressure (TcPo2) ≤ 40mmHg * ≥ 70 percentage of stenosis of infrapopliteal artery on lower extremity computed tomography angiography or lower extremity doppler * Subject understands protocol and provides written, informed consent Exclusion Criteria: * Post-traumatic critical limb ischemia * Neurogenic limb ischemia * Life expectancy ≤ 2 years