Photo of Ingemar Fredriksson

Ingemar Fredriksson

Adjunct Associate Professor, Docent

My role in bridging academy and industry gives me a close connection to the “real world” in my research and teaching. My research is focused on biomedical optics with applications within biomedical equipment for assessment of the microcirculation.

Model based biomedical optics

The clinical potential in examining the status of the microcirculation, i.e. the blood flow in the smallest blood vessels in the body where the oxygen transfer between blood and cells takes place, is tremendous. Having tools for doing that in an objective and detailed manner is a key for learning more about this advanced system that is of obvious importance for all living cells of the body. It also facilitates better diagnosis of diseases affecting the microcirculation, such as diabetes and cardiovascular disease.

Light and its interaction with tissue has been utilized for some decades by now in instruments used to study the microcirculation. It is for example possible to study the small frequency shifts, Doppler shifts, that arise when light is scattered by moving red blood cells. That is done in laser Doppler flowmetry, a technique that was developed at the department of biomedical engineering during the 80’s to a large extent. As a spin off from that research, the company Perimed was formed, where I am employed today in addition to my employment at the department. The technique was revolutionary and lead to giant leaps forward in the understanding of the microcirculation. However, its clinical applicability is limited due to lack of detail in information about the blood flow that is delivered from today’s instruments.

My research is focused on using computer models, simulations, and optimization techniques in order to gain much more information from the measured signals and thus produce better blood flow measures. By using that approach, we can for example generate a speed resolved blood flow measure in absolute units, which is easier to interpret for the user and can be used to draw conclusions about flow in different vessel compartments. We have successfully used the concept not only within laser Doppler flowmetry but also within diffuse reflectance spectroscopy, enabling accurate estimation of red blood cell tissue fraction and their oxygen saturation. Those two techniques have been combined into a system that is now sold to clinical researchers by Perimed – the PF 6000 EPOS system (Enhanced Perfusion and Oxygen Saturation).

Until recently, I have foremost focused on point-wise measuring techniques, but that is now broadened to also include imaging techniques for gaining the same information over spatially resolved surfaces. The same model based principles can be applied within laser speckle contrast imaging for blood flow and hyperspectral imaging for tissue oxygen saturation.



Hanna Jonsson, Ingemar Fredriksson, Sara Bergstrand, Carl Johan Östgren, Marcus Larsson, Tomas Strömberg (2023) Absorption and reduced scattering coefficients in epidermis and dermis from a Swedish cohort study PHOTONICS IN DERMATOLOGY AND PLASTIC SURGERY 2023, Article 123520C Continue to DOI
Linda Samils, Joakim Henricson, Tomas Strömberg, Ingemar Fredriksson, Fredrik Iredahl (2023) Workload and sex effects in comprehensive assessment of cutaneous microcirculation Microvascular Research, Vol. 148, Article 104547 Continue to DOI
Martin Hultman, Marcus Larsson, Tomas Strömberg, Joakim Henricson, Fredrik Iredahl, Ingemar Fredriksson (2023) Flowmotion imaging analysis of spatiotemporal variations in skin microcirculatory perfusion Microvascular Research, Vol. 146, Article 104456 Continue to DOI
Martin Hultman, Marcus Larsson, Tomas Strömberg, Ingemar Fredriksson (2023) Speed-resolved perfusion imaging using multi-exposure laser speckle contrast imaging and machine learning Journal of Biomedical Optics, Vol. 28, Article 036007 Continue to DOI


Andres J. Rodriguez, Michael Alzamora, Ajmal Ajmal, Tananant Boonya-Ananta, Du Le Vinh Nguyen, Ingemar Fredriksson, Tomas Strömberg, Jessica C. Ramella-Roman (2022) In-vivo human study of skin optical properties in individuals with obesity OPTICAL DIAGNOSTICS AND SENSING XXII: TOWARD POINT-OF-CARE DIAGNOSTICS, Article 119680B Continue to DOI




Further reading