Photo of Hanna Jonasson

Hanna Jonasson

Associate Professor

Through the smallest vessels, the microcirculation, oxygen and nutrients reach all cells in the body. My research focuses on optical techniques to measure blood flow and oxygenation in skin microcirculation and how it changes in different diseases.

Quantifying skin microcirculation

My research is focused on development and clinical evaluation of optical techniques for quantification of skin microcirculation. The research is cross-border and includes both medicine and technique.

Optical techniques makes it possible to non-invasively measure blood flow and oxygenation in the microcirculation. We illuminate the skin with visible light, which will be scattered and absorbed by the tissue, and by analyzing the backscattered light, blood flow and oxygen saturation can be determined.

Oxygen saturation is determined by using the characteristic light absorption of blood, which is different if the blood is oxygenated or not. With white light illumination and by studying the backscattered light, the oxygenation of the microcirculation can be determined.

When light hits a moving red blood cells, the light frequency is altered. This phenomenon is called the Doppler effect and is influenced by the velocity of blood. Laser Doppler flowmetry is a method for estimating blood flow in microcirculation based on the light frequency shift.

Mathematical models are used to describe how light scatter in tissue and this can be simulated using Monte Carlo techniques. Simulations are then compared to measurements to quantify the oxygen saturation and blood flow in the microcirculation.

In diabetes and other diseases the elasticity of the blood vessel walls is changed, which affects the blood flow in the vessels. Part of my research is to investigate the relationship between changes in skin microcirculation and type 2 diabetes and cardiovascular disease.

I teach anatomy and physiology in the engineering programmes.


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