César A González

Inductive Phase Shift Spectroscopy for Volumetric Brain Edema Detection: An Experimental Simulation

This study evaluates experimentally an induction based non-invasive technique for detection of changes of fluid volume through phase shift measurements as a possible method for volumetric brain edema monitoring. An induction coil - spherical head model was build and tested. The model involves two different diameter coils coaxially centered on a two- compartment glass sphere head model centrally placed with respect to the coils. Three different fluid volumes of physiological saline in 20 ml increments were used to simulate different edema levels. Phase shift of the impedance coils as a function of relative fluid volume was measured at five frequencies (40, 50, 100, 200 and 300 MHz) by a commercial vector network analyzer. The results show significant phase shift increase as a function of frequency and fluid volume. The experiments with the coil- spherical head system suggest that the tested technique has the potential to become a practical configuration for non-invasive volumetric brain edema monitoring.

New Wearable Body Sensor for Continuous Diagnosis of Internal Tissue Bleeding

Continuous monitoring of internal bleeding in tissue is essential for assessment and treatment of medical conditions. In this study we present a new body sensor for diagnosis of internal tissue bleeding based on contact multi-frequency electromagnetic inductive measurements of the tissue. This contributes to the existing family of body network sensors. This sensor can be used in emergency medicine in the field, in a hospital, or during daily life for patients at risk of bleeding. Unlike other sensors that detect bleeding, this sensor is portable, low cost, non-invasive and does not require galvanic coupling between the electrode and the tissue under measurement. Our study includes description of the new body sensor, criteria for data processing, basic diagnostic algorithms and calibration techniques. We show feasibility of this new sensor with a sensor prototype and diagnosis of an experimental simulation of internal bleeding and hypoperfusion conditions in the brain.