Evaluation of Hyperspectral Imaging for Follow-Up Assessment after Revascularization in Peripheral Artery Disease.

BACKGROUND: Assessment of tissue oxygenation is an important aspect of detection and monitoring of patients with peripheral artery disease (PAD). Hyperspectral imaging (HSI) is a non-contact technology for assessing microcirculatory function by quantifying tissue oxygen saturation (StO2). This study investigated whether HSI can be used to monitor skin oxygenation in patients with PAD after appropriate treatment of the lower extremities. METHODS: For this purpose, 37 patients with PAD were studied by means of ankle-brachial index (ABI) and HSI before and after surgical or endovascular therapy. Thereby, the oxygenation parameter StO2 and near infrared (NIR) perfusion index were quantified in seven angiosomes on the diseased lower leg and foot. In addition, the effects of skin temperature and physical activity on StO2 and the NIR perfusion index and the respective inter-operator variability of these parameters were investigated in 25 healthy volunteers. RESULTS: In all patients, the ABI significantly increased after surgical and endovascular therapy. In parallel, HSI revealed significant changes in both StO2 and NIR perfusion index in almost all studied angiosomes depending on the performed treatment. The increase in tissue oxygenation saturation was especially pronounced after surgical treatment. Neither heat nor cold, nor physical activity, nor repeated assessments of HSI parameters by independent investigators significantly affected the results on StO2 and the NIR perfusion index. CONCLUSIONS: Tissue oxygen saturation data obtained with HSI are robust to external confounders, such as temperature and physical activity, and do not show inter-operator variability; therefore, can be used as an additional technique to established methods, such as the ABI, to monitor peripheral perfusion in patients with PAD.

Evaluation of peripheral artery disease with the TIVITA® Tissue hyperspectral imaging camera system.

BACKGROUND: Objective, reliable and easy screening for peripheral artery disease (PAD) is essential to confirm the diagnosis and initiate the respective treatment. Therefore, a new non-invasive hyperspectral camera (TIVITA® Tissue) was tested in patients with and without PAD. OBJECTIVE: It was hypothesized that the oxygenation parameters of the TIVITA® Tissue correlate to established modalities for detection of PAD and allow differentiation between individuals with and without PAD. METHODS: Evaluation of tissue oxygenation was performed in the angiosome of the medial plantar artery in 25 healthy young people and in 24 patients with and 25 patients without PAD in comparable age. Thereby, superficial oxygenation (StO2) and near-infrared (NIR) perfusion index were measured with the TIVITA® Tissue. Additionally, the ankle-brachial-index (ABI), the complaint free walking distance and the vascular quality of life were assessed and demographic data were obtained from all participants. RESULTS: TIVITA® Tissue analysis revealed significantly reduced StO2 and NIR perfusion index in PAD compared to healthy young participants and patients without PAD. StO2 and NIR perfusion index positively correlated with ABI, the complaint free walking distance and the vascular quality of life score. CONCLUSIONS: In summary, this new hyperspectral imaging camera bears great potential for PAD screening as well as for follow up.