Lokale Suszeptibilitätsänderungen im Gehirn durch Reizung von Thermorezeptoren in der Haut

Recent MRI experiments have shown strong changes of susceptibility in the u-fibers of the brain by using thermal stimulation. The reason for this local effect in the u-fibers is unknown. In the course of this master-thesis the causes of these variations were identified and assessed by using specific tools.
The relation between the thermal influence und the ascertained change of susceptibility is investigated by using phase difference images. In order to generate selective temperature changes close to the body surface of the proband a thermal pad has been developed which provides the opportunity of temperature reporting simultaneously. Subsequently, the phase images, which were obtained with a gradient echo sequence by the 3T MRI scanner have been evaluated and local changes in susceptibility were calculated.
Reference and cooling measurements yielded reproducible results, which were evaluated by monitoring the phase trend in distinctive regions of the brain. The evaluation considered the respective underlying structure of the affected region of interest.
By analysing the phase difference images a reaction of the temperature receptor has been recognised as soon as the thermal stimulus has been achieved. The stimulus response was independent of the time duration and intensity of the stimulus.
Furtheron, there is the option to analyze the effects of thermal stimulation of the extremities in addition to the previous head measurements to check if the effect is triggered by thermal receptors only in the scalp.