Module «Skin Diagnosis»

Lymph Diagnostics in Skin Diseases

After delivery of a fluorescent marker into the skin, its clearance by the lymphatic vessels is monitored and quantified with a portable device, in order to detect impaired function of lymphatic vessels as early as possible.

M. Detmar (ETH), J.-C. Leroux (ETH), M. Meboldt (ETH), N. Lindenblatt (UZH/USZ), O. Distler (UZH/Balgrist/USZ)

Lymphedema is the consequence of impaired lymphatic vessel function and is characterized by chronic swelling of a limb. Most frequently, it develops after surgical dissection of lymph nodes in breast cancer patients. While there is no cure at present, early intervention may delay the progression of the disease. However, there are no reliable prognostic factors that allow to identify those patients who will develop lymphedema, and the lymphatic system imaging methods are invasive. This subproject aims at developing a simple and non-invasive method to quantify the function of lymphatic vessels to enable an earlier diagnosis of lymphedemas. To this end, we develop a new technique where a near-infrared fluorescent marker that is selectively taken up by lymphatics, is painlessly delivered into the skin. The decrease of the fluorescence signal from the skin over time represents the clearance of the marker by lymphatic vessels and is therefore a measure for their functionality. To record and analyze the signal, we develop a wearable detection device with remote data transfer to portable devices.

Biomechanical Analysis for Skin Diagnosis

Subsurface shear deformation profiles demonstrating strong gradients at the transition cutis - subcutis.

E. Mazza (ETH), O. Distler (UZH/USZ/Balgrist), O. Göksel (ETH), C. Schiestl (UZH/Kispi)

Scleroderma is associated with systemic modifications of skin microstructure, which are reflected in marked changes of biomechanical properties. Current methods for the assessment of pathological changes in the consistency of skin are based on a semi-quantitative subjective score performed by palpation of the skin. This project aims at identifying diagnostic factors based on a quantitative and objective measurement of mechanical parameters of superficial and deeper dermal tissue and on the characterization of the interaction of dermis, superficial fat and muscles. Parameters associated with the elastic as well as dissipative tissue behavior will be determined. To this end, quasi-static and dynamic measurement techniques will be used, such as elastography and tissue suction. Data analysis will be informed through patient specific finite element models of the skin and corresponding constitutive model equations. Non-invasive measurement techniques will be also applied to monitor integration of skin substitutes used to repair large wounds (collaboration with Kinderspital).

Skin diagnosis: Computer Assisted Assessment of Chronic Ulcers

Digital Ulcer Assessment
Eye tracking of digital ulcer assessment: heat map of gaze pattern.

O. Distler (UZH/Balgrist/USZ), M. Meboldt (ETH), W. Karlen (ETH)
J. Hafner (UZH/USZ), M. Calcagni (UZH/USZ), M. Berli (UZH/USZ), N. Lindenblatt (UZH/USZ)

Chronic ulcers significantly add to the burden of disease in patients with systemic sclerosis (SSc). Treatment is complicated by the fact that there is little consensus on diagnostic criteria of digital ulcers an their assessment. With the help of computer assisted image analysis and eye tracking this project seeks to understand how rheumatological experts assess these chronic ulcers (in comparison to non-experts) and what are the important features that enable successful assessment of these chronic wounds. This will help to develop guidelines for assessment and deliver information to eventually develop a computer assisted assessment of these chronic ulcers by a mobile application. The findings should be validated in a proof-of-concept study that shows improved treatment of digital ulcers in SSc patients.