Oxygen equilibrium curves have been widely used to understand oxygen transport in numerous organisms. A major challenge has been to monitor oxygen binding characteristics and concomitant pH changes as they occur in vivo, in limited sample volumes. Here we report a technique allowing highly resolved and simultaneous monitoring of pH and blood pigment saturation in minute blood volumes. We equipp...

Diffuse optical imaging (DOI) allows the recovery of the hemodynamic response associated with evoked brain activity. The signal is contaminated with systemic physiological interference which occurs in the superficial layers of the head as well as in the brain tissue. The back-reflection geometry of the measurement makes the DOI signal strongly contaminated by systemic interference occurring in ...

Aims: As the utero-placental circulation have major impact on the fetus, and the placental function can be critical for determining fetal conditions, the placental oxygenation status was investigated. Methods: Near-infrared spectroscopy (NIRS) is a non-invasive technique used for the evaluation of regional tissue oxygenation in a number of organs. The trans-abdominal NIRS was developed as a non...

Functional near-infrared spectroscopy (fNIRS) is a non-invasive imaging approach for measuring brain activities based on changes in the cerebral concentrations of hemoglobin. Recently, statistical analysis based on a general linear model (GLM) has become popular. Here, to impose statistical significance on the activation detected by fNIRS, family-wise error (FWE) rate control is important. Howe...

We have developed a novel approach to allow for continuous imaging of concentration fields that evolve at surfaces due to release, uptake, and mass transport of molecules, without significant interference of the concentration fields by the chemical imaging itself. The technique utilizes optical "reporter" microbeads immobilized in a thin layer of transparent and inert hydrogel on top of the sur...

An efficient computation of the time-dependent forward solution for photon transport in a head model is a key capability for performing accurate inversion for functional diffuse optical imaging of the brain. The diffusion approximation to photon transport is much faster to simulate than the physically correct radiative transport equation (RTE); however, it is commonly assumed that scattering le...

Propagation of light in a highly scattering medium such as biological tissue is difficult to study. For complex geometry and multilayer structures computer simulation has to be used for light transport analysis. A Monte Carlo model of light propagation in tissue has been applied for the purpose of better understanding of the results of near-infrared spectroscopy (NIRS) measurements in experimen...