Peripheral arterial disease assessment: wall, perfusion, and spectroscopy

Area of Science:

• Medical Imaging
• Cardiovascular Disease
• Biomedical Engineering

Background:

• Peripheral arterial disease (PAD) is a common condition caused by atherosclerosis, leading to lower limb arterial obstruction.
• Current diagnostic and follow-up methods for PAD, as well as assessment of new treatments, have limitations.

Purpose of the Study:

• To develop and evaluate novel magnetic resonance (MR) imaging techniques for diagnosing and monitoring peripheral arterial disease (PAD).
• To assess the potential of these MR examinations as quantitative endpoints in clinical trials for PAD therapies.

Main Methods:

• High-resolution black-blood imaging of superficial femoral artery atherosclerotic plaque.
• First-pass contrast-enhanced perfusion imaging of calf muscle during exercise using an MR-compatible pedal ergometer.
• Phosphorus-31 magnetic resonance (31P MR) spectroscopy to measure phosphocreatine (PCr) recovery kinetics during exercise.

Main Results:

• Black-blood imaging quantified atherosclerotic plaque volume in patients with mild to moderate PAD.
• Perfusion imaging showed stepwise increases in perfusion index from PAD patients to normal controls.
• PCr recovery time constants were significantly prolonged in PAD patients compared to controls (91.0s vs 34.7s, P < 0.0001).

Conclusions:

• Three distinct MR examinations were successfully developed and tested for peripheral arterial disease (PAD).
• These MR techniques effectively differentiate patients with mild to moderate PAD from healthy individuals.
• The developed MR examinations show potential as quantitative endpoints for clinical trials evaluating novel PAD therapies.