Investigation of Lipedema, Lymphedema and Vascular Malformations by Multispectral Optoacoustic Tomography (MSOT)

This study aims to analyze the fatty tissue architecture of the subcutaneous tissue in patients from the plastic surgery department. Plastic surgery patients show a wide variety of subcutaneous fatty tissue structures during clinical examination. These include patients with edema of the extremities such as lipedema or lymphedema. Fatty tissue architecture plays a major role in our everyday lives, as wound healing and scar formation, for example, are influenced by the blood flow to the overlying skin. The fatty tissue architecture, especially in the subcutaneous fatty tissue, also plays a major role in our appearance. An analysis of the architecture can potentially provide information about the genesis of different skin fold formations. The aim of this study is to quantitatively describe structural differences in adipose tissue architecture. Adipose tissue architecture is still a largely unexplored area because imaging has not been possible to date. MSOT imaging is similar to conventional sonography in that a transducer is placed on the skin and energy is supplied to the tissue by pulsed laser light instead of sound. On a macroscopic level, this leads to a constant change of minimal oscillations of individual tissue components. The resulting sound waves can then be detected by the same transducer. Previous studies have shown that the quantitative determination of hemoglobin can be used to obtain information on blood circulation and inflammatory activity. In the extended spectrum, in contrast, not only hemoglobin and its oxygenation stages but also other biomarkers such as collagens and lipids can be detected. This is very useful for imaging of fat, lymphatics and normal and abnormal blood vessels in vascular malformations. This process was largely researched by the working group of Prof. Ntziachristos (Helmholtz Center Munich and Technical University of Munich) and Prof. Razansky (Eidgenösische Technische Hochschule Zurich) and is being further developed into a clinically applicable technology and sold commercially by the company iThera. As a first series of demonstrative clinical studies following rigorous technical development, MSOT will serve as a key tool for research partners in the investigation of several diseases that remain poorly-understood and have limited treatment options. These parallel studies will focus on lipedema and lymphedema as well as vascular malformations - three distinct disease groups with similarly unmet clinical needs for appropriate imaging modalities and high potential of translation to further major disease areas. By focusing on two unrelated diseases, this project will show the wide-reaching application of this innovative imaging approach. Following successful proof-of-principle validation in a clinical research environment, full exploitation and dissemination of the results will strive to deliver MSOT to the greater scientific community. The main objectives are to confirm/validate the spectral profile of fat and vasculature on MSOT in lipedema patients, to establish the spectral profile of vascular malformations based on MSOT for adults and children and to establish the spectral profile and imaging of lymphatic vessels. With a detailed analysis of the architecture, our understanding of the physiology and pathology of the skin may be enhanced.