Non-invasive imaging of Peripheral Vascular Disease with MultiSpectral Optoacoustic Tomography (PVD-MSOT).

This study aims to investigate the feasibility and clinical performance of MSOT imaging of the feet in Peripheral Vascular (PVD) patients. Our main objective is to investigate and obtain new information about the state of arteries in PVD patients using MSOT. Our second objective is to investigate the use of MSOT compared to duplex ultrasound and standard diagnostic work-up (including Fontaine classification) in providing more information on microvascular perfusion and oxygenation in the extremities in relation to severity of the PVD.

A total of 24 patients diagnosed with PVD (Fontaine Classification II, III, and IV) will be imaged using MSOT in this non-randomized, non-blinded, prospective, single center feasibility study. The patients will be imaged on both feet at particular landmarks, which include large arteries (arteria tibialis posterior and dorsalis pedis) and microvasculature (on each of the toes). The images will be compared to duplex ultrasound images of the large arteries, which are acquired as part of the standard of care, as well as other available diagnostic information, including the Fontaine classification.

Peripheral vascular disease (PVD) is a highly prevalent disease associated with significant morbidity and mortality.
Current diagnostic procedures, such as duplex ultrasound examination, are not able to visualize the direct cause of the symptoms, namely insufficient oxygenated blood perfusion of the extremities. Multispectral Optoacoustic Tomography (MSOT) is an emerging imaging technique which is capable of real-time visualization of resolving hemoglobin in its different oxygenation states and perfusion.
It is therefore hypothesized that MSOT can become a valuable diagnostic vascular imaging tool, by directly visualizing perfusion and oxygenation of blood in the extremities, as well as providing new contrast for examining blood vessels in health and disease.

One time-point measurement after obtaining informed consent.

- MSOT imaging of the microvasculature will be performed on both feet at the arteriae tibialis posterior and dorsalis pedis, the medial side of the hallux, and plantar distal side of the phalanges.
- Pulse oximetry of each toe (10 in total) will be performed.
- The skin autofluorescence will be determined by an Advanced Glycation Endproducts (AGE) Reader and recorded.
- For comparison and validation of the MSOT images of the arteriae tibialis posterior and dorsalis pedis, duplex ultrasound imaging will be performed at these two landmarks by experienced vascular labtechnicians.
- Ankle-Brachial Index (ABI) will be measured by experienced vascular labtechnicians.
- Fontaine Classification as described in the Medical History will be recorded.